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Allow initial connection (but no renegoriation) to servers which don't support

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RI.
This commit is contained in:
Dr. Stephen Henson
2009-12-14 01:09:01 +00:00
parent c0e94f8292
commit 725745d105
1 changed files with 46 additions and 28 deletions
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74
ssl/t1_lib.c
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@@ -350,21 +350,27 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
unsigned short len; unsigned short len;
unsigned char *data = *p; unsigned char *data = *p;
int renegotiate_seen = 0; int renegotiate_seen = 0;
int need_ri;
s->servername_done = 0; s->servername_done = 0;
s->tlsext_status_type = -1; s->tlsext_status_type = -1;
/* Need RI if renegotiating unless legacy renegotiation allowed */
if (s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
|| !s->new_session)
need_ri = 0;
else
need_ri = 1;
if (data >= (d+n-2)) if (data >= (d+n-2))
{ {
if (s->new_session if (!need_ri)
&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) return 1;
{ /* We need to see at least one extension: RI */
/* We should always see one extension: the renegotiate extension */ /* FIXME: Spec currently doesn't give alert to use */
SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); *al = SSL_AD_ILLEGAL_PARAMETER;
*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */ SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT,
return 0; SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
} return 0;
return 1;
} }
n2s(data,len); n2s(data,len);
@@ -590,11 +596,12 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
data+=size; data+=size;
} }
if (s->new_session && !renegotiate_seen if (need_ri && !renegotiate_seen)
&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
{ {
*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */ /* FIXME: Spec currently doesn't give alert to use */
SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); *al = SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_TLSEXT,
SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
return 0; return 0;
} }
@@ -610,20 +617,30 @@ int ssl_parse_serverhello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
unsigned char *data = *p; unsigned char *data = *p;
int tlsext_servername = 0; int tlsext_servername = 0;
int renegotiate_seen = 0; int renegotiate_seen = 0;
int need_ri;
/* Determine if we need to see RI. Strictly speaking if we want to
* avoid an attack we should *always* see RI even on initial server
* hello because the client doesn't see any renegotiation during an
* attack. However this would mean we could not connect to any server
* which doesn't support RI so for the immediate future tolerate RI
* absence on initial connect only.
*/
if (s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION ||
!s->new_session)
need_ri = 0;
else
need_ri = 1;
if (data >= (d+n-2)) if (data >= (d+n-2))
{ {
/* Because the client does not see any renegotiation during an if (!need_ri)
attack, we must enforce this on all server hellos, even the return 1;
first */ /* We need to see at least one extension: RI */
if (!(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) /* FIXME: Spec currently doesn't give alert to use */
{ *al = SSL_AD_ILLEGAL_PARAMETER;
/* We should always see one extension: the renegotiate extension */ SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT,
*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */ SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); return 0;
return 0;
}
return 1;
} }
n2s(data,len); n2s(data,len);
@@ -688,11 +705,12 @@ int ssl_parse_serverhello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
return 0; return 0;
} }
if (!renegotiate_seen if (!renegotiate_seen && need_ri)
&& !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION))
{ {
*al = SSL_AD_ILLEGAL_PARAMETER; /* is this the right alert? */ /* FIXME: Spec currently doesn't give alert to use */
SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); *al = SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT,
SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
return 0; return 0;
} }