summary refs log tree commit diff
path: root/kernel
diff options
context:
space:
mode:
authorKees Cook <keescook@chromium.org>2018-02-06 15:37:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:44 -0800
commit44c6dc940b190cf22b044a784f3e00a7e7f08b2f (patch)
tree6aa4149ad96786c80fa9d7b046d26a373d911093 /kernel
parent2bc2f688fdf8808de4f36be563ccdb0bde7c0c54 (diff)
downloadlinux-44c6dc940b190cf22b044a784f3e00a7e7f08b2f.tar.gz
Makefile: introduce CONFIG_CC_STACKPROTECTOR_AUTO
Nearly all modern compilers support a stack-protector option, and nearly
all modern distributions enable the kernel stack-protector, so enabling
this by default in kernel builds would make sense.  However, Kconfig does
not have knowledge of available compiler features, so it isn't safe to
force on, as this would unconditionally break builds for the compilers or
architectures that don't have support.  Instead, this introduces a new
option, CONFIG_CC_STACKPROTECTOR_AUTO, which attempts to discover the best
possible stack-protector available, and will allow builds to proceed even
if the compiler doesn't support any stack-protector.

This option is made the default so that kernels built with modern
compilers will be protected-by-default against stack buffer overflows,
avoiding things like the recent BlueBorne attack.  Selection of a specific
stack-protector option remains available, including disabling it.

Additionally, tiny.config is adjusted to use CC_STACKPROTECTOR_NONE, since
that's the option with the least code size (and it used to be the default,
so we have to explicitly choose it there now).

Link: http://lkml.kernel.org/r/1510076320-69931-4-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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/configs/tiny.config4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config
index 7fa0c4ae6394..9bfdffc100da 100644
--- a/kernel/configs/tiny.config
+++ b/kernel/configs/tiny.config
@@ -10,3 +10,7 @@ CONFIG_OPTIMIZE_INLINING=y
 # CONFIG_SLAB is not set
 # CONFIG_SLUB is not set
 CONFIG_SLOB=y
+CONFIG_CC_STACKPROTECTOR_NONE=y
+# CONFIG_CC_STACKPROTECTOR_REGULAR is not set
+# CONFIG_CC_STACKPROTECTOR_STRONG is not set
+# CONFIG_CC_STACKPROTECTOR_AUTO is not set