Date: Tue, 4 Aug 1998 13:19:01 -0400
From: Zachary Amsden <amsdenz@AAVID.COM>
To: BUGTRAQ@netspace.org
Subject: linux kernel patch - suid procs exec'd with bad 0,1,2 fds
Patch for current linux kernels
If a priviledged process is exec'd by a user who closes
file descriptors on it, many poorly written programs do
not notice and libc printf functions may have access to
any files opened. This can be used to crash the system
by corrupting memory or in some cases, compromise root.
This doesn't attempt to fix the fds for such a process,
that would be not quite right in a chrooted environment
with no /dev/null, and creating fake dentries and inode
is too much work for something that is not quite useful
Instead, we just fall through the standard error checks
and return EPERM
This doesn't break pipelines or any other traditional
UNIX functionality that I am aware of.
Zachary Amsden
amsden@andrew.cmu.edu
begin 666 suidbadfd.txt
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!"@``
`
end
