commit 1fcb4e4d521971caccb61df215541bf55f7ca9a5
author Benjamin Kaduk <bkaduk@akamai.com> Tue Oct 17 14:46:58 2017 -0500
committer Ben Kaduk <kaduk@mit.edu> Mon Oct 30 10:18:09 2017 -0500
tree 5b753dc364d8444f6b8d59abfa9c27dbd01b85bd
parent ce01b1896b57f3568c5af71e5b2912280171ba6e

Use atomics for SSL_CTX statistics

It is expected that SSL_CTX objects are shared across threads,
and as such we are responsible for ensuring coherent data accesses.
Aligned integer accesses ought to be atomic already on all supported
architectures, but we can be formally correct.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4549)

ssl/statem/statem_clnt.c

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index af42bcb..6b1bc92 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -1266,7 +1266,7 @@
     unsigned int compression;
     unsigned int sversion;
     unsigned int context;
-    int protverr;
+    int protverr, discard;
     RAW_EXTENSION *extensions = NULL;
 #ifndef OPENSSL_NO_COMP
     SSL_COMP *comp;
@@ -1430,7 +1430,8 @@
                 || (SSL_IS_TLS13(s)
                     && s->session->ext.tick_identity
                        != TLSEXT_PSK_BAD_IDENTITY)) {
-            s->ctx->stats.sess_miss++;
+            CRYPTO_atomic_add(&s->ctx->stats.sess_miss, 1, &discard,
+                              s->ctx->lock);
             if (!ssl_get_new_session(s, 0)) {
                 goto f_err;
             }