Thursday, February 7, 2002

Question:

I got my bomb, but it won't run! gdb keeps complaining about "Permission Denied".

Answer:

Your bomb probably got stripped of executable permissions in the process of getting it to your home directory. You should run the command

chmod +x <bomb filename>

to put the permissions back.

	Thursday, January 31, 2002

Question:

I downloaded a bomb to get started on L2. As it happens I don't know at this stage whether I will be working with a partner. If I am, can I merely email the course staff with this updated information and keep working on the same bomb?

Answer:

If you get a partner, you really need to download a new bomb for your group. Unfortunately, the problem is that if your partner joins you late, he/she won't have the benefit of doing the early stages that you did by yourself, or vice-versa. I'm concerned that someone would end up losing out -- and it is really a great project.

The new bomb may be easier for you if you've each started your own -- but at least you'll have the experience of working together on it through the several stages.

If you are having trouble finding a partner, you might try posting to the class bboard. I can also try to make an announcement after class on Tuesday and try to do some matchmaking, if you'd like.

Question:

I was wondering if lab 2 needed to be done on the fish machines? and if so, are the accounts ready? i cant seem to log in.

Answer:

Yes, the lab does need to be done on one of the fish machines. This was done to keep the coompetitive spirit of the project. Otherwise, they could be run on a machine without a network connection and the explosions would not be recorded.

Yes, the accounds have been created. If you are having trouble logging in, pleasde check to make sure you've followed the steps outlined within the "Fish" section of the course Web space. If you're still having trouble, please mail us again -- we're here to help.

Question:

Just before, I have got my bomb for assignment #2. My email reader does not show the bomb as an attachment, so I save the email and extract it. I extracted the file on andrew machine, and bombX folder, and I can see two files named "bomb" and "bomb.c". Did I do this right?? What kind of file is the "bomb" ?

Answer:

You decoded it the right way. It comes through uuencoded, instead of as a MIME attachment

The "bomb" file is a Linux/x86 executible. This si the bomb program that you want to defuse. Remember, your goal is to use a debugger, disassembler, &c to figure out enogh about its control flow to coax it to running to the end -- without exploading.