// SPDX-License-Identifier: GPL-2.0-only/* * UBSAN error reporting functions * * Copyright (c) 2014 Samsung Electronics Co., Ltd. * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> */ #include <linux/bitops.h>#include <linux/bug.h>#include <linux/ctype.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/types.h>#include <linux/sched.h>#include <linux/uaccess.h>#include <linux/ubsan.h>#include <kunit/test-bug.h> #include "ubsan.h" #if defined(CONFIG_UBSAN_TRAP) || defined(CONFIG_UBSAN_KVM_EL2)/* * Only include matches for UBSAN checks that are actually compiled in. * The mappings of struct SanitizerKind (the -fsanitize=xxx args) to * enum SanitizerHandler (the traps) in Clang is in clang/lib/CodeGen/. */const char *report_ubsan_failure(u32 check_type){	switch (check_type) {#ifdef CONFIG_UBSAN_BOUNDS	/*	 * SanitizerKind::ArrayBounds and SanitizerKind::LocalBounds	 * emit SanitizerHandler::OutOfBounds.	 */	case ubsan_out_of_bounds:		return "UBSAN: array index out of bounds";#endif#ifdef CONFIG_UBSAN_SHIFT	/*	 * SanitizerKind::ShiftBase and SanitizerKind::ShiftExponent	 * emit SanitizerHandler::ShiftOutOfBounds.	 */	case ubsan_shift_out_of_bounds:		return "UBSAN: shift out of bounds";#endif#if defined(CONFIG_UBSAN_DIV_ZERO) || defined(CONFIG_UBSAN_INTEGER_WRAP)	/*	 * SanitizerKind::IntegerDivideByZero and	 * SanitizerKind::SignedIntegerOverflow emit	 * SanitizerHandler::DivremOverflow.	 */	case ubsan_divrem_overflow:		return "UBSAN: divide/remainder overflow";#endif#ifdef CONFIG_UBSAN_UNREACHABLE	/*	 * SanitizerKind::Unreachable emits	 * SanitizerHandler::BuiltinUnreachable.	 */	case ubsan_builtin_unreachable:		return "UBSAN: unreachable code";#endif#if defined(CONFIG_UBSAN_BOOL) || defined(CONFIG_UBSAN_ENUM)	/*	 * SanitizerKind::Bool and SanitizerKind::Enum emit	 * SanitizerHandler::LoadInvalidValue.	 */	case ubsan_load_invalid_value:		return "UBSAN: loading invalid value";#endif#ifdef CONFIG_UBSAN_ALIGNMENT	/*	 * SanitizerKind::Alignment emits SanitizerHandler::TypeMismatch	 * or SanitizerHandler::AlignmentAssumption.	 */	case ubsan_alignment_assumption:		return "UBSAN: alignment assumption";	case ubsan_type_mismatch:		return "UBSAN: type mismatch";#endif#ifdef CONFIG_UBSAN_INTEGER_WRAP	/*	 * SanitizerKind::SignedIntegerOverflow emits	 * SanitizerHandler::AddOverflow, SanitizerHandler::SubOverflow,	 * or SanitizerHandler::MulOverflow.	 */	case ubsan_add_overflow:		return "UBSAN: integer addition overflow";	case ubsan_sub_overflow:		return "UBSAN: integer subtraction overflow";	case ubsan_mul_overflow:		return "UBSAN: integer multiplication overflow";#endif	default:		return "UBSAN: unrecognized failure code";	}} #endif #ifndef CONFIG_UBSAN_TRAPstatic const char * const type_check_kinds[] = {	"load of",	"store to",	"reference binding to",	"member access within",	"member call on",	"constructor call on",	"downcast of",	"downcast of"}; #define REPORTED_BIT 31 #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)#define COLUMN_MASK (~(1U << REPORTED_BIT))#define LINE_MASK   (~0U)#else#define COLUMN_MASK   (~0U)#define LINE_MASK (~(1U << REPORTED_BIT))#endif #define VALUE_LENGTH 40 static bool was_reported(struct source_location *location){	return test_and_set_bit(REPORTED_BIT, &location->reported);} static bool suppress_report(struct source_location *loc){	return current->in_ubsan || was_reported(loc);} static bool type_is_int(struct type_descriptor *type){	return type->type_kind == type_kind_int;} static bool type_is_signed(struct type_descriptor *type){	WARN_ON(!type_is_int(type));	return  type->type_info & 1;} static unsigned type_bit_width(struct type_descriptor *type){	return 1 << (type->type_info >> 1);} static bool is_inline_int(struct type_descriptor *type){	unsigned inline_bits = sizeof(unsigned long)*8;	unsigned bits = type_bit_width(type); 	WARN_ON(!type_is_int(type)); 	return bits <= inline_bits;} static s_max get_signed_val(struct type_descriptor *type, void *val){	if (is_inline_int(type)) {		unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);		unsigned long ulong_val = (unsigned long)val; 		