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Heap protect (#747)

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Setting configENABLE_HEAP_PROTECTOR to 1 obfuscates heap
block pointers by XORing them with an application supplied
canary value. This obfuscation helps to catch heap corruption
should a heap buffer overflow occur.

This PR also adds heap bounds checking to heap_4 and heap_5.

This PR also adds some additional integer underflow checks.
This commit is contained in:
oliverlavery 2023-08-23 05:57:54 +01:00 committed by GitHub
parent b9f488a713
commit 0d9649ca45
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 201 additions and 53 deletions
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4
include/FreeRTOS.h
View file

@ -1071,6 +1071,10 @@
#define configAPPLICATION_ALLOCATED_HEAP 0 #define configAPPLICATION_ALLOCATED_HEAP 0
#endif #endif
#ifndef configENABLE_HEAP_PROTECTOR
#define configENABLE_HEAP_PROTECTOR 0
#endif
#ifndef configUSE_TASK_NOTIFICATIONS #ifndef configUSE_TASK_NOTIFICATIONS
#define configUSE_TASK_NOTIFICATIONS 1 #define configUSE_TASK_NOTIFICATIONS 1
#endif #endif

97
portable/MemMang/heap_4.c
View file

@ -65,10 +65,13 @@
#define heapSIZE_MAX ( ~( ( size_t ) 0 ) ) #define heapSIZE_MAX ( ~( ( size_t ) 0 ) )
/* Check if multiplying a and b will result in overflow. */ /* Check if multiplying a and b will result in overflow. */
#define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) ) #define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) )
/* Check if adding a and b will result in overflow. */ /* Check if adding a and b will result in overflow. */
#define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) ) #define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) )
/* Check if the subtraction operation ( a - b ) will result in underflow. */
#define heapSUBTRACT_WILL_UNDERFLOW( a, b ) ( ( a ) < ( b ) )
/* MSB of the xBlockSize member of an BlockLink_t structure is used to track /* MSB of the xBlockSize member of an BlockLink_t structure is used to track
* the allocation status of a block. When MSB of the xBlockSize member of * the allocation status of a block. When MSB of the xBlockSize member of
@ -100,6 +103,38 @@ typedef struct A_BLOCK_LINK
size_t xBlockSize; /**< The size of the free block. */ size_t xBlockSize; /**< The size of the free block. */
} BlockLink_t; } BlockLink_t;
/* Setting configENABLE_HEAP_PROTECTOR to 1 enables heap block pointers
* protection using an application supplied canary value to catch heap
* corruption should a heap buffer overflow occur.
*/
#if ( configENABLE_HEAP_PROTECTOR == 1 )
/**
* @brief Application provided function to get a random value to be used as canary.
*
* @param pxHeapCanary [out] Output parameter to return the canary value.
*/
extern void vApplicationGetRandomHeapCanary( portPOINTER_SIZE_TYPE * pxHeapCanary );
/* Canary value for protecting internal heap pointers. */
PRIVILEGED_DATA static portPOINTER_SIZE_TYPE xHeapCanary;
/* Macro to load/store BlockLink_t pointers to memory. By XORing the
* pointers with a random canary value, heap overflows will result
* in randomly unpredictable pointer values which will be caught by
* heapVALIDATE_BLOCK_POINTER assert. */
#define heapPROTECT_BLOCK_POINTER( pxBlock ) ( ( BlockLink_t * ) ( ( ( portPOINTER_SIZE_TYPE ) ( pxBlock ) ) ^ xHeapCanary ) )
#else
#define heapPROTECT_BLOCK_POINTER( pxBlock ) ( pxBlock )
#endif /* configENABLE_HEAP_PROTECTOR */
/* Assert that a heap block pointer is within the heap bounds. */
#define heapVALIDATE_BLOCK_POINTER( pxBlock ) \
configASSERT( ( ( uint8_t * ) ( pxBlock ) >= &( ucHeap[ 0 ] ) ) && \
( ( uint8_t * ) ( pxBlock ) <= &( ucHeap[ configTOTAL_HEAP_SIZE - 1 ] ) ) )
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
/* /*
@ -206,12 +241,14 @@ void * pvPortMalloc( size_t xWantedSize )
/* Traverse the list from the start (lowest address) block until /* Traverse the list from the start (lowest address) block until
* one of adequate size is found. */ * one of adequate size is found. */
pxPreviousBlock = &xStart; pxPreviousBlock = &xStart;
pxBlock = xStart.pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( xStart.pxNextFreeBlock );
heapVALIDATE_BLOCK_POINTER( pxBlock );
while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) ) while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != heapPROTECT_BLOCK_POINTER( NULL ) ) )
{ {
pxPreviousBlock = pxBlock; pxPreviousBlock = pxBlock;
pxBlock = pxBlock->pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( pxBlock->pxNextFreeBlock );
heapVALIDATE_BLOCK_POINTER( pxBlock );
} }
/* If the end marker was reached then a block of adequate size /* If the end marker was reached then a block of adequate size
@ -220,7 +257,8 @@ void * pvPortMalloc( size_t xWantedSize )
{ {
/* Return the memory space pointed to - jumping over the /* Return the memory space pointed to - jumping over the
* BlockLink_t structure at its start. */ * BlockLink_t structure at its start. */
pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize ); pvReturn = ( void * ) ( ( ( uint8_t * ) heapPROTECT_BLOCK_POINTER( pxPreviousBlock->pxNextFreeBlock ) ) + xHeapStructSize );
heapVALIDATE_BLOCK_POINTER( pvReturn );
/* This block is being returned for use so must be taken out /* This block is being returned for use so must be taken out
* of the list of free blocks. */ * of the list of free blocks. */
@ -228,6 +266,8 @@ void * pvPortMalloc( size_t xWantedSize )
/* If the block is larger than required it can be split into /* If the block is larger than required it can be split into
* two. */ * two. */
configASSERT( heapSUBTRACT_WILL_UNDERFLOW( pxBlock->xBlockSize, xWantedSize ) == 0 );
if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE ) if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )
{ {
/* This block is to be split into two. Create a new /* This block is to be split into two. Create a new
@ -244,7 +284,7 @@ void * pvPortMalloc( size_t xWantedSize )
/* Insert the new block into the list of free blocks. */ /* Insert the new block into the list of free blocks. */
pxNewBlockLink->pxNextFreeBlock = pxPreviousBlock->pxNextFreeBlock; pxNewBlockLink->pxNextFreeBlock = pxPreviousBlock->pxNextFreeBlock;
pxPreviousBlock->pxNextFreeBlock = pxNewBlockLink; pxPreviousBlock->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxNewBlockLink );
} }
else else
{ {
@ -319,6 +359,7 @@ void vPortFree( void * pv )
/* This casting is to keep the compiler from issuing warnings. */ /* This casting is to keep the compiler from issuing warnings. */
pxLink = ( void * ) puc; pxLink = ( void * ) puc;
heapVALIDATE_BLOCK_POINTER( pxLink );
configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ); configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 );
configASSERT( pxLink->pxNextFreeBlock == NULL ); configASSERT( pxLink->pxNextFreeBlock == NULL );
@ -331,7 +372,12 @@ void vPortFree( void * pv )
heapFREE_BLOCK( pxLink ); heapFREE_BLOCK( pxLink );
#if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 ) #if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 )
{ {
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize ); /* Check for underflow as this can occur if xBlockSize is
