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Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_sk_lookup.c')
-rw-r--r--tools/testing/selftests/bpf/progs/test_sk_lookup.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_sk_lookup.c b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
index 83b0aaa52ef7..6058dcb11b36 100644
--- a/tools/testing/selftests/bpf/progs/test_sk_lookup.c
+++ b/tools/testing/selftests/bpf/progs/test_sk_lookup.c
@@ -392,6 +392,7 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)
{
struct bpf_sock *sk;
int err, family;
+ __u32 val_u32;
bool v4;
v4 = (ctx->family == AF_INET);
@@ -412,12 +413,22 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx)
/* Narrow loads from remote_port field. Expect SRC_PORT. */
if (LSB(ctx->remote_port, 0) != ((SRC_PORT >> 0) & 0xff) ||
- LSB(ctx->remote_port, 1) != ((SRC_PORT >> 8) & 0xff) ||
- LSB(ctx->remote_port, 2) != 0 || LSB(ctx->remote_port, 3) != 0)
+ LSB(ctx->remote_port, 1) != ((SRC_PORT >> 8) & 0xff))
return SK_DROP;
if (LSW(ctx->remote_port, 0) != SRC_PORT)
return SK_DROP;
+ /*
+ * NOTE: 4-byte load from bpf_sk_lookup at remote_port offset
+ * is quirky. It gets rewritten by the access converter to a
+ * 2-byte load for backward compatibility. Treating the load
+ * result as a be16 value makes the code portable across
+ * little- and big-endian platforms.
+ */
+ val_u32 = *(__u32 *)&ctx->remote_port;
+ if (val_u32 != SRC_PORT)
+ return SK_DROP;
+
/* Narrow loads from local_port field. Expect DST_PORT. */
if (LSB(ctx->local_port, 0) != ((DST_PORT >> 0) & 0xff) ||
LSB(ctx->local_port, 1) != ((DST_PORT >> 8) & 0xff) ||