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Support TLS_FALLBACK_SCSV.

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Reviewed-by: Rich Salz <rsalz@openssl.org>
This commit is contained in:
Bodo Moeller
2014-10-15 04:05:57 +02:00
parent 13f8ddacbe
commit 59dcfa21e5
16 changed files with 142 additions and 26 deletions
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60
ssl/ssl_lib.c
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@@ -1360,6 +1360,8 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
if (sk == NULL) return(0);
q=p;
if (put_cb == NULL)
put_cb = s->method->put_cipher_by_char;
for (i=0; i<sk_SSL_CIPHER_num(sk); i++)
{
@@ -1375,24 +1377,36 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
s->psk_client_callback == NULL)
continue;
#endif /* OPENSSL_NO_PSK */
j = put_cb ? put_cb(c,p) : ssl_put_cipher_by_char(s,c,p);
j = put_cb(c,p);
p+=j;
}
/* If p == q, no ciphers and caller indicates an error. Otherwise
* add SCSV if not renegotiating.
*/
if (p != q && !s->new_session)
/* If p == q, no ciphers; caller indicates an error.
* Otherwise, add applicable SCSVs. */
if (p != q)
{
static SSL_CIPHER scsv =
if (!s->new_session)
{
0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
j = put_cb ? put_cb(&scsv,p) : ssl_put_cipher_by_char(s,&scsv,p);
p+=j;
static SSL_CIPHER scsv =
{
0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
j = put_cb(&scsv,p);
p+=j;
#ifdef OPENSSL_RI_DEBUG
fprintf(stderr, "SCSV sent by client\n");
fprintf(stderr, "TLS_EMPTY_RENEGOTIATION_INFO_SCSV sent by client\n");
#endif
}
}
if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV)
{
static SSL_CIPHER scsv =
{
0, NULL, SSL3_CK_FALLBACK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
j = put_cb(&scsv,p);
p+=j;
}
}
return(p-q);
}
@@ -1403,11 +1417,12 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
const SSL_CIPHER *c;
STACK_OF(SSL_CIPHER) *sk;
int i,n;
if (s->s3)
s->s3->send_connection_binding = 0;
n=ssl_put_cipher_by_char(s,NULL,NULL);
if ((num%n) != 0)
if (n == 0 || (num%n) != 0)
{
SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST);
return(NULL);
@@ -1422,7 +1437,7 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
for (i=0; i<num; i+=n)
{
/* Check for SCSV */
/* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */
if (s->s3 && (n != 3 || !p[0]) &&
(p[n-2] == ((SSL3_CK_SCSV >> 8) & 0xff)) &&
(p[n-1] == (SSL3_CK_SCSV & 0xff)))
@@ -1442,6 +1457,23 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
continue;
}
/* Check for TLS_FALLBACK_SCSV */
if ((n != 3 || !p[0]) &&
(p[n-2] == ((SSL3_CK_FALLBACK_SCSV >> 8) & 0xff)) &&
(p[n-1] == (SSL3_CK_FALLBACK_SCSV & 0xff)))
{
/* The SCSV indicates that the client previously tried a higher version.
* Fail if the current version is an unexpected downgrade. */
if (!SSL_ctrl(s, SSL_CTRL_CHECK_PROTO_VERSION, 0, NULL))
{
SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,SSL_R_INAPPROPRIATE_FALLBACK);
if (s->s3)
ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_INAPPROPRIATE_FALLBACK);
goto err;
}
continue;
}
c=ssl_get_cipher_by_char(s,p);
p+=n;
if (c != NULL)