[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-26 Thread Launchpad Bug Tracker
This bug was fixed in the package linux - 4.4.0-8.23 --- linux (4.4.0-8.23) xenial; urgency=low * cgroup namespace mounts broken in containers (LP: #1549398) - SAUCE: kernfs: Always set super block owner to init_user_ns * 4.4.0-7.22 no longer boots on arm64 (LP: #1547718)

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-24 Thread Launchpad Bug Tracker
** Branch linked: lp:~ubuntu-branches/ubuntu/trusty/linux-lts-wily /trusty-security ** Branch linked: lp:~ubuntu-branches/ubuntu/trusty/linux-lts-wily /trusty-proposed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-24 Thread Launchpad Bug Tracker
** Branch linked: lp:ubuntu/trusty-security/linux-lts-vivid ** Branch linked: lp:ubuntu/trusty-proposed/linux-lts-vivid -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1531747 Title: ove

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-24 Thread Alberto Salvia Novella
** Changed in: linux-lts-wily (Ubuntu Wily) Importance: Undecided => High ** Changed in: linux-lts-wily (Ubuntu Xenial) Importance: Undecided => High -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.laun

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-23 Thread Launchpad Bug Tracker
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: linux-lts-wily (Ubuntu Wily) Status: New => Confirmed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-23 Thread Launchpad Bug Tracker
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: linux-lts-wily (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-22 Thread Launchpad Bug Tracker
This bug was fixed in the package linux - 4.2.0-30.35 --- linux (4.2.0-30.35) wily; urgency=low [ Seth Forshee ] * SAUCE: cred: Add clone_cred() interface - LP: #1531747, #1534961, #1535150 - CVE-2016-1575 CVE-2016-1576 * SAUCE: overlayfs: Use mounter's credentials inst

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-15 Thread Philipp Wendler
** Also affects: linux-lts-wily (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1531747 Title: overlay: mkdir fails if directory exist

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-02-02 Thread Seth Forshee
** Changed in: linux (Ubuntu Wily) Assignee: (unassigned) => Seth Forshee (sforshee) ** Changed in: linux (Ubuntu Xenial) Assignee: (unassigned) => Seth Forshee (sforshee) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-19 Thread Joseph Salisbury
** Tags removed: kernel-key ** Tags added: kernel-da-key -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1531747 Title: overlay: mkdir fails if directory exists in lowerdir in a user na

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-17 Thread oleg
FWIW, bug #1480411, "rm -r * fails to delete directories when using overlayfs in a user-namespace", might be a duplicate of this bug. In both bugs the script works on the host but fails in a user-namespace with error EPERM. In this bug the operation which triggers the error is 'mkdir', while in

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-14 Thread Seth Forshee
ovl_rename2 seems okay. As before, the vfs does inode permission checks on the overlayfs inodes which results in checks on the upper and/or lower dir inodes as appropriate. These checks appear to be sufficient to imply permission to do everything ovl_rename2 does with elevated credentials. That sai

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-14 Thread Serge Hallyn
> Something I'm still not sure about is what would happen if you made a > symlink, bind mount, etc. in upperdir with the same name as an unrelated > file in lowerdir. This is worth checking out. just tried a symlink and it didn't seem to affect the host directory (/opt/cisco) which was symlinked t

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-14 Thread Seth Forshee
On Thu, Jan 14, 2016 at 12:17:06AM -, Serge Hallyn wrote: > Does it require the workdir to be empty? Not empty. It wants to remove workdir/work if it exists and then create workdir/work, see ovl_workdir_create. Removing workdir/work is done as the user which is mounting, so nothing can be remo

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-13 Thread Serge Hallyn
Does it require the workdir to be empty? I.e. is there a way (symlink, bind mount, something else) that a user could use a dir they own which has a child which they don't own? It looks like no, since root@w1:/tmp# mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=workdir overlay /mnt ro

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-13 Thread Seth Forshee
On Tue, Jan 12, 2016 at 05:16:28PM -, Serge Hallyn wrote: > I'm still looking, but it may be safe to say that all needed inode > checks are already done before we call ovl_set_opaque() so that we > can indeed just use prepare_kernel_cred(NULL) instead of prepare_cred(). I've been looking too,

