bpf: Prevent pointer mismatch in bpf_timer_init.

bpf_timer_init() arguments are:
1. pointer to a timer (which is embedded in map element).
2. pointer to a map.
Make sure that pointer to a timer actually belongs to that map.

Use map_uid (which is unique id of inner map) to reject:
inner_map1 = bpf_map_lookup_elem(outer_map, key1)
inner_map2 = bpf_map_lookup_elem(outer_map, key2)
if (inner_map1 && inner_map2) {
    timer = bpf_map_lookup_elem(inner_map1);
    if (timer)
        // mismatch would have been allowed
        bpf_timer_init(timer, inner_map2);
}

Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Acked-by: Toke Høiland-Jørgensen <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

0 files changed, 0 insertions, 0 deletions