On Tue, Mar 6, 2012 at 5:12 PM, Andy Whitcroft <apw@xxxxxxxxxxxxx> wrote: > On Mon, Mar 05, 2012 at 06:18:23PM +0100, Miklos Szeredi wrote: >> Andy Whitcroft <apw@xxxxxxxxxxxxx> writes: >> >> > When checking permissions on an overlayfs inode we do not take into >> > account either device cgroup restrictions nor security permissions. >> > This allows a user to mount an overlayfs layer over a restricted device >> > directory and by pass those permissions to open otherwise restricted >> > files. >> > >> > Use devcgroup_inode_permission() and security_inode_permission() against >> > the underlying inodes when calculating ovl_permission(). >> >> Andy, >> >> Thanks for the patch. >> >> __devcgroup_inode_permission() and security_inode_permission() are not >> exported to modules, so this will not work if overlayfs is a module. >> >> We could export those but I think a better solution is to split out the >> part of inode_permission() that doesn't check for a read-only fs and >> export that. > > Yeah that makes much more sense. I got caught out by some exports > required for aufs3 which was also applied in my test environment. > > How about the following pair of patches? > > -apw > -- Hi, what is the status of this patch? Ubuntu has it included in precise kernel and it fixes a security issues as well. [1] says: CVE-2012-0055 BugLink: http://bugs.launchpad.net/bugs/915941 BugLink: http://bugs.launchpad.net/bugs/918212 What's up with the followup (splitted) patches which should replace this single one? My inbox says: [PATCH 1/2] inode_only_permission: export inode level permissions checks [PATCH 2/2] overlayfs: switch to use inode_only_permissions As I build OverlayFS as module those two new patches would be much appreciated. To quote Miklos: "__devcgroup_inode_permission() and security_inode_permission() are not exported to modules, so this will not work if overlayfs is a module." Thanks for any clarification in advance. - Sedat - [1] http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-precise.git;a=commit;h=59aa87f808b13463bc717ad69362b5372f6c5574 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
