[lkml]   [2011]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [SECURITY] /proc/$pid/ leaks contents across setuid exec
    On Tue, Feb 08, 2011 at 02:43:15PM +1100, James Morris wrote:
    > On Mon, 7 Feb 2011, Kees Cook wrote:
    > > Sure, I know about O_CLOEXEC, but this is about protecting the
    > > just-been-execed setuid process from the attacking process that has no
    > > reason to set O_CLOEXEC.
    > >
    > > Something like this needs to be enforced on the kernel side. I.e. these
    > > file in /proc need to have O_CLOEXEC set in a way that cannot be unset.
    > >
    > > > Changing the behavior in the core kernel will break userspace.
    > >
    > > I don't think /proc/$pid/* needs to stay open across execs, does it? Or at
    > > least the non-0444 files should be handled separately.
    > Actually, this seems like a more general kind of bug in proc rather than a
    > leaked fd. Each child task should only see its own /proc/[pid] data.

    Right, that's precisely the problem. The unprivileged process can read
    the setuid process's /proc files.


    Kees Cook
    Ubuntu Security Team

     \ /
      Last update: 2011-02-08 05:29    [W:0.019 / U:36.592 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site