Commit fbe1a850 authored Sep 13, 2018 by Ondrej Mosnacek Committed by Herbert Xu Sep 21, 2018

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: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 331351f8

crypto/lrw.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -143,7 +143,12 @@ static inline int get_index128(be128 *block)
		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)

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