linux-stable.git/fs/ext4, branch v4.4.67 Linux kernel stable tree ext4/fscrypto: avoid RCU lookup in d_revalidate 2017-05-08T05:46:02+00:00 Jaegeuk Kim jaegeuk@kernel.org 2016-04-12T23:05:36+00:00 16fb859f9b2bb246a18b4d0edc605774193c33b7 commit 03a8bb0e53d9562276045bdfcf2b5de2e4cff5a1 upstream. As Al pointed, d_revalidate should return RCU lookup before using d_inode. This was originally introduced by: commit 34286d666230 ("fs: rcu-walk aware d_revalidate method"). Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 03a8bb0e53d9562276045bdfcf2b5de2e4cff5a1 upstream.

As Al pointed, d_revalidate should return RCU lookup before using d_inode.
This was originally introduced by:
commit 34286d666230 ("fs: rcu-walk aware d_revalidate method").

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4 crypto: use dget_parent() in ext4_d_revalidate() 2017-05-08T05:46:02+00:00 Theodore Ts'o tytso@mit.edu 2016-03-26T20:15:42+00:00 41948f88a521b95e8abc793602015a6d45f52a06 commit 3d43bcfef5f0548845a425365011c499875491b0 upstream. This avoids potential problems caused by a race where the inode gets renamed out from its parent directory and the parent directory is deleted while ext4_d_revalidate() is running. Fixes: 28b4c263961c Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3d43bcfef5f0548845a425365011c499875491b0 upstream.

This avoids potential problems caused by a race where the inode gets
renamed out from its parent directory and the parent directory is
deleted while ext4_d_revalidate() is running.

Fixes: 28b4c263961c
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4 crypto: revalidate dentry after adding or removing the key 2017-05-08T05:46:02+00:00 Theodore Ts'o tytso@mit.edu 2016-02-08T00:35:05+00:00 2faff9d1dfc560da3bfba6a8ab0c30246fd6c1cb commit 28b4c263961c47da84ed8b5be0b5116bad1133eb upstream. Add a validation check for dentries for encrypted directory to make sure we're not caching stale data after a key has been added or removed. Also check to make sure that status of the encryption key is updated when readdir(2) is executed. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 28b4c263961c47da84ed8b5be0b5116bad1133eb upstream.

Add a validation check for dentries for encrypted directory to make
sure we're not caching stale data after a key has been added or removed.

Also check to make sure that status of the encryption key is updated
when readdir(2) is executed.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: require encryption feature for EXT4_IOC_SET_ENCRYPTION_POLICY 2017-05-08T05:46:02+00:00 Richard Weinberger richard@nod.at 2016-09-30T05:49:55+00:00 e2968fb8e7980dccc199dac2593ad476db20969f commit 9a200d075e5d05be1fcad4547a0f8aee4e2f9a04 upstream. ...otherwise an user can enable encryption for certain files even when the filesystem is unable to support it. Such a case would be a filesystem created by mkfs.ext4's default settings, 1KiB block size. Ext4 supports encyption only when block size is equal to PAGE_SIZE. But this constraint is only checked when the encryption feature flag is set. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9a200d075e5d05be1fcad4547a0f8aee4e2f9a04 upstream.

...otherwise an user can enable encryption for certain files even
when the filesystem is unable to support it.
Such a case would be a filesystem created by mkfs.ext4's default
settings, 1KiB block size. Ext4 supports encyption only when block size
is equal to PAGE_SIZE.
But this constraint is only checked when the encryption feature flag
is set.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea() 2017-05-03T04:19:48+00:00 Theodore Ts'o tytso@mit.edu 2016-03-22T20:13:15+00:00 28320756e78b3e8f1520bc1c34b23a3df452569e commit 9e92f48c34eb2b9af9d12f892e2fe1fce5e8ce35 upstream. We aren't checking to see if the in-inode extended attribute is corrupted before we try to expand the inode's extra isize fields. This can lead to potential crashes caused by the BUG_ON() check in ext4_xattr_shift_entries(). Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9e92f48c34eb2b9af9d12f892e2fe1fce5e8ce35 upstream.

We aren't checking to see if the in-inode extended attribute is
corrupted before we try to expand the inode's extra isize fields.

This can lead to potential crashes caused by the BUG_ON() check in
ext4_xattr_shift_entries().

