Commit 1ea0f912 authored May 27, 2020 by Anton Protopopov Committed by Alexei Starovoitov Jun 01, 2020

bpf: Fix map permissions check

The map_lookup_and_delete_elem() function should check for both FMODE_CAN_WRITE
and FMODE_CAN_READ permissions because it returns a map element to user space.

Fixes: bd513cd0 ("bpf: add MAP_LOOKUP_AND_DELETE_ELEM syscall")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200527185700.14658-5-a.s.protopopov@gmail.com

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent efbc3b8f

kernel/bpf/syscall.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1472,7 +1472,8 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr)
		map = __bpf_map_get(f);
		if (IS_ERR(map))
		return PTR_ERR(map);
		if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
		if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ) \|\|
		!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
		err = -EPERM;
		goto err_put;
		}