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Re: Stepping over longjmp presumably broken for glibc
- From: gene <genesh at comcast dot net>
- To: libc-alpha at sources dot redhat dot com
- Date: Sat, 8 Apr 2006 00:43:33 +0000 (UTC)
- Subject: Re: Stepping over longjmp presumably broken for glibc
- References: <20051222232004.EBC981809B6@magilla.sf.frob.com> <43AB3615.5050402@redhat.com>
Ulrich Drepper <drepper <at> redhat.com> writes:
>
> Roland McGrath wrote:
> > I'm somewhat concerned that the jmp_buf "fortification" change is going to
> > break some applications too.
>
> This is why there is LD_POINTER_GUARD. Defining it to 0 disables the
> protection.
>
Hmm, looking at the source (elf/rtld.c):
if (memcmp (envline, "POINTER_GUARD", 13) == 0)
GLRO(dl_pointer_guard) = envline[14] == '0';
break;
Isn't it backward? Having "POINTER_GUARD=0" sets _dl_pointer_guard to 1
which is already 1 by default. Am I missing something?
Thanks!
Gene