From 9ace51c5b4796927909be31e231fd7780c988382 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sat, 7 Oct 2017 11:29:48 +0800 Subject: [PATCH] crypto: skcipher - Fix crash on zero-length input MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 0cabf2af6f5ac3c88cb106c4e06087a5a39b8e1e upstream. The skcipher walk interface doesn't handle zero-length input properly as the old blkcipher walk interface did. This is due to the fact that the length check is done too late. This patch moves the length check forward so that it does the right thing. Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk...") Reported-by: Stephan Müller Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/skcipher.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/crypto/skcipher.c b/crypto/skcipher.c index 4faa0fd53b0c1..d5692e35fab1f 100644 --- a/crypto/skcipher.c +++ b/crypto/skcipher.c @@ -426,14 +426,9 @@ static int skcipher_copy_iv(struct skcipher_walk *walk) static int skcipher_walk_first(struct skcipher_walk *walk) { - walk->nbytes = 0; - if (WARN_ON_ONCE(in_irq())) return -EDEADLK; - if (unlikely(!walk->total)) - return 0; - walk->buffer = NULL; if (unlikely(((unsigned long)walk->iv & walk->alignmask))) { int err = skcipher_copy_iv(walk); @@ -452,10 +447,15 @@ static int skcipher_walk_skcipher(struct skcipher_walk *walk, { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + walk->total = req->cryptlen; + walk->nbytes = 0; + + if (unlikely(!walk->total)) + return 0; + scatterwalk_start(&walk->in, req->src); scatterwalk_start(&walk->out, req->dst); - walk->total = req->cryptlen; walk->iv = req->iv; walk->oiv = req->iv; @@ -509,6 +509,11 @@ static int skcipher_walk_aead_common(struct skcipher_walk *walk, struct crypto_aead *tfm = crypto_aead_reqtfm(req); int err; + walk->nbytes = 0; + + if (unlikely(!walk->total)) + return 0; + walk->flags &= ~SKCIPHER_WALK_PHYS; scatterwalk_start(&walk->in, req->src); -- 2.47.2