linux-stable.git/fs/ext4, branch linux-4.1.y Linux kernel stable tree ext4: bugfix for mmaped pages in mpage_release_unused_pages() 2018-05-23T01:36:35+00:00 wangguang wang.guang55@zte.com.cn 2016-09-15T15:32:46+00:00 697acc5a549c082e2fa6f053a3d3dc9831d4f943 [ Upstream commit 4e800c0359d9a53e6bf0ab216954971b2515247f ] Pages clear buffers after ext4 delayed block allocation failed, However, it does not clean its pte_dirty flag. if the pages unmap ,in cording to the pte_dirty , unmap_page_range may try to call __set_page_dirty, which may lead to the bugon at mpage_prepare_extent_to_map:head = page_buffers(page);. This patch just call clear_page_dirty_for_io to clean pte_dirty at mpage_release_unused_pages for pages mmaped. Steps to reproduce the bug: （1） mmap a file in ext4 addr = (char *)mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); memset(addr, 'i', 4096); （2） return EIO at ext4_writepages->mpage_map_and_submit_extent->mpage_map_one_extent which causes this log message to be print: ext4_msg(sb, KERN_CRIT, "Delayed block allocation failed for " "inode %lu at logical offset %llu with" " max blocks %u with error %d", inode->i_ino, (unsigned long long)map->m_lblk, (unsigned)map->m_len, -err); (3）Unmap the addr cause warning at __set_page_dirty:WARN_ON_ONCE(warn && !PageUptodate(page)); (4) wait for a minute,then bugon happen. Cc: stable@vger.kernel.org Signed-off-by: wangguang <wangguang03@zte.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit 4e800c0359d9a53e6bf0ab216954971b2515247f ]

Pages clear buffers after ext4 delayed block allocation failed,
However, it does not clean its pte_dirty flag.
if the pages unmap ,in cording to the pte_dirty ,
unmap_page_range may try to call __set_page_dirty,

which may lead to the bugon at
mpage_prepare_extent_to_map:head = page_buffers(page);.

This patch just call clear_page_dirty_for_io to clean pte_dirty
at mpage_release_unused_pages for pages mmaped.

Steps to reproduce the bug:

（1） mmap a file in ext4
	addr = (char *)mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED,
	       	            fd, 0);
	memset(addr, 'i', 4096);

（2） return EIO at

	ext4_writepages->mpage_map_and_submit_extent->mpage_map_one_extent

which causes this log message to be print:

                ext4_msg(sb, KERN_CRIT,
                        "Delayed block allocation failed for "
                        "inode %lu at logical offset %llu with"
                        " max blocks %u with error %d",
                        inode->i_ino,
                        (unsigned long long)map->m_lblk,
                        (unsigned)map->m_len, -err);

(3）Unmap the addr cause warning at

	__set_page_dirty:WARN_ON_ONCE(warn && !PageUptodate(page));

(4) wait for a minute,then bugon happen.

Cc: stable@vger.kernel.org
Signed-off-by: wangguang <wangguang03@zte.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4: don't allow r/w mounts if metadata blocks overlap the superblock 2018-05-23T01:36:34+00:00 Theodore Ts'o tytso@mit.edu 2018-03-30T02:10:35+00:00 176df3e2add7cd7029a3493ea825e5582cb84ef0 [ Upstream commit 18db4b4e6fc31eda838dd1c1296d67dbcb3dc957 ] If some metadata block, such as an allocation bitmap, overlaps the superblock, it's very likely that if the file system is mounted read/write, the results will not be pretty. So disallow r/w mounts for file systems corrupted in this particular way. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit 18db4b4e6fc31eda838dd1c1296d67dbcb3dc957 ]

If some metadata block, such as an allocation bitmap, overlaps the
superblock, it's very likely that if the file system is mounted
read/write, the results will not be pretty.  So disallow r/w mounts
for file systems corrupted in this particular way.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4: fix off-by-one on max nr_pages in ext4_find_unwritten_pgoff() 2018-05-23T01:36:25+00:00 Eryu Guan eguan@redhat.com 2017-05-24T22:02:20+00:00 6fc9ae9d8740e0ed35648a7a37c875b811ad0553 [ Upstream commit 624327f8794704c5066b11a52f9da6a09dce7f9a ] ext4_find_unwritten_pgoff() is used to search for offset of hole or data in page range [index, end] (both inclusive), and the max number of pages to search should be at least one, if end == index. Otherwise the only page is missed and no hole or data is found, which is not correct. When block size is smaller than page size, this can be demonstrated by preallocating a file with size smaller than page size and writing data to the last block. E.g. run this xfs_io command on a 1k block size ext4 on x86_64 host. # xfs_io -fc "falloc 0 3k" -c "pwrite 2k 1k" \ -c "seek -d 0" /mnt/ext4/testfile wrote 1024/1024 bytes at offset 2048 1 KiB, 1 ops; 0.0000 sec (42.459 MiB/sec and 43478.2609 ops/sec) Whence Result DATA EOF Data at offset 2k was missed, and lseek(2) returned ENXIO. This is unconvered by generic/285 subtest 07 and 08 on ppc64 host, where pagesize is 64k. Because a recent change to generic/285 reduced the preallocated file size to smaller than 64k. Signed-off-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit 624327f8794704c5066b11a52f9da6a09dce7f9a ]

