linux/scripts/gcc-x86_32-has-stack-protector.sh

#!/bin/sh

echo "int foo(void) { char X[200]; return 3; }" | $* -S -xc -c -O0 -fstack-protector - -o - 2> /dev/null | grep -q "%gs"
if [ "$?" -eq "0" ] ; then
	echo y
else
	echo n
fi
x86: implement x86_32 stack protector Impact: stack protector for x86_32 Implement stack protector for x86_32. GDT entry 28 is used for it. It's set to point to stack_canary-20 and have the length of 24 bytes. CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs to the stack canary segment on entry. As %gs is otherwise unused by the kernel, the canary can be anywhere. It's defined as a percpu variable. x86_32 exception handlers take register frame on stack directly as struct pt_regs. With -fstack-protector turned on, gcc copies the whole structure after the stack canary and (of course) doesn't copy back on return thus losing all changed. For now, -fno-stack-protector is added to all files which contain those functions. We definitely need something better. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> 2009-02-09 06:17:40 -07:00			`#!/bin/sh`

stackprotector: fix multi-word cross-builds Stackprotector builds were failing if CROSS_COMPILER was more than a single world (such as when distcc was used) - because the check scripts used $1 instead of $*. Signed-off-by: Ingo Molnar <mingo@elte.hu> 2009-02-11 04:17:29 -07:00			`echo "int foo(void) { char X[200]; return 3; }" \| $* -S -xc -c -O0 -fstack-protector - -o - 2> /dev/null \| grep -q "%gs"`
x86: implement x86_32 stack protector Impact: stack protector for x86_32 Implement stack protector for x86_32. GDT entry 28 is used for it. It's set to point to stack_canary-20 and have the length of 24 bytes. CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs to the stack canary segment on entry. As %gs is otherwise unused by the kernel, the canary can be anywhere. It's defined as a percpu variable. x86_32 exception handlers take register frame on stack directly as struct pt_regs. With -fstack-protector turned on, gcc copies the whole structure after the stack canary and (of course) doesn't copy back on return thus losing all changed. For now, -fno-stack-protector is added to all files which contain those functions. We definitely need something better. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> 2009-02-09 06:17:40 -07:00			`if [ "$?" -eq "0" ] ; then`
			`echo y`
			`else`
			`echo n`
			`fi`