Do not print backtraces on fatal glibc errors

If the process is in a bad state, we used to print backtraces in
many cases.  This is problematic because doing so could involve
a lot of work, like loading libgcc_s using the dynamic linker,
and this could itself be targeted by exploit writers.  For example,
if the crashing process was forked from a long-lived process, the
addresses in the error message could be used to bypass ASLR.

Commit ed421fca42fd9b4cab7c66e77894b8dd7ca57ed0 ("Avoid backtrace from
__stack_chk_fail [BZ #12189]"), backtraces where no longer printed
because backtrace_and_maps was always called with do_abort == 1.

Rather than fixing this logic error, this change removes the backtrace
functionality from the sources.  With the prevalence of external crash
handlers, it does not appear to be particularly useful.  The crash
handler may also destroy useful information for debugging.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 0 insertions, 4 deletions

diff --git a/include/stdio.h b/include/stdio.h
index 5302e61024..bea2066cd1 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -102,7 +102,6 @@ enum __libc_message_action
 {
   do_message	= 0,		/* Print message.  */
   do_abort	= 1 << 0,	/* Abort.  */
-  do_backtrace	= 1 << 1	/* Backtrace.  */
 };
 
 /* Print out MESSAGE (which should end with a newline) on the error output
@@ -112,10 +111,7 @@ extern void __libc_fatal (const char *__message)
 extern void __libc_message (enum __libc_message_action action,
 			    const char *__fnt, ...) attribute_hidden;
 extern void __fortify_fail (const char *msg) __attribute__ ((__noreturn__));
-extern void __fortify_fail_abort (_Bool, const char *msg)
-  __attribute__ ((__noreturn__)) attribute_hidden;
 libc_hidden_proto (__fortify_fail)
-libc_hidden_proto (__fortify_fail_abort)
 
 /* Acquire ownership of STREAM.  */
 extern void __flockfile (FILE *__stream) attribute_hidden;