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>

4 files changed, 10 insertions, 11 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;
 
diff --git a/crypto/bn/mul.c b/crypto/bn/mul.c
index a17d766b..029a59e2 100644
--- a/crypto/bn/mul.c
+++ b/crypto/bn/mul.c
@@ -666,8 +666,8 @@ int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) {
 
 end:
   bn_correct_top(rr);
-  if (r != rr) {
-    BN_copy(r, rr);
+  if (r != rr && !BN_copy(r, rr)) {
+    goto err;
   }
   ret = 1;
 
@@ -877,8 +877,8 @@ int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) {
     rr->top = max;
   }
 
-  if (rr != r) {
-    BN_copy(r, rr);
+  if (rr != r && !BN_copy(r, rr)) {
+    goto err;
   }
   ret = 1;
 
diff --git a/crypto/bn/prime.c b/crypto/bn/prime.c
index cf3afcfd..655b4a56 100644
--- a/crypto/bn/prime.c
+++ b/crypto/bn/prime.c
@@ -515,11 +515,10 @@ int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
 
   /* A := abs(a) */
   if (a->neg) {
-    BIGNUM *t;
-    if ((t = BN_CTX_get(ctx)) == NULL) {
+    BIGNUM *t = BN_CTX_get(ctx);
+    if (t == NULL || !BN_copy(t, a)) {
       goto err;
     }
-    BN_copy(t, a);
     t->neg = 0;
     A = t;
   } else {
diff --git a/crypto/bn/sqrt.c b/crypto/bn/sqrt.c
index e71a8181..75f810e5 100644
--- a/crypto/bn/sqrt.c
+++ b/crypto/bn/sqrt.c
@@ -497,8 +497,8 @@ int BN_sqrt(BIGNUM *out_sqrt, const BIGNUM *in, BN_CTX *ctx) {
   ok = 1;
 
 err:
-  if (ok && out_sqrt == in) {
-    BN_copy(out_sqrt, estimate);
+  if (ok && out_sqrt == in && !BN_copy(out_sqrt, estimate)) {
+    ok = 0;
   }
   BN_CTX_end(ctx);
   return ok;