I was wondering what is a good permission set to put on the /usr/src directory? I can't do anything inside that directory now unless I am root. However, I want to be able to compile the kernel and when I do make menuconfig I don't have the permissions for it. Are there any suggestions for this problem?

its just a general directory, so i wouldn't be overly scared to set high permissions

like
777

that way everyone can use that directory, but id probably suggest maybe setting tighter permissions on certain files/folders in that directory that are important

When dealing with permissions, my "motto" per se is:
Use as strict a set of permissions as you can to perform your desired function.

So, I personally wouldn't set a 777 on just about anything on my system. Instead, in the case of kernel compiling in /usr/src I'd instead create me a "compile" or "kernel" group:
groupadd kernel
And then add my user to this group:
usermod -G kernel masterc
And then chown the directory to that group:
chown -R root.kernel /usr/src
And finally, ensure the chmod matched that for proper execution:
chmod 750 /usr/src
And then from that point on, whatever users I wanted to allow to compile a kernel I'd simply have to add them to the kernel group.

It may seem extensive and some may consider it a bit of overkill, especially for something in /usr/src however it's what I would consider the "proper" way as permissions are certainly something linux excels in that other OS don't.

Cool

Good suggestions guys, as always thanks for the help! I have went ahead and done as you suggested, creating a kernel compiling group. I actually already did that just wasn't sure about how to use the chown in the correct way.

Well, I have to agree with setting conservative permissions. Setting a system directory to 777 can be dangerous and should best be avoided. Also, Linus recommends strongly against compiling a kernel in /usr/src. I always compile a kernel in my /home directory, that way permissions are not an issue at all except to do make menu_config, and installing the actual kernel. There are other reasons for not compiling a kernel in /usr/src, but they don't come to mind at the moment. Check out www.kernel.org, or http://kerneltrap.org/ for more info.