linux-stable.git/fs, branch v4.4.59 Linux kernel stable tree 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 This patch fixes the use-after-free by removing the code which detects the keyring key having been revoked, invalidated, or expired.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>
xfs: clear _XBF_PAGES from buffers when readahead page 2017-03-30T07:35:19+00:00 Darrick J. Wong darrick.wong@oracle.com 2017-01-26T04:24:57+00:00 6d43e485e0067b682466eb4e3aff8ff9a6822966 commit 2aa6ba7b5ad3189cc27f14540aa2f57f0ed8df4b upstream. If we try to allocate memory pages to back an xfs_buf that we're trying to read, it's possible that we'll be so short on memory that the page allocation fails. For a blocking read we'll just wait, but for readahead we simply dump all the pages we've collected so far. Unfortunately, after dumping the pages we neglect to clear the _XBF_PAGES state, which means that the subsequent call to xfs_buf_free thinks that b_pages still points to pages we own. It then double-frees the b_pages pages. This results in screaming about negative page refcounts from the memory manager, which xfs oughtn't be triggering. To reproduce this case, mount a filesystem where the size of the inodes far outweighs the availalble memory (a ~500M inode filesystem on a VM with 300MB memory did the trick here) and run bulkstat in parallel with other memory eating processes to put a huge load on the system. The "check summary" phase of xfs_scrub also works for this purpose. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Cc: Ivan Kozik <ivan@ludios.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2aa6ba7b5ad3189cc27f14540aa2f57f0ed8df4b upstream.

If we try to allocate memory pages to back an xfs_buf that we're trying
to read, it's possible that we'll be so short on memory that the page
allocation fails.  For a blocking read we'll just wait, but for
readahead we simply dump all the pages we've collected so far.

Unfortunately, after dumping the pages we neglect to clear the
_XBF_PAGES state, which means that the subsequent call to xfs_buf_free
thinks that b_pages still points to pages we own.  It then double-frees
the b_pages pages.

This results in screaming about negative page refcounts from the memory
manager, which xfs oughtn't be triggering.  To reproduce this case,
mount a filesystem where the size of the inodes far outweighs the
availalble memory (a ~500M inode filesystem on a VM with 300MB memory
did the trick here) and run bulkstat in parallel with other memory
eating processes to put a huge load on the system.  The "check summary"
phase of xfs_scrub also works for this purpose.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Cc: Ivan Kozik <ivan@ludios.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xfs: fix up xfs_swap_extent_forks inline extent handling 2017-03-30T07:35:18+00:00 Eric Sandeen sandeen@sandeen.net 2016-11-08T01:55:18+00:00 7922c1becb36b61827a24ee32ffe7c39cf444efb commit 4dfce57db6354603641132fac3c887614e3ebe81 upstream. There have been several reports over the years of NULL pointer dereferences in xfs_trans_log_inode during xfs_fsr processes, when the process is doing an fput and tearing down extents on the temporary inode, something like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 PID: 29439 TASK: ffff880550584fa0 CPU: 6 COMMAND: "xfs_fsr" [exception RIP: xfs_trans_log_inode+0x10] #9 [ffff8800a57bbbe0] xfs_bunmapi at ffffffffa037398e [xfs] #10 [ffff8800a57bbce8] xfs_itruncate_extents at ffffffffa0391b29 [xfs] #11 [ffff8800a57bbd88] xfs_inactive_truncate at ffffffffa0391d0c [xfs] #12 [ffff8800a57bbdb8] xfs_inactive at ffffffffa0392508 [xfs] #13 [ffff8800a57bbdd8] xfs_fs_evict_inode at ffffffffa035907e [xfs] #14 [ffff8800a57bbe00] evict at ffffffff811e1b67 #15 [ffff8800a57bbe28] iput at ffffffff811e23a5 #16 [ffff8800a57bbe58] dentry_kill at ffffffff811dcfc8 #17 [ffff8800a57bbe88] dput at ffffffff811dd06c #18 [ffff8800a57bbea8] __fput at ffffffff811c823b #19 [ffff8800a57bbef0] ____fput at ffffffff811c846e #20 [ffff8800a57bbf00] task_work_run at ffffffff81093b27 #21 [ffff8800a57bbf30] do_notify_resume at ffffffff81013b0c #22 [ffff8800a57bbf50] int_signal at ffffffff8161405d As it turns out, this is because the i_itemp pointer, along with the d_ops pointer, has been overwritten with zeros when we tear down the extents during truncate. When the in-core inode fork on the temporary inode used by xfs_fsr was originally set up during the extent swap, we mistakenly looked at di_nextents to determine whether all extents fit inline, but this misses extents generated by speculative preallocation; we should be using if_bytes instead. This mistake corrupts the in-memory inode, and code in xfs_iext_remove_inline eventually gets bad inputs, causing it to memmove and memset incorrect ranges; this became apparent because the two values in ifp->if_u2.if_inline_ext[1] contained what should have been in d_ops and i_itemp; they were memmoved due to incorrect array indexing and then the original locations were zeroed with memset, again due to an array overrun. Fix this by properly using i_df.if_bytes to determine the number of extents, not di_nextents. Thanks to dchinner for looking at this with me and spotting the root cause. [nborisov: backported to 4.4] Cc: stable@vger.kernel.org Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -- fs/xfs/xfs_bmap_util.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) 
commit 4dfce57db6354603641132fac3c887614e3ebe81 upstream.

