Libc-391.4.1.tar.gz

[apple/libc.git] / sys / OpenBSD / stack_protector.c

diff --git a/sys/OpenBSD/stack_protector.c b/sys/OpenBSD/stack_protector.c
new file mode 100644 (file)
index 0000000..368e365
--- /dev/null
+++ b/sys/OpenBSD/stack_protector.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#if defined(LIBC_SCCS) && !defined(list)
+static char rcsid[] = "$OpenBSD: stack_protector.c,v 1.3 2002/12/10 08:53:42 etoh Exp $";
+#endif
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <syslog.h>
+
+long __guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
+static void __guard_setup(void) __attribute__ ((constructor));
+void __stack_smash_handler(char func[], int damaged __attribute__((unused)));
+
+static void
+__guard_setup(void)
+{
+  int fd;
+  if (__guard[0]!=0) return;
+  fd = open ("/dev/urandom", 0);
+  if (fd != -1) {
+    ssize_t size = read (fd, (char*)&__guard, sizeof(__guard));
+    close (fd) ;
+    if (size == sizeof(__guard)) return;
+  }
+  /* If a random generator can't be used, the protector switches the guard
+     to the "terminator canary" */
+  ((char*)__guard)[0] = 0; ((char*)__guard)[1] = 0;
+  ((char*)__guard)[2] = '\n'; ((char*)__guard)[3] = 255;
+}
+
+void
+__stack_smash_handler(char func[], int damaged)
+{
+  const char message[] = "stack overflow in function %s";
+  struct sigaction sa;
+
+  /* this may fail on a chroot jail, though luck */
+  syslog(LOG_CRIT, message, func);
+
+  bzero(&sa, sizeof(struct sigaction));
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = 0;
+  sa.sa_handler = SIG_DFL;
+  sigaction(SIGABRT, &sa, NULL);
+
+  kill(getpid(), SIGABRT);
+
+  _exit(127);
+}