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
// Copyright 2015 Brian Smith.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

use crate::{der, equal, Error};
use ring::signature;

/// X.509 certificates and related items that are signed are almost always
/// encoded in the format "tbs||signatureAlgorithm||signature". This structure
/// captures this pattern.
pub struct SignedData<'a> {
    /// The signed data. This would be `tbsCertificate` in the case of an X.509
    /// certificate, `tbsResponseData` in the case of an OCSP response, and the
    /// data nested in the `digitally-signed` construct for TLS 1.2 signed
    /// data.
    data: untrusted::Input<'a>,

    /// The value of the `AlgorithmIdentifier`. This would be
    /// `signatureAlgorithm` in the case of an X.509 certificate or OCSP
    /// response. This would have to be synthesized in the case of TLS 1.2
    /// signed data, since TLS does not identify algorithms by ASN.1 OIDs.
    pub(crate) algorithm: untrusted::Input<'a>,

    /// The value of the signature. This would be `signature` in an X.509
    /// certificate or OCSP response. This would be the value of
    /// `DigitallySigned.signature` for TLS 1.2 signed data.
    signature: untrusted::Input<'a>,
}

/// Parses the concatenation of "tbs||signatureAlgorithm||signature" that
/// is common in the X.509 certificate and OCSP response syntaxes.
///
/// X.509 Certificates (RFC 5280) look like this:
///
/// ```ASN.1
/// Certificate (SEQUENCE) {
///     tbsCertificate TBSCertificate,
///     signatureAlgorithm AlgorithmIdentifier,
///     signatureValue BIT STRING
/// }
/// ```
///
/// OCSP responses (RFC 6960) look like this:
/// ```ASN.1
/// BasicOCSPResponse {
///     tbsResponseData ResponseData,
///     signatureAlgorithm AlgorithmIdentifier,
///     signature BIT STRING,
///     certs [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL
/// }
/// ```
///
/// Note that this function does NOT parse the outermost `SEQUENCE` or the
/// `certs` value.
///
/// The return value's first component is the contents of
/// `tbsCertificate`/`tbsResponseData`; the second component is a `SignedData`
/// structure that can be passed to `verify_signed_data`.
pub(crate) fn parse_signed_data<'a>(
    der: &mut untrusted::Reader<'a>,
) -> Result<(untrusted::Input<'a>, SignedData<'a>), Error> {
    let (data, tbs) =
        der.read_partial(|input| der::expect_tag_and_get_value(input, der::Tag::Sequence))?;
    let algorithm = der::expect_tag_and_get_value(der, der::Tag::Sequence)?;
    let signature = der::bit_string_with_no_unused_bits(der)?;

    Ok((
        tbs,
        SignedData {
            data,
            algorithm,
            signature,
        },
    ))
}

/// Verify `signed_data` using the public key in the DER-encoded
/// SubjectPublicKeyInfo `spki` using one of the algorithms in
/// `supported_algorithms`.
///
/// The algorithm is chosen based on the algorithm information encoded in the
/// algorithm identifiers in `public_key` and `signed_data.algorithm`. The
/// ordering of the algorithms in `supported_algorithms` does not really matter,
/// but generally more common algorithms should go first, as it is scanned
/// linearly for matches.
pub(crate) fn verify_signed_data(
    supported_algorithms: &[&SignatureAlgorithm],
    spki_value: untrusted::Input,
    signed_data: &SignedData,
) -> Result<(), Error> {
    // We need to verify the signature in `signed_data` using the public key
    // in `public_key`. In order to know which *ring* signature verification
    // algorithm to use, we need to know the public key algorithm (ECDSA,
    // RSA PKCS#1, etc.), the curve (if applicable), and the digest algorithm.
    // `signed_data` identifies only the public key algorithm and the digest
    // algorithm, and `public_key` identifies only the public key algorithm and
    // the curve (if any). Thus, we have to combine information from both
    // inputs to figure out which `ring::signature::VerificationAlgorithm` to
    // use to verify the signature.
    //
    // This is all further complicated by the fact that we don't have any
    // implicit knowledge about any algorithms or identifiers, since all of
    // that information is encoded in `supported_algorithms.` In particular, we
    // avoid hard-coding any of that information so that (link-time) dead code
    // elimination will work effectively in eliminating code for unused
    // algorithms.

    // Parse the signature.
    //
    let mut found_signature_alg_match = false;
    for supported_alg in supported_algorithms.iter().filter(|alg| {
        alg.signature_alg_id
            .matches_algorithm_id_value(signed_data.algorithm)
    }) {
        match verify_signature(
            supported_alg,
            spki_value,
            signed_data.data,
            signed_data.signature,
        ) {
            Err(Error::UnsupportedSignatureAlgorithmForPublicKey) => {
                found_signature_alg_match = true;
                continue;
            }
            result => {
                return result;
            }
        }
    }

    if found_signature_alg_match {
        Err(Error::UnsupportedSignatureAlgorithmForPublicKey)
    } else {
        Err(Error::UnsupportedSignatureAlgorithm)
    }
}

pub(crate) fn verify_signature(
    signature_alg: &SignatureAlgorithm,
    spki_value: untrusted::Input,
    msg: untrusted::Input,
    signature: untrusted::Input,
) -> Result<(), Error> {
    let spki = parse_spki_value(spki_value)?;
    if !signature_alg
        .public_key_alg_id
        .matches_algorithm_id_value(spki.algorithm_id_value)
    {
        return Err(Error::UnsupportedSignatureAlgorithmForPublicKey);
    }
    signature::UnparsedPublicKey::new(
        signature_alg.verification_alg,
        spki.key_value.as_slice_less_safe(),
    )
    .verify(msg.as_slice_less_safe(), signature.as_slice_less_safe())
    .map_err(|_| Error::InvalidSignatureForPublicKey)
}

struct SubjectPublicKeyInfo<'a> {
    algorithm_id_value: untrusted::Input<'a>,
    key_value: untrusted::Input<'a>,
}

// Parse the public key into an algorithm OID, an optional curve OID, and the
// key value. The caller needs to check whether these match the
// `PublicKeyAlgorithm` for the `SignatureAlgorithm` that is matched when
// parsing the signature.
fn parse_spki_value(input: untrusted::Input) -> Result<SubjectPublicKeyInfo, Error> {
    input.read_all(Error::BadDer, |input| {
        let algorithm_id_value = der::expect_tag_and_get_value(input, der::Tag::Sequence)?;
        let key_value = der::bit_string_with_no_unused_bits(input)?;
        Ok(SubjectPublicKeyInfo {
            algorithm_id_value,
            key_value,
        })
    })
}

/// A signature algorithm.
pub struct SignatureAlgorithm {
    public_key_alg_id: AlgorithmIdentifier,
    signature_alg_id: AlgorithmIdentifier,
    verification_alg: &'static dyn signature::VerificationAlgorithm,
}

/// ECDSA signatures using the P-256 curve and SHA-256.
pub static ECDSA_P256_SHA256: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: ECDSA_P256,
    signature_alg_id: ECDSA_SHA256,
    verification_alg: &signature::ECDSA_P256_SHA256_ASN1,
};

/// ECDSA signatures using the P-256 curve and SHA-384. Deprecated.
pub static ECDSA_P256_SHA384: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: ECDSA_P256,
    signature_alg_id: ECDSA_SHA384,
    verification_alg: &signature::ECDSA_P256_SHA384_ASN1,
};

/// ECDSA signatures using the P-384 curve and SHA-256. Deprecated.
pub static ECDSA_P384_SHA256: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: ECDSA_P384,
    signature_alg_id: ECDSA_SHA256,
    verification_alg: &signature::ECDSA_P384_SHA256_ASN1,
};

/// ECDSA signatures using the P-384 curve and SHA-384.
pub static ECDSA_P384_SHA384: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: ECDSA_P384,
    signature_alg_id: ECDSA_SHA384,
    verification_alg: &signature::ECDSA_P384_SHA384_ASN1,
};

/// RSA PKCS#1 1.5 signatures using SHA-256 for keys of 2048-8192 bits.
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PKCS1_2048_8192_SHA256: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PKCS1_SHA256,
    verification_alg: &signature::RSA_PKCS1_2048_8192_SHA256,
};

/// RSA PKCS#1 1.5 signatures using SHA-384 for keys of 2048-8192 bits.
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PKCS1_2048_8192_SHA384: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PKCS1_SHA384,
    verification_alg: &signature::RSA_PKCS1_2048_8192_SHA384,
};

/// RSA PKCS#1 1.5 signatures using SHA-512 for keys of 2048-8192 bits.
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PKCS1_2048_8192_SHA512: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PKCS1_SHA512,
    verification_alg: &signature::RSA_PKCS1_2048_8192_SHA512,
};

