crypto: sm3 - fix undefined shift by >= width of value

sm3_compress() calls rol32() with shift >= 32, which causes undefined
behavior.  This is easily detected by enabling CONFIG_UBSAN.

Explicitly AND with 31 to make the behavior well defined.

Fixes: 4f0fc1600edb ("crypto: sm3 - add OSCCA SM3 secure hash")
Cc: <stable@vger.kernel.org> # v4.15+
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/sm3_generic.c b/crypto/sm3_generic.c
index 9a5c60f..c0cf87a 100644 (file)
--- a/crypto/sm3_generic.c
+++ b/crypto/sm3_generic.c
@@ -100,7 +100,7 @@ static void sm3_compress(u32 *w, u32 *wt, u32 *m)
 
        for (i = 0; i <= 63; i++) {
 
-               ss1 = rol32((rol32(a, 12) + e + rol32(t(i), i)), 7);
+               ss1 = rol32((rol32(a, 12) + e + rol32(t(i), i & 31)), 7);
 
                ss2 = ss1 ^ rol32(a, 12);