From: mbuhl <mbuhl@openbsd.org>
Date: Fri, 6 Sep 2024 13:31:59 +0000 (+0000)
Subject: Fix KUBSAN by adding invalid builtin detection, as needed by our current clang.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=202e2461a0d9a8e3abe70503423141a09ea1c4f4;p=openbsd

Fix KUBSAN by adding invalid builtin detection, as needed by our current clang.
ok anton@
---

diff --git a/share/man/man4/kubsan.4 b/share/man/man4/kubsan.4
index 6165a1ebbb5..db3866d2b66 100644
--- a/share/man/man4/kubsan.4
+++ b/share/man/man4/kubsan.4
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: kubsan.4,v 1.4 2024/09/06 13:30:59 mbuhl Exp $
+.\"	$OpenBSD: kubsan.4,v 1.5 2024/09/06 13:31:59 mbuhl Exp $
 .\"
 .\" Copyright (c) 2019 Anton Lindqvist <anton@openbsd.org>
 .\"
@@ -69,6 +69,8 @@ Passing
 .Dv NULL
 as the value for a function argument annotated with
 .Dv __nonnull__ .
+.It Invalid builtin
+Passing zero to a compiler builtin where not allowed.
 .It Invalid load
 Loading a value that cannot be represented by the destination type.
 .It Type mismatch
diff --git a/sys/kern/subr_kubsan.c b/sys/kern/subr_kubsan.c
index 9655500288d..967140fc298 100644
--- a/sys/kern/subr_kubsan.c
+++ b/sys/kern/subr_kubsan.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_kubsan.c,v 1.12 2019/11/06 19:16:48 anton Exp $	*/
+/*	$OpenBSD: subr_kubsan.c,v 1.13 2024/09/06 13:31:59 mbuhl Exp $	*/
 
 /*
  * Copyright (c) 2019 Anton Lindqvist <anton@openbsd.org>
@@ -38,6 +38,7 @@
 struct kubsan_report {
 	enum {
 		KUBSAN_FLOAT_CAST_OVERFLOW,
+		KUBSAN_INVALID_BUILTIN,
 		KUBSAN_INVALID_VALUE,
 		KUBSAN_NEGATE_OVERFLOW,
 		KUBSAN_NONNULL_ARG,
@@ -57,6 +58,10 @@ struct kubsan_report {
 			unsigned long v_val;
 		} v_float_cast_overflow;
 
+		struct {
+			const struct invalid_builtin_data *v_data;
+		} v_invalid_builtin;
+
 		struct {
 			const struct invalid_value_data *v_data;
 			unsigned long v_val;
@@ -102,6 +107,7 @@ struct kubsan_report {
 	} kr_u;
 };
 #define kr_float_cast_overflow		kr_u.v_float_cast_overflow
+#define kr_invalid_builtin		kr_u.v_invalid_builtin
 #define kr_invalid_value		kr_u.v_invalid_value
 #define kr_negate_overflow		kr_u.v_negate_overflow
 #define kr_nonnull_arg			kr_u.v_nonnull_arg
@@ -129,6 +135,11 @@ struct float_cast_overflow_data {
 	struct type_descriptor *d_ttype;	/* to type */
 };
 
+struct invalid_builtin_data {
+	struct source_location d_src;
+	uint8_t d_kind;
+};
+
 struct invalid_value_data {
 	struct source_location d_src;
 	struct type_descriptor *d_type;
@@ -264,6 +275,18 @@ __ubsan_handle_float_cast_overflow(struct float_cast_overflow_data *data,
 	kubsan_defer_report(&kr);
 }
 
+void
+__ubsan_handle_invalid_builtin(struct invalid_builtin_data *data)
+{
+	struct kubsan_report kr = {
+		.kr_type		= KUBSAN_INVALID_VALUE,
+		.kr_src			= &data->d_src,
+		.kr_invalid_builtin	= { data },
+	};
+
+	kubsan_defer_report(&kr);
+}
+
 void
 __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
     unsigned long val)
@@ -562,6 +585,16 @@ again:
 			break;
 		}
 
+		case KUBSAN_INVALID_BUILTIN: {
+			const struct invalid_builtin_data *data =
+			    kr->kr_invalid_builtin.v_data;
+
+			printf("kubsan: %s: invalid builtin: passing zero to "
+			    "%s, which is not a valid argument\n",
+			    bloc, kubsan_kind(data->d_kind));
+			break;
+		}
+
 		case KUBSAN_INVALID_VALUE: {
 			const struct invalid_value_data *data =
 			    kr->kr_invalid_value.v_data;