Fix a race condition in ciphers handling

Similarly to the previous commit we were storing the peer offered list
of ciphers in the session. In practice there is no need for this
information to be avilable from one resumption to the next since this
list is specific to a particular handshake. Since the session object is
supposed to be immutable we should not be updating it once we have decided
to resume. The solution is to remove the session list out of the session
object.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/9162)

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 43a1099ba86248753a12294871751dd5a01daa89..220168a1485cd73511fd8e939841b7d4341ba2e5 100644 (file)
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1169,6 +1169,7 @@ void SSL_free(SSL *s)
     sk_SSL_CIPHER_free(s->cipher_list);
     sk_SSL_CIPHER_free(s->cipher_list_by_id);
     sk_SSL_CIPHER_free(s->tls13_ciphersuites);
+    sk_SSL_CIPHER_free(s->peer_ciphers);
 
     /* Make the next call work :-) */
     if (s->session != NULL) {
@@ -2571,9 +2572,9 @@ STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *s)
 
 STACK_OF(SSL_CIPHER) *SSL_get_client_ciphers(const SSL *s)
 {
-    if ((s == NULL) || (s->session == NULL) || !s->server)
+    if ((s == NULL) || !s->server)
         return NULL;
-    return s->session->ciphers;
+    return s->peer_ciphers;
 }
 
 STACK_OF(SSL_CIPHER) *SSL_get1_supported_ciphers(SSL *s)
@@ -2712,13 +2713,12 @@ char *SSL_get_shared_ciphers(const SSL *s, char *buf, int size)
     int i;
 
     if (!s->server
-            || s->session == NULL
-            || s->session->ciphers == NULL
+            || s->peer_ciphers == NULL
             || size < 2)
         return NULL;
 
     p = buf;
-    clntsk = s->session->ciphers;
+    clntsk = s->peer_ciphers;
     srvrsk = SSL_get_ciphers(s);
     if (clntsk == NULL || srvrsk == NULL)
         return NULL;

diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 2f76b66352d93de5adb06f55c853e736d9858d5e..9663c7c3bbed1024fdabe2856dfda2930ee5f5f4 100644 (file)
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -556,7 +556,6 @@ struct ssl_session_st {
     const SSL_CIPHER *cipher;
     unsigned long cipher_id;    /* when ASN.1 loaded, this needs to be used to
                                  * load the 'cipher' structure */
-    STACK_OF(SSL_CIPHER) *ciphers; /* ciphers offered by the client */
     CRYPTO_EX_DATA ex_data;     /* application specific data */
     /*
      * These are used to make removal of session-ids more efficient and to
@@ -1318,6 +1317,7 @@ struct ssl_st {
     /* Per connection DANE state */
     SSL_DANE dane;
     /* crypto */
+    STACK_OF(SSL_CIPHER) *peer_ciphers;
     STACK_OF(SSL_CIPHER) *cipher_list;
     STACK_OF(SSL_CIPHER) *cipher_list_by_id;
     /* TLSv1.3 specific ciphersuites */

diff --git a/ssl/ssl_sess.c b/ssl/ssl_sess.c
index 9809fcc882290941b722e0e3b19ba8b430857aa3..f13c909da79261eee837dbfc11aef296368e068b 100644 (file)
--- a/ssl/ssl_sess.c
+++ b/ssl/ssl_sess.c
@@ -121,7 +121,6 @@ SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
     dest->psk_identity_hint = NULL;
     dest->psk_identity = NULL;
 #endif
-    dest->ciphers = NULL;
     dest->ext.hostname = NULL;
 #ifndef OPENSSL_NO_EC
     dest->ext.ecpointformats = NULL;
@@ -175,12 +174,6 @@ SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
     }
 #endif
 
-    if (src->ciphers != NULL) {
-        dest->ciphers = sk_SSL_CIPHER_dup(src->ciphers);
-        if (dest->ciphers == NULL)
-            goto err;
-    }
-
     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_SSL_SESSION,
                             &dest->ex_data, &src->ex_data)) {
         goto err;
@@ -781,7 +774,6 @@ void SSL_SESSION_free(SSL_SESSION *ss)
     OPENSSL_cleanse(ss->session_id, sizeof(ss->session_id));
     X509_free(ss->peer);
     sk_X509_pop_free(ss->peer_chain, X509_free);
-    sk_SSL_CIPHER_free(ss->ciphers);
     OPENSSL_free(ss->ext.hostname);
     OPENSSL_free(ss->ext.tick);
 #ifndef OPENSSL_NO_EC

diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index 6504f4f74efe1e0423850f0c871200877acf0f95..79c2aa0ede2a11d1d512bd8938ec3347c0bb89fb 100644 (file)
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -1924,14 +1924,14 @@ static int tls_early_post_process_client_hello(SSL *s)
                 && master_key_length > 0) {
             s->session->master_key_length = master_key_length;
             s->hit = 1;
-            s->session->ciphers = ciphers;
+            s->peer_ciphers = ciphers;
             s->session->verify_result = X509_V_OK;
 
             ciphers = NULL;
 
             /* check if some cipher was preferred by call back */
             if (pref_cipher == NULL)
-                pref_cipher = ssl3_choose_cipher(s, s->session->ciphers,
+                pref_cipher = ssl3_choose_cipher(s, s->peer_ciphers,
                                                  SSL_get_ciphers(s));
             if (pref_cipher == NULL) {
                 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,
@@ -1942,9 +1942,9 @@ static int tls_early_post_process_client_hello(SSL *s)
 
             s->session->cipher = pref_cipher;
             sk_SSL_CIPHER_free(s->cipher_list);
-            s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
+            s->cipher_list = sk_SSL_CIPHER_dup(s->peer_ciphers);
             sk_SSL_CIPHER_free(s->cipher_list_by_id);
-            s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->session->ciphers);
+            s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->peer_ciphers);
         }
     }
 
@@ -2044,12 +2044,12 @@ static int tls_early_post_process_client_hello(SSL *s)
 #endif
 
     /*
-     * Given s->session->ciphers and SSL_get_ciphers, we must pick a cipher
+     * Given s->peer_ciphers and SSL_get_ciphers, we must pick a cipher
      */
 
     if (!s->hit || SSL_IS_TLS13(s)) {
-        sk_SSL_CIPHER_free(s->session->ciphers);
-        s->session->ciphers = ciphers;
+        sk_SSL_CIPHER_free(s->peer_ciphers);
+        s->peer_ciphers = ciphers;
         if (ciphers == NULL) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR,
                      SSL_F_TLS_EARLY_POST_PROCESS_CLIENT_HELLO,
@@ -2256,7 +2256,7 @@ WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
             /* In TLSv1.3 we selected the ciphersuite before resumption */
             if (!SSL_IS_TLS13(s)) {
                 cipher =
-                    ssl3_choose_cipher(s, s->session->ciphers, SSL_get_ciphers(s));
+                    ssl3_choose_cipher(s, s->peer_ciphers, SSL_get_ciphers(s));
 
                 if (cipher == NULL) {
                     SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE,