svn commit: r357215 - in releng: 11.3/lib/libc/secure 12.0/lib/libc/secure 12.1/lib/libc/secure

[Gordon Tetlow]

Author: gordon
Date: Tue Jan 28 18:53:14 2020
New Revision: 357215
URL: https://svnweb.freebsd.org/changeset/base/357215

Log:
  Fix imprecise ordering of SSP canary initialization
  
  Submitted by:	Kyle Evans
  Approved by:	so
  Security:	FreeBSD-EN-20:01.ssp

Modified:
  releng/11.3/lib/libc/secure/stack_protector.c
  releng/12.0/lib/libc/secure/stack_protector.c
  releng/12.1/lib/libc/secure/stack_protector.c

Modified: releng/11.3/lib/libc/secure/stack_protector.c
==============================================================================
--- releng/11.3/lib/libc/secure/stack_protector.c	Tue Jan 28 18:42:06 2020	(r357214)
+++ releng/11.3/lib/libc/secure/stack_protector.c	Tue Jan 28 18:53:14 2020	(r357215)
@@ -40,11 +40,29 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 #include "libc_private.h"
 
+/*
+ * We give __guard_setup a defined priority early on so that statically linked
+ * applications have a defined priority at which __stack_chk_guard will be
+ * getting initialized.  This will not matter to most applications, because
+ * they're either not usually statically linked or they simply don't do things
+ * in constructors that would be adversely affected by their positioning with
+ * respect to this initialization.
+ *
+ * This conditional should be removed when GCC 4.2 is removed.
+ */
+#if __has_attribute(__constructor__) || __GNUC_PREREQ__(4, 3)
+#define	_GUARD_SETUP_CTOR_ATTR	 \
+    __attribute__((__constructor__ (200), __used__));
+#else
+#define	_GUARD_SETUP_CTOR_ATTR	\
+    __attribute__((__constructor__, __used__));
+#endif
+
 extern int __sysctl(const int *name, u_int namelen, void *oldp,
     size_t *oldlenp, void *newp, size_t newlen);
 
 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
-static void __guard_setup(void) __attribute__((__constructor__, __used__));
+static void __guard_setup(void) _GUARD_SETUP_CTOR_ATTR;
 static void __fail(const char *);
 void __stack_chk_fail(void);
 void __chk_fail(void);

Modified: releng/12.0/lib/libc/secure/stack_protector.c
==============================================================================
--- releng/12.0/lib/libc/secure/stack_protector.c	Tue Jan 28 18:42:06 2020	(r357214)
+++ releng/12.0/lib/libc/secure/stack_protector.c	Tue Jan 28 18:53:14 2020	(r357215)
@@ -40,11 +40,29 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 #include "libc_private.h"
 
+/*
+ * We give __guard_setup a defined priority early on so that statically linked
+ * applications have a defined priority at which __stack_chk_guard will be
+ * getting initialized.  This will not matter to most applications, because
+ * they're either not usually statically linked or they simply don't do things
+ * in constructors that would be adversely affected by their positioning with
+ * respect to this initialization.
+ *
+ * This conditional should be removed when GCC 4.2 is removed.
+ */
+#if __has_attribute(__constructor__) || __GNUC_PREREQ__(4, 3)
+#define	_GUARD_SETUP_CTOR_ATTR	 \
+    __attribute__((__constructor__ (200), __used__));
+#else
+#define	_GUARD_SETUP_CTOR_ATTR	\
+    __attribute__((__constructor__, __used__));
+#endif
+
 extern int __sysctl(const int *name, u_int namelen, void *oldp,
     size_t *oldlenp, void *newp, size_t newlen);
 
 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
-static void __guard_setup(void) __attribute__((__constructor__, __used__));
+static void __guard_setup(void) _GUARD_SETUP_CTOR_ATTR;
 static void __fail(const char *);
 void __stack_chk_fail(void);
 void __chk_fail(void);

Modified: releng/12.1/lib/libc/secure/stack_protector.c
==============================================================================
--- releng/12.1/lib/libc/secure/stack_protector.c	Tue Jan 28 18:42:06 2020	(r357214)
+++ releng/12.1/lib/libc/secure/stack_protector.c	Tue Jan 28 18:53:14 2020	(r357215)
@@ -40,11 +40,29 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 #include "libc_private.h"
 
+/*
+ * We give __guard_setup a defined priority early on so that statically linked
+ * applications have a defined priority at which __stack_chk_guard will be
+ * getting initialized.  This will not matter to most applications, because
+ * they're either not usually statically linked or they simply don't do things
+ * in constructors that would be adversely affected by their positioning with
+ * respect to this initialization.
+ *
+ * This conditional should be removed when GCC 4.2 is removed.
+ */
+#if __has_attribute(__constructor__) || __GNUC_PREREQ__(4, 3)
+#define	_GUARD_SETUP_CTOR_ATTR	 \
+    __attribute__((__constructor__ (200), __used__));
+#else
+#define	_GUARD_SETUP_CTOR_ATTR	\
+    __attribute__((__constructor__, __used__));
+#endif
+
 extern int __sysctl(const int *name, u_int namelen, void *oldp,
     size_t *oldlenp, void *newp, size_t newlen);
 
 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
-static void __guard_setup(void) __attribute__((__constructor__, __used__));
+static void __guard_setup(void) _GUARD_SETUP_CTOR_ATTR;
 static void __fail(const char *);
 void __stack_chk_fail(void);
 void __chk_fail(void);