From c64cfb989f008eed2622e822e90f2fcabd49d605 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 9 Dec 2019 12:39:18 -0800 Subject: [PATCH] fscrypt: verify that the crypto_skcipher has the correct ivsize As a sanity check, verify that the allocated crypto_skcipher actually has the ivsize that fscrypt is assuming it has. This will always be the case unless there's a bug. But if there ever is such a bug (e.g. like there was in earlier versions of the ESSIV conversion patch [1]) it's preferable for it to be immediately obvious, and not rely on the ciphertext verification tests failing due to uninitialized IV bytes. [1] https://lkml.kernel.org/linux-crypto/20190702215517.GA69157@gmail.com/ Link: https://lore.kernel.org/r/20191209203918.225691-1-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/keysetup.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index c9f4fe955971..39fdea79e912 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -91,6 +91,10 @@ struct crypto_skcipher *fscrypt_allocate_skcipher(struct fscrypt_mode *mode, pr_info("fscrypt: %s using implementation \"%s\"\n", mode->friendly_name, crypto_skcipher_driver_name(tfm)); } + if (WARN_ON(crypto_skcipher_ivsize(tfm) != mode->ivsize)) { + err = -EINVAL; + goto err_free_tfm; + } crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize); if (err)