Check for BN_copy failures.

BN_copy can fail on malloc failure. The case in crypto/rsa was causing the
malloc tests in all_tests.go to infinite loop.

Change-Id: Id5900512013fba9960444d78a8c056aa4314fb2d
Reviewed-on: https://boringssl-review.googlesource.com/5110
Reviewed-by: Adam Langley <agl@google.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/crypto/bn/exponentiation.c b/crypto/bn/exponentiation.c
index d3063c9f..e0ea16e2 100644
--- a/crypto/bn/exponentiation.c
+++ b/crypto/bn/exponentiation.c
@@ -173,8 +173,8 @@ int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) {
     }
   }
 
-  if (r != rr) {
-    BN_copy(r, rr);
+  if (r != rr && !BN_copy(r, rr)) {
+    goto err;
   }
   ret = 1;