From: Eric Biggers Date: Wed, 10 Apr 2019 06:46:30 +0000 (-0700) Subject: crypto: salsa20 - don't access already-freed walk.iv X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=edaf28e996af69222b2cb40455dbb5459c2b875a;p=openwrt%2Fstaging%2Fblogic.git crypto: salsa20 - don't access already-freed walk.iv 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 --- diff --git a/crypto/salsa20_generic.c b/crypto/salsa20_generic.c index 443fba09cbed..faed244be316 100644 --- a/crypto/salsa20_generic.c +++ b/crypto/salsa20_generic.c @@ -160,7 +160,7 @@ static int salsa20_crypt(struct skcipher_request *req) err = skcipher_walk_virt(&walk, req, false); - salsa20_init(state, ctx, walk.iv); + salsa20_init(state, ctx, req->iv); while (walk.nbytes > 0) { unsigned int nbytes = walk.nbytes;