{"id":"CVE-2022-49840","summary":"bpf, test_run: Fix alignment problem in bpf_prog_test_run_skb()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, test_run: Fix alignment problem in bpf_prog_test_run_skb()\n\nWe got a syzkaller problem because of aarch64 alignment fault\nif KFENCE enabled. When the size from user bpf program is an odd\nnumber, like 399, 407, etc, it will cause the struct skb_shared_info's\nunaligned access. As seen below:\n\n  BUG: KFENCE: use-after-free read in __skb_clone+0x23c/0x2a0 net/core/skbuff.c:1032\n\n  Use-after-free read at 0xffff6254fffac077 (in kfence-#213):\n   __lse_atomic_add arch/arm64/include/asm/atomic_lse.h:26 [inline]\n   arch_atomic_add arch/arm64/include/asm/atomic.h:28 [inline]\n   arch_atomic_inc include/linux/atomic-arch-fallback.h:270 [inline]\n   atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline]\n   __skb_clone+0x23c/0x2a0 net/core/skbuff.c:1032\n   skb_clone+0xf4/0x214 net/core/skbuff.c:1481\n   ____bpf_clone_redirect net/core/filter.c:2433 [inline]\n   bpf_clone_redirect+0x78/0x1c0 net/core/filter.c:2420\n   bpf_prog_d3839dd9068ceb51+0x80/0x330\n   bpf_dispatcher_nop_func include/linux/bpf.h:728 [inline]\n   bpf_test_run+0x3c0/0x6c0 net/bpf/test_run.c:53\n   bpf_prog_test_run_skb+0x638/0xa7c net/bpf/test_run.c:594\n   bpf_prog_test_run kernel/bpf/syscall.c:3148 [inline]\n   __do_sys_bpf kernel/bpf/syscall.c:4441 [inline]\n   __se_sys_bpf+0xad0/0x1634 kernel/bpf/syscall.c:4381\n\n  kfence-#213: 0xffff6254fffac000-0xffff6254fffac196, size=407, cache=kmalloc-512\n\n  allocated by task 15074 on cpu 0 at 1342.585390s:\n   kmalloc include/linux/slab.h:568 [inline]\n   kzalloc include/linux/slab.h:675 [inline]\n   bpf_test_init.isra.0+0xac/0x290 net/bpf/test_run.c:191\n   bpf_prog_test_run_skb+0x11c/0xa7c net/bpf/test_run.c:512\n   bpf_prog_test_run kernel/bpf/syscall.c:3148 [inline]\n   __do_sys_bpf kernel/bpf/syscall.c:4441 [inline]\n   __se_sys_bpf+0xad0/0x1634 kernel/bpf/syscall.c:4381\n   __arm64_sys_bpf+0x50/0x60 kernel/bpf/syscall.c:4381\n\nTo fix the problem, we adjust @size so that (@size + @hearoom) is a\nmultiple of SMP_CACHE_BYTES. So we make sure the struct skb_shared_info\nis aligned to a cache line.","modified":"2026-04-11T12:44:35.286591Z","published":"2025-05-01T14:09:56.233Z","related":["SUSE-SU-2025:01983-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49840.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/047824a730699c6c66df43306b80f700c9dfc2fd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1b597f2d6a55e9f549989913860ad5170da04964"},{"type":"WEB","url":"https://git.kernel.org/stable/c/730fb1ef974a13915bc7651364d8b3318891cd70"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7a704dbfd3735304e261f2787c52fbc7c3884736"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d3fd203f36d46aa29600a72d57a1b61af80e4a25"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e60f37a1d379c821c17b08f366412dce9ef3d99f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eaa8edd86514afac9deb9bf9a5053e74f37edf40"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49840.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49840"},{"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":"1cf1cae963c2e6032aebe1637e995bc2f5d330f4"},{"fixed":"047824a730699c6c66df43306b80f700c9dfc2fd"},{"fixed":"730fb1ef974a13915bc7651364d8b3318891cd70"},{"fixed":"7a704dbfd3735304e261f2787c52fbc7c3884736"},{"fixed":"e60f37a1d379c821c17b08f366412dce9ef3d99f"},{"fixed":"eaa8edd86514afac9deb9bf9a5053e74f37edf40"},{"fixed":"1b597f2d6a55e9f549989913860ad5170da04964"},{"fixed":"d3fd203f36d46aa29600a72d57a1b61af80e4a25"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49840.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.12.0"},{"fixed":"4.14.300"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.15.0"},{"fixed":"4.19.267"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.225"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.156"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.80"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.0.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49840.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:H/I:H/A:H"}]}