On Wed, Sep 9, 2020 at 6:59 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> This test makes a lot of narrow load checks while assuming little
> endian architecture, and therefore fails on s390.
>
> Fix by introducing LSB and LSW macros and using them to perform narrow
> loads.
>
> Fixes: 0ab5539f8584 ("selftests/bpf: Tests for BPF_SK_LOOKUP attach point")
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
Jakub,
Can you please help review this to make sure no error accidentally slipped in?
> .../selftests/bpf/progs/test_sk_lookup.c | 264 ++++++++++--------
> 1 file changed, 149 insertions(+), 115 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/test_sk_lookup.c b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
> index bbf8296f4d66..94e6d370967b 100644
> --- a/tools/testing/selftests/bpf/progs/test_sk_lookup.c
> +++ b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
> @@ -19,6 +19,17 @@
> #define IP6(aaaa, bbbb, cccc, dddd) \
> { bpf_htonl(aaaa), bpf_htonl(bbbb), bpf_htonl(cccc), bpf_htonl(dddd) }
>
> +/* Macros for least-significant byte and word accesses. */
> +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
> +#define LSE_INDEX(index, size) (index)
> +#else
> +#define LSE_INDEX(index, size) ((size) - (index) - 1)
> +#endif
> +#define LSB(value, index) \
> + (((__u8 *)&(value))[LSE_INDEX((index), sizeof(value))])
> +#define LSW(value, index) \
> + (((__u16 *)&(value))[LSE_INDEX((index), sizeof(value) / 2)])
> +
> #define MAX_SOCKS 32
>
> struct {
> @@ -369,171 +380,194 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)
> {
> struct bpf_sock *sk;
> int err, family;
> - __u16 *half;
> - __u8 *byte;
> bool v4;
>
> v4 = (ctx->family == AF_INET);
>
> /* Narrow loads from family field */
> - byte = (__u8 *)&ctx->family;
> - half = (__u16 *)&ctx->family;
> - if (byte[0] != (v4 ? AF_INET : AF_INET6) ||
> - byte[1] != 0 || byte[2] != 0 || byte[3] != 0)
> + if (LSB(ctx->family, 0) != (v4 ? AF_INET : AF_INET6) ||
> + LSB(ctx->family, 1) != 0 || LSB(ctx->family, 2) != 0 ||
> + LSB(ctx->family, 3) != 0)
> return SK_DROP;
> - if (half[0] != (v4 ? AF_INET : AF_INET6))
> + if (LSW(ctx->family, 0) != (v4 ? AF_INET : AF_INET6))
> return SK_DROP;
>
> - byte = (__u8 *)&ctx->protocol;
> - if (byte[0] != IPPROTO_TCP ||
> - byte[1] != 0 || byte[2] != 0 || byte[3] != 0)
> + /* Narrow loads from protocol field */
> + if (LSB(ctx->protocol, 0) != IPPROTO_TCP ||
> + LSB(ctx->protocol, 1) != 0 || LSB(ctx->protocol, 2) != 0 ||
> + LSB(ctx->protocol, 3) != 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->protocol;
> - if (half[0] != IPPROTO_TCP)
> + if (LSW(ctx->protocol, 0) != IPPROTO_TCP)
> return SK_DROP;
>
