CVE-2022-49900: i2c: piix4: Fix adapter not be removed in piix4_remove()
In the Linux kernel, the following vulnerability has been resolved:
i2c: piix4: Fix adapter not be removed in piix4remove()
In piix4probe(), the piix4 adapter will be registered in:
piix4probe() piix4addadapterssb800() / piix4addadapter() i2caddadapter()
Based on the probed device type, piix4addadapterssb800() or single piix4addadapter() will be called. For the former case, piix4adaptercount is set as the number of adapters, while for antoher case it is not set and kept default zero.
When piix4 is removed, piix4remove() removes the adapters added in piix4probe(), basing on the piix4adaptercount value. Because the count is zero for the single adapter case, the adapter won't be removed and makes the sources allocated for adapter leaked, such as the i2c client and device.
These sources can still be accessed by i2c or bus and cause problems. An easily reproduced case is that if a new adapter is registered, i2c will get the leaked adapter and try to call smbusalgorithm, which was already freed:
Triggered by: rmmod i2cpiix4 && modprobe max31730
BUG: unable to handle page fault for address: ffffffffc053d860 #PF: supervisor read access in kernel mode #PF: errorcode(0x0000) - not-present page Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3752 Comm: modprobe Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:i2cdefaultprobe (drivers/i2c/i2c-core-base.c:2259) i2ccore RSP: 0018:ffff888107477710 EFLAGS: 00000246 ... <TASK> i2cdetect (drivers/i2c/i2c-core-base.c:2302) i2ccore processnewdriver (drivers/i2c/i2c-core-base.c:1336) i2ccore busforeachdev (drivers/base/bus.c:301) i2cforeachdev (drivers/i2c/i2c-core-base.c:1823) i2ccore i2cregisterdriver (drivers/i2c/i2c-core-base.c:1861) i2ccore dooneinitcall (init/main.c:1296) doinitmodule (kernel/module/main.c:2455) ... </TASK> ---[ end trace 0000000000000000 ]---
Fix this problem by correctly set piix4adaptercount as 1 for the single adapter so it can be normally removed.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.0.8-1 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 5.10.154 - Upgrade
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linux/Kernelto a version that resolves this vulnerability.Fixed in 6.0.8 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.15-1 - Configuration
Set piix4_adapter_count to 1 for the single-adapter case so the adapter is removed normally in piix4_remove().
Linux kernel i2c piix4 driver piix4_adapter_count = 1
Event History
Frequently Asked Questions
What is the severity of CVE-2022-49900?
CVE-2022-49900 has been classified as a low severity vulnerability in the Linux kernel.
How do I fix CVE-2022-49900?
To fix CVE-2022-49900, update your Linux kernel to the latest version that includes the patch.
What is affected by CVE-2022-49900?
CVE-2022-49900 affects the Linux kernel specifically related to the piix4 adapter handling.
Is CVE-2022-49900 exploitable?
CVE-2022-49900 does not appear to have a known exploit or immediate risk for users.
When was CVE-2022-49900 published?
CVE-2022-49900 was published on December 8, 2022.