commit 7964a1d6768650b8d34da23842f3f14851722afc
author Adam Langley <agl@google.com> Wed Feb 05 15:23:07 2020 -0800
committer Adam Langley <agl@google.com> Mon Feb 10 17:43:35 2020 +0000
tree 0c150e76b26e1eef1c0be85270b13022fb5878b2
parent 7e43e2e8eecc9114f829e6d75cc3c04d1af57504

Check for overflow in massive mallocs.

Hopefully it never happens, but a malloc of nearly the whole address
space should fail cleanly.

Change-Id: I82499e3236a1a485f5518b1c048899b1df3e8488
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/39864
Reviewed-by: David Benjamin <davidben@google.com>

crypto/mem.c

diff --git a/crypto/mem.c b/crypto/mem.c
index 7fc5f98..a864a66 100644
--- a/crypto/mem.c
+++ b/crypto/mem.c
@@ -105,6 +105,10 @@
 }
 
 void *OPENSSL_malloc(size_t size) {
+  if (size + OPENSSL_MALLOC_PREFIX < size) {
+    return NULL;
+  }
+
   void *ptr = malloc(size + OPENSSL_MALLOC_PREFIX);
   if (ptr == NULL) {
     return NULL;