> /* Narrow loads from remote_port field. Expect non-0 value. */
> - byte = (__u8 *)&ctx->remote_port;
> - if (byte[0] == 0 && byte[1] == 0 && byte[2] == 0 && byte[3] == 0)
> + if (LSB(ctx->remote_port, 0) == 0 && LSB(ctx->remote_port, 1) == 0 &&
> + LSB(ctx->remote_port, 2) == 0 && LSB(ctx->remote_port, 3) == 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->remote_port;
> - if (half[0] == 0)
> + if (LSW(ctx->remote_port, 0) == 0)
> return SK_DROP;
>
> /* Narrow loads from local_port field. Expect DST_PORT. */
> - byte = (__u8 *)&ctx->local_port;
> - if (byte[0] != ((DST_PORT >> 0) & 0xff) ||
> - byte[1] != ((DST_PORT >> 8) & 0xff) ||
> - byte[2] != 0 || byte[3] != 0)
> + if (LSB(ctx->local_port, 0) != ((DST_PORT >> 0) & 0xff) ||
> + LSB(ctx->local_port, 1) != ((DST_PORT >> 8) & 0xff) ||
> + LSB(ctx->local_port, 2) != 0 || LSB(ctx->local_port, 3) != 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->local_port;
> - if (half[0] != DST_PORT)
> + if (LSW(ctx->local_port, 0) != DST_PORT)
> return SK_DROP;
>
> /* Narrow loads from IPv4 fields */
> if (v4) {
> /* Expect non-0.0.0.0 in remote_ip4 */
> - byte = (__u8 *)&ctx->remote_ip4;
> - if (byte[0] == 0 && byte[1] == 0 &&
> - byte[2] == 0 && byte[3] == 0)
> + if (LSB(ctx->remote_ip4, 0) == 0 &&
> + LSB(ctx->remote_ip4, 1) == 0 &&
> + LSB(ctx->remote_ip4, 2) == 0 &&
> + LSB(ctx->remote_ip4, 3) == 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->remote_ip4;
> - if (half[0] == 0 && half[1] == 0)
> + if (LSW(ctx->remote_ip4, 0) == 0 &&
> + LSW(ctx->remote_ip4, 1) == 0)
> return SK_DROP;
>
> /* Expect DST_IP4 in local_ip4 */
> - byte = (__u8 *)&ctx->local_ip4;
> - if (byte[0] != ((DST_IP4 >> 0) & 0xff) ||
> - byte[1] != ((DST_IP4 >> 8) & 0xff) ||
> - byte[2] != ((DST_IP4 >> 16) & 0xff) ||
> - byte[3] != ((DST_IP4 >> 24) & 0xff))
> + if (LSB(ctx->local_ip4, 0) != ((DST_IP4 >> 0) & 0xff) ||
> + LSB(ctx->local_ip4, 1) != ((DST_IP4 >> 8) & 0xff) ||
> + LSB(ctx->local_ip4, 2) != ((DST_IP4 >> 16) & 0xff) ||
> + LSB(ctx->local_ip4, 3) != ((DST_IP4 >> 24) & 0xff))
> return SK_DROP;
> - half = (__u16 *)&ctx->local_ip4;
> - if (half[0] != ((DST_IP4 >> 0) & 0xffff) ||
> - half[1] != ((DST_IP4 >> 16) & 0xffff))
> + if (LSW(ctx->local_ip4, 0) != ((DST_IP4 >> 0) & 0xffff) ||
> + LSW(ctx->local_ip4, 1) != ((DST_IP4 >> 16) & 0xffff))
> return SK_DROP;
> } else {
> /* Expect 0.0.0.0 IPs when family != AF_INET */
> - byte = (__u8 *)&ctx->remote_ip4;
> - if (byte[0] != 0 || byte[1] != 0 &&
> - byte[2] != 0 || byte[3] != 0)
> + if (LSB(ctx->remote_ip4, 0) != 0 ||
> + LSB(ctx->remote_ip4, 1) != 0 ||
> + LSB(ctx->remote_ip4, 2) != 0 ||
> + LSB(ctx->remote_ip4, 3) != 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->remote_ip4;
