GCC 4.4.2 SSP and uClibc

Mwanguhya Daniel Murungi dmurungi at dicts.mak.ac.ug
Fri Nov 27 00:58:47 PST 2009


Don't know what problem ur facing exactly but I now have a working system
using the SSP from uClibc ( and GCC (4.2.4). 

The issue is to do with how GCC handles SSP on TLS and non TLS systems.

Attached is the patch I used to get it working. It's by Natanel Copa from 
Alpine Linux. Only problem is Robert's FORTIFY_SOURCE patch generates an 
internal compiler error during the build. 

I remember u were also interested in Linux PAM on uClibc; am using version 
Linux-PAM-1.0.4 and all is well. I can share the patches if ur still 


On Thursday 26 November 2009 06:45:16 Kevin Day wrote:
> I am trying to figure out where the problem I have is, if it is some
> unusual bug as a result of my own deviations, a bug in uClibc and not
> glibc, or a bug with GCC.
> I am using GCC's libssp for SSP.
> There is an old upstream bug report of the same exact problem:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38274
> I would get an Illegal Instruction and a core dump with any
> appropriate SSP test at:
> http://www.linuxfromscratch.org/hlfs/view/unstable/glibc-2.6/chapter06/butt
> I ended up identifying that the problem exists somewhere with the exit
> process after a stack smash happens and is handled.
> I experimentally decided to take the ssp exit code directly from
> uClibc-
> Replacing the exit code and exiting with SIGKILL, the program now
> reports the Stack Smashing and exits without crashing and core
> dumping.
> Interestingly, if I used SIGABRT with the uClibc code, the program
> would crash and core dump.
> My system for the test case is uClibc- based with gcc-4.4.2
> and binutils-2.20.
> I do not remember seeing this problem way back whenever I was using
> the book's GCC and Binutils.
> The book specifies gcc-4.1.2 and binutils 2.17, so I assume this
> combination properly aborts with crashing?
> Has anybody on this list tried gcc-4.4.2 with SSP either under glibc or
> uClibc?
> Does this segfault happen when uClibc's internal ssp is used instead
> of the GCC libssp?
> --
> Kevin Day

Mwanguhya Daniel Murungi
Makerere University [ DICTS ]
P.O.Box 7062, Wandegeya

MYTH: Knowledge is power
TRUTH: APPLIED Knowledge is power
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