ghsa-rmff-fqq9-pc3q
Vulnerability from github
Published
2024-06-10 15:31
Modified
2024-09-05 18:30
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Details

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

af_unix: Update unix_sk(sk)->oob_skb under sk_receive_queue lock.

Billy Jheng Bing-Jhong reported a race between __unix_gc() and queue_oob().

__unix_gc() tries to garbage-collect close()d inflight sockets, and then if the socket has MSG_OOB in unix_sk(sk)->oob_skb, GC will drop the reference and set NULL to it locklessly.

However, the peer socket still can send MSG_OOB message and queue_oob() can update unix_sk(sk)->oob_skb concurrently, leading NULL pointer dereference. [0]

To fix the issue, let's update unix_sk(sk)->oob_skb under the sk_receive_queue's lock and take it everywhere we touch oob_skb.

Note that we defer kfree_skb() in manage_oob() to silence lockdep false-positive (See [1]).

[0]: BUG: kernel NULL pointer dereference, address: 0000000000000008 PF: supervisor write access in kernel mode PF: error_code(0x0002) - not-present page PGD 8000000009f5e067 P4D 8000000009f5e067 PUD 9f5d067 PMD 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc5-00191-gd091e579b864 #110 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: events delayed_fput RIP: 0010:skb_dequeue (./include/linux/skbuff.h:2386 ./include/linux/skbuff.h:2402 net/core/skbuff.c:3847) Code: 39 e3 74 3e 8b 43 10 48 89 ef 83 e8 01 89 43 10 49 8b 44 24 08 49 c7 44 24 08 00 00 00 00 49 8b 14 24 49 c7 04 24 00 00 00 00 <48> 89 42 08 48 89 10 e8 e7 c5 42 00 4c 89 e0 5b 5d 41 5c c3 cc cc RSP: 0018:ffffc900001bfd48 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff8880088f5ae8 RCX: 00000000361289f9 RDX: 0000000000000000 RSI: 0000000000000206 RDI: ffff8880088f5b00 RBP: ffff8880088f5b00 R08: 0000000000080000 R09: 0000000000000001 R10: 0000000000000003 R11: 0000000000000001 R12: ffff8880056b6a00 R13: ffff8880088f5280 R14: 0000000000000001 R15: ffff8880088f5a80 FS: 0000000000000000(0000) GS:ffff88807dd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000006314000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: unix_release_sock (net/unix/af_unix.c:654) unix_release (net/unix/af_unix.c:1050) __sock_release (net/socket.c:660) sock_close (net/socket.c:1423) __fput (fs/file_table.c:423) delayed_fput (fs/file_table.c:444 (discriminator 3)) process_one_work (kernel/workqueue.c:3259) worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) kthread (kernel/kthread.c:388) ret_from_fork (arch/x86/kernel/process.c:153) ret_from_fork_asm (arch/x86/entry/entry_64.S:257) Modules linked in: CR2: 0000000000000008

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{
  "affected": [],
  "aliases": [
    "CVE-2024-36972"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-06-10T15:15:52Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Update unix_sk(sk)-\u003eoob_skb under sk_receive_queue lock.\n\nBilly Jheng Bing-Jhong reported a race between __unix_gc() and\nqueue_oob().\n\n__unix_gc() tries to garbage-collect close()d inflight sockets,\nand then if the socket has MSG_OOB in unix_sk(sk)-\u003eoob_skb, GC\nwill drop the reference and set NULL to it locklessly.\n\nHowever, the peer socket still can send MSG_OOB message and\nqueue_oob() can update unix_sk(sk)-\u003eoob_skb concurrently, leading\nNULL pointer dereference. [0]\n\nTo fix the issue, let\u0027s update unix_sk(sk)-\u003eoob_skb under the\nsk_receive_queue\u0027s lock and take it everywhere we touch oob_skb.\n\nNote that we defer kfree_skb() in manage_oob() to silence lockdep\nfalse-positive (See [1]).\n\n[0]:\nBUG: kernel NULL pointer dereference, address: 0000000000000008\n PF: supervisor write access in kernel mode\n PF: error_code(0x0002) - not-present page\nPGD 8000000009f5e067 P4D 8000000009f5e067 PUD 9f5d067 PMD 0\nOops: 0002 [#1] PREEMPT SMP PTI\nCPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc5-00191-gd091e579b864 #110\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nWorkqueue: events delayed_fput\nRIP: 0010:skb_dequeue (./include/linux/skbuff.h:2386 ./include/linux/skbuff.h:2402 net/core/skbuff.c:3847)\nCode: 39 e3 74 3e 8b 43 10 48 89 ef 83 e8 01 89 43 10 49 8b 44 24 08 49 c7 44 24 08 00 00 00 00 49 8b 14 24 49 c7 04 24 00 00 00 00 \u003c48\u003e 89 42 08 48 89 10 e8 e7 c5 42 00 4c 89 e0 5b 5d 41 5c c3 cc cc\nRSP: 0018:ffffc900001bfd48 EFLAGS: 00000002\nRAX: 0000000000000000 RBX: ffff8880088f5ae8 RCX: 00000000361289f9\nRDX: 0000000000000000 RSI: 0000000000000206 RDI: ffff8880088f5b00\nRBP: ffff8880088f5b00 R08: 0000000000080000 R09: 0000000000000001\nR10: 0000000000000003 R11: 0000000000000001 R12: ffff8880056b6a00\nR13: ffff8880088f5280 R14: 0000000000000001 R15: ffff8880088f5a80\nFS:  0000000000000000(0000) GS:ffff88807dd80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000008 CR3: 0000000006314000 CR4: 00000000007506f0\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n unix_release_sock (net/unix/af_unix.c:654)\n unix_release (net/unix/af_unix.c:1050)\n __sock_release (net/socket.c:660)\n sock_close (net/socket.c:1423)\n __fput (fs/file_table.c:423)\n delayed_fput (fs/file_table.c:444 (discriminator 3))\n process_one_work (kernel/workqueue.c:3259)\n worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416)\n kthread (kernel/kthread.c:388)\n ret_from_fork (arch/x86/kernel/process.c:153)\n ret_from_fork_asm (arch/x86/entry/entry_64.S:257)\n \u003c/TASK\u003e\nModules linked in:\nCR2: 0000000000000008",
  "id": "GHSA-rmff-fqq9-pc3q",
  "modified": "2024-09-05T18:30:49Z",
  "published": "2024-06-10T15:31:02Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-36972"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4708f49add84a57ce0ccc7bf9a6269845c631cc3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4bf6964451c3cb411fbaa1ae8b214b3d97a59bf1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/518a994aa0b87d96f1bc6678a7035df5d1fcd7a1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9841991a446c87f90f66f4b9fee6fe934c1336a2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d59ae9314b97e01c76a4171472441e55721ba636"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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