Libc-1081.1.3.tar.gz

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

diff --git a/sys/OpenBSD/stack_protector.c b/sys/OpenBSD/stack_protector.c
index 368e365b02fb74d86ee143cd6aac7e000fa3ff00..988d8edc1f8090f7737a642fcfac99ae327f6d12 100644 (file)
--- a/sys/OpenBSD/stack_protector.c
+++ b/sys/OpenBSD/stack_protector.c
@@ -1,3 +1,5 @@
+/*     $OpenBSD: stack_protector.c,v 1.10 2006/03/31 05:34:44 deraadt Exp $    */
+
 /*
  * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
  * All rights reserved.
@@ -25,51 +27,115 @@
  *
  */
 
-#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>
+#include <signal.h>
+#include <string.h>
+#include <stdlib.h>
+#include <asl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <CrashReporterClient.h>
+#include "libproc.h"
+#include "_simple.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)));
+#define        GUARD_MAX 8
+long __stack_chk_guard[GUARD_MAX] = {0, 0, 0, 0, 0, 0, 0, 0};
+void __abort(void) __dead2;
+void __guard_setup(const char *apple[]) __attribute__ ((visibility ("hidden")));
+void __stack_chk_fail(void);
 
 static void
-__guard_setup(void)
+__guard_from_kernel(const char *str)
 {
-  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;
+       unsigned long long val;
+       char tmp[20], *p;
+       int idx = 0;
+
+       /* Skip over the 'stack_guard=' key to the list of values */
+       str = strchr(str, '=');
+       if (str == NULL)
+               return;
+       str++;
+
+       while (str && idx < GUARD_MAX) {
+               /*
+                * Pull the next numeric string out of the list and convert it to
+                * a real number.
+                */
+               strlcpy(tmp, str, 20);
+               p = strchr(tmp, ',');
+               if (p)
+                       *p = '\0';
+               val = strtoull(tmp, NULL, 0);
+               __stack_chk_guard[idx] = (long)(val & ((unsigned long) -1));
+               idx++;
+               if ((str = strchr(str, ',')) != NULL)
+                       str++;
+       }
 }
 
 void
-__stack_smash_handler(char func[], int damaged)
+__guard_setup(const char *apple[])
 {
-  const char message[] = "stack overflow in function %s";
-  struct sigaction sa;
+       int fd;
+       size_t len;
+       const char **p;
+
+       if (__stack_chk_guard[0] != 0)
+               return;
+
+       for (p = apple; p && *p; p++) {
+               if (strstr(*p, "stack_guard") == *p) {
+                       __guard_from_kernel(*p);
+                       bzero((void*)*p, strlen(*p));
+                       if (__stack_chk_guard[0] != 0) {
+                               return;
+                       }
+               }
+       }
 
-  /* this may fail on a chroot jail, though luck */
-  syslog(LOG_CRIT, message, func);
+       fd = open ("/dev/urandom", 0);
+       if (fd != -1) {
+               len = read (fd, (char*)&__stack_chk_guard, sizeof(__stack_chk_guard));
+               close(fd);
+               if (len == sizeof(__stack_chk_guard) && 
+                    *__stack_chk_guard != 0)
+                       return;
+       }
 
-  bzero(&sa, sizeof(struct sigaction));
-  sigemptyset(&sa.sa_mask);
-  sa.sa_flags = 0;
-  sa.sa_handler = SIG_DFL;
-  sigaction(SIGABRT, &sa, NULL);
+       /* If If a random generator can't be used, the protector switches the guard
+           to the "terminator canary" */
+       ((unsigned char *)__stack_chk_guard)[0] = 0;
+       ((unsigned char *)__stack_chk_guard)[1] = 0;
+       ((unsigned char *)__stack_chk_guard)[2] = '\n';
+       ((unsigned char *)__stack_chk_guard)[3] = 255;
+}
+
+#define STACKOVERFLOW  "] stack overflow"
+
+void
+__stack_chk_fail()
+{
+       char n[16]; // bigger than will hold the digits in a pid_t
+       char *np;
+       int pid = getpid();
+       char message[sizeof(n) + sizeof(STACKOVERFLOW)] = "[";
+       char prog[2*MAXCOMLEN+1] = {0};
 
-  kill(getpid(), SIGABRT);
+       proc_name(pid, prog, 2*MAXCOMLEN);
+       prog[2*MAXCOMLEN] = 0;
+       np = n + sizeof(n);
+       *--np = 0;
+       while(pid > 0) {
+           *--np = (pid % 10) + '0';
+           pid /= 10;
+       }
+       strlcat(message, np, sizeof(message));
+       strlcat(message, STACKOVERFLOW, sizeof(message));
+       /* This may fail on a chroot jail... */
+       _simple_asl_log_prog(ASL_LEVEL_CRIT, "user", message, prog);
 
-  _exit(127);
+       CRSetCrashLogMessage(message);
+       __abort();
 }