android-mainline/ANDROID-fscrypt-extend-max-allowed-size-of-fscrypt_provisioning-keys.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Mon, 2 Mar 2020 14:53:11 +0000
Subject: ANDROID: fscrypt: extend max allowed size of fscrypt_provisioning
 keys

Allow the size of fscrypt-provisioning keys to be up to
FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE rather than FSCRYPT_MAX_KEY_SIZE.

[maennich: This patch had been picked up from the merge conflict
resolution when merging f0d874414329 ("Merge tag 'fscrypt-for-linus' of
git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt") into android-mainline.
See 5cc45ee5951e ("Merge f0d874414329 ("Merge tag 'fscrypt-for-linus' of
git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt") into
android-mainline")]

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: If0cfafa34da08a559190928056086d3e772b29f8
---
 fs/crypto/keyring.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -513,8 +513,10 @@ static int fscrypt_provisioning_key_preparse(struct key_preparsed_payload *prep)
 {
 	const struct fscrypt_provisioning_key_payload *payload = prep->data;
 
+	BUILD_BUG_ON(FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE < FSCRYPT_MAX_KEY_SIZE);
+
 	if (prep->datalen < sizeof(*payload) + FSCRYPT_MIN_KEY_SIZE ||
-	    prep->datalen > sizeof(*payload) + FSCRYPT_MAX_KEY_SIZE)
+	    prep->datalen > sizeof(*payload) + FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE)
 		return -EINVAL;
 
 	if (payload->type != FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
@@ -678,9 +680,15 @@ int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg)
 		err = get_keyring_key(arg.key_id, arg.key_spec.type, &secret);
 		if (err)
 			goto out_wipe_secret;
+		err = -EINVAL;
+		if (!(arg.__flags & __FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED) &&
+		    secret.size > FSCRYPT_MAX_KEY_SIZE)
+			goto out_wipe_secret;
 	} else {
 		if (arg.raw_size < FSCRYPT_MIN_KEY_SIZE ||
-		    arg.raw_size > FSCRYPT_MAX_KEY_SIZE)
+		    arg.raw_size >
+		    ((arg.__flags & __FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED) ?
+		     FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE : FSCRYPT_MAX_KEY_SIZE))
 			return -EINVAL;
 		secret.size = arg.raw_size;
 		err = -EFAULT;