CVE-2022-49256

/// Technical description

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:20

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References