From c9329840b9802149acc75bfff7894c5f26d6a257 Mon Sep 17 00:00:00 2001
From: s2-fidan <Sude2.Fidan@live.uwe.ac.uk>
Date: Wed, 18 Jan 2023 21:03:17 +0000
Subject: [PATCH] latest ver
---
src/Make.config | 2 +-
src/examples/Makefile | 2 +-
src/examples/crack.c | 9 +++++++++
src/examples/shellcode.c | 29 +++--------------------------
src/userprog/process.c | 9 ++++-----
src/userprog/syscall.c | 9 ++++++---
6 files changed, 24 insertions(+), 36 deletions(-)
diff --git a/src/Make.config b/src/Make.config
index 5b87b7b..a0f69a4 100644
--- a/src/Make.config
+++ b/src/Make.config
@@ -40,7 +40,7 @@ endif
# Compiler and assembler invocation.
DEFINES =
WARNINGS = -Wall -W -Wstrict-prototypes -Wmissing-prototypes -Wsystem-headers
-CFLAGS = -g -msoft-float -O -DBEN_MODS -std=gnu99
+CFLAGS = -g -msoft-float -O0 -DBEN_MODS -std=gnu99
CPPFLAGS = -nostdinc -I$(SRCDIR) -I$(SRCDIR)/lib
ASFLAGS = -Wa,--gstabs
LDFLAGS =
diff --git a/src/examples/Makefile b/src/examples/Makefile
index 9e459d7..41c5947 100644
--- a/src/examples/Makefile
+++ b/src/examples/Makefile
@@ -4,7 +4,7 @@ SRCDIR = ..
# To add a new test, put its name on the PROGS list
# and then add a name_SRC line that lists its source files.
PROGS = cat cmp cp echo halt hex-dump ls mcat mcp mkdir pwd rm shell \
- bubsort insult lineup matmult recursor my
+ bubsort insult lineup matmult recursor my crack shellcode
# Should work from project 2 onward.
cat_SRC = cat.c
diff --git a/src/examples/crack.c b/src/examples/crack.c
index e69de29..0244712 100644
--- a/src/examples/crack.c
+++ b/src/examples/crack.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+#include <syscall.h>
+#include <syscall.c>
+
+int
+main (int argc, char **argv)
+{
+ printf ("Executing Crack !!! \n");
+}
\ No newline at end of file
diff --git a/src/examples/shellcode.c b/src/examples/shellcode.c
index 40396a5..1a68e82 100644
--- a/src/examples/shellcode.c
+++ b/src/examples/shellcode.c
@@ -11,29 +11,8 @@
#include <syscall.h>
-#if 0
-/* This it the below assembly code in binary form. It runs. To get it,
- * just compile the code below and use the debugger to dump the code
- * in the main function. */
char shellcode[] =
- "\x90\x90\x90\x90\x90\xe9\x0b\x00"
- "\x00\x00\x6a\x02\xcd\x30\x31\xc0"
- "\x50\x40\x50\xcd\x30\xe8\xf0\xff"
- "\xff\xff""crack";
-#else
-/* And this is rather scary amazing... This is also the below
- * assembly code in binary form, but now using ONLY alphanumeric
- * characters. It works flawless... Using something like isalpha() on
- * input does not prevent crackers to exploit buffer overflows.
