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Commit d056a788 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 61d1b6a4

include/linux/bpf.h

+9 −3
Original line number Diff line number Diff line
@@ -29,7 +29,8 @@ 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_get_ptr)(struct bpf_map *map, struct file *map_file,

				int fd);

	void (*map_fd_put_ptr)(void *ptr);

};
@@ -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

kernel/bpf/arraymap.c

+9 −7
Original line number Diff line number Diff line
@@ -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,

kernel/bpf/syscall.c

+6 −0
Original line number Diff line number Diff line
@@ -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);