[PATCH 4.4 211/312] bpf: fix map not being uncharged during map creation failure

[Greg Kroah-Hartman]

From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

commit 20b2b24f91f70e7d3f0918c077546cb21bd73a87 upstream.

In map_create(), we first find and create the map, then once that
suceeded, we charge it to the user's RLIMIT_MEMLOCK, and then fetch
a new anon fd through anon_inode_getfd(). The problem is, once the
latter fails f.e. due to RLIMIT_NOFILE limit, then we only destruct
the map via map->ops->map_free(), but without uncharging the previously
locked memory first. That means that the user_struct allocation is
leaked as well as the accounted RLIMIT_MEMLOCK memory not released.
Make the label names in the fix consistent with bpf_prog_load().

Fixes: aaac3ba95e4c ("bpf: charge user for creation of BPF maps and programs")
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/bpf/syscall.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -152,7 +152,7 @@ static int map_create(union bpf_attr *at
 
 	err = bpf_map_charge_memlock(map);
 	if (err)
-		goto free_map;
+		goto free_map_nouncharge;
 
 	err = bpf_map_new_fd(map);
 	if (err < 0)
@@ -162,6 +162,8 @@ static int map_create(union bpf_attr *at
 	return err;
 
 free_map:
+	bpf_map_uncharge_memlock(map);
+free_map_nouncharge:
 	map->ops->map_free(map);
 	return err;
 }