CVE-2022-49018 mptcp: fix sleep in atomic at close time

What is CVE-2022-49018?

CVE-2022-49018 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Oct 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

mptcp: fix sleep in atomic at close time

Matt reported a splat at msk close time:

BUG: sleeping function called from invalid context at net/mptcp/protocol.c:2877 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 155, name: packetdrill preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 4 locks held by packetdrill/155: #0: ffff888001536990 (&sb->s_type->i_mutex_key#6){+.+.}-{3:3}, at: __sock_release (net/socket.c:650) #1: ffff88800b498130 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close (net/mptcp/protocol.c:2973) #2: ffff88800b49a130 (sk_lock-AF_INET/1){+.+.}-{0:0}, at: __mptcp_close_ssk (net/mptcp/protocol.c:2363) #3: ffff88800b49a0b0 (slock-AF_INET){+...}-{2:2}, at: __lock_sock_fast (include/net/sock.h:1820) Preemption disabled at: 0x0 CPU: 1 PID: 155 Comm: packetdrill Not tainted 6.1.0-rc5 #365 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) __might_resched.cold (kernel/sched/core.c:9891) __mptcp_destroy_sock (include/linux/kernel.h:110) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_subflow_queue_clean (include/net/sock.h:1777) __mptcp_close_ssk (net/mptcp/protocol.c:2363) mptcp_destroy_common (net/mptcp/protocol.c:3170) mptcp_destroy (include/net/sock.h:1495) __mptcp_destroy_sock (net/mptcp/protocol.c:2886) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_close (net/mptcp/protocol.c:2974) inet_release (net/ipv4/af_inet.c:432) __sock_release (net/socket.c:651) sock_close (net/socket.c:1367) __fput (fs/file_table.c:320) task_work_run (kernel/task_work.c:181 (discriminator 1)) exit_to_user_mode_prepare (include/linux/resume_user_mode.h:49) syscall_exit_to_user_mode (kernel/entry/common.c:130) do_syscall_64 (arch/x86/entry/common.c:87) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)

We can't call mptcp_close under the 'fast' socket lock variant, replace it with a sock_lock_nested() as the relevant code is already under the listening msk socket lock protection.

Weakness: CWE-667

Which versions are affected by CVE-2022-49018?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-49018?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2022-49018 being exploited?

There is no known exploitation of CVE-2022-49018 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2022-49018, GHSA-67rw-g94p-phv8, UBUNTU-CVE-2022-49018.