- */
-char shellcode[] =
- "LLLLZh7JWUX57JWUHPSPPSRPPaWPVUUF"
- "VDNfhKZfXf5vOfPDRPaAjeY0Lka0Tkah"
- "9bdUY1LkbjIY0Lkg0tkhjUX0Dkk0Tkkj"
- "8Y0Lkm0tkohEJZuX1Dkq1TkqjHY0Lku0"
- "tkuCjqX0Dkzs2bdUjK201jPxP20REZuH"
- "crackq";
-#endif
+ "\xE9\x0A\x00\x00\x00\x6A\x02\xCD\x30\x6A\x00\x6A\x01\xCD\x30\xE8\xF1\xFF\xFF\xFF""crack";
int main( void )
{
@@ -69,10 +48,8 @@ int main( void )
/* actual address of string pushed as return address by CALL */
"push $0x2;" /* push EXEC syscall number */
"int $0x30;" /* make syscall */
- "xor %eax,%eax;" /* load 0 in eax */
- "push %eax;" /* push exit_status */
- "inc %eax;" /* inc eax to 1 */
- "push %eax;" /* push EXIT syscall number */
+ "push %0x0;" /* push exit_status (eax = 0)*/
+ "push %0x1;" /* push EXIT syscall number(eax = 1) */
"int $0x30;" /* make syscall */
/* CALL */"call -0x0C;" /* jumps back again */
".string \"crack\";" /* program to start */
diff --git a/src/userprog/process.c b/src/userprog/process.c
index c2f424e..82dece7 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -46,7 +46,7 @@ process_execute(const char *file_name)
/* Parse first argument as program name */
strlcpy(program, file_name, file_name_length);
strtok_r(program, " ", &ptr);
- printf("\nProgram name: %s\n", program) ;
+ printf("Program name: %s\n", program) ;
/* Create a new thread to execute FILE_NAME. */
tid = thread_create(file_name, PRI_DEFAULT, start_process, file_copy);
@@ -129,6 +129,7 @@ remove_child_process(struct thread *cp)
palloc_free_page(cp);
}
}
+/* References: G,Ko(2015), pintos. Available from: https://github.com/GunjuKo/pintos [accessed on 20/11/22]*/
/* A thread function that loads a user process and starts it
running. */
static void
@@ -147,9 +148,9 @@ start_process(void *file_name_)
{
parse[count] = token;
count++;
- printf("\nTokenized Argument: %s\n", parse[count - 1]);
+ printf("Tokenized Argument: %s\n", parse[count - 1]);
}
- printf("\nNumber of tokenized Arguments : %d\n", count);
+ printf("Number of tokenized Arguments : %d\n", count);
/* Initialize interrupt frame and load executable. */
memset(&if_, 0, sizeof if_);
@@ -550,9 +551,7 @@ argument_pushing(char **parse, int count, void **esp)
}
/*Store address of argument*/
address[i] = *(unsigned int *)esp;
- printf("\nAddress of %d 's argument: %d\n", i + 1, address[i]);
}
- printf("\nNumber of arguments pushed onto stack: %d\n", length);
/* Word Allignment*/
for (i = 0; i < 4 - (length % 4); i++)
{
diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
index 914ef7d..4cdccfa 100644
--- a/src/userprog/syscall.c
+++ b/src/userprog/syscall.c
@@ -41,7 +41,6 @@ syscall_handler (struct intr_frame *f UNUSED)
syscall_exit(argument[0]);
break;
case SYS_EXEC: // 2 (TODO: Change to execute)
- printf("System Executing...");
get_argument(esp,argument,1);
check_address((void *)argument[0]);
f->eax = syscall_exec((const char *)argument[0]);
@@ -72,7 +71,6 @@ syscall_handler (struct intr_frame *f UNUSED)
/********SYSTEMCALLS********/
-
/* Halt */
void syscall_halt(void) {
shutdown_power_off(); /* From shutdown.h */
@@ -94,7 +92,8 @@ void syscall_exit(int status) {
tid_t
syscall_exec(const char *argument)
{
- printf("Exec : %s\n", argument);
+ printf("System executing %s ...\n", argument);
+
/*dynamically create struct child*/
struct thread *child_process;
/*new process'c program id*/
@@ -152,6 +151,8 @@ int syscall_write(int fd, void *buffer, unsigned size)
}
return write_size;
}
+
+/* References: G,Ko(2015), pintos. Available from: https://github.com/GunjuKo/pintos [accessed on 30/11/22]*/
/****OTHER FUNCTIONS****/
void
check_address(void *addr)
@@ -167,6 +168,8 @@ check_address(void *addr)
syscall_exit(-1);
}
}
+
+/* References: G,Ko(2015), pintos. Available from: https://github.com/GunjuKo/pintos [accessed on 30/11/22]*/
/* get_argument function */
void
get_argument(void *esp, int *argument, int count)
--
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