i686-w64-mingw32-gcc -fstack-protector-strong

i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

I'm hoping that I'm just missing a library, but which one?  Even
better, how to tell which one?

$ i686-w64-mingw32-gcc -o div.exe div.c
$ ./div
  works

$ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
$ ./div
C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
cannot open shared object file: No such file or directory

$ ldd div.exe
        ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffef5c50000)
        ??? => ??? (0x778f0000)
        wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x50e50000)
        wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll (0x50dd0000)

$ i686-w64-mingw32-gcc --version
i686-w64-mingw32-gcc (GCC) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Thanks
Lee

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Marco Atzeri]

On 08/09/2017 16:14, Lee wrote:
> I'm hoping that I'm just missing a library, but which one?  Even
> better, how to tell which one?
> 
> $ i686-w64-mingw32-gcc -o div.exe div.c
> $ ./div
>    works
> 
> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
> $ ./div
> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
> cannot open shared object file: No such file or directory
> 
> $ ldd div.exe
>          ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffef5c50000)
>          ??? => ??? (0x778f0000)
>          wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x50e50000)
>          wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll (0x50dd0000)
> 

try
   cygcheck ./div.exe



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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

On 9/8/17, Marco Atzeri   wrote:
> On 08/09/2017 16:14, Lee wrote:
>> I'm hoping that I'm just missing a library, but which one?  Even
>> better, how to tell which one?
>>
>> $ i686-w64-mingw32-gcc -o div.exe div.c
>> $ ./div
>>    works
>>
>> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
>> $ ./div
>> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
>> cannot open shared object file: No such file or directory
>>
>> $ ldd div.exe
>>          ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
>> (0x7ffef5c50000)
>>          ??? => ??? (0x778f0000)
>>          wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x50e50000)
>>          wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll
>> (0x50dd0000)
>>
>
> try
>    cygcheck ./div.exe

nothing useful for a non-cygwin program?
$ cygcheck ./div.exe
C:\cygwin\home\Lee\t\div.exe

vs. built using cygwin:
$ gcc -fstack-protector-strong -o div.exe div.c
$ ./div
   works
$ cygcheck ./div.exe
C:\cygwin\home\Lee\t\div.exe
  C:\cygwin\bin\cygwin1.dll
    C:\WINDOWS\system32\KERNEL32.dll
      C:\WINDOWS\system32\ntdll.dll
      C:\WINDOWS\system32\KERNELBASE.dll
  C:\cygwin\bin\cygssp-0.dll



Was there ever a man page for cygcheck?  I remember looking at one,
but maybe I it was https://cygwin.com/cygwin-ug-net/cygcheck.html ??
$ man cygcheck
No manual entry for cygcheck

$ info cygcheck
info: No menu item 'cygcheck' in node '(dir)Top'

Lee

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Marco Atzeri]

On 08/09/2017 20:53, Lee wrote:
> On 9/8/17, Marco Atzeri   wrote:
>> On 08/09/2017 16:14, Lee wrote:
>>> I'm hoping that I'm just missing a library, but which one?  Even
>>> better, how to tell which one?
>>>
>>> $ i686-w64-mingw32-gcc -o div.exe div.c
>>> $ ./div
>>>     works
>>>
>>> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
>>> $ ./div
>>> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
>>> cannot open shared object file: No such file or directory
>>>
>>> $ ldd div.exe
>>>           ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
>>> (0x7ffef5c50000)
>>>           ??? => ??? (0x778f0000)
>>>           wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x50e50000)
>>>           wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll
>>> (0x50dd0000)
>>>
>>
>> try
>>     cygcheck ./div.exe
> 
> nothing useful for a non-cygwin program?
> $ cygcheck ./div.exe
> C:\cygwin\home\Lee\t\div.exe

cygcheck works also for not cygwin program
( cygcheck --help for details)

cd /cygdrive/c/windows/system32

  $ cygcheck ./net.exe
C:\windows\system32\net.exe
   C:\windows\system32\ADVAPI32.dll
     C:\windows\system32\msvcrt.dll
       C:\windows\system32\KERNELBASE.dll
         C:\windows\system32\ntdll.dll
[long cut]
   C:\windows\system32\samcli.dll
   C:\windows\system32\srvcli.dll
   C:\windows\system32\wkscli.dll
   C:\windows\system32\MPR.dll
   C:\windows\system32\IPHLPAPI.DLL
     C:\windows\system32\NSI.dll
     C:\windows\system32\WINNSI.DLL

You can also use

  $ objdump -x ./net.exe |grep -i "dll name"
         DLL Name: ADVAPI32.dll
         DLL Name: KERNEL32.dll
         DLL Name: msvcrt.dll
         DLL Name: ntdll.dll
         DLL Name: netutils.dll
         DLL Name: browcli.dll
         DLL Name: samcli.dll
         DLL Name: srvcli.dll
         DLL Name: wkscli.dll
         DLL Name: MPR.dll
         DLL Name: IPHLPAPI.DLL


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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

On 9/8/17, Marco Atzeri  wrote:
> On 08/09/2017 20:53, Lee wrote:
>> On 9/8/17, Marco Atzeri   wrote:
>>> On 08/09/2017 16:14, Lee wrote:
>>>> I'm hoping that I'm just missing a library, but which one?  Even
>>>> better, how to tell which one?
>>>>
>>>> $ i686-w64-mingw32-gcc -o div.exe div.c
>>>> $ ./div
>>>>     works
>>>>
>>>> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
>>>> $ ./div
>>>> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
>>>> cannot open shared object file: No such file or directory
>>>>
>>>> $ ldd div.exe
>>>>           ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
>>>> (0x7ffef5c50000)
>>>>           ??? => ??? (0x778f0000)
>>>>           wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll
>>>> (0x50e50000)
>>>>           wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll
>>>> (0x50dd0000)
>>>>
>>>
>>> try
>>>     cygcheck ./div.exe
>>
>> nothing useful for a non-cygwin program?
>> $ cygcheck ./div.exe
>> C:\cygwin\home\Lee\t\div.exe
>
> cygcheck works also for not cygwin program
> ( cygcheck --help for details)

   <.. snip examples ..>
> You can also use
>
>   $ objdump -x ./net.exe |grep -i "dll name"
   <.. snip output..>

that's interesting
I've still got the 'i686-w64-mingw32-gcc -fstack-protector-strong' executable:
$ ./div.exe
C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
cannot open shared object file: No such file or directory

$ objdump -x ./div.exe | egrep -i "dll name"
        DLL Name: KERNEL32.dll
        DLL Name: msvcrt.dll
        DLL Name: libssp-0.dll

https://cygwin.com/cgi-bin2/package-grep.cgi?grep=libssp&arch=x86_64
shows libssp0 as the GCC Stack-Smashing Protection runtime library
but I don't see anything like that with a leading "mingw64-i686-"
name, so I'm out of luck?

Thanks,
Lee

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Marco Atzeri]

On 08/09/2017 22:01, Lee wrote:
> On 9/8/17, Marco Atzeri  wrote:
>> On 08/09/2017 20:53, Lee wrote:
>>> On 9/8/17, Marco Atzeri   wrote:
>>>> On 08/09/2017 16:14, Lee wrote:
> I've still got the 'i686-w64-mingw32-gcc -fstack-protector-strong' executable:
> $ ./div.exe
> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
> cannot open shared object file: No such file or directory
> 
> $ objdump -x ./div.exe | egrep -i "dll name"
>          DLL Name: KERNEL32.dll
>          DLL Name: msvcrt.dll
>          DLL Name: libssp-0.dll
> 
> https://cygwin.com/cgi-bin2/package-grep.cgi?grep=libssp&arch=x86_64
> shows libssp0 as the GCC Stack-Smashing Protection runtime library
> but I don't see anything like that with a leading "mingw64-i686-"
> name, so I'm out of luck?
> 


https://cygwin.com/cgi-bin2/package-cat.cgi?file=x86_64%2Fmingw64-i686-gcc-core%2Fmingw64-i686-gcc-core-6.3.0-1&grep=libssp-0.dll

almost at the end:

usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

On 9/8/17, Marco Atzeri  wrote:
> On 08/09/2017 22:01, Lee wrote:
>> On 9/8/17, Marco Atzeri  wrote:
>>> On 08/09/2017 20:53, Lee wrote:
>>>> On 9/8/17, Marco Atzeri   wrote:
>>>>> On 08/09/2017 16:14, Lee wrote:
>> I've still got the 'i686-w64-mingw32-gcc -fstack-protector-strong'
>> executable:
>> $ ./div.exe
>> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
>> cannot open shared object file: No such file or directory
>>
>> $ objdump -x ./div.exe | egrep -i "dll name"
>>          DLL Name: KERNEL32.dll
>>          DLL Name: msvcrt.dll
>>          DLL Name: libssp-0.dll
>>
>> https://cygwin.com/cgi-bin2/package-grep.cgi?grep=libssp&arch=x86_64
>> shows libssp0 as the GCC Stack-Smashing Protection runtime library
>> but I don't see anything like that with a leading "mingw64-i686-"
>> name, so I'm out of luck?
>>
>
>
> https://cygwin.com/cgi-bin2/package-cat.cgi?file=x86_64%2Fmingw64-i686-gcc-core%2Fmingw64-i686-gcc-core-6.3.0-1&grep=libssp-0.dll
>
> almost at the end:
>
> usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll

I already have that
$ ls -l /usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll
-rwxr-xr-x 1 root None 14336 Feb 22  2017
/usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll

