ghsa-hrxv-7xrv-h5rv
Vulnerability from github
Published
2024-07-12 15:31
Modified
2024-07-12 15:31
Details

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

sock_map: avoid race between sock_map_close and sk_psock_put

sk_psock_get will return NULL if the refcount of psock has gone to 0, which will happen when the last call of sk_psock_put is done. However, sk_psock_drop may not have finished yet, so the close callback will still point to sock_map_close despite psock being NULL.

This can be reproduced with a thread deleting an element from the sock map, while the second one creates a socket, adds it to the map and closes it.

That will trigger the WARN_ON_ONCE:

------------[ cut here ]------------ WARNING: CPU: 1 PID: 7220 at net/core/sock_map.c:1701 sock_map_close+0x2a2/0x2d0 net/core/sock_map.c:1701 Modules linked in: CPU: 1 PID: 7220 Comm: syz-executor380 Not tainted 6.9.0-syzkaller-07726-g3c999d1ae3c7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:sock_map_close+0x2a2/0x2d0 net/core/sock_map.c:1701 Code: df e8 92 29 88 f8 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 79 29 88 f8 4c 8b 23 eb 89 e8 4f 15 23 f8 90 <0f> 0b 90 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 13 26 3d 02 RSP: 0018:ffffc9000441fda8 EFLAGS: 00010293 RAX: ffffffff89731ae1 RBX: ffffffff94b87540 RCX: ffff888029470000 RDX: 0000000000000000 RSI: ffffffff8bcab5c0 RDI: ffffffff8c1faba0 RBP: 0000000000000000 R08: ffffffff92f9b61f R09: 1ffffffff25f36c3 R10: dffffc0000000000 R11: fffffbfff25f36c4 R12: ffffffff89731840 R13: ffff88804b587000 R14: ffff88804b587000 R15: ffffffff89731870 FS: 000055555e080380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000207d4000 CR4: 0000000000350ef0 Call Trace: unix_release+0x87/0xc0 net/unix/af_unix.c:1048 __sock_release net/socket.c:659 [inline] sock_close+0xbe/0x240 net/socket.c:1421 __fput+0x42b/0x8a0 fs/file_table.c:422 __do_sys_close fs/open.c:1556 [inline] __se_sys_close fs/open.c:1541 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1541 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb37d618070 Code: 00 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d4 e8 10 2c 00 00 80 3d 31 f0 07 00 00 74 17 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c RSP: 002b:00007ffcd4a525d8 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fb37d618070 RDX: 0000000000000010 RSI: 00000000200001c0 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000100000000 R09: 0000000100000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Use sk_psock, which will only check that the pointer is not been set to NULL yet, which should only happen after the callbacks are restored. If, then, a reference can still be gotten, we may call sk_psock_stop and cancel psock->work.

As suggested by Paolo Abeni, reorder the condition so the control flow is less convoluted.

After that change, the reproducer does not trigger the WARN_ON_ONCE anymore.

Show details on source website

To clipboard 

{
   affected: [],
   aliases: [
      "CVE-2024-39500",
   ],
   database_specific: {
      cwe_ids: [],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2024-07-12T13:15:12Z",
      severity: null,
   },
   details: "In the Linux kernel, the following vulnerability has been resolved:\n\nsock_map: avoid race between sock_map_close and sk_psock_put\n\nsk_psock_get will return NULL if the refcount of psock has gone to 0, which\nwill happen when the last call of sk_psock_put is done. However,\nsk_psock_drop may not have finished yet, so the close callback will still\npoint to sock_map_close despite psock being NULL.\n\nThis can be reproduced with a thread deleting an element from the sock map,\nwhile the second one creates a socket, adds it to the map and closes it.\n\nThat will trigger the WARN_ON_ONCE:\n\n------------[ cut here ]------------\nWARNING: CPU: 1 PID: 7220 at net/core/sock_map.c:1701 sock_map_close+0x2a2/0x2d0 net/core/sock_map.c:1701\nModules linked in:\nCPU: 1 PID: 7220 Comm: syz-executor380 Not tainted 6.9.0-syzkaller-07726-g3c999d1ae3c7 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024\nRIP: 0010:sock_map_close+0x2a2/0x2d0 net/core/sock_map.c:1701\nCode: df e8 92 29 88 f8 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 79 29 88 f8 4c 8b 23 eb 89 e8 4f 15 23 f8 90 <0f> 0b 90 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 13 26 3d 02\nRSP: 0018:ffffc9000441fda8 EFLAGS: 00010293\nRAX: ffffffff89731ae1 RBX: ffffffff94b87540 RCX: ffff888029470000\nRDX: 0000000000000000 RSI: ffffffff8bcab5c0 RDI: ffffffff8c1faba0\nRBP: 0000000000000000 R08: ffffffff92f9b61f R09: 1ffffffff25f36c3\nR10: dffffc0000000000 R11: fffffbfff25f36c4 R12: ffffffff89731840\nR13: ffff88804b587000 R14: ffff88804b587000 R15: ffffffff89731870\nFS:  000055555e080380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000000 CR3: 00000000207d4000 CR4: 0000000000350ef0\nCall Trace:\n <TASK>\n unix_release+0x87/0xc0 net/unix/af_unix.c:1048\n __sock_release net/socket.c:659 [inline]\n sock_close+0xbe/0x240 net/socket.c:1421\n __fput+0x42b/0x8a0 fs/file_table.c:422\n __do_sys_close fs/open.c:1556 [inline]\n __se_sys_close fs/open.c:1541 [inline]\n __x64_sys_close+0x7f/0x110 fs/open.c:1541\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fb37d618070\nCode: 00 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d4 e8 10 2c 00 00 80 3d 31 f0 07 00 00 74 17 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c\nRSP: 002b:00007ffcd4a525d8 EFLAGS: 00000202 ORIG_RAX: 0000000000000003\nRAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fb37d618070\nRDX: 0000000000000010 RSI: 00000000200001c0 RDI: 0000000000000004\nRBP: 0000000000000000 R08: 0000000100000000 R09: 0000000100000000\nR10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000\nR13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000\n </TASK>\n\nUse sk_psock, which will only check that the pointer is not been set to\nNULL yet, which should only happen after the callbacks are restored. If,\nthen, a reference can still be gotten, we may call sk_psock_stop and cancel\npsock->work.\n\nAs suggested by Paolo Abeni, reorder the condition so the control flow is\nless convoluted.\n\nAfter that change, the reproducer does not trigger the WARN_ON_ONCE\nanymore.",
   id: "GHSA-hrxv-7xrv-h5rv",
   modified: "2024-07-12T15:31:26Z",
   published: "2024-07-12T15:31:26Z",
   references: [
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2024-39500",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/3627605de498639a3c586c8684d12c89cba11073",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/4959ffc65a0e94f8acaac20deac49f89e6ded52d",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/4b4647add7d3c8530493f7247d11e257ee425bf0",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/5eabdf17fed2ad41b836bb4055ec36d95e512c50",
      },
      {
         type: "WEB",
         url: "https://git.kernel.org/stable/c/e946428439a0d2079959f5603256ac51b6047017",
      },
   ],
   schema_version: "1.4.0",
   severity: [],
}


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