1 files changed, 31 insertions, 45 deletions

diff --git a/src/lib/libssl/ssl_tlsext.c b/src/lib/libssl/ssl_tlsext.c
index c301b804d2..d802a6e135 100644
--- a/src/lib/libssl/ssl_tlsext.c
+++ b/src/lib/libssl/ssl_tlsext.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_tlsext.c,v 1.124 2022/07/20 14:15:50 tb Exp $ */
+/* $OpenBSD: ssl_tlsext.c,v 1.125 2022/07/20 15:16:06 tb Exp $ */
 /*
  * Copyright (c) 2016, 2017, 2019 Joel Sing <jsing@openbsd.org>
  * Copyright (c) 2017 Doug Hogan <doug@openbsd.org>
@@ -245,7 +245,9 @@ tlsext_supportedgroups_server_parse(SSL *s, uint16_t msg_type, CBS *cbs,
     int *alert)
 {
         CBS grouplist;
+        uint16_t *groups;
         size_t groups_len;
+        int i;
 
         if (!CBS_get_u16_length_prefixed(cbs, &grouplist))
                 goto err;
@@ -257,62 +259,46 @@ tlsext_supportedgroups_server_parse(SSL *s, uint16_t msg_type, CBS *cbs,
                 goto err;
         groups_len /= 2;
 
-        if (!s->internal->hit) {
-                uint16_t *groups;
-                int i;
-
-                if (s->s3->hs.tls13.hrr) {
-                        if (s->session->tlsext_supportedgroups == NULL) {
-                                *alert = SSL_AD_HANDSHAKE_FAILURE;
-                                return 0;
-                        }
-                        /*
-                         * In the case of TLSv1.3 the client cannot change
-                         * the supported groups.
-                         */
-                        if (groups_len != s->session->tlsext_supportedgroups_length) {
-                                *alert = SSL_AD_ILLEGAL_PARAMETER;
-                                return 0;
-                        }
-                        for (i = 0; i < groups_len; i++) {
-                                uint16_t group;
-
-                                if (!CBS_get_u16(&grouplist, &group))
-                                        goto err;
-                                if (s->session->tlsext_supportedgroups[i] != group) {
-                                        *alert = SSL_AD_ILLEGAL_PARAMETER;
-                                        return 0;
-                                }
-                        }
+        if (s->internal->hit)
+                return 1;
 
-                        return 1;
+        if (s->s3->hs.tls13.hrr) {
+                if (s->session->tlsext_supportedgroups == NULL) {
+                        *alert = SSL_AD_HANDSHAKE_FAILURE;
+                        return 0;
                 }
 
-                if (s->session->tlsext_supportedgroups != NULL)
-                        goto err;
+                /*
+                 * The ClientHello extension hashing ensures that the client
+                 * did not change its list of supported groups.
+                 */
 
-                if ((groups = reallocarray(NULL, groups_len,
-                    sizeof(uint16_t))) == NULL) {
-                        *alert = SSL_AD_INTERNAL_ERROR;
-                        return 0;
-                }
+                return 1;
+        }
 
-                for (i = 0; i < groups_len; i++) {
-                        if (!CBS_get_u16(&grouplist, &groups[i])) {
-                                free(groups);
-                                goto err;
-                        }
-                }
+        if (s->session->tlsext_supportedgroups != NULL)
+                goto err;
 
-                if (CBS_len(&grouplist) != 0) {
+        if ((groups = reallocarray(NULL, groups_len, sizeof(uint16_t))) == NULL) {
+                *alert = SSL_AD_INTERNAL_ERROR;
+                return 0;
+        }
+
+        for (i = 0; i < groups_len; i++) {
+                if (!CBS_get_u16(&grouplist, &groups[i])) {
                         free(groups);
                         goto err;
                 }
+        }
 
-                s->session->tlsext_supportedgroups = groups;
-                s->session->tlsext_supportedgroups_length = groups_len;
+        if (CBS_len(&grouplist) != 0) {
+                free(groups);
+                goto err;
         }
 
+        s->session->tlsext_supportedgroups = groups;
+        s->session->tlsext_supportedgroups_length = groups_len;
+
         return 1;
 
  err: