CVE-2021-47292 io_uring: fix memleak in io_init_wq_offload()

2024-05-2114:35:16

Linux

github.com

linux kernel

io_uring

memory leak

vulnerability

fix

hash_map

cve

AI Score

6.8

Confidence

Low

EPSS

Percentile

9.0%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

io_uring: fix memleak in io_init_wq_offload()

I got memory leak report when doing fuzz test:

BUG: memory leak
unreferenced object 0xffff888107310a80 (size 96):
comm “syz-executor.6”, pid 4610, jiffies 4295140240 (age 20.135s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 …N…
backtrace:
[<000000001974933b>] kmalloc include/linux/slab.h:591 [inline]
[<000000001974933b>] kzalloc include/linux/slab.h:721 [inline]
[<000000001974933b>] io_init_wq_offload fs/io_uring.c:7920 [inline]
[<000000001974933b>] io_uring_alloc_task_context+0x466/0x640 fs/io_uring.c:7955
[<0000000039d0800d>] __io_uring_add_tctx_node+0x256/0x360 fs/io_uring.c:9016
[<000000008482e78c>] io_uring_add_tctx_node fs/io_uring.c:9052 [inline]
[<000000008482e78c>] __do_sys_io_uring_enter fs/io_uring.c:9354 [inline]
[<000000008482e78c>] __se_sys_io_uring_enter fs/io_uring.c:9301 [inline]
[<000000008482e78c>] __x64_sys_io_uring_enter+0xabc/0xc20 fs/io_uring.c:9301
[<00000000b875f18f>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<00000000b875f18f>] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
[<000000006b0a8484>] entry_SYSCALL_64_after_hwframe+0x44/0xae

CPU0 CPU1
io_uring_enter io_uring_enter
io_uring_add_tctx_node io_uring_add_tctx_node
__io_uring_add_tctx_node __io_uring_add_tctx_node
io_uring_alloc_task_context io_uring_alloc_task_context
io_init_wq_offload io_init_wq_offload
hash = kzalloc hash = kzalloc
ctx->hash_map = hash ctx->hash_map = hash <- one of the hash is leaked

When calling io_uring_enter() in parallel, the ‘hash_map’ will be leaked,
add uring_lock to protect ‘hash_map’.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "e941894eae31",
        "lessThan": "502731a03f27",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e941894eae31",
        "lessThan": "362a9e652892",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/io_uring.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.12",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "5.13.6",
        "versionType": "custom",
        "lessThanOrEqual": "5.13.*"
      },
      {
        "status": "unaffected",
        "version": "5.14",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/io_uring.c"
    ],
    "defaultStatus": "affected"
  }
]