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Abort handshake if signature algorithm used not supported by peer.

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This commit is contained in:
Dr. Stephen Henson 2012-07-24 18:11:27 +00:00
parent d18b716d25
commit ec4a50b3c3
7 changed files with 63 additions and 34 deletions
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6
CHANGES
View file

@ -4,6 +4,12 @@
Changes between 1.0.1 and 1.1.0 [xx XXX xxxx]
*) If an attempt is made to use a signature algorithm not in the peer
preference list abort the handshake. If client has no suitable
signature algorithms in response to a certificate request do not
use the certificate.
[Steve Henson]
*) If server EC tmp key is not in client preference list abort handshake.
[Steve Henson]

25
ssl/s3_clnt.c
View file

@ -1750,24 +1750,11 @@ int ssl3_get_key_exchange(SSL *s)
{
if (TLS1_get_version(s) >= TLS1_2_VERSION)
{
int sigalg = tls12_get_sigid(pkey);
/* Should never happen */
if (sigalg == -1)
{
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,ERR_R_INTERNAL_ERROR);
int rv = tls12_check_peer_sigalg(&md, s, p, pkey);
if (rv == -1)
goto err;
}
/* Check key type is consistent with signature */
if (sigalg != (int)p[1])
else if (rv == 0)
{
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_WRONG_SIGNATURE_TYPE);
al=SSL_AD_DECODE_ERROR;
goto f_err;
}
md = tls12_get_hash(p[0]);
if (md == NULL)
{
SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,SSL_R_UNKNOWN_DIGEST);
al = SSL_AD_DECODE_ERROR;
goto f_err;
}
@ -3161,13 +3148,17 @@ err:
}
/* Check a certificate can be used for client authentication. Currently
* just check cert exists and if static DH client certificates can be used.
* check cert exists, if we have a suitable digest for TLS 1.2 and if
* static DH client certificates can be used.
*/
static int ssl3_check_client_certificate(SSL *s)
{
unsigned long alg_k;
if (!s->cert || !s->cert->key->x509 || !s->cert->key->privatekey)
return 0;
/* If no suitable signature algorithm can't use certificate */
if (TLS1_get_version(s) >= TLS1_2_VERSION && !s->cert->key->digest)
return 0;
alg_k=s->s3->tmp.new_cipher->algorithm_mkey;
/* See if we can use client certificate for fixed DH */
if (alg_k & (SSL_kDHr|SSL_kDHd))

17
ssl/s3_srvr.c
View file

@ -3051,25 +3051,14 @@ int ssl3_get_cert_verify(SSL *s)
{
if (TLS1_get_version(s) >= TLS1_2_VERSION)
{
int sigalg = tls12_get_sigid(pkey);
/* Should never happen */
if (sigalg == -1)
int rv = tls12_check_peer_sigalg(&md, s, p, pkey);
if (rv == -1)
{
SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,ERR_R_INTERNAL_ERROR);
al = SSL_AD_INTERNAL_ERROR;
goto f_err;
}
/* Check key type is consistent with signature */
if (sigalg != (int)p[1])
else if (rv == 0)
{
SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,SSL_R_WRONG_SIGNATURE_TYPE);
al=SSL_AD_DECODE_ERROR;
goto f_err;
}
md = tls12_get_hash(p[0]);
if (md == NULL)
{
SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,SSL_R_UNKNOWN_DIGEST);
al = SSL_AD_DECODE_ERROR;
goto f_err;
}

1
ssl/ssl.h
View file

@ -2452,6 +2452,7 @@ void ERR_load_SSL_strings(void);
#define SSL_F_SSL_USE_RSAPRIVATEKEY_FILE 206
#define SSL_F_SSL_VERIFY_CERT_CHAIN 207
#define SSL_F_SSL_WRITE 208
#define SSL_F_TLS12_CHECK_PEER_SIGALG 333
#define SSL_F_TLS1_CERT_VERIFY_MAC 286
#define SSL_F_TLS1_CHANGE_CIPHER_STATE 209
#define SSL_F_TLS1_CHECK_SERVERHELLO_TLSEXT 274

1
ssl/ssl_err.c
View file

@ -288,6 +288,7 @@ static ERR_STRING_DATA SSL_str_functs[]=
{ERR_FUNC(SSL_F_SSL_USE_RSAPRIVATEKEY_FILE), "SSL_use_RSAPrivateKey_file"},
{ERR_FUNC(SSL_F_SSL_VERIFY_CERT_CHAIN), "ssl_verify_cert_chain"},
{ERR_FUNC(SSL_F_SSL_WRITE), "SSL_write"},
{ERR_FUNC(SSL_F_TLS12_CHECK_PEER_SIGALG), "tls12_check_peer_sigalg"},
{ERR_FUNC(SSL_F_TLS1_CERT_VERIFY_MAC), "tls1_cert_verify_mac"},
{ERR_FUNC(SSL_F_TLS1_CHANGE_CIPHER_STATE), "tls1_change_cipher_state"},
{ERR_FUNC(SSL_F_TLS1_CHECK_SERVERHELLO_TLSEXT), "TLS1_CHECK_SERVERHELLO_TLSEXT"},

2
ssl/ssl_locl.h
View file

@ -1252,6 +1252,8 @@ int ssl_parse_clienthello_renegotiate_ext(SSL *s, unsigned char *d, int len,
long ssl_get_algorithm2(SSL *s);
int tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize);
size_t tls12_get_psigalgs(SSL *s, const unsigned char **psigs);
int tls12_check_peer_sigalg(const EVP_MD **pmd, SSL *s,
const unsigned char *sig, EVP_PKEY *pkey);
void ssl_set_client_disabled(SSL *s);
int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen);

39
ssl/t1_lib.c
View file

@ -680,6 +680,45 @@ size_t tls12_get_psigalgs(SSL *s, const unsigned char **psigs)
return sizeof(tls12_sigalgs);
}
}
/* Check signature algorithm is consistent with sent supported signature
* algorithms and if so return relevant digest.
*/
int tls12_check_peer_sigalg(const EVP_MD **pmd, SSL *s,
const unsigned char *sig, EVP_PKEY *pkey)
{
const unsigned char *sent_sigs;
size_t sent_sigslen, i;
int sigalg = tls12_get_sigid(pkey);
/* Should never happen */
if (sigalg == -1)
return -1;
/* Check key type is consistent with signature */
if (sigalg != (int)sig[1])
{
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG,SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
/* Check signature matches a type we sent */
sent_sigslen = tls12_get_psigalgs(s, &sent_sigs);
for (i = 0; i < sent_sigslen; i+=2, sent_sigs+=2)
{
if (sig[0] == sent_sigs[0] && sig[1] == sent_sigs[1])
break;
}
/* Allow fallback to SHA1 if not strict mode */
if (i == sent_sigslen && (sig[0] != TLSEXT_hash_sha1 || s->cert->cert_flags & SSL_CERT_FLAG_TLS_STRICT))
{
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG,SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
*pmd = tls12_get_hash(sig[0]);
if (*pmd == NULL)
{
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG,SSL_R_UNKNOWN_DIGEST);
return 0;
}
return 1;
}
/* Get a mask of disabled algorithms: an algorithm is disabled
* if it isn't supported or doesn't appear in supported signature
* algorithms. Unlike ssl_cipher_get_disabled this applies to a specific