130 lines
3.0 KiB
C
130 lines
3.0 KiB
C
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/*
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* Distributed under the terms of the GNU General Public License v2
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* $Header: /var/cvsroot/gentoo-x86/dev-libs/dietlibc/files/ssp.c,v 1.2 2004/12/05 19:25:40 solar Exp $
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*
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* This is a modified version of Hiroaki Etoh's stack smashing routines
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* implemented for glibc.
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*
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* The following people have contributed input to this code.
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* Ned Ludd - <solar[@]gentoo.org>
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* Alexander Gabert - <pappy[@]gentoo.org>
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* The PaX Team - <pageexec[@]freemail.hu>
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* Peter S. Mazinger - <ps.m[@]gmx.net>
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* Yoann Vandoorselaere - <yoann[@]prelude-ids.org>
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* Robert Connolly - <robert[@]linuxfromscratch.org>
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* Cory Visi <cory@visi.name>
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*
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include <sys/time.h>
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#ifdef __PROPOLICE_BLOCK_SEGV__
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#define SSP_SIGTYPE SIGSEGV
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#elif __PROPOLICE_BLOCK_KILL__
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#define SSP_SIGTYPE SIGKILL
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#else
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#define SSP_SIGTYPE SIGABRT
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#endif
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unsigned long __guard = 0UL;
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void
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__guard_setup (void)
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{
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size_t size;
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if (__guard != 0UL)
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return;
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#ifndef __SSP_QUICK_CANARY__
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/*
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* Attempt to open kernel pseudo random device if one exists before
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* opening urandom to avoid system entropy depletion.
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*/
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{
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int fd;
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#ifdef HAVE_DEV_ERANDOM
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if ((fd = open ("/dev/erandom", O_RDONLY)) == (-1))
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#endif
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fd = open ("/dev/urandom", O_RDONLY);
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if (fd != (-1))
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{
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size = read (fd, (char *) &__guard, sizeof (__guard));
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close (fd);
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if (size == sizeof (__guard))
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return;
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}
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}
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#endif
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/* If sysctl was unsuccessful, use the "terminator canary". */
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__guard = 0xFF0A0D00UL;
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{
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/* Everything failed? Or we are using a weakened model of the
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* terminator canary */
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struct timeval tv;
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gettimeofday (&tv, NULL);
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__guard ^= tv.tv_usec ^ tv.tv_sec;
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}
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}
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void
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__stack_smash_handler (char func[], int damaged)
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{
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struct sigaction sa;
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const char message[] = ": stack smashing attack in function ";
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int bufsz, len;
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char buf[512];
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static char *__progname = "dietapp";
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sigset_t mask;
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sigfillset (&mask);
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sigdelset (&mask, SSP_SIGTYPE); /* Block all signal handlers */
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sigprocmask (SIG_BLOCK, &mask, NULL); /* except SIGABRT */
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bufsz = sizeof (buf);
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strcpy (buf, "<2>");
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len = 3;
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strncat (buf, __progname, sizeof (buf) - 4);
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len = strlen (buf);
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if (bufsz > len)
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{
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strncat (buf, message, bufsz - len - 1);
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len = strlen (buf);
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}
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if (bufsz > len)
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{
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strncat (buf, func, bufsz - len - 1);
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len = strlen (buf);
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}
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/* print error message */
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write (STDERR_FILENO, buf + 3, len - 3);
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write (STDERR_FILENO, "()\n", 3);
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/* Make sure the default handler is associated with the our signal handler */
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memset (&sa, 0, sizeof (struct sigaction));
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sigfillset (&sa.sa_mask); /* Block all signals */
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sa.sa_flags = 0;
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sa.sa_handler = SIG_DFL;
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sigaction (SSP_SIGTYPE, &sa, NULL);
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(void) kill (getpid (), SSP_SIGTYPE);
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_exit (127);
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}
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