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

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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: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2015-10-29 14:58:07 +01:00 committed by David S. Miller
parent aa79781b65
commit c210129760
3 changed files with 25 additions and 21 deletions
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2
include/linux/bpf.h
View File

@ -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;

41
kernel/bpf/syscall.c
View File

@ -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);

3
kernel/bpf/verifier.c
View File

@ -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);