{"id":"AZL-48656","summary":"CVE-2024-42063 affecting package kernel 5.15.200.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode\n\nsyzbot reported uninit memory usages during map_{lookup,delete}_elem.\n\n==========\nBUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]\nBUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796\n__dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]\ndev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796\n____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]\nbpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38\n___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997\n__bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237\n==========\n\nThe reproducer should be in the interpreter mode.\n\nThe C reproducer is trying to run the following bpf prog:\n\n    0: (18) r0 = 0x0\n    2: (18) r1 = map[id:49]\n    4: (b7) r8 = 16777216\n    5: (7b) *(u64 *)(r10 -8) = r8\n    6: (bf) r2 = r10\n    7: (07) r2 += -229\n            ^^^^^^^^^^\n\n    8: (b7) r3 = 8\n    9: (b7) r4 = 0\n   10: (85) call dev_map_lookup_elem#1543472\n   11: (95) exit\n\nIt is due to the \"void *key\" (r2) passed to the helper. bpf allows uninit\nstack memory access for bpf prog with the right privileges. This patch\nuses kmsan_unpoison_memory() to mark the stack as initialized.\n\nThis should address different syzbot reports on the uninit \"void *key\"\nargument during map_{lookup,delete}_elem.","modified":"2026-04-01T05:16:04.280994Z","published":"2024-07-29T16:15:06Z","upstream":["CVE-2024-42063"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-42063"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.15.200.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-48656.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"}]}