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
.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 20.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux | < any | UNKNOWN |
ubuntu | 23.10 | noarch | linux | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 23.10 | noarch | linux-aws | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws-5.15 | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-aws-6.5 | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-azure | < any | UNKNOWN |
ubuntu | 22.04 | noarch | linux-azure | < any | UNKNOWN |
git.kernel.org/linus/7ddc21e317b360c3444de3023bcc83b85fabae2f (6.7-rc1)
git.kernel.org/stable/c/0dd34a7ad395dbcf6ae60e48e9786050e25b9bc5
git.kernel.org/stable/c/1734a79e951914f1db2c65e635012a35db1c674b
git.kernel.org/stable/c/1e901bcb8af19416b65f5063a4af7996e5a51d7f
git.kernel.org/stable/c/41aad9d6953984d134fc50f631f24ef476875d4d
git.kernel.org/stable/c/7ddc21e317b360c3444de3023bcc83b85fabae2f
git.kernel.org/stable/c/c7c26d0ef5d20f00dbb2ae3befcabbe0efa77275
launchpad.net/bugs/cve/CVE-2023-52854
nvd.nist.gov/vuln/detail/CVE-2023-52854
security-tracker.debian.org/tracker/CVE-2023-52854
www.cve.org/CVERecord?id=CVE-2023-52854