{"id":"CVE-2022-49067","summary":"powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit","details":"In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit\n\nmpe: On 64-bit Book3E vmalloc space starts at 0x8000000000000000.\n\nBecause of the way __pa() works we have:\n  __pa(0x8000000000000000) == 0, and therefore\n  virt_to_pfn(0x8000000000000000) == 0, and therefore\n  virt_addr_valid(0x8000000000000000) == true\n\nWhich is wrong, virt_addr_valid() should be false for vmalloc space.\nIn fact all vmalloc addresses that alias with a valid PFN will return\ntrue from virt_addr_valid(). That can cause bugs with hardened usercopy\nas described below by Kefeng Wang:\n\n  When running ethtool eth0 on 64-bit Book3E, a BUG occurred:\n\n    usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!\n    kernel BUG at mm/usercopy.c:99\n    ...\n    usercopy_abort+0x64/0xa0 (unreliable)\n    __check_heap_object+0x168/0x190\n    __check_object_size+0x1a0/0x200\n    dev_ethtool+0x2494/0x2b20\n    dev_ioctl+0x5d0/0x770\n    sock_do_ioctl+0xf0/0x1d0\n    sock_ioctl+0x3ec/0x5a0\n    __se_sys_ioctl+0xf0/0x160\n    system_call_exception+0xfc/0x1f0\n    system_call_common+0xf8/0x200\n\n  The code shows below,\n\n    data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));\n    copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))\n\n  The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true\n  on 64-bit Book3E, which leads to the panic.\n\n  As commit 4dd7554a6456 (\"powerpc/64: Add VIRTUAL_BUG_ON checks for __va\n  and __pa addresses\") does, make sure the virt addr above PAGE_OFFSET in\n  the virt_addr_valid() for 64-bit, also add upper limit check to make\n  sure the virt is below high_memory.\n\n  Meanwhile, for 32-bit PAGE_OFFSET is the virtual address of the start\n  of lowmem, high_memory is the upper low virtual address, the check is\n  suitable for 32-bit, this will fix the issue mentioned in commit\n  602946ec2f90 (\"powerpc: Set max_mapnr correctly\") too.\n\nOn 32-bit there is a similar problem with high memory, that was fixed in\ncommit 602946ec2f90 (\"powerpc: Set max_mapnr correctly\"), but that\ncommit breaks highmem and needs to be reverted.\n\nWe can't easily fix __pa(), we have code that relies on its current\nbehaviour. So for now add extra checks to virt_addr_valid().\n\nFor 64-bit Book3S the extra checks are not necessary, the combination of\nvirt_to_pfn() and pfn_valid() should yield the correct result, but they\nare harmless.\n\n[mpe: Add additional change log detail]","modified":"2026-04-11T12:43:30.658700Z","published":"2025-02-26T01:54:34.862Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49067.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/a3727c25eacd7e437c4f560957fa3a376fe93e6b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cbc065efcba000ad8f615f506ebe61b6d3c5145b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d36febbcd537fcc50284e8b89609632d0146529f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/deab81144d5a043f42804207fb76cfbd8a806978"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fddb88bd266f4513abab7c36bca98935c9148a98"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ffa0b64e3be58519ae472ea29a1a1ad681e32f48"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49067.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49067"},{"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":"ffda09a9941c18d9f08d1176d55588d505f62912"},{"fixed":"deab81144d5a043f42804207fb76cfbd8a806978"},{"fixed":"d36febbcd537fcc50284e8b89609632d0146529f"},{"fixed":"fddb88bd266f4513abab7c36bca98935c9148a98"},{"fixed":"a3727c25eacd7e437c4f560957fa3a376fe93e6b"},{"fixed":"cbc065efcba000ad8f615f506ebe61b6d3c5145b"},{"fixed":"ffa0b64e3be58519ae472ea29a1a1ad681e32f48"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49067.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.4.0"},{"fixed":"5.4.190"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"5.16.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.17.0"},{"fixed":"5.17.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49067.json"}}],"schema_version":"1.7.5"}