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[PATCH] Extend BIND_NOW to installed programs with --enable-bind-now
- From: Florian Weimer <fweimer at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Wed, 24 Apr 2019 12:18:19 +0200
- Subject: [PATCH] Extend BIND_NOW to installed programs with --enable-bind-now
We received guidance that we should also enable BIND_NOW for installed
programs. I think we can reuse the --enable-bind-now flag for that.
Thanks,
Florian
---
Commit 2d6ab5df3b675e96ee587ae6a8c2ce004c6b1ba9 ("Document and fix
--enable-bind-now [BZ #21015]") extended BIND_NOW to all installed
shared objects. This change also covers installed programs.
2019-04-24 Florian Weimer <fweimer@redhat.com>
Also enable BIND_NOW for programs if --enable-bind-now.
* Makeconfig [$(bind-now)] (link-extra-flags): Add -Wl,-z,now.
(+link-pie): Use $(link-extra-flags).
[! $(build-pie-default)] (+link): Likewise.
* manual/install.texi (Configuring and compiling): Update
--enable-bind-now description.
* INSTALL: Regenerated.
diff --git a/INSTALL b/INSTALL
index ddb9e9018d..e137a71169 100644
--- a/INSTALL
+++ b/INSTALL
@@ -176,10 +176,10 @@ if 'CFLAGS' is specified it must enable optimization. For example:
protection.
'--enable-bind-now'
- Disable lazy binding for installed shared objects. This provides
- additional security hardening because it enables full RELRO and a
- read-only global offset table (GOT), at the cost of slightly
- increased program load times.
+ Disable lazy binding for installed shared objects and programs.
+ This provides additional security hardening because it enables full
+ RELRO and a read-only global offset table (GOT), at the cost of
+ slightly increased program load times.
'--enable-pt_chown'
The file 'pt_chown' is a helper binary for 'grantpt' (*note
diff --git a/Makeconfig b/Makeconfig
index 07007c9459..768df2c3ef 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -398,6 +398,8 @@ endif
# test modules.
ifeq ($(bind-now),yes)
LDFLAGS-lib.so += -Wl,-z,now
+# Extra flags for dynamically linked non-test main programs.
+link-extra-flags += -Wl,-z,now
endif
# Command to run after every final link (executable or shared object).
@@ -426,7 +428,7 @@ ifndef +link-pie
$(link-extra-libs)
+link-pie-after-libc = $(+postctorS) $(+postinit)
define +link-pie
-$(+link-pie-before-libc) $(rtld-LDFLAGS) $(link-libc) $(+link-pie-after-libc)
+$(+link-pie-before-libc) $(rtld-LDFLAGS) $(link-extra-flags) $(link-libc) $(+link-pie-after-libc)
$(call after-link,$@)
endef
define +link-pie-tests
@@ -485,7 +487,7 @@ else # not build-pie-default
$(link-extra-libs)
+link-after-libc = $(+postctor) $(+postinit)
define +link
-$(+link-before-libc) $(rtld-LDFLAGS) $(link-libc) $(+link-after-libc)
+$(+link-before-libc) $(rtld-LDFLAGS) $(link-extra-flags) $(link-libc) $(+link-after-libc)
$(call after-link,$@)
endef
define +link-tests
diff --git a/NEWS b/NEWS
index 63581b3618..792ffb1ec8 100644
--- a/NEWS
+++ b/NEWS
@@ -47,6 +47,9 @@ Deprecated and removed features, and other changes affecting compatibility:
* The obsolete RES_INSECURE1 and RES_INSECURE2 option flags for the DNS stub
resolver have been removed from <resolv.h>.
+* With --enable-bind-now, installed programs are now linked with the
+ BIND_NOW flag.
+
Changes to build and runtime requirements:
* GCC 6.2 or later is required to build the GNU C Library.
diff --git a/manual/install.texi b/manual/install.texi
index a9b8b4974c..29f6b68e25 100644
--- a/manual/install.texi
+++ b/manual/install.texi
@@ -204,10 +204,10 @@ number of routines called directly from assembler are excluded from this
protection.
@item --enable-bind-now
-Disable lazy binding for installed shared objects. This provides
-additional security hardening because it enables full RELRO and a
-read-only global offset table (GOT), at the cost of slightly increased
-program load times.
+Disable lazy binding for installed shared objects and programs. This
+provides additional security hardening because it enables full RELRO
+and a read-only global offset table (GOT), at the cost of slightly
+increased program load times.
@pindex pt_chown
@findex grantpt