ext4_find_unwritten_pgoff() is used to search for offset of hole or
data in page range [index, end] (both inclusive), and the max number
of pages to search should be at least one, if end == index.
Otherwise the only page is missed and no hole or data is found,
which is not correct.

When block size is smaller than page size, this can be demonstrated
by preallocating a file with size smaller than page size and writing
data to the last block. E.g. run this xfs_io command on a 1k block
size ext4 on x86_64 host.

  # xfs_io -fc "falloc 0 3k" -c "pwrite 2k 1k" \
  	    -c "seek -d 0" /mnt/ext4/testfile
  wrote 1024/1024 bytes at offset 2048
  1 KiB, 1 ops; 0.0000 sec (42.459 MiB/sec and 43478.2609 ops/sec)
  Whence  Result
  DATA    EOF

Data at offset 2k was missed, and lseek(2) returned ENXIO.

This is unconvered by generic/285 subtest 07 and 08 on ppc64 host,
where pagesize is 64k. Because a recent change to generic/285
reduced the preallocated file size to smaller than 64k.

Signed-off-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4 crypto: don't regenerate the per-inode encryption key unnecessarily 2018-03-04T15:28:35+00:00 Theodore Ts'o tytso@mit.edu 2018-03-02T22:21:13+00:00 9e6aba7422fd988b3345d51f96503cf3b148db6f [ Relevant upstream commit: 1b53cf9815bb4744958d41f3795d5d5a1d365e2d ] This fixes the same problem as upstream commit 1b53cf9815bb: "fscrypt: remove broken support for detecting keyring key revocation". Specifically, key revocations racing with readpage operations will cause the kernel to crash and burn with a BUG_ON or a NULL pointer dereference in a block I/O callback stemming from an ext4_readpage() operation. This fix is needed to fix prevent xfstests test runs from crashing while running the generic/421 test. The root cause is different in the 4.1 kernel, however, since the 4.1's encryption handling is so _primitive_ compared to later kernels. The code isn't actually explicitly checking for revoked keys. Instead, the code is neededly regenerating the per-file encryption key on every mmap() or open() or directory operation (in the case of a directory inode). Yelch! If the file is already opened and actively being read, and while an open() is racing with the read operations, after the user's master key has been revoked, there will be the same net effect as the problem fixed by upstream commit 1b53cf9815bb --- the per-file key will be marked as invalid and this will cause a BUG_ON. The AOSP 3.18 and 4.4 android-common kernels have a much more modern version of ext4 encryption have been backported, which incldes a backport of upstream commit 1b53cf9815bb. This is a (at least) dozen-plus commits, and isn't really suitable for the Upstream LTS kernel. So instead, this is the simplest bug which fixes the same high-level issue as the upstream commit, without dragging in all of the other non-bug-fix improvements to ext4 encryption found in newer kernels. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Relevant upstream commit: 1b53cf9815bb4744958d41f3795d5d5a1d365e2d ]

This fixes the same problem as upstream commit 1b53cf9815bb: "fscrypt:
remove broken support for detecting keyring key revocation".
Specifically, key revocations racing with readpage operations will
cause the kernel to crash and burn with a BUG_ON or a NULL pointer
dereference in a block I/O callback stemming from an ext4_readpage()
operation.

This fix is needed to fix prevent xfstests test runs from crashing
while running the generic/421 test.

The root cause is different in the 4.1 kernel, however, since the
4.1's encryption handling is so _primitive_ compared to later kernels.
The code isn't actually explicitly checking for revoked keys.
Instead, the code is neededly regenerating the per-file encryption key
on every mmap() or open() or directory operation (in the case of a
directory inode).  Yelch!

