1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875
//! Signature-related functionality. //! //! Signatures are one of the central data structures in OpenPGP. //! They are used to protect the integrity of both structured //! documents (e.g., timestamps) and unstructured documents (arbitrary //! byte sequences) as well as cryptographic data structures. //! //! The use of signatures to protect cryptographic data structures is //! central to making it easy to change an OpenPGP certificate. //! Consider how a certificate is initially authenticated. A user, //! say Alice, securely communicates her certificate's fingerprint to //! another user, say Bob. Alice might do this by personally handing //! Bob a business card with her fingerprint on it. When Bob is in //! front of his computer, he may then record that Alice uses the //! specified key. Technically, the fingerprint that he used only //! identifies the primary key: a fingerprint is the hash of the //! primary key; it does not say anything about any of the rest of the //! certificate---the subkeys, the User IDs, and the User Attributes. //! But, because these components are signed by the primary key, we //! know that the controller of the key intended that they be //! associated with the certificate. This mechanism makes it not only //! possible to add and revoke components, but also to change //! meta-data, such as a key's expiration time. If the fingerprint //! were instead computed over the whole OpenPGP certificate, then //! changing the certificate would result in a new fingerprint. In //! that case, the fingerprint could not be used as a long-term, //! unique, and stable identifier. //! //! Signatures are described in [Section 5.2 of RFC 4880]. //! //! # Data Types //! //! The main signature-related data type is the [`Signature`] enum. //! This enum abstracts away the differences between the signature //! formats (the deprecated [version 3], the current [version 4], and //! the proposed [version 5] formats). Nevertheless some //! functionality remains format specific. For instance, version 4 //! signatures introduced support for storing arbitrary key-value //! pairs (so-called [notations]). //! //! This version of Sequoia only supports version 4 signatures //! ([`Signature4`]). However, future versions may include limited //! support for version 3 signatures to allow working with archived //! messages, and we intend to add support for version 5 signatures //! once the new version of the specification has been finalized. //! //! When signing a document, a `Signature` is typically created //! indirectly by the [streaming `Signer`]. Similarly, a `Signature` //! packet is created as a side effect of parsing a signed message //! using the [`PacketParser`]. //! //! The [`SigntaureBuilder`] can be used to create a binding //! signature, a certification, etc. The motivation for having a //! separate data structure for creating signatures is that it //! decreases the chance that a half-constructed signature is //! accidentally exported. When modifying an existing signature, you //! can use, for instance, `SignatureBuilder::from` to convert a //! `Signtaure` into a `SigntaureBuilder`: //! //! ``` //! use sequoia_openpgp as openpgp; //! use openpgp::policy::StandardPolicy; //! # use openpgp::cert::prelude::*; //! # use openpgp::packet::prelude::*; //! //! # fn main() -> openpgp::Result<()> { //! let p = &StandardPolicy::new(); //! //! # // Generate a new certificate. It has secret key material. //! # let (cert, _) = CertBuilder::new() //! # .generate()?; //! # //! // Create a new direct key signature using the current one as a template. //! let pk = cert.with_policy(p, None)?.primary_key(); //! let sig = pk.direct_key_signature()?; //! let builder: SignatureBuilder = sig.clone().into(); //! # Ok(()) //! # } //! ``` //! //! For version 4 signatures, attributes are set using so-called //! subpackets. Subpackets can be stored in two places: either in the //! so-called hashed area or in the so-called unhashed area. Whereas //! the hashed area's integrity is protected by the signature, the //! unhashed area is not. Because an attacker can modify the unhashed //! area without detection, the unhashed area should only be used for //! storing self-authenticating data, e.g., the issuer, or a back //! signature. It is also sometimes used for [hints]. //! [`Signature::normalize`] removes unexpected subpackets from the //! unhashed area. However, due to a lack of context, it does not //! validate the remaining subpackets. //! //! In Sequoia, each subpacket area is represented by a //! [`SubpacketArea`] data structure. The two subpacket areas are //! unified by the [`SubpacketAreas`] data structure, which implements //! a reasonable policy for looking up subpackets. In particular, it //! prefers subpackets from the hashed subpacket area, and only //! consults the unhashed subpacket area for certain packets. See //! [its documentation] for details. //! //! [Section 5.2 of RFC 4880]: https://tools.ietf.org/html/rfc4880#section-5.2 //! [`Signature`]: ../enum.Signature.html //! [version 3]: https://tools.ietf.org/html/rfc1991#section-5.2.2 //! [version 4]: https://tools.ietf.org/html/rfc4880#section-5.2.3 //! [version 5]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#name-version-4-and-5-signature-p //! [notations]: https://tools.ietf.org/html/rfc4880#section-5.2.3.16 //! [`Signature4`]: struct.Signature4.html //! [streaming `Signer`]: ../../serialize/stream/struct.Signer.html //! [`PacketParser`]: ../../parse/index.html //! [`SigntaureBuilder`]: struct.SignatureBuilder.html //! [hints]: https://tools.ietf.org/html/rfc4880#section-5.13 //! [`Signature::normalize`]: ../enum.Signature.html#method.normalize //! [`SubpacketArea`]: subpacket/struct.SubpacketArea.html //! [`SubpacketAreas`]: subpacket/struct.SubpacketAreas.html //! [its documentation]: subpacket/struct.SubpacketAreas.html use std::fmt; use std::ops::{Deref, DerefMut}; use std::time::SystemTime; #[cfg(any(test, feature = "quickcheck"))] use quickcheck::{Arbitrary, Gen}; use crate::Error; use crate::Result; use crate::crypto::{ mpi, hash::{self, Hash}, Signer, }; use crate::HashAlgorithm; use crate::PublicKeyAlgorithm; use crate::SignatureType; use crate::packet::Signature; use crate::packet::{ key, Key, }; use crate::packet::UserID; use crate::packet::UserAttribute; use crate::Packet; use crate::packet; use crate::packet::signature::subpacket::{ SubpacketArea, SubpacketAreas, SubpacketTag, }; #[cfg(any(test, feature = "quickcheck"))] /// Like quickcheck::Arbitrary, but bounded. trait ArbitraryBounded { /// Generates an arbitrary value, but only recurses if `depth > /// 0`. fn arbitrary_bounded<G: Gen>(g: &mut G, depth: usize) -> Self; } #[cfg(any(test, feature = "quickcheck"))] /// Default depth when implementing Arbitrary using ArbitraryBounded. const DEFAULT_ARBITRARY_DEPTH: usize = 2; #[cfg(any(test, feature = "quickcheck"))] macro_rules! impl_arbitrary_with_bound { ($typ:path) => { impl Arbitrary for $typ { fn arbitrary<G: Gen>(g: &mut G) -> Self { Self::arbitrary_bounded( g, crate::packet::signature::DEFAULT_ARBITRARY_DEPTH) } } } } pub mod subpacket; /// The data stored in a `Signature` packet. /// /// This data structure contains exactly those fields that appear in a /// [`Signature` packet]. It is used by both the [`Signature4`] and /// the [`SignatureBuilder`] data structures, which include other /// auxiliary information. This data structure is public so that /// `Signature4` and `SignatureBuilder` can deref to it. /// /// A `SignatureField` derefs to a [`SubpacketAreas`]. /// /// [`Signature`]: https://tools.ietf.org/html/rfc4880#section-5.2 /// [`Signature4`]: struct.Signature4.html /// [`SignatureBuilder`]: struct.SignatureBuilder.html /// [`SubpacketAreas`]: subpacket/struct.SubpacketAreas.html #[derive(Clone, Hash, PartialEq, Eq)] pub struct SignatureFields { /// Version of the signature packet. Must be 4. version: u8, /// Type of signature. typ: SignatureType, /// Public-key algorithm used for this signature. pk_algo: PublicKeyAlgorithm, /// Hash algorithm used to compute the signature. hash_algo: HashAlgorithm, /// Subpackets. subpackets: SubpacketAreas, } #[cfg(any(test, feature = "quickcheck"))] impl ArbitraryBounded for SignatureFields { fn arbitrary_bounded<G: Gen>(g: &mut G, depth: usize) -> Self { SignatureFields { // XXX: Make this more interesting once we dig other // versions. version: 4, typ: Arbitrary::arbitrary(g), pk_algo: PublicKeyAlgorithm::arbitrary_for_signing(g), hash_algo: Arbitrary::arbitrary(g), subpackets: ArbitraryBounded::arbitrary_bounded(g, depth), } } } #[cfg(any(test, feature = "quickcheck"))] impl_arbitrary_with_bound!