CVE-2023-52994

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

acpi: Fix suspend with Xen PV

Commit f1e525009493 (x86/boot: Skip realmode init code when running as Xen PV guest) missed one code path accessing real_mode_header, leading to dereferencing NULL when suspending the system under Xen:

[  348.284004] PM: suspend entry (deep)
[  348.289532] Filesystems sync: 0.005 seconds
[  348.291545] Freezing user space processes ... (elapsed 0.000 seconds) done.
[  348.292457] OOM killer disabled.
[  348.292462] Freezing remaining freezable tasks ... (elapsed 0.104 seconds) done.
[  348.396612] printk: Suspending console(s) (use no_console_suspend to debug)
[  348.749228] PM: suspend devices took 0.352 seconds
[  348.769713] ACPI: EC: interrupt blocked
[  348.816077] BUG: kernel NULL pointer dereference, address: 000000000000001c
[  348.816080] #PF: supervisor read access in kernel mode
[  348.816081] #PF: error_code(0x0000) - not-present page
[  348.816083] PGD 0 P4D 0
[  348.816086] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  348.816089] CPU: 0 PID: 6764 Comm: systemd-sleep Not tainted 6.1.3-1.fc32.qubes.x86_64 #1
[  348.816092] Hardware name: Star Labs StarBook/StarBook, BIOS 8.01 07/03/2022
[  348.816093] RIP: e030:acpi_get_wakeup_address+0xc/0x20

Fix that by adding an optional acpi callback allowing to skip setting the wakeup address, as in the Xen PV case this will be handled by the hypervisor anyway.

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/b96903b7fc8c82ddfd92df4cdd83db3e567da0a5
• https://git.kernel.org/stable/c/fe0ba8c23f9a35b0307eb662f16dd3a75fcdae41