return ((s_max)ulong_val) << extra_bits >> extra_bits;	} 	if (type_bit_width(type) == 64)		return *(s64 *)val; 	return *(s_max *)val;} static bool val_is_negative(struct type_descriptor *type, void *val){	return type_is_signed(type) && get_signed_val(type, val) < 0;} static u_max get_unsigned_val(struct type_descriptor *type, void *val){	if (is_inline_int(type))		return (unsigned long)val; 	if (type_bit_width(type) == 64)		return *(u64 *)val; 	return *(u_max *)val;} static void val_to_string(char *str, size_t size, struct type_descriptor *type,			void *value){	if (type_is_int(type)) {		if (type_bit_width(type) == 128) {#if defined(CONFIG_ARCH_SUPPORTS_INT128)			u_max val = get_unsigned_val(type, value); 			scnprintf(str, size, "0x%08x%08x%08x%08x",				(u32)(val >> 96),				(u32)(val >> 64),				(u32)(val >> 32),				(u32)(val));#else			WARN_ON(1);#endif		} else if (type_is_signed(type)) {			scnprintf(str, size, "%lld",				(s64)get_signed_val(type, value));		} else {			scnprintf(str, size, "%llu",				(u64)get_unsigned_val(type, value));		}	}} static void ubsan_prologue(struct source_location *loc, const char *reason){	current->in_ubsan++; 	pr_warn(CUT_HERE); 	pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name,		loc->line & LINE_MASK, loc->column & COLUMN_MASK); 	kunit_fail_current_test("%s in %s", reason, loc->file_name);} static void ubsan_epilogue(void){	dump_stack();	pr_warn("---[ end trace ]---\n"); 	current->in_ubsan--; 	check_panic_on_warn("UBSAN");} static void handle_overflow(struct overflow_data *data, void *lhs,			void *rhs, char op){ 	struct type_descriptor *type = data->type;	char lhs_val_str[VALUE_LENGTH];	char rhs_val_str[VALUE_LENGTH]; 	if (suppress_report(&data->location))		return; 	ubsan_prologue(&data->location, type_is_signed(type) ?			"signed-integer-overflow" :			"unsigned-integer-overflow"); 	val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);	val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);	pr_err("%s %c %s cannot be represented in type %s\n",		lhs_val_str,		op,		rhs_val_str,		type->type_name); 	ubsan_epilogue();} void __ubsan_handle_add_overflow(void *data,				void *lhs, void *rhs){ 	handle_overflow(data, lhs, rhs, '+');}EXPORT_SYMBOL(__ubsan_handle_add_overflow); void __ubsan_handle_sub_overflow(void *data,				void *lhs, void *rhs){	handle_overflow(data, lhs, rhs, '-');}EXPORT_SYMBOL(__ubsan_handle_sub_overflow); void __ubsan_handle_mul_overflow(void *data,				void *lhs, void *rhs){	handle_overflow(data, lhs, rhs, '*');}EXPORT_SYMBOL(__ubsan_handle_mul_overflow); void __ubsan_handle_negate_overflow(void *_data, void *old_val){	struct overflow_data *data = _data;	char old_val_str[VALUE_LENGTH]; 	if (suppress_report(&data->location))		return; 	ubsan_prologue(&data->location, "negation-overflow"); 	val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val); 	pr_err("negation of %s cannot be represented in type %s:\n",		old_val_str, data->type->type_name); 	ubsan_epilogue();}EXPORT_SYMBOL(__ubsan_handle_negate_overflow); void __ubsan_handle_implicit_conversion(void *_data, void *from_val, void *to_val){	struct implicit_conversion_data *data = _data;	char from_val_str[VALUE_LENGTH];	char to_val_str[VALUE_LENGTH]; 	if (suppress_report(&data->location))		return; 	val_to_string(from_val_str, sizeof(from_val_str), data->from_type, from_val);	val_to_string(to_val_str, sizeof(to_val_str), data->to_type, to_val); 	ubsan_prologue(&data->location, "implicit-conversion"); 	pr_err("cannot represent %s value %s during %s %s, truncated to %s\n",		data->from_type->type_name,		from_val_str,		type_check_kinds[data->type_check_kind],		data->to_type->type_name,		to_val_str); 	ubsan_epilogue();}EXPORT_SYMBOL(__ubsan_handle_implicit_conversion); void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs){	struct overflow_data *data = _data;	char lhs_val_str[VALUE_LENGTH]; 	if (suppress_report(&data->location))		return; 	ubsan_prologue(&data->location, "division-overflow"); 	val_to_string(lhs_val_str, sizeof(lhs_val_str), data->type, lhs); 	if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1)		