diff options
author | Kees Cook | 2021-09-28 16:09:46 -0700 |
---|---|---|
committer | Alexei Starovoitov | 2021-09-28 16:27:18 -0700 |
commit | 102acbacfd9a96d101abd96d1a7a5bf92b7c3e8e (patch) | |
tree | 18cfa723e40dbe24928faf0299bf0b90e8df9f43 /kernel/bpf | |
parent | 3d717fad5081b8e3bda76d86907fad95398cbde8 (diff) |
bpf: Replace callers of BPF_CAST_CALL with proper function typedef
In order to keep ahead of cases in the kernel where Control Flow
Integrity (CFI) may trip over function call casts, enabling
-Wcast-function-type is helpful. To that end, BPF_CAST_CALL causes
various warnings and is one of the last places in the kernel
triggering this warning.
For actual function calls, replace BPF_CAST_CALL() with a typedef, which
captures the same details about the given function pointers.
This change results in no object code difference.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://github.com/KSPP/linux/issues/20
Link: https://lore.kernel.org/lkml/CAEf4Bzb46=-J5Fxc3mMZ8JQPtK1uoE0q6+g6WPz53Cvx=CBEhw@mail.gmail.com
Link: https://lore.kernel.org/bpf/20210928230946.4062144-3-keescook@chromium.org
Diffstat (limited to 'kernel/bpf')
-rw-r--r-- | kernel/bpf/arraymap.c | 7 | ||||
-rw-r--r-- | kernel/bpf/hashtab.c | 7 | ||||
-rw-r--r-- | kernel/bpf/helpers.c | 5 |
3 files changed, 8 insertions, 11 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index cebd4fb06d19..5e1ccfae916b 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -645,7 +645,7 @@ static const struct bpf_iter_seq_info iter_seq_info = { .seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info), }; -static int bpf_for_each_array_elem(struct bpf_map *map, void *callback_fn, +static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn, void *callback_ctx, u64 flags) { u32 i, key, num_elems = 0; @@ -668,9 +668,8 @@ static int bpf_for_each_array_elem(struct bpf_map *map, void *callback_fn, val = array->value + array->elem_size * i; num_elems++; key = i; - ret = BPF_CAST_CALL(callback_fn)((u64)(long)map, - (u64)(long)&key, (u64)(long)val, - (u64)(long)callback_ctx, 0); + ret = callback_fn((u64)(long)map, (u64)(long)&key, + (u64)(long)val, (u64)(long)callback_ctx, 0); /* return value: 0 - continue, 1 - stop and return */ if (ret) break; diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 3d8f9d6997d5..d29af9988f37 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -2049,7 +2049,7 @@ static const struct bpf_iter_seq_info iter_seq_info = { .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info), }; -static int bpf_for_each_hash_elem(struct bpf_map *map, void *callback_fn, +static int bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_fn, void *callback_ctx, u64 flags) { struct bpf_htab *htab = container_of(map, struct bpf_htab, map); @@ -2089,9 +2089,8 @@ static int bpf_for_each_hash_elem(struct bpf_map *map, void *callback_fn, val = elem->key + roundup_key_size; } num_elems++; - ret = BPF_CAST_CALL(callback_fn)((u64)(long)map, - (u64)(long)key, (u64)(long)val, - (u64)(long)callback_ctx, 0); + ret = callback_fn((u64)(long)map, (u64)(long)key, + (u64)(long)val, (u64)(long)callback_ctx, 0); /* return value: 0 - continue, 1 - stop and return */ if (ret) { rcu_read_unlock(); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 2c604ff8c7fb..1ffd469c217f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1056,7 +1056,7 @@ static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer) struct bpf_hrtimer *t = container_of(hrtimer, struct bpf_hrtimer, timer); struct bpf_map *map = t->map; void *value = t->value; - void *callback_fn; + bpf_callback_t callback_fn; void *key; u32 idx; @@ -1081,8 +1081,7 @@ static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer) key = value - round_up(map->key_size, 8); } - BPF_CAST_CALL(callback_fn)((u64)(long)map, (u64)(long)key, - (u64)(long)value, 0, 0); + callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0); /* The verifier checked that return value is zero. */ this_cpu_write(hrtimer_running, NULL); |