From 6d67942dd0ebc3dddc86edf9208169d064a9b3d7 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 19 Nov 2016 01:45:03 +0100 Subject: [PATCH] bpf: add __must_check attributes to refcount manipulating helpers Helpers like bpf_prog_add(), bpf_prog_inc(), bpf_map_inc() can fail with an error, so make sure the caller properly checks their return value and not just ignores it, which could worst-case lead to use after free. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/bpf.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 01c1487277b2..69d0a7f12a3b 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -233,14 +233,14 @@ void bpf_register_map_type(struct bpf_map_type_list *tl); struct bpf_prog *bpf_prog_get(u32 ufd); struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type); -struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i); +struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i); void bpf_prog_sub(struct bpf_prog *prog, int i); -struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog); +struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog); void bpf_prog_put(struct bpf_prog *prog); struct bpf_map *bpf_map_get_with_uref(u32 ufd); struct bpf_map *__bpf_map_get(struct fd f); -struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref); +struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref); void bpf_map_put_with_uref(struct bpf_map *map); void bpf_map_put(struct bpf_map *map); int bpf_map_precharge_memlock(u32 pages); @@ -299,7 +299,8 @@ static inline struct bpf_prog *bpf_prog_get_type(u32 ufd, { return ERR_PTR(-EOPNOTSUPP); } -static inline struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) +static inline struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, + int i) { return ERR_PTR(-EOPNOTSUPP); } @@ -311,7 +312,8 @@ static inline void bpf_prog_sub(struct bpf_prog *prog, int i) static inline void bpf_prog_put(struct bpf_prog *prog) { } -static inline struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) + +static inline struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog) { return ERR_PTR(-EOPNOTSUPP); } -- 2.20.1