(SignatureFields); impl Deref for SignatureFields { type Target = SubpacketAreas; fn deref(&self) -> &Self::Target { &self.subpackets } } impl DerefMut for SignatureFields { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.subpackets } } impl SignatureFields { /// Gets the version. pub fn version(&self) -> u8 { self.version } /// Gets the signature type. /// /// This function is called `typ` and not `type`, because `type` /// is a reserved word. pub fn typ(&self) -> SignatureType { self.typ } /// Gets the public key algorithm. /// /// This is `pub(crate)`, because it shouldn't be exported by /// `SignatureBuilder` where it is only set at the end. pub(crate) fn pk_algo(&self) -> PublicKeyAlgorithm { self.pk_algo } /// Gets the hash algorithm. pub fn hash_algo(&self) -> HashAlgorithm { self.hash_algo } } /// A Signature builder. /// /// The `SignatureBuilder` is used to create [`Signature`]s. Although /// it can be used to generate a signature over a document (using /// [`SignatureBuilder::sign_message`]), it is usually better to use /// the [streaming `Signer`] for that. /// /// [`Signature`]: ../enum.Signature.html /// [streaming `Signer`]: ../../serialize/stream/struct.Signer.html /// [`SignatureBuilder::sign_message`]: #method.sign_message /// /// Oftentimes, you won't want to create a new signature from scratch, /// but modify a copy of an existing signature. This is /// straightforward to do since `SignatureBuilder` implements [`From`] /// for Signature. /// /// [`From`]: https://doc.rust-lang.org/stable/std/convert/trait.From.html /// /// According to [Section 5.2.3.4 of RFC 4880], `Signatures` must /// include a [`Signature Creation Time`] subpacket. Since this /// should usually be set to the current time, and is easy to forget /// to update, we remove any `Signature Creation Time` subpackets /// from both the hashed subpacket area and the unhashed subpacket /// area when converting a `Signature` to a `SignatureBuilder`, and /// when the `SignatureBuilder` is finalized, we automatically insert /// a `Signature Creation Time` subpacket with the current time into /// the hashed subpacket area unless the `Signature Creation Time` /// subpacket has been set using the [`set_signature_creation_time`] /// method or preserved using the [`preserve_signature_creation_time`] /// method or suppressed using the /// [`suppress_signature_creation_time`] method. /// /// [Section 5.2.3.4 of RFC 4880]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// [`suppress_signature_creation_time`]: #method.suppress_signature_creation_time /// /// Similarly, most OpenPGP implementations cannot verify a signature /// if neither the [`Issuer`] subpacket nor the [`Issuer Fingerprint`] /// subpacket has been correctly set. To avoid subtle bugs due to the /// use of a stale `Issuer` subpacket or a stale `Issuer Fingerprint` /// subpacket, we remove any `Issuer` subpackets, and `Issuer /// Fingerprint` subpackets from both the hashed and unhashed areas /// when converting a `Signature` to a `SigantureBuilder`. Since the /// [`Signer`] passed to the finalization routine contains the /// required information, we also automatically add appropriate /// `Issuer` and `Issuer Fingerprint` subpackets to the unhashed /// subpacket area when the `SignatureBuilder` is finalized unless an /// `Issuer` subpacket or an `IssuerFingerprint` subpacket has been /// added to either of the subpacket areas (which can be done using /// the [`set_issuer`] method and the [`set_issuer_fingerprint`] /// method, respectively). /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`Signer`]: ../../crypto/trait.Signer.html /// [`set_issuer`]: #method.set_issuer /// [`set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// To finalize the builder, call [`sign_hash`], [`sign_message`], /// [`sign_direct_key`], [`sign_subkey_binding`], /// [`sign_primary_key_binding`], [`sign_userid_binding`], /// [`sign_user_attribute_binding`], [`sign_standalone`], or /// [`sign_timestamp`], as appropriate. These functions turn the /// `SignatureBuilder` into a valid `Signature`. /// /// [`sign_hash`]: #method.sign_hash /// [`sign_message`]: #method.sign_message /// [`sign_direct_key`]: #method.sign_direct_key /// [`sign_subkey_binding`]: #method.sign_subkey_binding /// [`sign_primary_key_binding`]: #method.sign_primary_key_binding /// [`sign_userid_binding`]: #method.sign_userid_binding /// [`sign_user_attribute_binding`]: #method.sign_user_attribute_binding /// [`sign_standalone`]: #method.sign_standalone /// [`sign_timestamp`]: #method.sign_timestamp /// /// This structure `Deref`s to its containing [`SignatureFields`] /// structure, which in turn `Deref`s to its subpacket areas /// (a [`SubpacketAreas`]). /// /// [`SignatureFields`]: struct.SignatureFields.html /// [`SubpacketAreas`]: subpacket/struct.SubpacketAreas.html /// /// # Examples /// /// Update a certificate's feature set by updating the `Features` /// subpacket on any direct key signature, and any User ID binding /// signatures. See the [`Preferences`] trait for how preferences /// like these are looked up. /// /// [`Preferences`]: ../../cert/trait.Preferences.html /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::packet::signature::subpacket::{Subpacket, SubpacketValue}; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::Features; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().add_userid("Alice").generate()?; /// /// // Derive a signer (the primary key is always certification capable). /// let pk = cert.primary_key().key(); /// let mut signer = pk.clone().parts_into_secret()?.into_keypair()?; /// /// let mut sigs = Vec::new(); /// /// let vc = cert.with_policy(p, None)?; /// /// if let Ok(sig) = vc.direct_key_signature() { /// sigs.push(SignatureBuilder::from(sig.clone()) /// .modify_hashed_area(|mut a| { /// a.replace(Subpacket::new( /// SubpacketValue::Features(Features::sequoia().set(10)), /// false)?)?; /// Ok(a) /// })? /// // Update the direct key signature. /// .sign_direct_key(&mut signer, pk)?); /// } /// /// for ua in vc.userids() { /// sigs.push(SignatureBuilder::from(ua.binding_signature().clone()) /// .modify_hashed_area(|mut a| { /// a.replace(Subpacket::new( /// SubpacketValue::Features(Features::sequoia().set(10)), /// false)?)?; /// Ok(a) /// })? /// // Update the binding signature. /// .sign_userid_binding(&mut signer, pk, ua.userid())?); /// } /// /// // Merge in the new signatures. /// let cert = cert.merge_packets(sigs.into_iter().map(Packet::from))?; /// # assert_eq!(cert.bad_signatures().len(), 0); /// # Ok(()) /// # } /// ``` // IMPORTANT: If you add fields to this struct, you need to explicitly // IMPORTANT: implement PartialEq, Eq, and Hash. #[derive(Clone, Hash, PartialEq, Eq)] pub struct SignatureBuilder { overrode_creation_time: bool, original_creation_time: Option<SystemTime>, fields: SignatureFields, } impl Deref for SignatureBuilder { type Target = SignatureFields; fn deref(&self) -> &Self::Target { &self.fields } } impl DerefMut for SignatureBuilder { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.fields } } impl SignatureBuilder { /// Returns a new `SignatureBuilder` object. pub fn new(typ: SignatureType) -> Self { SignatureBuilder { overrode_creation_time: false, original_creation_time: None, fields: SignatureFields { version: 4, typ, pk_algo: PublicKeyAlgorithm::Unknown(0), hash_algo: HashAlgorithm::default(), subpackets: SubpacketAreas::default(), } } } /// Sets the signature type. pub fn set_type(mut self, t: SignatureType) -> Self { self.typ = t; self } /// Sets the hash algorithm. pub fn set_hash_algo(mut self, h: HashAlgorithm) -> Self { self.hash_algo = h; self } /// Generates a standalone signature. /// /// A [Standalone Signature] ([`SignatureType::Standalone`]) is a /// self-contained signature, which is only over the signature /// packet. /// /// [Standalone Signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// [`SignatureType::Standalone`]: ../../types/enum.SignatureType.html#variant.Standalone /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is [`SignatureType::Standalone`] or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`SignatureType::Timestamp`]: ../../types/enum.SignatureType.html#variant.Timestamp /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SignatureType; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().add_signing_subkey().generate()?; /// /// // Get a usable (alive, non-revoked) signing key. /// let key : &Key<_, _> = cert /// .keys().with_policy(p, None) /// .for_signing().alive().revoked(false).nth(0).unwrap().key(); /// // Derive a signer. /// let mut signer = key.clone().parts_into_secret()?.into_keypair()?; /// /// let sig = SignatureBuilder::new(SignatureType::Standalone) /// .sign_standalone(&mut signer)?; /// /// // Verify it. /// sig.verify_standalone(signer.public())?; /// # Ok(()) /// # } /// ``` pub fn sign_standalone(mut self, signer: &mut dyn Signer) -> Result<Signature> { match self.typ { SignatureType::Standalone => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(signer)?; let digest = Signature::hash_standalone(&self)?; self.sign(signer, digest) } /// Generates a Timestamp Signature. /// /// Like a [Standalone Signature] (created using /// [`SignatureBuilder::sign_standalone`]), a [Timestamp /// Signature] is a self-contained signature, but its emphasis in /// on the contained timestamp, specifically, the timestamp stored /// in the [`Signature Creation Time`] subpacket. This type of /// signature is primarily used by [timestamping services]. To /// timestamp a signature, you can include either a [Signature /// Target subpacket] (set using /// [`SignatureBuilder::set_signature_target`]), or an [Embedded /// Signature] (set using /// [`SignatureBuilder::set_embedded_signature`]) in the hashed /// area. /// /// /// [Standalone Signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// [`SignatureBuilder::sign_standalone`]: #method.sign_standalone /// [Timestamp Signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [timestamping services]: https://en.wikipedia.org/wiki/Trusted_timestamping /// [Signature Target subpacket]: https://tools.ietf.org/html/rfc4880#section-5.2.3.25 /// [`SignatureBuilder::set_signature_target`]: #method.set_signature_target /// [Embedded Signature]: https://tools.ietf.org/html/rfc4880#section-5.2.3.26 /// [`SignatureBuilder::set_embedded_signature`]: #method.set_embedded_signature /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is [`SignatureType::Timestamp`] or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`SignatureType::Timestamp`]: ../../types/enum.SignatureType.html#variant.Timestamp /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Create a timestamp signature: /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SignatureType; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().add_signing_subkey().generate()?; /// /// // Get a usable (alive, non-revoked) signing key. /// let key : &Key<_, _> = cert /// .keys().with_policy(p, None) /// .for_signing().alive().revoked(false).nth(0).unwrap().key(); /// // Derive a signer. /// let mut signer = key.clone().parts_into_secret()?.into_keypair()?; /// /// let sig = SignatureBuilder::new(SignatureType::Timestamp) /// .sign_timestamp(&mut signer)?; /// /// // Verify it. /// sig.verify_timestamp(signer.public())?; /// # Ok(()) /// # } /// ``` pub fn sign_timestamp(mut self, signer: &mut dyn Signer) -> Result<Signature> { match self.typ { SignatureType::Timestamp => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(signer)?; let digest = Signature::hash_timestamp(&self)?; self.sign(signer, digest) } /// Generates a Direct Key Signature. /// /// A [Direct Key Signature] is a signature over the primary key. /// It is primarily used to hold fallback [preferences]. For /// instance, when addressing the Certificate by a User ID, the /// OpenPGP implementation is supposed to look for preferences /// like the [Preferred Symmetric Algorithms] on the User ID, and /// only if there is no such packet, look on the direct key /// signature. /// /// This function is also used to create a [Key Revocation /// Signature], which revokes the certificate. /// /// [preferences]: ../../cert/trait.Preferences.html /// [Direct Key Signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// [Preferred Symmetric Algorithms]: https://tools.ietf.org/html/rfc4880#section-5.2.3.7 /// [Key Revocation Signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is [`SignatureType::DirectKey`], /// [`SignatureType::KeyRevocation`], or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`SignatureType::DirectKey`]: ../../types/enum.SignatureType.html#variant.DirectKey /// [`SignatureType::KeyRevocation`]: ../../types/enum.SignatureType.html#variant.KeyRevocation /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Set the default value for the [Preferred Symmetric Algorithms /// subpacket]: /// /// [Preferred Symmetric Algorithms subpacket]: #method.set_preferred_symmetric_algorithms /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SignatureType; /// use openpgp::types::SymmetricAlgorithm; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().add_signing_subkey().generate()?; /// /// // Get a usable (alive, non-revoked) certification key. /// let key : &Key<_, _> = cert /// .keys().with_policy(p, None) /// .for_certification().alive().revoked(false).nth(0).unwrap().key(); /// // Derive a signer. /// let mut signer = key.clone().parts_into_secret()?.into_keypair()?; /// /// // A direct key signature is always over the primary key. /// let pk = cert.primary_key().key(); /// /// // Modify the existing direct key signature. /// let sig = SignatureBuilder::from( /// cert.with_policy(p, None)?.direct_key_signature()?.clone()) /// .set_preferred_symmetric_algorithms( /// vec![ SymmetricAlgorithm::AES256, /// SymmetricAlgorithm::AES128, /// ])? /// .sign_direct_key(&mut signer, pk)?; /// /// // Verify it. /// sig.verify_direct_key(signer.public(), pk)?; /// # Ok(()) /// # } /// ``` pub fn sign_direct_key<P>(mut self, signer: &mut dyn Signer, pk: &Key<P, key::PrimaryRole>) -> Result<Signature> where P: key::KeyParts, { match self.typ { SignatureType::DirectKey => (), SignatureType::KeyRevocation => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(signer)?; let digest = Signature::hash_direct_key(&self, pk)?; self.sign(signer, digest) } /// Generates a User ID binding signature. /// /// A User ID binding signature (a self signature) or a [User ID /// certification] (a third-party signature) is a signature over a /// `User ID` and a `Primary Key` made by a certification-capable /// key. It asserts that the signer is convinced that the `User /// ID` should be associated with the `Certificate`, i.e., that /// the binding is authentic. /// /// [User ID certification]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// /// OpenPGP has four types of `User ID` certifications. They are /// intended to express the degree of the signer's conviction, /// i.e., how well the signer authenticated the binding. In /// practice, the `Positive Certification` type is used for /// self-signatures, and the `Generic Certification` is used for /// third-party certifications; the other types are not normally /// used. /// /// This function is also used to create [Certification /// Revocations]. /// /// [Certification Revocations]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is [`GenericCertification`], /// [`PersonaCertification`], [`CasualCertification`], /// [`PositiveCertification`], [`CertificationRevocation`], or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`GenericCertification`]: ../../types/enum.SignatureType.html#variant.GenericCertification /// [`PersonaCertification`]: ../../types/enum.SignatureType.html#variant.PersonaCertification /// [`CasualCertification`]: ../../types/enum.SignatureType.html#variant.CasualCertification /// [`PositiveCertification`]: ../../types/enum.SignatureType.html#variant.PositiveCertification /// [`CertificationRevocation`]: ../../types/enum.SignatureType.html#variant.CertificationRevocation /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Set the [Preferred Symmetric Algorithms subpacket], which will /// be used when addressing the certificate via the associated /// User ID: /// /// [Preferred Symmetric Algorithms subpacket]: #method.set_preferred_symmetric_algorithms /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SymmetricAlgorithm; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().add_userid("Alice").generate()?; /// /// // Get a usable (alive, non-revoked) certification key. /// let key : &Key<_, _> = cert /// .keys().with_policy(p, None) /// .for_certification().alive().revoked(false).nth(0).unwrap().key(); /// // Derive a signer. /// let mut signer = key.clone().parts_into_secret()?.into_keypair()?; /// /// let pk = cert.primary_key().key(); /// /// // Update the User ID's binding signature. /// let ua = cert.with_policy(p, None)?.userids().nth(0).unwrap(); /// let new_sig = SignatureBuilder::from( /// ua.binding_signature().clone()) /// .set_preferred_symmetric_algorithms( /// vec![ SymmetricAlgorithm::AES256, /// SymmetricAlgorithm::AES128, /// ])? /// .sign_userid_binding(&mut signer, pk, ua.userid())?; /// /// // Verify it. /// new_sig.verify_userid_binding(signer.public(), pk, ua.userid())?; /// # Ok(()) /// # } /// ``` pub fn sign_userid_binding<P>(mut self, signer: &mut dyn Signer, key: &Key<P, key::PrimaryRole>, userid: &UserID) -> Result<Signature> where P: key::KeyParts, { match self.typ { SignatureType::GenericCertification => (), SignatureType::PersonaCertification => (), SignatureType::CasualCertification => (), SignatureType::PositiveCertification => (), SignatureType::CertificationRevocation => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(signer)?; let digest = Signature::hash_userid_binding(&self, key, userid)?; self.sign(signer, digest) } /// Generates a subkey binding signature. /// /// A [subkey binding signature] is a signature over the primary /// key and a subkey, which is made by the primary key. It is an /// assertion by the certificate that the subkey really belongs to /// the certificate. That is, it binds the subkey to the /// certificate. /// /// Note: this function does not create a back signature, which is /// needed by certification-capable, signing-capable, and /// authentication-capable subkeys. A back signature can be /// created using [`SignatureBuilder::sign_primary_key_binding`]. /// /// This function is also used to create subkey revocations. /// /// [subkey binding signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// [`SignatureBuilder::sign_primary_key_binding`]: #method.sign_primary_key_binding /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is /// [`SignatureType::SubkeyBinding`], [`SignatureType::SubkeyRevocation`], or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`SignatureType::SubkeyBinding`]: ../../types/enum.SignatureType.html#variant.SubkeyBinding /// [`SignatureType::SubkeyRevocation`]: ../../types/enum.SignatureType.html#variant.SubkeyRevocation /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Add a new subkey intended for encrypting data in motion to an /// existing certificate: /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::KeyFlags; /// use openpgp::types::SignatureType; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().generate()?; /// # assert_eq!(cert.keys().count(), 1); /// /// let pk = cert.primary_key().key().clone().parts_into_secret()?; /// // Derive a signer. /// let mut pk_signer = pk.clone().into_keypair()?; /// /// // Generate an encryption subkey. /// let mut subkey: Key<_, _> = Key4::generate_rsa(3072)?.into(); /// // Derive a signer. /// let mut sk_signer = subkey.clone().into_keypair()?; /// /// let sig = SignatureBuilder::new(SignatureType::SubkeyBinding) /// .set_key_flags(&KeyFlags::empty().set_transport_encryption())? /// .sign_subkey_binding(&mut pk_signer, &pk, &subkey)?; /// /// let cert = cert.merge_packets(vec![Packet::SecretSubkey(subkey), /// sig.into()])?; /// /// assert_eq!