extended functionality/make more secure M.Z.

conman.c

@@ -29,6 +29,11 @@
         appending outcode to text,
 	Mark Koennecke, July 2004
 	
+        Made use of unused connections secure (connections are not
+        freed, but reused on new connections).
+        Introduced new type SCStore and functions SCSave, SCLoad.
+        Introduced SCPrintf to avoid many of these pBueffel.
+        Markus Zolliker, Sept 2004.
 
 	Copyright: see copyright.h
 -----------------------------------------------------------------------------*/
@@ -41,6 +46,8 @@
 #include <zlib.h>
 #include <tcl.h>
 #include <time.h>
+#include <limits.h>
+#include <stdarg.h>
 #include "lld.h"
 #include "sics.h"
 #include "passwd.h"
@@ -78,173 +85,143 @@ extern pServer pServ;
 /*------------- a number for generating automatic names --------------------*/
   static int iName = 0;
   static int SCNormalWrite(SConnection *self, char *buffer, int iOut);
-
+  static SConnection *freeConnections = NULL;
+  static long lastIdent = 0;
 /*===========================================================================*/
-   SConnection *SCreateConnection(SicsInterp *pSics,mkChannel *pSock, int iUser)
+  static char *ConName(long ident) {
+    static char name[32];
+    snprintf(name, sizeof(name), "CON%ld", ident);
+    return name;
+  }
+/*--------------------------------------------------------------------------*/
+  static void FreeConnection(SConnection *pCon)
+  {
+    memset(pCon,0,sizeof(SConnection));
+    pCon->ident = 0;
+    pCon->next = freeConnections;
+    freeConnections = pCon;
+  }
+/*--------------------------------------------------------------------------*/
+  static SConnection *CreateConnection(SicsInterp *pSics)
+  {
+    int i;
+    SConnection *pRes = NULL;
+    char pBueffel[253];
+    char pHost[132];
+     
+    if (!freeConnections)
+    { /* no more free connection: get one by malloc */
+      pRes = (SConnection *)malloc(sizeof(SConnection));
+      if(!pRes)
+      {
+        /* This is a serious, very serious error! */
+        SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
+        return NULL;
+      }
+      memset(pRes,0,sizeof(SConnection));
+    }
+    else
+    { /* reuse an old connection */
+      pRes = freeConnections;
+      freeConnections = pRes->next;
+    }
+    
+    do
+    { /* loop until an unused ident is found */
+      if (lastIdent == LONG_MAX)
+      {
+        /* This is a serious, very serious error! */
+        SICSLogWrite("ERROR: Run out of connection identifiers!!",eInternal);
+        return NULL;
+      }
+      lastIdent++;
+    } while (FindCommand(pSics, ConName(lastIdent)));
+    pRes->ident = lastIdent;
+     
+    /* a descriptor */
+    pRes->pDes = CreateDescriptor("Connection");
+    if(!pRes->pDes)
+    {
+      /* This is a serious, very serious error! */
+      SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
+      FreeConnection(pRes);
+      return NULL;
+    }
+    
+    /* the callback registry */
+    pRes->iList = LLDcreate(sizeof(Item));
+    
+    /* the command stack */
+    pRes->pStack = CreateCommandStack();
+    if( (pRes->iList <0) || (!pRes->pStack))
+    {
+      /* This is a serious, very serious error! */
+      SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
+      DeleteDescriptor(pRes->pDes);
+      FreeConnection(pRes);
+      return NULL;
+    }
+
+    pRes->iOutput = eInError; /* gets everything except internal messages */
+    pRes->iFiles = 0;  /* default: no logfiles */
+    pRes->inUse = 0;
+    pRes->iMacro = 0;
+    pRes->iTelnet = 0;
+    pRes->pSics = pSics;
+    pRes->eInterrupt = eContinue;
+    pRes->lMagic = CONMAGIC;
+    pRes->iLogin = 0;
+    pRes->conStart = time(NULL);
+    pRes->write = SCNormalWrite;
+    for(i = 0; i < 10; i++)
+    {
+      pRes->pFiles[i] = NULL;
+    }   
+    
+    /* install command */
+    AddCommand(pRes->pSics, ConName(pRes->ident), ConSicsAction, NULL,pRes);
+    return pRes;   
+     
+  }
+/*--------------------------------------------------------------------------*/
+  SConnection *SCreateConnection(SicsInterp *pSics,mkChannel *pSock, int iUser)
   {
-     int i;
      SConnection *pRes = NULL;
      char pBueffel[253];
      char pHost[132];
      
