cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ubsan.c (9978B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * UBSAN error reporting functions
      4 *
      5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
      6 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      7 */
      8
      9#include <linux/bitops.h>
     10#include <linux/bug.h>
     11#include <linux/ctype.h>
     12#include <linux/init.h>
     13#include <linux/kernel.h>
     14#include <linux/types.h>
     15#include <linux/sched.h>
     16#include <linux/uaccess.h>
     17#include <kunit/test-bug.h>
     18
     19#include "ubsan.h"
     20
     21static const char * const type_check_kinds[] = {
     22	"load of",
     23	"store to",
     24	"reference binding to",
     25	"member access within",
     26	"member call on",
     27	"constructor call on",
     28	"downcast of",
     29	"downcast of"
     30};
     31
     32#define REPORTED_BIT 31
     33
     34#if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
     35#define COLUMN_MASK (~(1U << REPORTED_BIT))
     36#define LINE_MASK   (~0U)
     37#else
     38#define COLUMN_MASK   (~0U)
     39#define LINE_MASK (~(1U << REPORTED_BIT))
     40#endif
     41
     42#define VALUE_LENGTH 40
     43
     44static bool was_reported(struct source_location *location)
     45{
     46	return test_and_set_bit(REPORTED_BIT, &location->reported);
     47}
     48
     49static bool suppress_report(struct source_location *loc)
     50{
     51	return current->in_ubsan || was_reported(loc);
     52}
     53
     54static bool type_is_int(struct type_descriptor *type)
     55{
     56	return type->type_kind == type_kind_int;
     57}
     58
     59static bool type_is_signed(struct type_descriptor *type)
     60{
     61	WARN_ON(!type_is_int(type));
     62	return  type->type_info & 1;
     63}
     64
     65static unsigned type_bit_width(struct type_descriptor *type)
     66{
     67	return 1 << (type->type_info >> 1);
     68}
     69
     70static bool is_inline_int(struct type_descriptor *type)
     71{
     72	unsigned inline_bits = sizeof(unsigned long)*8;
     73	unsigned bits = type_bit_width(type);
     74
     75	WARN_ON(!type_is_int(type));
     76
     77	return bits <= inline_bits;
     78}
     79
     80static s_max get_signed_val(struct type_descriptor *type, void *val)
     81{
     82	if (is_inline_int(type)) {
     83		unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);
     84		unsigned long ulong_val = (unsigned long)val;
     85
     86		return ((s_max)ulong_val) << extra_bits >> extra_bits;
     87	}
     88
     89	if (type_bit_width(type) == 64)
     90		return *(s64 *)val;
     91
     92	return *(s_max *)val;
     93}
     94
     95static bool val_is_negative(struct type_descriptor *type, void *val)
     96{
     97	return type_is_signed(type) && get_signed_val(type, val) < 0;
     98}
     99
    100static u_max get_unsigned_val(struct type_descriptor *type, void *val)
    101{
    102	if (is_inline_int(type))
    103		return (unsigned long)val;
    104
    105	if (type_bit_width(type) == 64)
    106		return *(u64 *)val;
    107
    108	return *(u_max *)val;
    109}
    110
    111static void val_to_string(char *str, size_t size, struct type_descriptor *type,
    112			void *value)
    113{
    114	if (type_is_int(type)) {
    115		if (type_bit_width(type) == 128) {
    116#if defined(CONFIG_ARCH_SUPPORTS_INT128)
    117			u_max val = get_unsigned_val(type, value);
    118
    119			scnprintf(str, size, "0x%08x%08x%08x%08x",
    120				(u32)(val >> 96),
    121				(u32)(val >> 64),
    122				(u32)(val >> 32),
    123				(u32)(val));
    124#else
    125			WARN_ON(1);
    126#endif
    127		} else if (type_is_signed(type)) {
    128			scnprintf(str, size, "%lld",
    129				(s64)get_signed_val(type, value));
    130		} else {
    131			scnprintf(str, size, "%llu",
    132				(u64)get_unsigned_val(type, value));
    133		}
    134	}
    135}
    136
    137static void ubsan_prologue(struct source_location *loc, const char *reason)
    138{
    139	current->in_ubsan++;
    140
    141	pr_err("========================================"
