CVE-2022-48649
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: mm/slab_common: fix possible double free of kmem_cache When doing slub_debug test, kfence's 'test_memcache_typesafe_by_rcu' kunit test case cause a use-after-free error: BUG: KASAN: use-after-free in kobject_del+0x14/0x30 Read of size 8 at addr ffff888007679090 by task kunit_try_catch/261 CPU: 1 PID: 261 Comm: kunit_try_catch Tainted: G B N 6.0.0-rc5-next-20220916 #17 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x48 print_address_description.constprop.0+0x87/0x2a5 print_report+0x103/0x1ed kasan_report+0xb7/0x140 kobject_del+0x14/0x30 kmem_cache_destroy+0x130/0x170 test_exit+0x1a/0x30 kunit_try_run_case+0xad/0xc0 kunit_generic_run_threadfn_adapter+0x26/0x50 kthread+0x17b/0x1b0 </TASK> The cause is inside kmem_cache_destroy(): kmem_cache_destroy acquire lock/mutex shutdown_cache schedule_work(kmem_cache_release) (if RCU flag set) release lock/mutex kmem_cache_release (if RCU flag not set) In some certain timing, the scheduled work could be run before the next RCU flag checking, which can then get a wrong value and lead to double kmem_cache_release(). Fix it by caching the RCU flag inside protected area, just like 'refcnt'
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 7.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | High | N/A |
| Integrity Impact | None | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
When a program calls free() twice with the same argument, the program's memory management data structures may become corrupted, potentially leading to the reading or modification of unexpected memory addresses. This corruption can cause the program to crash or, in some circumstances, cause two later calls to malloc() to return the same pointer. If malloc() returns the same value twice and the program later gives the attacker control over the data that is written into this doubly-allocated memory, the program becomes vulnerable to a buffer overflow attack. Doubly freeing memory may result in a write-what-where condition, allowing an attacker to execute arbitrary code.
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