From 3ac1a467e37683f602221e243fa3c59b0de81165 Mon Sep 17 00:00:00 2001 From: Junyoung Jang Date: Mon, 27 Apr 2026 02:25:05 +0900 Subject: [PATCH] bpf: Fix off-by-one boundary validation in arena direct-value access BPF_MAP_TYPE_ARENA accepts BPF_PSEUDO_MAP_VALUE offsets at exactly the end of the arena mapping (off == arena_size). The boundary check in arena_map_direct_value_addr() uses `>` instead of `>=`, which incorrectly allows a one-past-end pointer to be accepted. Change the condition to `>=` to correctly reject offsets that fall outside the valid arena user_vm range. Fixes: 317460317a02 ("bpf: Introduce bpf_arena.") Signed-off-by: Junyoung Jang Reviewed-by: Emil Tsalapatis Link: https://lore.kernel.org/r/20260426172505.1947915-1-graypanda.inzag@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/arena.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index 802656c6fd3c..49a8f7b1beef 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -511,7 +511,7 @@ static int arena_map_direct_value_addr(const struct bpf_map *map, u64 *imm, u32 { struct bpf_arena *arena = container_of(map, struct bpf_arena, map); - if ((u64)off > arena->user_vm_end - arena->user_vm_start) + if ((u64)off >= arena->user_vm_end - arena->user_vm_start) return -ERANGE; *imm = (unsigned long)arena->user_vm_start; return 0;