[uClibc-cvs] CVS uClibc/libc/sysdeps/linux/common
CVS User solar
solar at codepoet.org
Thu Nov 11 03:12:38 UTC 2004
Update of /var/cvs/uClibc/libc/sysdeps/linux/common
In directory nail:/tmp/cvs-serv7785
Modified Files:
ssp.c
Log Message:
misc cleanups of __stack_smash_handler() function when ssp support is enabled. syslog() support should now work both inside and outside of chroots. erandom code left in but remains #ifdef out by default. May remove erandom completely in the future for uClibc unless the LFS guys and gals want to keep it.
--- /var/cvs/uClibc/libc/sysdeps/linux/common/ssp.c 2004/01/21 23:27:40 1.2
+++ /var/cvs/uClibc/libc/sysdeps/linux/common/ssp.c 2004/11/11 03:12:37 1.3
@@ -1,97 +1,121 @@
+/*
+ * Distributed under the terms of the GNU General Public License v2
+ * $Header: /var/cvs/uClibc/libc/sysdeps/linux/common/ssp.c,v 1.3 2004/11/11 03:12:37 solar Exp $
+ *
+ * This is a modified version of Hiroaki Etoh's stack smashing routines
+ * implemented for glibc.
+ *
+ * The following people have contributed input to this code.
+ * Ned Ludd - <solar[@]gentoo.org>
+ * Alexander Gabert - <pappy[@]gentoo.org>
+ * The PaX Team - <pageexec[@]freemail.hu>
+ * Peter S. Mazinger - <ps.m[@]gmx.net>
+ * Yoann Vandoorselaere - <yoann[@]prelude-ids.org>
+ * Robert Connolly - <robert[@]linuxfromscratch.org>
+ * Cory Visi <cory at visi.name>
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
-
-#ifdef _POSIX_SOURCE
#include <signal.h>
-#endif
-
-#if defined(HAVE_SYSLOG)
#include <sys/types.h>
-#include <sys/socket.h>
#include <sys/un.h>
-
#include <sys/syslog.h>
-#ifndef _PATH_LOG
-#define _PATH_LOG "/dev/log"
-#endif
+#include <sys/time.h>
+#include <sys/sysctl.h>
+
+#ifdef __PROPOLICE_BLOCK_SEGV__
+#define SSP_SIGTYPE SIGSEGV
+#elif __PROPOLICE_BLOCK_KILL__
+#define SSP_SIGTYPE SIGKILL
+#else
+#define SSP_SIGTYPE SIGABRT
#endif
-long __guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
+unsigned long __guard = 0UL;
-void __guard_setup (void)
+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;
-}
+ size_t size;
+ struct timeval tv;
-void __stack_smash_handler (char func[], int damaged)
-{
-#if defined (__GNU_LIBRARY__)
- extern char * __progname;
+#ifdef HAVE_DEV_ERANDOM
+ int mib[3];
#endif
- const char message[] = ": stack smashing attack in function ";
- int bufsz = 512, len;
- char buf[bufsz];
-#if defined(HAVE_SYSLOG)
- int LogFile;
- struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */
-#endif
-#ifdef _POSIX_SOURCE
- {
- sigset_t mask;
- sigfillset(&mask);
- sigdelset(&mask, SIGABRT); /* Block all signal handlers */
- sigprocmask(SIG_BLOCK, &mask, NULL); /* except SIGABRT */
- }
-#endif
-
- strcpy(buf, "<2>"); len=3; /* send LOG_CRIT */
-#if defined (__GNU_LIBRARY__)
- strncat(buf, __progname, bufsz-len-1); len = strlen(buf);
-#endif
- if (bufsz>len) {strncat(buf, message, bufsz-len-1); len = strlen(buf);}
- if (bufsz>len) {strncat(buf, func, bufsz-len-1); len = strlen(buf);}
- /* print error message */
- write (STDERR_FILENO, buf+3, len-3);
-#if defined(HAVE_SYSLOG)
- if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) != -1) {
-
- /*
- * Send "found" message to the "/dev/log" path
- */
- SyslogAddr.sun_family = AF_UNIX;
- (void)strncpy(SyslogAddr.sun_path, _PATH_LOG,
- sizeof(SyslogAddr.sun_path) - 1);
- SyslogAddr.sun_path[sizeof(SyslogAddr.sun_path) - 1] = '\0';
- sendto(LogFile, buf, len, 0, (struct sockaddr *)&SyslogAddr,
- sizeof(SyslogAddr));
- }
-#endif
-
-#ifdef _POSIX_SOURCE
- { /* Make sure the default handler is associated with SIGABRT */
- struct sigaction sa;
-
- memset(&sa, 0, sizeof(struct sigaction));
- sigfillset(&sa.sa_mask); /* Block all signals */
- sa.sa_flags = 0;
- sa.sa_handler = SIG_DFL;
- sigaction(SIGABRT, &sa, NULL);
- (void)kill(getpid(), SIGABRT);
- }
+
+ 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;
+
+ size = sizeof(unsigned long);
+ if (__sysctl(mib, 3, &__guard, &size, NULL, 0) != (-1))
+ if (__guard != 0UL)
+ return;
+#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
- _exit(127);
+ /* 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;
}
+void __stack_smash_handler(char func[], int damaged)
+{
+ 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(KERN_INFO, "%s%s%s()", __progname, message, func);
+
+ /* Make sure the default handler is associated with the our 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);
+ (void) kill(getpid(), SSP_SIGTYPE);
+ _exit(127);
+}
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