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: fix inode checksum calculation problem if i_extra_size is small 2017-04-21T07:30:07+00:00 Daeho Jeong daeho.jeong@samsung.com 2016-12-01T16:49:12+00:00 51f8d95c89b4aa74e591015d076d2775d9286704 commit 05ac5aa18abd7db341e54df4ae2b4c98ea0e43b7 upstream. We've fixed the race condition problem in calculating ext4 checksum value in commit b47820edd163 ("ext4: avoid modifying checksum fields directly during checksum veficationon"). However, by this change, when calculating the checksum value of inode whose i_extra_size is less than 4, we couldn't calculate the checksum value in a proper way. This problem was found and reported by Nix, Thank you. Reported-by: Nix <nix@esperi.org.uk> Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com> Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 05ac5aa18abd7db341e54df4ae2b4c98ea0e43b7 upstream.

We've fixed the race condition problem in calculating ext4 checksum
value in commit b47820edd163 ("ext4: avoid modifying checksum fields
directly during checksum veficationon"). However, by this change,
when calculating the checksum value of inode whose i_extra_size is
less than 4, we couldn't calculate the checksum value in a proper way.
This problem was found and reported by Nix, Thank you.

Reported-by: Nix <nix@esperi.org.uk>
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypt: remove broken support for detecting keyring key revocation 2017-03-31T07:49:54+00:00 Eric Biggers ebiggers@google.com 2017-02-21T23:07:11+00:00 7a5202190810dde1467718235c1f650fcf57592a commit 1b53cf9815bb4744958d41f3795d5d5a1d365e2d upstream. Filesystem encryption ostensibly supported revoking a keyring key that had been used to "unlock" encrypted files, causing those files to become "locked" again. This was, however, buggy for several reasons, the most severe of which was that when key revocation happened to be detected for an inode, its fscrypt_info was immediately freed, even while other threads could be using it for encryption or decryption concurrently. This could be exploited to crash the kernel or worse. This patch fixes the use-after-free by removing the code which detects the keyring key having been revoked, invalidated, or expired. Instead, an encrypted inode that is "unlocked" now simply remains unlocked until it is evicted from memory. Note that this is no worse than the case for block device-level encryption, e.g. dm-crypt, and it still remains possible for a privileged user to evict unused pages, inodes, and dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by simply unmounting the filesystem. In fact, one of those actions was already needed anyway for key revocation to work even somewhat sanely. This change is not expected to break any applications. In the future I'd like to implement a real API for fscrypt key revocation that interacts sanely with ongoing filesystem operations --- waiting for existing operations to complete and blocking new operations, and invalidating and sanitizing key material and plaintext from the VFS caches. But this is a hard problem, and for now this bug must be fixed. This bug affected almost all versions of ext4, f2fs, and ubifs encryption, and it was potentially reachable in any kernel configured with encryption support (CONFIG_EXT4_ENCRYPTION=y, CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or CONFIG_UBIFS_FS_ENCRYPTION=y). Note that older kernels did not use the shared fs/crypto/ code, but due to the potential security implications of this bug, it may still be worthwhile to backport this fix to them. Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1b53cf9815bb4744958d41f3795d5d5a1d365e2d upstream.

Filesystem encryption ostensibly supported revoking a keyring key that
had been used to "unlock" encrypted files, causing those files to become
"locked" again.  This was, however, buggy for several reasons, the most
severe of which was that when key revocation happened to be detected for
an inode, its fscrypt_info was immediately freed, even while other
threads could be using it for encryption or decryption concurrently.
This could be exploited to crash the kernel or worse.

This patch fixes the use-after-free by removing the code which detects
the keyring key having been revoked, invalidated, or expired.  Instead,
an encrypted inode that is "unlocked" now simply remains unlocked until
it is evicted from memory.  Note that this is no worse than the case for
block device-level encryption, e.g. dm-crypt, and it still remains
possible for a privileged user to evict unused pages, inodes, and
dentries by running 'sync; echo 3 > /proc/sys/vm/drop_caches', or by
simply unmounting the filesystem.  In fact, one of those actions was
already needed anyway for key revocation to work even somewhat sanely.
This change is not expected to break any applications.

In the future I'd like to implement a real API for fscrypt key
revocation that interacts sanely with ongoing filesystem operations ---
waiting for existing operations to complete and blocking new operations,
and invalidating and sanitizing key material and plaintext from the VFS
caches.  But this is a hard problem, and for now this bug must be fixed.

