Re: Disable printing bug?

[Mark . Burgess]

Thanks, these are mostly fixed already. The problem seems to be that
readlink works differently in different C libaries. The linux version 
does not even append a zero byte at the end! Thanks again,

Mark


On 14 Feb, Iain Morgan wrote:
> I haven't seen anyone address this issue. The problem is due to using
> readlink() without first initializing the buffer.  I have found a few
> other instances where this problem could occur.
> 
> The attached patch rectifies these issues. It also sets the length of the
> buffer to bufsize - 1 when calling readlink.  This is to ensure that the
> resulting string is properly terminated. (Remember that readlink() does not
> null-terminate the string that it places in the buffer.)
> 
> There is one call to cfreadlink() in image.c that may still require 
> initialization of the buffer.  It might actually be a good idea to
> do the initialization of the buffer inside of cfreadlink() to avoid any
> future issues.
> 
> I have not checked if this patch interferes with any patches that have been
> released after 1.6.2. Also I have not done any rigorous testing.  The only
> testing that I have done so far is to confirm that cfengine compiles
> correctly with the patch.
> 
> On Thu Jan 25 17:34:45 2001, Robert Shaw wrote:
>> 
>> Mark,
>> 
>> After upgrading to 1.6.2 (at least I think it occurs only with the 
>> new version, not verified though). If I have a "disable:" action 
>> setup for an item, and it goes to delete a link, the message looks a 
>> little messed up:
>> 
>> cf:arizona5: Deleting link /usr/bin/perl -> /usr/local/bin/perle
>> cf:arizona5: Deleting link /usr/bin/python -> /usr/local/bin/pythondx
>> 
>> Notice the trailing characters. They don't really exist in what the 
>> link was pointing to. This looks like a cosmetic problem only, but I 
>> can't be sure if it will affect anything else.
>> 
>> Can you please look at it?
>> 
>> Thanks.
>> -Robert
>> -- 
>> -Robert
>>   mailto:address@hidden
>>   http://members.home.net/rshaw-az/
>>   AIM: RShawPPC
>> 
>> _______________________________________________
>> Bug-cfengine mailing list
>> address@hidden
>> http://mail.gnu.org/mailman/listinfo/bug-cfengine
>> 
> 
> diff -uar cfengine-1.6.2.orig/src/cfd.c cfengine-1.6.2/src/cfd.c
> --- cfengine-1.6.2.orig/src/cfd.c     Sun Jan 14 11:25:09 2001
> +++ cfengine-1.6.2/src/cfd.c  Wed Feb 14 12:34:30 2001
> @@ -1967,7 +1967,7 @@
>     cfst.cf_lmode = statbuf.st_mode & 07777;
>     cfst.cf_nlink = statbuf.st_nlink;
>         
> -   if (readlink(filename,linkbuf,bufsize) == -1)
> +   if (readlink(filename,linkbuf,bufsize - 1) == -1)
>        {
>        sprintf(sendbuffer,"BAD: unable to read link\n");
>        CfLog(cferror,sendbuffer,"readlink");
> diff -uar cfengine-1.6.2.orig/src/do.c cfengine-1.6.2/src/do.c
> --- cfengine-1.6.2.orig/src/do.c      Thu Nov 30 15:06:46 2000
> +++ cfengine-1.6.2/src/do.c   Wed Feb 14 12:36:50 2001
> @@ -1455,7 +1455,8 @@
>           continue;
>           }
>  
> -      if (readlink(workname,VBUFF,bufsize) == -1)
> +      bzero (VBUFF, bufsize);
> +      if (readlink(workname,VBUFF,bufsize - 1) == -1)
>           {
>           sprintf(OUTPUT,"DisableFiles() can't read link %s\n",workname);
>        CfLog(cferror,OUTPUT,"readlink");
> diff -uar cfengine-1.6.2.orig/src/edittools.c cfengine-1.6.2/src/edittools.c
> --- cfengine-1.6.2.orig/src/edittools.c       Mon Jan  1 09:38:32 2001
> +++ cfengine-1.6.2/src/edittools.c    Wed Feb 14 12:39:26 2001
> @@ -254,7 +254,7 @@
>        bzero(linkname,bufsize);
>        bzero(realname,bufsize);
>        
> -      if (readlink(filename,linkname,bufsize) == -1)
> +      if (readlink(filename,linkname,bufsize - 1) == -1)
>        {
>        sprintf(OUTPUT,"Cannot read link %s\n",filename);
>        CfLog(cferror,OUTPUT,"readlink");