But run setup, nothing shows as pending, switch to full view, find the
line & clicking on the version cycles thru Keep -> Reinstall ->
6.3.0-1 -> Uninstall -> 5.4.0-3 -> Keep

Upgrading to 6.3.0-1 doesn't change anything:
$ i686-w64-mingw32-gcc --version
i686-w64-mingw32-gcc (GCC) 6.3.0
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
$ ./div.exe
C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
cannot open shared object file: No such file or directory
$ objdump -x ./div.exe | egrep -i "dll name"
        DLL Name: KERNEL32.dll
        DLL Name: msvcrt.dll
        DLL Name: libssp-0.dll
$ ls -l /usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll
-rwxr-xr-x 1 root None 14336 Aug 17 08:26
/usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll
$

Thanks,
Lee

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RE: i686-w64-mingw32-gcc -fstack-protector-strong

[Nellis, Kenneth]

> From: Lee 
> ... 
> Was there ever a man page for cygcheck?  I remember looking at one,
> but maybe I it was https://cygwin.com/cygwin-ug-net/cygcheck.html ??
> $ man cygcheck
> No manual entry for cygcheck
> 
> $ info cygcheck
> info: No menu item 'cygcheck' in node '(dir)Top'

Both man and info work for me:

$ man cygcheck | head
CYGCHECK(1)                              Cygwin Utilities                             CYGCHECK(1)

NAME
       cygcheck - List system information, check installed packages, or query package database

SYNOPSIS
       cygcheck [-v] [-h] PROGRAM
       cygcheck -c [-d] [PACKAGE]
       cygcheck -s [-r] [-v] [-h]
       cygcheck -k
$ info cygcheck | head
info: No menu item 'cygcheck' in node '(dir)Top'
CYGCHECK(1)                              Cygwin Utilities                             CYGCHECK(1)

NAME
       cygcheck - List system information, check installed packages, or query package database

SYNOPSIS
       cygcheck [-v] [-h] PROGRAM
       cygcheck -c [-d] [PACKAGE]
       cygcheck -s [-r] [-v] [-h]
       cygcheck -k
$

--Ken Nellis

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

On 9/8/17, Nellis, Kenneth wrote:
>> From: Lee
>> ...
>> Was there ever a man page for cygcheck?  I remember looking at one,
>> but maybe I it was https://cygwin.com/cygwin-ug-net/cygcheck.html ??
>> $ man cygcheck
>> No manual entry for cygcheck
>>
>> $ info cygcheck
>> info: No menu item 'cygcheck' in node '(dir)Top'
>
> Both man and info work for me:

Thanks.  I was missing the cygwin-doc package :(

Lee

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Yaakov Selkowitz]

[-- Attachment #1.1: Type: text/plain, Size: 1180 bytes --]

On 2017-09-08 16:08, Lee wrote:
> $ i686-w64-mingw32-gcc --version
> i686-w64-mingw32-gcc (GCC) 6.3.0
> Copyright (C) 2016 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> 
> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
> $ ./div.exe
> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
> cannot open shared object file: No such file or directory
> $ objdump -x ./div.exe | egrep -i "dll name"
>         DLL Name: KERNEL32.dll
>         DLL Name: msvcrt.dll
>         DLL Name: libssp-0.dll
> $ ls -l /usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll
> -rwxr-xr-x 1 root None 14336 Aug 17 08:26
> /usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll

You created a MinGW executable which depends on other MinGW DLLs.
Therefore, either you have to tell it where to find its dependencies:

PATH="$(cygpath -S):$(cygpath
-W):/usr/i686-w64-mingw32/sys-root/mingw/bin:$PATH" \
./div.exe

Or, since you're only using GCC's libraries, just link with -static.

-- 
Yaakov


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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Steven Penny]

On Fri, 8 Sep 2017 10:14:54, Lee wrote:
> $ i686-w64-mingw32-gcc -o div.exe div.c
> $ ./div
>   works
> 
> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
> $ ./div
> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
> cannot open shared object file: No such file or directory
> 
> $ ldd div.exe
>         ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffef5c50000)
>         ??? => ??? (0x778f0000)
>         wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x50e50000)
>         wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll (0x50dd0000)
> 
> $ i686-w64-mingw32-gcc --version
> i686-w64-mingw32-gcc (GCC) 5.4.0

You need to paste or link to div.c, otherwise this seems a pointless exercise.
See, I cannot repro:

$ cat div.c
#include <stdio.h>
int main() {
  puts("hello world");
}

$ x86_64-w64-mingw32-gcc -o div div.c
$ ./div
hello world

$ x86_64-w64-mingw32-gcc -fstack-protector-strong -o div div.c
$ ./div
hello world