> - if (half[0] != 0 || half[1] != 0)
> + if (LSW(ctx->remote_ip4, 0) != 0 ||
> + LSW(ctx->remote_ip4, 1) != 0)
> return SK_DROP;
>
> - byte = (__u8 *)&ctx->local_ip4;
> - if (byte[0] != 0 || byte[1] != 0 &&
> - byte[2] != 0 || byte[3] != 0)
> + if (LSB(ctx->local_ip4, 0) != 0 ||
> + LSB(ctx->local_ip4, 1) != 0 ||
> + LSB(ctx->local_ip4, 2) != 0 || LSB(ctx->local_ip4, 3) != 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->local_ip4;
> - if (half[0] != 0 || half[1] != 0)
> + if (LSW(ctx->local_ip4, 0) != 0 || LSW(ctx->local_ip4, 1) != 0)
> return SK_DROP;
> }
>
> /* Narrow loads from IPv6 fields */
> if (!v4) {
> - /* Expenct non-:: IP in remote_ip6 */
> - byte = (__u8 *)&ctx->remote_ip6;
> - if (byte[0] == 0 && byte[1] == 0 &&
> - byte[2] == 0 && byte[3] == 0 &&
> - byte[4] == 0 && byte[5] == 0 &&
> - byte[6] == 0 && byte[7] == 0 &&
> - byte[8] == 0 && byte[9] == 0 &&
> - byte[10] == 0 && byte[11] == 0 &&
> - byte[12] == 0 && byte[13] == 0 &&
> - byte[14] == 0 && byte[15] == 0)
> + /* Expect non-:: IP in remote_ip6 */
> + if (LSB(ctx->remote_ip6[0], 0) == 0 &&
> + LSB(ctx->remote_ip6[0], 1) == 0 &&
> + LSB(ctx->remote_ip6[0], 2) == 0 &&
> + LSB(ctx->remote_ip6[0], 3) == 0 &&
> + LSB(ctx->remote_ip6[1], 0) == 0 &&
> + LSB(ctx->remote_ip6[1], 1) == 0 &&
> + LSB(ctx->remote_ip6[1], 2) == 0 &&
> + LSB(ctx->remote_ip6[1], 3) == 0 &&
> + LSB(ctx->remote_ip6[2], 0) == 0 &&
> + LSB(ctx->remote_ip6[2], 1) == 0 &&
> + LSB(ctx->remote_ip6[2], 2) == 0 &&
> + LSB(ctx->remote_ip6[2], 3) == 0 &&
> + LSB(ctx->remote_ip6[3], 0) == 0 &&
> + LSB(ctx->remote_ip6[3], 1) == 0 &&
> + LSB(ctx->remote_ip6[3], 2) == 0 &&
> + LSB(ctx->remote_ip6[3], 3) == 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->remote_ip6;
> - if (half[0] == 0 && half[1] == 0 &&
> - half[2] == 0 && half[3] == 0 &&
> - half[4] == 0 && half[5] == 0 &&
> - half[6] == 0 && half[7] == 0)
> + if (LSW(ctx->remote_ip6[0], 0) == 0 &&
> + LSW(ctx->remote_ip6[0], 1) == 0 &&
> + LSW(ctx->remote_ip6[1], 0) == 0 &&
> + LSW(ctx->remote_ip6[1], 1) == 0 &&
> + LSW(ctx->remote_ip6[2], 0) == 0 &&
> + LSW(ctx->remote_ip6[2], 1) == 0 &&
> + LSW(ctx->remote_ip6[3], 0) == 0 &&
> + LSW(ctx->remote_ip6[3], 1) == 0)
> return SK_DROP;
> -
> /* Expect DST_IP6 in local_ip6 */
> - byte = (__u8 *)&ctx->local_ip6;
> - if (byte[0] != ((DST_IP6[0] >> 0) & 0xff) ||
> - byte[1] != ((DST_IP6[0] >> 8) & 0xff) ||
> - byte[2] != ((DST_IP6[0] >> 16) & 0xff) ||
> - byte[3] != ((DST_IP6[0] >> 24) & 0xff) ||
> - byte[4] != ((DST_IP6[1] >> 0) & 0xff) ||
> - byte[5] != ((DST_IP6[1] >> 8) & 0xff) ||
> - byte[6] != ((DST_IP6[1] >> 16) & 0xff) ||
> - byte[7] != ((DST_IP6[1] >> 24) & 0xff) ||
> - byte[8] != ((DST_IP6[2] >> 0) & 0xff) ||
