Date: Fri, 1 Oct 2010 14:31:12 -0700 From: Joel Becker <Joel.Becker@...cle.com> To: Eugene Teo <eugene@...hat.com> Cc: oss-security <oss-security@...ts.openwall.com>, stable@...nel.org Subject: Re: Small exposure in ocfs2 fast symlinks. On Thu, Sep 30, 2010 at 10:32:14PM +0800, Eugene Teo wrote: > On 09/30/2010 01:49 PM, Joel Becker wrote: > >On Wed, Sep 29, 2010 at 08:30:09PM -0700, Greg KH wrote: > >>On Wed, Sep 29, 2010 at 07:04:07PM -0700, Joel Becker wrote: > >>>Hey Everyone, > >>> We just discovered that ocfs2 could walk off the end of fast > >>>symlinks -- that is, symlinks that are stored directly in the inode > >>>block. ocfs2 terminates these with NUL characters, but a disk > >>>corruption or an attacker with direct access to the ocfs2 disk could > >>>overwrite the NUL. Following the symlink via the filesystem would walk > >>>off the end of the in-memory block buffer. We're not sure how > >>>exploitable this is, but I figured I'd provide a heads-up. The fix is > >>>in ocfs2's git tree and will be sent upstream tonight. Erratas with the > >>>fix are being built. > >> > >>Care to send the git commit id to the stable@...nel.org tree when it > >>hits Linus's tree so it gets backported there? > > > > I Cc'd stable@...nel.org in the commit, don't worry ;-) > > Thanks, please also cc oss-sec when the commit hash is available. The commit hash in Linus's tree is 1fc8a117865b54590acd773a55fbac9221b018f0. This problem only exists from 2.6.30 onwards; it is not present in older kernels. Joel -- "In the long run...we'll all be dead." -Unknown Joel Becker Consulting Software Developer Oracle E-mail: joel.becker@...cle.com Phone: (650) 506-8127
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