CVE-2023-53136

/// Technical description

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

af_unix: fix struct pid leaks in OOB support

syzbot reported struct pid leak [1].

Issue is that queue_oob() calls maybe_add_creds() which potentially

holds a reference on a pid.

But skb->destructor is not set (either directly or by calling

unix_scm_to_skb())

This means that subsequent kfree_skb() or consume_skb() would leak

this reference.

In this fix, I chose to fully support scm even for the OOB message.

[1]

BUG: memory leak

unreferenced object 0xffff8881053e7f80 (size 128):

comm "syz-executor242", pid 5066, jiffies 4294946079 (age 13.220s)

hex dump (first 32 bytes):

01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................

backtrace:

[<ffffffff812ae26a>] alloc_pid+0x6a/0x560 kernel/pid.c:180

[<ffffffff812718df>] copy_process+0x169f/0x26c0 kernel/fork.c:2285

[<ffffffff81272b37>] kernel_clone+0xf7/0x610 kernel/fork.c:2684

[<ffffffff812730cc

/// 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