(cert.with_policy(p, None)?.keys().count(), 2); /// # Ok(()) /// # } /// ``` pub fn sign_subkey_binding<P, Q>(mut self, signer: &mut dyn Signer, primary: &Key<P, key::PrimaryRole>, subkey: &Key<Q, key::SubordinateRole>) -> Result<Signature> where P: key::KeyParts, Q: key::KeyParts, { match self.typ { SignatureType::SubkeyBinding => (), SignatureType::SubkeyRevocation => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(signer)?; let digest = Signature::hash_subkey_binding(&self, primary, subkey)?; self.sign(signer, digest) } /// Generates a primary key binding signature. /// /// A [primary key binding signature], also referred to as a back /// signature or backsig, is a signature over the primary key and /// a subkey, which is made by the subkey. This signature is a /// statement by the subkey that it belongs to the primary key. /// That is, it binds the certificate to the subkey. It is /// normally stored in the subkey binding signature (see /// [`SignatureBuilder::sign_subkey_binding`]) in the [`Embedded /// Signature`] subpacket (set using /// [`SignatureBuilder::set_embedded_signature`]). /// /// [primary key binding signature]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// [`SignatureBuilder::sign_subkey_binding`]: #method.sign_subkey_binding /// [`Embedded Signature`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.26 /// [`SignatureBuilder::set_embedded_signature`]: #method.set_embedded_signature /// /// All subkeys that make signatures of any sort (signature /// subkeys, certification subkeys, and authentication subkeys) /// must include this signature in their binding signature. This /// signature ensures that an attacker (Mallory) can't claim /// someone else's (Alice's) signing key by just creating a subkey /// binding signature. If that were the case, anyone who has /// Mallory's certificate could be tricked into thinking that /// Mallory made signatures that were actually made by Alice. /// This signature prevents this attack, because it proves that /// the person who controls the private key for the primary key /// also controls the private key for the subkey and therefore /// intended that the subkey be associated with the primary key. /// Thus, although Mallory controls his own primary key and can /// issue a subkey binding signature for Alice's signing key, he /// doesn't control her signing key, and therefore can't create a /// valid backsig. /// /// A primary key binding signature is not needed for /// encryption-capable subkeys. This is firstly because /// encryption-capable keys cannot make signatures. But also /// because an attacker doesn't gain anything by adopting an /// encryption-capable subkey: without the private key material, /// they still can't read the message's content. /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is /// [`SignatureType::PrimaryKeyBinding`], or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`SignatureType::PrimaryKeyBinding`]: ../../types/enum.SignatureType.html#variant.PrimaryKeyBinding /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Add a new signing-capable subkey to an existing certificate. /// Because we are adding a signing-capable subkey, the binding /// signature needs to include a backsig. /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::KeyFlags; /// use openpgp::types::SignatureType; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().generate()?; /// # assert_eq!(cert.keys().count(), 1); /// /// let pk = cert.primary_key().key().clone().parts_into_secret()?; /// // Derive a signer. /// let mut pk_signer = pk.clone().into_keypair()?; /// /// // Generate a signing subkey. /// let mut subkey: Key<_, _> = Key4::generate_rsa(3072)?.into(); /// // Derive a signer. /// let mut sk_signer = subkey.clone().into_keypair()?; /// /// let sig = SignatureBuilder::new(SignatureType::SubkeyBinding) /// .set_key_flags(&KeyFlags::empty().set_signing())? /// // The backsig. This is essential for subkeys that create signatures! /// .set_embedded_signature( /// SignatureBuilder::new(SignatureType::PrimaryKeyBinding) /// .sign_primary_key_binding(&mut sk_signer, &pk, &subkey)?)? /// .sign_subkey_binding(&mut pk_signer, &pk, &subkey)?; /// /// let cert = cert.merge_packets(vec![Packet::SecretSubkey(subkey), /// sig.into()])?; /// /// assert_eq!(cert.with_policy(p, None)?.keys().count(), 2); /// # assert_eq!(cert.bad_signatures().len(), 0); /// # Ok(()) /// # } /// ``` pub fn sign_primary_key_binding<P, Q>(mut self, subkey_signer: &mut dyn Signer, primary: &Key<P, key::PrimaryRole>, subkey: &Key<Q, key::SubordinateRole>) -> Result<Signature> where P: key::KeyParts, Q: key::KeyParts, { match self.typ { SignatureType::PrimaryKeyBinding => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(subkey_signer)?; let digest = Signature::hash_primary_key_binding(&self, primary, subkey)?; self.sign(subkey_signer, digest) } /// Generates a User Attribute binding signature. /// /// A User Attribute binding signature or certification, a type of /// [User ID certification], is a signature over a User Attribute /// and a Primary Key. It asserts that the signer is convinced /// that the User Attribute should be associated with the /// Certificate, i.e., that the binding is authentic. /// /// [User ID certification]: https://tools.ietf.org/html/rfc4880#section-5.2.1 /// /// OpenPGP has four types of User Attribute certifications. They /// are intended to express the degree of the signer's conviction. /// In practice, the `Positive Certification` type is used for /// self-signatures, and the `Generic Certification` is used for /// third-party certifications; the other types are not normally /// used. /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is [`GenericCertification`], /// [`PersonaCertification`], [`CasualCertification`], /// [`PositiveCertification`], [`CertificationRevocation`], or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`GenericCertification`]: ../../types/enum.SignatureType.html#variant.GenericCertification /// [`PersonaCertification`]: ../../types/enum.SignatureType.html#variant.PersonaCertification /// [`CasualCertification`]: ../../types/enum.SignatureType.html#variant.CasualCertification /// [`PositiveCertification`]: ../../types/enum.SignatureType.html#variant.PositiveCertification /// [`CertificationRevocation`]: ../../types/enum.SignatureType.html#variant.CertificationRevocation /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Add a new User Attribute to an existing certificate: /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SignatureType; /// # use openpgp::packet::user_attribute::{Subpacket, Image}; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// # // Add a bare user attribute. /// # let ua = UserAttribute::new(&[ /// # Subpacket::Image( /// # Image::Private(100, vec![0, 1, 2].into_boxed_slice())), /// # ])?; /// # /// let (cert, _) = CertBuilder::new().generate()?; /// # assert_eq!(cert.user_attributes().count(), 0); /// /// // Add a user attribute. /// /// // Get a usable (alive, non-revoked) certification key. /// let key : &Key<_, _> = cert /// .keys().with_policy(p, None) /// .for_certification().alive().revoked(false).nth(0).unwrap().key(); /// // Derive a signer. /// let mut signer = key.clone().parts_into_secret()?.into_keypair()?; /// /// let pk = cert.primary_key().key(); /// /// let sig = SignatureBuilder::new(SignatureType::PositiveCertification) /// .sign_user_attribute_binding(&mut signer, pk, &ua)?; /// /// // Verify it. /// sig.verify_user_attribute_binding(signer.public(), pk, &ua)?; /// /// let cert = cert.merge_packets(vec![Packet::from(ua), sig.into()])?; /// assert_eq!(cert.with_policy(p, None)?.user_attributes().count(), 1); /// # Ok(()) /// # } /// ``` pub fn sign_user_attribute_binding<P>(mut self, signer: &mut dyn Signer, key: &Key<P, key::PrimaryRole>, ua: &UserAttribute) -> Result<Signature> where P: key::KeyParts, { match self.typ { SignatureType::GenericCertification => (), SignatureType::PersonaCertification => (), SignatureType::CasualCertification => (), SignatureType::PositiveCertification => (), SignatureType::CertificationRevocation => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } self = self.pre_sign(signer)?; let digest = Signature::hash_user_attribute_binding(&self, key, ua)?; self.sign(signer, digest) } /// Generates a signature. /// /// This is a low-level function. Normally, you'll want to use /// one of the higher-level functions, like /// [`SignatureBuilder::sign_userid_binding`]. But, this function /// is useful if you want to create a [`Signature`] for an /// unsupported signature type. /// /// [`SignatureBuilder::sign_userid_binding`]: #method.sign_userid_binding /// [`Signature`]: ../enum.Signature.html /// /// The `Signature`'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time pub fn sign_hash(mut self, signer: &mut dyn Signer, mut hash: hash::Context) -> Result<Signature> { self.hash_algo = hash.algo(); self = self.pre_sign(signer)?; self.hash(&mut hash); let mut digest = vec![0u8; hash.digest_size()]; hash.digest(&mut digest); self.sign(signer, digest) } /// Signs a message. /// /// Normally, you'll want to use the [streaming `Signer`] to sign /// a message. /// /// [streaming `Signer`]: ../../serialize/stream/struct.Signer.html /// /// OpenPGP supports two types of signatures over messages: binary /// and text. The text version normalizes line endings. But, /// since nearly all software today can deal with both Unix and /// DOS line endings, it is better to just use the binary version /// even when dealing with text. This avoids any possible /// ambiguity. /// /// This function checks that the [signature type] (passed to /// [`SignatureBuilder::new`], set via /// [`SignatureBuilder::set_type`], or copied when using /// `SignatureBuilder::From`) is [`Binary`], [`Text`], or /// [`SignatureType::Unknown`]. /// /// [signature type]: ../../types/enum.SignatureType.html /// [`SignatureBuilder::new`]: #method.new /// [`SignatureBuilder::set_type`]: #method.set_type /// [`Binary`]: ../../types/enum.SignatureType.html#variant.Binary /// [`Text`]: ../../types/enum.SignatureType.html#variant.Text /// [`SignatureType::Unknown`]: ../../types/enum.SignatureType.html#variant.Unknown /// /// The [`Signature`]'s public-key algorithm field is set to the /// algorithm used by `signer`. /// /// [`Signature`]: ../enum.Signature.html /// /// If neither an [`Issuer`] subpacket (set using /// [`SignatureBuilder::set_issuer`], for instance) nor an /// [`Issuer Fingerprint`] subpacket (set using /// [`SignatureBuilder::set_issuer_fingerprint`], for instance) is /// set, they are both added to the new `Signature`'s unhashed /// subpacket area and set to the `signer`'s `KeyID` and /// `Fingerprint`, respectively. /// /// [`Issuer`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [`SignatureBuilder::set_issuer`]: #method.set_issuer /// [`Issuer Fingerprint`]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// [`SignatureBuilder::set_issuer_fingerprint`]: #method.set_issuer_fingerprint /// /// Likewise, a [`Signature Creation Time`] subpacket set to the /// current time is added to the hashed area if the `Signature /// Creation Time` subpacket hasn't been set using, for instance, /// the [`set_signature_creation_time`] method or the /// [`preserve_signature_creation_time`] method. /// /// [`Signature Creation Time`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.4 /// [`set_signature_creation_time`]: #method.set_signature_creation_time /// [`preserve_signature_creation_time`]: #method.preserve_signature_creation_time /// /// # Examples /// /// Signs a document. For large messages, you should use the /// [streaming `Signer`], which streams the message's content. /// /// [streaming `Signer`]: ../../serialize/stream/struct.Signer.html /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SignatureType; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().generate()?; /// /// // Get a usable (alive, non-revoked) certification key. /// let key : &Key<_, _> = cert /// .keys().with_policy(p, None) /// .for_certification().alive().revoked(false).nth(0).unwrap().key(); /// // Derive a signer. /// let mut signer = key.clone().parts_into_secret()?.into_keypair()?; /// /// // For large messages, you should use openpgp::serialize::stream::Signer, /// // which streams the message's content. /// let msg = b"Hello, world!"; /// let sig = SignatureBuilder::new(SignatureType::Binary) /// .sign_message(&mut signer, msg)?; /// /// // Verify it. /// sig.verify_message(signer.public(), msg)?; /// # Ok(()) /// # } /// ``` pub fn sign_message<M>(mut self, signer: &mut dyn Signer, msg: M) -> Result<Signature> where M: AsRef<[u8]> { match self.typ { SignatureType::Binary => (), SignatureType::Text => (), SignatureType::Unknown(_) => (), _ => return Err(Error::UnsupportedSignatureType(self.typ).into()), } // Hash the message let mut hash = self.hash_algo.context()?; hash.update(msg.as_ref()); self = self.pre_sign(signer)?; self.hash(&mut hash); let mut digest = vec![0u8; hash.digest_size()]; hash.digest(&mut digest); self.sign(signer, digest) } fn pre_sign(mut self, signer: &dyn Signer) -> Result<Self> { self.pk_algo = signer.public().pk_algo(); // Set the creation time. if ! self.overrode_creation_time { self = self.set_signature_creation_time( std::time::SystemTime::now())?; } // Make sure we have an issuer packet. if self.issuers().next().is_none() && self.issuer_fingerprints().next().is_none() { self = self.set_issuer(signer.public().keyid())? .set_issuer_fingerprint(signer.public().fingerprint())?; } self.sort(); Ok(self) } fn sign(self, signer: &mut dyn Signer, digest: Vec<u8>) -> Result<Signature> { let mpis = signer.sign(self.hash_algo, &digest)?; Ok(Signature4 { common: Default::default(), fields: self.fields, digest_prefix: [digest[0], digest[1]], mpis, computed_digest: Some(digest), level: 0, }.into()) } } impl From<Signature> for SignatureBuilder { fn from(sig: Signature) -> Self { match sig { Signature::V4(sig) => sig.into(), Signature::__Nonexhaustive => unreachable!(), } } } impl From<Signature4> for SignatureBuilder { fn from(sig: Signature4) -> Self { let mut fields = sig.fields; let creation_time = fields.signature_creation_time(); fields.hashed_area_mut().remove_all(SubpacketTag::SignatureCreationTime); fields.hashed_area_mut().remove_all(SubpacketTag::Issuer); fields.hashed_area_mut().remove_all(SubpacketTag::IssuerFingerprint); fields.unhashed_area_mut().remove_all(SubpacketTag::SignatureCreationTime); fields.unhashed_area_mut().remove_all(SubpacketTag::Issuer); fields.unhashed_area_mut().remove_all(SubpacketTag::IssuerFingerprint); SignatureBuilder { overrode_creation_time: false, original_creation_time: creation_time, fields: fields, } } } /// Holds a v4 Signature packet. /// /// This holds a [version 4] Signature packet. Normally, you won't /// directly work with this data structure, but with the [`Signature`] /// enum, which is version agnostic. An exception is when you need to /// do version-specific operations. But currently, there aren't any /// version-specific methods. /// /// [version 4]: https://tools.ietf.org/html/rfc4880#section-5.2 /// [`Signature`]: ../enum.Signature.html #[derive(Clone)] pub struct Signature4 { /// CTB packet header fields. pub(crate) common: packet::Common, /// Fields as configured using the SignatureBuilder. pub(crate) fields: SignatureFields, /// Upper 16 bits of the signed hash value. digest_prefix: [u8; 2], /// Signature MPIs. mpis: mpi::Signature, /// When used in conjunction with a one-pass signature, this is the /// hash computed over the enclosed message. computed_digest: Option<Vec<u8>>, /// Signature level. /// /// A level of 0 indicates that the signature is directly over the /// data, a level of 1 means that the signature is a notarization /// over all level 0 signatures and the data, and so on. level: usize, } impl fmt::Debug for Signature4 { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { f.debug_struct("Signature4") .field("version", &self.version()) .field("typ", &self.typ()) .field("pk_algo", &self.pk_algo()) .field("hash_algo", &self.hash_algo()) .field("hashed_area", self.hashed_area()) .field("unhashed_area", self.unhashed_area()) .field("digest_prefix", &crate::fmt::to_hex(&self.digest_prefix, false)) .field("computed_digest", &if let Some(ref hash) = self.computed_digest { Some(crate::fmt::to_hex(&hash[..], false)) } else { None }) .field("level", &self.level) .field("mpis", &self.mpis) .finish() } } impl PartialEq for Signature4 { /// This method tests for self and other values to be equal, and /// is used by ==. /// /// This method compares the serialized version of the two /// packets. Thus, the computed values are ignored ([`level`], /// [`computed_digest`]). /// /// Note: because this function also compares the unhashed /// subpacket area, it is possible for a malicious party to take /// valid signatures, add subpackets to the unhashed area, /// yielding valid but distinct signatures. If you want to ignore /// the unhashed area, you should instead use the /// [`Signature4::normalized_eq`] method. /// /// [`level`]: #method.level /// [`computed_digest`]: #method.computed_digest /// [`Signature4::normalized_eq`]: #method.normalized_eq fn eq(&self, other: &Signature4) -> bool { self.mpis == other.mpis && self.fields == other.fields && self.digest_prefix == other.digest_prefix } } impl Eq for Signature4 {} impl std::hash::Hash for Signature4 { fn hash<H: std::hash::Hasher>(&self, state: &mut H) { use std::hash::Hash as StdHash; StdHash::hash(&self.mpis, state); StdHash::hash(&self.fields, state); self.digest_prefix.hash(state); } } impl Signature4 { /// Creates a new signature packet. /// /// If you want to sign something, consider using the [`SignatureBuilder`] /// interface. /// /// [`SignatureBuilder`]: struct.SignatureBuilder.html pub fn new(typ: SignatureType, pk_algo: PublicKeyAlgorithm, hash_algo: HashAlgorithm, hashed_area: SubpacketArea, unhashed_area: SubpacketArea, digest_prefix: [u8; 2], mpis: mpi::Signature) -> Self { Signature4 { common: Default::default(), fields: SignatureFields { version: 4, typ, pk_algo, hash_algo, subpackets: SubpacketAreas::new(hashed_area, unhashed_area), }, digest_prefix, mpis, computed_digest: None, level: 0, } } /// Gets the public key algorithm. // SigantureFields::pk_algo is private, because we don't want it // available on SignatureBuilder, which also derefs to // &SignatureFields. pub fn pk_algo(&self) -> PublicKeyAlgorithm { self.fields.pk_algo() } /// Gets the hash prefix. pub fn digest_prefix(&self) -> &[u8; 2] { &self.digest_prefix } /// Sets the hash prefix. #[allow(dead_code)] pub(crate) fn set_digest_prefix(&mut self, prefix: [u8; 2]) -> [u8; 2] { ::std::mem::replace(&mut self.digest_prefix, prefix) } /// Gets the signature packet's MPIs. pub fn mpis(&self) -> &mpi::Signature { &self.mpis } /// Sets the signature packet's MPIs. #[allow(dead_code)] pub(crate) fn set_mpis(&mut self, mpis: mpi::Signature) -> mpi::Signature { ::std::mem::replace(&mut