发布于3月6日3月6日 Members Ubuntu: (CVE-2023-52854): linux vulnerability Severity 4 CVSS (AV:L/AC:M/Au:N/C:P/I:P/A:P) Published 05/21/2024 Created 11/21/2024 Added 11/19/2024 Modified 02/11/2025 Description 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`. Solution(s) ubuntu-upgrade-linux ubuntu-upgrade-linux-aws ubuntu-upgrade-linux-aws-5-15 ubuntu-upgrade-linux-aws-fips ubuntu-upgrade-linux-azure ubuntu-upgrade-linux-azure-5-15 ubuntu-upgrade-linux-azure-fde ubuntu-upgrade-linux-azure-fde-5-15 ubuntu-upgrade-linux-bluefield ubuntu-upgrade-linux-fips ubuntu-upgrade-linux-gcp ubuntu-upgrade-linux-gcp-5-15 ubuntu-upgrade-linux-gcp-fips ubuntu-upgrade-linux-gke ubuntu-upgrade-linux-gkeop ubuntu-upgrade-linux-gkeop-5-15 ubuntu-upgrade-linux-hwe-5-15 ubuntu-upgrade-linux-ibm ubuntu-upgrade-linux-ibm-5-15 ubuntu-upgrade-linux-intel-iot-realtime ubuntu-upgrade-linux-intel-iotg ubuntu-upgrade-linux-intel-iotg-5-15 ubuntu-upgrade-linux-kvm ubuntu-upgrade-linux-lowlatency ubuntu-upgrade-linux-lowlatency-hwe-5-15 ubuntu-upgrade-linux-nvidia ubuntu-upgrade-linux-nvidia-6-5 ubuntu-upgrade-linux-oracle ubuntu-upgrade-linux-oracle-5-15 ubuntu-upgrade-linux-raspi ubuntu-upgrade-linux-realtime ubuntu-upgrade-linux-riscv-5-15 ubuntu-upgrade-linux-xilinx-zynqmp References https://attackerkb.com/topics/cve-2023-52854 CVE - 2023-52854 https://git.kernel.org/linus/7ddc21e317b360c3444de3023bcc83b85fabae2f https://git.kernel.org/stable/c/0dd34a7ad395dbcf6ae60e48e9786050e25b9bc5 https://git.kernel.org/stable/c/1734a79e951914f1db2c65e635012a35db1c674b https://git.kernel.org/stable/c/1e901bcb8af19416b65f5063a4af7996e5a51d7f https://git.kernel.org/stable/c/41aad9d6953984d134fc50f631f24ef476875d4d https://git.kernel.org/stable/c/7ddc21e317b360c3444de3023bcc83b85fabae2f https://git.kernel.org/stable/c/c7c26d0ef5d20f00dbb2ae3befcabbe0efa77275 https://www.cve.org/CVERecord?id=CVE-2023-52854 View more
