platform_bionic/libc/malloc_debug/GuardData.cpp
Christopher Ferris 72df6708c8 Fix the default alignment of the allocations.
In order to enforce this constraint:

The pointer returned if the allocation succeeds shall be suitably
aligned so that it may be assigned to a pointer to any type of object
and then used to access such an object in the space allocated.

Force all allocations on 32 bit systems to have 8 byte alignment,
and all allocations on 64 bit systems to have 16 byte alignment.

Add a test to verify that the allocator returns the correct alignments.

Bug: 26739265
Change-Id: I9af53279617408676b94e4ec6481b3ed7ffafc6a
2016-02-12 17:30:30 -08:00

101 lines
3.9 KiB
C++

/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdint.h>
#include <string.h>
#include <vector>
#include "backtrace.h"
#include "Config.h"
#include "debug_disable.h"
#include "debug_log.h"
#include "DebugData.h"
#include "malloc_debug.h"
#include "GuardData.h"
GuardData::GuardData(int init_value, size_t num_bytes) {
// Create a buffer for fast comparisons of the front guard.
cmp_mem_.resize(num_bytes);
memset(cmp_mem_.data(), init_value, cmp_mem_.size());
}
void GuardData::LogFailure(const Header* header, const void* pointer, const void* data) {
ScopedDisableDebugCalls disable;
error_log(LOG_DIVIDER);
error_log("+++ ALLOCATION %p SIZE %zu HAS A CORRUPTED %s GUARD", pointer,
header->real_size(), GetTypeName());
// Log all of the failing bytes.
const uint8_t* expected = cmp_mem_.data();
int pointer_idx = reinterpret_cast<uintptr_t>(data) - reinterpret_cast<uintptr_t>(pointer);
const uint8_t* real = reinterpret_cast<const uint8_t*>(data);
for (size_t i = 0; i < cmp_mem_.size(); i++, pointer_idx++) {
if (real[i] != expected[i]) {
error_log(" pointer[%d] = 0x%02x (expected 0x%02x)", pointer_idx, real[i], expected[i]);
}
}
error_log("Backtrace at time of failure:");
std::vector<uintptr_t> frames(64);
size_t frame_num = backtrace_get(frames.data(), frames.size());
frames.resize(frame_num);
backtrace_log(frames.data(), frames.size());
error_log(LOG_DIVIDER);
}
FrontGuardData::FrontGuardData(const Config& config, size_t* offset)
: GuardData(config.front_guard_value, config.front_guard_bytes) {
// Create a buffer for fast comparisons of the front guard.
cmp_mem_.resize(config.front_guard_bytes);
memset(cmp_mem_.data(), config.front_guard_value, cmp_mem_.size());
// Assumes that front_bytes is a multiple of MINIMUM_ALIGNMENT_BYTES.
offset_ = *offset;
*offset += config.front_guard_bytes;
}
bool FrontGuardData::Valid(DebugData& debug, const Header* header) {
return GuardData::Valid(debug.GetFrontGuard(header));
}
void FrontGuardData::LogFailure(DebugData& debug, const Header* header) {
GuardData::LogFailure(header, debug.GetPointer(header), debug.GetFrontGuard(header));
}
RearGuardData::RearGuardData(const Config& config)
: GuardData(config.rear_guard_value, config.rear_guard_bytes) {
}
bool RearGuardData::Valid(DebugData& debug, const Header* header) {
return GuardData::Valid(debug.GetRearGuard(header));
}
void RearGuardData::LogFailure(DebugData& debug, const Header* header) {
GuardData::LogFailure(header, debug.GetPointer(header), debug.GetRearGuard(header));
}