self.mpis, mpis) } /// Gets the computed hash value. /// /// This is set by the [`PacketParser`] when parsing the message. /// /// [`PacketParser`]: ../../parse/struct.PacketParser.html pub fn computed_digest(&self) -> Option<&[u8]> { self.computed_digest.as_ref().map(|d| &d[..]) } /// Sets the computed hash value. pub(crate) fn set_computed_digest(&mut self, hash: Option<Vec<u8>>) -> Option<Vec<u8>> { ::std::mem::replace(&mut self.computed_digest, hash) } /// Gets the signature level. /// /// A level of 0 indicates that the signature is directly over the /// data, a level of 1 means that the signature is a notarization /// over all level 0 signatures and the data, and so on. pub fn level(&self) -> usize { self.level } /// Sets the signature level. /// /// A level of 0 indicates that the signature is directly over the /// data, a level of 1 means that the signature is a notarization /// over all level 0 signatures and the data, and so on. pub(crate) fn set_level(&mut self, level: usize) -> usize { ::std::mem::replace(&mut self.level, level) } /// Returns whether or not this signature should be exported. /// /// This checks whether the [`Exportable Certification`] subpacket /// is absent or present and 1, and that the signature does not /// include any sensitive [`Revocation Key`] (designated revokers) /// subpackets. /// /// [`Exportable Certification`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.11 /// [`Revocation Key`]: https://tools.ietf.org/html/rfc4880#section-5.2.3.15 pub fn exportable(&self) -> Result<()> { if ! self.exportable_certification().unwrap_or(true) { return Err(Error::InvalidOperation( "Cannot export non-exportable certification".into()).into()); } if self.revocation_keys().any(|r| r.sensitive()) { return Err(Error::InvalidOperation( "Cannot export signature with sensitive designated revoker" .into()).into()); } Ok(()) } } impl crate::packet::Signature { /// Returns the value of any Issuer and Issuer Fingerprint subpackets. /// /// The [Issuer subpacket] and [Issuer Fingerprint subpacket] are /// used when processing a signature to identify which certificate /// created the signature. Since this information is /// self-authenticating (the act of validating the signature /// authenticates the subpacket), it is typically stored in the /// unhashed subpacket area. /// /// [Issuer subpacket]: https://tools.ietf.org/html/rfc4880#section-5.2.3.5 /// [Issuer Fingerprint subpacket]: https://www.ietf.org/id/draft-ietf-openpgp-rfc4880bis-09.html#section-5.2.3.28 /// /// This function returns all instances of the Issuer subpacket /// and the Issuer Fingerprint subpacket in both the hashed /// subpacket area and the unhashed subpacket area. /// /// The issuers are sorted so that the `Fingerprints` come before /// `KeyID`s. The `Fingerprint`s and `KeyID`s are not further /// sorted, but are returned in the order that they are /// encountered. pub fn get_issuers(&self) -> Vec<crate::KeyHandle> { use crate::packet::signature::subpacket:: SubpacketValue; let mut issuers: Vec<_> = self.hashed_area().iter() .chain(self.unhashed_area().iter()) .filter_map(|subpacket| { match subpacket.value() { SubpacketValue::Issuer(i) => Some(i.into()), SubpacketValue::IssuerFingerprint(i) => Some(i.into()), _ => None, } }) .collect(); // Sort the issuers so that the fingerprints come first. issuers.sort_by(|a, b| { use crate::KeyHandle::*; use std::cmp::Ordering::*; match (a, b) { (Fingerprint(_), Fingerprint(_)) => Equal, (KeyID(_), Fingerprint(_)) => Greater, (Fingerprint(_), KeyID(_)) => Less, (KeyID(_), KeyID(_)) => Equal, } }); issuers } /// Compares Signatures ignoring the unhashed subpacket area. /// /// This comparison function ignores the unhashed subpacket area /// when comparing two signatures. This prevents a malicious /// party from taking valid signatures, adding subpackets to the /// unhashed area, and deriving valid but distinct signatures, /// which could be used to perform a denial of service attack. /// For instance, an attacker could create a lot of signatures, /// which need to be validated. Ignoring the unhashed subpackets /// means that we can deduplicate signatures using this predicate. /// /// # Examples /// /// ``` /// use sequoia_openpgp as openpgp; /// use openpgp::cert::prelude::*; /// use openpgp::packet::prelude::*; /// use openpgp::packet::signature::subpacket::{Subpacket, SubpacketValue}; /// use openpgp::policy::StandardPolicy; /// use openpgp::types::SignatureType; /// use openpgp::types::Features; /// /// # fn main() -> openpgp::Result<()> { /// let p = &StandardPolicy::new(); /// /// let (cert, _) = CertBuilder::new().generate()?; /// /// let orig = cert.with_policy(p, None)?.direct_key_signature()?; /// /// // Add an inconspicuous subpacket to the unhashed area. /// let sb = Subpacket::new(SubpacketValue::Features(Features::empty()), false)?; /// let mut modified = orig.clone(); /// modified.unhashed_area_mut().add(sb); /// /// // We modified the signature, but the signature is still valid. /// modified.verify_direct_key(cert.primary_key().key(), cert.primary_key().key()); /// /// // PartialEq considers the packets to not be equal... /// assert!(orig != &modified); /// // ... but normalized_eq does. /// assert!(orig.normalized_eq(&modified)); /// # Ok(()) /// # } /// ``` pub fn normalized_eq(&self, other: &Signature) -> bool { self.mpis() == other.mpis() && self.version() == other.version() && self.typ() == other.typ() && self.pk_algo() == other.pk_algo() && self.hash_algo() == other.hash_algo() && self.hashed_area() == other.hashed_area() && self.digest_prefix() == other.digest_prefix() } /// Normalizes the signature. /// /// This function normalizes the *unhashed* signature subpackets. /// It removes all but the following self-authenticating /// subpackets: /// /// - `SubpacketValue::Issuer` /// - `SubpacketValue::IssuerFingerprint` /// - `SubpacketValue::EmbeddedSignature` /// /// Note: the retained subpackets are not checked for validity. pub fn normalize(&self) -> Self { use crate::packet::signature::subpacket::SubpacketTag::*; let mut sig = self.clone(); { let area = sig.unhashed_area_mut(); area.clear(); for spkt in self.unhashed_area().iter() .filter(|s| s.tag() == Issuer || s.tag() == IssuerFingerprint || s.tag() == EmbeddedSignature) { area.add(spkt.clone()) .expect("it did fit into the old area"); } } sig } } /// Verification-related functionality. /// /// <a name="verification-functions"></a> impl Signature { /// Verifies the signature against `hash`. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature and checks that the key predates the /// signature. Further constraints on the signature, like /// creation and expiration time, or signature revocations must be /// checked by the caller. /// /// Likewise, this function does not check whether `key` can made /// valid signatures; it is up to the caller to make sure the key /// is not revoked, not expired, has a valid self-signature, has a /// subkey binding signature (if appropriate), has the signing /// capability, etc. pub fn verify_digest<P, R, D>(&self, key: &Key<P, R>, digest: D) -> Result<()> where P: key::KeyParts, R: key::KeyRole, D: AsRef<[u8]>, { if let Some(creation_time) = self.signature_creation_time() { if creation_time < key.creation_time() { return Err(Error::BadSignature( format!("Signature (created {:?}) predates key ({:?})", creation_time, key.creation_time())).into()); } } else { return Err(Error::BadSignature( "Signature has no creation time subpacket".into()).into()); } key.verify(self, digest.as_ref()) } /// Verifies the signature over text or binary documents using /// `key`. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `key` can make /// valid signatures; it is up to the caller to make sure the key /// is not revoked, not expired, has a valid self-signature, has a /// subkey binding signature (if appropriate), has the signing /// capability, etc. pub fn verify<P, R>(&self, key: &Key<P, R>) -> Result<()> where P: key::KeyParts, R: key::KeyRole, { if !(self.typ() == SignatureType::Binary || self.typ() == SignatureType::Text) { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } if let Some(ref hash) = self.computed_digest { self.verify_digest(key, hash) } else { Err(Error::BadSignature("Hash not computed.".to_string()).into()) } } /// Verifies the standalone signature using `key`. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `key` can make /// valid signatures; it is up to the caller to make sure the key /// is not revoked, not expired, has a valid self-signature, has a /// subkey binding signature (if appropriate), has the signing /// capability, etc. pub fn verify_standalone<P, R>(&self, key: &Key<P, R>) -> Result<()> where P: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::Standalone { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } // Standalone signatures are like binary-signatures over the // zero-sized string. let digest = Signature::hash_standalone(self)?; self.verify_digest(key, &digest[..]) } /// Verifies the timestamp signature using `key`. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `key` can make /// valid signatures; it is up to the caller to make sure the key /// is not revoked, not expired, has a valid self-signature, has a /// subkey binding signature (if appropriate), has the signing /// capability, etc. pub fn verify_timestamp<P, R>(&self, key: &Key<P, R>) -> Result<()> where P: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::Timestamp { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } // Timestamp signatures are like binary-signatures over the // zero-sized string. let digest = Signature::hash_timestamp(self)?; self.verify_digest(key, &digest[..]) } /// Verifies the direct key signature. /// /// `self` is the direct key signature, `signer` is the /// key that allegedly made the signature, and `pk` is the primary /// key. /// /// For a self-signature, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_direct_key<P, Q, R>(&self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::DirectKey { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_direct_key(self, pk)?; self.verify_digest(signer, &hash[..]) } /// Verifies the primary key revocation certificate. /// /// `self` is the primary key revocation certificate, `signer` is /// the key that allegedly made the signature, and `pk` is the /// primary key, /// /// For a self-signature, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_primary_key_revocation<P, Q, R>(&self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::KeyRevocation { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_direct_key(self, pk)?; self.verify_digest(signer, &hash[..]) } /// Verifies the subkey binding. /// /// `self` is the subkey key binding signature, `signer` is the /// key that allegedly made the signature, `pk` is the primary /// key, and `subkey` is the subkey. /// /// For a self-signature, `signer` and `pk` will be the same. /// /// If the signature indicates that this is a `Signing` capable /// subkey, then the back signature is also verified. If it is /// missing or can't be verified, then this function returns /// false. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_subkey_binding<P, Q, R, S>( &self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>, subkey: &Key<S, key::SubordinateRole>) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, S: key::KeyParts, { if self.typ() != SignatureType::SubkeyBinding { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_subkey_binding(self, pk, subkey)?; self.verify_digest(signer, &hash[..])?; // The signature is good, but we may still need to verify the // back sig. if self.key_flags().map(|kf| kf.for_signing()).unwrap_or(false) { if let Some(backsig) = self.embedded_signature() { backsig.verify_primary_key_binding(pk, subkey) } else { Err(Error::BadSignature( "Primary key binding signature missing".into()).into()) } } else { // No backsig required. Ok(()) } } /// Verifies the primary key binding. /// /// `self` is the primary key binding signature, `pk` is the /// primary key, and `subkey` is the subkey. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `subkey` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_primary_key_binding<P, Q>( &self, pk: &Key<P, key::PrimaryRole>, subkey: &Key<Q, key::SubordinateRole>) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, { if self.typ() != SignatureType::PrimaryKeyBinding { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_primary_key_binding(self, pk, subkey)?; self.verify_digest(subkey, &hash[..]) } /// Verifies the subkey revocation. /// /// `self` is the subkey key revocation certificate, `signer` is /// the key that allegedly made the signature, `pk` is the primary /// key, and `subkey` is the subkey. /// /// For a self-revocation, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_subkey_revocation<P, Q, R, S>( &self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>, subkey: &Key<S, key::SubordinateRole>) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, S: key::KeyParts, { if self.typ() != SignatureType::SubkeyRevocation { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_subkey_binding(self, pk, subkey)?; self.verify_digest(signer, &hash[..]) } /// Verifies the user id binding. /// /// `self` is the user id binding signature, `signer` is the key /// that allegedly made the signature, `pk` is the primary key, /// and `userid` is the user id. /// /// For a self-signature, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_userid_binding<P, Q, R>(&self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>, userid: &UserID) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, { if !(self.typ() == SignatureType::GenericCertification || self.typ() == SignatureType::PersonaCertification || self.typ() == SignatureType::CasualCertification || self.typ() == SignatureType::PositiveCertification) { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_userid_binding(self, pk, userid)?; self.verify_digest(signer, &hash[..]) } /// Verifies the user id revocation certificate. /// /// `self` is the revocation certificate, `signer` is the key /// that allegedly made the signature, `pk` is the primary key, /// and `userid` is the user id. /// /// For a self-signature, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_userid_revocation<P, Q, R>(&self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>, userid: &UserID) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::CertificationRevocation { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_userid_binding(self, pk, userid)?; self.verify_digest(signer, &hash[..]) } /// Verifies the user attribute binding. /// /// `self` is the user attribute binding signature, `signer` is /// the key that allegedly made the signature, `pk` is the primary /// key, and `ua` is the user attribute. /// /// For a self-signature, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_user_attribute_binding<P, Q, R>(&self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>, ua: &UserAttribute) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, { if !(self.typ() == SignatureType::GenericCertification || self.typ() == SignatureType::PersonaCertification || self.typ() == SignatureType::CasualCertification || self.typ() == SignatureType::PositiveCertification) { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_user_attribute_binding(self, pk, ua)?; self.verify_digest(signer, &hash[..]) } /// Verifies the user attribute revocation certificate. /// /// `self` is the user attribute binding signature, `signer` is /// the key that allegedly made the signature, `pk` is the primary /// key, and `ua` is the user attribute. /// /// For a self-signature, `signer` and `pk` will be the same. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_user_attribute_revocation<P, Q, R>( &self, signer: &Key<P, R>, pk: &Key<Q, key::PrimaryRole>, ua: &UserAttribute) -> Result<()> where P: key::KeyParts, Q: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::CertificationRevocation { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } let hash = Signature::hash_user_attribute_binding(self, pk, ua)?; self.verify_digest(signer, &hash[..]) } /// Verifies a signature of a message. /// /// `self` is the message signature, `signer` is /// the key that allegedly made the signature and `msg` is the message. /// /// This function is for short messages, if you want to verify larger files /// use `Verifier`. /// /// Note: Due to limited context, this only verifies the /// cryptographic signature, checks the signature's type, and /// checks that the key predates the signature. Further /// constraints on the signature, like creation and expiration /// time, or signature revocations must be checked by the caller. /// /// Likewise, this function does not check whether `signer` can /// made valid signatures; it is up to the caller to make sure the /// key is not revoked, not expired, has a valid self-signature, /// has a subkey binding signature (if appropriate), has the /// signing capability, etc. pub fn verify_message<M, P, R>(&self, signer: &Key<P, R>, msg: M) -> Result<()> where M: AsRef<[u8]>, P: key::KeyParts, R: key::KeyRole, { if self.typ() != SignatureType::Binary && self.typ() != SignatureType::Text { return Err(Error::UnsupportedSignatureType(self.typ()).into()); } // Compute the digest. let mut hash = self.hash_algo().context()?; let mut digest = vec![0u8; hash.digest_size()]; hash.update(msg.as_ref()); self.hash(&mut hash); hash.digest(&mut digest); self.verify_digest(signer, &digest[..]) } } impl From<Signature4> for Packet { fn from(s: Signature4) -> Self { Packet::Signature(s.into()) } } impl From<Signature4> for super::Signature { fn from(s: Signature4) -> Self { super::Signature::V4(s) } } #[cfg(any(test, feature = "quickcheck"))] impl ArbitraryBounded for super::Signature { fn arbitrary_bounded<G: Gen>(g: &mut G, depth: usize) -> Self { Signature4::arbitrary_bounded(g, depth).into() } } #[cfg(any(test, feature = "quickcheck"))] impl_arbitrary_with_bound!(super::Signature); #[cfg(any(test, feature = "quickcheck"))] impl ArbitraryBounded for Signature4 { fn arbitrary_bounded<G: Gen>(g: &mut G, depth: usize) -> Self { use mpi::MPI; use PublicKeyAlgorithm::*; let fields = SignatureFields::arbitrary_bounded(g, depth); #[allow(deprecated)] let mpis = match fields.pk_algo() { RSAEncryptSign | RSASign => mpi::Signature::RSA { s: MPI::arbitrary(g), }, DSA => mpi::Signature::DSA { r: MPI::arbitrary(g), s: MPI::arbitrary(g), }, EdDSA => mpi::Signature::EdDSA { r: MPI::arbitrary(g), s: MPI::arbitrary(g), }, ECDSA => mpi::Signature::ECDSA { r: MPI::arbitrary(g), s: MPI::arbitrary(g), }, _ => unreachable!(), }; Signature4 { common: Arbitrary::arbitrary(g), fields, digest_prefix: [Arbitrary::arbitrary(g), Arbitrary::arbitrary(g)], mpis, computed_digest: None, level: 0, } } } #[cfg(any(test, feature = "quickcheck"))] impl_arbitrary_with_bound!