* overwritten in a heap block. */
if( heapSUBTRACT_WILL_UNDERFLOW( pxLink->xBlockSize, xHeapStructSize ) == 0 )
{
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
}
} }
#endif #endif
@ -414,9 +460,15 @@ static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
pucAlignedHeap = ( uint8_t * ) uxAddress; pucAlignedHeap = ( uint8_t * ) uxAddress;
#if ( configENABLE_HEAP_PROTECTOR == 1 )
{
vApplicationGetRandomHeapCanary( &( xHeapCanary ) );
}
#endif
/* xStart is used to hold a pointer to the first item in the list of free /* xStart is used to hold a pointer to the first item in the list of free
* blocks. The void cast is used to prevent compiler warnings. */ * blocks. The void cast is used to prevent compiler warnings. */
xStart.pxNextFreeBlock = ( void * ) pucAlignedHeap; xStart.pxNextFreeBlock = ( void * ) heapPROTECT_BLOCK_POINTER( pucAlignedHeap );
xStart.xBlockSize = ( size_t ) 0; xStart.xBlockSize = ( size_t ) 0;
/* pxEnd is used to mark the end of the list of free blocks and is inserted /* pxEnd is used to mark the end of the list of free blocks and is inserted
@ -426,13 +478,13 @@ static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK ); uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
pxEnd = ( BlockLink_t * ) uxAddress; pxEnd = ( BlockLink_t * ) uxAddress;
pxEnd->xBlockSize = 0; pxEnd->xBlockSize = 0;
pxEnd->pxNextFreeBlock = NULL; pxEnd->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( NULL );
/* To start with there is a single free block that is sized to take up the /* To start with there is a single free block that is sized to take up the
* entire heap space, minus the space taken by pxEnd. */ * entire heap space, minus the space taken by pxEnd. */
pxFirstFreeBlock = ( BlockLink_t * ) pucAlignedHeap; pxFirstFreeBlock = ( BlockLink_t * ) pucAlignedHeap;
pxFirstFreeBlock->xBlockSize = ( size_t ) ( uxAddress - ( portPOINTER_SIZE_TYPE ) pxFirstFreeBlock ); pxFirstFreeBlock->xBlockSize = ( size_t ) ( uxAddress - ( portPOINTER_SIZE_TYPE ) pxFirstFreeBlock );
pxFirstFreeBlock->pxNextFreeBlock = pxEnd; pxFirstFreeBlock->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxEnd );
/* Only one block exists - and it covers the entire usable heap space. */ /* Only one block exists - and it covers the entire usable heap space. */
xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize; xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
@ -447,11 +499,16 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVI
/* Iterate through the list until a block is found that has a higher address /* Iterate through the list until a block is found that has a higher address
* than the block being inserted. */ * than the block being inserted. */
for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock ) for( pxIterator = &xStart; heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) < pxBlockToInsert; pxIterator = heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) )
{ {
/* Nothing to do here, just iterate to the right position. */ /* Nothing to do here, just iterate to the right position. */
} }
if( pxIterator != &xStart )
{
heapVALIDATE_BLOCK_POINTER( pxIterator );
}
/* Do the block being inserted, and the block it is being inserted after /* Do the block being inserted, and the block it is being inserted after
* make a contiguous block of memory? */ * make a contiguous block of memory? */
puc = ( uint8_t * ) pxIterator; puc = ( uint8_t * ) pxIterator;
@ -470,17 +527,17 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVI
* make a contiguous block of memory? */ * make a contiguous block of memory? */
puc = ( uint8_t * ) pxBlockToInsert; puc = ( uint8_t * ) pxBlockToInsert;
if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock ) if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) )
{ {
if( pxIterator->pxNextFreeBlock != pxEnd ) if( heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) != pxEnd )
{ {
/* Form one big block from the two blocks. */ /* Form one big block from the two blocks. */
pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize; pxBlockToInsert->xBlockSize += heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock )->xBlockSize;
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock; pxBlockToInsert->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock )->pxNextFreeBlock;
} }
else else
{ {
pxBlockToInsert->pxNextFreeBlock = pxEnd; pxBlockToInsert->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxEnd );
} }
} }
else else
@ -494,7 +551,7 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVI
* to itself. */ * to itself. */
if( pxIterator != pxBlockToInsert ) if( pxIterator != pxBlockToInsert )
{ {
pxIterator->pxNextFreeBlock = pxBlockToInsert; pxIterator->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxBlockToInsert );
} }
else else
{ {
@ -510,7 +567,7 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats )
vTaskSuspendAll(); vTaskSuspendAll();
{ {
pxBlock = xStart.pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( xStart.pxNextFreeBlock );
/* pxBlock will be NULL if the heap has not been initialised. The heap /* pxBlock will be NULL if the heap has not been initialised. The heap
* is initialised automatically when the first allocation is made. */ * is initialised automatically when the first allocation is made. */
@ -534,7 +591,7 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats )
/* Move to the next block in the chain until the last block is /* Move to the next block in the chain until the last block is
* reached. */ * reached. */
pxBlock = pxBlock->pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( pxBlock->pxNextFreeBlock );
} }
} }
} }

153
portable/MemMang/heap_5.c
View file

@ -99,10 +99,13 @@
#define heapSIZE_MAX ( ~( ( size_t ) 0 ) ) #define heapSIZE_MAX ( ~( ( size_t ) 0 ) )
/* Check if multiplying a and b will result in overflow. */ /* Check if multiplying a and b will result in overflow. */
#define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) ) #define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) )
/* Check if adding a and b will result in overflow. */ /* Check if adding a and b will result in overflow. */
#define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) ) #define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) )
/* Check if the subtraction operation ( a - b ) will result in underflow. */
#define heapSUBTRACT_WILL_UNDERFLOW( a, b ) ( ( a ) < ( b ) )
/* MSB of the xBlockSize member of an BlockLink_t structure is used to track /* MSB of the xBlockSize member of an BlockLink_t structure is used to track
* the allocation status of a block. When MSB of the xBlockSize member of * the allocation status of a block. When MSB of the xBlockSize member of
@ -124,6 +127,46 @@ typedef struct A_BLOCK_LINK
size_t xBlockSize; /**< The size of the free block. */ size_t xBlockSize; /**< The size of the free block. */
} BlockLink_t; } BlockLink_t;
/* Setting configENABLE_HEAP_PROTECTOR to 1 enables heap block pointers
* protection using an application supplied canary value to catch heap
* corruption should a heap buffer overflow occur.
*/
#if ( configENABLE_HEAP_PROTECTOR == 1 )
/**
* @brief Application provided function to get a random value to be used as canary.
*
* @param pxHeapCanary [out] Output parameter to return the canary value.
*/
extern void vApplicationGetRandomHeapCanary( portPOINTER_SIZE_TYPE * pxHeapCanary );
/* Canary value for protecting internal heap pointers. */
PRIVILEGED_DATA static portPOINTER_SIZE_TYPE xHeapCanary;
/* Macro to load/store BlockLink_t pointers to memory. By XORing the
* pointers with a random canary value, heap overflows will result
* in randomly unpredictable pointer values which will be caught by
* heapVALIDATE_BLOCK_POINTER assert. */
#define heapPROTECT_BLOCK_POINTER( pxBlock ) ( ( BlockLink_t * ) ( ( ( portPOINTER_SIZE_TYPE ) ( pxBlock ) ) ^ xHeapCanary ) )
#else /* if ( configENABLE_HEAP_PROTECTOR == 1 ) */
#define heapPROTECT_BLOCK_POINTER( pxBlock ) ( pxBlock )
#endif /* configENABLE_HEAP_PROTECTOR */
/* Highest and lowest heap addresses used for heap block bounds checking. */
PRIVILEGED_DATA static uint8_t * pucHeapHighAddress = NULL;
PRIVILEGED_DATA static uint8_t * pucHeapLowAddress = NULL;
/* Assert that a heap block pointer is within the heap bounds. */
#define heapVALIDATE_BLOCK_POINTER( pxBlock ) \
configASSERT( ( pucHeapHighAddress != NULL ) && \
( pucHeapLowAddress != NULL ) && \
( ( uint8_t * ) ( pxBlock ) >= pucHeapLowAddress ) && \
( ( uint8_t * ) ( pxBlock ) < pucHeapHighAddress ) )
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
/* /*
@ -132,8 +175,8 @@ typedef struct A_BLOCK_LINK
* the block in front it and/or the block behind it if the memory blocks are * the block in front it and/or the block behind it if the memory blocks are
* adjacent to each other. * adjacent to each other.
*/ */
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ); static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) PRIVILEGED_FUNCTION;
void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions ) PRIVILEGED_FUNCTION;
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
/* The size of the structure placed at the beginning of each allocated memory /* The size of the structure placed at the beginning of each allocated memory
@ -141,15 +184,15 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert );
static const size_t xHeapStructSize = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK ); static const size_t xHeapStructSize = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
/* Create a couple of list links to mark the start and end of the list. */ /* Create a couple of list links to mark the start and end of the list. */
static BlockLink_t xStart; PRIVILEGED_DATA static BlockLink_t xStart;
static BlockLink_t * pxEnd = NULL; PRIVILEGED_DATA static BlockLink_t * pxEnd = NULL;
/* Keeps track of the number of calls to allocate and free memory as well as the /* Keeps track of the number of calls to allocate and free memory as well as the
* number of free bytes remaining, but says nothing about fragmentation. */ * number of free bytes remaining, but says nothing about fragmentation. */
static size_t xFreeBytesRemaining = 0U; PRIVILEGED_DATA static size_t xFreeBytesRemaining = 0U;
static size_t xMinimumEverFreeBytesRemaining = 0U; PRIVILEGED_DATA static size_t xMinimumEverFreeBytesRemaining = 0U;
static size_t xNumberOfSuccessfulAllocations = 0; PRIVILEGED_DATA static size_t xNumberOfSuccessfulAllocations = 0;
static size_t xNumberOfSuccessfulFrees = 0; PRIVILEGED_DATA static size_t xNumberOfSuccessfulFrees = 0;
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
@ -217,12 +260,14 @@ void * pvPortMalloc( size_t xWantedSize )
/* Traverse the list from the start (lowest address) block until /* Traverse the list from the start (lowest address) block until
* one of adequate size is found. */ * one of adequate size is found. */
pxPreviousBlock = &xStart; pxPreviousBlock = &xStart;
pxBlock = xStart.pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( xStart.pxNextFreeBlock );
heapVALIDATE_BLOCK_POINTER( pxBlock );
while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) ) while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != heapPROTECT_BLOCK_POINTER( NULL ) ) )
{ {
pxPreviousBlock = pxBlock; pxPreviousBlock = pxBlock;
pxBlock = pxBlock->pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( pxBlock->pxNextFreeBlock );
heapVALIDATE_BLOCK_POINTER( pxBlock );
} }
/* If the end marker was reached then a block of adequate size /* If the end marker was reached then a block of adequate size
@ -231,7 +276,8 @@ void * pvPortMalloc( size_t xWantedSize )
{ {
/* Return the memory space pointed to - jumping over the /* Return the memory space pointed to - jumping over the
* BlockLink_t structure at its start. */ * BlockLink_t structure at its start. */
pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize ); pvReturn = ( void * ) ( ( ( uint8_t * ) heapPROTECT_BLOCK_POINTER( pxPreviousBlock->pxNextFreeBlock ) ) + xHeapStructSize );
heapVALIDATE_BLOCK_POINTER( pvReturn );
/* This block is being returned for use so must be taken out /* This block is being returned for use so must be taken out
* of the list of free blocks. */ * of the list of free blocks. */
@ -239,6 +285,8 @@ void * pvPortMalloc( size_t xWantedSize )
/* If the block is larger than required it can be split into /* If the block is larger than required it can be split into
* two. */ * two. */
configASSERT( heapSUBTRACT_WILL_UNDERFLOW( pxBlock->xBlockSize, xWantedSize ) == 0 );
if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE ) if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )
{ {
/* This block is to be split into two. Create a new /* This block is to be split into two. Create a new
@ -246,6 +294,7 @@ void * pvPortMalloc( size_t xWantedSize )
* cast is used to prevent byte alignment warnings from the * cast is used to prevent byte alignment warnings from the
* compiler. */ * compiler. */
pxNewBlockLink = ( void * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize ); pxNewBlockLink = ( void * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize );
configASSERT( ( ( ( size_t ) pxNewBlockLink ) & portBYTE_ALIGNMENT_MASK ) == 0 );
/* Calculate the sizes of two blocks split from the /* Calculate the sizes of two blocks split from the
* single block. */ * single block. */
@ -254,7 +303,7 @@ void * pvPortMalloc( size_t xWantedSize )
/* Insert the new block into the list of free blocks. */ /* Insert the new block into the list of free blocks. */
pxNewBlockLink->pxNextFreeBlock = pxPreviousBlock->pxNextFreeBlock; pxNewBlockLink->pxNextFreeBlock = pxPreviousBlock->pxNextFreeBlock;
pxPreviousBlock->pxNextFreeBlock = pxNewBlockLink; pxPreviousBlock->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxNewBlockLink );
} }
else else
{ {
@ -310,6 +359,7 @@ void * pvPortMalloc( size_t xWantedSize )
} }
#endif /* if ( configUSE_MALLOC_FAILED_HOOK == 1 ) */ #endif /* if ( configUSE_MALLOC_FAILED_HOOK == 1 ) */
configASSERT( ( ( ( size_t ) pvReturn ) & ( size_t ) portBYTE_ALIGNMENT_MASK ) == 0 );
return pvReturn; return pvReturn;
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
@ -328,6 +378,7 @@ void vPortFree( void * pv )
/* This casting is to keep the compiler from issuing warnings. */ /* This casting is to keep the compiler from issuing warnings. */
pxLink = ( void * ) puc; pxLink = ( void * ) puc;
heapVALIDATE_BLOCK_POINTER( pxLink );
configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ); configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 );
configASSERT( pxLink->pxNextFreeBlock == NULL ); configASSERT( pxLink->pxNextFreeBlock == NULL );
@ -340,7 +391,12 @@ void vPortFree( void * pv )
heapFREE_BLOCK( pxLink ); heapFREE_BLOCK( pxLink );
#if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 ) #if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 )
{ {
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize ); /* Check for underflow as this can occur if xBlockSize is
* overwritten in a heap block. */
if( heapSUBTRACT_WILL_UNDERFLOW( pxLink->xBlockSize, xHeapStructSize ) == 0 )
{
( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
}
} }
#endif #endif
@ -398,18 +454,23 @@ void * pvPortCalloc( size_t xNum,
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVILEGED_FUNCTION */
{ {
BlockLink_t * pxIterator; BlockLink_t * pxIterator;
uint8_t * puc; uint8_t * puc;
/* Iterate through the list until a block is found that has a higher address /* Iterate through the list until a block is found that has a higher address
* than the block being inserted. */ * than the block being inserted. */
for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock ) for( pxIterator = &xStart; heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) < pxBlockToInsert; pxIterator = heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) )
{ {
/* Nothing to do here, just iterate to the right position. */ /* Nothing to do here, just iterate to the right position. */
} }
if( pxIterator != &xStart )
{
heapVALIDATE_BLOCK_POINTER( pxIterator );
}
/* Do the block being inserted, and the block it is being inserted after /* Do the block being inserted, and the block it is being inserted after
* make a contiguous block of memory? */ * make a contiguous block of memory? */
puc = ( uint8_t * ) pxIterator; puc = ( uint8_t * ) pxIterator;
@ -428,17 +489,17 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert )
* make a contiguous block of memory? */ * make a contiguous block of memory? */
puc = ( uint8_t * ) pxBlockToInsert; puc = ( uint8_t * ) pxBlockToInsert;
if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock ) if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) )
{ {
if( pxIterator->pxNextFreeBlock != pxEnd ) if( heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock ) != pxEnd )
{ {
/* Form one big block from the two blocks. */ /* Form one big block from the two blocks. */
pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize; pxBlockToInsert->xBlockSize += heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock )->xBlockSize;
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock; pxBlockToInsert->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxIterator->pxNextFreeBlock )->pxNextFreeBlock;
} }
else else
{ {
pxBlockToInsert->pxNextFreeBlock = pxEnd; pxBlockToInsert->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxEnd );
} }
} }
else else
@ -446,13 +507,13 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert )
pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock; pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
} }
/* If the block being inserted plugged a gab, so was merged with the block /* If the block being inserted plugged a gap, so was merged with the block
* before and the block after, then it's pxNextFreeBlock pointer will have * before and the block after, then it's pxNextFreeBlock pointer will have
* already been set, and should not be set here as that would make it point * already been set, and should not be set here as that would make it point
* to itself. */ * to itself. */
if( pxIterator != pxBlockToInsert ) if( pxIterator != pxBlockToInsert )
{ {
pxIterator->pxNextFreeBlock = pxBlockToInsert; pxIterator->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxBlockToInsert );
} }
else else
{ {
@ -461,7 +522,7 @@ static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert )
} }
/*-----------------------------------------------------------*/ /*-----------------------------------------------------------*/
void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions ) void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions ) /* PRIVILEGED_FUNCTION */
{ {
BlockLink_t * pxFirstFreeBlockInRegion = NULL; BlockLink_t * pxFirstFreeBlockInRegion = NULL;
BlockLink_t * pxPreviousFreeBlock; BlockLink_t * pxPreviousFreeBlock;
@ -474,6 +535,12 @@ void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions )
/* Can only call once! */ /* Can only call once! */
configASSERT( pxEnd == NULL ); configASSERT( pxEnd == NULL );
#if ( configENABLE_HEAP_PROTECTOR == 1 )
{
vApplicationGetRandomHeapCanary( &( xHeapCanary ) );
}
#endif
pxHeapRegion = &( pxHeapRegions[ xDefinedRegions ] ); pxHeapRegion = &( pxHeapRegions[ xDefinedRegions ] );
while( pxHeapRegion->xSizeInBytes > 0 ) while( pxHeapRegion->xSizeInBytes > 0 )
@ -499,19 +566,29 @@ void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions )
{ {
/* xStart is used to hold a pointer to the first item in the list of /* xStart is used to hold a pointer to the first item in the list of
* free blocks. The void cast is used to prevent compiler warnings. */ * free blocks. The void cast is used to prevent compiler warnings. */
xStart.pxNextFreeBlock = ( BlockLink_t * ) xAlignedHeap; xStart.pxNextFreeBlock = ( BlockLink_t * ) heapPROTECT_BLOCK_POINTER( xAlignedHeap );
xStart.xBlockSize = ( size_t ) 0; xStart.xBlockSize = ( size_t ) 0;
} }
else else
{ {
/* Should only get here if one region has already been added to the /* Should only get here if one region has already been added to the
* heap. */ * heap. */
configASSERT( pxEnd != NULL ); configASSERT( pxEnd != heapPROTECT_BLOCK_POINTER( NULL ) );
/* Check blocks are passed in with increasing start addresses. */ /* Check blocks are passed in with increasing start addresses. */
configASSERT( ( size_t ) xAddress > ( size_t ) pxEnd ); configASSERT( ( size_t ) xAddress > ( size_t ) pxEnd );
} }
#if ( configENABLE_HEAP_PROTECTOR == 1 )
{
if( ( pucHeapLowAddress == NULL ) ||
( ( uint8_t * ) xAlignedHeap < pucHeapLowAddress ) )
{
pucHeapLowAddress = ( uint8_t * ) xAlignedHeap;
}
}
#endif /* configENABLE_HEAP_PROTECTOR */
/* Remember the location of the end marker in the previous region, if /* Remember the location of the end marker in the previous region, if
* any. */ * any. */
pxPreviousFreeBlock = pxEnd; pxPreviousFreeBlock = pxEnd;
@ -523,24 +600,34 @@ void vPortDefineHeapRegions( const HeapRegion_t * const pxHeapRegions )
xAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK ); xAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
pxEnd = ( BlockLink_t * ) xAddress; pxEnd = ( BlockLink_t * ) xAddress;
pxEnd->xBlockSize = 0; pxEnd->xBlockSize = 0;
pxEnd->pxNextFreeBlock = NULL; pxEnd->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( NULL );
/* To start with there is a single free block in this region that is /* To start with there is a single free block in this region that is
* sized to take up the entire heap region minus the space taken by the * sized to take up the entire heap region minus the space taken by the
* free block structure. */ * free block structure. */
pxFirstFreeBlockInRegion = ( BlockLink_t * ) xAlignedHeap; pxFirstFreeBlockInRegion = ( BlockLink_t * ) xAlignedHeap;
pxFirstFreeBlockInRegion->xBlockSize = ( size_t ) ( xAddress - ( portPOINTER_SIZE_TYPE ) pxFirstFreeBlockInRegion ); pxFirstFreeBlockInRegion->xBlockSize = ( size_t ) ( xAddress - ( portPOINTER_SIZE_TYPE ) pxFirstFreeBlockInRegion );
pxFirstFreeBlockInRegion->pxNextFreeBlock = pxEnd; pxFirstFreeBlockInRegion->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxEnd );
/* If this is not the first region that makes up the entire heap space /* If this is not the first region that makes up the entire heap space
* then link the previous region to this region. */ * then link the previous region to this region. */
if( pxPreviousFreeBlock != NULL ) if( pxPreviousFreeBlock != NULL )
{ {
pxPreviousFreeBlock->pxNextFreeBlock = pxFirstFreeBlockInRegion; pxPreviousFreeBlock->pxNextFreeBlock = heapPROTECT_BLOCK_POINTER( pxFirstFreeBlockInRegion );
} }
xTotalHeapSize += pxFirstFreeBlockInRegion->xBlockSize; xTotalHeapSize += pxFirstFreeBlockInRegion->xBlockSize;
#if ( configENABLE_HEAP_PROTECTOR == 1 )
{
if( ( pucHeapHighAddress == NULL ) ||
( ( ( ( uint8_t * ) pxFirstFreeBlockInRegion ) + pxFirstFreeBlockInRegion->xBlockSize ) > pucHeapHighAddress ) )
{
pucHeapHighAddress = ( ( uint8_t * ) pxFirstFreeBlockInRegion ) + pxFirstFreeBlockInRegion->xBlockSize;
}
}
#endif
/* Move onto the next HeapRegion_t structure. */ /* Move onto the next HeapRegion_t structure. */
xDefinedRegions++; xDefinedRegions++;
pxHeapRegion = &( pxHeapRegions[ xDefinedRegions ] ); pxHeapRegion = &( pxHeapRegions[ xDefinedRegions ] );
@ -561,7 +648,7 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats )
vTaskSuspendAll(); vTaskSuspendAll();
{ {
pxBlock = xStart.pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( xStart.pxNextFreeBlock );
/* pxBlock will be NULL if the heap has not been initialised. The heap /* pxBlock will be NULL if the heap has not been initialised. The heap
* is initialised automatically when the first allocation is made. */ * is initialised automatically when the first allocation is made. */
@ -591,7 +678,7 @@ void vPortGetHeapStats( HeapStats_t * pxHeapStats )
/* Move to the next block in the chain until the last block is /* Move to the next block in the chain until the last block is
* reached. */ * reached. */
pxBlock = pxBlock->pxNextFreeBlock; pxBlock = heapPROTECT_BLOCK_POINTER( pxBlock->pxNextFreeBlock );
} }
} }
} }