> diff -uar cfengine-1.6.2.orig/src/filters.c cfengine-1.6.2/src/filters.c
> --- cfengine-1.6.2.orig/src/filters.c Sun Dec 10 10:36:04 2000
> +++ cfengine-1.6.2/src/filters.c      Wed Feb 14 12:44:12 2001
> @@ -1291,7 +1291,8 @@
>     return false;
>     }
>   
> -if (readlink(filename,buffer,bufsize) == -1)
> +bzero (buffer, bufsize);
> +if (readlink(filename,buffer,bufsize - 1) == -1)
>     {
>     sprintf(OUTPUT,"Unable to read link %s in filter",filename);
>     CfLog(cferror,OUTPUT,"readlink");
> diff -uar cfengine-1.6.2.orig/src/image.c cfengine-1.6.2/src/image.c
> --- cfengine-1.6.2.orig/src/image.c   Fri Jan  5 13:27:53 2001
> +++ cfengine-1.6.2/src/image.c        Wed Feb 14 13:02:26 2001
> @@ -1046,7 +1046,7 @@
>  
>  if (strcmp(ip->server,"localhost") == 0)
>     {
> -   return readlink(sourcefile,linkbuf,buffsize);
> +   return readlink(sourcefile,linkbuf,buffsize - 1);
>     }
>  
>  for (sp = ip->cache; sp != NULL; sp=sp->next)
> diff -uar cfengine-1.6.2.orig/src/link.c cfengine-1.6.2/src/link.c
> --- cfengine-1.6.2.orig/src/link.c    Wed Oct 18 05:28:14 2000
> +++ cfengine-1.6.2/src/link.c Wed Feb 14 13:20:00 2001
> @@ -355,7 +355,7 @@
>        CfLog(cfverbose,OUTPUT,"");
>        
>        bzero(VBUFF,bufsize);
> -         if (readlink(newto,VBUFF,bufsize) != -1)
> +         if (readlink(newto,VBUFF,bufsize - 1) != -1)
>              {
>              Verbose("File is link to -> %s\n",VBUFF);
>              }
> @@ -565,7 +565,7 @@
>  
>  bzero(linkbuf,bufsize);
>  
> -if (readlink(from,linkbuf,bufsize) == -1)
> +if (readlink(from,linkbuf,bufsize - 1) == -1)
>     {
>     if (! MakeDirectoriesFor(from))                  /* link doesn't exist */
>        {
> @@ -821,7 +821,7 @@
>  bzero(linkbuf,bufsize);
>  bzero(linkpath,bufsize); 
>  
> -if (readlink(name,linkbuf,bufsize) == -1)
> +if (readlink(name,linkbuf,bufsize - 1) == -1)
>     {
>     sprintf(OUTPUT,"(Can't read link %s while checking for 
> deadlinks)\n",name);
>     CfLog(cfverbose,OUTPUT,"");
> @@ -1089,7 +1089,7 @@
>        {
>        bzero(buff,bufsize);
>        
> -      if (readlink(dest,buff,bufsize) == -1)
> +      if (readlink(dest,buff,bufsize - 1) == -1)
>        {
>        sprintf(OUTPUT,"Expand links can't stat %s\n",dest);
>        CfLog(cferror,OUTPUT,"readlink");
> diff -uar cfengine-1.6.2.orig/src/tidy.c cfengine-1.6.2/src/tidy.c
> --- cfengine-1.6.2.orig/src/tidy.c    Tue Nov 21 13:20:49 2000
> +++ cfengine-1.6.2/src/tidy.c Wed Feb 14 13:12:33 2001
> @@ -137,7 +137,8 @@
>              {
>              sprintf(OUTPUT,"Can't stat %s\n",pcwd);
>           CfLog(cferror,OUTPUT,"lstat");
> -            if (readlink(pcwd,VBUFF,bufsize) != -1)
> +         bzero (VBUFF, sizeof (VBUFF));
> +            if (readlink(pcwd,VBUFF,bufsize - 1) != -1)
>                 {
>                 sprintf(OUTPUT,"File is link to -> %s\n",VBUFF);
>              CfLog(cferror,OUTPUT,"");
> @@ -283,7 +284,8 @@
>        sprintf(OUTPUT,"Can't stat %s\n",name);
>        CfLog(cferror,OUTPUT,"");
>        
> -      if (readlink(name,VBUFF,bufsize) != -1)
> +      bzero (VBUFF, sizeof (VBUFF));
> +      if (readlink(name,VBUFF,bufsize - 1) != -1)
>           {
>           sprintf(OUTPUT,"File is link to -> %s\n",VBUFF);
>           CfLog(cferror,OUTPUT,"");
> @@ -346,7 +348,8 @@
>              {
>              sprintf(OUTPUT,"Can't stat %s\n",pcwd);
>           CfLog(cferror,OUTPUT,"lstat");
> -            if (readlink(pcwd,VBUFF,bufsize) != -1)
> +         bzero (VBUFF, sizeof (VBUFF));
> +            if (readlink(pcwd,VBUFF,bufsize - 1) != -1)
>                 {
>                 sprintf(OUTPUT,"File is link to -> %s\n",VBUFF);
>              CfLog(cferror,OUTPUT,"");
> 
> --
> Iain Morgan
> NAS Desktop Support Group

-- 


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