text: /* TEMPLATE GENERATED TESTCASE FILE
  Filename: CWE123_Write_What_Where_Condition__listen_socket_02.c
  Label Definition File: CWE123_Write_What_Where_Condition.label.xml
  Template File: sources-sink-02.tmpl.c
  */
  /*
   * @description
   * CWE: 123 Write-What-Where Condition
   * BadSource: listen_socket Overwrite linked list pointers using a listen socket (server side)
   * GoodSource: Don't overwrite linked list pointers
   * Sink:
   *    BadSink : Remove element from list
   * Flow Variant: 02 Control flow: if(1) and if(0)
   *
   * */
  
  #include "std_testcase.h"
  
  typedef struct _linkedList
  {
      struct _linkedList *next;
      struct _linkedList *prev;
  } linkedList;
  
  typedef struct _badStruct
  {
      linkedList list;
  } badStruct;
  
  static linkedList *linkedListPrev, *linkedListNext;
  
  #ifdef _WIN32
  #include <winsock2.h>
  #include <windows.h>
  #include <direct.h>
  #pragma comment(lib, "ws2_32") /* include ws2_32.lib when linking */
  #define CLOSE_SOCKET closesocket
  #else
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netinet/in.h>
  #include <arpa/inet.h>
  #include <unistd.h>
  #define INVALID_SOCKET -1
  #define SOCKET_ERROR -1
  #define CLOSE_SOCKET close
  #define SOCKET int
  #endif
  
  #define TCP_PORT 27015
  #define LISTEN_BACKLOG 5
  
  #ifndef OMITBAD
  
  void CWE123_Write_What_Where_Condition__listen_socket_02_bad()
  {
      badStruct data;
      linkedList head = { &head, &head };
      /* This simulates a Microsoft-style linked list insertion */
      data.list.next = head.next;
      data.list.prev = head.prev;
      head.next = &data.list;
      head.prev = &data.list;
      if(1)
      {
          {
  #ifdef _WIN32
              WSADATA wsaData;
              int wsaDataInit = 0;
  #endif
              int recvResult;
              struct sockaddr_in service;
              SOCKET listenSocket = INVALID_SOCKET;
              SOCKET acceptSocket = INVALID_SOCKET;
              do
              {
  #ifdef _WIN32
                  if (WSAStartup(MAKEWORD(2,2), &wsaData) != NO_ERROR)
                  {
                      break;
                  }
                  wsaDataInit = 1;
  #endif
                  listenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
                  if (listenSocket == INVALID_SOCKET)
                  {
                      break;
                  }
                  memset(&service, 0, sizeof(service));
                  service.sin_family = AF_INET;
                  service.sin_addr.s_addr = INADDR_ANY;
                  service.sin_port = htons(TCP_PORT);
                  if (bind(listenSocket, (struct sockaddr*)&service, sizeof(service)) == SOCKET_ERROR)
                  {
                      break;
                  }
                  if (listen(listenSocket, LISTEN_BACKLOG) == SOCKET_ERROR)
                  {
                      break;
                  }
                  acceptSocket = accept(listenSocket, NULL, NULL);
                  if (acceptSocket == SOCKET_ERROR)
                  {
                      break;
                  }
                  /* Abort on error or the connection was closed */
                  /* FLAW: overwrite linked list pointers with data */
                  recvResult = recv(acceptSocket, (char*)&data, sizeof(data), 0);
                  if (recvResult == SOCKET_ERROR || recvResult == 0)
                  {
                      break;
                  }
              }
              while (0);
              if (listenSocket != INVALID_SOCKET)
              {
                  CLOSE_SOCKET(listenSocket);
              }
              if (acceptSocket != INVALID_SOCKET)
              {
                  CLOSE_SOCKET(acceptSocket);
              }
  #ifdef _WIN32
              if (wsaDataInit)
              {
                  WSACleanup();
              }
  #endif
          }
      }
      /* POTENTIAL FLAW: The following removes 'a' from the list.  Because of the possible overflow this
       * causes a "write-what-where" aka "write4".  It does another write as
       * well.  But this is the prototypical "write-what-where" at least from
       * the Windows perspective.
       *
       * linkedListPrev = a->list->prev  WHAT
       * linkedListNext = a->list->next  WHERE
       * linkedListPrev->next = linkedListNext  "at the address that prev/WHERE points, write
       *                    next/WHAT"
       *                    aka "write-what-where"
       * linkedListNext->prev = linkedListPrev  "at the address that next/WHAT points plus 4
       *                    (because prev is the second field in 'list' hence
       *                    4 bytes away on 32b machines), write prev/WHERE"
       */
      linkedListPrev = data.list.prev;
      linkedListNext = data.list.next;
      linkedListPrev->next = linkedListNext;
      linkedListNext->prev = linkedListPrev;
  }
  
