From b3fc17453bf586a99879a7bba03122a4f0b7aa6d Mon Sep 17 00:00:00 2001 From: Peter Wu Date: Tue, 7 Jul 2015 19:28:38 +0200 Subject: Fix undefined behavior wrt memcpy * cipher/cipher-gcm.c: Do not copy zero bytes from an empty buffer. Let the function continue to add padding as needed though. * cipher/mac-poly1305.c: If the caller requested to finish the hash function without a copy of the result, return immediately. -- Caught by UndefinedBehaviorSanitizer. Signed-off-by: Peter Wu --- cipher/cipher-gcm.c | 2 +- cipher/mac-poly1305.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/cipher/cipher-gcm.c b/cipher/cipher-gcm.c index 6b13fc55..3711a1df 100644 --- a/cipher/cipher-gcm.c +++ b/cipher/cipher-gcm.c @@ -474,7 +474,7 @@ do_ghash_buf(gcry_cipher_hd_t c, byte *hash, const byte *buf, do { - if (buflen + unused < blocksize || unused > 0) + if (buflen > 0 && (buflen + unused < blocksize || unused > 0)) { n = blocksize - unused; n = n < buflen ? n : buflen; diff --git a/cipher/mac-poly1305.c b/cipher/mac-poly1305.c index 76b369ac..b80f87db 100644 --- a/cipher/mac-poly1305.c +++ b/cipher/mac-poly1305.c @@ -260,6 +260,9 @@ poly1305mac_read (gcry_mac_hd_t h, unsigned char *outbuf, size_t *outlen) mac_ctx->marks.tag = 1; } + if (*outlen == 0) + return 0; + if (*outlen <= POLY1305_TAGLEN) buf_cpy (outbuf, mac_ctx->tag, *outlen); else -- cgit v1.2.1