CVE-2022-49489

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

drm/msm/disp/dpu1: set vbif hw config to NULL to avoid use after memory free during pm runtime resume

BUG: Unable to handle kernel paging request at virtual address 006b6b6b6b6b6be3

Call trace: dpu_vbif_init_memtypes+0x40/0xb8 dpu_runtime_resume+0xcc/0x1c0 pm_generic_runtime_resume+0x30/0x44 __genpd_runtime_resume+0x68/0x7c genpd_runtime_resume+0x134/0x258 __rpm_callback+0x98/0x138 rpm_callback+0x30/0x88 rpm_resume+0x36c/0x49c __pm_runtime_resume+0x80/0xb0 dpu_core_irq_uninstall+0x30/0xb0 dpu_irq_uninstall+0x18/0x24 msm_drm_uninit+0xd8/0x16c

Patchwork: https://patchwork.freedesktop.org/patch/483255/ [DB: fixed Fixes tag]

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References

• https://git.kernel.org/stable/c/134760263f6441741db0b2970e7face6b34b6d1c
• https://git.kernel.org/stable/c/5b0adf5cbf3b74721e4e4c4e0cadc91b8df8bcc2
• https://git.kernel.org/stable/c/97ac682b6f7d36be5d934f86c9911066540a68f1
• https://git.kernel.org/stable/c/aa4cb188988dc6f1b3f4917d4dbc452150a5d871
• https://git.kernel.org/stable/c/ef10d0c68e8608848cd58fca2589685718426607
• https://git.kernel.org/stable/c/ef4bdaac7cb5416f236613ed9337ff0ea8ee329b
• https://git.kernel.org/stable/c/fa5186b279ecf44b14fb435540d2065be91cb1ed