From 81374aaa2693f8d3cd6cf3656a02ac8cf5c7ebea Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 28 Aug 2017 07:11:43 -0700 Subject: [PATCH] bpf: harden sockmap program attach to ensure correct map type When attaching a program to sockmap we need to check map type is correct. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 3 +++ tools/testing/selftests/bpf/sockmap_verdict_prog.c | 7 ++++++ tools/testing/selftests/bpf/test_maps.c | 27 ++++++++++++++++++---- 3 files changed, 33 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 266011c8..38bf4e4 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -794,6 +794,9 @@ int sock_map_attach_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type) struct bpf_stab *stab = container_of(map, struct bpf_stab, map); struct bpf_prog *orig; + if (unlikely(map->map_type != BPF_MAP_TYPE_SOCKMAP)) + return -EINVAL; + switch (type) { case BPF_SK_SKB_STREAM_PARSER: orig = xchg(&stab->bpf_parse, prog); diff --git a/tools/testing/selftests/bpf/sockmap_verdict_prog.c b/tools/testing/selftests/bpf/sockmap_verdict_prog.c index dada207..9b99bd1 100644 --- a/tools/testing/selftests/bpf/sockmap_verdict_prog.c +++ b/tools/testing/selftests/bpf/sockmap_verdict_prog.c @@ -26,6 +26,13 @@ struct bpf_map_def SEC("maps") sock_map_tx = { .max_entries = 20, }; +struct bpf_map_def SEC("maps") sock_map_break = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(int), + .value_size = sizeof(int), + .max_entries = 20, +}; + SEC("sk_skb2") int bpf_prog2(struct __sk_buff *skb) { diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c index 0a7f457..0c4b56d 100644 --- a/tools/testing/selftests/bpf/test_maps.c +++ b/tools/testing/selftests/bpf/test_maps.c @@ -463,12 +463,12 @@ static void test_devmap(int task, void *data) #define SOCKMAP_VERDICT_PROG "./sockmap_verdict_prog.o" static void test_sockmap(int task, void *data) { + int one = 1, map_fd_rx, map_fd_tx, map_fd_break, s, sc, rc; + struct bpf_map *bpf_map_rx, *bpf_map_tx, *bpf_map_break; int ports[] = {50200, 50201, 50202, 50204}; int err, i, fd, sfd[6] = {0xdeadbeef}; u8 buf[20] = {0x0, 0x5, 0x3, 0x2, 0x1, 0x0}; - int one = 1, map_fd_rx, map_fd_tx, s, sc, rc; int parse_prog, verdict_prog; - struct bpf_map *bpf_map_rx, *bpf_map_tx; struct sockaddr_in addr; struct bpf_object *obj; struct timeval to; @@ -609,17 +609,36 @@ static void test_sockmap(int task, void *data) goto out_sockmap; } + bpf_map_break = bpf_object__find_map_by_name(obj, "sock_map_break"); + if (IS_ERR(bpf_map_break)) { + printf("Failed to load map tx from verdict prog\n"); + goto out_sockmap; + } + + map_fd_break = bpf_map__fd(bpf_map_break); + if (map_fd_break < 0) { + printf("Failed to get map tx fd\n"); + goto out_sockmap; + } + + err = bpf_prog_attach(parse_prog, map_fd_break, + BPF_SK_SKB_STREAM_PARSER, 0); + if (!err) { + printf("Allowed attaching SK_SKB program to invalid map\n"); + goto out_sockmap; + } + err = bpf_prog_attach(parse_prog, map_fd_rx, BPF_SK_SKB_STREAM_PARSER, 0); if (err) { - printf("Failed bpf prog attach\n"); + printf("Failed stream parser bpf prog attach\n"); goto out_sockmap; } err = bpf_prog_attach(verdict_prog, map_fd_rx, BPF_SK_SKB_STREAM_VERDICT, 0); if (err) { - printf("Failed bpf prog attach\n"); + printf("Failed stream verdict bpf prog attach\n"); goto out_sockmap; } -- 2.7.4