From c210129760a010b555372ef74f4e1a46d4eb8a22 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 29 Oct 2015 14:58:07 +0100 Subject: [PATCH] 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: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/bpf.h | 2 +- kernel/bpf/syscall.c | 41 +++++++++++++++++++++++------------------ kernel/bpf/verifier.c | 3 +-- 3 files changed, 25 insertions(+), 21 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 75718fa28260..0b5fb6acef64 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -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; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2b89ef0a9757..3fff82ca68fa 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -162,19 +162,29 @@ static int map_create(union bpf_attr *attr) /* 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); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b56cf51f8d42..fdc88c5a60e3 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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);