oss-sec mailing list archives
Re: kernel: tmpfs use-after-free
From: Kurt Seifried <kseifried () redhat com>
Date: Mon, 25 Feb 2013 14:26:09 -0700
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/25/2013 12:50 PM, Jason A. Donenfeld wrote:
Hey all, While everyone's going wild hndl->dump'ing with CVE-2013-1763, there's apparently been another silent security fix with 5f00110f7273f9ff04ac69a5f85bb535a4fd0987 [1]:tmpfs: fix use-after-free of mempolicy object The tmpfs remount logic preserves filesystem mempolicy if the mpol=M option is not specified in the remount request. A new policy can be specified if mpol=M is given. Before this patch remounting an mpol bound tmpfs without specifying mpol= mount option in the remount request would set the filesystem's mempolicy object to a freed mempolicy object. How far back does this issue go? I see it in both 2.6.36 and 3.3. I did not look back further.The commit message goes on with details on how to trigger it. Note that as of 5eaf563e53294d6696e651466697eb9d491f3946 [2], you can now mount filesystems as an unprivileged user after a call to unshare(CLONE_NEWUSER | CLONE_NEWNS), or a similar clone(2) call. This means all those random random filesystem bugs you have laying around in the junk bin are now quite useful. ++tricks; Cheers, Jason [1] http://git.zx2c4.com/linux/commit/?id=5f00110f7273f9ff04ac69a5f85bb535a4fd0987
[2] http://git.zx2c4.com/linux/commit/?id=5eaf563e53294d6696e651466697eb9d491f3946
-- Jason A. Donenfeld www.zx2c4.com
Please use CVE-2013-1767 for this issue. - -- Kurt Seifried Red Hat Security Response Team (SRT) PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) iQIcBAEBAgAGBQJRK9bxAAoJEBYNRVNeJnmT+KAP/2kWFMI53p1OVhS3/kIAySJl ScgB7KUoi7MbqG9yMlk2bN1/xsfea8fsZpGLRZKzHrzZ3b39EUKMSEH4hGqadlNm gYS4qcsSHK9h1ZXqtIboC8EtrJ/FabRw0rgD++LhqkoUhaDgjiwgHPBM4bd4E7TM Pq3Ch8aZawS4vB2CMHpXhFzpQv/r+S/PHl2ckfvrEOdhfLpEWyAF6e9FMJYI6H7+ UKOT8C39uFvHxtI2ktzdU+kvu8OdXq+xXYegcNld6oUQ3+8l1Nxscf49+SqqROM0 XaS272Rq4ABeMMTaPreRk+879vbUrDi2TbfbH863x5ZGQMMMHjTusSg/6/18kB4Q y6ZghNCNj9gzx2EmmS8GIt+JBVtYuQNiGZRVRdFW9McFgYS5eE9hydaa6SR/q7EI ZRteWVWfHsSt/ZFAL3EWbUQPNzEFg/M2z9q1Y2uDFYzWyzvIHYI+PWji45IO0bvw tq+k/3AqjZrSKPlO4rb8D4Mf7TMGgu6IDLye+6aBGklvZthW1qBXqS29dxctbhi7 w48Q8kUXCX72ha3EfHmDvek1OX/HBiKX3SRFH6TlvnRuyVUkoRssA0KyIxAuKqE0 71DUh9FACoHgiIsxsDruFVOLOo2EA8ZRkOhyPa7nZ3DcnJBU923pQY/FodIn7RI6 dein18BQzW+5i0yxZLXB =sB1j -----END PGP SIGNATURE-----
Current thread:
- kernel: tmpfs use-after-free Jason A. Donenfeld (Feb 25)
- Re: kernel: tmpfs use-after-free Kurt Seifried (Feb 25)
- Re: kernel: tmpfs use-after-free Solar Designer (Feb 25)