* [PATCH] fscrypto: require write access to mount to set encryption policy
@ 2016-09-20 0:49 Eric Biggers
0 siblings, 0 replies; 3+ messages in thread
From: Eric Biggers @ 2016-09-20 0:49 UTC (permalink / raw)
To: stable; +Cc: tytso, jaegeuk, Eric Biggers
commit ba63f23d69a3a10e7e527a02702023da68ef8a6d upstream, backported to
fs/ext4/ioctl.c for pre-4.8 kernels.
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.
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
fs/ext4/ioctl.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 28cc412..64eddc5 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -782,7 +782,13 @@ 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
--
2.8.0.rc3.226.g39d4020
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] fscrypto: require write access to mount to set encryption policy
@ 2017-10-24 23:32 Eric Biggers
2017-10-25 9:42 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: Eric Biggers @ 2017-10-24 23:32 UTC (permalink / raw)
To: stable; +Cc: Jaegeuk Kim, Eric Biggers, Theodore Ts'o
From: Eric Biggers <ebiggers@google.com>
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>
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>
---
fs/f2fs/file.c | 6 ++++++
1 file changed, 6 insertions(+)
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;
--
2.15.0.rc0.271.g36b669edcc-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fscrypto: require write access to mount to set encryption policy
2017-10-24 23:32 [PATCH] fscrypto: require write access to mount to set encryption policy Eric Biggers
@ 2017-10-25 9:42 ` Greg KH
0 siblings, 0 replies; 3+ messages in thread
From: Greg KH @ 2017-10-25 9:42 UTC (permalink / raw)
To: Eric Biggers; +Cc: stable, Jaegeuk Kim, Eric Biggers, Theodore Ts'o
On Tue, Oct 24, 2017 at 04:32:16PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> 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.]
Good catch, thanks for the patch.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
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