{"id":"CVE-2024-57877","summary":"arm64: ptrace: fix partial SETREGSET for NT_ARM_POE","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: ptrace: fix partial SETREGSET for NT_ARM_POE\n\nCurrently poe_set() doesn't initialize the temporary 'ctrl' variable,\nand a SETREGSET call with a length of zero will leave this\nuninitialized. Consequently an arbitrary value will be written back to\ntarget-\u003ethread.por_el0, potentially leaking up to 64 bits of memory from\nthe kernel stack. The read is limited to a specific slot on the stack,\nand the issue does not provide a write mechanism.\n\nFix this by initializing the temporary value before copying the regset\nfrom userspace, as for other regsets (e.g. NT_PRSTATUS, NT_PRFPREG,\nNT_ARM_SYSTEM_CALL). In the case of a zero-length write, the existing\ncontents of POR_EL1 will be retained.\n\nBefore this patch:\n\n| # ./poe-test\n| Attempting to write NT_ARM_POE::por_el0 = 0x900d900d900d900d\n| SETREGSET(nt=0x40f, len=8) wrote 8 bytes\n|\n| Attempting to read NT_ARM_POE::por_el0\n| GETREGSET(nt=0x40f, len=8) read 8 bytes\n| Read NT_ARM_POE::por_el0 = 0x900d900d900d900d\n|\n| Attempting to write NT_ARM_POE (zero length)\n| SETREGSET(nt=0x40f, len=0) wrote 0 bytes\n|\n| Attempting to read NT_ARM_POE::por_el0\n| GETREGSET(nt=0x40f, len=8) read 8 bytes\n| Read NT_ARM_POE::por_el0 = 0xffff8000839c3d50\n\nAfter this patch:\n\n| # ./poe-test\n| Attempting to write NT_ARM_POE::por_el0 = 0x900d900d900d900d\n| SETREGSET(nt=0x40f, len=8) wrote 8 bytes\n|\n| Attempting to read NT_ARM_POE::por_el0\n| GETREGSET(nt=0x40f, len=8) read 8 bytes\n| Read NT_ARM_POE::por_el0 = 0x900d900d900d900d\n|\n| Attempting to write NT_ARM_POE (zero length)\n| SETREGSET(nt=0x40f, len=0) wrote 0 bytes\n|\n| Attempting to read NT_ARM_POE::por_el0\n| GETREGSET(nt=0x40f, len=8) read 8 bytes\n| Read NT_ARM_POE::por_el0 = 0x900d900d900d900d","modified":"2026-05-28T03:54:06.974464040Z","published":"2025-01-11T14:49:03.297Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/57xxx/CVE-2024-57877.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4105dd76bc8ad6529d47157ef0565cb84ca6676c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/594bfc4947c4fcabba1318d8384c61a29a6b89fb"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/57xxx/CVE-2024-57877.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-57877"},{"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":"17519819926211e6b2834e00e4554bec0daf22ac"},{"fixed":"4105dd76bc8ad6529d47157ef0565cb84ca6676c"},{"fixed":"594bfc4947c4fcabba1318d8384c61a29a6b89fb"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-57877.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.12.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-57877.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:L/I:N/A:H"}]}