diff options
| author | Eric Biggers <ebiggers@google.com> | 2016-09-08 14:20:38 -0700 |
|---|---|---|
| committer | Sasha Levin <alexander.levin@verizon.com> | 2016-10-02 20:44:37 -0400 |
| commit | 41beb77f7e59e17d675f159ae83c34b6545b7316 (patch) | |
| tree | fd1fdb687df6fffc3b943acf81bcd90b9a9186d4 | |
| parent | 08ac15d0e46bddb8dc9ae9bd939e844d7c2451b9 (diff) | |
| download | lwn-41beb77f7e59e17d675f159ae83c34b6545b7316.tar.gz lwn-41beb77f7e59e17d675f159ae83c34b6545b7316.zip | |
fscrypto: require write access to mount to set encryption policy
[ Upstream commit ba63f23d69a3a10e7e527a02702023da68ef8a6d ]
Since setting an encryption policy requires writing metadata to the
filesystem, it should be guarded by mnt_want_write/mnt_drop_write.
Otherwise, a user could cause a write to a frozen or readonly
filesystem. This was handled correctly by f2fs but not by ext4. Make
fscrypt_process_policy() handle it rather than relying on the filesystem
to get it right.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: stable@vger.kernel.org # 4.1+; check fs/{ext4,f2fs}
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
| -rw-r--r-- | fs/ext4/ioctl.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 2cb9e178d1c5..4196aa567784 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -637,7 +637,13 @@ resizefs_out: goto encryption_policy_out; } + err = mnt_want_write_file(filp); + if (err) + goto encryption_policy_out; + err = ext4_process_policy(&policy, inode); + + mnt_drop_write_file(filp); encryption_policy_out: return err; #else |