From f659a818a42f4be9cffdc8bda4afca8b7cc5d98d Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Sun, 6 Dec 2015 02:51:37 +0100 Subject: [PATCH 1/1] crypto: skcipher - Copy iv from desc even for 0-len walks commit 70d906bc17500edfa9bdd8c8b7e59618c7911613 upstream. Some ciphers actually support encrypting zero length plaintexts. For example, many AEAD modes support this. The resulting ciphertext for those winds up being only the authentication tag, which is a result of the key, the iv, the additional data, and the fact that the plaintext had zero length. The blkcipher constructors won't copy the IV to the right place, however, when using a zero length input, resulting in some significant problems when ciphers call their initialization routines, only to find that the ->iv parameter is uninitialized. One such example of this would be using chacha20poly1305 with a zero length input, which then calls chacha20, which calls the key setup routine, which eventually OOPSes due to the uninitialized ->iv member. Signed-off-by: Jason A. Donenfeld Signed-off-by: Herbert Xu [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- crypto/ablkcipher.c | 2 +- crypto/blkcipher.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c index d53a30b7f703..6eb6eb122502 100644 --- a/crypto/ablkcipher.c +++ b/crypto/ablkcipher.c @@ -280,12 +280,12 @@ static int ablkcipher_walk_first(struct ablkcipher_request *req, if (WARN_ON_ONCE(in_irq())) return -EDEADLK; + walk->iv = req->info; walk->nbytes = walk->total; if (unlikely(!walk->total)) return 0; walk->iv_buffer = NULL; - walk->iv = req->info; if (unlikely(((unsigned long)walk->iv & alignmask))) { int err = ablkcipher_copy_iv(walk, tfm, alignmask); if (err) diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c index 04f0f388adf1..3041504370b1 100644 --- a/crypto/blkcipher.c +++ b/crypto/blkcipher.c @@ -329,12 +329,12 @@ static int blkcipher_walk_first(struct blkcipher_desc *desc, if (WARN_ON_ONCE(in_irq())) return -EDEADLK; + walk->iv = desc->info; walk->nbytes = walk->total; if (unlikely(!walk->total)) return 0; walk->buffer = NULL; - walk->iv = desc->info; if (unlikely(((unsigned long)walk->iv & alignmask))) { int err = blkcipher_copy_iv(walk, tfm, alignmask); if (err) -- 2.39.2