[PATCH 7/8] tools/nolibc: i386: add stackprotector support

Willy Tarreau
2023-03-25T15:46:10Z

From: Thomas Weißschuh <linux@weissschuh.net>

Enable the new stackprotector support for i386.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
tools/include/nolibc/arch-i386.h | 7 ++++++-
tools/testing/selftests/nolibc/Makefile | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h
index e8d0cf545bf1..2d98d78fd3f3 100644
--- a/tools/include/nolibc/arch-i386.h
+++ b/tools/include/nolibc/arch-i386.h
@@ -181,6 +181,8 @@ struct sys_stat_struct {
char **environ __attribute__((weak));
const unsigned long *_auxv __attribute__((weak));

+#define __ARCH_SUPPORTS_STACK_PROTECTOR
+
/* startup code */
/*
* i386 System V ABI mandates:
@@ -188,9 +190,12 @@ const unsigned long *_auxv __attribute__((weak));
* 2) The deepest stack frame should be set to zero
*
*/
-void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
+void __attribute__((weak,noreturn,optimize("omit-frame-pointer"),no_stack_protector)) _start(void)
{
__asm__ volatile (
+#ifdef NOLIBC_STACKPROTECTOR
+ "call __stack_chk_init\n" // initialize stack protector
+#endif
"pop %eax\n" // argc (first arg, %eax)
"mov %esp, %ebx\n" // argv[] (second arg, %ebx)
"lea 4(%ebx,%eax,4),%ecx\n" // then a NULL then envp (third arg, %ecx)
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index e516e53775d4..ab99786c1e94 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -79,6 +79,7 @@ endif
CFLAGS_STACKPROTECTOR = -DNOLIBC_STACKPROTECTOR \
$(call cc-option,-mstack-protector-guard=global) \
$(call cc-option,-fstack-protector-all)
+CFLAGS_STKP_i386 = $(CFLAGS_STACKPROTECTOR)
CFLAGS_s390 = -m64
CFLAGS ?= -Os -fno-ident -fno-asynchronous-unwind-tables \
$(call cc-option,-fno-stack-protector) \
--
2.17.5