If the file is already opened and actively being read, and while an
open() is racing with the read operations, after the user's master key
has been revoked, there will be the same net effect as the problem
fixed by upstream commit 1b53cf9815bb --- the per-file key will be
marked as invalid and this will cause a BUG_ON.

The AOSP 3.18 and 4.4 android-common kernels have a much more modern
version of ext4 encryption have been backported, which incldes a
backport of upstream commit 1b53cf9815bb.  This is a (at least)
dozen-plus commits, and isn't really suitable for the Upstream LTS
kernel.  So instead, this is the simplest bug which fixes the same
high-level issue as the upstream commit, without dragging in all of
the other non-bug-fix improvements to ext4 encryption found in newer
kernels.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
fscrypto: add authorization check for setting encryption policy 2018-03-04T15:28:35+00:00 Eric Biggers ebiggers@google.com 2018-03-02T22:21:12+00:00 e68557814c7e9e4943caca924ff5537952bb3b4e commit 163ae1c6ad6299b19e22b4a35d5ab24a89791a98 upstream. On an ext4 or f2fs filesystem with file encryption supported, a user could set an encryption policy on any empty directory(*) to which they had readonly access. This is obviously problematic, since such a directory might be owned by another user and the new encryption policy would prevent that other user from creating files in their own directory (for example). Fix this by requiring inode_owner_or_capable() permission to set an encryption policy. This means that either the caller must own the file, or the caller must have the capability CAP_FOWNER. (*) Or also on any regular file, for f2fs v4.6 and later and ext4 v4.8-rc1 and later; a separate bug fix is coming for that. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
commit 163ae1c6ad6299b19e22b4a35d5ab24a89791a98 upstream.

On an ext4 or f2fs filesystem with file encryption supported, a user
could set an encryption policy on any empty directory(*) to which they
had readonly access.  This is obviously problematic, since such a
directory might be owned by another user and the new encryption policy
would prevent that other user from creating files in their own directory
(for example).

Fix this by requiring inode_owner_or_capable() permission to set an
encryption policy.  This means that either the caller must own the file,
or the caller must have the capability CAP_FOWNER.

(*) Or also on any regular file, for f2fs v4.6 and later and ext4
    v4.8-rc1 and later; a separate bug fix is coming for that.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4: require encryption feature for EXT4_IOC_SET_ENCRYPTION_POLICY 2018-03-04T15:28:35+00:00 Richard Weinberger richard@nod.at 2018-03-02T22:21:11+00:00 ed6923107e5d09dfe1e79bf8f3cdb6815994d216 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: Sasha Levin <alexander.levin@microsoft.com> 
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: Sasha Levin <alexander.levin@microsoft.com>
ext4: save error to disk in __ext4_grp_locked_error() 2018-03-04T15:28:23+00:00 Zhouyi Zhou zhouzhouyi@gmail.com 2018-01-10T05:34:19+00:00 ac9822f189aed6520cbc8949e3a7e151abb3bc4d [ Upstream commit 06f29cc81f0350261f59643a505010531130eea0 ] In the function __ext4_grp_locked_error(), __save_error_info() is called to save error info in super block block, but does not sync that information to disk to info the subsequence fsck after reboot. This patch writes the error information to disk. After this patch, I think there is no obvious EXT4 error handle branches which leads to "Remounting filesystem read-only" will leave the disk partition miss the subsequence fsck. Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit 06f29cc81f0350261f59643a505010531130eea0 ]

In the function __ext4_grp_locked_error(), __save_error_info()
is called to save error info in super block block, but does not sync
that information to disk to info the subsequence fsck after reboot.

This patch writes the error information to disk.  After this patch,
I think there is no obvious EXT4 error handle branches which leads to
"Remounting filesystem read-only" will leave the disk partition miss
the subsequence fsck.

Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4: fix crash when a directory's i_size is too small 2018-01-17T17:55:32+00:00 Chandan Rajendra chandan@linux.vnet.ibm.com 2017-12-11T20:00:57+00:00 27bc8f4750a7e61fdbeaf654e6194cada59df75b [ Upstream commit 9d5afec6b8bd46d6ed821aa1579634437f58ef1f ] On a ppc64 machine, when mounting a fuzzed ext2 image (generated by fsfuzzer) the following call trace is seen, VFS: brelse: Trying to free free buffer WARNING: CPU: 1 PID: 6913 at /root/repos/linux/fs/buffer.c:1165 .__brelse.part.6+0x24/0x40 .__brelse.part.6+0x20/0x40 (unreliable) .ext4_find_entry+0x384/0x4f0 .ext4_lookup+0x84/0x250 .lookup_slow+0xdc/0x230 .walk_component+0x268/0x400 .path_lookupat+0xec/0x2d0 .filename_lookup+0x9c/0x1d0 .vfs_statx+0x98/0x140 .SyS_newfstatat+0x48/0x80 system_call+0x58/0x6c This happens because the directory that ext4_find_entry() looks up has inode->i_size that is less than the block size of the filesystem. This causes 'nblocks' to have a value of zero. ext4_bread_batch() ends up not reading any of the directory file's blocks. This renders the entries in bh_use[] array to continue to have garbage data. buffer_uptodate() on bh_use[0] can then return a zero value upon which brelse() function is invoked. This commit fixes the bug by returning -ENOENT when the directory file has no associated blocks. Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit 9d5afec6b8bd46d6ed821aa1579634437f58ef1f ]

On a ppc64 machine, when mounting a fuzzed ext2 image (generated by
fsfuzzer) the following call trace is seen,

VFS: brelse: Trying to free free buffer
WARNING: CPU: 1 PID: 6913 at /root/repos/linux/fs/buffer.c:1165 .__brelse.part.6+0x24/0x40
.__brelse.part.6+0x20/0x40 (unreliable)
.ext4_find_entry+0x384/0x4f0
.ext4_lookup+0x84/0x250
.lookup_slow+0xdc/0x230
.walk_component+0x268/0x400
.path_lookupat+0xec/0x2d0
.filename_lookup+0x9c/0x1d0
.vfs_statx+0x98/0x140
.SyS_newfstatat+0x48/0x80
system_call+0x58/0x6c

This happens because the directory that ext4_find_entry() looks up has
inode->i_size that is less than the block size of the filesystem. This
causes 'nblocks' to have a value of zero. ext4_bread_batch() ends up not
reading any of the directory file's blocks. This renders the entries in
bh_use[] array to continue to have garbage data. buffer_uptodate() on
bh_use[0] can then return a zero value upon which brelse() function is
invoked.

This commit fixes the bug by returning -ENOENT when the directory file
has no associated blocks.

Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4: fix fdatasync(2) after fallocate(2) operation 2018-01-17T17:55:31+00:00 Eryu Guan eguan@redhat.com 2017-12-04T03:52:51+00:00 47711554c6da1a8904abb2ba43d2f7ee1b1b5a00 [ Upstream commit c894aa97577e47d3066b27b32499ecf899bfa8b0 ] Currently, fallocate(2) with KEEP_SIZE followed by a fdatasync(2) then crash, we'll see wrong allocated block number (stat -c %b), the blocks allocated beyond EOF are all lost. fstests generic/468 exposes this bug. Commit 67a7d5f561f4 ("ext4: fix fdatasync(2) after extent manipulation operations") fixed all the other extent manipulation operation paths such as hole punch, zero range, collapse range etc., but forgot the fallocate case. So similarly, fix it by recording the correct journal tid in ext4 inode in fallocate(2) path, so that ext4_sync_file() will wait for the right tid to be committed on fdatasync(2). This addresses the test failure in xfstests test generic/468. Signed-off-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit c894aa97577e47d3066b27b32499ecf899bfa8b0 ]

Currently, fallocate(2) with KEEP_SIZE followed by a fdatasync(2)
then crash, we'll see wrong allocated block number (stat -c %b), the
blocks allocated beyond EOF are all lost. fstests generic/468
exposes this bug.

Commit 67a7d5f561f4 ("ext4: fix fdatasync(2) after extent
manipulation operations") fixed all the other extent manipulation
operation paths such as hole punch, zero range, collapse range etc.,
but forgot the fallocate case.

So similarly, fix it by recording the correct journal tid in ext4
inode in fallocate(2) path, so that ext4_sync_file() will wait for
the right tid to be committed on fdatasync(2).

This addresses the test failure in xfstests test generic/468.

Signed-off-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
ext4: don't BUG when truncating encrypted inodes on the orphan list 2018-01-17T17:27:24+00:00 Theodore Ts'o tytso@mit.edu 2017-02-14T16:31:15+00:00 3f51d19d98be281113d2eb801c9021621bb75304 [ Upstream commit 0d06863f903ac5f4f6efb0273079d27de3e53a28 ] 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: Sasha Levin <alexander.levin@microsoft.com> 
[ Upstream commit 0d06863f903ac5f4f6efb0273079d27de3e53a28 ]

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: Sasha Levin <alexander.levin@microsoft.com>