[PATCH net-next 2/4] bpf: align and clean bpf_{map,prog}_get helpers

[Daniel Borkmann]

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 
---
 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 e3a51b7..0ae6f77 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 2b89ef0..3fff82c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -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 != _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(>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 != _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(>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 1d6b97b..735999a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1988,8 +1988,7 @@ 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);
-- 
1.9.3

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[PATCH net-next 2/4] bpf: align and clean bpf_{map,prog}_get helpers

[Daniel Borkmann]

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 
---
 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 e3a51b7..0ae6f77 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 2b89ef0..3fff82c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -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 != _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(>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 != _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(>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 1d6b97b..735999a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1988,8 +1988,7 @@ 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);
-- 
1.9.3

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