$ ldd div
ntdll.dll => /cygdrive/c/Windows/SYSTEM32/ntdll.dll (0x773a0000)
kernel32.dll => /cygdrive/c/Windows/system32/kernel32.dll (0x77180000)
KERNELBASE.dll => /cygdrive/c/Windows/system32/KERNELBASE.dll (0x7fefd1a0000)
msvcrt.dll => /cygdrive/c/Windows/system32/msvcrt.dll (0x7fefde00000)

$ x86_64-w64-mingw32-gcc --version
x86_64-w64-mingw32-gcc (GCC) 5.4.0


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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

On 9/8/17, Yaakov Selkowitz <yselkowitz@cygwin.com> wrote:
> On 2017-09-08 16:08, Lee wrote:
>> $ i686-w64-mingw32-gcc --version
>> i686-w64-mingw32-gcc (GCC) 6.3.0
>> Copyright (C) 2016 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions.  There is
>> NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
>> PURPOSE.
>>
>> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
>> $ ./div.exe
>> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
>> cannot open shared object file: No such file or directory
>> $ objdump -x ./div.exe | egrep -i "dll name"
>>         DLL Name: KERNEL32.dll
>>         DLL Name: msvcrt.dll
>>         DLL Name: libssp-0.dll
>> $ ls -l /usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll
>> -rwxr-xr-x 1 root None 14336 Aug 17 08:26
>> /usr/i686-w64-mingw32/sys-root/mingw/bin/libssp-0.dll
>
> You created a MinGW executable which depends on other MinGW DLLs.
> Therefore, either you have to tell it where to find its dependencies:
>
> PATH="$(cygpath -S):$(cygpath
> -W):/usr/i686-w64-mingw32/sys-root/mingw/bin:$PATH" \
> ./div.exe
>
> Or, since you're only using GCC's libraries, just link with -static.

That was it.  Thank you!!

$ i686-w64-mingw32-gcc -static -fstack-protector-strong -o div.exe div.c
$ ./div
  works
$ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
$ PATH=/usr/i686-w64-mingw32/sys-root/mingw/bin:$PATH  ./div.exe
  works

and follow up question if I may - what should I have read that would
have told me that?

Lee

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Re: i686-w64-mingw32-gcc -fstack-protector-strong

[Lee]

On 9/8/17, Steven Penny <svnpenn@gmail.com> wrote:
> On Fri, 8 Sep 2017 10:14:54, Lee wrote:
>> $ i686-w64-mingw32-gcc -o div.exe div.c
>> $ ./div
>>   works
>>
>> $ i686-w64-mingw32-gcc -fstack-protector-strong -o div.exe div.c
>> $ ./div
>> C:/cygwin/home/Lee/t/div.exe: error while loading shared libraries: ?:
>> cannot open shared object file: No such file or directory
>>
>> $ ldd div.exe
>>         ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
>> (0x7ffef5c50000)
>>         ??? => ??? (0x778f0000)
>>         wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x50e50000)
>>         wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll
>> (0x50dd0000)
>>
>> $ i686-w64-mingw32-gcc --version
>> i686-w64-mingw32-gcc (GCC) 5.4.0
>
> You need to paste or link to div.c, otherwise this seems a pointless
> exercise.
> See, I cannot repro:
>
> $ cat div.c
> #include <stdio.h>
> int main() {
>   puts("hello world");
> }

man gcc

       -fstack-protector
           Emit extra code to check for buffer overflows, such as
stack smashing attacks.  This is done by adding a guard
           variable to functions with vulnerable objects.  This
includes functions that call "alloca", and functions with
           buffers larger than 8 bytes.  The guards are initialized
when a function is entered and then checked when the
           function exits.  If a guard check fails, an error message
is printed and the program exits.

       -fstack-protector-all
           Like -fstack-protector except that all functions are protected.

       -fstack-protector-strong
           Like -fstack-protector but includes additional functions to
be protected --- those that have local array definitions,
           or have references to local frame addresses.


I maybe should have used -fstack-protector-all, but I'm still learning :)

> $ x86_64-w64-mingw32-gcc -o div div.c
> $ ./div
> hello world
>
> $ x86_64-w64-mingw32-gcc -fstack-protector-strong -o div div.c
> $ ./div
> hello world
>
> $ ldd div
> ntdll.dll => /cygdrive/c/Windows/SYSTEM32/ntdll.dll (0x773a0000)
> kernel32.dll => /cygdrive/c/Windows/system32/kernel32.dll (0x77180000)
> KERNELBASE.dll => /cygdrive/c/Windows/system32/KERNELBASE.dll
> (0x7fefd1a0000)
> msvcrt.dll => /cygdrive/c/Windows/system32/msvcrt.dll (0x7fefde00000)

note libssp-0 (or ???) isn't mentioned
you don't have any user defined functions, so it got optimized
out/never called??

Thanks
Lee

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