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Commit 0cc9a6e6 authored by Sergio Giro's avatar Sergio Giro
Browse files

libutils: fix overflow in SharedBuffer [DO NOT MERGE] 

See
https://code.google.com/p/android/issues/detail?id=181910

Bug: 22952485
(cherry picked from commit 66b6eb94)

Change-Id: Ic71dd0025b9a7588c4f3bb1c7be1bd13d2ff5105
parent ca15dfd0

libutils/Android.mk

+13 −0
Original line number Diff line number Diff line
@@ -125,6 +125,19 @@ include $(BUILD_SHARED_LIBRARY) 


# Include subdirectory makefiles

# ============================================================

include $(CLEAR_VARS)

LOCAL_MODULE := SharedBufferTest

LOCAL_STATIC_LIBRARIES := libutils libcutils

LOCAL_SHARED_LIBRARIES := liblog

LOCAL_SRC_FILES := SharedBufferTest.cpp

include $(BUILD_NATIVE_TEST)



include $(CLEAR_VARS)

LOCAL_MODULE := SharedBufferTest

LOCAL_STATIC_LIBRARIES := libutils libcutils

LOCAL_SHARED_LIBRARIES := liblog

LOCAL_SRC_FILES := SharedBufferTest.cpp

include $(BUILD_HOST_NATIVE_TEST)



# If we're building with ONE_SHOT_MAKEFILE (mm, mmm), then what the framework

# team really wants is to build the stuff defined by this makefile.

libutils/SharedBuffer.cpp

+14 −1
Original line number Diff line number Diff line
@@ -14,9 +14,12 @@ 
 * limitations under the License.

 */



#define __STDC_LIMIT_MACROS

#include <stdint.h>

#include <stdlib.h>

#include <string.h>



#include <log/log.h>

#include <utils/SharedBuffer.h>

#include <utils/Atomic.h>
@@ -26,6 +29,11 @@ namespace android { 


SharedBuffer* SharedBuffer::alloc(size_t size)

{

    // Don't overflow if the combined size of the buffer / header is larger than

    // size_max.

    LOG_ALWAYS_FATAL_IF((size >= (SIZE_MAX - sizeof(SharedBuffer))),

                        "Invalid buffer size %zu", size);



    SharedBuffer* sb = static_cast<SharedBuffer *>(malloc(sizeof(SharedBuffer) + size));

    if (sb) {

        sb->mRefs = 1;
@@ -60,6 +68,11 @@ SharedBuffer* SharedBuffer::editResize(size_t newSize) const 
    if (onlyOwner()) {

        SharedBuffer* buf = const_cast<SharedBuffer*>(this);

        if (buf->mSize == newSize) return buf;

        // Don't overflow if the combined size of the new buffer / header is larger than

        // size_max.

        LOG_ALWAYS_FATAL_IF((newSize >= (SIZE_MAX - sizeof(SharedBuffer))),

                            "Invalid buffer size %zu", newSize);



        buf = (SharedBuffer*)realloc(buf, sizeof(SharedBuffer) + newSize);

        if (buf != NULL) {

            buf->mSize = newSize;

libutils/SharedBufferTest.cpp

0 → 100644
+58 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2015 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */



#define __STDC_LIMIT_MACROS



#include <utils/SharedBuffer.h>



#include <gtest/gtest.h>



#include <memory>

#include <stdint.h>



TEST(SharedBufferTest, TestAlloc) {

  EXPECT_DEATH(android::SharedBuffer::alloc(SIZE_MAX), "");

  EXPECT_DEATH(android::SharedBuffer::alloc(SIZE_MAX - sizeof(android::SharedBuffer)), "");



  // Make sure we don't die here.

  // Check that null is returned, as we are asking for the whole address space.

  android::SharedBuffer* buf =

      android::SharedBuffer::alloc(SIZE_MAX - sizeof(android::SharedBuffer) - 1);

  ASSERT_TRUE(NULL == buf);



  buf = android::SharedBuffer::alloc(0);

  ASSERT_FALSE(NULL == buf);

  ASSERT_EQ(0U, buf->size());

  buf->release();

}



TEST(SharedBufferTest, TestEditResize) {

  android::SharedBuffer* buf = android::SharedBuffer::alloc(10);

  EXPECT_DEATH(buf->editResize(SIZE_MAX - sizeof(android::SharedBuffer)), "");

  buf = android::SharedBuffer::alloc(10);

  EXPECT_DEATH(buf->editResize(SIZE_MAX), "");



  buf = android::SharedBuffer::alloc(10);

  // Make sure we don't die here.

  // Check that null is returned, as we are asking for the whole address space.

  buf = buf->editResize(SIZE_MAX - sizeof(android::SharedBuffer) - 1);

  ASSERT_TRUE(NULL == buf);



  buf = android::SharedBuffer::alloc(10);

  buf = buf->editResize(0);

  ASSERT_EQ(0U, buf->size());

  buf->release();

}