From 593980175389a05793f6060aa20e626330960395 Mon Sep 17 00:00:00 2001 From: Guannan Wang Date: Thu, 14 May 2026 15:44:54 +0800 Subject: bpf: Use array_map_meta_equal for percpu array inner map replacement percpu_array_map_ops.map_meta_equal points to the generic bpf_map_meta_equal(), which does not compare max_entries. When a percpu array serves as an inner map, replacing it with one that has fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup() inlines the original template's index_mask as a JIT immediate, a lookup on the replacement map can access pptrs[] out of bounds. Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(), which already enforces the max_entries equality check. Add a selftest to verify that replacing a percpu array inner map with a differently-sized one is rejected. Fixes: db69718b8efa ("bpf: inline bpf_map_lookup_elem() for PERCPU_ARRAY maps") Signed-off-by: Guannan Wang Acked-by: Mykyta Yatsenko Link: https://lore.kernel.org/r/20260514074454.77491-1-wgnbuaa@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/arraymap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/bpf/arraymap.c') diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 5e25e0353509..dfb2110ab733 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -827,7 +827,7 @@ const struct bpf_map_ops array_map_ops = { }; const struct bpf_map_ops percpu_array_map_ops = { - .map_meta_equal = bpf_map_meta_equal, + .map_meta_equal = array_map_meta_equal, .map_alloc_check = array_map_alloc_check, .map_alloc = array_map_alloc, .map_free = array_map_free, -- cgit v1.2.3