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authorKees Cook <keescook@chromium.org>2018-02-06 15:37:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:44 -0800
commit2bc2f688fdf8808de4f36be563ccdb0bde7c0c54 (patch)
tree7a3be72336e99a09110442813a37e8b571942f71
parent2b8383927525d6281cbad1cc70a83d2319eeae47 (diff)
Makefile: move stack-protector availability out of Kconfig
Various portions of the kernel, especially per-architecture pieces, need to know if the compiler is building with the stack protector. This was done in the arch/Kconfig with 'select', but this doesn't allow a way to do auto-detected compiler support. In preparation for creating an on-if-available default, move the logic for the definition of CONFIG_CC_STACKPROTECTOR into the Makefile. Link: http://lkml.kernel.org/r/1510076320-69931-3-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Makefile6
-rw-r--r--arch/Kconfig8
-rw-r--r--arch/x86/Kconfig2
3 files changed, 6 insertions, 10 deletions
diff --git a/Makefile b/Makefile
index 20b1aa928d78..f0f934097f64 100644
--- a/Makefile
+++ b/Makefile
@@ -693,7 +693,7 @@ else
endif
endif
# Find arch-specific stack protector compiler sanity-checking script.
-ifdef CONFIG_CC_STACKPROTECTOR
+ifdef stackp-name
stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh
stackp-check := $(wildcard $(stackp-path))
# If the wildcard test matches a test script, run it to check functionality.
@@ -702,6 +702,10 @@ ifdef CONFIG_CC_STACKPROTECTOR
stackp-broken := y
endif
endif
+ ifndef stackp-broken
+ # If the stack protector is functional, enable code that depends on it.
+ KBUILD_CPPFLAGS += -DCONFIG_CC_STACKPROTECTOR
+ endif
endif
KBUILD_CFLAGS += $(stackp-flag)
diff --git a/arch/Kconfig b/arch/Kconfig
index 467dfa35bf96..9330a9d79dc3 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -538,12 +538,6 @@ config HAVE_CC_STACKPROTECTOR
- its compiler supports the -fstack-protector option
- it has implemented a stack canary (e.g. __stack_chk_guard)
-config CC_STACKPROTECTOR
- def_bool n
- help
- Set when a stack-protector mode is enabled, so that the build
- can enable kernel-side support for the GCC feature.
-
choice
prompt "Stack Protector buffer overflow detection"
depends on HAVE_CC_STACKPROTECTOR
@@ -564,7 +558,6 @@ config CC_STACKPROTECTOR_NONE
config CC_STACKPROTECTOR_REGULAR
bool "Regular"
- select CC_STACKPROTECTOR
help
Functions will have the stack-protector canary logic added if they
have an 8-byte or larger character array on the stack.
@@ -578,7 +571,6 @@ config CC_STACKPROTECTOR_REGULAR
config CC_STACKPROTECTOR_STRONG
bool "Strong"
- select CC_STACKPROTECTOR
help
Functions will have the stack-protector canary logic added in any
of the following conditions:
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b0771ceabb4b..d9878f1f3bac 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -322,7 +322,7 @@ config X86_64_SMP
config X86_32_LAZY_GS
def_bool y
- depends on X86_32 && !CC_STACKPROTECTOR
+ depends on X86_32 && CC_STACKPROTECTOR_NONE
config ARCH_SUPPORTS_UPROBES
def_bool y