Commit 1a5df073 authored Feb 27, 2019 by Peng Sun Committed by Greg Kroah-Hartman Dec 05, 2019

bpf: drop refcount if bpf_map_new_fd() fails in map_create()



[ Upstream commit 352d20d611414715353ee65fc206ee57ab1a6984 ]

In bpf/syscall.c, map_create() first set map->usercnt to 1, a file
descriptor is supposed to return to userspace. When bpf_map_new_fd()
fails, drop the refcount.

Fixes: bd5f5f4e ("bpf: Add BPF_MAP_GET_FD_BY_ID")
Signed-off-by: Peng Sun <sironhide0null@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 9c458dd1

kernel/bpf/syscall.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -559,12 +559,12 @@ static int map_create(union bpf_attr *attr)
		err = bpf_map_new_fd(map, f_flags);
		if (err < 0) {
		/* failed to allocate fd.
		* bpf_map_put() is needed because the above
		* bpf_map_put_with_uref() is needed because the above
		* bpf_map_alloc_id() has published the map
		* to the userspace and the userspace may
		* have refcnt-ed it through BPF_MAP_GET_FD_BY_ID.
		*/
		bpf_map_put(map);
		bpf_map_put_with_uref(map);
		return err;
		}