README.md

@@ -73,4 +73,6 @@ PepperOS wouldn't be possible without the following freely-licensed software:
 - the [OSDev](https://osdev.org) wiki & forums
 - Intel 64 and IA-32 Architectures Software Developer's Manual
 - Documentation for the [GNU Compiler Collection](https://gcc.gnu.org/onlinedocs/gcc/)
-- dreamos82's [OSDev Notes](https://github.com/dreamportdev/Osdev-Notes/tree/master)
+- dreamos82's [OSDev Notes](https://github.com/dreamportdev/Osdev-Notes/tree/master)
+- the [Sortix UBsan hook implementations](https://gitlab.com/sortix/sortix/-/blob/main/libc/ubsan/ubsan.c)
+- the [CSC 395](https://curtsinger.cs.grinnell.edu/teaching/2022S/CSC395/kernel/) Kernel Development course from Grinnell College

include/boot/boot.h

@@ -0,0 +1,14 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Boot routines
+ * @license GPL-3.0-only
+ */
+
+#ifndef BOOT_H
+#define BOOT_H
+
+#include <kernel.h>
+
+void populate_boot_context(struct boot_context* boot_ctx);
+
+#endif

include/mem/gdt.h

@@ -1,6 +1,6 @@
 /*
  * @author  xamidev <xamidev@riseup.net>
- * @brief   Global Descriptor Table (for legacy reasons)
+ * @brief   Global Descriptor Table
  * @license GPL-3.0-only
  */
 

include/security/ubsan.h

@@ -56,4 +56,11 @@ struct ubsan_out_of_bounds_data
 	struct ubsan_type_descriptor* index_type;
 };
 
+struct ubsan_overflow_data
+{
+	struct ubsan_source_location location;
+	struct ubsan_type_descriptor* type;
+};
+
+
 #endif

src/boot/boot.c

@@ -9,7 +9,9 @@
  * @license GPL-3.0-only
  */
 
+#include <kernel.h>
 #include <limine.h>
+#include <stddef.h>
 
 __attribute__((used, section(".limine_requests")))
 volatile struct limine_framebuffer_request framebuffer_request = {
@@ -45,4 +47,15 @@ __attribute__((used, section(".limine_requests_start")))
 volatile LIMINE_REQUESTS_START_MARKER;
 
 __attribute__((used, section(".limine_requests_end")))
-volatile LIMINE_REQUESTS_END_MARKER;
+volatile LIMINE_REQUESTS_END_MARKER;
+
+void populate_boot_context(struct boot_context* ctx)
+{
+	// Populate boot context
+	// This stays valid only if the BOOTLOADER_RECLAIMABLE regions are preserved
+ 	ctx->fb = framebuffer_request.response ? framebuffer_request.response->framebuffers[0] : NULL;
+	ctx->mmap = memmap_request.response ? memmap_request.response : NULL;
+	ctx->hhdm = hhdm_request.response ? hhdm_request.response : NULL;
+	ctx->kaddr = kerneladdr_request.response ? kerneladdr_request.response : NULL;
+	ctx->bootdate = date_request.response ? date_request.response : NULL;
+}

src/kapps/kshell.c

@@ -44,6 +44,7 @@ void pedicel_main(void* arg)
             printf("\r\nYou are currently running the test kernel shell. This is not\r\n"
                         "a fully-fledged shell like you'd find in a complete operating system,\r\n"
                         "but rather a toy to play around in the meantime.\r\n\r\n"
+                            "clear   - clear the screen\r\n"
                             "panic   - trigger a test panic\r\n"
                             "syscall - trigger int 0x80\r\n"
                             "pf      - trigger a page fault\r\n"
@@ -52,6 +53,15 @@ void pedicel_main(void* arg)
             continue;
         }
 
+        if (strncmp(input_buf, "", 1) == 0) {
+            continue;
+        } 
+
+        if (strncmp(input_buf, "clear", 5) == 0) {
+            printf("\x1b[2J\x1b[H");
+            continue;
+        }
+
         if (strncmp(input_buf, "panic", 5) == 0) {
             panic(NULL, "test panic");
         }

src/kmain.c

@@ -4,8 +4,6 @@
  * @license GPL-3.0-only
  */
 
-#include "arch/x86.h"
-#include "time/date.h"
 #include <stdbool.h>	
 #include <stddef.h>
 #include <limine.h>
@@ -26,6 +24,7 @@
 #include <io/term/flanterm.h>
 #include <io/term/flanterm_backends/fb.h>
 #include <arch/x86.h>
+#include <boot/boot.h>
 
 // Limine version used
 __attribute__((used, section(".limine_requests")))
@@ -98,13 +97,7 @@ void kmain()
 	CLEAR_INTERRUPTS;
 	if (!LIMINE_BASE_REVISION_SUPPORTED) hcf();
 
-	// Populate boot context
-	// This stays valid only if the BOOTLOADER_RECLAIMABLE regions are preserved
- 	boot_ctx.fb = framebuffer_request.response ? framebuffer_request.response->framebuffers[0] : NULL;
-	boot_ctx.mmap = memmap_request.response ? memmap_request.response : NULL;
-	boot_ctx.hhdm = hhdm_request.response ? hhdm_request.response : NULL;
-	boot_ctx.kaddr = kerneladdr_request.response ? kerneladdr_request.response : NULL;
-	boot_ctx.bootdate = date_request.response ? date_request.response : NULL;
+	populate_boot_context(&boot_ctx);
 
 	term_init();
 	serial_init();

src/security/ubsan.c

@@ -158,3 +158,136 @@ void __ubsan_handle_out_of_bounds(void* data_raw, void* index_raw)
 
