selftests/bpf: Add a selftest to check for incorrect names

Add selftest for cases where btf_name_valid_section() does not properly
check for certain types of names.

Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Link: https://lore.kernel.org/r/20240831054742.364585-1-aha310510@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>

Author: name2965

tools/testing/selftests/bpf/prog_tests/btf.c

@@ -3550,6 +3550,40 @@ static struct btf_raw_test raw_tests[] = {
 	},
 	BTF_STR_SEC("\0x\0?.foo bar:buz"),
 },
+{
+	.descr = "datasec: name with non-printable first char not is ok",
+	.raw_types = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* VAR x */                                     /* [2] */
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
+		BTF_VAR_STATIC,
+		/* DATASEC ?.data */                            /* [3] */
+		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
+		BTF_VAR_SECINFO_ENC(2, 0, 4),
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0x\0\7foo"),
+	.err_str = "Invalid name",
+	.btf_load_err = true,
+},
+{
+	.descr = "datasec: name '\\0' is not ok",
+	.raw_types = {
+		/* int */
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
+		/* VAR x */                                     /* [2] */
+		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
+		BTF_VAR_STATIC,
+		/* DATASEC \0 */                                /* [3] */
+		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
+		BTF_VAR_SECINFO_ENC(2, 0, 4),
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0x\0"),
+	.err_str = "Invalid name",
+	.btf_load_err = true,
+},
 {
 	.descr = "type name '?foo' is not ok",
 	.raw_types = {