pr_err("division of %s by -1 cannot be represented in type %s\n",			lhs_val_str, data->type->type_name);	else		pr_err("division by zero\n"); 	ubsan_epilogue();}EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); static void handle_null_ptr_deref(struct type_mismatch_data_common *data){	if (suppress_report(data->location))		return; 	ubsan_prologue(data->location, "null-ptr-deref"); 	pr_err("%s null pointer of type %s\n",		type_check_kinds[data->type_check_kind],		data->type->type_name); 	ubsan_epilogue();} static void handle_misaligned_access(struct type_mismatch_data_common *data,				unsigned long ptr){	if (suppress_report(data->location))		return; 	ubsan_prologue(data->location, "misaligned-access"); 	pr_err("%s misaligned address %p for type %s\n",		type_check_kinds[data->type_check_kind],		(void *)ptr, data->type->type_name);	pr_err("which requires %ld byte alignment\n", data->alignment); 	ubsan_epilogue();} static void handle_object_size_mismatch(struct type_mismatch_data_common *data,					unsigned long ptr){	if (suppress_report(data->location))		return; 	ubsan_prologue(data->location, "object-size-mismatch");	pr_err("%s address %p with insufficient space\n",		type_check_kinds[data->type_check_kind],		(void *) ptr);	pr_err("for an object of type %s\n", data->type->type_name);	ubsan_epilogue();} static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,				unsigned long ptr){	unsigned long flags = user_access_save(); 	if (!ptr)		handle_null_ptr_deref(data);	else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))		handle_misaligned_access(data, ptr);	else		handle_object_size_mismatch(data, ptr); 	user_access_restore(flags);} void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,				void *ptr){	struct type_mismatch_data_common common_data = {		.location = &data->location,		.type = data->type,		.alignment = data->alignment,		.type_check_kind = data->type_check_kind	}; 	ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);}EXPORT_SYMBOL(__ubsan_handle_type_mismatch); void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr){	struct type_mismatch_data_v1 *data = _data;	struct type_mismatch_data_common common_data = {		.location = &data->location,		.type = data->type,		.alignment = 1UL << data->log_alignment,		.type_check_kind = data->type_check_kind	}; 	ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);}EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1); void __ubsan_handle_out_of_bounds(void *_data, void *index){	struct out_of_bounds_data *data = _data;	char index_str[VALUE_LENGTH]; 	if (suppress_report(&data->location))		return; 	ubsan_prologue(&data->location, "array-index-out-of-bounds"); 	val_to_string(index_str, sizeof(index_str), data->index_type, index);	pr_err("index %s is out of range for type %s\n", index_str,		data->array_type->type_name);	ubsan_epilogue();}EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs){	struct shift_out_of_bounds_data *data = _data;	struct type_descriptor *rhs_type = data->rhs_type;	struct type_descriptor *lhs_type = data->lhs_type;	char rhs_str[VALUE_LENGTH];	char lhs_str[VALUE_LENGTH];	unsigned long ua_flags = user_access_save(); 	if (suppress_report(&data->location))		goto out; 	ubsan_prologue(&data->location, "shift-out-of-bounds"); 	val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);	val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); 	if (val_is_negative(rhs_type, rhs))		pr_err("shift exponent %s is negative\n", rhs_str); 	else if (get_unsigned_val(rhs_type, rhs) >=		type_bit_width(lhs_type))		pr_err("shift exponent %s is too large for %u-bit type %s\n",			rhs_str,			type_bit_width(lhs_type),			lhs_type->type_name);	else if (val_is_negative(lhs_type, lhs))		pr_err("left shift of negative value %s\n",			lhs_str);	else		pr_err("left shift of %s by %s places cannot be"			" represented in type %s\n",			lhs_str, rhs_str,			lhs_type->type_name); 	ubsan_epilogue();out:	user_access_restore(ua_flags);}EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);  

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