Fix a ssl session leak due to OOM in lh_SSL_SESSION_insert

- s == NULL can mean c is a new session *or* lh_insert was
  unable to create a hash entry.
- use lh_SSL_SESSION_retrieve to check for this error condition.
- If it happens simply remove the extra reference again.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2138)
(cherry picked from commit 38088ce9934a90d4aea486edbff864f3935342e6)

diff --git a/ssl/ssl_sess.c b/ssl/ssl_sess.c
index ed9855f90cf8124ad96d2d06667ae7e73147401b..c3369a44aea7e215ba6c3f230d12f9febb296c6f 100644 (file)
--- a/ssl/ssl_sess.c
+++ b/ssl/ssl_sess.c
@@ -769,6 +769,15 @@ int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
          * obtain the same session from an external cache)
          */
         s = NULL;
+    } else if (s == NULL &&
+               lh_SSL_SESSION_retrieve(ctx->sessions, c) == NULL) {
+        /* s == NULL can also mean OOM error in lh_SSL_SESSION_insert ... */
+
+        /*
+         * ... so take back the extra reference and also don't add
+         * the session to the SSL_SESSION_list at this time
+         */
+        s = c;
     }
 
     /* Put at the head of the queue unless it is already in the cache */