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-rw-r--r--arch/Kconfig67
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index f1cf895c040f..80bbb8ccd0d1 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -336,6 +336,73 @@ 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
+ 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
+ default CC_STACKPROTECTOR_NONE
+ help
+ This option turns on the "stack-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.
+
+config CC_STACKPROTECTOR_NONE
+ bool "None"
+ help
+ Disable "stack-protector" GCC feature.
+
+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.
+
+ This feature requires gcc version 4.2 or above, or a distribution
+ gcc with the feature backported ("-fstack-protector").
+
+ On an x86 "defconfig" build, this feature adds canary checks to
+ about 3% of all kernel functions, which increases kernel code size
+ by about 0.3%.
+
+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:
+
+ - local variable's address used as part of the right hand side of an
+ assignment or function argument
+ - local variable is an array (or union containing an array),
+ regardless of array type or length
+ - uses register local variables
+
+ This feature requires gcc version 4.9 or above, or a distribution
+ gcc with the feature backported ("-fstack-protector-strong").
+
+ On an x86 "defconfig" build, this feature adds canary checks to
+ about 20% of all kernel functions, which increases the kernel code
+ size by about 2%.
+
+endchoice
+
config HAVE_CONTEXT_TRACKING
bool
help
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