crypto: xts - Replace memcpy() invocation with simple assignment
PATCH 1/1 crypto: xts - Replace memcpy() invocation with simple assignment
Colin reports that the memcpy() call in xts_cts_final() trigggers a "Overlapping buffer in memory copy" warning in Coverity, which is a false postive, given that tail is guaranteed to be smaller than or equal to the distance between source and destination.
However, given that any additional bytes that we copy will be ignored anyway, we can simply copy XTS_BLOCK_SIZE unconditionally, which means we can use struct assignment of the array members instead, which is likely to be more efficient as well.
Addresses-Coverity: ("Overlapping buffer in memory copy")
--- crypto/xts.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
crypto/xts.c +1 -1
@@ -171,7 +171,7 @@ static int xts_cts_final(struct skcipher_request *req, offset - XTS_BLOCK_SIZE);scatterwalk_map_and_copy (b, rctx->tail,0 ,XTS_BLOCK_SIZE ,0 ); -memcpy (b +1 , b, tail); + b[1 ] = b[0 ];scatterwalk_map_and_copy (b, req->src, offset, tail,0 );le128_xor (b, &rctx->t, b);
Signature · 1 line
2.17.1
Herbert Xu
maintainerQuoted 10 lines · Ard Biesheuvel
Colin reports that the
memcpy()call inxts_cts_final()trigggers a "Overlapping buffer in memory copy" warning in Coverity, which is a false postive, given that tail is guaranteed to be smaller than or equal to the distance between source and destination.However, given that any additional bytes that we copy will be ignored anyway, we can simply copy
XTS_BLOCK_SIZEunconditionally, which means we can use struct assignment of the array members instead, which is likely to be more efficient as well.
Quoted 7 lines
Addresses-Coverity: ("Overlapping buffer in memory copy")
Fixes 8083b1bf8163 ("crypto: xts - add support for ciphertext stealing")Reported-by Colin Ian King <[email protected]>Signed-off-by Ard Biesheuvel <[email protected]>--- crypto/xts.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Patch applied. Thanks.
Signature · 3 lines
Email: Herbert Xu <[email protected]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt