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Message-ID: <2024082105-CVE-2022-48870-3fcb@gregkh>
Date: Wed, 21 Aug 2024 14:11:04 +0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-48870: tty: fix possible null-ptr-defer in spk_ttyio_release
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
tty: fix possible null-ptr-defer in spk_ttyio_release
Run the following tests on the qemu platform:
syzkaller:~# modprobe speakup_audptr
input: Speakup as /devices/virtual/input/input4
initialized device: /dev/synth, node (MAJOR 10, MINOR 125)
speakup 3.1.6: initialized
synth name on entry is: (null)
synth probe
spk_ttyio_initialise_ldisc failed because tty_kopen_exclusive returned
failed (errno -16), then remove the module, we will get a null-ptr-defer
problem, as follow:
syzkaller:~# modprobe -r speakup_audptr
releasing synth audptr
BUG: kernel NULL pointer dereference, address: 0000000000000080
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT SMP PTI
CPU: 2 PID: 204 Comm: modprobe Not tainted 6.1.0-rc6-dirty #1
RIP: 0010:mutex_lock+0x14/0x30
Call Trace:
<TASK>
spk_ttyio_release+0x19/0x70 [speakup]
synth_release.part.6+0xac/0xc0 [speakup]
synth_remove+0x56/0x60 [speakup]
__x64_sys_delete_module+0x156/0x250
? fpregs_assert_state_consistent+0x1d/0x50
do_syscall_64+0x37/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
Modules linked in: speakup_audptr(-) speakup
Dumping ftrace buffer:
in_synth->dev was not initialized during modprobe, so we add check
for in_synth->dev to fix this bug.
The Linux kernel CVE team has assigned CVE-2022-48870 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.12 with commit 4f2a81f3a882 and fixed in 5.15.90 with commit 2da67bff29ab
Issue introduced in 5.12 with commit 4f2a81f3a882 and fixed in 6.1.8 with commit 64152e05a4de
Issue introduced in 5.12 with commit 4f2a81f3a882 and fixed in 6.2 with commit 5abbeebd8296
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-2022-48870
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:
drivers/accessibility/speakup/spk_ttyio.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/2da67bff29ab49caafb0766e8b8383b735ff796f
https://git.kernel.org/stable/c/64152e05a4de3ebf59f1740a0985a6d5fba0c77b
https://git.kernel.org/stable/c/5abbeebd8296c2301023b8dc4b5a6c0d5229b4f5
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