On Tue, Nov 17, 2015 at 05:05:56PM +0000, Al Viro wrote: > On Tue, Nov 17, 2015 at 10:39:03AM -0600, Seth Forshee wrote: > > Hi Eric, > > > > Here's another update to my patches for user namespace mounts, based on > > your for-testing branch. These patches add safeguards necessary to allow > > unprivileged mounts and update SELinux and Smack to safely handle > > device-backed mounts from unprivileged users. > > > > The v2 posting received very little in the way of feedback, so changes > > are minimal. I've made a trivial style change to the Smack changes at > > Casey's request, and I've added Stephen's ack for the SELinux changes. > > Would you mind explaining which filesystem types do you plan to allow? > SELinux and the rest of Linux S&M bunch do fuck-all for attacks via > handcrafted fs image fed to the code in fs driver that does not expect > a given kind of inconsistencies. > > As it is, validation of on-disk metadata is not particularly strong; > what's more, protection against concurrent malicious *changes* of > fs image (via direct writes by root) is simply inexistent. > > So what is that about? The first target is fuse, which won't be vulnerable to those attacks. Shortly after that I plan to follow with support for ext4. I've been fuzzing ext4 for a while now and it has held up well, and I'm currently working on hand-crafted attacks. Ted has commented privately (to others, not to me personally) that he will fix bugs for such attacks, though I haven't seen any public comments to that effect. Seth -- 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
