Commit fbe1a850 authored by Ondrej Mosnacek's avatar Ondrej Mosnacek Committed by Herbert Xu

crypto: lrw - Fix out-of bounds access on counter overflow

When the LRW block counter overflows, the current implementation returns
128 as the index to the precomputed multiplication table, which has 128
entries. This patch fixes it to return the correct value (127).

Fixes: 64470f1b ("[CRYPTO] lrw: Liskov Rivest Wagner, a tweakable narrow block cipher mode")
Cc: <stable@vger.kernel.org> # 2.6.20+
Reported-by: default avatarEric Biggers <ebiggers@kernel.org>
Signed-off-by: default avatarOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 331351f8
...@@ -143,7 +143,12 @@ static inline int get_index128(be128 *block) ...@@ -143,7 +143,12 @@ static inline int get_index128(be128 *block)
return x + ffz(val); return x + ffz(val);
} }
return x; /*
* If we get here, then x == 128 and we are incrementing the counter
* from all ones to all zeros. This means we must return index 127, i.e.
* the one corresponding to key2*{ 1,...,1 }.
*/
return 127;
} }
static int post_crypt(struct skcipher_request *req) static int post_crypt(struct skcipher_request *req)
......
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