From 4b692dffb95ac4812b161eb6a16113d7e824982e Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 19 Oct 2017 08:28:09 -0700
Subject: [PATCH 73/90] x86-64: Don't set GLRO(dl_platform) to NULL [BZ #22299]

Since ld.so expands $PLATFORM with GLRO(dl_platform), don't set
GLRO(dl_platform) to NULL.

	[BZ #22299]
	* sysdeps/x86/cpu-features.c (init_cpu_features): Don't set
	GLRO(dl_platform) to NULL.
	* sysdeps/x86_64/Makefile (tests): Add tst-platform-1.
	(modules-names): Add tst-platformmod-1 and
	x86_64/tst-platformmod-2.
	(CFLAGS-tst-platform-1.c): New.
	(CFLAGS-tst-platformmod-1.c): Likewise.
	(CFLAGS-tst-platformmod-2.c): Likewise.
	(LDFLAGS-tst-platformmod-2.so): Likewise.
	($(objpfx)tst-platform-1): Likewise.
	($(objpfx)tst-platform-1.out): Likewise.
	(tst-platform-1-ENV): Likewise.
	($(objpfx)x86_64/tst-platformmod-2.os): Likewise.
	* sysdeps/x86_64/tst-platform-1.c: New file.
	* sysdeps/x86_64/tst-platformmod-1.c: Likewise.
	* sysdeps/x86_64/tst-platformmod-2.c: Likewise.

(cherry picked from commit 4d916f0f12b230f49967797f98b2b613c734a047)

diff --git a/ChangeLog b/ChangeLog
index 366eaba804..26ebb2e7c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,24 @@
+2017-10-26  Valery Reznic <valery_reznic@yahoo.com>
+	    H.J. Lu  <hongjiu.lu@intel.com>
+
+	[BZ #22299]
+	* sysdeps/x86/cpu-features.c (init_cpu_features): Don't set
+	GLRO(dl_platform) to NULL.
+	* sysdeps/x86_64/Makefile (tests): Add tst-platform-1.
+	(modules-names): Add tst-platformmod-1 and
+	x86_64/tst-platformmod-2.
+	(CFLAGS-tst-platform-1.c): New.
+	(CFLAGS-tst-platformmod-1.c): Likewise.
+	(CFLAGS-tst-platformmod-2.c): Likewise.
+	(LDFLAGS-tst-platformmod-2.so): Likewise.
+	($(objpfx)tst-platform-1): Likewise.
+	($(objpfx)tst-platform-1.out): Likewise.
+	(tst-platform-1-ENV): Likewise.
+	($(objpfx)x86_64/tst-platformmod-2.os): Likewise.
+	* sysdeps/x86_64/tst-platform-1.c: New file.
+	* sysdeps/x86_64/tst-platformmod-1.c: Likewise.
+	* sysdeps/x86_64/tst-platformmod-2.c: Likewise.
+
 2017-10-23  Alexey Makhalov  <amakhalov@vmware.com>
 
 	* elf/dl-tunables.c (do_tunable_update_val): Range checking fix.
diff --git a/NEWS b/NEWS
index cd6636d0e0..ea1c1f1c04 100644
--- a/NEWS
+++ b/NEWS
@@ -47,6 +47,7 @@ The following bugs are resolved with this release:
   [22225] math: nearbyint arithmetic moved before feholdexcept
   [22235] Add C++ versions of iscanonical for ldbl-96 and ldbl-128ibm
   [22296] Let signbit use the builtin in C++ mode with gcc < 6.x
+  [22299] x86-64: Don't set GLRO(dl_platform) to NULL
   [22320] glob: Fix one-byte overflow (CVE-2017-15670)
   [22321] sysconf: Fix missing definition of UIO_MAXIOV on Linux
   [22322] libc: [mips64] wrong bits/long-double.h installed
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 3a5c3e8bfd..87aaa8683c 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -389,7 +389,6 @@ no_cpuid:
 #endif
 
   /* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86.  */
-  GLRO(dl_platform) = NULL;
 #if !HAVE_TUNABLES && defined SHARED
   /* The glibc.tune.hwcap_mask tunable is initialized already, so no need to do
      this.  */
@@ -400,13 +399,15 @@ no_cpuid:
   GLRO(dl_hwcap) = HWCAP_X86_64;
   if (cpu_features->kind == arch_kind_intel)
     {
+      const char *platform = NULL;
+
       if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable)
 	  && CPU_FEATURES_CPU_P (cpu_features, AVX512CD))
 	{
 	  if (CPU_FEATURES_CPU_P (cpu_features, AVX512ER))
 	    {
 	      if (CPU_FEATURES_CPU_P (cpu_features, AVX512PF))
-		GLRO(dl_platform) = "xeon_phi";
+		platform = "xeon_phi";
 	    }
 	  else
 	    {
@@ -417,7 +418,7 @@ no_cpuid:
 	    }
 	}
 
