Is vim bypassing all security or am I missing something?!?

ecosta · Guru Joined: 09 May 2003 Posts: 477 Location: Brussels,BE

I was plag with ACLs when I came onto a problem with permissions. I thought I misunderstood acls until I got the problem with standard unix permissions.

I created 2 users to demonstrate this and no ACLs have been set in these dirs although the filesystem was monted to use ACLs

/dev/sda3 / ext3 noatime,acl 0 1

Here is what I did to demonstrate what seems like vim not respecting linux permissions

vim version:

user: test01

timeBandit · Posted: Tue Mar 04, 2008 2:22 pm Post subject:

It's behaving as expected. Vim does not write to a file in place--it saves a new copy and removes the old one. This requires write access to the directory, not the file. You gave everyone write access to the directory (chmod 777) so vim was able to do this. Notice the apparent change in file ownership, because it's actually a new file with the same name.

However since the file itself is not world-writable, other users cannot modify it in place, as you saw with date > file.

Also, note that neither vim nor any user application "respects" the permission model--it's enforced by the kernel.
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ecosta · Guru Joined: 09 May 2003 Posts: 477 Location: Brussels,BE

Many thanks for the info. I never realised this... you learn something every day!

I didn't think there was a way for a user to overwrite another users perms if the settings where 600 but I am wizer now...

Thanks
-Ed
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