From 3b5ddd5ea0165fc6b11e1e200a14797adb51b4cb Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 9 Apr 2019 23:46:30 -0700 Subject: [PATCH] crypto: salsa20 - don't access already-freed walk.iv commit edaf28e996af69222b2cb40455dbb5459c2b875a upstream. If the user-provided IV needs to be aligned to the algorithm's alignmask, then skcipher_walk_virt() copies the IV into a new aligned buffer walk.iv. But skcipher_walk_virt() can fail afterwards, and then if the caller unconditionally accesses walk.iv, it's a use-after-free. salsa20-generic doesn't set an alignmask, so currently it isn't affected by this despite unconditionally accessing walk.iv. However this is more subtle than desired, and it was actually broken prior to the alignmask being removed by commit b62b3db76f73 ("crypto: salsa20-generic - cleanup and convert to skcipher API"). Since salsa20-generic does not update the IV and does not need any IV alignment, update it to use req->iv instead of walk.iv. Fixes: 2407d60872dd ("[CRYPTO] salsa20: Salsa20 stream cipher") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/salsa20_generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/crypto/salsa20_generic.c b/crypto/salsa20_generic.c index 8c77bc7..df8fc0f 100644 --- a/crypto/salsa20_generic.c +++ b/crypto/salsa20_generic.c @@ -161,7 +161,7 @@ static int salsa20_crypt(struct skcipher_request *req) err = skcipher_walk_virt(&walk, req, true); - salsa20_init(state, ctx, walk.iv); + salsa20_init(state, ctx, req->iv); while (walk.nbytes > 0) { unsigned int nbytes = walk.nbytes; -- 2.7.4