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 <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 7 deletions

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);