Work around language and compiler bug in memcpy, etc.
Most C standard library functions are undefined if passed NULL, even
when the corresponding length is zero. This gives them (and, in turn,
all functions which call them) surprising behavior on empty arrays.
Some compilers will miscompile code due to this rule. See also
https://www.imperialviolet.org/2016/06/26/nonnull.html
Add OPENSSL_memcpy, etc., wrappers which avoid this problem.
BUG=23
Change-Id: I95f42b23e92945af0e681264fffaf578e7f8465e
Reviewed-on: https://boringssl-review.googlesource.com/12928
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/modes/cbc.c b/crypto/modes/cbc.c
index 6e9fe24..12d551c 100644
--- a/crypto/modes/cbc.c
+++ b/crypto/modes/cbc.c
@@ -103,7 +103,7 @@
out += 16;
}
- memcpy(ivec, iv, 16);
+ OPENSSL_memcpy(ivec, iv, 16);
}
void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
@@ -154,7 +154,7 @@
out += 16;
}
}
- memcpy(ivec, iv, 16);
+ OPENSSL_memcpy(ivec, iv, 16);
} else {
/* |out| is less than two blocks behind |in|. Decrypting an input block
* directly to |out| would overwrite a ciphertext block before it is used as
