Commit c2101297 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

bpf: align and clean bpf_{map,prog}_get helpers 



Add a bpf_map_get() function that we're going to use later on and
align/clean the remaining helpers a bit so that we have them a bit
more consistent:

  - __bpf_map_get() and __bpf_prog_get() that both work on the fd
    struct, check whether the descriptor is eBPF and return the
    pointer to the map/prog stored in the private data.

    Also, we can return f.file->private_data directly, the function
    signature is enough of a documentation already.

  - bpf_map_get() and bpf_prog_get() that both work on u32 user fd,
    call their respective __bpf_map_get()/__bpf_prog_get() variants,
    and take a reference.

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 aa79781b

include/linux/bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ struct bpf_prog *bpf_prog_get(u32 ufd); 
void bpf_prog_put(struct bpf_prog *prog);

void bpf_prog_put_rcu(struct bpf_prog *prog);



struct bpf_map *bpf_map_get(struct fd f);

struct bpf_map *__bpf_map_get(struct fd f);

void bpf_map_put(struct bpf_map *map);



extern int sysctl_unprivileged_bpf_disabled;

kernel/bpf/syscall.c

+23 −18
Original line number Diff line number Diff line
@@ -162,19 +162,29 @@ free_map: 
/* if error is returned, fd is released.

 * On success caller should complete fd access with matching fdput()

 */

struct bpf_map *bpf_map_get(struct fd f)

struct bpf_map *__bpf_map_get(struct fd f)

{

	struct bpf_map *map;



	if (!f.file)

		return ERR_PTR(-EBADF);



	if (f.file->f_op != &bpf_map_fops) {

		fdput(f);

		return ERR_PTR(-EINVAL);

	}



	map = f.file->private_data;

	return f.file->private_data;

}



static struct bpf_map *bpf_map_get(u32 ufd)

{

	struct fd f = fdget(ufd);

	struct bpf_map *map;



	map = __bpf_map_get(f);

	if (IS_ERR(map))

		return map;



	atomic_inc(&map->refcnt);

	fdput(f);



	return map;

}
@@ -202,7 +212,7 @@ static int map_lookup_elem(union bpf_attr *attr) 
		return -EINVAL;



	f = fdget(ufd);

	map = bpf_map_get(f);

	map = __bpf_map_get(f);

	if (IS_ERR(map))

		return PTR_ERR(map);
@@ -261,7 +271,7 @@ static int map_update_elem(union bpf_attr *attr) 
		return -EINVAL;



	f = fdget(ufd);

	map = bpf_map_get(f);

	map = __bpf_map_get(f);

	if (IS_ERR(map))

		return PTR_ERR(map);
@@ -314,7 +324,7 @@ static int map_delete_elem(union bpf_attr *attr) 
		return -EINVAL;



	f = fdget(ufd);

	map = bpf_map_get(f);

	map = __bpf_map_get(f);

	if (IS_ERR(map))

		return PTR_ERR(map);
@@ -355,7 +365,7 @@ static int map_get_next_key(union bpf_attr *attr) 
		return -EINVAL;



	f = fdget(ufd);

	map = bpf_map_get(f);

	map = __bpf_map_get(f);

	if (IS_ERR(map))

		return PTR_ERR(map);
@@ -549,21 +559,16 @@ static int bpf_prog_new_fd(struct bpf_prog *prog) 
				O_RDWR | O_CLOEXEC);

}



static struct bpf_prog *get_prog(struct fd f)

static struct bpf_prog *__bpf_prog_get(struct fd f)

{

	struct bpf_prog *prog;



	if (!f.file)

		return ERR_PTR(-EBADF);



	if (f.file->f_op != &bpf_prog_fops) {

		fdput(f);

		return ERR_PTR(-EINVAL);

	}



	prog = f.file->private_data;



	return prog;

	return f.file->private_data;

}



/* called by sockets/tracing/seccomp before attaching program to an event
@@ -574,13 +579,13 @@ struct bpf_prog *bpf_prog_get(u32 ufd) 
	struct fd f = fdget(ufd);

	struct bpf_prog *prog;



	prog = get_prog(f);



	prog = __bpf_prog_get(f);

	if (IS_ERR(prog))

		return prog;



	atomic_inc(&prog->aux->refcnt);

	fdput(f);



	return prog;

}

EXPORT_SYMBOL_GPL(bpf_prog_get);

kernel/bpf/verifier.c

+1 −2
Original line number Diff line number Diff line
@@ -1989,8 +1989,7 @@ static int replace_map_fd_with_map_ptr(struct verifier_env *env) 
			}



			f = fdget(insn->imm);



			map = bpf_map_get(f);

			map = __bpf_map_get(f);

			if (IS_ERR(map)) {

				verbose("fd %d is not pointing to valid bpf_map\n",

					insn->imm);

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