From 4c6be9cb63ff66ce49a6f733c1e00d1889f2c95f Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Sun, 10 Apr 2022 20:37:51 +0300
Subject: add basic ubsan and fix issues reported by it

---
 lib/ubsan.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 lib/ubsan.c

(limited to 'lib/ubsan.c')

diff --git a/lib/ubsan.c b/lib/ubsan.c
new file mode 100644
index 0000000..0a05e2e
--- /dev/null
+++ b/lib/ubsan.c
@@ -0,0 +1,159 @@
+#include <apos/types.h>
+#include <apos/debug.h>
+
+/* mostly lifted from https://github.com/Abb1x/tinyubsan/blob/master/src/tinyubsan.c */
+
+struct tu_source_location {
+	const char *file;
+	uint32_t line;
+	uint32_t column;
+};
+
+struct tu_type_descriptor {
+	uint16_t kind;
+	uint16_t info;
+	char name[];
+};
+
+struct tu_overflow_data {
+	struct tu_source_location location;
+	struct tu_type_descriptor *type;
+};
+
+struct tu_shift_out_of_bounds_data {
+	struct tu_source_location location;
+	struct tu_type_descriptor *left_type;
+	struct tu_type_descriptor *right_type;
+};
+
+struct tu_invalid_value_data {
+	struct tu_source_location location;
+	struct tu_type_descriptor *type;
+};
+
+struct tu_array_out_of_bounds_data {
+	struct tu_source_location location;
+	struct tu_type_descriptor *array_type;
+	struct tu_type_descriptor *index_type;
+};
+
+struct tu_type_mismatch_v1_data {
+	struct tu_source_location location;
+	struct tu_type_descriptor *type;
+	unsigned char log_alignment;
+	unsigned char type_check_kind;
+};
+
+struct tu_negative_vla_data {
+	struct tu_source_location location;
+	struct tu_type_descriptor *type;
+};
+
+struct tu_nonnull_return_data {
+	struct tu_source_location location;
+};
+
+struct tu_nonnull_arg_data {
+	struct tu_source_location location;
+};
+
+struct tu_unreachable_data {
+	struct tu_source_location location;
+};
+
+struct tu_invalid_builtin_data {
+	struct tu_source_location location;
+	unsigned char kind;
+};
+
+static void tu_print_location(const char *message,
+                              struct tu_source_location loc)
+{
+	bug("ubsan: %s at file %s, line %d, column %d\n", message, loc.file,
+	    loc.line, loc.column);
+}
+
+void __ubsan_handle_add_overflow(struct tu_overflow_data *data)
+{
+	tu_print_location("addition overflow", data->location);
+}
+
+void __ubsan_handle_sub_overflow(struct tu_overflow_data *data)
+{
+	tu_print_location("subtraction overflow", data->location);
+}
+
+void __ubsan_handle_mul_overflow(struct tu_overflow_data *data)
+{
+	tu_print_location("multiplication overflow", data->location);
+}
+
+void __ubsan_handle_divrem_overflow(struct tu_overflow_data *data)
+{
+	tu_print_location("division overflow", data->location);
+}
+
+void __ubsan_handle_negate_overflow(struct tu_overflow_data *data)
+{
+	tu_print_location("negation overflow", data->location);
+}
+
+void __ubsan_handle_pointer_overflow(struct tu_overflow_data *data)
+{
+	tu_print_location("pointer overflow", data->location);
+}
+
+void __ubsan_handle_shift_out_of_bounds(struct tu_shift_out_of_bounds_data *data)
+{
+	tu_print_location("shift out of bounds", data->location);
+}
+
+void __ubsan_handle_load_invalid_value(struct tu_invalid_value_data *data)
+{
+	tu_print_location("invalid load value", data->location);
+}
+
+void __ubsan_handle_out_of_bounds(struct tu_array_out_of_bounds_data *data)
+{
+	tu_print_location("array out of bounds", data->location);
+}
+
+void __ubsan_handle_type_mismatch_v1(struct tu_type_mismatch_v1_data *data,
+                                     uintptr_t ptr)
+{
+	if (!ptr) {
+		tu_print_location("use of NULL pointer", data->location);
+	}
+
+	else if (ptr & ((1 << data->log_alignment) - 1)) {
+		tu_print_location("use of misaligned pointer", data->location);
+	} else {
+		tu_print_location("no space for object", data->location);
+	}
+}
+
+void __ubsan_handle_vla_bound_not_positive(struct tu_negative_vla_data *data)
+{
+	tu_print_location("variable-length argument is negative",
+	                  data->location);
+}
+
+void __ubsan_handle_nonnull_return(struct tu_nonnull_return_data *data)
+{
+	tu_print_location("non-null return is null", data->location);
+}
+
+void __ubsan_handle_nonnull_arg(struct tu_nonnull_arg_data *data)
+{
+	tu_print_location("non-null argument is null", data->location);
+}
+
+void __ubsan_handle_builtin_unreachable(struct tu_unreachable_data *data)
+{
+	tu_print_location("unreachable code reached", data->location);
+}
+
+void __ubsan_handle_invalid_builtin(struct tu_invalid_builtin_data *data)
+{
+	tu_print_location("invalid builtin", data->location);
+}
-- 
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