From f9fc1ec28baeeef6259127b3cbeb34986834574f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 11 Aug 2023 15:46:33 +0200 Subject: crypto: drivers - avoid memcpy size warning Some configurations with gcc-12 or gcc-13 produce a warning for the source and destination of a memcpy() in atmel_sha_hmac_compute_ipad_hash() potentially overlapping: In file included from include/linux/string.h:254, from drivers/crypto/atmel-sha.c:15: drivers/crypto/atmel-sha.c: In function 'atmel_sha_hmac_compute_ipad_hash': include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing 129 or more bytes at offsets 408 and 280 overlaps 1 or more bytes at offset 408 [-Werror=restrict] 57 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:648:9: note: in expansion of macro '__underlying_memcpy' 648 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:693:26: note: in expansion of macro '__fortify_memcpy_chk' 693 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ drivers/crypto/atmel-sha.c:1773:9: note: in expansion of macro 'memcpy' 1773 | memcpy(hmac->opad, hmac->ipad, bs); | ^~~~~~ The same thing happens in two more drivers that have the same logic: drivers/crypto/chelsio/chcr_algo.c: In function 'chcr_ahash_setkey': include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing 129 or more bytes at offsets 260 and 132 overlaps 1 or more bytes at offset 260 [-Werror=restrict] drivers/crypto/bcm/cipher.c: In function 'ahash_hmac_setkey': include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing between 129 and 4294967295 bytes at offsets 840 and 712 overlaps between 1 and 4294967167 bytes at offset 840 [-Werror=restrict] I don't think it can actually happen because the size is strictly bounded to the available block sizes, at most 128 bytes, though inlining decisions could lead gcc to not see that. Use the unsafe_memcpy() helper instead of memcpy(), with the only difference being that this skips the hardening checks that produce the warning. Suggested-by: Herbert Xu Signed-off-by: Arnd Bergmann Signed-off-by: Herbert Xu --- drivers/crypto/chelsio/chcr_algo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/crypto/chelsio/chcr_algo.c') diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c index 0eade4fa6695..16298ae4a00b 100644 --- a/drivers/crypto/chelsio/chcr_algo.c +++ b/drivers/crypto/chelsio/chcr_algo.c @@ -2216,7 +2216,8 @@ static int chcr_ahash_setkey(struct crypto_ahash *tfm, const u8 *key, memcpy(hmacctx->ipad, key, keylen); } memset(hmacctx->ipad + keylen, 0, bs - keylen); - memcpy(hmacctx->opad, hmacctx->ipad, bs); + unsafe_memcpy(hmacctx->opad, hmacctx->ipad, bs, + "fortified memcpy causes -Wrestrict warning"); for (i = 0; i < bs / sizeof(int); i++) { *((unsigned int *)(&hmacctx->ipad) + i) ^= IPAD_DATA; -- cgit