From d056a788765e67773124f520159185bc89f5d1ad Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 15 Jun 2016 22:47:13 +0200 Subject: [PATCH] bpf, maps: extend map_fd_get_ptr arguments This patch extends map_fd_get_ptr() callback that is used by fd array maps, so that struct file pointer from the related map can be passed in. It's safe to remove map_update_elem() callback for the two maps since this is only allowed from syscall side, but not from eBPF programs for these two map types. Like in per-cpu map case, bpf_fd_array_map_update_elem() needs to be called directly here due to the extra argument. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/bpf.h | 12 +++++++++--- kernel/bpf/arraymap.c | 16 +++++++++------- kernel/bpf/syscall.c | 6 ++++++ 3 files changed, 24 insertions(+), 10 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 29b5a1ae22cb..d7b43e73fe87 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -29,8 +29,9 @@ struct bpf_map_ops { int (*map_delete_elem)(struct bpf_map *map, void *key); /* funcs called by prog_array and perf_event_array map */ - void *(*map_fd_get_ptr) (struct bpf_map *map, int fd); - void (*map_fd_put_ptr) (void *ptr); + void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file, + int fd); + void (*map_fd_put_ptr)(void *ptr); }; struct bpf_map { @@ -169,7 +170,7 @@ struct bpf_array { u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); -void bpf_fd_array_map_clear(struct bpf_map *map); + bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); const struct bpf_func_proto *bpf_get_trace_printk_proto(void); @@ -207,8 +208,13 @@ int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, u64 flags); int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, u64 flags); + int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value); +int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file, + void *key, void *value, u64 map_flags); +void bpf_fd_array_map_clear(struct bpf_map *map); + /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and * forced to use 'long' read/writes to try to atomically copy long counters. * Best-effort only. No barriers here, since it _will_ race with concurrent diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 76d5a794e426..bfedcbdb4d84 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -328,8 +328,8 @@ static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key) } /* only called from syscall */ -static int fd_array_map_update_elem(struct bpf_map *map, void *key, - void *value, u64 map_flags) +int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file, + void *key, void *value, u64 map_flags) { struct bpf_array *array = container_of(map, struct bpf_array, map); void *new_ptr, *old_ptr; @@ -342,7 +342,7 @@ static int fd_array_map_update_elem(struct bpf_map *map, void *key, return -E2BIG; ufd = *(u32 *)value; - new_ptr = map->ops->map_fd_get_ptr(map, ufd); + new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd); if (IS_ERR(new_ptr)) return PTR_ERR(new_ptr); @@ -371,10 +371,12 @@ static int fd_array_map_delete_elem(struct bpf_map *map, void *key) } } -static void *prog_fd_array_get_ptr(struct bpf_map *map, int fd) +static void *prog_fd_array_get_ptr(struct bpf_map *map, + struct file *map_file, int fd) { struct bpf_array *array = container_of(map, struct bpf_array, map); struct bpf_prog *prog = bpf_prog_get(fd); + if (IS_ERR(prog)) return prog; @@ -382,6 +384,7 @@ static void *prog_fd_array_get_ptr(struct bpf_map *map, int fd) bpf_prog_put(prog); return ERR_PTR(-EINVAL); } + return prog; } @@ -407,7 +410,6 @@ static const struct bpf_map_ops prog_array_ops = { .map_free = fd_array_map_free, .map_get_next_key = array_map_get_next_key, .map_lookup_elem = fd_array_map_lookup_elem, - .map_update_elem = fd_array_map_update_elem, .map_delete_elem = fd_array_map_delete_elem, .map_fd_get_ptr = prog_fd_array_get_ptr, .map_fd_put_ptr = prog_fd_array_put_ptr, @@ -431,7 +433,8 @@ static void perf_event_array_map_free(struct bpf_map *map) fd_array_map_free(map); } -static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd) +static void *perf_event_fd_array_get_ptr(struct bpf_map *map, + struct file *map_file, int fd) { struct perf_event *event; const struct perf_event_attr *attr; @@ -474,7 +477,6 @@ static const struct bpf_map_ops perf_event_array_ops = { .map_free = perf_event_array_map_free, .map_get_next_key = array_map_get_next_key, .map_lookup_elem = fd_array_map_lookup_elem, - .map_update_elem = fd_array_map_update_elem, .map_delete_elem = fd_array_map_delete_elem, .map_fd_get_ptr = perf_event_fd_array_get_ptr, .map_fd_put_ptr = perf_event_fd_array_put_ptr, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index fc3adcd064b1..c23a4e9311b3 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -392,6 +392,12 @@ static int map_update_elem(union bpf_attr *attr) err = bpf_percpu_hash_update(map, key, value, attr->flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_update(map, key, value, attr->flags); + } else if (map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || + map->map_type == BPF_MAP_TYPE_PROG_ARRAY) { + rcu_read_lock(); + err = bpf_fd_array_map_update_elem(map, f.file, key, value, + attr->flags); + rcu_read_unlock(); } else { rcu_read_lock(); err = map->ops->map_update_elem(map, key, value, attr->flags); -- 2.20.1