    142		"========================================\n");
    143	pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name,
    144		loc->line & LINE_MASK, loc->column & COLUMN_MASK);
    145
    146	kunit_fail_current_test("%s in %s", reason, loc->file_name);
    147}
    148
    149static void ubsan_epilogue(void)
    150{
    151	dump_stack();
    152	pr_err("========================================"
    153		"========================================\n");
    154
    155	current->in_ubsan--;
    156
    157	if (panic_on_warn)
    158		panic("panic_on_warn set ...\n");
    159}
    160
    161void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
    162{
    163	struct overflow_data *data = _data;
    164	char rhs_val_str[VALUE_LENGTH];
    165
    166	if (suppress_report(&data->location))
    167		return;
    168
    169	ubsan_prologue(&data->location, "division-overflow");
    170
    171	val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);
    172
    173	if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1)
    174		pr_err("division of %s by -1 cannot be represented in type %s\n",
    175			rhs_val_str, data->type->type_name);
    176	else
    177		pr_err("division by zero\n");
    178
    179	ubsan_epilogue();
    180}
    181EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
    182
    183static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
    184{
    185	if (suppress_report(data->location))
    186		return;
    187
    188	ubsan_prologue(data->location, "null-ptr-deref");
    189
    190	pr_err("%s null pointer of type %s\n",
    191		type_check_kinds[data->type_check_kind],
    192		data->type->type_name);
    193
    194	ubsan_epilogue();
    195}
    196
    197static void handle_misaligned_access(struct type_mismatch_data_common *data,
    198				unsigned long ptr)
    199{
    200	if (suppress_report(data->location))
    201		return;
    202
    203	ubsan_prologue(data->location, "misaligned-access");
    204
    205	pr_err("%s misaligned address %p for type %s\n",
    206		type_check_kinds[data->type_check_kind],
    207		(void *)ptr, data->type->type_name);
    208	pr_err("which requires %ld byte alignment\n", data->alignment);
    209
    210	ubsan_epilogue();
    211}
    212
    213static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
    214					unsigned long ptr)
    215{
    216	if (suppress_report(data->location))
    217		return;
    218
    219	ubsan_prologue(data->location, "object-size-mismatch");
    220	pr_err("%s address %p with insufficient space\n",
    221		type_check_kinds[data->type_check_kind],
    222		(void *) ptr);
    223	pr_err("for an object of type %s\n", data->type->type_name);
    224	ubsan_epilogue();
    225}
    226
    227static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
    228				unsigned long ptr)
    229{
    230	unsigned long flags = user_access_save();
    231
    232	if (!ptr)
    233		handle_null_ptr_deref(data);
    234	else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))
    235		handle_misaligned_access(data, ptr);
    236	else
    237		handle_object_size_mismatch(data, ptr);
    238
    239	user_access_restore(flags);
    240}
    241
    242void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
    243				void *ptr)
    244{
    245	struct type_mismatch_data_common common_data = {
    246		.location = &data->location,
    247		.type = data->type,
    248		.alignment = data->alignment,
    249		.type_check_kind = data->type_check_kind
    250	};
    251
    252	ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
    253}
    254EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
    255
    256void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr)
    257{
    258	struct type_mismatch_data_v1 *data = _data;
    259	struct type_mismatch_data_common common_data = {
    260		.location = &data->location,
    261		.type = data->type,
    262		.alignment = 1UL << data->log_alignment,
    263		.type_check_kind = data->type_check_kind
    264	};
    265
    266	ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
    267}
    268EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
    269