There have been several reports over the years of NULL pointer
dereferences in xfs_trans_log_inode during xfs_fsr processes,
when the process is doing an fput and tearing down extents
on the temporary inode, something like:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
PID: 29439  TASK: ffff880550584fa0  CPU: 6   COMMAND: "xfs_fsr"
    [exception RIP: xfs_trans_log_inode+0x10]
 #9 [ffff8800a57bbbe0] xfs_bunmapi at ffffffffa037398e [xfs]
#10 [ffff8800a57bbce8] xfs_itruncate_extents at ffffffffa0391b29 [xfs]
#11 [ffff8800a57bbd88] xfs_inactive_truncate at ffffffffa0391d0c [xfs]
#12 [ffff8800a57bbdb8] xfs_inactive at ffffffffa0392508 [xfs]
#13 [ffff8800a57bbdd8] xfs_fs_evict_inode at ffffffffa035907e [xfs]
#14 [ffff8800a57bbe00] evict at ffffffff811e1b67
#15 [ffff8800a57bbe28] iput at ffffffff811e23a5
#16 [ffff8800a57bbe58] dentry_kill at ffffffff811dcfc8
#17 [ffff8800a57bbe88] dput at ffffffff811dd06c
#18 [ffff8800a57bbea8] __fput at ffffffff811c823b
#19 [ffff8800a57bbef0] ____fput at ffffffff811c846e
#20 [ffff8800a57bbf00] task_work_run at ffffffff81093b27
#21 [ffff8800a57bbf30] do_notify_resume at ffffffff81013b0c
#22 [ffff8800a57bbf50] int_signal at ffffffff8161405d

As it turns out, this is because the i_itemp pointer, along
with the d_ops pointer, has been overwritten with zeros
when we tear down the extents during truncate.  When the in-core
inode fork on the temporary inode used by xfs_fsr was originally
set up during the extent swap, we mistakenly looked at di_nextents
to determine whether all extents fit inline, but this misses extents
generated by speculative preallocation; we should be using if_bytes
instead.

This mistake corrupts the in-memory inode, and code in
xfs_iext_remove_inline eventually gets bad inputs, causing
it to memmove and memset incorrect ranges; this became apparent
because the two values in ifp->if_u2.if_inline_ext[1] contained
what should have been in d_ops and i_itemp; they were memmoved due
to incorrect array indexing and then the original locations
were zeroed with memset, again due to an array overrun.

Fix this by properly using i_df.if_bytes to determine the number
of extents, not di_nextents.

Thanks to dchinner for looking at this with me and spotting the
root cause.