/// RSA PKCS#1 1.5 signatures using SHA-384 for keys of 3072-8192 bits.
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PKCS1_3072_8192_SHA384: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PKCS1_SHA384,
    verification_alg: &signature::RSA_PKCS1_3072_8192_SHA384,
};

/// RSA PSS signatures using SHA-256 for keys of 2048-8192 bits and of
/// type rsaEncryption; see [RFC 4055 Section 1.2].
///
/// [RFC 4055 Section 1.2]: https://tools.ietf.org/html/rfc4055#section-1.2
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PSS_2048_8192_SHA256_LEGACY_KEY: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PSS_SHA256,
    verification_alg: &signature::RSA_PSS_2048_8192_SHA256,
};

/// RSA PSS signatures using SHA-384 for keys of 2048-8192 bits and of
/// type rsaEncryption; see [RFC 4055 Section 1.2].
///
/// [RFC 4055 Section 1.2]: https://tools.ietf.org/html/rfc4055#section-1.2
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PSS_2048_8192_SHA384_LEGACY_KEY: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PSS_SHA384,
    verification_alg: &signature::RSA_PSS_2048_8192_SHA384,
};

/// RSA PSS signatures using SHA-512 for keys of 2048-8192 bits and of
/// type rsaEncryption; see [RFC 4055 Section 1.2].
///
/// [RFC 4055 Section 1.2]: https://tools.ietf.org/html/rfc4055#section-1.2
///
/// Requires the `alloc` feature.
#[cfg(feature = "alloc")]
pub static RSA_PSS_2048_8192_SHA512_LEGACY_KEY: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: RSA_ENCRYPTION,
    signature_alg_id: RSA_PSS_SHA512,
    verification_alg: &signature::RSA_PSS_2048_8192_SHA512,
};

/// ED25519 signatures according to RFC 8410
pub static ED25519: SignatureAlgorithm = SignatureAlgorithm {
    public_key_alg_id: ED_25519,
    signature_alg_id: ED_25519,
    verification_alg: &signature::ED25519,
};

struct AlgorithmIdentifier {
    asn1_id_value: untrusted::Input<'static>,
}

impl AlgorithmIdentifier {
    fn matches_algorithm_id_value(&self, encoded: untrusted::Input) -> bool {
        equal(encoded, self.asn1_id_value)
    }
}

// See src/data/README.md.

const ECDSA_P256: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-ecdsa-p256.der")),
};

const ECDSA_P384: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-ecdsa-p384.der")),
};

const ECDSA_SHA256: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-ecdsa-sha256.der")),
};

const ECDSA_SHA384: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-ecdsa-sha384.der")),
};

#[cfg(feature = "alloc")]
const RSA_ENCRYPTION: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-encryption.der")),
};

#[cfg(feature = "alloc")]
const RSA_PKCS1_SHA256: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-pkcs1-sha256.der")),
};

#[cfg(feature = "alloc")]
const RSA_PKCS1_SHA384: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-pkcs1-sha384.der")),
};

#[cfg(feature = "alloc")]
const RSA_PKCS1_SHA512: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-pkcs1-sha512.der")),
};

#[cfg(feature = "alloc")]
const RSA_PSS_SHA256: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-pss-sha256.der")),
};

#[cfg(feature = "alloc")]
const RSA_PSS_SHA384: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-pss-sha384.der")),
};

#[cfg(feature = "alloc")]
const RSA_PSS_SHA512: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-rsa-pss-sha512.der")),
};

const ED_25519: AlgorithmIdentifier = AlgorithmIdentifier {
    asn1_id_value: untrusted::Input::from(include_bytes!("data/alg-ed25519.der")),
};

#[cfg(test)]
mod tests {
    use crate::{der, signed_data, Error};
    use alloc::{string::String, vec::Vec};

    macro_rules! test_file_bytes {
        ( $file_name:expr ) => {
            include_bytes!(concat!(
                "../third-party/chromium/data/verify_signed_data/",
                $file_name
            ))
        };
    }

    // TODO: The expected results need to be modified for SHA-1 deprecation.

    macro_rules! test_verify_signed_data {
        ($fn_name:ident, $file_name:expr, $expected_result:expr) => {
            #[test]
            fn $fn_name() {
                test_verify_signed_data(test_file_bytes!($file_name), $expected_result);
            }
        };
    }

    fn test_verify_signed_data(file_contents: &[u8], expected_result: Result<(), Error>) {
        let tsd = parse_test_signed_data(file_contents);
        let spki_value = untrusted::Input::from(&tsd.spki);
        let spki_value = spki_value
            .read_all(Error::BadDer, |input| {
                der::expect_tag_and_get_value(input, der::Tag::Sequence)
            })
            .unwrap();

        // we can't use `parse_signed_data` because it requires `data`
        // to be an ASN.1 SEQUENCE, and that isn't the case with
        // Chromium's test data. TODO: The test data set should be
        // expanded with SEQUENCE-wrapped data so that we can actually
        // test `parse_signed_data`.

        let algorithm = untrusted::Input::from(&tsd.algorithm);
        let algorithm = algorithm
            .read_all(Error::BadDer, |input| {
                der::expect_tag_and_get_value(input, der::Tag::Sequence)
            })
            .unwrap();

        let signature = untrusted::Input::from(&tsd.signature);
        let signature = signature
            .read_all(Error::BadDer, |input| {
                der::bit_string_with_no_unused_bits(input)
            })
            .unwrap();

        let signed_data = signed_data::SignedData {
            data: untrusted::Input::from(&tsd.data),
            algorithm,
            signature,
        };

        assert_eq!(
            expected_result,
            signed_data::verify_signed_data(
                SUPPORTED_ALGORITHMS_IN_TESTS,
                spki_value,
                &signed_data
            )
        );
    }

    // XXX: This is testing code that isn't even in this module.
    macro_rules! test_verify_signed_data_signature_outer {
        ($fn_name:ident, $file_name:expr, $expected_result:expr) => {
            #[test]
            fn $fn_name() {
                test_verify_signed_data_signature_outer(
                    test_file_bytes!($file_name),
                    $expected_result,
                );
            }
        };
    }

    fn test_verify_signed_data_signature_outer(file_contents: &[u8], expected_error: Error) {
        let tsd = parse_test_signed_data(file_contents);
        let signature = untrusted::Input::from(&tsd.signature);
        assert_eq!(
            expected_error,
            signature
                .read_all(Error::BadDer, |input| {
                    der::bit_string_with_no_unused_bits(input)
                })
                .unwrap_err()
        );
    }

    // XXX: This is testing code that is not even in this module.
    macro_rules! test_parse_spki_bad_outer {
        ($fn_name:ident, $file_name:expr, $error:expr) => {
            #[test]
            fn $fn_name() {
                test_parse_spki_bad_outer(test_file_bytes!($file_name), $error)
            }
        };
    }

    fn test_parse_spki_bad_outer(file_contents: &[u8], expected_error: Error) {
        let tsd = parse_test_signed_data(file_contents);
        let spki = untrusted::Input::from(&tsd.spki);
        assert_eq!(
            expected_error,
            spki.read_all(Error::BadDer, |input| {
                der::expect_tag_and_get_value(input, der::Tag::Sequence)
            })
            .unwrap_err()
        );
    }

    const UNSUPPORTED_SIGNATURE_ALGORITHM_FOR_RSA_KEY: Error = if cfg!(feature = "alloc") {
        Error::UnsupportedSignatureAlgorithmForPublicKey
    } else {
        Error::UnsupportedSignatureAlgorithm
    };

    const INVALID_SIGNATURE_FOR_RSA_KEY: Error = if cfg!(feature = "alloc") {
        Error::InvalidSignatureForPublicKey
    } else {
        Error::UnsupportedSignatureAlgorithm
    };

    const OK_IF_RSA_AVAILABLE: Result<(), Error> = if cfg!(feature = "alloc") {
        Ok(())
    } else {
        Err(Error::UnsupportedSignatureAlgorithm)
    };

    // XXX: Some of the BadDER tests should have better error codes, maybe?

    // XXX: We should have a variant of this test with a SHA-256 digest that gives
    // `Error::UnsupportedSignatureAlgorithmForPublicKey`.
    test_verify_signed_data!(
        test_ecdsa_prime256v1_sha512_spki_params_null,
        "ecdsa-prime256v1-sha512-spki-params-null.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data_signature_outer!(
        test_ecdsa_prime256v1_sha512_unused_bits_signature,
        "ecdsa-prime256v1-sha512-unused-bits-signature.pem",
        Error::BadDer
    );
    // XXX: We should have a variant of this test with a SHA-256 digest that gives
    // `Error::UnsupportedSignatureAlgorithmForPublicKey`.
    test_verify_signed_data!(
        test_ecdsa_prime256v1_sha512_using_ecdh_key,
        "ecdsa-prime256v1-sha512-using-ecdh-key.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    // XXX: We should have a variant of this test with a SHA-256 digest that gives
    // `Error::UnsupportedSignatureAlgorithmForPublicKey`.
    test_verify_signed_data!(
        test_ecdsa_prime256v1_sha512_using_ecmqv_key,
        "ecdsa-prime256v1-sha512-using-ecmqv-key.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_ecdsa_prime256v1_sha512_using_rsa_algorithm,
        "ecdsa-prime256v1-sha512-using-rsa-algorithm.pem",
        Err(UNSUPPORTED_SIGNATURE_ALGORITHM_FOR_RSA_KEY)
    );
    // XXX: We should have a variant of this test with a SHA-256 digest that gives
    // `Error::InvalidSignatureForPublicKey`.
    test_verify_signed_data!(
        test_ecdsa_prime256v1_sha512_wrong_signature_format,
        "ecdsa-prime256v1-sha512-wrong-signature-format.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    // Differs from Chromium because we don't support P-256 with SHA-512.
    test_verify_signed_data!(
        test_ecdsa_prime256v1_sha512,
        "ecdsa-prime256v1-sha512.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_ecdsa_secp384r1_sha256_corrupted_data,
        "ecdsa-secp384r1-sha256-corrupted-data.pem",
        Err(Error::InvalidSignatureForPublicKey)
    );
    test_verify_signed_data!(
        test_ecdsa_secp384r1_sha256,
        "ecdsa-secp384r1-sha256.pem",
        Ok(())
    );
    test_verify_signed_data!(
        test_ecdsa_using_rsa_key,
        "ecdsa-using-rsa-key.pem",
        Err(Error::UnsupportedSignatureAlgorithmForPublicKey)
    );

    test_parse_spki_bad_outer!(
        test_rsa_pkcs1_sha1_bad_key_der_length,
        "rsa-pkcs1-sha1-bad-key-der-length.pem",
        Error::BadDer
    );
    test_parse_spki_bad_outer!(
        test_rsa_pkcs1_sha1_bad_key_der_null,
        "rsa-pkcs1-sha1-bad-key-der-null.pem",
        Error::BadDer
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha1_key_params_absent,
        "rsa-pkcs1-sha1-key-params-absent.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha1_using_pss_key_no_params,
        "rsa-pkcs1-sha1-using-pss-key-no-params.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha1_wrong_algorithm,
        "rsa-pkcs1-sha1-wrong-algorithm.pem",
        Err(INVALID_SIGNATURE_FOR_RSA_KEY)
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha1,
        "rsa-pkcs1-sha1.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    // XXX: RSA PKCS#1 with SHA-1 is a supported algorithm, but we only accept
    // 2048-8192 bit keys, and this test file is using a 1024 bit key. Thus,
    // our results differ from Chromium's. TODO: this means we need a 2048+ bit
    // version of this test.
    test_verify_signed_data!(
        test_rsa_pkcs1_sha256,
        "rsa-pkcs1-sha256.pem",
        Err(INVALID_SIGNATURE_FOR_RSA_KEY)
    );
    test_parse_spki_bad_outer!(
        test_rsa_pkcs1_sha256_key_encoded_ber,
        "rsa-pkcs1-sha256-key-encoded-ber.pem",
        Error::BadDer
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha256_spki_non_null_params,
        "rsa-pkcs1-sha256-spki-non-null-params.pem",
        Err(UNSUPPORTED_SIGNATURE_ALGORITHM_FOR_RSA_KEY)
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha256_using_ecdsa_algorithm,
        "rsa-pkcs1-sha256-using-ecdsa-algorithm.pem",
        Err(Error::UnsupportedSignatureAlgorithmForPublicKey)
    );
    test_verify_signed_data!(
        test_rsa_pkcs1_sha256_using_id_ea_rsa,
        "rsa-pkcs1-sha256-using-id-ea-rsa.pem",
        Err(UNSUPPORTED_SIGNATURE_ALGORITHM_FOR_RSA_KEY)
    );

    // Chromium's PSS test are for parameter combinations we don't support.
    test_verify_signed_data!(
        test_rsa_pss_sha1_salt20_using_pss_key_no_params,
        "rsa-pss-sha1-salt20-using-pss-key-no-params.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha1_salt20_using_pss_key_with_null_params,
        "rsa-pss-sha1-salt20-using-pss-key-with-null-params.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha1_salt20,
        "rsa-pss-sha1-salt20.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha1_wrong_salt,
        "rsa-pss-sha1-wrong-salt.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha256_mgf1_sha512_salt33,
        "rsa-pss-sha256-mgf1-sha512-salt33.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha256_salt10_using_pss_key_with_params,
        "rsa-pss-sha256-salt10-using-pss-key-with-params.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha256_salt10_using_pss_key_with_wrong_params,
        "rsa-pss-sha256-salt10-using-pss-key-with-wrong-params.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha256_salt10,
        "rsa-pss-sha256-salt10.pem",
        Err(Error::UnsupportedSignatureAlgorithm)
    );

    // Our PSS tests that should work.
    test_verify_signed_data!(
        test_rsa_pss_sha256_salt32,
        "ours/rsa-pss-sha256-salt32.pem",
        OK_IF_RSA_AVAILABLE
    );
    test_verify_signed_data!(
        test_rsa_pss_sha384_salt48,
        "ours/rsa-pss-sha384-salt48.pem",
        OK_IF_RSA_AVAILABLE
    );
    test_verify_signed_data!(
        test_rsa_pss_sha512_salt64,
        "ours/rsa-pss-sha512-salt64.pem",
        OK_IF_RSA_AVAILABLE
    );
    test_verify_signed_data!(
        test_rsa_pss_sha256_salt32_corrupted_data,
        "ours/rsa-pss-sha256-salt32-corrupted-data.pem",
        Err(INVALID_SIGNATURE_FOR_RSA_KEY)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha384_salt48_corrupted_data,
        "ours/rsa-pss-sha384-salt48-corrupted-data.pem",
        Err(INVALID_SIGNATURE_FOR_RSA_KEY)
    );
    test_verify_signed_data!(
        test_rsa_pss_sha512_salt64_corrupted_data,
        "ours/rsa-pss-sha512-salt64-corrupted-data.pem",
        Err(INVALID_SIGNATURE_FOR_RSA_KEY)
    );

    test_verify_signed_data!(
        test_rsa_using_ec_key,
        "rsa-using-ec-key.pem",
        Err(UNSUPPORTED_SIGNATURE_ALGORITHM_FOR_RSA_KEY)
    );
    test_verify_signed_data!(
        test_rsa2048_pkcs1_sha512,
        "rsa2048-pkcs1-sha512.pem",
        OK_IF_RSA_AVAILABLE
    );

    struct TestSignedData {
        spki: Vec<u8>,
        data: Vec<u8>,
        algorithm: Vec<u8>,
        signature: Vec<u8>,
    }

    fn parse_test_signed_data(file_contents: &[u8]) -> TestSignedData {
        let mut lines = core::str::from_utf8(file_contents).unwrap().lines();
        let spki = read_pem_section(&mut lines, "PUBLIC KEY");
        let algorithm = read_pem_section(&mut lines, "ALGORITHM");
        let data = read_pem_section(&mut lines, "DATA");
        let signature = read_pem_section(&mut lines, "SIGNATURE");

        TestSignedData {
            spki,
            data,
            algorithm,
            signature,
        }
    }

    use alloc::str::Lines;

    fn read_pem_section(lines: &mut Lines, section_name: &str) -> Vec<u8> {
        // Skip comments and header
        let begin_section = format!("-----BEGIN {}-----", section_name);
        loop {
            let line = lines.next().unwrap();
            if line == begin_section {
                break;
            }
        }

        let mut base64 = String::new();

        let end_section = format!("-----END {}-----", section_name);
        loop {
            let line = lines.next().unwrap();
            if line == end_section {
                break;
            }
            base64.push_str(line);
        }

        base64::decode(&base64).unwrap()
    }

    static SUPPORTED_ALGORITHMS_IN_TESTS: &[&signed_data::SignatureAlgorithm] = &[
        // Reasonable algorithms.
        &signed_data::ECDSA_P256_SHA256,
        &signed_data::ECDSA_P384_SHA384,
        &signed_data::ED25519,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PKCS1_2048_8192_SHA256,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PKCS1_2048_8192_SHA384,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PKCS1_2048_8192_SHA512,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PKCS1_3072_8192_SHA384,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PSS_2048_8192_SHA256_LEGACY_KEY,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PSS_2048_8192_SHA384_LEGACY_KEY,
        #[cfg(feature = "alloc")]
        &signed_data::RSA_PSS_2048_8192_SHA512_LEGACY_KEY,
        // Algorithms deprecated because they are annoying (P-521) or because
        // they are nonsensical combinations.
        &signed_data::ECDSA_P256_SHA384, // Truncates digest.
        &signed_data::ECDSA_P384_SHA256, // Digest is unnecessarily short.
    ];
}