ghsa-h2wx-vrp7-wvmw
Vulnerability from github
Published
2024-05-19 09:34
Modified
2024-10-27 15:30
Severity ?
4.4 (Medium) - CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
Details

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

smb: client: fix UAF in smb2_reconnect_server()

The UAF bug is due to smb2_reconnect_server() accessing a session that is already being teared down by another thread that is executing __cifs_put_smb_ses(). This can happen when (a) the client has connection to the server but no session or (b) another thread ends up setting @ses->ses_status again to something different than SES_EXITING.

To fix this, we need to make sure to unconditionally set @ses->ses_status to SES_EXITING and prevent any other threads from setting a new status while we're still tearing it down.

The following can be reproduced by adding some delay to right after the ipc is freed in __cifs_put_smb_ses() - which will give smb2_reconnect_server() worker a chance to run and then accessing @ses->ipc:

kinit ... mount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10 [disconnect srv] ls /mnt/1 &>/dev/null sleep 30 kdestroy [reconnect srv] sleep 10 umount /mnt/1 ... CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed CIFS: VFS: \srv Send error in SessSetup = -126 CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed CIFS: VFS: \srv Send error in SessSetup = -126 general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI CPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39 04/01/2014 Workqueue: cifsiod smb2_reconnect_server [cifs] RIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0 Code: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad de 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 <48> 8b 01 48 39 f8 75 7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8 RSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83 RAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b RDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800 RBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000 R13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000 FS: 0000000000000000(0000) GS:ffff888157c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: ? die_addr+0x36/0x90 ? exc_general_protection+0x1c1/0x3f0 ? asm_exc_general_protection+0x26/0x30 ? __list_del_entry_valid_or_report+0x33/0xf0 __cifs_put_smb_ses+0x1ae/0x500 [cifs] smb2_reconnect_server+0x4ed/0x710 [cifs] process_one_work+0x205/0x6b0 worker_thread+0x191/0x360 ? __pfx_worker_thread+0x10/0x10 kthread+0xe2/0x110 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30

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{
  "affected": [],
  "aliases": [
    "CVE-2024-35870"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-19T09:15:08Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix UAF in smb2_reconnect_server()\n\nThe UAF bug is due to smb2_reconnect_server() accessing a session that\nis already being teared down by another thread that is executing\n__cifs_put_smb_ses().  This can happen when (a) the client has\nconnection to the server but no session or (b) another thread ends up\nsetting @ses-\u003eses_status again to something different than\nSES_EXITING.\n\nTo fix this, we need to make sure to unconditionally set\n@ses-\u003eses_status to SES_EXITING and prevent any other threads from\nsetting a new status while we\u0027re still tearing it down.\n\nThe following can be reproduced by adding some delay to right after\nthe ipc is freed in __cifs_put_smb_ses() - which will give\nsmb2_reconnect_server() worker a chance to run and then accessing\n@ses-\u003eipc:\n\nkinit ...\nmount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10\n[disconnect srv]\nls /mnt/1 \u0026\u003e/dev/null\nsleep 30\nkdestroy\n[reconnect srv]\nsleep 10\numount /mnt/1\n...\nCIFS: VFS: Verify user has a krb5 ticket and keyutils is installed\nCIFS: VFS: \\\\srv Send error in SessSetup = -126\nCIFS: VFS: Verify user has a krb5 ticket and keyutils is installed\nCIFS: VFS: \\\\srv Send error in SessSetup = -126\ngeneral protection fault, probably for non-canonical address\n0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI\nCPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39\n04/01/2014\nWorkqueue: cifsiod smb2_reconnect_server [cifs]\nRIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0\nCode: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad\nde 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 \u003c48\u003e 8b 01 48 39 f8 75\n7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8\nRSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83\nRAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b\nRDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800\nRBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000\nR13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000\nFS: 0000000000000000(0000) GS:ffff888157c00000(0000)\nknlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n ? die_addr+0x36/0x90\n ? exc_general_protection+0x1c1/0x3f0\n ? asm_exc_general_protection+0x26/0x30\n ? __list_del_entry_valid_or_report+0x33/0xf0\n __cifs_put_smb_ses+0x1ae/0x500 [cifs]\n smb2_reconnect_server+0x4ed/0x710 [cifs]\n process_one_work+0x205/0x6b0\n worker_thread+0x191/0x360\n ? __pfx_worker_thread+0x10/0x10\n kthread+0xe2/0x110\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x34/0x50\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e",
  "id": "GHSA-h2wx-vrp7-wvmw",
  "modified": "2024-10-27T15:30:43Z",
  "published": "2024-05-19T09:34:46Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-35870"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24a9799aa8efecd0eb55a75e35f9d8e6400063aa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/45f2beda1f1bc3d962ec07db1ccc3197c25499a5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6202996a1c1887e83d0b3b0fcd86d0e5e6910ea0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}


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