[nborisov: backported to 4.4]

Cc: stable@vger.kernel.org
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--
 fs/xfs/xfs_bmap_util.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
xfs: don't allow di_size with high bit set 2017-03-30T07:35:18+00:00 Darrick J. Wong darrick.wong@oracle.com 2016-12-05T01:38:38+00:00 c4cf86f69597d4547a736e3edd5b88ae61b68fa2 commit ef388e2054feedaeb05399ed654bdb06f385d294 upstream. The on-disk field di_size is used to set i_size, which is a signed integer of loff_t. If the high bit of di_size is set, we'll end up with a negative i_size, which will cause all sorts of problems. Since the VFS won't let us create a file with such length, we should catch them here in the verifier too. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Cc: Nikolay Borisov <n.borisov.lkml@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ef388e2054feedaeb05399ed654bdb06f385d294 upstream.

The on-disk field di_size is used to set i_size, which is a signed
integer of loff_t.  If the high bit of di_size is set, we'll end up with
a negative i_size, which will cause all sorts of problems.  Since the
VFS won't let us create a file with such length, we should catch them
here in the verifier too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.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>
gfs2: Avoid alignment hole in struct lm_lockname 2017-03-26T10:13:19+00:00 Andreas Gruenbacher agruenba@redhat.com 2017-03-06T17:58:42+00:00 e08f608ab4288f4192a504e6c94dd7c9c931dad8 commit 28ea06c46fbcab63fd9a55531387b7928a18a590 upstream. Commit 88ffbf3e03 switches to using rhashtables for glocks, hashing over the entire struct lm_lockname instead of its individual fields. On some architectures, struct lm_lockname contains a hole of uninitialized memory due to alignment rules, which now leads to incorrect hash values. Get rid of that hole. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 28ea06c46fbcab63fd9a55531387b7928a18a590 upstream.

Commit 88ffbf3e03 switches to using rhashtables for glocks, hashing over
the entire struct lm_lockname instead of its individual fields.  On some
architectures, struct lm_lockname contains a hole of uninitialized
memory due to alignment rules, which now leads to incorrect hash values.
Get rid of that hole.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
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>
fscrypt: fix renaming and linking special files 2017-03-22T11:04:18+00:00 Eric Biggers ebiggers@google.com 2016-12-19T22:20:13+00:00 fd74e8d258da9f9678da6bf88a0b02b2c1b71d0c commit 42d97eb0ade31e1bc537d086842f5d6e766d9d51 upstream. Attempting to link a device node, named pipe, or socket file into an encrypted directory through rename(2) or link(2) always failed with EPERM. This happened because fscrypt_has_permitted_context() saw that the file was unencrypted and forbid creating the link. This behavior was unexpected because such files are never encrypted; only regular files, directories, and symlinks can be encrypted. To fix this, make fscrypt_has_permitted_context() always return true on special files. This will be covered by a test in my encryption xfstests patchset. Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support") Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Richard Weinberger <richard@nod.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 42d97eb0ade31e1bc537d086842f5d6e766d9d51 upstream.

Attempting to link a device node, named pipe, or socket file into an
encrypted directory through rename(2) or link(2) always failed with
EPERM.  This happened because fscrypt_has_permitted_context() saw that
the file was unencrypted and forbid creating the link.  This behavior
was unexpected because such files are never encrypted; only regular
files, directories, and symlinks can be encrypted.

To fix this, make fscrypt_has_permitted_context() always return true on
special files.

This will be covered by a test in my encryption xfstests patchset.

Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: don't BUG when truncating encrypted inodes on the orphan list 2017-03-18T11:09:58+00:00 Theodore Ts'o tytso@mit.edu 2017-02-14T16:31:15+00:00 1c5265be54d32ee21128137ccdb6ecbab0458f07 commit 0d06863f903ac5f4f6efb0273079d27de3e53a28 upstream. Fix a BUG when the kernel tries to mount a file system constructed as follows: echo foo > foo.txt mke2fs -Fq -t ext4 -O encrypt foo.img 100 debugfs -w foo.img << EOF write foo.txt a set_inode_field a i_flags 0x80800 set_super_value s_last_orphan 12 quit EOF root@kvm-xfstests:~# mount -o loop foo.img /mnt [ 160.238770] ------------[ cut here ]------------ [ 160.240106] kernel BUG at /usr/projects/linux/ext4/fs/ext4/inode.c:3874! [ 160.240106] invalid opcode: 0000 [#1] SMP [ 160.240106] Modules linked in: [ 160.240106] CPU: 0 PID: 2547 Comm: mount Tainted: G W 4.10.0-rc3-00034-gcdd33b941b67 #227 [ 160.240106] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1 04/01/2014 [ 160.240106] task: f4518000 task.stack: f47b6000 [ 160.240106] EIP: ext4_block_zero_page_range+0x1a7/0x2b4 [ 160.240106] EFLAGS: 00010246 CPU: 0 [ 160.240106] EAX: 00000001 EBX: f7be4b50 ECX: f47b7dc0 EDX: 00000007 [ 160.240106] ESI: f43b05a8 EDI: f43babec EBP: f47b7dd0 ESP: f47b7dac [ 160.240106] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 160.240106] CR0: 80050033 CR2: bfd85b08 CR3: 34a00680 CR4: 000006f0 [ 160.240106] Call Trace: [ 160.240106] ext4_truncate+0x1e9/0x3e5 [ 160.240106] ext4_fill_super+0x286f/0x2b1e [ 160.240106] ? set_blocksize+0x2e/0x7e [ 160.240106] mount_bdev+0x114/0x15f [ 160.240106] ext4_mount+0x15/0x17 [ 160.240106] ? ext4_calculate_overhead+0x39d/0x39d [ 160.240106] mount_fs+0x58/0x115 [ 160.240106] vfs_kern_mount+0x4b/0xae [ 160.240106] do_mount+0x671/0x8c3 [ 160.240106] ? _copy_from_user+0x70/0x83 [ 160.240106] ? strndup_user+0x31/0x46 [ 160.240106] SyS_mount+0x57/0x7b [ 160.240106] do_int80_syscall_32+0x4f/0x61 [ 160.240106] entry_INT80_32+0x2f/0x2f [ 160.240106] EIP: 0xb76b919e [ 160.240106] EFLAGS: 00000246 CPU: 0 [ 160.240106] EAX: ffffffda EBX: 08053838 ECX: 08052188 EDX: 080537e8 [ 160.240106] ESI: c0ed0000 EDI: 00000000 EBP: 080537e8 ESP: bfa13660 [ 160.240106] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b [ 160.240106] Code: 59 8b 00 a8 01 0f 84 09 01 00 00 8b 07 66 25 00 f0 66 3d 00 80 75 61 89 f8 e8 3e e2 ff ff 84 c0 74 56 83 bf 48 02 00 00 00 75 02 <0f> 0b 81 7d e8 00 10 00 00 74 02 0f 0b 8b 43 04 8b 53 08 31 c9 [ 160.240106] EIP: ext4_block_zero_page_range+0x1a7/0x2b4 SS:ESP: 0068:f47b7dac [ 160.317241] ---[ end trace d6a773a375c810a5 ]--- The problem is that when the kernel tries to truncate an inode in ext4_truncate(), it tries to clear any on-disk data beyond i_size. Without the encryption key, it can't do that, and so it triggers a BUG. E2fsck does *not* provide this service, and in practice most file systems have their orphan list processed by e2fsck, so to avoid crashing, this patch skips this step if we don't have access to the encryption key (which is the case when processing the orphan list; in all other cases, we will have the encryption key, or the kernel wouldn't have allowed the file to be opened). An open question is whether the fact that e2fsck isn't clearing the bytes beyond i_size causing problems --- and if we've lived with it not doing it for so long, can we drop this from the kernel replay of the orphan list in all cases (not just when we don't have the key for encrypted inodes). Addresses-Google-Bug: #35209576 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 0d06863f903ac5f4f6efb0273079d27de3e53a28 upstream.

