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https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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101 lines
3.9 KiB
C
101 lines
3.9 KiB
C
/*
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* FreeRTOS memory safety proofs with CBMC.
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* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* http://aws.amazon.com/freertos
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* http://www.FreeRTOS.org
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*/
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#include <stdint.h>
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/* FreeRTOS includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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/* FreeRTOS+TCP includes. */
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#include "FreeRTOS_IP.h"
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#include "FreeRTOS_IP_Private.h"
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#include "FreeRTOS_DHCP.h"
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/*
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* CBMC automatically unwinds strlen on a fixed string
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*/
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const char * pcApplicationHostnameHook(void) {
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return "hostname";
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}
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/*
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* This stub allows us to overcome the unwinding error obtained
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* in the do-while loop within function prvCreatePartDHCPMessage.
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* The behaviour is similar to the original function, but failed allocations
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* are not considered here (this is a safe assumption that avoids the error)
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*/
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void *FreeRTOS_GetUDPPayloadBuffer( size_t xRequestedSizeBytes, TickType_t xBlockTimeTicks )
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{
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NetworkBufferDescriptor_t xNetworkBuffer;
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void *pvReturn;
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xNetworkBuffer.xDataLength = ipUDP_PAYLOAD_OFFSET_IPv4 + xRequestedSizeBytes;
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xNetworkBuffer.pucEthernetBuffer = malloc( xNetworkBuffer.xDataLength );
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pvReturn = (void *) &( xNetworkBuffer.pucEthernetBuffer[ ipUDP_PAYLOAD_OFFSET_IPv4 ] );
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return pvReturn;
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}
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/*
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* We stub out FreeRTOS_recvfrom to do nothing but return a buffer of
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* arbitrary size (but size at most BUFFER_SIZE) containing arbitrary
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* data. We need to bound the size of the buffer in order to bound
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* the number of iterations of the loop prvProcessDHCPReplies.0 that
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* iterates over the buffer contents. The bound BUFFER_SIZE is chosen
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* to be large enough to ensure complete code coverage, and small
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* enough to ensure CBMC terminates within a reasonable amount of
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* time.
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*/
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int32_t FreeRTOS_recvfrom(
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Socket_t xSocket, void *pvBuffer, size_t xBufferLength,
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BaseType_t xFlags, struct freertos_sockaddr *pxSourceAddress,
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socklen_t *pxSourceAddressLength )
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{
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__CPROVER_assert(xFlags & FREERTOS_ZERO_COPY, "I can only do ZERO_COPY");
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size_t xBufferSize;
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/* A DHCP message (min. size 241B) is preceded by the IP buffer padding (10B) and the UDP payload (42B) */
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__CPROVER_assume(xBufferSize >= ipBUFFER_PADDING + ipUDP_PAYLOAD_OFFSET_IPv4);
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/* The last field of a DHCP message (Options) is variable in length, but 6 additional bytes are enough */
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/* to obtain maximum coverage with this proof. Hence, we have BUFFER_SIZE=299 */
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__CPROVER_assume(xBufferSize <= BUFFER_SIZE);
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/* The buffer gets allocated and we set the pointer past the UDP payload (i.e., start of DHCP message) */
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*((char **)pvBuffer) = malloc(xBufferSize) + ipBUFFER_PADDING + ipUDP_PAYLOAD_OFFSET_IPv4;
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return xBufferSize - ipUDP_PAYLOAD_OFFSET_IPv4 - ipBUFFER_PADDING;
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}
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/*
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* The harness test proceeds to call DHCPProcess with an unconstrained value
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*/
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void harness()
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{
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BaseType_t xReset;
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vDHCPProcess( xReset );
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}
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