From: Anton Protopopov a.s.protopopov@gmail.com
[ Upstream commit 1ea0f9120c8ce105ca181b070561df5cbd6bc049 ]
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: bd513cd08f10 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/syscall.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 4e6dee19a668..5e52765161f9 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1468,7 +1468,8 @@ 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; }