[PATCH v6 06/14] misc/sys/cdefs.h: Create FORTIFY redirects for internal calls

["Frédéric Bérat" <fberat@redhat.com>]

The __REDIRECT* macros are creating aliases which may lead to unwanted
PLT entries when fortification is enabled.
To prevent these entries, the REDIRECT alias should be set to point to the
existing __GI_* aliases.
This is done transparently by creating a __REDIRECT_FORTIFY* version of
these macros, that can be overwritten internally when necessary.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---
 include/sys/cdefs.h | 14 ++++++++++++++
 misc/sys/cdefs.h    |  8 ++++++++
 2 files changed, 22 insertions(+)

diff --git a/include/sys/cdefs.h b/include/sys/cdefs.h
index 56adb231aa..b84ad34a70 100644
--- a/include/sys/cdefs.h
+++ b/include/sys/cdefs.h
@@ -40,6 +40,20 @@ rtld_hidden_proto (__chk_fail)
 
 #endif
 
+#if defined SHARED
+#if IS_IN (libc) && __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+
+#undef __REDIRECT_FORTIFY
+#define __REDIRECT_FORTIFY(name, proto, alias) \
+  __REDIRECT(name, proto, __GI_##alias)
+
+#undef __REDIRECT_FORTIFY_NTH
+#define __REDIRECT_FORTIFY_NTH(name, proto, alias) \
+  __REDIRECT_NTH(name, proto, __GI_##alias)
+
+#endif
+#endif /* defined SHARED */
+
 #endif /* !defined _ISOMAC */
 
 #endif
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 393d9091d9..90c21e2703 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -268,6 +268,14 @@
 # define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
 
+#ifndef __REDIRECT_FORTIFY
+#define __REDIRECT_FORTIFY __REDIRECT
+#endif
+
+#ifndef __REDIRECT_FORTIFY_NTH
+#define __REDIRECT_FORTIFY_NTH __REDIRECT_NTH
+#endif
+
 /*
 #elif __SOME_OTHER_COMPILER__
 
-- 
2.41.0