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395 lines
10 KiB
395 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* UBSAN error reporting functions |
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* |
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* Copyright (c) 2014 Samsung Electronics Co., Ltd. |
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* Author: Andrey Ryabinin <[email protected]> |
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*/ |
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#include <linux/bitops.h> |
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#include <linux/bug.h> |
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#include <linux/ctype.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/types.h> |
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#include <linux/sched.h> |
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#include <linux/uaccess.h> |
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#include <kunit/test-bug.h> |
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#include "ubsan.h" |
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static const char * const type_check_kinds[] = { |
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"load of", |
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"store to", |
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"reference binding to", |
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"member access within", |
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"member call on", |
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"constructor call on", |
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"downcast of", |
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"downcast of" |
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}; |
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#define REPORTED_BIT 31 |
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#if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN) |
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#define COLUMN_MASK (~(1U << REPORTED_BIT)) |
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#define LINE_MASK (~0U) |
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#else |
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#define COLUMN_MASK (~0U) |
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#define LINE_MASK (~(1U << REPORTED_BIT)) |
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#endif |
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#define VALUE_LENGTH 40 |
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static bool was_reported(struct source_location *location) |
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{ |
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return test_and_set_bit(REPORTED_BIT, &location->reported); |
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} |
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static bool suppress_report(struct source_location *loc) |
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{ |
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return current->in_ubsan || was_reported(loc); |
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} |
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static bool type_is_int(struct type_descriptor *type) |
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{ |
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return type->type_kind == type_kind_int; |
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} |
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static bool type_is_signed(struct type_descriptor *type) |
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{ |
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WARN_ON(!type_is_int(type)); |
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return type->type_info & 1; |
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} |
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static unsigned type_bit_width(struct type_descriptor *type) |
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{ |
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return 1 << (type->type_info >> 1); |
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} |
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static bool is_inline_int(struct type_descriptor *type) |
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{ |
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unsigned inline_bits = sizeof(unsigned long)*8; |
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unsigned bits = type_bit_width(type); |
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WARN_ON(!type_is_int(type)); |
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return bits <= inline_bits; |
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} |
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static s_max get_signed_val(struct type_descriptor *type, void *val) |
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{ |
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if (is_inline_int(type)) { |
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unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type); |
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unsigned long ulong_val = (unsigned long)val; |
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return ((s_max)ulong_val) << extra_bits >> extra_bits; |
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} |
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if (type_bit_width(type) == 64) |
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return *(s64 *)val; |
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return *(s_max *)val; |
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} |
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static bool val_is_negative(struct type_descriptor *type, void *val) |
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{ |
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return type_is_signed(type) && get_signed_val(type, val) < 0; |
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} |
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static u_max get_unsigned_val(struct type_descriptor *type, void *val) |
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{ |
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if (is_inline_int(type)) |
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return (unsigned long)val; |
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if (type_bit_width(type) == 64) |
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return *(u64 *)val; |
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return *(u_max *)val; |
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} |
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static void val_to_string(char *str, size_t size, struct type_descriptor *type, |
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void *value) |
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{ |
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if (type_is_int(type)) { |
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if (type_bit_width(type) == 128) { |
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#if defined(CONFIG_ARCH_SUPPORTS_INT128) |
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u_max val = get_unsigned_val(type, value); |
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scnprintf(str, size, "0x%08x%08x%08x%08x", |
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(u32)(val >> 96), |
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(u32)(val >> 64), |
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(u32)(val >> 32), |
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(u32)(val)); |
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#else |
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WARN_ON(1); |
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#endif |
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} else if (type_is_signed(type)) { |
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scnprintf(str, size, "%lld", |
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(s64)get_signed_val(type, value)); |
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} else { |
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scnprintf(str, size, "%llu", |
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(u64)get_unsigned_val(type, value)); |
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} |
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} |
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} |
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static void ubsan_prologue(struct source_location *loc, const char *reason) |
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{ |
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current->in_ubsan++; |
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pr_err("========================================" |
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"========================================\n"); |
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pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name, |
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loc->line & LINE_MASK, loc->column & COLUMN_MASK); |
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kunit_fail_current_test("%s in %s", reason, loc->file_name); |
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} |
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static void ubsan_epilogue(void) |
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{ |
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dump_stack(); |
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pr_err("========================================" |
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"========================================\n"); |
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current->in_ubsan--; |
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if (panic_on_warn) { |
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/* |
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* This thread may hit another WARN() in the panic path. |
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* Resetting this prevents additional WARN() from panicking the |
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* system on this thread. Other threads are blocked by the |
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* panic_mutex in panic(). |
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*/ |
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panic_on_warn = 0; |
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panic("panic_on_warn set ...\n"); |
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} |
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} |
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void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs) |
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{ |
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struct overflow_data *data = _data; |
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char rhs_val_str[VALUE_LENGTH]; |
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if (suppress_report(&data->location)) |
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return; |
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ubsan_prologue(&data->location, "division-overflow"); |
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val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs); |
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if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1) |
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pr_err("division of %s by -1 cannot be represented in type %s\n", |
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rhs_val_str, data->type->type_name); |
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else |
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pr_err("division by zero\n"); |
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ubsan_epilogue(); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); |
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static void handle_null_ptr_deref(struct type_mismatch_data_common *data) |
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{ |
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if (suppress_report(data->location)) |
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return; |
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ubsan_prologue(data->location, "null-ptr-deref"); |
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pr_err("%s null pointer of type %s\n", |
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type_check_kinds[data->type_check_kind], |
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data->type->type_name); |
