ring 0.13.0-alpha3

Safe, fast, small crypto using Rust.
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

// Copyright 2015-2016 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 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.

/// RSA PKCS#1 1.5 signatures.

use core;
use {bits, digest, error, private, signature};
use super::{bigint, PUBLIC_KEY_PUBLIC_MODULUS_MAX_LEN, RSAParameters,
            parse_public_key};
use untrusted;


impl signature::VerificationAlgorithm for RSAParameters {
    fn verify(&self, public_key: untrusted::Input, msg: untrusted::Input,
              signature: untrusted::Input)
              -> Result<(), error::Unspecified> {
        let public_key = parse_public_key(public_key)?;
        verify_rsa(self, public_key, msg, signature)
    }
}

impl private::Private for RSAParameters {}

impl core::fmt::Debug for RSAParameters {
    fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
        use super::RSAParametersID::*;
        // XXX: This doesn't include the padding algorithm nor the size range.
        write!(f, "ring::signature::{}", match self.id {
            RSA_PKCS1_2048_8192_SHA1 => "RSA_PKCS1_2048_8192_SHA1",
            RSA_PKCS1_2048_8192_SHA256 => "RSA_PKCS1_2048_8192_SHA256",
            RSA_PKCS1_2048_8192_SHA384 => "RSA_PKCS1_2048_8192_SHA384",
            RSA_PKCS1_2048_8192_SHA512 => "RSA_PKCS1_2048_8192_SHA512",
            RSA_PKCS1_3072_8192_SHA384 => "RSA_PKCS1_3072_8192_SHA384",
            RSA_PSS_2048_8192_SHA256 => "RSA_PSS_2048_8192_SHA256",
            RSA_PSS_2048_8192_SHA384 => "RSA_PSS_2048_8192_SHA384",
            RSA_PSS_2048_8192_SHA512 => "RSA_PSS_2048_8192_SHA512",
        })
    }
}

macro_rules! rsa_params {
    ( $VERIFY_ALGORITHM:ident, $min_bits:expr, $PADDING_ALGORITHM:expr,
      $doc_str:expr ) => {
        #[doc=$doc_str]
        ///
        /// Only available in `use_heap` mode.
        pub static $VERIFY_ALGORITHM: RSAParameters =
            RSAParameters {
                padding_alg: $PADDING_ALGORITHM,
                min_bits: bits::BitLength($min_bits),
                id: super::RSAParametersID::$VERIFY_ALGORITHM,
            };
    }
}

rsa_params!(RSA_PKCS1_2048_8192_SHA1, 2048, &super::padding::RSA_PKCS1_SHA1,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PKCS#1.5 padding, and SHA-1.\n\nSee \"`RSA_PKCS1_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");
rsa_params!(RSA_PKCS1_2048_8192_SHA256, 2048, &super::RSA_PKCS1_SHA256,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PKCS#1.5 padding, and SHA-256.\n\nSee \"`RSA_PKCS1_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");
rsa_params!(RSA_PKCS1_2048_8192_SHA384, 2048, &super::RSA_PKCS1_SHA384,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PKCS#1.5 padding, and SHA-384.\n\nSee \"`RSA_PKCS1_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");
rsa_params!(RSA_PKCS1_2048_8192_SHA512, 2048, &super::RSA_PKCS1_SHA512,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PKCS#1.5 padding, and SHA-512.\n\nSee \"`RSA_PKCS1_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");
rsa_params!(RSA_PKCS1_3072_8192_SHA384, 3072, &super::RSA_PKCS1_SHA384,
            "Verification of signatures using RSA keys of 3072-8192 bits,
             PKCS#1.5 padding, and SHA-384.\n\nSee \"`RSA_PKCS1_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");

rsa_params!(RSA_PSS_2048_8192_SHA256, 2048, &super::RSA_PSS_SHA256,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PSS padding, and SHA-256.\n\nSee \"`RSA_PSS_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");
rsa_params!(RSA_PSS_2048_8192_SHA384, 2048, &super::RSA_PSS_SHA384,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PSS padding, and SHA-384.\n\nSee \"`RSA_PSS_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");
rsa_params!(RSA_PSS_2048_8192_SHA512, 2048, &super::RSA_PSS_SHA512,
            "Verification of signatures using RSA keys of 2048-8192 bits,
             PSS padding, and SHA-512.\n\nSee \"`RSA_PSS_*` Details\" in
             `ring::signature`'s module-level documentation for more details.");


/// Lower-level API for the verification of RSA signatures.
///
/// When the public key is in DER-encoded PKCS#1 ASN.1 format, it is
/// recommended to use `ring::signature::verify()` with
/// `ring::signature::RSA_PKCS1_*`, because `ring::signature::verify()`
/// will handle the parsing in that case. Otherwise, this function can be used
/// to pass in the raw bytes for the public key components as
/// `untrusted::Input` arguments.
///
/// `params` determine what algorithm parameters (padding, digest algorithm,
/// key length range, etc.) are used in the verification. `msg` is the message
/// and `signature` is the signature.
///
/// `n` is the public key modulus and `e` is the public key exponent. Both are
/// interpreted as unsigned big-endian encoded values. Both must be positive
/// and neither may have any leading zeros.
//
// There are a small number of tests that test `verify_rsa` directly, but the
// test coverage for this function mostly depends on the test coverage for the
// `signature::VerificationAlgorithm` implementation for `RSAParameters`. If we
// change that, test coverage for `verify_rsa()` will need to be reconsidered.
// (The NIST test vectors were originally in a form that was optimized for
// testing `verify_rsa` directly, but the testing work for RSA PKCS#1
// verification was done during the implementation of
// `signature::VerificationAlgorithm`, before `verify_rsa` was factored out).
pub fn verify_rsa(params: &RSAParameters,
                  (n, e): (untrusted::Input, untrusted::Input),
                  msg: untrusted::Input, signature: untrusted::Input)
                  -> Result<(), error::Unspecified> {
    let max_bits = bits::BitLength::from_usize_bytes(
        PUBLIC_KEY_PUBLIC_MODULUS_MAX_LEN)?;

    // Partially validate the public key. See
    // `check_public_modulus_and_exponent()` for more details.

    // XXX: FIPS 186-4 seems to indicate that the minimum
    // exponent value is 2**16 + 1, but it isn't clear if this is just for
    // signing or also for verification. We support exponents of 3 and larger
    // for compatibility with other commonly-used crypto libraries.
    let (n, n_bits, e) =
        super::check_public_modulus_and_exponent(n, e, params.min_bits, max_bits, 3)?;

    // The signature must be the same length as the modulus, in bytes.
    if signature.len() != n_bits.as_usize_bytes_rounded_up() {
        return Err(error::Unspecified);
    }

    // RFC 8017 Section 5.2.2: RSAVP1.

    // Step 1.
    let s = bigint::Elem::from_be_bytes_padded(signature, &n)?;
    if s.is_zero() {
        return Err(error::Unspecified);
    }

    // Step 2.
    // Montgomery encode `s`.
    let s = bigint::elem_mul(bigint::One::newRR(&n).as_ref(), s, &n);
    let m = bigint::elem_exp_vartime(s, e, &n);
    let m = m.into_unencoded(&n);

    // Step 3.
    let mut decoded = [0u8; PUBLIC_KEY_PUBLIC_MODULUS_MAX_LEN];
    let decoded = &mut decoded[..n_bits.as_usize_bytes_rounded_up()];
    m.fill_be_bytes(decoded);

    // Verify the padded message is correct.
    let m_hash = digest::digest(params.padding_alg.digest_alg(),
                                msg.as_slice_less_safe());
    untrusted::Input::from(decoded).read_all(
        error::Unspecified, |m| params.padding_alg.verify(&m_hash, m, n_bits))
}