selftests/bpf: Test new __sk_buff field hwtstamp

Analogous to the gso_segs selftests introduced in commit d9ff286a0f59
("bpf: allow BPF programs access skb_shared_info->gso_segs field").

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210909220409.8804-3-vfedorenko@novek.ru

5 files changed, 72 insertions, 0 deletions

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 830a18ecffc8..0018d51b93b0 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -8800,6 +8800,7 @@ static __init struct sk_buff *build_test_skb(void)
 	skb_shinfo(skb[0])->gso_type |= SKB_GSO_DODGY;
 	skb_shinfo(skb[0])->gso_segs = 0;
 	skb_shinfo(skb[0])->frag_list = skb[1];
+	skb_shinfo(skb[0])->hwtstamps.hwtstamp = 1000;
 
 	/* adjust skb[0]'s len */
 	skb[0]->len += skb[1]->len;
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 1153b89c9d93..fcb2f493f710 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -507,6 +507,12 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
 	/* gso_size is allowed */
 
 	if (!range_is_zero(__skb, offsetofend(struct __sk_buff, gso_size),
+			   offsetof(struct __sk_buff, hwtstamp)))
+		return -EINVAL;
+
+	/* hwtstamp is allowed */
+
+	if (!range_is_zero(__skb, offsetofend(struct __sk_buff, hwtstamp),
 			   sizeof(struct __sk_buff)))
 		return -EINVAL;
 
@@ -529,6 +535,7 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
 		return -EINVAL;
 	skb_shinfo(skb)->gso_segs = __skb->gso_segs;
 	skb_shinfo(skb)->gso_size = __skb->gso_size;
+	skb_shinfo(skb)->hwtstamps.hwtstamp = __skb->hwtstamp;
 
 	return 0;
 }
@@ -548,6 +555,7 @@ static void convert_skb_to___skb(struct sk_buff *skb, struct __sk_buff *__skb)
 	memcpy(__skb->cb, &cb->data, QDISC_CB_PRIV_LEN);
 	__skb->wire_len = cb->pkt_len;
 	__skb->gso_segs = skb_shinfo(skb)->gso_segs;
+	__skb->hwtstamp = skb_shinfo(skb)->hwtstamps.hwtstamp;
 }
 
 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
diff --git a/tools/testing/selftests/bpf/prog_tests/skb_ctx.c b/tools/testing/selftests/bpf/prog_tests/skb_ctx.c
index 2bf8c687348b..c437e6ba8fe2 100644
--- a/tools/testing/selftests/bpf/prog_tests/skb_ctx.c
+++ b/tools/testing/selftests/bpf/prog_tests/skb_ctx.c
@@ -18,6 +18,7 @@ void test_skb_ctx(void)
 		.gso_segs = 8,
 		.mark = 9,
 		.gso_size = 10,
+		.hwtstamp = 11,
 	};
 	struct bpf_prog_test_run_attr tattr = {
 		.data_in = &pkt_v4,
diff --git a/tools/testing/selftests/bpf/progs/test_skb_ctx.c b/tools/testing/selftests/bpf/progs/test_skb_ctx.c
index bbd5a9c1c4df..ba4dab09d19c 100644
--- a/tools/testing/selftests/bpf/progs/test_skb_ctx.c
+++ b/tools/testing/selftests/bpf/progs/test_skb_ctx.c
@@ -29,6 +29,8 @@ int process(struct __sk_buff *skb)
 		return 1;
 	if (skb->ifindex != 1)
 		return 1;
+	if (skb->hwtstamp != 11)
+		return 1;
 
 	return 0;
 }
diff --git a/tools/testing/selftests/bpf/verifier/ctx_skb.c b/tools/testing/selftests/bpf/verifier/ctx_skb.c
index 2022c0f2cd75..9e1a30b94197 100644
--- a/tools/testing/selftests/bpf/verifier/ctx_skb.c
+++ b/tools/testing/selftests/bpf/verifier/ctx_skb.c
@@ -1058,6 +1058,66 @@
 	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 },
 {
+	"padding after gso_size is not accessible",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+		    offsetofend(struct __sk_buff, gso_size)),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.result_unpriv = REJECT,
+	.errstr = "invalid bpf_context access off=180 size=4",
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
+	"read hwtstamp from CGROUP_SKB",
+	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
+		    offsetof(struct __sk_buff, hwtstamp)),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+},
+{
+	"read hwtstamp from CGROUP_SKB",
+	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1,
+		    offsetof(struct __sk_buff, hwtstamp)),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+},
+{
+	"write hwtstamp from CGROUP_SKB",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0,
+		    offsetof(struct __sk_buff, hwtstamp)),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.result_unpriv = REJECT,
+	.errstr = "invalid bpf_context access off=184 size=8",
+	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
+},
+{
+	"read hwtstamp from CLS",
+	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
+		    offsetof(struct __sk_buff, hwtstamp)),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
 	"check wire_len is not readable by sockets",
 	.insns = {
 		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,