Bug 2347705 (CVE-2022-49256)

Summary: CVE-2022-49256 kernel: watch_queue: Actually free the watch
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-02-26 03:03:51 UTC
In the Linux kernel, the following vulnerability has been resolved:

watch_queue: Actually free the watch

free_watch() does everything barring actually freeing the watch object.  Fix
this by adding the missing kfree.

kmemleak produces a report something like the following.  Note that as an
address can be seen in the first word, the watch would appear to have gone
through call_rcu().

BUG: memory leak
unreferenced object 0xffff88810ce4a200 (size 96):
  comm "syz-executor352", pid 3605, jiffies 4294947473 (age 13.720s)
  hex dump (first 32 bytes):
    e0 82 48 0d 81 88 ff ff 00 00 00 00 00 00 00 00  ..H.............
    80 a2 e4 0c 81 88 ff ff 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8214e6cc>] kmalloc include/linux/slab.h:581 [inline]
    [<ffffffff8214e6cc>] kzalloc include/linux/slab.h:714 [inline]
    [<ffffffff8214e6cc>] keyctl_watch_key+0xec/0x2e0 security/keys/keyctl.c:1800
    [<ffffffff8214ec84>] __do_sys_keyctl+0x3c4/0x490 security/keys/keyctl.c:2016
    [<ffffffff84493a25>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff84493a25>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84600068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Comment 1 Avinash Hanwate 2025-02-26 14:05:19 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022627-CVE-2022-49256-042d@gregkh/T

Comment 4 Avinash Hanwate 2025-02-26 18:11:31 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022627-CVE-2022-49256-042d@gregkh/T