ghsa-gj4h-wmhg-vp66
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
padata: Fix refcnt handling in padata_free_shell()
In a high-load arm64 environment, the pcrypt_aead01 test in LTP can lead to system UAF (Use-After-Free) issues. Due to the lengthy analysis of the pcrypt_aead01 function call, I'll describe the problem scenario using a simplified model:
Suppose there's a user of padata named user_function that adheres to
the padata requirement of calling padata_free_shell after serial()
has been invoked, as demonstrated in the following code:
```c struct request { struct padata_priv padata; struct completion *done; };
void parallel(struct padata_priv *padata) { do_something(); }
void serial(struct padata_priv padata) { struct request request = container_of(padata, struct request, padata); complete(request->done); }
void user_function() { DECLARE_COMPLETION(done) padata->parallel = parallel; padata->serial = serial; padata_do_parallel(); wait_for_completion(&done); padata_free_shell(); } ```
In the corresponding padata.c file, there's the following code:
```c static void padata_serial_worker(struct work_struct *serial_work) { ... cnt = 0;
while (!list_empty(&local_list)) {
...
padata->serial(padata);
cnt++;
}
local_bh_enable();
if (refcount_sub_and_test(cnt, &pd->refcnt))
padata_free_pd(pd);
} ```
Because of the high system load and the accumulation of unexecuted
softirq at this moment, local_bh_enable() in padata takes longer
to execute than usual. Subsequently, when accessing pd->refcnt,
pd has already been released by padata_free_shell(), resulting
in a UAF issue with pd->refcnt.
The fix is straightforward: add refcount_dec_and_test before calling
padata_free_pd in padata_free_shell.
{
"affected": [],
"aliases": [
"CVE-2023-52854"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-21T16:15:22Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npadata: Fix refcnt handling in padata_free_shell()\n\nIn a high-load arm64 environment, the pcrypt_aead01 test in LTP can lead\nto system UAF (Use-After-Free) issues. Due to the lengthy analysis of\nthe pcrypt_aead01 function call, I\u0027ll describe the problem scenario\nusing a simplified model:\n\nSuppose there\u0027s a user of padata named `user_function` that adheres to\nthe padata requirement of calling `padata_free_shell` after `serial()`\nhas been invoked, as demonstrated in the following code:\n\n```c\nstruct request {\n struct padata_priv padata;\n struct completion *done;\n};\n\nvoid parallel(struct padata_priv *padata) {\n do_something();\n}\n\nvoid serial(struct padata_priv *padata) {\n struct request *request = container_of(padata,\n \t\t\t\tstruct request,\n\t\t\t\tpadata);\n complete(request-\u003edone);\n}\n\nvoid user_function() {\n DECLARE_COMPLETION(done)\n padata-\u003eparallel = parallel;\n padata-\u003eserial = serial;\n padata_do_parallel();\n wait_for_completion(\u0026done);\n padata_free_shell();\n}\n```\n\nIn the corresponding padata.c file, there\u0027s the following code:\n\n```c\nstatic void padata_serial_worker(struct work_struct *serial_work) {\n ...\n cnt = 0;\n\n while (!list_empty(\u0026local_list)) {\n ...\n padata-\u003eserial(padata);\n cnt++;\n }\n\n local_bh_enable();\n\n if (refcount_sub_and_test(cnt, \u0026pd-\u003erefcnt))\n padata_free_pd(pd);\n}\n```\n\nBecause of the high system load and the accumulation of unexecuted\nsoftirq at this moment, `local_bh_enable()` in padata takes longer\nto execute than usual. Subsequently, when accessing `pd-\u003erefcnt`,\n`pd` has already been released by `padata_free_shell()`, resulting\nin a UAF issue with `pd-\u003erefcnt`.\n\nThe fix is straightforward: add `refcount_dec_and_test` before calling\n`padata_free_pd` in `padata_free_shell`.",
"id": "GHSA-gj4h-wmhg-vp66",
"modified": "2024-05-21T18:31:23Z",
"published": "2024-05-21T18:31:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52854"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0dd34a7ad395dbcf6ae60e48e9786050e25b9bc5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1734a79e951914f1db2c65e635012a35db1c674b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1e901bcb8af19416b65f5063a4af7996e5a51d7f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/41aad9d6953984d134fc50f631f24ef476875d4d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7ddc21e317b360c3444de3023bcc83b85fabae2f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c7c26d0ef5d20f00dbb2ae3befcabbe0efa77275"
}
],
"schema_version": "1.4.0",
"severity": []
}
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.