  #endif /* OMITBAD */
  
  #ifndef OMITGOOD
  
  /* goodG2B1() - use goodsource and badsink by changing the 1 to 0 */
  static void goodG2B1()
  {
      badStruct data;
      linkedList head = { &head, &head };
      /* This simulates a Microsoft-style linked list insertion */
      data.list.next = head.next;
      data.list.prev = head.prev;
      head.next = &data.list;
      head.prev = &data.list;
      if(0)
      {
          /* INCIDENTAL: CWE 561 Dead Code, the code below will never run */
          printLine("Benign, fixed string");
      }
      else
      {
          /* FIX: don't overwrite linked list pointers */
          ; /* empty statement needed by some flow variants */
      }
      /* POTENTIAL FLAW: The following removes 'a' from the list.  Because of the possible overflow this
       * causes a "write-what-where" aka "write4".  It does another write as
       * well.  But this is the prototypical "write-what-where" at least from
       * the Windows perspective.
       *
       * linkedListPrev = a->list->prev  WHAT
       * linkedListNext = a->list->next  WHERE
       * linkedListPrev->next = linkedListNext  "at the address that prev/WHERE points, write
       *                    next/WHAT"
       *                    aka "write-what-where"
       * linkedListNext->prev = linkedListPrev  "at the address that next/WHAT points plus 4
       *                    (because prev is the second field in 'list' hence
       *                    4 bytes away on 32b machines), write prev/WHERE"
       */
      linkedListPrev = data.list.prev;
      linkedListNext = data.list.next;
      linkedListPrev->next = linkedListNext;
      linkedListNext->prev = linkedListPrev;
  }
  
  /* goodG2B2() - use goodsource and badsink by reversing the blocks in the if statement */
  static void goodG2B2()
  {
      badStruct data;
      linkedList head = { &head, &head };
      /* This simulates a Microsoft-style linked list insertion */
      data.list.next = head.next;
      data.list.prev = head.prev;
      head.next = &data.list;
      head.prev = &data.list;
      if(1)
      {
          /* FIX: don't overwrite linked list pointers */
          ; /* empty statement needed by some flow variants */
      }
      /* POTENTIAL FLAW: The following removes 'a' from the list.  Because of the possible overflow this
       * causes a "write-what-where" aka "write4".  It does another write as
       * well.  But this is the prototypical "write-what-where" at least from
       * the Windows perspective.
       *
       * linkedListPrev = a->list->prev  WHAT
       * linkedListNext = a->list->next  WHERE
       * linkedListPrev->next = linkedListNext  "at the address that prev/WHERE points, write
       *                    next/WHAT"
       *                    aka "write-what-where"
       * linkedListNext->prev = linkedListPrev  "at the address that next/WHAT points plus 4
       *                    (because prev is the second field in 'list' hence
       *                    4 bytes away on 32b machines), write prev/WHERE"
       */
      linkedListPrev = data.list.prev;
      linkedListNext = data.list.next;
      linkedListPrev->next = linkedListNext;
      linkedListNext->prev = linkedListPrev;
  }
  
  void CWE123_Write_What_Where_Condition__listen_socket_02_good()
  {
      goodG2B1();
      goodG2B2();
  }
  
  #endif /* OMITGOOD */
  
  /* Below is the main(). It is only used when building this testcase on
   * its own for testing or for building a binary to use in testing binary
   * analysis tools. It is not used when compiling all the testcases as one
   * application, which is how source code analysis tools are tested.
   */
  
  #ifdef INCLUDEMAIN
  
  int main(int argc, char * argv[])
  {
      /* seed randomness */
      srand( (unsigned)time(NULL) );
  #ifndef OMITGOOD
      printLine("Calling good()...");
      CWE123_Write_What_Where_Condition__listen_socket_02_good();
      printLine("Finished good()");
  #endif /* OMITGOOD */
  #ifndef OMITBAD
      printLine("Calling bad()...");
      CWE123_Write_What_Where_Condition__listen_socket_02_bad();
      printLine("Finished bad()");
  #endif /* OMITBAD */
      return 0;
  }
  
  #endif
  