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| author | Jakub Sitnicki <jakub@cloudflare.com> | 2022-02-09 19:43:33 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-02-09 20:40:45 +0100 |
| commit | 2ed0dc5937d38f282841d22c5a5354ec264c7b8d (patch) | |
| tree | 427e6ef1e3229dae55160bdb5c69896f5ddfa7f5 | |
| parent | bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide (diff) | |
| download | linux-2ed0dc5937d38f282841d22c5a5354ec264c7b8d.tar.xz linux-2ed0dc5937d38f282841d22c5a5354ec264c7b8d.zip | |
selftests/bpf: Cover 4-byte load from remote_port in bpf_sk_lookup
Extend the context access tests for sk_lookup prog to cover the surprising
case of a 4-byte load from the remote_port field, where the expected value
is actually shifted by 16 bits.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220209184333.654927-3-jakub@cloudflare.com
| -rw-r--r-- | tools/include/uapi/linux/bpf.h | 3 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_sk_lookup.c | 6 |
2 files changed, 8 insertions, 1 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index a7f0ddedac1f..afe3d0d7f5f2 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -6453,7 +6453,8 @@ struct bpf_sk_lookup { __u32 protocol; /* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */ __u32 remote_ip4; /* Network byte order */ __u32 remote_ip6[4]; /* Network byte order */ - __u32 remote_port; /* Network byte order */ + __be16 remote_port; /* Network byte order */ + __u16 :16; /* Zero padding */ __u32 local_ip4; /* Network byte order */ __u32 local_ip6[4]; /* Network byte order */ __u32 local_port; /* Host byte order */ diff --git a/tools/testing/selftests/bpf/progs/test_sk_lookup.c b/tools/testing/selftests/bpf/progs/test_sk_lookup.c index 83b0aaa52ef7..bf5b7caefdd0 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); @@ -418,6 +419,11 @@ int ctx_narrow_access(struct bpf_sk_lookup *ctx) if (LSW(ctx->remote_port, 0) != SRC_PORT) return SK_DROP; + /* Load from remote_port field with zero padding (backward compatibility) */ + val_u32 = *(__u32 *)&ctx->remote_port; + if (val_u32 != bpf_htonl(bpf_ntohs(SRC_PORT) << 16)) + 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) || |