From 8eb35852523b924a3a2e3a38668bacbb4b494ea5 Mon Sep 17 00:00:00 2001 From: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com> Date: Mon, 28 Feb 2022 11:59:00 -0800 Subject: [PATCH] Move MSB check after final size calculation (#463) We use the MSB of the size member of a BlockLink_t to track whether not a block is allocated. Consequently, the size must not be so large that the MSB is set. The check to see if the MSB in the size is set needs to be done after the final size (metadata + alignment) is calculated. Signed-off-by: Gaurav Aggarwal --- portable/MemMang/heap_2.c | 48 +++++++++++++++++----------------- portable/MemMang/heap_4.c | 55 +++++++++++++++++++-------------------- portable/MemMang/heap_5.c | 54 +++++++++++++++++++------------------- 3 files changed, 78 insertions(+), 79 deletions(-) diff --git a/portable/MemMang/heap_2.c b/portable/MemMang/heap_2.c index 85ebdf2e4..f50965ef5 100644 --- a/portable/MemMang/heap_2.c +++ b/portable/MemMang/heap_2.c @@ -160,36 +160,36 @@ void * pvPortMalloc( size_t xWantedSize ) xHeapHasBeenInitialised = pdTRUE; } - /* Check the requested block size is not so large that the top bit is - * set. The top bit of the block size member of the BlockLink_t structure - * is used to determine who owns the block - the application or the - * kernel, so it must be free. */ - if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) ) + /* The wanted size must be increased so it can contain a BlockLink_t + * structure in addition to the requested amount of bytes. */ + if( ( xWantedSize > 0 ) && + ( ( xWantedSize + heapSTRUCT_SIZE ) > xWantedSize ) ) /* Overflow check. */ { - /* The wanted size must be increased so it can contain a BlockLink_t - * structure in addition to the requested amount of bytes. */ - if( ( xWantedSize > 0 ) && - ( ( xWantedSize + heapSTRUCT_SIZE ) > xWantedSize ) ) /* Overflow check */ - { - xWantedSize += heapSTRUCT_SIZE; + xWantedSize += heapSTRUCT_SIZE; - /* Byte alignment required. Check for overflow. */ - if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) - > xWantedSize ) - { - xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); - configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 ); - } - else - { - xWantedSize = 0; - } + /* Byte alignment required. Check for overflow. */ + if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) + > xWantedSize ) + { + xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); + configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 ); } else { xWantedSize = 0; } + } + else + { + xWantedSize = 0; + } + /* Check the block size we are trying to allocate is not so large that the + * top bit is set. The top bit of the block size member of the BlockLink_t + * structure is used to determine who owns the block - the application or + * the kernel, so it must be free. */ + if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) != 0 ) + { if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) ) { /* Blocks are stored in byte order - traverse the list from the start @@ -274,10 +274,10 @@ void vPortFree( void * pv ) * byte alignment warnings. */ pxLink = ( void * ) puc; - configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) ); + configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ); configASSERT( pxLink->pxNextFreeBlock == NULL ); - if( heapBLOCK_IS_ALLOCATED( pxLink ) ) + if( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ) { if( pxLink->pxNextFreeBlock == NULL ) { diff --git a/portable/MemMang/heap_4.c b/portable/MemMang/heap_4.c index 2ef538106..28efcbbca 100644 --- a/portable/MemMang/heap_4.c +++ b/portable/MemMang/heap_4.c @@ -146,44 +146,43 @@ void * pvPortMalloc( size_t xWantedSize ) mtCOVERAGE_TEST_MARKER(); } - /* Check the requested block size is not so large that the top bit is - * set. The top bit of the block size member of the BlockLink_t structure - * is used to determine who owns the block - the application or the - * kernel, so it must be free. */ - if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) ) + /* The wanted size must be increased so it can contain a BlockLink_t + * structure in addition to the requested amount of bytes. */ + if( ( xWantedSize > 0 ) && + ( ( xWantedSize + xHeapStructSize ) > xWantedSize ) ) /* Overflow check. */ { - /* The wanted size must be increased so it can contain a BlockLink_t - * structure in addition to the requested amount of bytes. */ - if( ( xWantedSize > 0 ) && - ( ( xWantedSize + xHeapStructSize ) > xWantedSize ) ) /* Overflow check */ - { - xWantedSize += xHeapStructSize; + xWantedSize += xHeapStructSize; - /* Ensure that blocks are always aligned. */ - if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 ) + /* Ensure that blocks are always aligned. */ + if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 ) + { + /* Byte alignment required. Check for overflow. */ + if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) > xWantedSize ) { - /* Byte alignment required. Check for overflow. */ - if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) - > xWantedSize ) - { - xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); - configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 ); - } - else - { - xWantedSize = 0; - } + xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); + configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 ); } else { - mtCOVERAGE_TEST_MARKER(); + xWantedSize = 0; } } else { - xWantedSize = 0; + mtCOVERAGE_TEST_MARKER(); } + } + else + { + xWantedSize = 0; + } + /* Check the block size we are trying to allocate is not so large that the + * top bit is set. The top bit of the block size member of the BlockLink_t + * structure is used to determine who owns the block - the application or + * the kernel, so it must be free. */ + if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) != 0 ) + { if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) ) { /* Traverse the list from the start (lowest address) block until @@ -302,10 +301,10 @@ void vPortFree( void * pv ) /* This casting is to keep the compiler from issuing warnings. */ pxLink = ( void * ) puc; - configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) ); + configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ); configASSERT( pxLink->pxNextFreeBlock == NULL ); - if( heapBLOCK_IS_ALLOCATED( pxLink ) ) + if( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ) { if( pxLink->pxNextFreeBlock == NULL ) { diff --git a/portable/MemMang/heap_5.c b/portable/MemMang/heap_5.c index c12c95689..c0c4ea4c3 100644 --- a/portable/MemMang/heap_5.c +++ b/portable/MemMang/heap_5.c @@ -157,43 +157,43 @@ void * pvPortMalloc( size_t xWantedSize ) vTaskSuspendAll(); { - /* Check the requested block size is not so large that the top bit is - * set. The top bit of the block size member of the BlockLink_t structure - * is used to determine who owns the block - the application or the - * kernel, so it must be free. */ - if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) ) + /* The wanted size is increased so it can contain a BlockLink_t + * structure in addition to the requested amount of bytes. */ + if( ( xWantedSize > 0 ) && + ( ( xWantedSize + xHeapStructSize ) > xWantedSize ) ) /* Overflow check. */ { - /* The wanted size is increased so it can contain a BlockLink_t - * structure in addition to the requested amount of bytes. */ - if( ( xWantedSize > 0 ) && - ( ( xWantedSize + xHeapStructSize ) > xWantedSize ) ) /* Overflow check */ - { - xWantedSize += xHeapStructSize; + xWantedSize += xHeapStructSize; - /* Ensure that blocks are always aligned */ - if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 ) + /* Ensure that blocks are always aligned */ + if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 ) + { + /* Byte alignment required. Check for overflow */ + if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) > + xWantedSize ) { - /* Byte alignment required. Check for overflow */ - if( ( xWantedSize + ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ) ) > - xWantedSize ) - { - xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); - } - else - { - xWantedSize = 0; - } + xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) ); } else { - mtCOVERAGE_TEST_MARKER(); + xWantedSize = 0; } } else { - xWantedSize = 0; + mtCOVERAGE_TEST_MARKER(); } + } + else + { + xWantedSize = 0; + } + /* Check the block size we are trying to allocate is not so large that the + * top bit is set. The top bit of the block size member of the BlockLink_t + * structure is used to determine who owns the block - the application or + * the kernel, so it must be free. */ + if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) != 0 ) + { if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) ) { /* Traverse the list from the start (lowest address) block until @@ -310,10 +310,10 @@ void vPortFree( void * pv ) /* This casting is to keep the compiler from issuing warnings. */ pxLink = ( void * ) puc; - configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) ); + configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ); configASSERT( pxLink->pxNextFreeBlock == NULL ); - if( heapBLOCK_IS_ALLOCATED( pxLink ) ) + if( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 ) { if( pxLink->pxNextFreeBlock == NULL ) {