Subject: CVE-2024-42082: xdp: Remove WARN() from __xdp_reg_mem_model()

From: Greg Kroah-Hartman <[email-masked]>

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

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

xdp: Remove WARN() from __xdp_reg_mem_model()

syzkaller reports a warning in __xdp_reg_mem_model().

The warning occurs only if __mem_id_init_hash_table() returns an error. It
returns the error in two cases:

  1. memory allocation fails;
  2. rhashtable_init() fails when some fields of rhashtable_params
     struct are not initialized properly.

The second case cannot happen since there is a static const rhashtable_params
struct with valid fields. So, warning is only triggered when there is a
problem with memory allocation.

Thus, there is no sense in using WARN() to handle this error and it can be
safely removed.

WARNING: CPU: 0 PID: 5065 at net/core/xdp.c:299 __xdp_reg_mem_model+0x2d9/0x650 net/core/xdp.c:299

CPU: 0 PID: 5065 Comm: syz-executor883 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__xdp_reg_mem_model+0x2d9/0x650 net/core/xdp.c:299

Call Trace:
 xdp_reg_mem_model+0x22/0x40 net/core/xdp.c:344
 xdp_test_run_setup net/bpf/test_run.c:188 [inline]
 bpf_test_run_xdp_live+0x365/0x1e90 net/bpf/test_run.c:377
 bpf_prog_test_run_xdp+0x813/0x11b0 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x33a/0x3b0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Found by Linux Verification Center (linuxtesting.org) with syzkaller.

The Linux kernel CVE team has assigned CVE-2024-42082 to this issue.

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

	Issue introduced in 4.18 with commit 8d5d88527587 and fixed in 5.10.221 with commit 1095b8efbb13
	Issue introduced in 4.18 with commit 8d5d88527587 and fixed in 5.15.162 with commit 1d3e3b3aa2cb
	Issue introduced in 4.18 with commit 8d5d88527587 and fixed in 6.1.97 with commit 4e0c539ee265
	Issue introduced in 4.18 with commit 8d5d88527587 and fixed in 6.6.37 with commit 14e51ea78b4c
	Issue introduced in 4.18 with commit 8d5d88527587 and fixed in 6.9.8 with commit f92298b0467f
	Issue introduced in 4.18 with commit 8d5d88527587 and fixed in 6.10 with commit 7e9f79428372

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-2024-42082
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/xdp.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/1095b8efbb13a6a5fa583ed373ee1ccab29da2d0
	https://git.kernel.org/stable/c/1d3e3b3aa2cbe9bc7db9a7f8673a9fa6d2990d54
	https://git.kernel.org/stable/c/4e0c539ee265d5c6e7fa7d229cd4aa7bc01816e2
	https://git.kernel.org/stable/c/14e51ea78b4ccacb7acb1346b9241bb790a2054c
	https://git.kernel.org/stable/c/f92298b0467fd77edc4c1a2c3e48833e69840ec4
	https://git.kernel.org/stable/c/7e9f79428372c6eab92271390851be34ab26bfb4