New ssp code using syscalls where possible.

Moved guard_setup to __uClibc_main.c, the only place where it is called.
Removed SIGKILL option, not usable with sigaction.

1 files changed, 34 insertions, 103 deletions

diff --git a/libc/sysdeps/linux/common/ssp.c b/libc/sysdeps/linux/common/ssp.c
index 31833cbb9..8d8d89653 100644
--- a/libc/sysdeps/linux/common/ssp.c
+++ b/libc/sysdeps/linux/common/ssp.c
@@ -20,126 +20,57 @@
 # include <config.h>
 #endif
 
-#ifdef __SSP__
-# error ssp.c has to be built w/ -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>
-#ifdef __SSP_USE_ERANDOM__
-# include <sys/sysctl.h>
-#endif
-
-#ifdef __PROPOLICE_BLOCK_SEGV__
-# define SSP_SIGTYPE SIGSEGV
-#elif __PROPOLICE_BLOCK_KILL__
-# define SSP_SIGTYPE SIGKILL
-#else
-# define SSP_SIGTYPE SIGABRT
-#endif
-
-unsigned long __guard = 0UL;
 
-/* Use of __* functions from the rest of glibc here avoids
- * initialisation problems for executables preloaded with
- * libraries that overload the associated standard library
- * functions.
- */
-#ifdef __UCLIBC__
-extern int __libc_open(__const char *file, int flags, ...);
-extern ssize_t __libc_read(int fd, void *buf, size_t count);
-extern int __libc_close(int fd);
-#else
-# define __libc_open(file, flags) __open(file, flags)
-# define __libc_read(fd, buf, count) __read(fd, buf, count)
-# define __libc_close(fd) __close(fd)
-#endif
+#include <ssp-internal.h>
 
-void __guard_setup(void) __attribute__ ((constructor));
-void __guard_setup(void)
+static __always_inline void block_signals(void)
 {
-	size_t size;
-
-	if (__guard != 0UL)
-		return;
+	struct sigaction sa;
+	sigset_t mask;
 
-	/* Start with the "terminator canary". */
-	__guard = 0xFF0A0D00UL;
+	sigfillset(&mask);
 
-#ifndef __SSP_QUICK_CANARY__
-# ifdef __SSP_USE_ERANDOM__
-	{
-		int mib[3];
-		/* Random is another depth in Linux, hence an array of 3. */
-		mib[0] = CTL_KERN;
-		mib[1] = KERN_RANDOM;
-		mib[2] = RANDOM_ERANDOM;
+	sigdelset(&mask, SSP_SIGTYPE);	/* Block all signal handlers */
+	SIGPROCMASK(SIG_BLOCK, &mask, NULL);	/* except SSP_SIGTYPE */
 
-		size = sizeof(unsigned long);
-		if (__sysctl(mib, 3, &__guard, &size, NULL, 0) != (-1))
-			if (__guard != 0UL)
-				return;
-	}
-# endif /* ifdef __SSP_USE_ERANDOM__ */
-	/* 
-	 * Attempt to open kernel pseudo random device if one exists before 
-	 * opening urandom to avoid system entropy depletion.
-	 */
-	{
-		int fd;
+	/* 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);
+}
 
-# ifdef __SSP_USE_ERANDOM__
-		if ((fd = __libc_open("/dev/erandom", O_RDONLY)) == (-1))
-# endif
-			fd = __libc_open("/dev/urandom", O_RDONLY);
-		if (fd != (-1)) {
-			size = __libc_read(fd, (char *) &__guard, sizeof(__guard));
-			__libc_close(fd);
-			if (size == sizeof(__guard))
-				return;
-		}
-	}
-#endif /* ifndef __SSP_QUICK_CANARY__ */
+static __always_inline void ssp_write(int fd, const char *msg1, const char *msg2, const char *msg3)
+{
+	WRITE(fd, msg1, strlen(msg1));
+	WRITE(fd, msg2, strlen(msg2));
+	WRITE(fd, msg3, strlen(msg3));
+	WRITE(fd, "()\n", 3);
+	openlog("ssp", LOG_CONS | LOG_PID, LOG_USER);
+	syslog(LOG_INFO, "%s%s%s()", msg1, msg2, msg3);
+	closelog();
+}
 
-	/* Everything failed? Or we are using a weakened model of the 
-	 * terminator canary */
-	{
-		struct timeval tv;
-		gettimeofday(&tv, NULL);
-		__guard ^= tv.tv_usec ^ tv.tv_sec;
-	}
+static __always_inline void terminate(void)
+{
+	(void) KILL(GETPID(), SSP_SIGTYPE);
+	EXIT(127);
 }
 
-void __stack_smash_handler(char func[], int damaged __attribute__ ((unused)));
-void __stack_smash_handler(char func[], int damaged)
+void __attribute__ ((noreturn)) __stack_smash_handler(char func[], int damaged __attribute__ ((unused)));
+void __attribute__ ((noreturn)) __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 SSP_SIGTYPE */
+	block_signals();
 
-	/* 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);
+	ssp_write(STDERR_FILENO, __progname, message, func);
 
-	/* 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);
-	(void) kill(getpid(), SSP_SIGTYPE);
-	_exit(127);
+	while(1)
+		terminate();
 }