From: Eric Biggers ebiggers@google.com
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 ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- crypto/salsa20_generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/crypto/salsa20_generic.c +++ b/crypto/salsa20_generic.c @@ -161,7 +161,7 @@ static int salsa20_crypt(struct skcipher
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;