linux/lib/ubsan.c
Andrey Ryabinin bac7a1fff7 lib/ubsan: remove returns-nonnull-attribute checks
Similarly to type mismatch checks, new GCC 8.x and Clang also changed for
ABI for returns_nonnull checks.  While we can update our code to conform
the new ABI it's more reasonable to just remove it.  Because it's just
dead code, we don't have any single user of returns_nonnull attribute in
the whole kernel.

And AFAIU the advantage that this attribute could bring would be mitigated
by -fno-delete-null-pointer-checks cflag that we use to build the kernel.
So it's unlikely we will have a lot of returns_nonnull attribute in
future.

So let's just remove the code, it has no use.

[aryabinin@virtuozzo.com: fix warning]
  Link: http://lkml.kernel.org/r/20180122165711.11510-1-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/20180119152853.16806-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Sodagudi Prasad <psodagud@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06 18:32:46 -08:00

461 lines
11 KiB
C

/*
* UBSAN error reporting functions
*
* Copyright (c) 2014 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#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 "ubsan.h"
const char *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 void print_source_location(const char *prefix,
struct source_location *loc)
{
pr_err("%s %s:%d:%d\n", prefix, loc->file_name,
loc->line & LINE_MASK, loc->column & COLUMN_MASK);
}
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, unsigned long val)
{
if (is_inline_int(type)) {
unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);
return ((s_max)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, unsigned long val)
{
return type_is_signed(type) && get_signed_val(type, val) < 0;
}
static u_max get_unsigned_val(struct type_descriptor *type, unsigned long val)
{
if (is_inline_int(type))
return 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,
unsigned long value)
{
if (type_is_int(type)) {
if (type_bit_width(type) == 128) {
#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_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 DEFINE_SPINLOCK(report_lock);
static void ubsan_prologue(struct source_location *location,
unsigned long *flags)
{
current->in_ubsan++;
spin_lock_irqsave(&report_lock, *flags);
pr_err("========================================"
"========================================\n");
print_source_location("UBSAN: Undefined behaviour in", location);
}
static void ubsan_epilogue(unsigned long *flags)
{
dump_stack();
pr_err("========================================"
"========================================\n");
spin_unlock_irqrestore(&report_lock, *flags);
current->in_ubsan--;
}
static void handle_overflow(struct overflow_data *data, unsigned long lhs,
unsigned long rhs, char op)
{
struct type_descriptor *type = data->type;
unsigned long flags;
char lhs_val_str[VALUE_LENGTH];
char rhs_val_str[VALUE_LENGTH];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
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 integer overflow:\n",
type_is_signed(type) ? "signed" : "unsigned");
pr_err("%s %c %s cannot be represented in type %s\n",
lhs_val_str,
op,
rhs_val_str,
type->type_name);
ubsan_epilogue(&flags);
}
void __ubsan_handle_add_overflow(struct overflow_data *data,
unsigned long lhs,
unsigned long rhs)
{
handle_overflow(data, lhs, rhs, '+');
}
EXPORT_SYMBOL(__ubsan_handle_add_overflow);
void __ubsan_handle_sub_overflow(struct overflow_data *data,
unsigned long lhs,
unsigned long rhs)
{
handle_overflow(data, lhs, rhs, '-');
}
EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
void __ubsan_handle_mul_overflow(struct overflow_data *data,
unsigned long lhs,
unsigned long rhs)
{
handle_overflow(data, lhs, rhs, '*');
}
EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
void __ubsan_handle_negate_overflow(struct overflow_data *data,
unsigned long old_val)
{
unsigned long flags;
char old_val_str[VALUE_LENGTH];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
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(&flags);
}
EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
void __ubsan_handle_divrem_overflow(struct overflow_data *data,
unsigned long lhs,
unsigned long rhs)
{
unsigned long flags;
char rhs_val_str[VALUE_LENGTH];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);
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",
rhs_val_str, data->type->type_name);
else
pr_err("division by zero\n");
ubsan_epilogue(&flags);
}
EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
{
unsigned long flags;
if (suppress_report(data->location))
return;
ubsan_prologue(data->location, &flags);
pr_err("%s null pointer of type %s\n",
type_check_kinds[data->type_check_kind],
data->type->type_name);
ubsan_epilogue(&flags);
}
static void handle_misaligned_access(struct type_mismatch_data_common *data,
unsigned long ptr)
{
unsigned long flags;
if (suppress_report(data->location))
return;
ubsan_prologue(data->location, &flags);
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(&flags);
}
static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
unsigned long ptr)
{
unsigned long flags;
if (suppress_report(data->location))
return;
ubsan_prologue(data->location, &flags);
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(&flags);
}
static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
unsigned long ptr)
{
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);
}
void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
unsigned long 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, ptr);
}
EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data,
unsigned long ptr)
{
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, ptr);
}
EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data,
unsigned long bound)
{
unsigned long flags;
char bound_str[VALUE_LENGTH];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
val_to_string(bound_str, sizeof(bound_str), data->type, bound);
pr_err("variable length array bound value %s <= 0\n", bound_str);
ubsan_epilogue(&flags);
}
EXPORT_SYMBOL(__ubsan_handle_vla_bound_not_positive);
void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data,
unsigned long index)
{
unsigned long flags;
char index_str[VALUE_LENGTH];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
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(&flags);
}
EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
unsigned long lhs, unsigned long rhs)
{
unsigned long flags;
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];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
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(&flags);
}
EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
void __noreturn
__ubsan_handle_builtin_unreachable(struct unreachable_data *data)
{
unsigned long flags;
ubsan_prologue(&data->location, &flags);
pr_err("calling __builtin_unreachable()\n");
ubsan_epilogue(&flags);
panic("can't return from __builtin_unreachable()");
}
EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
unsigned long val)
{
unsigned long flags;
char val_str[VALUE_LENGTH];
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, &flags);
val_to_string(val_str, sizeof(val_str), data->type, val);
pr_err("load of value %s is not a valid value for type %s\n",
val_str, data->type->type_name);
ubsan_epilogue(&flags);
}
EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);