Use fortify macros for b{zero,copy} along decl from strings.h

As described in BZ#20558, bzero and bcopy declaration can only benefit
from fortified macros when decl came from string.h and when __USE_MISC
is defined (default behaviour).

This is due no standard includes those functions in string.h, so they
are only declared if __USE_MISC is defined (as pointed out in comment 4).
However fortification should be orthogona to other features test macros,
i.e, any function should be fortified if that function is declared.

To fix this behavior, the patch moved the bzero, bcopy, and
__explicit_bzero_chk to a common header (string/bits/strings_fortified.h)
and explicit fortified inclusion macros similar to string.h is added
on strings.h.  This allows to get fortified declarions by only including
strings.h.

Checked on x86_64-linux-gnu and along on a bootstrap installation to check
if the fortified are correctly triggered with example from bug report.

	[BZ #20558]
	* string/bits/string3.h [__USE_MISC] (bcopy): Move to
	strings_fortified.h.
	[__USE_MISC] (bzero): Likewise.
	[__USE_MISC] (explicit_bzero): Likewise.
	* string/strings.h: Include strings_fortified.h.
	* string/Makefile (headers): Add strings_fortified.h.
	* string/bits/strings_fortified.h: New file.
	* include/bits/strings_fortified.h: Likewise.

diff --git a/ChangeLog b/ChangeLog
index 88f9f068f4744e3b4ff879110f01d5170fb75bd1..c67476fca5ffdf9a7577f4309cc50633065ff430 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2017-01-05  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+
+       [BZ #20558]
+       * string/bits/string3.h [__USE_MISC] (bcopy): Move to
+       strings_fortified.h.
+       [__USE_MISC] (bzero): Likewise.
+       [__USE_MISC] (explicit_bzero): Likewise.
+       * string/strings.h: Include strings_fortified.h.
+       * string/Makefile (headers): Add strings_fortified.h.
+       * string/bits/strings_fortified.h: New file.
+       * include/bits/strings_fortified.h: Likewise.
+
 2017-01-05  Joseph Myers  <joseph@codesourcery.com>
 
        * elf/tst-tls13.c (TIMEOUT): Remove.

diff --git a/include/bits/strings_fortified.h b/include/bits/strings_fortified.h
new file mode 100644 (file)
index 0000000..77219c1
--- /dev/null
+++ b/include/bits/strings_fortified.h
@@ -0,0 +1 @@
+#include <string/bits/strings_fortified.h>

diff --git a/string/Makefile b/string/Makefile
index aaa371f6b6dddd084157365c2a845124ca50d1a7..04e9da951ebd3ea030ae4f67b8b0e699734461e1 100644 (file)
--- a/string/Makefile
+++ b/string/Makefile
@@ -24,7 +24,8 @@ include ../Makeconfig
 
 headers        := string.h strings.h memory.h endian.h bits/endian.h \
           argz.h envz.h byteswap.h bits/byteswap.h bits/byteswap-16.h \
-          bits/string.h bits/string2.h bits/string3.h
+          bits/string.h bits/string2.h bits/string3.h \
+          bits/strings_fortified.h
 
 routines       := strcat strchr strcmp strcoll strcpy strcspn          \
                   strverscmp strdup strndup                            \

diff --git a/string/bits/string3.h b/string/bits/string3.h
index fe0c161390e02c204cac2694c81310ec76744925..0b0a37744abee5abb1a6810cfdbd976c64c106b9 100644 (file)
--- a/string/bits/string3.h
+++ b/string/bits/string3.h
@@ -91,26 +91,7 @@ __NTH (memset (void *__dest, int __ch, size_t __len))
 }
 
 #ifdef __USE_MISC
-__fortify_function void
-__NTH (bcopy (const void *__src, void *__dest, size_t __len))
-{
-  (void) __builtin___memmove_chk (__dest, __src, __len, __bos0 (__dest));
-}
-
-__fortify_function void
-__NTH (bzero (void *__dest, size_t __len))
-{
-  (void) __builtin___memset_chk (__dest, '\0', __len, __bos0 (__dest));
-}
-
-void __explicit_bzero_chk (void *__dest, size_t __len, size_t __destlen)
-  __THROW __nonnull ((1));
-
-__fortify_function void
-__NTH (explicit_bzero (void *__dest, size_t __len))
-{
-  __explicit_bzero_chk (__dest, __len, __bos0 (__dest));
-}
+# include <bits/strings_fortified.h>
 #endif
 
 __fortify_function char *

diff --git a/string/bits/strings_fortified.h b/string/bits/strings_fortified.h
new file mode 100644 (file)
index 0000000..fd396f9
--- /dev/null
+++ b/string/bits/strings_fortified.h
@@ -0,0 +1,43 @@
+/* Fortify macros for strings.h functions.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef __STRINGS_FORTIFIED
+# define __STRINGS_FORTIFIED 1
+
+__fortify_function void
+__NTH (bcopy (const void *__src, void *__dest, size_t __len))
+{
+  (void) __builtin___memmove_chk (__dest, __src, __len, __bos0 (__dest));
+}
+
+__fortify_function void
+__NTH (bzero (void *__dest, size_t __len))
+{
+  (void) __builtin___memset_chk (__dest, '\0', __len, __bos0 (__dest));
+}
+
+void __explicit_bzero_chk (void *__dest, size_t __len, size_t __destlen)
+  __THROW __nonnull ((1));
+
+__fortify_function void
+__NTH (explicit_bzero (void *__dest, size_t __len))
+{
+  __explicit_bzero_chk (__dest, __len, __bos0 (__dest));
+}
+
+#endif

diff --git a/string/strings.h b/string/strings.h
index ece21c8c7e716ceafe4ca448fecbf3d575c87fa1..69b75b1219d191c22038bf91ce08747b67f94d51 100644 (file)
--- a/string/strings.h
+++ b/string/strings.h
@@ -136,4 +136,12 @@ __END_DECLS
 
 #endif /* string.h  */
 
+#if __GNUC_PREREQ (3,4) && __USE_FORTIFY_LEVEL > 0 \
+    && defined __fortify_function
+/* Functions with security checks.  */
+# if defined __USE_MISC || !defined __USE_XOPEN2K8
+#  include <bits/strings_fortified.h>
+# endif
+#endif
+
 #endif /* strings.h  */