CVE-2023-53479

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

cxl/acpi: Fix a use-after-free in cxl_parse_cfmws()

KASAN and KFENCE detected an user-after-free in the CXL driver. This happens in the cxl_decoder_add() fail path. KASAN prints the following error:

BUG: KASAN: slab-use-after-free in cxl_parse_cfmws (drivers/cxl/acpi.c:299)

This happens in cxl_parse_cfmws(), where put_device() is called, releasing cxld, which is accessed later.

Use the local variables in the dev_err() instead of pointing to the released memory. Since the dev_err() is printing a resource, change the open coded print format to use the %pr format specifier.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/316db489647b8ddc381682597e89787eac61a278
• https://git.kernel.org/stable/c/4cf67d3cc9994a59cf77bb9c0ccf9007fe916afe
• https://git.kernel.org/stable/c/748fadc08bcbdaf573b34d9784bb3dbd87441dbf