Re: [prelink-cross][PATCH 1/1] rtld.c: LD_PRELOAD bugfix

* Re: [prelink-cross][PATCH 1/1] rtld.c: LD_PRELOAD bugfix
@ 2015-11-10  1:05 Maninder Singh
  0 siblings, 0 replies; 4+ messages in thread
From: Maninder Singh @ 2015-11-10  1:05 UTC (permalink / raw)
  To: Mark Hatle; +Cc: Vaneet Narang, yocto, PANKAJ MISHRA

Hello,

>On 11/7/15 5:24 AM, Maninder Singh wrote:
>> Hi,
>> Ping....
>
>I'd gotten a msg after this to hold off and wait for an update.  Is this the
>updated version of the fix?
>
>--Mark

Yes, we send message for update a fix for LD_PRELOAD implemntation in prelink:-
https://lists.yoctoproject.org/pipermail/yocto/2015-September/026431.html
 (LD_PRELOAD implemntation patch, which is merged with prelink_cross project)

and this below patch fixes  bug in LD_PRELOAD patch (yes this is updated version of fix).

>>> This patch do following things:-
>>> 1. 	Fixes bug of adding preloaded libs in search scope of dependent 
>>> 	libraries which results in search scope of few symbols becomes 
>>> 	same for executable and library, so conflict doesn't occur for 
>>> 	those symbols and hence resulted in less number of conflicts.
>>> 2. 	Reduce code redundancy.
>>> 3. 	Buffer Overflow fix.
>>>
>>> Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
>>> Signed-off-by: Vaneet Narang <v.narang@samsung.com>
>>> Reviewed-by: Doha Hwang <doha.hwang@samsung.com>
>>> ---
>>> trunk/src/rtld/rtld.c |   27 ++++++++++++++++-----------
>>> 1 files changed, 16 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/trunk/src/rtld/rtld.c b/trunk/src/rtld/rtld.c
>>> index 50461b6..8af5052 100644
>>> --- a/trunk/src/rtld/rtld.c
>>> +++ b/trunk/src/rtld/rtld.c
>>> @@ -606,7 +606,7 @@ load_dsos (DSO *dso, int host_paths)
>>> {
>>>   struct dso_list *dso_list, *dso_list_tail, *cur_dso_ent, *new_dso_ent;
>>>   struct stat64 st;
>>> -  int total_preload = 0;
>>> +  int total_preload = 0, temp_total_preload = 0;
>>>   char * libname[MAX_PRELOADED_LIBS] = {NULL};
>>>
>>>   /* Assume it's static unless we find DT_NEEDED entries */
>>> @@ -632,19 +632,19 @@ load_dsos (DSO *dso, int host_paths)
>>>
>>>   if(dso->ehdr.e_type == ET_EXEC && ld_preload) {
>>>       char *next_lib =  ld_preload;
>>> -      libname[total_preload] = ld_preload;
>>> -      total_preload++;
>>> -      next_lib=strchr(ld_preload,':');
>>> -      while(next_lib!=NULL){
>>> -	  *next_lib = '\0';
>>> -	  next_lib++;
>>> -	  libname[total_preload] = next_lib;
>>> -	  total_preload++;
>>> -	  next_lib=strchr(next_lib,':');
>>> -      }
>>> +      while(*next_lib != '\0' && (total_preload < MAX_PRELOADED_LIBS)){
>>> +        libname[total_preload++] = next_lib;
>>> +        next_lib=strchrnul(next_lib,':');
>>> +        if(*next_lib == '\0')
>>> +          break;
>>> +        *next_lib = '\0';
>>> +        next_lib++;
>>> +     }
>>> +    temp_total_preload = total_preload;
>>>   }
>>>   else {
>>>       total_preload = 0;
>>> +      temp_total_preload = 0;
>>>   }
>>>   while (cur_dso_ent != NULL)
>>>     {
>>> @@ -666,6 +666,11 @@ load_dsos (DSO *dso, int host_paths)
>>> 	{
>>> 	  int ndx, maxndx;
>>> 	  maxndx = data->d_size / cur_dso->shdr[cur_dso->dynamic].sh_entsize;
>>> +      if(!(cur_dso->ehdr.e_type == ET_EXEC))
>>> +        total_preload = 0;
>>> +      else
>>> +        total_preload = temp_total_preload;
>>> +
>>> 	  for (ndx = 0; ndx < maxndx + total_preload; ++ndx)
>>> 	    {
>>>
>>> -- 
>>> 1.7.1

This patch is a fix to a bug of below commit (addition of new --ld-preload option):-
http://git.yoctoproject.org/cgit/cgit.cgi/prelink-cross/commit/?h=cross_prelink&id=3199ee4ebfc37288391e169825b75fa80c6136a3
and applicable after this commit

Thanks,
Maninder Singh

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