selftests/bpf: Add test cases to test narrower ctx field loads

Add test cases in test_verifier and test_progs.
Negative tests are added in test_verifier as well.
The test in test_progs will compare the value of narrower ctx field
load result vs. the masked value of normal full-field load result,
and will fail if they are not the same.

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 176 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 13341700930c..c0af0195432f 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -1095,6 +1095,59 @@ static struct bpf_test tests[] = {
 		.result = REJECT,
 	},
 	{
+		"check skb->hash byte load permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash)),
+#else
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash) + 3),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+	},
+	{
+		"check skb->hash byte load not permitted 1",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash) + 1),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid bpf_context access",
+		.result = REJECT,
+	},
+	{
+		"check skb->hash byte load not permitted 2",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash) + 2),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid bpf_context access",
+		.result = REJECT,
+	},
+	{
+		"check skb->hash byte load not permitted 3",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash) + 3),
+#else
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash)),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid bpf_context access",
+		.result = REJECT,
+	},
+	{
 		"check cb access: byte, wrong type",
 		.insns = {
 			BPF_MOV64_IMM(BPF_REG_0, 0),
@@ -1188,6 +1241,37 @@ static struct bpf_test tests[] = {
 		.result = REJECT,
 	},
 	{
+		"check skb->hash half load permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash)),
+#else
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash) + 2),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+	},
+	{
+		"check skb->hash half load not permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash) + 2),
+#else
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, hash)),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid bpf_context access",
+		.result = REJECT,
+	},
+	{
 		"check cb access: half, wrong type",
 		.insns = {
 			BPF_MOV64_IMM(BPF_REG_0, 0),
@@ -5103,6 +5187,98 @@ static struct bpf_test tests[] = {
 		},
 		.result = ACCEPT,
 	},
+	{
+		"check bpf_perf_event_data->sample_period byte load permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period)),
+#else
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period) + 7),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_PERF_EVENT,
+	},
+	{
+		"check bpf_perf_event_data->sample_period half load permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period)),
+#else
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period) + 6),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_PERF_EVENT,
+	},
+	{
+		"check bpf_perf_event_data->sample_period word load permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period)),
+#else
+			BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period) + 4),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_PERF_EVENT,
+	},
+	{
+		"check bpf_perf_event_data->sample_period dword load permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct bpf_perf_event_data, sample_period)),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_PERF_EVENT,
+	},
+	{
+		"check skb->data half load not permitted",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, data)),
+#else
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, data) + 2),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = REJECT,
+		.errstr = "invalid bpf_context access",
+	},
+	{
+		"check skb->tc_classid half load not permitted for lwt prog",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+#ifdef __LITTLE_ENDIAN
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, tc_classid)),
+#else
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+				    offsetof(struct __sk_buff, tc_classid) + 2),
+#endif
+			BPF_EXIT_INSN(),
+		},
+		.result = REJECT,
+		.errstr = "invalid bpf_context access",
+		.prog_type = BPF_PROG_TYPE_LWT_IN,
+	},
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)