This bug affected almost all versions of ext4, f2fs, and ubifs
encryption, and it was potentially reachable in any kernel configured
with encryption support (CONFIG_EXT4_ENCRYPTION=y,
CONFIG_EXT4_FS_ENCRYPTION=y, CONFIG_F2FS_FS_ENCRYPTION=y, or
CONFIG_UBIFS_FS_ENCRYPTION=y).  Note that older kernels did not use the
shared fs/crypto/ code, but due to the potential security implications
of this bug, it may still be worthwhile to backport this fix to them.

Fixes: b7236e21d55f ("ext4 crypto: reorganize how we store keys in the inode")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: mark inode dirty after converting inline directory 2017-03-30T07:35:17+00:00 Eric Biggers ebiggers@google.com 2017-03-15T18:52:02+00:00 27d9bf096406439ce406c82291cfe09c6653f94c commit b9cf625d6ecde0d372e23ae022feead72b4228a6 upstream. If ext4_convert_inline_data() was called on a directory with inline data, the filesystem was left in an inconsistent state (as considered by e2fsck) because the file size was not increased to cover the new block. This happened because the inode was not marked dirty after i_disksize was updated. Fix this by marking the inode dirty at the end of ext4_finish_convert_inline_dir(). This bug was probably not noticed before because most users mark the inode dirty afterwards for other reasons. But if userspace executed FS_IOC_SET_ENCRYPTION_POLICY with invalid parameters, as exercised by 'kvm-xfstests -c adv generic/396', then the inode was never marked dirty after updating i_disksize. Fixes: 3c47d54170b6a678875566b1b8d6dcf57904e49b Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b9cf625d6ecde0d372e23ae022feead72b4228a6 upstream.

If ext4_convert_inline_data() was called on a directory with inline
data, the filesystem was left in an inconsistent state (as considered by
e2fsck) because the file size was not increased to cover the new block.
This happened because the inode was not marked dirty after i_disksize
was updated.  Fix this by marking the inode dirty at the end of
ext4_finish_convert_inline_dir().

This bug was probably not noticed before because most users mark the
inode dirty afterwards for other reasons.  But if userspace executed
FS_IOC_SET_ENCRYPTION_POLICY with invalid parameters, as exercised by
'kvm-xfstests -c adv generic/396', then the inode was never marked dirty
after updating i_disksize.

Fixes: 3c47d54170b6a678875566b1b8d6dcf57904e49b
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: fix fencepost in s_first_meta_bg validation 2017-03-26T10:13:20+00:00 Theodore Ts'o tytso@mit.edu 2017-02-15T06:26:39+00:00 5fa513cb07213608907d4daa123b81e5a32d13e0 commit 2ba3e6e8afc9b6188b471f27cf2b5e3cf34e7af2 upstream. It is OK for s_first_meta_bg to be equal to the number of block group descriptor blocks. (It rarely happens, but it shouldn't cause any problems.) https://bugzilla.kernel.org/show_bug.cgi?id=194567 Fixes: 3a4b77cd47bb837b8557595ec7425f281f2ca1fe Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2ba3e6e8afc9b6188b471f27cf2b5e3cf34e7af2 upstream.

It is OK for s_first_meta_bg to be equal to the number of block group
descriptor blocks.  (It rarely happens, but it shouldn't cause any
problems.)

https://bugzilla.kernel.org/show_bug.cgi?id=194567

Fixes: 3a4b77cd47bb837b8557595ec7425f281f2ca1fe
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fscrypto: lock inode while setting encryption policy 2017-03-22T11:04:18+00:00 Eric Biggers ebiggers@google.com 2016-10-15T13:48:50+00:00 3a19419c50c6ee386ca6d22a23acc2df51583d3d commit 8906a8223ad4909b391c5628f7991ebceda30e52 upstream. i_rwsem needs to be acquired while setting an encryption policy so that concurrent calls to FS_IOC_SET_ENCRYPTION_POLICY are correctly serialized (especially the ->get_context() + ->set_context() pair), and so that new files cannot be created in the directory during or after the ->empty_dir() check. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Richard Weinberger <richard@nod.at> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8906a8223ad4909b391c5628f7991ebceda30e52 upstream.

i_rwsem needs to be acquired while setting an encryption policy so that
concurrent calls to FS_IOC_SET_ENCRYPTION_POLICY are correctly
serialized (especially the ->get_context() + ->set_context() pair), and
so that new files cannot be created in the directory during or after the
->empty_dir() check.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Richard Weinberger <richard@nod.at>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>