{"id":"CVE-2024-53071","summary":"drm/panthor: Be stricter about IO mapping flags","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/panthor: Be stricter about IO mapping flags\n\nThe current panthor_device_mmap_io() implementation has two issues:\n\n1. For mapping DRM_PANTHOR_USER_FLUSH_ID_MMIO_OFFSET,\n   panthor_device_mmap_io() bails if VM_WRITE is set, but does not clear\n   VM_MAYWRITE. That means userspace can use mprotect() to make the mapping\n   writable later on. This is a classic Linux driver gotcha.\n   I don't think this actually has any impact in practice:\n   When the GPU is powered, writes to the FLUSH_ID seem to be ignored; and\n   when the GPU is not powered, the dummy_latest_flush page provided by the\n   driver is deliberately designed to not do any flushes, so the only thing\n   writing to the dummy_latest_flush could achieve would be to make *more*\n   flushes happen.\n\n2. panthor_device_mmap_io() does not block MAP_PRIVATE mappings (which are\n   mappings without the VM_SHARED flag).\n   MAP_PRIVATE in combination with VM_MAYWRITE indicates that the VMA has\n   copy-on-write semantics, which for VM_PFNMAP are semi-supported but\n   fairly cursed.\n   In particular, in such a mapping, the driver can only install PTEs\n   during mmap() by calling remap_pfn_range() (because remap_pfn_range()\n   wants to **store the physical address of the mapped physical memory into\n   the vm_pgoff of the VMA**); installing PTEs later on with a fault\n   handler (as panthor does) is not supported in private mappings, and so\n   if you try to fault in such a mapping, vmf_insert_pfn_prot() splats when\n   it hits a BUG() check.\n\nFix it by clearing the VM_MAYWRITE flag (userspace writing to the FLUSH_ID\ndoesn't make sense) and requiring VM_SHARED (copy-on-write semantics for\nthe FLUSH_ID don't make sense).\n\nReproducers for both scenarios are in the notes of my patch on the mailing\nlist; I tested that these bugs exist on a Rock 5B machine.\n\nNote that I only compile-tested the patch, I haven't tested it; I don't\nhave a working kernel build setup for the test machine yet. Please test it\nbefore applying it.","modified":"2026-04-02T12:22:43.023511Z","published":"2024-11-19T17:22:38.327Z","related":["USN-7276-1","USN-7277-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/53xxx/CVE-2024-53071.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2604afd65043e8f9d4be036cb1242adf6b5723cf"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f432a1621f049bb207e78363d9d0e3c6fa2da5db"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/53xxx/CVE-2024-53071.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-53071"},{"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":"5fe909cae118a757a77afb37174b99436a36d2e2"},{"fixed":"2604afd65043e8f9d4be036cb1242adf6b5723cf"},{"fixed":"f432a1621f049bb207e78363d9d0e3c6fa2da5db"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-53071.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}