-      if (GLRO(dl_platform) == NULL
+      if (platform == NULL
 	  && CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
 	  && CPU_FEATURES_ARCH_P (cpu_features, FMA_Usable)
 	  && CPU_FEATURES_CPU_P (cpu_features, BMI1)
@@ -425,7 +426,10 @@ no_cpuid:
 	  && CPU_FEATURES_CPU_P (cpu_features, LZCNT)
 	  && CPU_FEATURES_CPU_P (cpu_features, MOVBE)
 	  && CPU_FEATURES_CPU_P (cpu_features, POPCNT))
-	GLRO(dl_platform) = "haswell";
+	platform = "haswell";
+
+      if (platform != NULL)
+	GLRO(dl_platform) = platform;
     }
 #else
   GLRO(dl_hwcap) = 0;
diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
index cb4e63897c..a7e26ac485 100644
--- a/sysdeps/x86_64/Makefile
+++ b/sysdeps/x86_64/Makefile
@@ -62,6 +62,21 @@ endif
 
 $(objpfx)tst-x86_64-1: $(objpfx)x86_64/tst-x86_64mod-1.so
 
+ifneq (no,$(have-tunables))
+tests += tst-platform-1
+modules-names += tst-platformmod-1 x86_64/tst-platformmod-2
+CFLAGS-tst-platform-1.c = -mno-avx
+CFLAGS-tst-platformmod-1.c = -mno-avx
+CFLAGS-tst-platformmod-2.c = -mno-avx
+LDFLAGS-tst-platformmod-2.so = -Wl,-soname,tst-platformmod-2.so
+$(objpfx)tst-platform-1: $(objpfx)tst-platformmod-1.so
+$(objpfx)tst-platform-1.out: $(objpfx)x86_64/tst-platformmod-2.so
+# Turn off AVX512F_Usable and AVX2_Usable so that GLRO(dl_platform) is
+# always set to x86_64.
+tst-platform-1-ENV = LD_PRELOAD=$(objpfx)\$$PLATFORM/tst-platformmod-2.so \
+	GLIBC_TUNABLES=glibc.tune.hwcaps=-AVX512F_Usable,-AVX2_Usable
+endif
+
 tests += tst-audit3 tst-audit4 tst-audit5 tst-audit6 tst-audit7 \
 	 tst-audit10 tst-sse tst-avx tst-avx512
 test-extras += tst-audit4-aux tst-audit10-aux \
@@ -143,3 +158,8 @@ do-tests-clean common-mostlyclean: tst-x86_64-1-clean
 .PHONY: tst-x86_64-1-clean
 tst-x86_64-1-clean:
 	-rm -rf $(objpfx)x86_64
+
+$(objpfx)x86_64/tst-platformmod-2.os: $(objpfx)tst-platformmod-2.os
+	$(make-target-directory)
+	rm -f $@
+	ln $< $@
diff --git a/sysdeps/x86_64/tst-platform-1.c b/sysdeps/x86_64/tst-platform-1.c
new file mode 100644
index 0000000000..76a02e4b6d
--- /dev/null
+++ b/sysdeps/x86_64/tst-platform-1.c
@@ -0,0 +1,29 @@
+/* Test PRELOAD with $PLATFORM.
+   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/>.  */
+
+#include <stdlib.h>
+
+extern int preload (void);
+
+static int
+do_test (void)
+{
+  return preload () == 0x1234 ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/x86_64/tst-platformmod-1.c b/sysdeps/x86_64/tst-platformmod-1.c
new file mode 100644
index 0000000000..9ef5e2b5be
--- /dev/null
+++ b/sysdeps/x86_64/tst-platformmod-1.c
@@ -0,0 +1,23 @@
+/* Test PRELOAD with $PLATFORM.
+   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/>.  */
+
+int
+preload (void)
+{
+  return 0;
+}
diff --git a/sysdeps/x86_64/tst-platformmod-2.c b/sysdeps/x86_64/tst-platformmod-2.c
new file mode 100644
index 0000000000..d0e5103892
--- /dev/null
+++ b/sysdeps/x86_64/tst-platformmod-2.c
@@ -0,0 +1,23 @@
+/* Test PRELOAD with $PLATFORM.
+   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/>.  */
+
+int
+preload (void)
+{
+  return 0x1234;
+}