Bug 2363420 (CVE-2022-49842)

Summary: CVE-2022-49842 kernel: ASoC: core: Fix use-after-free in snd_soc_exit()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-05-01 15:03:57 UTC
In the Linux kernel, the following vulnerability has been resolved:

ASoC: core: Fix use-after-free in snd_soc_exit()

KASAN reports a use-after-free:

BUG: KASAN: use-after-free in device_del+0xb5b/0xc60
Read of size 8 at addr ffff888008655050 by task rmmod/387
CPU: 2 PID: 387 Comm: rmmod
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
<TASK>
dump_stack_lvl+0x79/0x9a
print_report+0x17f/0x47b
kasan_report+0xbb/0xf0
device_del+0xb5b/0xc60
platform_device_del.part.0+0x24/0x200
platform_device_unregister+0x2e/0x40
snd_soc_exit+0xa/0x22 [snd_soc_core]
__do_sys_delete_module.constprop.0+0x34f/0x5b0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
...
</TASK>

It's bacause in snd_soc_init(), snd_soc_util_init() is possble to fail,
but its ret is ignored, which makes soc_dummy_dev unregistered twice.

snd_soc_init()
    snd_soc_util_init()
        platform_device_register_simple(soc_dummy_dev)
        platform_driver_register() # fail
    	platform_device_unregister(soc_dummy_dev)
    platform_driver_register() # success
...
snd_soc_exit()
    snd_soc_util_exit()
    # soc_dummy_dev will be unregistered for second time

To fix it, handle error and stop snd_soc_init() when util_init() fail.
Also clean debugfs when util_init() or driver_register() fail.

Comment 1 Avinash Hanwate 2025-05-02 04:32:23 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050140-CVE-2022-49842-54c5@gregkh/T