[3.13.y-ckt stable] Patch "stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Mon Dec 14 12:12:06 PST 2015


This is a note to let you know that I have just added a patch titled

    stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between architectures

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt32.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 1ccdfa137682b4705bd211dd9e8c17b8c5ce3be3 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook at chromium.org>
Date: Thu, 19 Dec 2013 11:35:58 -0800
Subject: stackprotector: Unify the HAVE_CC_STACKPROTECTOR logic between
 architectures

commit 19952a92037e752f9d3bbbad552d596f9a56e146 upstream.

Instead of duplicating the CC_STACKPROTECTOR Kconfig and
Makefile logic in each architecture, switch to using
HAVE_CC_STACKPROTECTOR and keep everything in one place. This
retains the x86-specific bug verification scripts.

Signed-off-by: Kees Cook <keescook at chromium.org>
Cc: Arjan van de Ven <arjan at linux.intel.com>
Cc: Michal Marek <mmarek at suse.cz>
Cc: Russell King <linux at arm.linux.org.uk>
Cc: Ralf Baechle <ralf at linux-mips.org>
Cc: Paul Mundt <lethal at linux-sh.org>
Cc: James Hogan <james.hogan at imgtec.com>
Cc: Stephen Rothwell <sfr at canb.auug.org.au>
Cc: Shawn Guo <shawn.guo at linaro.org>
Cc: Linus Torvalds <torvalds at linux-foundation.org>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-mips at linux-mips.org
Cc: linux-arch at vger.kernel.org
Link: http://lkml.kernel.org/r/1387481759-14535-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo at kernel.org>
[ kamal: 3.13-stable prereq for
  8779657 stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 Makefile           | 14 +++++++++++---
 arch/Kconfig       | 22 ++++++++++++++++++++++
 arch/arm/Kconfig   | 13 +------------
 arch/arm/Makefile  |  4 ----
 arch/mips/Kconfig  | 14 +-------------
 arch/mips/Makefile |  4 ----
 arch/sh/Kconfig    | 15 +--------------
 arch/sh/Makefile   |  4 ----
 arch/x86/Kconfig   | 17 +----------------
 arch/x86/Makefile  |  8 +++-----
 10 files changed, 40 insertions(+), 75 deletions(-)

diff --git a/Makefile b/Makefile
index 7606094..58a799e 100644
--- a/Makefile
+++ b/Makefile
@@ -597,10 +597,18 @@ ifneq ($(CONFIG_FRAME_WARN),0)
 KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
 endif

-# Force gcc to behave correct even for buggy distributions
-ifndef CONFIG_CC_STACKPROTECTOR
-KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
+# Handle stack protector mode.
+ifdef CONFIG_CC_STACKPROTECTOR
+  stackp-flag := -fstack-protector
+  ifeq ($(call cc-option, $(stackp-flag)),)
+    $(warning Cannot use CONFIG_CC_STACKPROTECTOR: \
+	      -fstack-protector not supported by compiler))
+  endif
+else
+  # Force off for distro compilers that enable stack protector by default.
+  stackp-flag := $(call cc-option, -fno-stack-protector)
 endif
+KBUILD_CFLAGS += $(stackp-flag)

 # This warning generated too much noise in a regular build.
 # Use make W=1 to enable this warning (see scripts/Makefile.build)
diff --git a/arch/Kconfig b/arch/Kconfig
index f1cf895..24e026d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -336,6 +336,28 @@ config SECCOMP_FILTER

 	  See Documentation/prctl/seccomp_filter.txt for details.

+config HAVE_CC_STACKPROTECTOR
+	bool
+	help
+	  An arch should select this symbol if:
+	  - its compiler supports the -fstack-protector option
+	  - it has implemented a stack canary (e.g. __stack_chk_guard)
+
+config CC_STACKPROTECTOR
+	bool "Enable -fstack-protector buffer overflow detection"
+	depends on HAVE_CC_STACKPROTECTOR
+	help
+	  This option turns on the -fstack-protector GCC feature. This
+	  feature puts, at the beginning of functions, a canary value on
+	  the stack just before the return address, and validates
+	  the value just before actually returning.  Stack based buffer
+	  overflows (that need to overwrite this return address) now also
+	  overwrite the canary, which gets detected and the attack is then
+	  neutralized via a kernel panic.
+
+	  This feature requires gcc version 4.2 or above, or a distribution
+	  gcc with the feature backported.
+
 config HAVE_CONTEXT_TRACKING
 	bool
 	help
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b3d400d..5102fd5 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -31,6 +31,7 @@ config ARM
 	select HAVE_BPF_JIT
 	select HAVE_CONTEXT_TRACKING
 	select HAVE_C_RECORDMCOUNT
+	select HAVE_CC_STACKPROTECTOR
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_API_DEBUG
 	select HAVE_DMA_ATTRS
@@ -1859,18 +1860,6 @@ config SECCOMP
 	  and the task is only allowed to execute a few safe syscalls
 	  defined by each seccomp mode.

