From db656fe46926e0e73f16418411d49be15b808da0 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Sat, 12 Nov 2022 23:45:26 +0200
Subject: [PATCH] Implement Stack Smashing Protection

---
 kernel/Makefile     |  3 ++-
 kernel/kernel/ssp.c | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 kernel/kernel/ssp.c

diff --git a/kernel/Makefile b/kernel/Makefile
index 3b876de6..5dbdeeca 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -13,7 +13,7 @@ EXEC_PREFIX?=$(PREFIX)
 BOOTDIR?=$(EXEC_PREFIX)/boot
 INCLUDEDIR?=$(PREFIX)/include
  
-CFLAGS:=$(CFLAGS) -ffreestanding -Wall -Wextra
+CFLAGS:=$(CFLAGS) -fstack-protector -ffreestanding -Wall -Wextra
 CPPFLAGS:=$(CPPFLAGS) -D__is_kernel -Iinclude
 LDFLAGS:=$(LDFLAGS)
 LIBS:=$(LIBS) -nostdlib -lk -lgcc
@@ -30,6 +30,7 @@ LIBS:=$(LIBS) $(KERNEL_ARCH_LIBS)
 KERNEL_OBJS=\
 $(KERNEL_ARCH_OBJS) \
 kernel/kernel.o \
+kernel/ssp.o \
  
 OBJS=\
 $(ARCHDIR)/crti.o \
diff --git a/kernel/kernel/ssp.c b/kernel/kernel/ssp.c
new file mode 100644
index 00000000..02bc8763
--- /dev/null
+++ b/kernel/kernel/ssp.c
@@ -0,0 +1,18 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+ 
+#if UINT32_MAX == UINTPTR_MAX
+#define STACK_CHK_GUARD 0xe2dee396
+#else
+#define STACK_CHK_GUARD 0x595e9fbd94fda766
+#endif
+ 
+uintptr_t __stack_chk_guard = STACK_CHK_GUARD;
+ 
+__attribute__((noreturn))
+void __stack_chk_fail(void)
+{
+	printf("Stack smashing detected\n");
+	abort();
+}
\ No newline at end of file