linux-cve-announce - CVE-2022-50782: ext4: fix bug_on in __es_tree

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Message-ID: <2025122402-CVE-2022-50782-d849@gregkh>
Date: Wed, 24 Dec 2025 14:06:33 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50782: ext4: fix bug_on in __es_tree_search caused by bad quota inode

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix bug_on in __es_tree_search caused by bad quota inode

We got a issue as fllows:
==================================================================
 kernel BUG at fs/ext4/extents_status.c:202!
 invalid opcode: 0000 [#1] PREEMPT SMP
 CPU: 1 PID: 810 Comm: mount Not tainted 6.1.0-rc1-next-g9631525255e3 #352
 RIP: 0010:__es_tree_search.isra.0+0xb8/0xe0
 RSP: 0018:ffffc90001227900 EFLAGS: 00010202
 RAX: 0000000000000000 RBX: 0000000077512a0f RCX: 0000000000000000
 RDX: 0000000000000002 RSI: 0000000000002a10 RDI: ffff8881004cd0c8
 RBP: ffff888177512ac8 R08: 47ffffffffffffff R09: 0000000000000001
 R10: 0000000000000001 R11: 00000000000679af R12: 0000000000002a10
 R13: ffff888177512d88 R14: 0000000077512a10 R15: 0000000000000000
 FS: 00007f4bd76dbc40(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00005653bf993cf8 CR3: 000000017bfdf000 CR4: 00000000000006e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  <TASK>
  ext4_es_cache_extent+0xe2/0x210
  ext4_cache_extents+0xd2/0x110
  ext4_find_extent+0x5d5/0x8c0
  ext4_ext_map_blocks+0x9c/0x1d30
  ext4_map_blocks+0x431/0xa50
  ext4_getblk+0x82/0x340
  ext4_bread+0x14/0x110
  ext4_quota_read+0xf0/0x180
  v2_read_header+0x24/0x90
  v2_check_quota_file+0x2f/0xa0
  dquot_load_quota_sb+0x26c/0x760
  dquot_load_quota_inode+0xa5/0x190
  ext4_enable_quotas+0x14c/0x300
  __ext4_fill_super+0x31cc/0x32c0
  ext4_fill_super+0x115/0x2d0
  get_tree_bdev+0x1d2/0x360
  ext4_get_tree+0x19/0x30
  vfs_get_tree+0x26/0xe0
  path_mount+0x81d/0xfc0
  do_mount+0x8d/0xc0
  __x64_sys_mount+0xc0/0x160
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  </TASK>
==================================================================

Above issue may happen as follows:
-------------------------------------
ext4_fill_super
 ext4_orphan_cleanup
  ext4_enable_quotas
   ext4_quota_enable
    ext4_iget --> get error inode <5>
     ext4_ext_check_inode --> Wrong imode makes it escape inspection
     make_bad_inode(inode) --> EXT4_BOOT_LOADER_INO set imode
    dquot_load_quota_inode
     vfs_setup_quota_inode --> check pass
     dquot_load_quota_sb
      v2_check_quota_file
       v2_read_header
        ext4_quota_read
         ext4_bread
          ext4_getblk
           ext4_map_blocks
            ext4_ext_map_blocks
             ext4_find_extent
              ext4_cache_extents
               ext4_es_cache_extent
                __es_tree_search.isra.0
                 ext4_es_end --> Wrong extents trigger BUG_ON

In the above issue, s_usr_quota_inum is set to 5, but inode<5> contains
incorrect imode and disordered extents. Because 5 is EXT4_BOOT_LOADER_INO,
the ext4_ext_check_inode check in the ext4_iget function can be bypassed,
finally, the extents that are not checked trigger the BUG_ON in the
__es_tree_search function. To solve this issue, check whether the inode is
bad_inode in vfs_setup_quota_inode().

The Linux kernel CVE team has assigned CVE-2022-50782 to this issue.


Affected and fixed versions
===========================

	Fixed in 4.19.270 with commit fb1d3b4107b4837b4a0dbbf01954269bd6acfdc3
	Fixed in 5.4.229 with commit 1d5524832ff204b8a8cd54ae1628b2122f6e9a8d
	Fixed in 5.10.163 with commit 98004f926d27eaccdd2d336b7916a42e07392da1
	Fixed in 5.15.87 with commit 0dcbf4dc3d54aab5990952cfd832042fb300dbe3
	Fixed in 6.0.18 with commit 794c9175db1f2e5d2a28c326f10bd024dbd944f8
	Fixed in 6.1.4 with commit 1daff79463d7d76096c84c57cddc30c5d4be2226
	Fixed in 6.2 with commit d323877484765aaacbb2769b06e355c2041ed115

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-50782
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/quota/dquot.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/fb1d3b4107b4837b4a0dbbf01954269bd6acfdc3
	https://git.kernel.org/stable/c/1d5524832ff204b8a8cd54ae1628b2122f6e9a8d
	https://git.kernel.org/stable/c/98004f926d27eaccdd2d336b7916a42e07392da1
	https://git.kernel.org/stable/c/0dcbf4dc3d54aab5990952cfd832042fb300dbe3
	https://git.kernel.org/stable/c/794c9175db1f2e5d2a28c326f10bd024dbd944f8
	https://git.kernel.org/stable/c/1daff79463d7d76096c84c57cddc30c5d4be2226
	https://git.kernel.org/stable/c/d323877484765aaacbb2769b06e355c2041ed115