-config CC_STACKPROTECTOR
-	bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
-	help
-	  This option turns on the -fstack-protector GCC feature. This
-	  feature puts, at the beginning of functions, a canary value on
-	  the stack just before the return address, and validates
-	  the value just before actually returning.  Stack based buffer
-	  overflows (that need to overwrite this return address) now also
-	  overwrite the canary, which gets detected and the attack is then
-	  neutralized via a kernel panic.
-	  This feature requires gcc version 4.2 or above.
-
 config SWIOTLB
 	def_bool y

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 749e88f..bc050dc 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -40,10 +40,6 @@ ifeq ($(CONFIG_FRAME_POINTER),y)
 KBUILD_CFLAGS	+=-fno-omit-frame-pointer -mapcs -mno-sched-prolog
 endif

-ifeq ($(CONFIG_CC_STACKPROTECTOR),y)
-KBUILD_CFLAGS	+=-fstack-protector
-endif
-
 ifeq ($(CONFIG_CPU_BIG_ENDIAN),y)
 KBUILD_CPPFLAGS	+= -mbig-endian
 AS		+= -EB
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 650de39..c93d92b 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -47,6 +47,7 @@ config MIPS
 	select MODULES_USE_ELF_RELA if MODULES && 64BIT
 	select CLONE_BACKWARDS
 	select HAVE_DEBUG_STACKOVERFLOW
+	select HAVE_CC_STACKPROTECTOR

 menu "Machine selection"

@@ -2322,19 +2323,6 @@ config SECCOMP

 	  If unsure, say Y. Only embedded should say N here.

-config CC_STACKPROTECTOR
-	bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
-	help
-	  This option turns on the -fstack-protector GCC feature. This
-	  feature puts, at the beginning of functions, a canary value on
-	  the stack just before the return address, and validates
-	  the value just before actually returning.  Stack based buffer
-	  overflows (that need to overwrite this return address) now also
-	  overwrite the canary, which gets detected and the attack is then
-	  neutralized via a kernel panic.
-
-	  This feature requires gcc version 4.2 or above.
-
 config USE_OF
 	bool
 	select OF
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index de300b9..efe50787 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -232,10 +232,6 @@ bootvars-y	= VMLINUX_LOAD_ADDRESS=$(load-y) \

 LDFLAGS			+= -m $(ld-emul)

-ifdef CONFIG_CC_STACKPROTECTOR
-  KBUILD_CFLAGS += -fstack-protector
-endif
-
 ifdef CONFIG_MIPS
 CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
 	egrep -vw '__GNUC_(|MINOR_|PATCHLEVEL_)_' | \
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 9b0979f..ce29831 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -66,6 +66,7 @@ config SUPERH32
 	select PERF_EVENTS
 	select ARCH_HIBERNATION_POSSIBLE if MMU
 	select SPARSE_IRQ
+	select HAVE_CC_STACKPROTECTOR

 config SUPERH64
 	def_bool ARCH = "sh64"
@@ -695,20 +696,6 @@ config SECCOMP

 	  If unsure, say N.

-config CC_STACKPROTECTOR
-	bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
-	depends on SUPERH32
-	help
-	  This option turns on the -fstack-protector GCC feature. This
-	  feature puts, at the beginning of functions, a canary value on
-	  the stack just before the return address, and validates
-	  the value just before actually returning.  Stack based buffer
-	  overflows (that need to overwrite this return address) now also
-	  overwrite the canary, which gets detected and the attack is then
-	  neutralized via a kernel panic.
-
-	  This feature requires gcc version 4.2 or above.
-
 config SMP
 	bool "Symmetric multi-processing support"
 	depends on SYS_SUPPORTS_SMP
diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index aed701c..d4d16e4 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -199,10 +199,6 @@ ifeq ($(CONFIG_DWARF_UNWINDER),y)
   KBUILD_CFLAGS += -fasynchronous-unwind-tables
 endif

-ifeq ($(CONFIG_CC_STACKPROTECTOR),y)
-  KBUILD_CFLAGS += -fstack-protector
-endif
-
 libs-$(CONFIG_SUPERH32)		:= arch/sh/lib/	$(libs-y)
 libs-$(CONFIG_SUPERH64)		:= arch/sh/lib64/ $(libs-y)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 223080d..250706e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -126,6 +126,7 @@ config X86
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select HAVE_CC_STACKPROTECTOR

 config INSTRUCTION_DECODER
 	def_bool y
@@ -1640,22 +1641,6 @@ config SECCOMP

 	  If unsure, say Y. Only embedded should say N here.

-config CC_STACKPROTECTOR
-	bool "Enable -fstack-protector buffer overflow detection"
-	---help---
-	  This option turns on the -fstack-protector GCC feature. This
-	  feature puts, at the beginning of functions, a canary value on
-	  the stack just before the return address, and validates
-	  the value just before actually returning.  Stack based buffer
-	  overflows (that need to overwrite this return address) now also
-	  overwrite the canary, which gets detected and the attack is then
-	  neutralized via a kernel panic.
-
-	  This feature requires gcc version 4.2 or above, or a distribution
-	  gcc with the feature backported. Older versions are automatically
-	  detected and for those versions, this configuration option is
-	  ignored. (and a warning is printed during bootup)
-
 source kernel/Kconfig.hz

 config KEXEC
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 57d0215..13b22e0 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -89,13 +89,11 @@ else
         KBUILD_CFLAGS += -maccumulate-outgoing-args
 endif

+# Make sure compiler does not have buggy stack-protector support.
 ifdef CONFIG_CC_STACKPROTECTOR
 	cc_has_sp := $(srctree)/scripts/gcc-x86_$(BITS)-has-stack-protector.sh
-        ifeq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
-                stackp-y := -fstack-protector
-                KBUILD_CFLAGS += $(stackp-y)
-        else
-                $(warning stack protector enabled but no compiler support)
+        ifneq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
+                $(warning stack-protector enabled but compiler support broken)
         endif
 endif

--
1.9.1




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