[PATCH 5.9 350/757] selftests/bpf: Fix endianness issues in sk_lookup/ctx_narrow_access

Greg Kroah-Hartman
2020-10-27T15:44:08Z

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