{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "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'll describe the problem scenario\nusing a simplified model:\n\nSuppose there's 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->done);\n}\n\nvoid user_function() {\n    DECLARE_COMPLETION(done)\n    padata->parallel = parallel;\n    padata->serial = serial;\n    padata_do_parallel();\n    wait_for_completion(&done);\n    padata_free_shell();\n}\n```\n\nIn the corresponding padata.c file, there's 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(&local_list)) {\n        ...\n        padata->serial(padata);\n        cnt++;\n    }\n\n    local_bh_enable();\n\n    if (refcount_sub_and_test(cnt, &pd->refcnt))\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->refcnt`,\n`pd` has already been released by `padata_free_shell()`, resulting\nin a UAF issue with `pd->refcnt`.\n\nThe fix is straightforward: add `refcount_dec_and_test` before calling\n`padata_free_pd` in `padata_free_shell`."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "kernel/padata.c"
               ],
               "versions": [
                  {
                     "version": "07928d9bfc81",
                     "lessThan": "41aad9d69539",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "07928d9bfc81",
                     "lessThan": "0dd34a7ad395",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "07928d9bfc81",
                     "lessThan": "c7c26d0ef5d2",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "07928d9bfc81",
                     "lessThan": "1e901bcb8af1",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "07928d9bfc81",
                     "lessThan": "1734a79e9519",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "07928d9bfc81",
                     "lessThan": "7ddc21e317b3",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "kernel/padata.c"
               ],
               "versions": [
                  {
                     "version": "5.6",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "5.6",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.201",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.139",
                     "lessThanOrEqual": "5.15.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.1.63",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.5.12",
                     "lessThanOrEqual": "6.5.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.2",
                     "lessThanOrEqual": "6.6.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.7",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/41aad9d6953984d134fc50f631f24ef476875d4d"
            },
            {
               "url": "https://git.kernel.org/stable/c/0dd34a7ad395dbcf6ae60e48e9786050e25b9bc5"
            },
            {
               "url": "https://git.kernel.org/stable/c/c7c26d0ef5d20f00dbb2ae3befcabbe0efa77275"
            },
            {
               "url": "https://git.kernel.org/stable/c/1e901bcb8af19416b65f5063a4af7996e5a51d7f"
            },
            {
               "url": "https://git.kernel.org/stable/c/1734a79e951914f1db2c65e635012a35db1c674b"
            },
            {
               "url": "https://git.kernel.org/stable/c/7ddc21e317b360c3444de3023bcc83b85fabae2f"
            }
         ],
         "title": "padata: Fix refcnt handling in padata_free_shell()",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2023-52854",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}