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ubsan_epilogue(); |
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} |
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static void handle_misaligned_access(struct type_mismatch_data_common *data, |
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unsigned long ptr) |
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{ |
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if (suppress_report(data->location)) |
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return; |
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ubsan_prologue(data->location, "misaligned-access"); |
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pr_err("%s misaligned address %p for type %s\n", |
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type_check_kinds[data->type_check_kind], |
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(void *)ptr, data->type->type_name); |
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pr_err("which requires %ld byte alignment\n", data->alignment); |
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ubsan_epilogue(); |
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} |
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static void handle_object_size_mismatch(struct type_mismatch_data_common *data, |
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unsigned long ptr) |
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{ |
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if (suppress_report(data->location)) |
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return; |
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ubsan_prologue(data->location, "object-size-mismatch"); |
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pr_err("%s address %p with insufficient space\n", |
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type_check_kinds[data->type_check_kind], |
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(void *) ptr); |
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pr_err("for an object of type %s\n", data->type->type_name); |
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ubsan_epilogue(); |
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} |
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static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data, |
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unsigned long ptr) |
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{ |
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unsigned long flags = user_access_save(); |
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if (!ptr) |
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handle_null_ptr_deref(data); |
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else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) |
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handle_misaligned_access(data, ptr); |
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else |
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handle_object_size_mismatch(data, ptr); |
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user_access_restore(flags); |
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} |
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void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, |
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void *ptr) |
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{ |
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struct type_mismatch_data_common common_data = { |
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.location = &data->location, |
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.type = data->type, |
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.alignment = data->alignment, |
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.type_check_kind = data->type_check_kind |
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}; |
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ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_type_mismatch); |
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void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr) |
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{ |
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struct type_mismatch_data_v1 *data = _data; |
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struct type_mismatch_data_common common_data = { |
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.location = &data->location, |
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.type = data->type, |
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.alignment = 1UL << data->log_alignment, |
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.type_check_kind = data->type_check_kind |
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}; |
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ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1); |
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void __ubsan_handle_out_of_bounds(void *_data, void *index) |
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{ |
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struct out_of_bounds_data *data = _data; |
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char index_str[VALUE_LENGTH]; |
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if (suppress_report(&data->location)) |
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return; |
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ubsan_prologue(&data->location, "array-index-out-of-bounds"); |
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val_to_string(index_str, sizeof(index_str), data->index_type, index); |
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pr_err("index %s is out of range for type %s\n", index_str, |
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data->array_type->type_name); |
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ubsan_epilogue(); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); |
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void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs) |
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{ |
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struct shift_out_of_bounds_data *data = _data; |
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struct type_descriptor *rhs_type = data->rhs_type; |
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struct type_descriptor *lhs_type = data->lhs_type; |
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char rhs_str[VALUE_LENGTH]; |
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char lhs_str[VALUE_LENGTH]; |
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unsigned long ua_flags = user_access_save(); |
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if (suppress_report(&data->location)) |
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goto out; |
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ubsan_prologue(&data->location, "shift-out-of-bounds"); |
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val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); |
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val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); |
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if (val_is_negative(rhs_type, rhs)) |
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pr_err("shift exponent %s is negative\n", rhs_str); |
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else if (get_unsigned_val(rhs_type, rhs) >= |
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type_bit_width(lhs_type)) |
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pr_err("shift exponent %s is too large for %u-bit type %s\n", |
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rhs_str, |
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type_bit_width(lhs_type), |
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lhs_type->type_name); |
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else if (val_is_negative(lhs_type, lhs)) |
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pr_err("left shift of negative value %s\n", |
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lhs_str); |
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else |
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pr_err("left shift of %s by %s places cannot be" |
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" represented in type %s\n", |
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lhs_str, rhs_str, |
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lhs_type->type_name); |
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ubsan_epilogue(); |
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out: |
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user_access_restore(ua_flags); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); |
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void __ubsan_handle_builtin_unreachable(void *_data) |
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{ |
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struct unreachable_data *data = _data; |
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ubsan_prologue(&data->location, "unreachable"); |
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pr_err("calling __builtin_unreachable()\n"); |
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ubsan_epilogue(); |
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panic("can't return from __builtin_unreachable()"); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable); |
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void __ubsan_handle_load_invalid_value(void *_data, void *val) |
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{ |
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struct invalid_value_data *data = _data; |
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char val_str[VALUE_LENGTH]; |
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if (suppress_report(&data->location)) |
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return; |
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ubsan_prologue(&data->location, "invalid-load"); |
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val_to_string(val_str, sizeof(val_str), data->type, val); |
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pr_err("load of value %s is not a valid value for type %s\n", |
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val_str, data->type->type_name); |
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ubsan_epilogue(); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); |
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void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, |
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unsigned long align, |
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unsigned long offset); |
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void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, |
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unsigned long align, |
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unsigned long offset) |
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{ |
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struct alignment_assumption_data *data = _data; |
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unsigned long real_ptr; |
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if (suppress_report(&data->location)) |
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return; |
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ubsan_prologue(&data->location, "alignment-assumption"); |
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if (offset) |
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pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed", |
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align, offset, data->type->type_name); |
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else |
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pr_err("assumption of %lu byte alignment for pointer of type %s failed", |
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align, data->type->type_name); |
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real_ptr = ptr - offset; |
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pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes", |
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offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0), |
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real_ptr & (align - 1)); |
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ubsan_epilogue(); |
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} |
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EXPORT_SYMBOL(__ubsan_handle_alignment_assumption);
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