Subject: CVE-2024-26681: netdevsim: avoid potential loop in nsim_dev_trap_report_work()

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

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

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

netdevsim: avoid potential loop in nsim_dev_trap_report_work()

Many syzbot reports include the following trace [1]

If nsim_dev_trap_report_work() can not grab the mutex,
it should rearm itself at least one jiffie later.

[1]
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 32383 Comm: kworker/0:2 Not tainted 6.8.0-rc2-syzkaller-00031-g861c0981648f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: events nsim_dev_trap_report_work
 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:89 [inline]
 RIP: 0010:memory_is_nonzero mm/kasan/generic.c:104 [inline]
 RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:129 [inline]
 RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
 RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
 RIP: 0010:kasan_check_range+0x101/0x190 mm/kasan/generic.c:189
Code: 07 49 39 d1 75 0a 45 3a 11 b8 01 00 00 00 7c 0b 44 89 c2 e8 21 ed ff ff 83 f0 01 5b 5d 41 5c c3 48 85 d2 74 4f 48 01 ea eb 09 <48> 83 c0 01 48 39 d0 74 41 80 38 00 74 f2 eb b6 41 bc 08 00 00 00
RSP: 0018:ffffc90012dcf998 EFLAGS: 00000046
RAX: fffffbfff258af1e RBX: fffffbfff258af1f RCX: ffffffff8168eda3
RDX: fffffbfff258af1f RSI: 0000000000000004 RDI: ffffffff92c578f0
RBP: fffffbfff258af1e R08: 0000000000000000 R09: fffffbfff258af1e
R10: ffffffff92c578f3 R11: ffffffff8acbcbc0 R12: 0000000000000002
R13: ffff88806db38400 R14: 1ffff920025b9f42 R15: ffffffff92c578e8
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00994e078 CR3: 000000002c250000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
  instrument_atomic_read include/linux/instrumented.h:68 [inline]
  atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
  queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline]
  debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline]
  do_raw_spin_unlock+0x53/0x230 kernel/locking/spinlock_debug.c:141
  __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
  _raw_spin_unlock_irqrestore+0x22/0x70 kernel/locking/spinlock.c:194
  debug_object_activate+0x349/0x540 lib/debugobjects.c:726
  debug_work_activate kernel/workqueue.c:578 [inline]
  insert_work+0x30/0x230 kernel/workqueue.c:1650
  __queue_work+0x62e/0x11d0 kernel/workqueue.c:1802
  __queue_delayed_work+0x1bf/0x270 kernel/workqueue.c:1953
  queue_delayed_work_on+0x106/0x130 kernel/workqueue.c:1989
  queue_delayed_work include/linux/workqueue.h:563 [inline]
  schedule_delayed_work include/linux/workqueue.h:677 [inline]
  nsim_dev_trap_report_work+0x9c0/0xc80 drivers/net/netdevsim/dev.c:842
  process_one_work+0x886/0x15d0 kernel/workqueue.c:2633
  process_scheduled_works kernel/workqueue.c:2706 [inline]
  worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787
  kthread+0x2c6/0x3a0 kernel/kthread.c:388
  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
 </TASK>

The Linux kernel CVE team has assigned CVE-2024-26681 to this issue.

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

	Issue introduced in 6.0 with commit 012ec02ae441 and fixed in 6.1.78 with commit 0193e0660cc6
	Issue introduced in 6.0 with commit 012ec02ae441 and fixed in 6.6.17 with commit 6eecddd9c3c8
	Issue introduced in 6.0 with commit 012ec02ae441 and fixed in 6.7.5 with commit d91964cdada7
	Issue introduced in 6.0 with commit 012ec02ae441 and fixed in 6.8 with commit ba5e1272142d

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-2024-26681
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:
	drivers/net/netdevsim/dev.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/0193e0660cc6689c794794b471492923cfd7bfbc
	https://git.kernel.org/stable/c/6eecddd9c3c8d6e3a097531cdc6d500335b35e46
	https://git.kernel.org/stable/c/d91964cdada76740811b7c621239f9c407820dbc
	https://git.kernel.org/stable/c/ba5e1272142d051dcc57ca1d3225ad8a089f9858