-     pRes = (SConnection *)malloc(sizeof(SConnection));
+     assert(pSock);
-     if(!pRes)
-     {
-       /* This is a serious, very serious error! */
-       SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
-       return NULL;
-     }
-     memset(pRes,0,sizeof(SConnection));
      
-     /* a descriptor */
+     pRes = CreateConnection(pSics);
-     pRes->pDes = CreateDescriptor("Connection");
-     if(!pRes->pDes)
-     {
-       /* This is a serious, very serious error! */
-       SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
-       free(pRes);
-       return NULL;
-     }
      
-      /* new name */
-      sprintf(pBueffel,"CON%4.4d",iName);
-      iName++;
-      if(iName > 9999)
-      {
-        iName = 0;
-      }
-     
-     /* the callback registry */
-     pRes->iList = LLDcreate(sizeof(Item));
-     
-     /* the command stack */
-     pRes->pStack = CreateCommandStack();
-     if( (pRes->iList <0) || (!pRes->pStack))
-     {
-       /* This is a serious, very serious error! */
-       SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
-       DeleteDescriptor(pRes->pDes);
-       free(pRes);
-       return NULL;
-     }
      SetCommandStackMaxSize(pRes->pStack,MAXSTACK);
 
-     pRes->pName = strdup(pBueffel);     
      pRes->pSock = pSock;
      pRes->iUserRights = iUser;
-     pRes->iOutput = eInError; /* gets everything except internal messages */
+     pRes->iGrab =  TokenGrabActive();
-     pRes->iFiles = 0;  /* default: no logfiles */
+
-     pRes->inUse = 0;
+     NETInfo(pRes->pSock,pHost,131);
-     pRes->iMacro = 0;
+     sprintf(pBueffel,"Accepted connection on socket %d from %s",
-     pRes->iGrab = TokenGrabActive();
+             pRes->pSock->sockid, pHost);
-     pRes->iTelnet = 0;
+     SICSLogWrite(pBueffel,eInternal);
-     pRes->pSics = pSics;
+     WriteToCommandLog("SYS >", pBueffel);
-     pRes->eInterrupt = eContinue;
-     pRes->lMagic = CONMAGIC;
-     pRes->iLogin = 0;
-     pRes->conStart = time(NULL);
-     pRes->write = SCNormalWrite;
-     for(i = 0; i < 10; i++)
-     {
-       pRes->pFiles[i] = NULL;
-     }   
-     if(pRes->pSock)
-     {
-       NETInfo(pRes->pSock,pHost,131);
-       sprintf(pBueffel,"Accepted connection on socket %d from %s",
-               pRes->pSock->sockid, pHost);
-       SICSLogWrite(pBueffel,eInternal);
-       WriteToCommandLog("SYS >", pBueffel);
-     }
-     else
-     {
-       SICSLogWrite("Accepted dummy connection ",eInternal);
-     }
 
-     /* install command */
-     AddCommand(pRes->pSics, pRes->pName, ConSicsAction, NULL,pRes);
      return pRes;   
      
   }
 /*--------------------------------------------------------------------------*/
   SConnection *SCCreateDummyConnection(SicsInterp *pSics)
   {
-     int i;
      SConnection *pRes = NULL;
-     char pBueffel[132];
      
-     pRes = (SConnection *)malloc(sizeof(SConnection));
+     pRes = CreateConnection(pSics);
-     if(!pRes)
-     {
-       /* This is a serious, very serious error! */
-       SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
-       return NULL;
-     }
-     memset(pRes,0,sizeof(SConnection));
      
