{"id":"CVE-2022-49567","summary":"mm/mempolicy: fix uninit-value in mpol_rebind_policy()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mempolicy: fix uninit-value in mpol_rebind_policy()\n\nmpol_set_nodemask()(mm/mempolicy.c) does not set up nodemask when\npol-\u003emode is MPOL_LOCAL.  Check pol-\u003emode before access\npol-\u003ew.cpuset_mems_allowed in mpol_rebind_policy()(mm/mempolicy.c).\n\nBUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:352 [inline]\nBUG: KMSAN: uninit-value in mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368\n mpol_rebind_policy mm/mempolicy.c:352 [inline]\n mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368\n cpuset_change_task_nodemask kernel/cgroup/cpuset.c:1711 [inline]\n cpuset_attach+0x787/0x15e0 kernel/cgroup/cpuset.c:2278\n cgroup_migrate_execute+0x1023/0x1d20 kernel/cgroup/cgroup.c:2515\n cgroup_migrate kernel/cgroup/cgroup.c:2771 [inline]\n cgroup_attach_task+0x540/0x8b0 kernel/cgroup/cgroup.c:2804\n __cgroup1_procs_write+0x5cc/0x7a0 kernel/cgroup/cgroup-v1.c:520\n cgroup1_tasks_write+0x94/0xb0 kernel/cgroup/cgroup-v1.c:539\n cgroup_file_write+0x4c2/0x9e0 kernel/cgroup/cgroup.c:3852\n kernfs_fop_write_iter+0x66a/0x9f0 fs/kernfs/file.c:296\n call_write_iter include/linux/fs.h:2162 [inline]\n new_sync_write fs/read_write.c:503 [inline]\n vfs_write+0x1318/0x2030 fs/read_write.c:590\n ksys_write+0x28b/0x510 fs/read_write.c:643\n __do_sys_write fs/read_write.c:655 [inline]\n __se_sys_write fs/read_write.c:652 [inline]\n __x64_sys_write+0xdb/0x120 fs/read_write.c:652\n do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nUninit was created at:\n slab_post_alloc_hook mm/slab.h:524 [inline]\n slab_alloc_node mm/slub.c:3251 [inline]\n slab_alloc mm/slub.c:3259 [inline]\n kmem_cache_alloc+0x902/0x11c0 mm/slub.c:3264\n mpol_new mm/mempolicy.c:293 [inline]\n do_set_mempolicy+0x421/0xb70 mm/mempolicy.c:853\n kernel_set_mempolicy mm/mempolicy.c:1504 [inline]\n __do_sys_set_mempolicy mm/mempolicy.c:1510 [inline]\n __se_sys_set_mempolicy+0x44c/0xb60 mm/mempolicy.c:1507\n __x64_sys_set_mempolicy+0xd8/0x110 mm/mempolicy.c:1507\n do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nKMSAN: uninit-value in mpol_rebind_task (2)\nhttps://syzkaller.appspot.com/bug?id=d6eb90f952c2a5de9ea718a1b873c55cb13b59dc\n\nThis patch seems to fix below bug too.\nKMSAN: uninit-value in mpol_rebind_mm (2)\nhttps://syzkaller.appspot.com/bug?id=f2fecd0d7013f54ec4162f60743a2b28df40926b\n\nThe uninit-value is pol-\u003ew.cpuset_mems_allowed in mpol_rebind_policy().\nWhen syzkaller reproducer runs to the beginning of mpol_new(),\n\n\t    mpol_new() mm/mempolicy.c\n\t  do_mbind() mm/mempolicy.c\n\tkernel_mbind() mm/mempolicy.c\n\n`mode` is 1(MPOL_PREFERRED), nodes_empty(*nodes) is `true` and `flags`\nis 0. Then\n\n\tmode = MPOL_LOCAL;\n\t...\n\tpolicy-\u003emode = mode;\n\tpolicy-\u003eflags = flags;\n\nwill be executed. So in mpol_set_nodemask(),\n\n\t    mpol_set_nodemask() mm/mempolicy.c\n\t  do_mbind()\n\tkernel_mbind()\n\npol-\u003emode is 4 (MPOL_LOCAL), that `nodemask` in `pol` is not initialized,\nwhich will be accessed in mpol_rebind_policy().","modified":"2026-08-12T03:51:21.339544140Z","published":"2025-02-26T02:23:12.222Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49567.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/018160ad314d75b1409129b2247b614a9f35894c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/777e563f10e91e91130fe06bee85220d508e7b9b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8c5429a04ccd8dbcc3c753dab2f4126774ec28d4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49567.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49567"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"7858d7bca7fbbbbd5b940d2ec371b2d060b21b84"},{"fixed":"8c5429a04ccd8dbcc3c753dab2f4126774ec28d4"},{"fixed":"777e563f10e91e91130fe06bee85220d508e7b9b"},{"fixed":"018160ad314d75b1409129b2247b614a9f35894c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49567.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.14.0"},{"fixed":"5.15.58"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"5.18.15"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49567.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}