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| author | Eric Biggers <ebiggers@google.com> | 2016-09-09 00:20:38 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-27 11:23:18 +0300 |
| commit | 1bb1d4252d1ede47afea054979fb9d95fc891743 (patch) | |
| tree | 91902fba6512e6984b6baed007b1a069a62214a0 | |
| parent | 8a004caec12bf241e567e3640401256cc9bc2e45 (diff) | |
| download | linux-1bb1d4252d1ede47afea054979fb9d95fc891743.tar.xz | |
fscrypto: require write access to mount to set encryption policy
commit ba63f23d69a3a10e7e527a02702023da68ef8a6d upstream.
[Please apply to 4.4-stable. Note: this was already backported, but
only to ext4; it was missed that it should go to f2fs as well. This is
needed to make xfstest generic/395 pass on f2fs.]
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>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/f2fs/file.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 4b449d263333..01eed94b01ea 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1541,12 +1541,18 @@ static int f2fs_ioc_set_encryption_policy(struct file *filp, unsigned long arg) sizeof(policy))) return -EFAULT; + err = mnt_want_write_file(filp); + if (err) + return err; + mutex_lock(&inode->i_mutex); err = f2fs_process_policy(&policy, inode); mutex_unlock(&inode->i_mutex); + mnt_drop_write_file(filp); + return err; #else return -EOPNOTSUPP; |