CVE-2022-49990
In the Linux kernel, the following vulnerability has been resolved: s390: fix double free of GS and RI CBs on fork() failure The pointers for guarded storage and runtime instrumentation control blocks are stored in the thread_struct of the associated…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: s390: fix double free of GS and RI CBs on fork() failure The pointers for guarded storage and runtime instrumentation control blocks are stored in the thread_struct of the associated task. These pointers are initially copied on fork() via arch_dup_task_struct() and then cleared via copy_thread() before fork() returns. If fork() happens to fail after the initial task dup and before copy_thread(), the newly allocated task and associated thread_struct memory are freed via free_task() -> arch_release_task_struct(). This results in a double free of the guarded storage and runtime info structs because the fields in the failed task still refer to memory associated with the source task. This problem can manifest as a BUG_ON() in set_freepointer() (with CONFIG_SLAB_FREELIST_HARDENED enabled) or KASAN splat (if enabled) when running trinity syscall fuzz tests on s390x. To avoid this problem, clear the associated pointer fields in arch_dup_task_struct() immediately after the new task is copied. Note that the RI flag is still cleared in copy_thread() because it resides in thread stack memory and that is where stack info is copied.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.24% probability · 16th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-415
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/13cccafe0edcd03bf1c841de8ab8a1c8e34f77d9Patch
- https://git.kernel.org/stable/c/25a95303b9e513cd2978aacc385d06e6fec23d07Patch
- https://git.kernel.org/stable/c/297ae7e87a87a001dd3dfeac1cb26a42fd929708Patch
- https://git.kernel.org/stable/c/8195e065abf3df84eb0ad2987e76a40f21d1791cPatch
- https://git.kernel.org/stable/c/cacd522e6652fbc2dc0cc6ae11c4e30782fef14bPatch
- https://git.kernel.org/stable/c/fbdc482d43eda40a70de4b0155843d5472f6de62Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.