bpf: add verifier tests for BPF_PROG_TYPE_SK_MSG

Test read and writes for BPF_PROG_TYPE_SK_MSG.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/test_verifier.c

@@ -1596,6 +1596,60 @@ static struct bpf_test tests[] = {
 		.result = ACCEPT,
 		.prog_type = BPF_PROG_TYPE_SK_SKB,
 	},
+	{
+		"direct packet read for SK_MSG",
+		.insns = {
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct sk_msg_md, data)),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct sk_msg_md, 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_SK_MSG,
+	},
+	{
+		"direct packet write for SK_MSG",
+		.insns = {
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct sk_msg_md, data)),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct sk_msg_md, 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(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_SK_MSG,
+	},
+	{
+		"overlapping checks for direct packet access SK_MSG",
+		.insns = {
+			BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct sk_msg_md, data)),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct sk_msg_md, 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, 4),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
+			BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
+			BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_2, 6),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.prog_type = BPF_PROG_TYPE_SK_MSG,
+	},
 	{
 		"check skb->mark is not writeable by sockets",
 		.insns = {