Thank you, I must then apologize to the GCC mailing list for bringing up something off topic.
About GCC's _stack_chk_fail. Yeah, it's much simpler. Personally, I wouldn't trust syslog but I'm not sure of a good alternative. I'll go bother the GLibc people. Thank you, Steven Stewart-Gallus P.S. I'm not sure if the write to the terminal should handle EINTR. I know for pipes that EINTR doesn't happen on Linux but I have no idea for the /dev/tty special file. ----- Original Message ----- From: Ian Lance Taylor <i...@google.com> Date: Saturday, March 29, 2014 1:03 pm Subject: Re: Could we harden GCC's stack smashing? (Re: Adam Zabrocki's Adventure with stack smashing protection) To: Steven Stewart-Gallus <sstewartgallu...@mylangara.bc.ca> Cc: GCC Development <gcc@gcc.gnu.org> > On Sat, Mar 29, 2014 at 10:52 AM, Steven Stewart-Gallus > <sstewartgallu...@mylangara.bc.ca> wrote: > > > > Adam Zabrocki's Adventure with stack smashing protection at > > (http://blog.pi3.com.pl/?p=485 ) is kind of interesting. It lists > some possible > > weaknesses in GCC's -fstack-protector. Given that the weaknesses > happen when the > > stack has already been smashed I do not think they are critical > but they do bug > > me. I think that the issues happen due to the fundamental problem > with the > > approach that GCC's reporting method is taking. Instead of > dealing with the > > messed up state of the process it could exec a whole new process > or simply > > abort. We could also actually raise our own SIGSEGV signal. I > coded up a small > > illustration of how the exec strategy would work. > > Thanks. The code in question is actually part of glibc, not GCC. All > GCC does is call __stack_chk_fail. You may want to take your concerns > to the glibc developers--see http://sourceware.org/glibc. > > GCC does have it's own copy of __stack_chk_fail in libssp, but it's > simpler than the glibc version. > > Ian >
