cve/published/2024/CVE-2024-56701.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-2024-56701: powerpc/pseries: Fix dtl_access_lock to be a rw_semaphore

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

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

powerpc/pseries: Fix dtl_access_lock to be a rw_semaphore

The dtl_access_lock needs to be a rw_sempahore, a sleeping lock, because
the code calls kmalloc() while holding it, which can sleep:

  # echo 1 > /proc/powerpc/vcpudispatch_stats
  BUG: sleeping function called from invalid context at include/linux/sched/mm.h:337
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 199, name: sh
  preempt_count: 1, expected: 0
  3 locks held by sh/199:
   #0: c00000000a0743f8 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x324/0x438
   #1: c0000000028c7058 (dtl_enable_mutex){+.+.}-{3:3}, at: vcpudispatch_stats_write+0xd4/0x5f4
   #2: c0000000028c70b8 (dtl_access_lock){+.+.}-{2:2}, at: vcpudispatch_stats_write+0x220/0x5f4
  CPU: 0 PID: 199 Comm: sh Not tainted 6.10.0-rc4 #152
  Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries
  Call Trace:
    dump_stack_lvl+0x130/0x148 (unreliable)
    __might_resched+0x174/0x410
    kmem_cache_alloc_noprof+0x340/0x3d0
    alloc_dtl_buffers+0x124/0x1ac
    vcpudispatch_stats_write+0x2a8/0x5f4
    proc_reg_write+0xf4/0x150
    vfs_write+0xfc/0x438
    ksys_write+0x88/0x148
    system_call_exception+0x1c4/0x5a0
    system_call_common+0xf4/0x258

The Linux kernel CVE team has assigned CVE-2024-56701 to this issue.


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

	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 5.10.231 with commit 6956c0e7346ce1bbfc726755aa8da10d26e84276
	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 5.15.174 with commit f6ec133668757f84e5143f1eb141fd0b83778b9e
	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 6.1.120 with commit fa5b5ea257135e771b489c83a2e93b5935d0108e
	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 6.6.64 with commit a246daa26b717e755ccc9061f47f7cd1c0b358dd
	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 6.11.11 with commit b125d0cf1adde7b2b47d7337fed7e9133eea3463
	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 6.12.2 with commit 525e18f1ba7c2b098c8ba587fb397efb34a6574c
	Issue introduced in 5.3 with commit 06220d78f24a20549757be1014e57c382406cc92 and fixed in 6.13 with commit cadae3a45d23aa4f6485938a67cbc47aaaa25e38

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-2024-56701
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:
	arch/powerpc/include/asm/dtl.h
	arch/powerpc/platforms/pseries/dtl.c
	arch/powerpc/platforms/pseries/lpar.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/6956c0e7346ce1bbfc726755aa8da10d26e84276
	https://git.kernel.org/stable/c/f6ec133668757f84e5143f1eb141fd0b83778b9e
	https://git.kernel.org/stable/c/fa5b5ea257135e771b489c83a2e93b5935d0108e
	https://git.kernel.org/stable/c/a246daa26b717e755ccc9061f47f7cd1c0b358dd
	https://git.kernel.org/stable/c/b125d0cf1adde7b2b47d7337fed7e9133eea3463
	https://git.kernel.org/stable/c/525e18f1ba7c2b098c8ba587fb397efb34a6574c
	https://git.kernel.org/stable/c/cadae3a45d23aa4f6485938a67cbc47aaaa25e38