(Signature4); #[cfg(test)] mod test { use super::*; use crate::KeyID; use crate::cert::prelude::*; use crate::crypto; use crate::parse::Parse; use crate::packet::Key; use crate::packet::key::Key4; use crate::types::Curve; use crate::policy::StandardPolicy as P; #[cfg(feature = "compression-deflate")] #[test] fn signature_verification_test() { use super::*; use crate::Cert; use crate::parse::{PacketParserResult, PacketParser}; struct Test<'a> { key: &'a str, data: &'a str, good: usize, }; let tests = [ Test { key: &"neal.pgp"[..], data: &"signed-1.gpg"[..], good: 1, }, Test { key: &"neal.pgp"[..], data: &"signed-1-sha1-neal.gpg"[..], good: 1, }, Test { key: &"testy.pgp"[..], data: &"signed-1-sha256-testy.gpg"[..], good: 1, }, Test { key: &"dennis-simon-anton.pgp"[..], data: &"signed-1-dsa.pgp"[..], good: 1, }, Test { key: &"erika-corinna-daniela-simone-antonia-nistp256.pgp"[..], data: &"signed-1-ecdsa-nistp256.pgp"[..], good: 1, }, Test { key: &"erika-corinna-daniela-simone-antonia-nistp384.pgp"[..], data: &"signed-1-ecdsa-nistp384.pgp"[..], good: 1, }, Test { key: &"erika-corinna-daniela-simone-antonia-nistp521.pgp"[..], data: &"signed-1-ecdsa-nistp521.pgp"[..], good: 1, }, Test { key: &"emmelie-dorothea-dina-samantha-awina-ed25519.pgp"[..], data: &"signed-1-eddsa-ed25519.pgp"[..], good: 1, }, Test { key: &"emmelie-dorothea-dina-samantha-awina-ed25519.pgp"[..], data: &"signed-twice-by-ed25519.pgp"[..], good: 2, }, Test { key: "neal.pgp", data: "signed-1-notarized-by-ed25519.pgp", good: 1, }, Test { key: "emmelie-dorothea-dina-samantha-awina-ed25519.pgp", data: "signed-1-notarized-by-ed25519.pgp", good: 1, }, // Check with the wrong key. Test { key: &"neal.pgp"[..], data: &"signed-1-sha256-testy.gpg"[..], good: 0, }, Test { key: &"neal.pgp"[..], data: &"signed-2-partial-body.gpg"[..], good: 1, }, ]; for test in tests.iter() { eprintln!("{}, expect {} good signatures:", test.data, test.good); let cert = Cert::from_bytes(crate::tests::key(test.key)).unwrap(); let mut good = 0; let mut ppr = PacketParser::from_bytes( crate::tests::message(test.data)).unwrap(); while let PacketParserResult::Some(pp) = ppr { if let Packet::Signature(ref sig) = pp.packet { let result = sig.verify(cert.primary_key().key()) .map(|_| true).unwrap_or(false); eprintln!(" Primary {:?}: {:?}", cert.fingerprint(), result); if result { good += 1; } for sk in cert.subkeys() { let result = sig.verify(sk.key()) .map(|_| true).unwrap_or(false); eprintln!(" Subkey {:?}: {:?}", sk.key().fingerprint(), result); if result { good += 1; } } } // Get the next packet. ppr = pp.recurse().unwrap().1; } assert_eq!(good, test.good, "Signature verification failed."); } } #[test] fn signature_level() { use crate::PacketPile; let p = PacketPile::from_bytes( crate::tests::message("signed-1-notarized-by-ed25519.pgp")).unwrap() .into_children().collect::<Vec<Packet>>(); if let Packet::Signature(ref sig) = &p[3] { assert_eq!(sig.level(), 0); } else { panic!("expected signature") } if let Packet::Signature(ref sig) = &p[4] { assert_eq!(sig.level(), 1); } else { panic!("expected signature") } } #[test] fn sign_verify() { let hash_algo = HashAlgorithm::SHA512; let mut hash = vec![0; hash_algo.context().unwrap().digest_size()]; crypto::random(&mut hash); for key in &[ "testy-private.pgp", "dennis-simon-anton-private.pgp", "erika-corinna-daniela-simone-antonia-nistp256-private.pgp", "erika-corinna-daniela-simone-antonia-nistp384-private.pgp", "erika-corinna-daniela-simone-antonia-nistp521-private.pgp", "emmelie-dorothea-dina-samantha-awina-ed25519-private.pgp", ] { let cert = Cert::from_bytes(crate::tests::key(key)).unwrap(); let mut pair = cert.primary_key().key().clone() .parts_into_secret().unwrap() .into_keypair() .expect("secret key is encrypted/missing"); let sig = SignatureBuilder::new(SignatureType::Binary); let hash = hash_algo.context().unwrap(); // Make signature. let sig = sig.sign_hash(&mut pair, hash).unwrap(); // Good signature. let mut hash = hash_algo.context().unwrap(); sig.hash(&mut hash); let mut digest = vec![0u8; hash.digest_size()]; hash.digest(&mut digest); sig.verify_digest(pair.public(), &digest[..]).unwrap(); // Bad signature. digest[0] ^= 0xff; sig.verify_digest(pair.public(), &digest[..]).unwrap_err(); } } #[test] fn sign_message() { use crate::types::Curve; let key: Key<key::SecretParts, key::PrimaryRole> = Key4::generate_ecc(true, Curve::Ed25519) .unwrap().into(); let msg = b"Hello, World"; let mut pair = key.into_keypair().unwrap(); let sig = SignatureBuilder::new(SignatureType::Binary) .sign_message(&mut pair, msg).unwrap(); sig.verify_message(pair.public(), msg).unwrap(); } #[test] fn verify_message() { let cert = Cert::from_bytes(crate::tests::key( "emmelie-dorothea-dina-samantha-awina-ed25519.pgp")).unwrap(); let msg = crate::tests::manifesto(); let p = Packet::from_bytes( crate::tests::message("a-cypherpunks-manifesto.txt.ed25519.sig")) .unwrap(); let sig = if let Packet::Signature(s) = p { s } else { panic!("Expected a Signature, got: {:?}", p); }; sig.verify_message(cert.primary_key().key(), &msg[..]).unwrap(); } #[test] fn sign_with_short_ed25519_secret_key() { // 20 byte sec key let secret_key = [ 0x0,0x0, 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, 0x1,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2, 0x1,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x2 ]; let key: key::SecretKey = Key4::import_secret_ed25519(&secret_key, None) .unwrap().into(); let mut pair = key.into_keypair().unwrap(); let msg = b"Hello, World"; let mut hash = HashAlgorithm::SHA256.context().unwrap(); hash.update(&msg[..]); SignatureBuilder::new(SignatureType::Text) .sign_hash(&mut pair, hash).unwrap(); } #[test] fn verify_gpg_3rd_party_cert() { use crate::Cert; let p = &P::new(); let test1 = Cert::from_bytes( crate::tests::key("test1-certification-key.pgp")).unwrap(); let cert_key1 = test1.keys().with_policy(p, None) .for_certification() .nth(0) .map(|ka| ka.key()) .unwrap(); let test2 = Cert::from_bytes( crate::tests::key("test2-signed-by-test1.pgp")).unwrap(); let uid = test2.userids().with_policy(p, None).nth(0).unwrap(); let cert = &uid.certifications()[0]; cert.verify_userid_binding(cert_key1, test2.primary_key().key(), uid.userid()).unwrap(); } #[test] fn normalize() { use crate::Fingerprint; use crate::packet::signature::subpacket::*; let key : key::SecretKey = Key4::generate_ecc(true, Curve::Ed25519).unwrap().into(); let mut pair = key.into_keypair().unwrap(); let msg = b"Hello, World"; let mut hash = HashAlgorithm::SHA256.context().unwrap(); hash.update(&msg[..]); let fp = Fingerprint::from_bytes(b"bbbbbbbbbbbbbbbbbbbb"); let keyid = KeyID::from(&fp); // First, make sure any superfluous subpackets are removed, // yet the Issuer, IssuerFingerprint and EmbeddedSignature // ones are kept. let mut builder = SignatureBuilder::new(SignatureType::Text); builder.unhashed_area_mut().add(Subpacket::new( SubpacketValue::IssuerFingerprint(fp.clone()), false).unwrap()) .unwrap(); builder.unhashed_area_mut().add(Subpacket::new( SubpacketValue::Issuer(keyid.clone()), false).unwrap()) .unwrap(); // This subpacket does not belong there, and should be // removed. builder.unhashed_area_mut().add(Subpacket::new( SubpacketValue::PreferredSymmetricAlgorithms(Vec::new()), false).unwrap()).unwrap(); // Build and add an embedded sig. let embedded_sig = SignatureBuilder::new(SignatureType::PrimaryKeyBinding) .sign_hash(&mut pair, hash.clone()).unwrap(); builder.unhashed_area_mut().add(Subpacket::new( SubpacketValue::EmbeddedSignature(embedded_sig.into()), false) .unwrap()).unwrap(); let sig = builder.sign_hash(&mut pair, hash.clone()).unwrap().normalize(); assert_eq!(sig.unhashed_area().iter().count(), 3); assert_eq!(*sig.unhashed_area().iter().nth(0).unwrap(), Subpacket::new(SubpacketValue::Issuer(keyid.clone()), false).unwrap()); assert_eq!(sig.unhashed_area().iter().nth(1).unwrap().tag(), SubpacketTag::EmbeddedSignature); assert_eq!(*sig.unhashed_area().iter().nth(2).unwrap(), Subpacket::new(SubpacketValue::IssuerFingerprint(fp.clone()), false).unwrap()); } #[test] fn standalone_signature_roundtrip() { let key : key::SecretKey = Key4::generate_ecc(true, Curve::Ed25519).unwrap().into(); let mut pair = key.into_keypair().unwrap(); let sig = SignatureBuilder::new(SignatureType::Standalone) .sign_standalone(&mut pair) .unwrap(); sig.verify_standalone(pair.public()).unwrap(); } #[test] fn timestamp_signature() { let alpha = Cert::from_bytes(crate::tests::file( "contrib/gnupg/keys/alpha.pgp")).unwrap(); let p = Packet::from_bytes(crate::tests::file( "contrib/gnupg/timestamp-signature-by-alice.asc")).unwrap(); if let Packet::Signature(sig) = p { let digest = Signature::hash_standalone(&sig).unwrap(); eprintln!("{}", crate::fmt::hex::encode(&digest)); sig.verify_timestamp(alpha.primary_key().key()).unwrap(); } else { panic!("expected a signature packet"); } } #[test] fn timestamp_signature_roundtrip() { let key : key::SecretKey = Key4::generate_ecc(true, Curve::Ed25519).unwrap().into(); let mut pair = key.into_keypair().unwrap(); let sig = SignatureBuilder::new(SignatureType::Timestamp) .sign_timestamp(&mut pair) .unwrap(); sig.verify_timestamp(pair.public()).unwrap(); } #[test] fn get_issuers_prefers_fingerprints() -> Result<()> { use crate::KeyHandle; for f in [ // This has Fingerprint in the hashed, Issuer in the // unhashed area. "messages/sig.gpg", // This has [Issuer, Fingerprint] in the hashed area. "contrib/gnupg/timestamp-signature-by-alice.asc", ].iter() { let p = Packet::from_bytes(crate::tests::file(f))?; if let Packet::Signature(sig) = p { let issuers = sig.get_issuers(); assert_match!(KeyHandle::Fingerprint(_) = &issuers[0]); assert_match!(KeyHandle::KeyID(_) = &issuers[1]); } else { panic!("expected a signature packet"); } } Ok(()) } }