Fix supported_groups handing in TLSv1.2

In TLSv1.2 we should not attempt to use a supported_group value that is
intended for use with TLSv1.3 - even if both the server and the client
support it, e.g. the ffdhe groups are supported by OpenSSL for TLSv1.3 but
not for TLSv1.2.

Fixes #21081

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21295)
This commit is contained in:
Matt Caswell 2023-06-23 15:45:14 +01:00
parent f41c7125f7
commit 01e765f054

View File

@ -23,6 +23,7 @@
#include "internal/nelem.h"
#include "internal/sizes.h"
#include "internal/tlsgroups.h"
#include "internal/cryptlib.h"
#include "ssl_local.h"
#include <openssl/ct.h>
@ -600,6 +601,7 @@ uint16_t tls1_shared_group(SSL *s, int nmatch)
const uint16_t *pref, *supp;
size_t num_pref, num_supp, i;
int k;
SSL_CTX *ctx = s->ctx;
/* Can't do anything on client side */
if (s->server == 0)
@ -636,10 +638,29 @@ uint16_t tls1_shared_group(SSL *s, int nmatch)
for (k = 0, i = 0; i < num_pref; i++) {
uint16_t id = pref[i];
const TLS_GROUP_INFO *inf;
if (!tls1_in_list(id, supp, num_supp)
|| !tls_group_allowed(s, id, SSL_SECOP_CURVE_SHARED))
continue;
|| !tls_group_allowed(s, id, SSL_SECOP_CURVE_SHARED))
continue;
inf = tls1_group_id_lookup(ctx, id);
if (!ossl_assert(inf != NULL))
return 0;
if (SSL_IS_DTLS(s)) {
if (inf->maxdtls == -1)
continue;
if ((inf->mindtls != 0 && DTLS_VERSION_LT(s->version, inf->mindtls))
|| (inf->maxdtls != 0
&& DTLS_VERSION_GT(s->version, inf->maxdtls)))
continue;
} else {
if (inf->maxtls == -1)
continue;
if ((inf->mintls != 0 && s->version < inf->mintls)
|| (inf->maxtls != 0 && s->version > inf->maxtls))
continue;
}
if (nmatch == k)
return id;
k++;