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    Subject[PATCH 5.9 350/757] selftests/bpf: Fix endianness issues in sk_lookup/ctx_narrow_access
    Date
    From: Ilya Leoshkevich <iii@linux.ibm.com>

    [ Upstream commit 6458bde368cee77e798d05cccd2316db4d748c41 ]

    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@linux.ibm.com>
    Signed-off-by: Alexei Starovoitov <ast@kernel.org>
    Link: https://lore.kernel.org/bpf/20200929201814.44360-1-iii@linux.ibm.com
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    .../selftests/bpf/progs/test_sk_lookup.c | 216 ++++++++----------
    1 file changed, 101 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 bbf8296f4d663..1032b292af5b7 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 +380,146 @@ 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;
    }

    --
    2.25.1


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