GHSA-547X-8CMF-V92W

Vulnerability from github – Published: 2025-03-17 18:31 – Updated: 2025-03-17 18:31
VLAI
Details

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

list: fix a data-race around ep->rdllist

ep_poll() first calls ep_events_available() with no lock held and checks if ep->rdllist is empty by list_empty_careful(), which reads rdllist->prev. Thus all accesses to it need some protection to avoid store/load-tearing.

Note INIT_LIST_HEAD_RCU() already has the annotation for both prev and next.

Commit bf3b9f6372c4 ("epoll: Add busy poll support to epoll with socket fds.") added the first lockless ep_events_available(), and commit c5a282e9635e ("fs/epoll: reduce the scope of wq lock in epoll_wait()") made some ep_events_available() calls lockless and added single call under a lock, finally commit e59d3c64cba6 ("epoll: eliminate unnecessary lock for zero timeout") made the last ep_events_available() lockless.

BUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait

write to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0: INIT_LIST_HEAD include/linux/list.h:38 [inline] list_splice_init include/linux/list.h:492 [inline] ep_start_scan fs/eventpoll.c:622 [inline] ep_send_events fs/eventpoll.c:1656 [inline] ep_poll fs/eventpoll.c:1806 [inline] do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1: list_empty_careful include/linux/list.h:329 [inline] ep_events_available fs/eventpoll.c:381 [inline] ep_poll fs/eventpoll.c:1797 [inline] do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff88810480c7d0 -> 0xffff888103c15098

Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G W 5.17.0-rc7-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2022-49443"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:01:20Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlist: fix a data-race around ep-\u003erdllist\n\nep_poll() first calls ep_events_available() with no lock held and checks\nif ep-\u003erdllist is empty by list_empty_careful(), which reads\nrdllist-\u003eprev.  Thus all accesses to it need some protection to avoid\nstore/load-tearing.\n\nNote INIT_LIST_HEAD_RCU() already has the annotation for both prev\nand next.\n\nCommit bf3b9f6372c4 (\"epoll: Add busy poll support to epoll with socket\nfds.\") added the first lockless ep_events_available(), and commit\nc5a282e9635e (\"fs/epoll: reduce the scope of wq lock in epoll_wait()\")\nmade some ep_events_available() calls lockless and added single call under\na lock, finally commit e59d3c64cba6 (\"epoll: eliminate unnecessary lock\nfor zero timeout\") made the last ep_events_available() lockless.\n\nBUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait\n\nwrite to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0:\n INIT_LIST_HEAD include/linux/list.h:38 [inline]\n list_splice_init include/linux/list.h:492 [inline]\n ep_start_scan fs/eventpoll.c:622 [inline]\n ep_send_events fs/eventpoll.c:1656 [inline]\n ep_poll fs/eventpoll.c:1806 [inline]\n do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234\n do_epoll_pwait fs/eventpoll.c:2268 [inline]\n __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]\n __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275\n __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nread to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1:\n list_empty_careful include/linux/list.h:329 [inline]\n ep_events_available fs/eventpoll.c:381 [inline]\n ep_poll fs/eventpoll.c:1797 [inline]\n do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234\n do_epoll_pwait fs/eventpoll.c:2268 [inline]\n __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]\n __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275\n __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nvalue changed: 0xffff88810480c7d0 -\u003e 0xffff888103c15098\n\nReported by Kernel Concurrency Sanitizer on:\nCPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G        W         5.17.0-rc7-syzkaller-dirty #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011",
  "id": "GHSA-547x-8cmf-v92w",
  "modified": "2025-03-17T18:31:47Z",
  "published": "2025-03-17T18:31:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49443"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5d5d993f16be15d124be7b8ec71b28ef7b7dc3af"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cb3e48f7a35033deb9455abe3932e63cb500b9eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d679ae94fdd5d3ab00c35078f5af5f37e068b03d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e039c0b5985999b150594126225e1ee51df7b4c9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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