GHSA-3PPH-X43C-2V7F

Vulnerability from github – Published: 2024-08-26 12:31 – Updated: 2025-11-04 00:31
VLAI?
Details

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

net: bridge: mcast: wait for previous gc cycles when removing port

syzbot hit a use-after-free[1] which is caused because the bridge doesn't make sure that all previous garbage has been collected when removing a port. What happens is: CPU 1 CPU 2 start gc cycle remove port acquire gc lock first wait for lock call br_multicasg_gc() directly acquire lock now but free port the port can be freed while grp timers still running

Make sure all previous gc cycles have finished by using flush_work before freeing the port.

[1] BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699

CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437

Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2024-44934"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-08-26T11:15:05Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mcast: wait for previous gc cycles when removing port\n\nsyzbot hit a use-after-free[1] which is caused because the bridge doesn\u0027t\nmake sure that all previous garbage has been collected when removing a\nport. What happens is:\n      CPU 1                   CPU 2\n start gc cycle           remove port\n                         acquire gc lock first\n wait for lock\n                         call br_multicasg_gc() directly\n acquire lock now but    free port\n the port can be freed\n while grp timers still\n running\n\nMake sure all previous gc cycles have finished by using flush_work before\nfreeing the port.\n\n[1]\n  BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861\n  Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699\n\n  CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0\n  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024\n  Call Trace:\n   \u003cIRQ\u003e\n   __dump_stack lib/dump_stack.c:88 [inline]\n   dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114\n   print_address_description mm/kasan/report.c:377 [inline]\n   print_report+0xc3/0x620 mm/kasan/report.c:488\n   kasan_report+0xd9/0x110 mm/kasan/report.c:601\n   br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861\n   call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792\n   expire_timers kernel/time/timer.c:1843 [inline]\n   __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417\n   __run_timer_base kernel/time/timer.c:2428 [inline]\n   __run_timer_base kernel/time/timer.c:2421 [inline]\n   run_timer_base+0x111/0x190 kernel/time/timer.c:2437",
  "id": "GHSA-3pph-x43c-2v7f",
  "modified": "2025-11-04T00:31:18Z",
  "published": "2024-08-26T12:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-44934"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d8b26e10e680c01522d7cc14abe04c3265a928f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1e16828020c674b3be85f52685e8b80f9008f50f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/92c4ee25208d0f35dafc3213cdf355fbe449e078"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b2f794b168cf560682ff976b255aa6d29d14a658"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e3145ca904fa8dbfd1a5bf0187905bc117b0efce"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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