     panic(NULL, "Undefined Behavior Sanitization error: out of bounds");
 }
+
+/*
+ * __ubsan_handle_divrem_overflow - Hook for UBSan
+ * @data_raw:    pointer to error data
+ * @lhs_raw:     left hand side operator
+ * @rhs_raw:     right hand side operator
+ *
+ * This function is executed when the UBSan library detects
+ * following undefined behavior: division remainder overflow.
+ * It halts the system and gives the location of the code
+ * that triggered it.
+ */
+void __ubsan_handle_divrem_overflow(void* data_raw, void* lhs_raw, void* rhs_raw)
+{
+	struct ubsan_overflow_data* data = (struct ubsan_overflow_data*) data_raw;
+	uintptr_t lhs = (uintptr_t) lhs_raw;
+	uintptr_t rhs = (uintptr_t) rhs_raw;
+    struct ubsan_source_location* loc = &data->location;
+
+	DEBUG("\x1b[38;5;231mUBSan: division remainder overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+
+    if (init.all) {
+        printf("\x1b[38;5;231mUBSan: division remainder overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+    }
+
+    panic(NULL, "Undefined Behavior Sanitization error: division remainder overflow");
+}
+
+/*
+ * __ubsan_handle_sub_overflow - Hook for UBSan
+ * @data_raw:    pointer to error data
+ * @lhs_raw:     left hand side operator
+ * @rhs_raw:     right hand side operator
+ *
+ * This function is executed when the UBSan library detects
+ * following undefined behavior: subtraction overflow.
+ * It halts the system and gives the location of the code
+ * that triggered it.
+ */
+void __ubsan_handle_sub_overflow(void* data_raw, void* lhs_raw, void* rhs_raw)
+{
+	struct ubsan_overflow_data* data = (struct ubsan_overflow_data*) data_raw;
+	uintptr_t lhs = (uintptr_t) lhs_raw;
+	uintptr_t rhs = (uintptr_t) rhs_raw;
+	struct ubsan_source_location* loc = &data->location;
+
+	DEBUG("\x1b[38;5;231mUBSan: subtraction overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+
+    if (init.all) {
+        printf("\x1b[38;5;231mUBSan: subtraction overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+    }
+
+    panic(NULL, "Undefined Behavior Sanitization error: subtraction overflow");
+}
+
+/*
+ * __ubsan_handle_add_overflow - Hook for UBSan
+ * @data_raw:    pointer to error data
+ * @lhs_raw:     left hand side operator
+ * @rhs_raw:     right hand side operator
+ *
+ * This function is executed when the UBSan library detects
+ * following undefined behavior: addition overflow.
+ * It halts the system and gives the location of the code
+ * that triggered it.
+ */
+void __ubsan_handle_add_overflow(void* data_raw, void* lhs_raw, void* rhs_raw)
+{
+	struct ubsan_overflow_data* data = (struct ubsan_overflow_data*) data_raw;
+	uintptr_t lhs = (uintptr_t) lhs_raw;
+	uintptr_t rhs = (uintptr_t) rhs_raw;
+    struct ubsan_source_location* loc = &data->location;
+
+	DEBUG("\x1b[38;5;231mUBSan: addition overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+
+    if (init.all) {
+        printf("\x1b[38;5;231mUBSan: addition overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+    }
+
+    panic(NULL, "Undefined Behavior Sanitization error: addition overflow");
+}
+
+/*
+ * __ubsan_handle_mul_overflow - Hook for UBSan
+ * @data_raw:    pointer to error data
+ * @lhs_raw:     left hand side operator
+ * @rhs_raw:     right hand side operator
+ *
+ * This function is executed when the UBSan library detects
+ * following undefined behavior: multiplication overflow.
+ * It halts the system and gives the location of the code
+ * that triggered it.
+ */
+void __ubsan_handle_mul_overflow(void* data_raw, void* lhs_raw, void* rhs_raw)
+{
+	struct ubsan_overflow_data* data = (struct ubsan_overflow_data*) data_raw;
+	uintptr_t lhs = (uintptr_t) lhs_raw;
+	uintptr_t rhs = (uintptr_t) rhs_raw;
+	struct ubsan_source_location* loc = &data->location;
+
+	DEBUG("\x1b[38;5;231mUBSan: multiplication overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+
+    if (init.all) {
+        printf("\x1b[38;5;231mUBSan: multiplication overflow (lhs=%p, rhs=%p) at %s:%u:%u\x1b[0m", lhs, rhs, loc->filename, loc->line, loc->column);
+    }
+
+    panic(NULL, "Undefined Behavior Sanitization error: multiplication overflow");
+}
+
+/*
+ * __ubsan_handle_negate_overflow - Hook for UBSan
+ * @data_raw:      pointer to error data
+ * @old_value_raw: value before overflow
+ *
+ * This function is executed when the UBSan library detects
+ * following undefined behavior: negation overflow.
+ * It halts the system and gives the location of the code
+ * that triggered it.
+ */
+void __ubsan_handle_negate_overflow(void* data_raw, void* old_value_raw)
+{
+	struct ubsan_overflow_data* data = (struct ubsan_overflow_data*) data_raw;
+	uintptr_t old_value = (uintptr_t) old_value_raw;
+    struct ubsan_source_location* loc = &data->location;
+
+	DEBUG("\x1b[38;5;231mUBSan: negation overflow (old_value=%p) at %s:%u:%u\x1b[0m", old_value, loc->filename, loc->line, loc->column);
+
+    if (init.all) {
+        printf("\x1b[38;5;231mUBSan: negation overflow (old_value=%p) at %s:%u:%u\x1b[0m", old_value, loc->filename, loc->line, loc->column);
+    }
+
+    panic(NULL, "Undefined Behavior Sanitization error: negation overflow");
+}