ghsa-m923-55g6-m66q
Vulnerability from github
Published
2024-05-01 06:31
Modified
2024-06-26 00:31
Details

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

wireguard: netlink: check for dangling peer via is_dead instead of empty list

If all peers are removed via wg_peer_remove_all(), rather than setting peer_list to empty, the peer is added to a temporary list with a head on the stack of wg_peer_remove_all(). If a netlink dump is resumed and the cursored peer is one that has been removed via wg_peer_remove_all(), it will iterate from that peer and then attempt to dump freed peers.

Fix this by instead checking peer->is_dead, which was explictly created for this purpose. Also move up the device_update_lock lockdep assertion, since reading is_dead relies on that.

It can be reproduced by a small script like:

echo "Setting config..."
ip link add dev wg0 type wireguard
wg setconf wg0 /big-config
(
        while true; do
                echo "Showing config..."
                wg showconf wg0 > /dev/null
        done
) &
sleep 4
wg setconf wg0 <(printf "[Peer]\nPublicKey=$(wg genkey)\n")

Resulting in:

BUG: KASAN: slab-use-after-free in __lock_acquire+0x182a/0x1b20
Read of size 8 at addr ffff88811956ec70 by task wg/59
CPU: 2 PID: 59 Comm: wg Not tainted 6.8.0-rc2-debug+ #5
Call Trace:
 <TASK>
 dump_stack_lvl+0x47/0x70
 print_address_description.constprop.0+0x2c/0x380
 print_report+0xab/0x250
 kasan_report+0xba/0xf0
 __lock_acquire+0x182a/0x1b20
 lock_acquire+0x191/0x4b0
 down_read+0x80/0x440
 get_peer+0x140/0xcb0
 wg_get_device_dump+0x471/0x1130
Show details on source website

To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-26951"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-01T06:15:11Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwireguard: netlink: check for dangling peer via is_dead instead of empty list\n\nIf all peers are removed via wg_peer_remove_all(), rather than setting\npeer_list to empty, the peer is added to a temporary list with a head on\nthe stack of wg_peer_remove_all(). If a netlink dump is resumed and the\ncursored peer is one that has been removed via wg_peer_remove_all(), it\nwill iterate from that peer and then attempt to dump freed peers.\n\nFix this by instead checking peer-\u003eis_dead, which was explictly created\nfor this purpose. Also move up the device_update_lock lockdep assertion,\nsince reading is_dead relies on that.\n\nIt can be reproduced by a small script like:\n\n    echo \"Setting config...\"\n    ip link add dev wg0 type wireguard\n    wg setconf wg0 /big-config\n    (\n            while true; do\n                    echo \"Showing config...\"\n                    wg showconf wg0 \u003e /dev/null\n            done\n    ) \u0026\n    sleep 4\n    wg setconf wg0 \u003c(printf \"[Peer]\\nPublicKey=$(wg genkey)\\n\")\n\nResulting in:\n\n    BUG: KASAN: slab-use-after-free in __lock_acquire+0x182a/0x1b20\n    Read of size 8 at addr ffff88811956ec70 by task wg/59\n    CPU: 2 PID: 59 Comm: wg Not tainted 6.8.0-rc2-debug+ #5\n    Call Trace:\n     \u003cTASK\u003e\n     dump_stack_lvl+0x47/0x70\n     print_address_description.constprop.0+0x2c/0x380\n     print_report+0xab/0x250\n     kasan_report+0xba/0xf0\n     __lock_acquire+0x182a/0x1b20\n     lock_acquire+0x191/0x4b0\n     down_read+0x80/0x440\n     get_peer+0x140/0xcb0\n     wg_get_device_dump+0x471/0x1130",
  "id": "GHSA-m923-55g6-m66q",
  "modified": "2024-06-26T00:31:38Z",
  "published": "2024-05-01T06:31:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26951"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/13d107794304306164481d31ce33f8fdb25a9c04"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/302b2dfc013baca3dea7ceda383930d9297d231d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/55b6c738673871c9b0edae05d0c97995c1ff08c4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/710a177f347282eea162aec8712beb1f42d5ad87"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7bedfe4cfa38771840a355970e4437cd52d4046b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b7cea3a9af0853fdbb1b16633a458f991dde6aac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f52be46e3e6ecefc2539119784324f0cbc09620a"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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