/*
- * Distributed under the terms of the GNU General Public License v2
- * $Header: /var/cvs/uClibc/libc/sysdeps/linux/common/ssp.c,v 1.4 2004/11/11 03:13:36 solar Exp $
+ * Distributed under the terms of the GNU Lesser General Public License
+ * $Header: $
*
* This is a modified version of Hiroaki Etoh's stack smashing routines
* implemented for glibc.
* Peter S. Mazinger - <ps.m[@]gmx.net>
* Yoann Vandoorselaere - <yoann[@]prelude-ids.org>
* Robert Connolly - <robert[@]linuxfromscratch.org>
- * Cory Visi <cory@visi.name>
- *
+ * Cory Visi <cory[@]visi.name>
+ * Mike Frysinger <vapier[@]gentoo.org>
*/
-#ifdef HAVE_CONFIG_H
-# include <config.h>
+#if defined __SSP__ || defined __SSP_ALL__
+#error "file must not be compiled with stack protection enabled on it. Use -fno-stack-protector"
#endif
-#include <stdio.h>
-#include <string.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <signal.h>
-#include <sys/types.h>
-#include <sys/un.h>
-#include <sys/syslog.h>
-#include <sys/time.h>
-#include <sys/sysctl.h>
-
#ifdef __PROPOLICE_BLOCK_SEGV__
-#define SSP_SIGTYPE SIGSEGV
-#elif __PROPOLICE_BLOCK_KILL__
-#define SSP_SIGTYPE SIGKILL
+# define SSP_SIGTYPE SIGSEGV
#else
-#define SSP_SIGTYPE SIGABRT
+# define SSP_SIGTYPE SIGABRT
#endif
-unsigned long __guard = 0UL;
-
-void __guard_setup(void)
-{
- size_t size;
- struct timeval tv;
-
-#ifdef HAVE_DEV_ERANDOM
- int mib[3];
-#endif
-
- if (__guard != 0UL)
- return;
-
-#ifndef __SSP_QUICK_CANARY__
-#ifdef HAVE_DEV_ERANDOM
- /* Random is another depth in Linux, hence an array of 3. */
- mib[0] = CTL_KERN;
- mib[1] = KERN_RANDOM;
- mib[2] = RANDOM_ERANDOM;
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#if defined __UCLIBC_HAS_SYSLOG__
+#include <sys/syslog.h>
- size = sizeof(unsigned long);
- if (__sysctl(mib, 3, &__guard, &size, NULL, 0) != (-1))
- if (__guard != 0UL)
- return;
+libc_hidden_proto(openlog)
+libc_hidden_proto(syslog)
+libc_hidden_proto(closelog)
#endif
- /*
- * Attempt to open kernel pseudo random device if one exists before
- * opening urandom to avoid system entropy depletion.
- */
- {
- int fd;
-
-#ifdef HAVE_DEV_ERANDOM
- if ((fd = open("/dev/erandom", O_RDONLY)) == (-1))
-#endif
- fd = open("/dev/urandom", O_RDONLY);
- if (fd != (-1)) {
- size = read(fd, (char *) &__guard, sizeof(__guard));
- close(fd);
- if (size == sizeof(__guard))
- return;
- }
- }
-#endif
- /* If sysctl was unsuccessful, use the "terminator canary". */
- __guard = 0xFF0A0D00UL;
-
- /* Everything failed? Or we are using a weakened model of the
- * terminator canary */
- gettimeofday(&tv, NULL);
- __guard ^= tv.tv_usec ^ tv.tv_sec;
-}
+/* libc_hidden_proto(sigaction) */
+libc_hidden_proto(sigfillset)
+libc_hidden_proto(sigdelset)
+/* libc_hidden_proto(sigprocmask) */
+/* libc_hidden_proto(write) */
+libc_hidden_proto(kill)
+/* libc_hidden_proto(getpid) */
+/* libc_hidden_proto(_exit) */
-void __stack_smash_handler(char func[], int damaged)
+static void block_signals(void)
{
- extern char *__progname;
- const char message[] = ": stack smashing attack in function ";
struct sigaction sa;
sigset_t mask;
sigfillset(&mask);
sigdelset(&mask, SSP_SIGTYPE); /* Block all signal handlers */
- sigprocmask(SIG_BLOCK, &mask, NULL); /* except SIGABRT */
-
- /* print error message to stderr and syslog */
- fprintf(stderr, "%s%s%s()\n", __progname, message, func);
- syslog(LOG_INFO, "%s%s%s()", __progname, message, func);
+ sigprocmask(SIG_BLOCK, &mask, NULL); /* except SSP_SIGTYPE */
- /* Make sure the default handler is associated with the our signal handler */
+ /* Make the default handler associated with the signal handler */
memset(&sa, 0, sizeof(struct sigaction));
sigfillset(&sa.sa_mask); /* Block all signals */
sa.sa_flags = 0;
sa.sa_handler = SIG_DFL;
sigaction(SSP_SIGTYPE, &sa, NULL);
+}
+
+static void ssp_write(int fd, const char *msg1, const char *msg2, const char *msg3) __cold
+{
+ write(fd, msg1, strlen(msg1));
+ write(fd, msg2, strlen(msg2));
+ write(fd, msg3, strlen(msg3));
+ write(fd, "()\n", 3);
+#if defined __UCLIBC_HAS_SYSLOG__
+ openlog("ssp", LOG_CONS | LOG_PID, LOG_USER);
+ syslog(LOG_INFO, "%s%s%s()", msg1, msg2, msg3);
+ closelog();
+#endif
+}
+
+static attribute_noreturn void terminate(void)
+{
(void) kill(getpid(), SSP_SIGTYPE);
_exit(127);
}
+
+void __stack_smash_handler(char func[], int damaged __attribute__ ((unused))) attribute_noreturn __cold;
+void __stack_smash_handler(char func[], int damaged)
+{
+ static const char message[] = ": stack smashing attack in function ";
+
+ block_signals();
+
+ ssp_write(STDERR_FILENO, __uclibc_progname, message, func);
+
+ /* The loop is added only to keep gcc happy. */
+ while(1)
+ terminate();
+}
+
+void __stack_chk_fail(void) attribute_noreturn __cold;
+void __stack_chk_fail(void)
+{
+ static const char msg1[] = "stack smashing detected: ";
+ static const char msg3[] = " terminated";
+
+ block_signals();
+
+ ssp_write(STDERR_FILENO, msg1, __uclibc_progname, msg3);
+
+ /* The loop is added only to keep gcc happy. */
+ while(1)
+ terminate();
+}
+
+#if 0
+void __chk_fail(void) attribute_noreturn;
+void __chk_fail(void)
+{
+ static const char msg1[] = "buffer overflow detected: ";
+ static const char msg3[] = " terminated";
+
+ block_signals();
+
+ ssp_write(STDERR_FILENO, msg1, __uclibc_progname, msg3);
+
+ /* The loop is added only to keep gcc happy. */
+ while(1)
+ terminate();
+}
+#endif
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