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-12 Thread Seth Forshee
On Tue, Jan 12, 2016 at 05:16:28PM -, Serge Hallyn wrote: > in ovl_clear_empty(), the opaque bit is set on the dir in workingdir > > in ovl_create_over_whiteout() (the case we're currently looking at) it is > also being set in the working dir. > > in ovl_rename2(), it is set in two places, on

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-12 Thread Seth Forshee
On Tue, Jan 12, 2016 at 04:56:24PM -, Serge Hallyn wrote: > Quoting Seth Forshee (seth.forshee...@canonical.com): > > I don't know why #2 is that much grosser than what's there now. It's > > I didn't mean gross as in eeuw, I meant not fine-grained enough. > > Because the capability will apply

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-12 Thread Serge Hallyn
in ovl_clear_empty(), the opaque bit is set on the dir in workingdir in ovl_create_over_whiteout() (the case we're currently looking at) it is also being set in the working dir. in ovl_rename2(), it is set in two places, on the upper dentries for both the old and new. So it is never set on the l

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-12 Thread Serge Hallyn
Quoting Seth Forshee (seth.forshee...@canonical.com): > I don't know why #2 is that much grosser than what's there now. It's I didn't mean gross as in eeuw, I meant not fine-grained enough. Because the capability will apply to inode permissions checks, and we only want it to be used for the check

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-12 Thread Seth Forshee
I don't know why #2 is that much grosser than what's there now. It's already only taking the cap for setting the xattr, and taking CAP_SYS_ADMIN in init_user_ns seems to be what it's really wanting to do there. The difference now though is that before that capability would have been required to do

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-11 Thread Serge Hallyn
hat may not be ok for the ovl_rename2 case. What we want is for inode permissions to be checked, but only the bit in xattr_permission() checking for trusted.* to accept ns_capable. We could special-case that in xattr_permission(), but that's not particularly nice. -- You received this bug notif

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-11 Thread Serge Hallyn
#2 is probably a bit too gross - we really only need the cap for the setting of the OVL_XATTR_OPAQUE xattr in ovl_set_opaque. So we could simply override creds again there. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu.

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-11 Thread Seth Forshee
Hmm. In this case it's really the kernel that is writing the xattr, so in that case #2 kind of makes sense. It's also more than a bit scary, assigning CAP_SYS_ADMIN in init_user_ns to a task from a user namespace. Now we're already doing it for unprivileged users in init_user_ns which isn't all tha

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-08 Thread Serge Hallyn
Ok, I see. At one point we had a special case to allow the overlay code to write trusted.* xattrs for creating whiteouts. However that is gone. Therefore when overlayfs v1 (mount -t overlayfs) is mounted, root in a user namespace also is not able to rm a file which exists in the lower fs. Some

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-08 Thread Serge Hallyn
The type of the underlaying file does not matter, only the type of the replacing object. So if you touch $t/dev; rm $t/dev; touch $t/dev mkdir $t/dev; rmdir $t/ev; touch $t/dev those succeed, while touch $t/dev; rm $t/dev; mkdir $t/dev mkdir $t/dev; rm $t/dev; mkdir $t/dev both fail. -- You

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-08 Thread Serge Hallyn
In ovl_create_over_whiteout(), the ovl_set_opaque() in the S_ISDIR() block failed. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1531747 Title: overlay: mkdir fails if directory exists

Re: [Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-07 Thread Serge Hallyn
Quoting Joseph Salisbury (joseph.salisb...@canonical.com): > Can you see if this bug also happens with the latest mainline kernel? It can > be downloaded from: That is not an option, because the mainline kernel doesn't support unprivileged overlayfs mounting which is where this happens. -- You

[Kernel-packages] [Bug 1531747] Re: overlay: mkdir fails if directory exists in lowerdir in a user namespace

2016-01-07 Thread Joseph Salisbury
Can you see if this bug also happens with the latest mainline kernel? It can be downloaded from: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4-rc8-wily ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Tags added: kernel-key wily xenial ** Changed in: linux (Ubuntu) I