diff mbox series

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

Message ID 20200508123139.247890347@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman May 8, 2020, 12:33 p.m. UTC 
From: Daniel Borkmann <daniel@iogearbox.net>

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

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

Patch

--- 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;
 }