Fix a BUG when the kernel tries to mount a file system constructed as
follows:

echo foo > foo.txt
mke2fs -Fq -t ext4 -O encrypt foo.img 100
debugfs -w foo.img << EOF
write foo.txt a
set_inode_field a i_flags 0x80800
set_super_value s_last_orphan 12
quit
EOF

root@kvm-xfstests:~# mount -o loop foo.img /mnt
[  160.238770] ------------[ cut here ]------------
[  160.240106] kernel BUG at /usr/projects/linux/ext4/fs/ext4/inode.c:3874!
[  160.240106] invalid opcode: 0000 [#1] SMP
[  160.240106] Modules linked in:
[  160.240106] CPU: 0 PID: 2547 Comm: mount Tainted: G        W       4.10.0-rc3-00034-gcdd33b941b67 #227
[  160.240106] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1 04/01/2014
[  160.240106] task: f4518000 task.stack: f47b6000
[  160.240106] EIP: ext4_block_zero_page_range+0x1a7/0x2b4
[  160.240106] EFLAGS: 00010246 CPU: 0
[  160.240106] EAX: 00000001 EBX: f7be4b50 ECX: f47b7dc0 EDX: 00000007
[  160.240106] ESI: f43b05a8 EDI: f43babec EBP: f47b7dd0 ESP: f47b7dac
[  160.240106]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[  160.240106] CR0: 80050033 CR2: bfd85b08 CR3: 34a00680 CR4: 000006f0
[  160.240106] Call Trace:
[  160.240106]  ext4_truncate+0x1e9/0x3e5
[  160.240106]  ext4_fill_super+0x286f/0x2b1e
[  160.240106]  ? set_blocksize+0x2e/0x7e
[  160.240106]  mount_bdev+0x114/0x15f
[  160.240106]  ext4_mount+0x15/0x17
[  160.240106]  ? ext4_calculate_overhead+0x39d/0x39d
[  160.240106]  mount_fs+0x58/0x115
[  160.240106]  vfs_kern_mount+0x4b/0xae
[  160.240106]  do_mount+0x671/0x8c3
[  160.240106]  ? _copy_from_user+0x70/0x83
[  160.240106]  ? strndup_user+0x31/0x46
[  160.240106]  SyS_mount+0x57/0x7b
[  160.240106]  do_int80_syscall_32+0x4f/0x61
[  160.240106]  entry_INT80_32+0x2f/0x2f
[  160.240106] EIP: 0xb76b919e
[  160.240106] EFLAGS: 00000246 CPU: 0
[  160.240106] EAX: ffffffda EBX: 08053838 ECX: 08052188 EDX: 080537e8
[  160.240106] ESI: c0ed0000 EDI: 00000000 EBP: 080537e8 ESP: bfa13660
[  160.240106]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
[  160.240106] Code: 59 8b 00 a8 01 0f 84 09 01 00 00 8b 07 66 25 00 f0 66 3d 00 80 75 61 89 f8 e8 3e e2 ff ff 84 c0 74 56 83 bf 48 02 00 00 00 75 02 <0f> 0b 81 7d e8 00 10 00 00 74 02 0f 0b 8b 43 04 8b 53 08 31 c9
[  160.240106] EIP: ext4_block_zero_page_range+0x1a7/0x2b4 SS:ESP: 0068:f47b7dac
[  160.317241] ---[ end trace d6a773a375c810a5 ]---

The problem is that when the kernel tries to truncate an inode in
ext4_truncate(), it tries to clear any on-disk data beyond i_size.
Without the encryption key, it can't do that, and so it triggers a
BUG.

E2fsck does *not* provide this service, and in practice most file
systems have their orphan list processed by e2fsck, so to avoid
crashing, this patch skips this step if we don't have access to the
encryption key (which is the case when processing the orphan list; in
all other cases, we will have the encryption key, or the kernel
wouldn't have allowed the file to be opened).

An open question is whether the fact that e2fsck isn't clearing the
bytes beyond i_size causing problems --- and if we've lived with it
not doing it for so long, can we drop this from the kernel replay of
the orphan list in all cases (not just when we don't have the key for
encrypted inodes).

Addresses-Google-Bug: #35209576

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>