diff options
Diffstat (limited to 'lib/libssl/ssl_ciphers.c')
| -rw-r--r-- | lib/libssl/ssl_ciphers.c | 120 |
1 files changed, 119 insertions, 1 deletions
diff --git a/lib/libssl/ssl_ciphers.c b/lib/libssl/ssl_ciphers.c index 081a35ddb2b..374cb6684ed 100644 --- a/lib/libssl/ssl_ciphers.c +++ b/lib/libssl/ssl_ciphers.c @@ -1,5 +1,7 @@ -/* $OpenBSD: ssl_ciphers.c,v 1.1 2019/01/21 10:28:52 tb Exp $ */ +/* $OpenBSD: ssl_ciphers.c,v 1.2 2019/01/21 14:12:13 tb Exp $ */ /* + * Copyright (c) 2015-2017 Doug Hogan <doug@openbsd.org> + * Copyright (c) 2015-2018 Joel Sing <jsing@openbsd.org> * Copyright (c) 2019 Theo Buehler <tb@openbsd.org> * * Permission to use, copy, modify, and distribute this software for any @@ -15,6 +17,9 @@ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ +#include <openssl/safestack.h> + +#include "bytestring.h" #include "ssl_locl.h" int @@ -42,3 +47,116 @@ ssl_cipher_is_permitted(const SSL_CIPHER *cipher, uint16_t min_ver, return 0; } + +int +ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *ciphers, CBB *cbb) +{ + SSL_CIPHER *cipher; + int num_ciphers = 0; + uint16_t min_vers, max_vers; + int i; + + if (ciphers == NULL) + return 0; + + if (!ssl_supported_version_range(s, &min_vers, &max_vers)) + return 0; + + for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) { + if ((cipher = sk_SSL_CIPHER_value(ciphers, i)) == NULL) + return 0; + + if (!ssl_cipher_is_permitted(cipher, min_vers, max_vers)) + continue; + + if (!CBB_add_u16(cbb, ssl3_cipher_get_value(cipher))) + return 0; + + num_ciphers++; + } + + /* Add SCSV if there are other ciphers and we're not renegotiating. */ + if (num_ciphers > 0 && !s->internal->renegotiate) { + if (!CBB_add_u16(cbb, SSL3_CK_SCSV & SSL3_CK_VALUE_MASK)) + return 0; + } + + if (!CBB_flush(cbb)) + return 0; + + return 1; +} + +STACK_OF(SSL_CIPHER) * +ssl_bytes_to_cipher_list(SSL *s, CBS *cbs) +{ + STACK_OF(SSL_CIPHER) *ciphers = NULL; + const SSL_CIPHER *cipher; + uint16_t cipher_value, max_version; + unsigned long cipher_id; + + if (s->s3 != NULL) + S3I(s)->send_connection_binding = 0; + + if ((ciphers = sk_SSL_CIPHER_new_null()) == NULL) { + SSLerror(s, ERR_R_MALLOC_FAILURE); + goto err; + } + + while (CBS_len(cbs) > 0) { + if (!CBS_get_u16(cbs, &cipher_value)) { + SSLerror(s, SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST); + goto err; + } + + cipher_id = SSL3_CK_ID | cipher_value; + + if (s->s3 != NULL && cipher_id == SSL3_CK_SCSV) { + /* + * TLS_EMPTY_RENEGOTIATION_INFO_SCSV is fatal if + * renegotiating. + */ + if (s->internal->renegotiate) { + SSLerror(s, SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING); + ssl3_send_alert(s, SSL3_AL_FATAL, + SSL_AD_HANDSHAKE_FAILURE); + + goto err; + } + S3I(s)->send_connection_binding = 1; + continue; + } + + if (cipher_id == SSL3_CK_FALLBACK_SCSV) { + /* + * TLS_FALLBACK_SCSV indicates that the client + * previously tried a higher protocol version. + * Fail if the current version is an unexpected + * downgrade. + */ + max_version = ssl_max_server_version(s); + if (max_version == 0 || s->version < max_version) { + SSLerror(s, SSL_R_INAPPROPRIATE_FALLBACK); + if (s->s3 != NULL) + ssl3_send_alert(s, SSL3_AL_FATAL, + SSL_AD_INAPPROPRIATE_FALLBACK); + goto err; + } + continue; + } + + if ((cipher = ssl3_get_cipher_by_value(cipher_value)) != NULL) { + if (!sk_SSL_CIPHER_push(ciphers, cipher)) { + SSLerror(s, ERR_R_MALLOC_FAILURE); + goto err; + } + } + } + + return (ciphers); + + err: + sk_SSL_CIPHER_free(ciphers); + + return (NULL); +} |