CVE-2022-49775

Published May 1, 2025

Last updated 7 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: tcp: cdg: allow tcp_cdg_release() to be called multiple times Apparently, mptcp is able to call tcp_disconnect() on an already disconnected flow. This is generally fine, unless current congestion control is CDG, because it might trigger a double-free [1] Instead of fixing MPTCP, and future bugs, we can make tcp_disconnect() more resilient. [1] BUG: KASAN: double-free in slab_free mm/slub.c:3539 [inline] BUG: KASAN: double-free in kfree+0xe2/0x580 mm/slub.c:4567 CPU: 0 PID: 3645 Comm: kworker/0:7 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: events mptcp_worker Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report_invalid_free+0x81/0x190 mm/kasan/report.c:462 ____kasan_slab_free+0x18b/0x1c0 mm/kasan/common.c:356 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1759 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1785 slab_free mm/slub.c:3539 [inline] kfree+0xe2/0x580 mm/slub.c:4567 tcp_disconnect+0x980/0x1e20 net/ipv4/tcp.c:3145 __mptcp_close_ssk+0x5ca/0x7e0 net/mptcp/protocol.c:2327 mptcp_do_fastclose net/mptcp/protocol.c:2592 [inline] mptcp_worker+0x78c/0xff0 net/mptcp/protocol.c:2627 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> Allocated by task 3671: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:437 [inline] ____kasan_kmalloc mm/kasan/common.c:516 [inline] ____kasan_kmalloc mm/kasan/common.c:475 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525 kmalloc_array include/linux/slab.h:640 [inline] kcalloc include/linux/slab.h:671 [inline] tcp_cdg_init+0x10d/0x170 net/ipv4/tcp_cdg.c:380 tcp_init_congestion_control+0xab/0x550 net/ipv4/tcp_cong.c:193 tcp_reinit_congestion_control net/ipv4/tcp_cong.c:217 [inline] tcp_set_congestion_control+0x96c/0xaa0 net/ipv4/tcp_cong.c:391 do_tcp_setsockopt+0x505/0x2320 net/ipv4/tcp.c:3513 tcp_setsockopt+0xd4/0x100 net/ipv4/tcp.c:3801 mptcp_setsockopt+0x35f/0x2570 net/mptcp/sockopt.c:844 __sys_setsockopt+0x2d6/0x690 net/socket.c:2252 __do_sys_setsockopt net/socket.c:2263 [inline] __se_sys_setsockopt net/socket.c:2260 [inline] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2260 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 16: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:367 [inline] ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:329 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1759 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1785 slab_free mm/slub.c:3539 [inline] kfree+0xe2/0x580 mm/slub.c:4567 tcp_cleanup_congestion_control+0x70/0x120 net/ipv4/tcp_cong.c:226 tcp_v4_destroy_sock+0xdd/0x750 net/ipv4/tcp_ipv4.c:2254 tcp_v6_destroy_sock+0x11/0x20 net/ipv6/tcp_ipv6.c:1969 inet_csk_destroy_sock+0x196/0x440 net/ipv4/inet_connection_sock.c:1157 tcp_done+0x23b/0x340 net/ipv4/tcp.c:4649 tcp_rcv_state_process+0x40e7/0x4990 net/ipv4/tcp_input.c:6624 tcp_v6_do_rcv+0x3fc/0x13c0 net/ipv6/tcp_ipv6.c:1525 tcp_v6_rcv+0x2e8e/0x3830 net/ipv6/tcp_ipv6.c:1759 ip6_protocol_deliver_rcu+0x2db/0x1950 net/ipv6/ip6_input.c:439 ip6_input_finish+0x14c/0x2c0 net/ipv6/ip6_input.c:484 NF_HOOK include/linux/netfilter.h:302 [inline] NF_HOOK include/linux/netfilter.h:296 [inline] ip6_input+0x9c/0xd ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-415

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.CVE-2026-46272