samples/bpf: add verifier tests

add few tests for "pointer to packet" logic of the verifier
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

samples/bpf/test_verifier.c

@@ -1448,6 +1448,86 @@ static struct bpf_test tests[] = {
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	},
+	{
+		"pkt: test1",
+		.insns = {
+			BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct __sk_buff, data)),
+			BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct __sk_buff, data_end)),
+			BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
+			BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
+	{
+		"pkt: test2",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
+				    offsetof(struct __sk_buff, data_end)),
+			BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct __sk_buff, data)),
+			BPF_MOV64_REG(BPF_REG_5, BPF_REG_3),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
+			BPF_JMP_REG(BPF_JGT, BPF_REG_5, BPF_REG_4, 15),
+			BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_3, 7),
+			BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_3, 12),
+			BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 14),
+			BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct __sk_buff, data)),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_4),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
+			BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 48),
+			BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 48),
+			BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_2),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_3),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 8),
+			BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1,
+				    offsetof(struct __sk_buff, data_end)),
+			BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_3, 4),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
+	{
+		"pkt: test3",
+		.insns = {
+			BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct __sk_buff, data)),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "invalid bpf_context access off=76",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+	},
+	{
+		"pkt: test4",
+		.insns = {
+			BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct __sk_buff, data)),
+			BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct __sk_buff, data_end)),
+			BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
+			BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+			BPF_STX_MEM(BPF_B, BPF_REG_2, BPF_REG_2, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.errstr = "cannot write",
+		.result = REJECT,
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
 };
 
 static int probe_filter_length(struct bpf_insn *fp)