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Commit 81374aaa authored by John Fastabend's avatar John Fastabend Committed by David S. Miller
Browse files

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: 174a79ff ("bpf: sockmap with sk redirect support")
Signed-off-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ed85054d

kernel/bpf/sockmap.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

tools/testing/selftests/bpf/sockmap_verdict_prog.c

+7 −0
Original line number Diff line number Diff line
@@ -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)

{

tools/testing/selftests/bpf/test_maps.c

+23 −4
Original line number Diff line number Diff line
@@ -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;

	}