cve/published/2025/CVE-2025-21683.mbox

From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: <linux-cve-announce@vger.kernel.org>
Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: CVE-2025-21683: bpf: Fix bpf_sk_select_reuseport() memory leak

Description
===========

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

bpf: Fix bpf_sk_select_reuseport() memory leak

As pointed out in the original comment, lookup in sockmap can return a TCP
ESTABLISHED socket. Such TCP socket may have had SO_ATTACH_REUSEPORT_EBPF
set before it was ESTABLISHED. In other words, a non-NULL sk_reuseport_cb
does not imply a non-refcounted socket.

Drop sk's reference in both error paths.

unreferenced object 0xffff888101911800 (size 2048):
  comm "test_progs", pid 44109, jiffies 4297131437
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    80 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 9336483b):
    __kmalloc_noprof+0x3bf/0x560
    __reuseport_alloc+0x1d/0x40
    reuseport_alloc+0xca/0x150
    reuseport_attach_prog+0x87/0x140
    sk_reuseport_attach_bpf+0xc8/0x100
    sk_setsockopt+0x1181/0x1990
    do_sock_setsockopt+0x12b/0x160
    __sys_setsockopt+0x7b/0xc0
    __x64_sys_setsockopt+0x1b/0x30
    do_syscall_64+0x93/0x180
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

The Linux kernel CVE team has assigned CVE-2025-21683 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.8 with commit 64d85290d79c0677edb5a8ee2295b36c022fa5df and fixed in 5.10.234 with commit bb36838dac7bb334a3f3d7eb29875593ec9473fc
	Issue introduced in 5.8 with commit 64d85290d79c0677edb5a8ee2295b36c022fa5df and fixed in 5.15.177 with commit 0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf
	Issue introduced in 5.8 with commit 64d85290d79c0677edb5a8ee2295b36c022fa5df and fixed in 6.1.127 with commit d0a3b3d1176d39218b8edb2a2d03164942ab9ccd
	Issue introduced in 5.8 with commit 64d85290d79c0677edb5a8ee2295b36c022fa5df and fixed in 6.6.74 with commit b02e70be498b138e9c21701c2f33f4018ca7cd5e
	Issue introduced in 5.8 with commit 64d85290d79c0677edb5a8ee2295b36c022fa5df and fixed in 6.12.11 with commit cccd51dd22574216e64e5d205489e634f86999f3
	Issue introduced in 5.8 with commit 64d85290d79c0677edb5a8ee2295b36c022fa5df and fixed in 6.13 with commit b3af60928ab9129befa65e6df0310d27300942bf

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-21683
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/core/filter.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/bb36838dac7bb334a3f3d7eb29875593ec9473fc
	https://git.kernel.org/stable/c/0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf
	https://git.kernel.org/stable/c/d0a3b3d1176d39218b8edb2a2d03164942ab9ccd
	https://git.kernel.org/stable/c/b02e70be498b138e9c21701c2f33f4018ca7cd5e
	https://git.kernel.org/stable/c/cccd51dd22574216e64e5d205489e634f86999f3
	https://git.kernel.org/stable/c/b3af60928ab9129befa65e6df0310d27300942bf