bpf: fix map not being uncharged during map creation failure

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@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 228f962447a5..237f3d6a7ddc 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -194,7 +194,7 @@ static int map_create(union bpf_attr *attr)
 
         err = bpf_map_charge_memlock(map);
         if (err)
-                goto free_map;
+                goto free_map_nouncharge;
 
         err = bpf_map_new_fd(map);
         if (err < 0)
@@ -204,6 +204,8 @@ static int map_create(union bpf_attr *attr)
         return err;
 
 free_map:
+        bpf_map_uncharge_memlock(map);
+free_map_nouncharge:
         map->ops->map_free(map);
         return err;
 }