    270void __ubsan_handle_out_of_bounds(void *_data, void *index)
    271{
    272	struct out_of_bounds_data *data = _data;
    273	char index_str[VALUE_LENGTH];
    274
    275	if (suppress_report(&data->location))
    276		return;
    277
    278	ubsan_prologue(&data->location, "array-index-out-of-bounds");
    279
    280	val_to_string(index_str, sizeof(index_str), data->index_type, index);
    281	pr_err("index %s is out of range for type %s\n", index_str,
    282		data->array_type->type_name);
    283	ubsan_epilogue();
    284}
    285EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
    286
    287void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs)
    288{
    289	struct shift_out_of_bounds_data *data = _data;
    290	struct type_descriptor *rhs_type = data->rhs_type;
    291	struct type_descriptor *lhs_type = data->lhs_type;
    292	char rhs_str[VALUE_LENGTH];
    293	char lhs_str[VALUE_LENGTH];
    294	unsigned long ua_flags = user_access_save();
    295
    296	if (suppress_report(&data->location))
    297		goto out;
    298
    299	ubsan_prologue(&data->location, "shift-out-of-bounds");
    300
    301	val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
    302	val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
    303
    304	if (val_is_negative(rhs_type, rhs))
    305		pr_err("shift exponent %s is negative\n", rhs_str);
    306
    307	else if (get_unsigned_val(rhs_type, rhs) >=
    308		type_bit_width(lhs_type))
    309		pr_err("shift exponent %s is too large for %u-bit type %s\n",
    310			rhs_str,
    311			type_bit_width(lhs_type),
    312			lhs_type->type_name);
    313	else if (val_is_negative(lhs_type, lhs))
    314		pr_err("left shift of negative value %s\n",
    315			lhs_str);
    316	else
    317		pr_err("left shift of %s by %s places cannot be"
    318			" represented in type %s\n",
    319			lhs_str, rhs_str,
    320			lhs_type->type_name);
    321
    322	ubsan_epilogue();
    323out:
    324	user_access_restore(ua_flags);
    325}
    326EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
    327
    328
    329void __ubsan_handle_builtin_unreachable(void *_data)
    330{
    331	struct unreachable_data *data = _data;
    332	ubsan_prologue(&data->location, "unreachable");
    333	pr_err("calling __builtin_unreachable()\n");
    334	ubsan_epilogue();
    335	panic("can't return from __builtin_unreachable()");
    336}
    337EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
    338
    339void __ubsan_handle_load_invalid_value(void *_data, void *val)
    340{
    341	struct invalid_value_data *data = _data;
    342	char val_str[VALUE_LENGTH];
    343
    344	if (suppress_report(&data->location))
    345		return;
    346
    347	ubsan_prologue(&data->location, "invalid-load");
    348
    349	val_to_string(val_str, sizeof(val_str), data->type, val);
    350
    351	pr_err("load of value %s is not a valid value for type %s\n",
    352		val_str, data->type->type_name);
    353
    354	ubsan_epilogue();
    355}
    356EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
    357
    358void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
    359					 unsigned long align,
    360					 unsigned long offset);
    361void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
    362					 unsigned long align,
    363					 unsigned long offset)
    364{
    365	struct alignment_assumption_data *data = _data;
    366	unsigned long real_ptr;
    367
    368	if (suppress_report(&data->location))
    369		return;
    370
    371	ubsan_prologue(&data->location, "alignment-assumption");
    372
    373	if (offset)
    374		pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed",
    375		       align, offset, data->type->type_name);
    376	else
    377		pr_err("assumption of %lu byte alignment for pointer of type %s failed",
    378		       align, data->type->type_name);
    379
    380	real_ptr = ptr - offset;
    381	pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes",
    382	       offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0),
    383	       real_ptr & (align - 1));
    384
    385	ubsan_epilogue();
    386}
    387EXPORT_SYMBOL(__ubsan_handle_alignment_assumption);