From 0cabf2af6f5ac3c88cb106c4e06087a5a39b8e1e 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 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...") Cc: Reported-by: Stephan Müller Signed-off-by: Herbert Xu --- crypto/skcipher.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/crypto/skcipher.c b/crypto/skcipher.c index 4faa0fd53b0c..d5692e35fab1 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); -- 2.20.1