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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/configs
parent2bc2f688fdf8808de4f36be563ccdb0bde7c0c54 (diff)
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/configs')
-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