From: Eric Biggers <ebiggers@xxxxxxxxxx>
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@xxxxxxxxx/
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/crypto/keysetup.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index c9f4fe955971f..39fdea79e912f 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)
--
2.24.0.393.g34dc348eaf-goog
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