> - byte[9] != ((DST_IP6[2] >> 8) & 0xff) ||
> - byte[10] != ((DST_IP6[2] >> 16) & 0xff) ||
> - byte[11] != ((DST_IP6[2] >> 24) & 0xff) ||
> - byte[12] != ((DST_IP6[3] >> 0) & 0xff) ||
> - byte[13] != ((DST_IP6[3] >> 8) & 0xff) ||
> - byte[14] != ((DST_IP6[3] >> 16) & 0xff) ||
> - byte[15] != ((DST_IP6[3] >> 24) & 0xff))
> + if (LSB(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xff) ||
> + LSB(ctx->local_ip6[0], 1) != ((DST_IP6[0] >> 8) & 0xff) ||
> + LSB(ctx->local_ip6[0], 2) != ((DST_IP6[0] >> 16) & 0xff) ||
> + LSB(ctx->local_ip6[0], 3) != ((DST_IP6[0] >> 24) & 0xff) ||
> + LSB(ctx->local_ip6[1], 0) != ((DST_IP6[1] >> 0) & 0xff) ||
> + LSB(ctx->local_ip6[1], 1) != ((DST_IP6[1] >> 8) & 0xff) ||
> + LSB(ctx->local_ip6[1], 2) != ((DST_IP6[1] >> 16) & 0xff) ||
> + LSB(ctx->local_ip6[1], 3) != ((DST_IP6[1] >> 24) & 0xff) ||
> + LSB(ctx->local_ip6[2], 0) != ((DST_IP6[2] >> 0) & 0xff) ||
> + LSB(ctx->local_ip6[2], 1) != ((DST_IP6[2] >> 8) & 0xff) ||
> + LSB(ctx->local_ip6[2], 2) != ((DST_IP6[2] >> 16) & 0xff) ||
> + LSB(ctx->local_ip6[2], 3) != ((DST_IP6[2] >> 24) & 0xff) ||
> + LSB(ctx->local_ip6[3], 0) != ((DST_IP6[3] >> 0) & 0xff) ||
> + LSB(ctx->local_ip6[3], 1) != ((DST_IP6[3] >> 8) & 0xff) ||
> + LSB(ctx->local_ip6[3], 2) != ((DST_IP6[3] >> 16) & 0xff) ||
> + LSB(ctx->local_ip6[3], 3) != ((DST_IP6[3] >> 24) & 0xff))
> return SK_DROP;
> - half = (__u16 *)&ctx->local_ip6;
> - if (half[0] != ((DST_IP6[0] >> 0) & 0xffff) ||
> - half[1] != ((DST_IP6[0] >> 16) & 0xffff) ||
> - half[2] != ((DST_IP6[1] >> 0) & 0xffff) ||
> - half[3] != ((DST_IP6[1] >> 16) & 0xffff) ||
> - half[4] != ((DST_IP6[2] >> 0) & 0xffff) ||
> - half[5] != ((DST_IP6[2] >> 16) & 0xffff) ||
> - half[6] != ((DST_IP6[3] >> 0) & 0xffff) ||
> - half[7] != ((DST_IP6[3] >> 16) & 0xffff))
> + if (LSW(ctx->local_ip6[0], 0) != ((DST_IP6[0] >> 0) & 0xffff) ||
> + LSW(ctx->local_ip6[0], 1) !=
> + ((DST_IP6[0] >> 16) & 0xffff) ||
> + LSW(ctx->local_ip6[1], 0) != ((DST_IP6[1] >> 0) & 0xffff) ||
> + LSW(ctx->local_ip6[1], 1) !=
> + ((DST_IP6[1] >> 16) & 0xffff) ||
> + LSW(ctx->local_ip6[2], 0) != ((DST_IP6[2] >> 0) & 0xffff) ||
> + LSW(ctx->local_ip6[2], 1) !=
> + ((DST_IP6[2] >> 16) & 0xffff) ||
> + LSW(ctx->local_ip6[3], 0) != ((DST_IP6[3] >> 0) & 0xffff) ||
> + LSW(ctx->local_ip6[3], 1) != ((DST_IP6[3] >> 16) & 0xffff))
> return SK_DROP;
> } else {
> /* Expect :: IPs when family != AF_INET6 */
> - byte = (__u8 *)&ctx->remote_ip6;
> - if (byte[0] != 0 || byte[1] != 0 ||
> - byte[2] != 0 || byte[3] != 0 ||
> - byte[4] != 0 || byte[5] != 0 ||
> - byte[6] != 0 || byte[7] != 0 ||
> - byte[8] != 0 || byte[9] != 0 ||
> - byte[10] != 0 || byte[11] != 0 ||
> - byte[12] != 0 || byte[13] != 0 ||
