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

[Mark Hatle]

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

>> 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 
>> Signed-off-by: Vaneet Narang 
>> Reviewed-by: Doha Hwang 
>> ---
>> 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

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

[Maninder Singh]

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 
>>> Signed-off-by: Vaneet Narang 
>>> Reviewed-by: Doha Hwang 
>>> ---
>>> 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=3199ee4ebfc37288391e169825b75fa80c6136a3
and applicable after this commit


Thanks,
Maninder Singh
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Re: [yocto] [prelink-cross][PATCH 1/1] rtld.c: LD_PRELOAD bugfix

[Maninder Singh]

Hi,
Ping

>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 
>Signed-off-by: Vaneet Narang 
>Reviewed-by: Doha Hwang 
>---
> 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
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[yocto] [prelink-cross][PATCH 1/1] rtld.c: LD_PRELOAD bugfix

[Maninder Singh]

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 
Signed-off-by: Vaneet Narang 
Reviewed-by: Doha Hwang 
---
 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

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