CVE-2021-47569 io_uring: fail cancellation for EXITING tasks

2024-05-2415:12:55

Linux

www.cve.org

linux kernel vulnerability

cve-2021-47569

io_uring

cancellation handling

security issue

6.3 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.0%

JSON

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

io_uring: fail cancellation for EXITING tasks

WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0
Workqueue: events io_fallback_req_func
RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
Call Trace:
<TASK>
io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886
io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>

We need original task’s context to do cancellations, so if it’s dying
and the callback is executed in a fallback mode, fail the cancellation
attempt.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/io_uring.c"
    ],
    "versions": [
      {
        "version": "89b263f6d56e",
        "lessThan": "3d2a1e68fd99",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "89b263f6d56e",
        "lessThan": "617a89484deb",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/io_uring.c"
    ],
    "versions": [
      {
        "version": "5.15",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.15",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.6",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]