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selftests/bpf: Fix endianness issues in sk_lookup/ctx_narrow_access
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[ Upstream commit 6458bde ]

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: 0ab5539 ("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>
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@iii-i @gregkh
iii-i authored and gregkh committed Oct 29, 2020
1 parent 9230bc3 commit c752772
Showing 1 changed file with 101 additions and 115 deletions.
216 changes: 101 additions & 115 deletions tools/testing/selftests/bpf/progs/test_sk_lookup.c
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Expand Up @@ -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 {
Expand Down Expand Up @@ -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;
}

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