linux-cve-announce - CVE-2023-53485: fs: jfs: Fix UBSAN: array-index-out-of-bounds in dbAllocDmapLev

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Message-ID: <2025100114-CVE-2023-53485-672c@gregkh>
Date: Wed,  1 Oct 2025 13:42:55 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53485: fs: jfs: Fix UBSAN: array-index-out-of-bounds in dbAllocDmapLev

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

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

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

fs: jfs: Fix UBSAN: array-index-out-of-bounds in dbAllocDmapLev

Syzkaller reported the following issue:

UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:1965:6
index -84 is out of range for type 's8[341]' (aka 'signed char[341]')
CPU: 1 PID: 4995 Comm: syz-executor146 Not tainted 6.4.0-rc6-syzkaller-00037-gb6dad5178cea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:217 [inline]
 __ubsan_handle_out_of_bounds+0x11c/0x150 lib/ubsan.c:348
 dbAllocDmapLev+0x3e5/0x430 fs/jfs/jfs_dmap.c:1965
 dbAllocCtl+0x113/0x920 fs/jfs/jfs_dmap.c:1809
 dbAllocAG+0x28f/0x10b0 fs/jfs/jfs_dmap.c:1350
 dbAlloc+0x658/0xca0 fs/jfs/jfs_dmap.c:874
 dtSplitUp fs/jfs/jfs_dtree.c:974 [inline]
 dtInsert+0xda7/0x6b00 fs/jfs/jfs_dtree.c:863
 jfs_create+0x7b6/0xbb0 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3492 [inline]
 open_last_lookups fs/namei.c:3560 [inline]
 path_openat+0x13df/0x3170 fs/namei.c:3788
 do_filp_open+0x234/0x490 fs/namei.c:3818
 do_sys_openat2+0x13f/0x500 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x247/0x290 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f1f4e33f7e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc21129578 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1f4e33f7e9
RDX: 000000000000275a RSI: 0000000020000040 RDI: 00000000ffffff9c
RBP: 00007f1f4e2ff080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1f4e2ff110
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The bug occurs when the dbAllocDmapLev()function attempts to access
dp->tree.stree[leafidx + LEAFIND] while the leafidx value is negative.

To rectify this, the patch introduces a safeguard within the
dbAllocDmapLev() function. A check has been added to verify if leafidx is
negative. If it is, the function immediately returns an I/O error, preventing
any further execution that could potentially cause harm.

Tested via syzbot.

The Linux kernel CVE team has assigned CVE-2023-53485 to this issue.


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

	Fixed in 4.14.324 with commit 0d9e678a82915633b99603f744e7735d1a673d72
	Fixed in 4.19.293 with commit 53b0a362aca2583729e8ca2936ca657ff3247d88
	Fixed in 5.4.255 with commit 6e7d9d76e5654bcdd3cdb7c9441a8113428ecebb
	Fixed in 5.10.192 with commit 911b48eec45152822bccf45cd3563b48256b1520
	Fixed in 5.15.123 with commit 39f6292d75959e8accac0b3e24090094ba0824e9
	Fixed in 6.1.42 with commit bdf07ab1595b613b03f32dbb5cb379edfa1a7334
	Fixed in 6.4.7 with commit f2af019091f904ca08b3572ab0111238ad6d17b3
	Fixed in 6.5 with commit 4e302336d5ca1767a06beee7596a72d3bdc8d983

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-2023-53485
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/jfs/jfs_dmap.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/0d9e678a82915633b99603f744e7735d1a673d72
	https://git.kernel.org/stable/c/53b0a362aca2583729e8ca2936ca657ff3247d88
	https://git.kernel.org/stable/c/6e7d9d76e5654bcdd3cdb7c9441a8113428ecebb
	https://git.kernel.org/stable/c/911b48eec45152822bccf45cd3563b48256b1520
	https://git.kernel.org/stable/c/39f6292d75959e8accac0b3e24090094ba0824e9
	https://git.kernel.org/stable/c/bdf07ab1595b613b03f32dbb5cb379edfa1a7334
	https://git.kernel.org/stable/c/f2af019091f904ca08b3572ab0111238ad6d17b3
	https://git.kernel.org/stable/c/4e302336d5ca1767a06beee7596a72d3bdc8d983