Re: [patch 2/2] ufd v1 - use unsequential O(1) fdmap

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Davide Libenzi wrote:
>> If randomizing each allocator is too expensive then randomize at the
>> very least the number of the first descriptor you give out.
> 
> Can you tell me how this can be a problem, and in which way making a 
> random thing would help?

In attacking an application every bit of known data can be used in an
exploit.  Be it something as simple as having a predetermined value at a
certain point in the program since it loaded a file descriptor into a
register.

But what I'm mostly thinking about is the case where I/O could be
redirected.  The intruding program could call dup2() and suddenly the
program wanting to write a password to disk could be directed to send it
over a socket.  One could imagine countless such attacks.

I don't say such an attack exists today.  But this is no reason to not
implement these extra security measures.  The cost of a randomized star
base (offset from 2^30) should be zero.

- --
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (GNU/Linux)

iD8DBQFGYyid2ijCOnn/RHQRAjRoAJ9XsAazZtc9V3AxaPjiNMjK8jPUZgCdG/Eg
KPug5Sq9REHd6H3AR0ax2aU=
=9iUM
-----END PGP SIGNATURE-----
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux