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14815a99 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | SSL_CTX_set1_sigalgs, SSL_set1_sigalgs, SSL_CTX_set1_sigalgs_list, | |
6 | SSL_set1_sigalgs_list, SSL_CTX_set1_client_sigalgs, | |
7 | SSL_set1_client_sigalgs, SSL_CTX_set1_client_sigalgs_list, | |
8 | SSL_set1_client_sigalgs_list - set supported signature algorithms | |
9 | ||
10 | =head1 SYNOPSIS | |
11 | ||
12 | #include <openssl/ssl.h> | |
13 | ||
14 | long SSL_CTX_set1_sigalgs(SSL_CTX *ctx, const int *slist, long slistlen); | |
15 | long SSL_set1_sigalgs(SSL *ssl, const int *slist, long slistlen); | |
16 | long SSL_CTX_set1_sigalgs_list(SSL_CTX *ctx, const char *str); | |
17 | long SSL_set1_sigalgs_list(SSL *ssl, const char *str); | |
18 | ||
19 | long SSL_CTX_set1_client_sigalgs(SSL_CTX *ctx, const int *slist, long slistlen); | |
20 | long SSL_set1_client_sigalgs(SSL *ssl, const int *slist, long slistlen); | |
21 | long SSL_CTX_set1_client_sigalgs_list(SSL_CTX *ctx, const char *str); | |
22 | long SSL_set1_client_sigalgs_list(SSL *ssl, const char *str); | |
23 | ||
24 | =head1 DESCRIPTION | |
25 | ||
26 | SSL_CTX_set1_sigalgs() and SSL_set1_sigalgs() set the supported signature | |
27 | algorithms for B<ctx> or B<ssl>. The array B<slist> of length B<slistlen> | |
28 | must consist of pairs of NIDs corresponding to digest and public key | |
29 | algorithms. | |
30 | ||
31 | SSL_CTX_set1_sigalgs_list() and SSL_set1_sigalgs_list() set the supported | |
32 | signature algorithms for B<ctx> or B<ssl>. The B<str> parameter | |
a6419d1e BK |
33 | must be a null terminated string consisting of a colon separated list of |
34 | elements, where each element is either a combination of a public key | |
35 | algorithm and a digest separated by B<+>, or a TLS 1.3-style named | |
cd2cdb61 TM |
36 | SignatureScheme such as rsa_pss_pss_sha256. If a list entry is preceded |
37 | with the C<?> character, it will be ignored if an implementation is missing. | |
38 | ||
14815a99 DSH |
39 | |
40 | SSL_CTX_set1_client_sigalgs(), SSL_set1_client_sigalgs(), | |
41 | SSL_CTX_set1_client_sigalgs_list() and SSL_set1_client_sigalgs_list() set | |
42 | signature algorithms related to client authentication, otherwise they are | |
43 | identical to SSL_CTX_set1_sigalgs(), SSL_set1_sigalgs(), | |
44 | SSL_CTX_set1_sigalgs_list() and SSL_set1_sigalgs_list(). | |
45 | ||
46 | All these functions are implemented as macros. The signature algorithm | |
47 | parameter (integer array or string) is not freed: the application should | |
48 | free it, if necessary. | |
49 | ||
50 | =head1 NOTES | |
51 | ||
52 | If an application wishes to allow the setting of signature algorithms | |
53 | as one of many user configurable options it should consider using the more | |
54 | flexible SSL_CONF API instead. | |
55 | ||
56 | The signature algorithms set by a client are used directly in the supported | |
57 | signature algorithm in the client hello message. | |
58 | ||
59 | The supported signature algorithms set by a server are not sent to the | |
60 | client but are used to determine the set of shared signature algorithms | |
61 | and (if server preferences are set with SSL_OP_CIPHER_SERVER_PREFERENCE) | |
62 | their order. | |
63 | ||
64 | The client authentication signature algorithms set by a server are sent | |
65 | in a certificate request message if client authentication is enabled, | |
66 | otherwise they are unused. | |
67 | ||
68 | Similarly client authentication signature algorithms set by a client are | |
69 | used to determined the set of client authentication shared signature | |
70 | algorithms. | |
71 | ||
72 | Signature algorithms will neither be advertised nor used if the security level | |
73 | prohibits them (for example SHA1 if the security level is 4 or more). | |
74 | ||
75 | Currently the NID_md5, NID_sha1, NID_sha224, NID_sha256, NID_sha384 and | |
76 | NID_sha512 digest NIDs are supported and the public key algorithm NIDs | |
a593cffe | 77 | EVP_PKEY_RSA, EVP_PKEY_RSA_PSS, EVP_PKEY_DSA and EVP_PKEY_EC. |
14815a99 DSH |
78 | |
79 | The short or long name values for digests can be used in a string (for | |
80 | example "MD5", "SHA1", "SHA224", "SHA256", "SHA384", "SHA512") and | |
a593cffe DSH |
81 | the public key algorithm strings "RSA", "RSA-PSS", "DSA" or "ECDSA". |
82 | ||
cf8e9233 | 83 | The TLS 1.3 signature scheme names (such as "rsa_pss_pss_sha256") can also |
a6419d1e | 84 | be used with the B<_list> forms of the API. |
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85 | |
86 | The use of MD5 as a digest is strongly discouraged due to security weaknesses. | |
87 | ||
4564e77a PY |
88 | =head1 RETURN VALUES |
89 | ||
90 | All these functions return 1 for success and 0 for failure. | |
91 | ||
14815a99 DSH |
92 | =head1 EXAMPLES |
93 | ||
0d4fb843 | 94 | Set supported signature algorithms to SHA256 with ECDSA and SHA256 with RSA |
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95 | using an array: |
96 | ||
2947af32 | 97 | const int slist[] = {NID_sha256, EVP_PKEY_EC, NID_sha256, EVP_PKEY_RSA}; |
14815a99 | 98 | |
2947af32 | 99 | SSL_CTX_set1_sigalgs(ctx, slist, 4); |
14815a99 | 100 | |
0d4fb843 | 101 | Set supported signature algorithms to SHA256 with ECDSA and SHA256 with RSA |
14815a99 DSH |
102 | using a string: |
103 | ||
2947af32 | 104 | SSL_CTX_set1_sigalgs_list(ctx, "ECDSA+SHA256:RSA+SHA256"); |
14815a99 | 105 | |
14815a99 DSH |
106 | =head1 SEE ALSO |
107 | ||
b97fdb57 | 108 | L<ssl(7)>, L<SSL_get_shared_sigalgs(3)>, |
9b86974e | 109 | L<SSL_CONF_CTX_new(3)> |
14815a99 | 110 | |
cd2cdb61 TM |
111 | =head1 HISTORY |
112 | ||
113 | Support for ignoring unknown signature algorithms in | |
114 | SSL_CTX_set1_sigalgs_list(), SSL_set1_sigalgs_list(), | |
115 | SSL_CTX_set1_client_sigalgs_list() and SSL_set1_client_sigalgs_list() | |
116 | was added in OpenSSL 3.3. | |
117 | ||
e2f92610 RS |
118 | =head1 COPYRIGHT |
119 | ||
b6461792 | 120 | Copyright 2015-2024 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 121 | |
4746f25a | 122 | Licensed under the Apache License 2.0 (the "License"). You may not use |
e2f92610 RS |
123 | this file except in compliance with the License. You can obtain a copy |
124 | in the file LICENSE in the source distribution or at | |
125 | L<https://www.openssl.org/source/license.html>. | |
126 | ||
127 | =cut |