Libc: add stack smashing protection, moved kernel panic from abort to panic function in stdlib

kernel/Makefile

@@ -13,7 +13,7 @@ EXEC_PREFIX?=$(PREFIX)
 BOOTDIR?=$(EXEC_PREFIX)/boot
 INCLUDEDIR?=$(PREFIX)/include
 
-CFLAGS:=$(CFLAGS) -ffreestanding -Wall -Wextra
+CFLAGS:=$(CFLAGS) -ffreestanding -Wall -Wextra -fstack-protector-all
 CPPFLAGS:=$(CPPFLAGS) -D__is_kernel -Iinclude
 LDFLAGS:=$(LDFLAGS)
 LIBS:=$(LIBS) -nostdlib -lk -lgcc

libc/Makefile

@@ -33,6 +33,8 @@ stdio/printf.o \
 stdio/putchar.o \
 stdio/puts.o \
 stdlib/abort.o \
+stdlib/panic.o \
+stdlib/stack_protection.o \
 string/memcmp.o \
 string/memcpy.o \
 string/memmove.o \

libc/include/stdlib.h

@@ -9,6 +9,7 @@ extern "C" {
 
 __attribute__((__noreturn__))
 void abort(void);
+void panic(char *panic_msg);
 
 #ifdef __cplusplus
 }

libc/stdlib/abort.c

@@ -5,11 +5,9 @@ __attribute__((__noreturn__))
 void abort(void) {
 #if defined(__is_libk)
 	// TODO: Add proper kernel panic.
-	printf("kernel: panic: abort()\n");
+	panic("abort()\n");
 #else
 	// TODO: Abnormally terminate the process as if by SIGABRT.
 	printf("abort()\n");
 #endif
-	while (1) { }
-	__builtin_unreachable();
 }

libc/stdlib/panic.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+__attribute__((__noreturn__))
+void panic(char *panic_msg) {
+#if defined(__is_libk)
+	// TODO: Add proper kernel panic.
+  printf("kernel: panic: %s\n", panic_msg);
+#endif
+	while (1) { }
+	__builtin_unreachable();
+}

libc/stdlib/stack_protection.c

@@ -0,0 +1,20 @@
+#include <stdint.h>
+#include <stdlib.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)
+{
+#if __STDC_HOSTED__
+	abort();
+#elif __is_myos_kernel
+	panic("Stack smashing detected");
+#endif
+}