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/include/openssl/bn.h b/include/openssl/bn.h
index f84aba5..70c0546 100644
--- a/include/openssl/bn.h
+++ b/include/openssl/bn.h
@@ -322,7 +322,7 @@
/* bn_wexpand ensures that |bn| has at least |words| works of space without
* altering its value. It returns one on success or zero on allocation
* failure. */
-OPENSSL_EXPORT BIGNUM *bn_wexpand(BIGNUM *bn, unsigned words);
+OPENSSL_EXPORT BIGNUM *bn_wexpand(BIGNUM *bn, size_t words);
/* BIGNUM pools.
