Get overflow checks right in BN_bin2bn.
BN_bin2bn takes a size_t as it should, but it passes that into bn_wexpand which
takes unsigned. Switch bn_wexpand and bn_expand to take size_t before they
check bounds against INT_MAX.
BIGNUM itself still uses int everywhere and we may want to audit all the
arithmetic at some point. Although I suspect having bn_expand require that the
number of bits fit in an int is sufficient to make everything happy, unless
we're doing interesting arithmetic on the number of bits somewhere.
Change-Id: Id191a4a095adb7c938cde6f5a28bee56644720c6
Reviewed-on: https://boringssl-review.googlesource.com/5680
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/bn/internal.h b/crypto/bn/internal.h
index 2674b3c..0d0eb44 100644
--- a/crypto/bn/internal.h
+++ b/crypto/bn/internal.h
@@ -136,9 +136,9 @@
extern "C" {
#endif
-/* bn_expand acts the same as |BN_wexpand|, but takes a number of bits rather
+/* bn_expand acts the same as |bn_wexpand|, but takes a number of bits rather
* than a number of words. */
-BIGNUM *bn_expand(BIGNUM *bn, unsigned bits);
+BIGNUM *bn_expand(BIGNUM *bn, size_t bits);
#if defined(OPENSSL_64_BIT)