> - byte[14] != 0 || byte[15] != 0)
> + if (LSB(ctx->remote_ip6[0], 0) != 0 ||
> + LSB(ctx->remote_ip6[0], 1) != 0 ||
> + LSB(ctx->remote_ip6[0], 2) != 0 ||
> + LSB(ctx->remote_ip6[0], 3) != 0 ||
> + LSB(ctx->remote_ip6[1], 0) != 0 ||
> + LSB(ctx->remote_ip6[1], 1) != 0 ||
> + LSB(ctx->remote_ip6[1], 2) != 0 ||
> + LSB(ctx->remote_ip6[1], 3) != 0 ||
> + LSB(ctx->remote_ip6[2], 0) != 0 ||
> + LSB(ctx->remote_ip6[2], 1) != 0 ||
> + LSB(ctx->remote_ip6[2], 2) != 0 ||
> + LSB(ctx->remote_ip6[2], 3) != 0 ||
> + LSB(ctx->remote_ip6[3], 0) != 0 ||
> + LSB(ctx->remote_ip6[3], 1) != 0 ||
> + LSB(ctx->remote_ip6[3], 2) != 0 ||
> + LSB(ctx->remote_ip6[3], 3) != 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->remote_ip6;
> - if (half[0] != 0 || half[1] != 0 ||
> - half[2] != 0 || half[3] != 0 ||
> - half[4] != 0 || half[5] != 0 ||
> - half[6] != 0 || half[7] != 0)
> + if (LSW(ctx->remote_ip6[0], 0) != 0 ||
> + LSW(ctx->remote_ip6[0], 1) != 0 ||
> + LSW(ctx->remote_ip6[1], 0) != 0 ||
> + LSW(ctx->remote_ip6[1], 1) != 0 ||
> + LSW(ctx->remote_ip6[2], 0) != 0 ||
> + LSW(ctx->remote_ip6[2], 1) != 0 ||
> + LSW(ctx->remote_ip6[3], 0) != 0 ||
> + LSW(ctx->remote_ip6[3], 1) != 0)
> return SK_DROP;
>
> - byte = (__u8 *)&ctx->local_ip6;
> - if (byte[0] != 0 || byte[1] != 0 ||
> - byte[2] != 0 || byte[3] != 0 ||
> - byte[4] != 0 || byte[5] != 0 ||
> - byte[6] != 0 || byte[7] != 0 ||
> - byte[8] != 0 || byte[9] != 0 ||
> - byte[10] != 0 || byte[11] != 0 ||
> - byte[12] != 0 || byte[13] != 0 ||
> - byte[14] != 0 || byte[15] != 0)
> + if (LSB(ctx->local_ip6[0], 0) != 0 ||
> + LSB(ctx->local_ip6[0], 1) != 0 ||
> + LSB(ctx->local_ip6[0], 2) != 0 ||
> + LSB(ctx->local_ip6[0], 3) != 0 ||
> + LSB(ctx->local_ip6[1], 0) != 0 ||
> + LSB(ctx->local_ip6[1], 1) != 0 ||
> + LSB(ctx->local_ip6[1], 2) != 0 ||
> + LSB(ctx->local_ip6[1], 3) != 0 ||
> + LSB(ctx->local_ip6[2], 0) != 0 ||
> + LSB(ctx->local_ip6[2], 1) != 0 ||
> + LSB(ctx->local_ip6[2], 2) != 0 ||
> + LSB(ctx->local_ip6[2], 3) != 0 ||
> + LSB(ctx->local_ip6[3], 0) != 0 ||
> + LSB(ctx->local_ip6[3], 1) != 0 ||
> + LSB(ctx->local_ip6[3], 2) != 0 ||
> + LSB(ctx->local_ip6[3], 3) != 0)
> return SK_DROP;
> - half = (__u16 *)&ctx->local_ip6;
> - if (half[0] != 0 || half[1] != 0 ||
> - half[2] != 0 || half[3] != 0 ||
> - half[4] != 0 || half[5] != 0 ||
> - half[6] != 0 || half[7] != 0)
> + if (LSW(ctx->remote_ip6[0], 0) != 0 ||
> + LSW(ctx->remote_ip6[0], 1) != 0 ||
> + LSW(ctx->remote_ip6[1], 0) != 0 ||
> + LSW(ctx->remote_ip6[1], 1) != 0 ||
> + LSW(ctx->remote_ip6[2], 0) != 0 ||
> + LSW(ctx->remote_ip6[2], 1) != 0 ||
> + LSW(ctx->remote_ip6[3], 0) != 0 ||
> + LSW(ctx->remote_ip6[3], 1) != 0)
> return SK_DROP;
> }
>
> --
> 2.25.4
>