-     /* a descriptor */
-     pRes->pDes = CreateDescriptor("Connection");
-     if(!pRes->pDes)
-     {
-       /* This is a serious, very serious error! */
-       SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
-       free(pRes);
-       return NULL;
-     }
-
-      /* new name */
-      sprintf(pBueffel,"CON%4.4d",iName);
-      iName++;
-      if(iName > 9999)
-      {
-        iName = 0;
-      }
-     
-     /* the callback registry */
-     pRes->iList = LLDcreate(sizeof(Item));
-     
-     /* the command stack */
-     pRes->pStack = CreateCommandStack();
-     if( (pRes->iList <0) || (!pRes->pStack))
-     {
-       /* This is a serious, very serious error! */
-       SICSLogWrite("ERROR: No memory to allocate connection!!",eInternal);
-       DeleteDescriptor(pRes->pDes);
-       free(pRes);
-       return NULL;
-     }
-
-     pRes->pName = strdup(pBueffel);     
      pRes->pSock = NULL;
      pRes->iUserRights = usInternal;
-     pRes->iOutput = eInError; /* gets everything except internal messages */
-     pRes->iFiles = 0;  /* default: no logfiles */
-     pRes->inUse = 0;
-     pRes->iTelnet = 0;
      pRes->iGrab = 0;
-     pRes->iMacro = 0;
-     pRes->pSics = pSics;
-     pRes->lMagic = CONMAGIC;
-     pRes->eInterrupt = eContinue;
-     pRes->iLogin = 0;
-     pRes->conStart = time(NULL);
-     pRes->write = SCNormalWrite;
-     for(i = 0; i < 10; i++)
-     {
-       pRes->pFiles[i] = NULL;
-     }   
-     if(pRes->pSock)
-     {
-       sprintf(pBueffel,"Accepted connection on socket %d",pRes->pSock->sockid);
-       SICSLogWrite(pBueffel,eInternal);
-     }
-     else
-     {
-       SICSLogWrite("Accepted dummy connection ",eInternal);
-     }
      
-     /* install command */
+     SICSLogWrite("Accepted dummy connection ",eInternal);
-     AddCommand(pRes->pSics, pRes->pName, ConSicsAction, NULL,pRes);
+     
      return pRes;   
   }    
 /*--------------------------------------------------------------------------*/
@@ -434,11 +411,7 @@ extern pServer pServ;
       fclose(pVictim->pFiles[i]);
     }    
 
-    if(pVictim->pName)
+    RemoveCommand(pVictim->pSics,ConName(pVictim->ident));
-    {
-      RemoveCommand(pVictim->pSics,pVictim->pName);
-      free(pVictim->pName);
-    }
     
