Ensure all EVP calls have their returns checked where appropriate

There are lots of calls to EVP functions from within libssl There were
various places where we should probably check the return value but don't.
This adds these checks.

Reviewed-by: Richard Levitte <levitte@openssl.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index d8d2244ae5..1c3b726674 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -3165,8 +3165,11 @@ EVP_MD_CTX *ssl_replace_hash(EVP_MD_CTX **hash, const EVP_MD *md)
 {
     ssl_clear_hash_ctx(hash);
     *hash = EVP_MD_CTX_create();
-    if (md)
-        EVP_DigestInit_ex(*hash, md, NULL);
+    if (*hash == NULL || (md && EVP_DigestInit_ex(*hash, md, NULL) <= 0)) {
+        EVP_MD_CTX_destroy(*hash);
+        *hash = NULL;
+        return NULL;
+    }
     return *hash;
 }