1 files changed, 19 insertions, 6 deletions

diff --git a/src/lib/libssl/ssl_ciph.c b/src/lib/libssl/ssl_ciph.c
index 393f0fbd18..664ff5456b 100644
--- a/src/lib/libssl/ssl_ciph.c
+++ b/src/lib/libssl/ssl_ciph.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_ciph.c,v 1.112 2020/04/09 17:24:11 jsing Exp $ */
+/* $OpenBSD: ssl_ciph.c,v 1.113 2020/04/09 17:54:38 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -907,7 +907,7 @@ ssl_cipher_strength_sort(CIPHER_ORDER **head_p, CIPHER_ORDER **tail_p)
 
 static int
 ssl_cipher_process_rulestr(const char *rule_str, CIPHER_ORDER **head_p,
-    CIPHER_ORDER **tail_p, const SSL_CIPHER **ca_list)
+    CIPHER_ORDER **tail_p, const SSL_CIPHER **ca_list, int *tls13_seen)
 {
         unsigned long alg_mkey, alg_auth, alg_enc, alg_mac, alg_ssl;
         unsigned long algo_strength;
@@ -916,6 +916,8 @@ ssl_cipher_process_rulestr(const char *rule_str, CIPHER_ORDER **head_p,
         const char *l, *buf;
         char ch;
 
+        *tls13_seen = 0;
+
         retval = 1;
         l = rule_str;
         for (;;) {
@@ -1083,6 +1085,8 @@ ssl_cipher_process_rulestr(const char *rule_str, CIPHER_ORDER **head_p,
                                  * pattern!
                                  */
                                 cipher_id = ca_list[j]->id;
+                                if (ca_list[j]->algorithm_ssl == SSL_TLSV1_3)
+                                        *tls13_seen = 1;
                         } else {
                                 /*
                                  * not an explicit ciphersuite; only in this
@@ -1128,6 +1132,8 @@ ssl_cipher_process_rulestr(const char *rule_str, CIPHER_ORDER **head_p,
                         while ((*l != '\0') && !ITEM_SEP(*l))
                                 l++;
                 } else if (found) {
+                        if (alg_ssl == SSL_TLSV1_3)
+                                *tls13_seen = 1;
                         ssl_cipher_apply_rule(cipher_id, alg_mkey, alg_auth,
                             alg_enc, alg_mac, alg_ssl, algo_strength, rule,
                             -1, head_p, tail_p);
@@ -1164,6 +1170,7 @@ ssl_create_cipher_list(const SSL_METHOD *ssl_method,
         const char *rule_p;
         CIPHER_ORDER *co_list = NULL, *head = NULL, *tail = NULL, *curr;
         const SSL_CIPHER **ca_list = NULL;
+        int tls13_seen = 0;
 
         /*
          * Return with error if nothing to do.
@@ -1279,14 +1286,15 @@ ssl_create_cipher_list(const SSL_METHOD *ssl_method,
         rule_p = rule_str;
         if (strncmp(rule_str, "DEFAULT", 7) == 0) {
                 ok = ssl_cipher_process_rulestr(SSL_DEFAULT_CIPHER_LIST,
-                &head, &tail, ca_list);
+                    &head, &tail, ca_list, &tls13_seen);
                 rule_p += 7;
                 if (*rule_p == ':')
                         rule_p++;
         }
 
         if (ok && (strlen(rule_p) > 0))
-                ok = ssl_cipher_process_rulestr(rule_p, &head, &tail, ca_list);
+                ok = ssl_cipher_process_rulestr(rule_p, &head, &tail, ca_list,
+                    &tls13_seen);
 
         free((void *)ca_list);  /* Not needed anymore */
 
@@ -1308,11 +1316,16 @@ ssl_create_cipher_list(const SSL_METHOD *ssl_method,
         /*
          * The cipher selection for the list is done. The ciphers are added
          * to the resulting precedence to the STACK_OF(SSL_CIPHER).
+         *
+         * If the rule string did not contain any references to TLSv1.3,
+         * include inactive TLSv1.3 cipher suites. This avoids attempts to
+         * use TLSv1.3 with an older rule string that does not include
+         * TLSv1.3 cipher suites.
          */
         for (curr = head; curr != NULL; curr = curr->next) {
-                if (curr->active) {
+                if (curr->active ||
+                    (!tls13_seen && curr->cipher->algorithm_ssl == SSL_TLSV1_3))
                         sk_SSL_CIPHER_push(cipherstack, curr->cipher);
-                }
         }
         free(co_list);  /* Not needed any longer */