      if(pVictim->pDes)
      {
@@ -468,9 +441,9 @@ extern pServer pServ;
     {
       DeleteCommandStack(pVictim->pStack);
     }
-    pVictim->lMagic=0; /* make a write to a freed conn. harmless */
+    pVictim->lMagic=0; /* make a write to a freed connection harmless */
     /* finally free pVictim*/
-    free(pVictim);   
+    FreeConnection(pVictim);   
   }
 /*---------------------------------------------------------------------------*/
   static int HasNL(char *buffer)
@@ -563,6 +536,32 @@ extern pServer pServ;
       }
       return self->write(self,pBuffer,iOut);
   }
+/*-------------------------------------------------------------------------*/
+  int SCPrintf(SConnection *self, int iOut, char *fmt, ...)
+  {
+      va_list ap;
+      char buf[256];
+      char *dyn;
+      int l;
+      int res;
+      
+      va_start(ap, fmt);
+      l = vsnprintf(buf, sizeof buf, fmt, ap);
+      va_end(ap);
+      if (l >= sizeof buf) {
+        /* we have probably a C99 conforming snprintf and need a larger buffer */
+        dyn = malloc(l+1);
+        if (dyn != NULL) {
+          va_start(ap, fmt);
+          vsnprintf(dyn, l+1, fmt, ap);
+          va_end(ap);
+          res = SCWrite(self, dyn, iOut);
+          free(dyn);
+          return res;
+        }
+      }
+      return SCWrite(self, buf, iOut);
+  }
 /*-------------------------------------------------------------------------*/
 writeFunc SCGetWriteFunc(SConnection *self)
 {
@@ -597,7 +596,7 @@ static int doSockWrite(SConnection *self, char *buffer)
       iRet = NETWrite(self->pSock,buffer,strlen(buffer));
       if(!HasNL(buffer))
       {
-	iRet = NETWrite(self->pSock,"\n",sizeof("\n"));
+	iRet = NETWrite(self->pSock,"\n",strlen("\n"));
       }  
     }
     if(!iRet)
@@ -1396,7 +1395,7 @@ static void writeToLogFiles(SConnection *self, char *buffer)
        }
        else if(strcmp(argv[1],"myname") == 0)
        {
-         sprintf(pBueffel,"MyName = %s",pCon->pName);
+         sprintf(pBueffel,"MyName = %s",ConName(pCon->ident));
          SCWrite(pCon,pBueffel,eValue);
          return 1;
        }
@@ -1904,3 +1903,22 @@ int SCActive(SConnection *self)
   }
   return 0;
 }
+/*--------------------------------------------------------------------------*/
+void SCSave(SCStore *con, SConnection *pCon) {
+  con->pCon = pCon;
+  if (pCon) {
+    con->ident = pCon->ident;
+  }
+}
+/*--------------------------------------------------------------------------*/
+SConnection *SCLoad(SCStore *con) {
+  SConnection *pCon;
+    
+  pCon = con->pCon;
+  if (pCon) {
+    if (con->ident != pCon->ident) {
+      con->pCon == NULL; /* connection has died */
+    }
+  }
+  return pCon;
+}

conman.h

@@ -30,8 +30,10 @@ typedef int (*writeFunc)(struct __SConnection *pCon,
    typedef struct __SConnection {
                                   /* object basics */
                                   pObjectDescriptor pDes;
-                                  char *pName;
+                                  /* char *pName; now generated on the fly from ident */
                                   long lMagic;
+                                  long ident;
+                                  struct __SConnection *next;
                                  
                                   /* I/O control */
                                   mkChannel *pSock;
@@ -62,15 +64,16 @@ typedef int (*writeFunc)(struct __SConnection *pCon,
                                   /* callback registry */
                                   int iList;
 
-                                   /* Tasking Stuff */
+                                  /* Tasking Stuff */
-                                   int iEnd;
+                                  int iEnd;
-                                   /* for keeping track of the login
+                                  /* for keeping track of the login
-                                      process on a non telnet connection.
+                                     process on a non telnet connection.
-                                      Should only be used in SCTaskFunction
+                                     Should only be used in SCTaskFunction
-                                   */
+                                  */
-                                   int iLogin;
+                                  int iLogin;
-                                   time_t conStart;
+                                  time_t conStart;
-                                 }SConnection;
+                                  
+                                } SConnection;
 
 #include "nserver.h"
 
@@ -88,6 +91,7 @@ typedef int (*writeFunc)(struct __SConnection *pCon,
   int SCDelLogFile(SConnection *pCon, int iFile);
   void SCSetOutputClass(SConnection *self, int iClass);
   int SCWrite(SConnection *self, char *pBuffer, int iOut);
+  int SCPrintf(SConnection *self, int iOut, char *fmt, ...);
   int SCRead(SConnection *self, char *pBuffer, int iBufLen);   
   int SCPrompt(SConnection *pCon, char *pPrompt, char *pResult, int iLen);
   int SCSendOK(SConnection *self);
@@ -140,7 +144,16 @@ typedef int (*writeFunc)(struct __SConnection *pCon,
                      int argc, char *argv[]);                              
        int ConSicsAction(SConnection *pCon, SicsInterp *pSics, void *pData,
                      int argc, char *argv[]);                              
+/******************************** Store ************************************/
+typedef struct {
+  SConnection *pCon;
+  long ident;
+} SCStore;
 
+void SCSave(SCStore *con, SConnection *pCon);
+/* save a connection for later use. */
 
+SConnection *SCLoad(SCStore *con);
+/* check con and return SConnection if still valid or NULL otherwise. */
 
 #endif