Messages in this thread |  | | | From | Serge Hallyn <> | | Subject | user namespaces: fix some uid/privilege leaks | | Date | Tue, 18 Oct 2011 21:54:49 +0000 |
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The set of patches which I'm currently aiming to get upstream is queued at: http://kernel.ubuntu.com/git?p=serge/linux-2.6.git;a=shortlog;h=refs/heads/userns
In the below descriptions, it helps to remember that a task can have more privilege to his own, child, user namespace, than he does in his parent or the initial user namespace. In fact a task created in a new user namespace receives all capabilities (within bounding set) in the new user namespace. So checks for privilege in a task's own user ns can not be safely used in place of checks against another user ns.
The set includes:
0001-pid_ns-ensure-pid-is-not-freed-during-kill_pid_info_.patch Fix a case where a pid could be referenced after being freed. (This is in Greg's usb tree, but not yet in Linus' tree; it's here just to show full context)
0002-user-namespace-usb-make-usb-urbs-user-namespace-awar.patch Take the user namespace into account when comparing uids when signals are sent by usb urbs. (This is in Greg's usb tree, but not yet in Linus' tree; it's here just to show full context)
0003-user-namespace-make-signal.c-respect-user-namespaces.patch This convers the uid for the task sending a signal to the user namespace of the receiver. It is somewhat analogous to what is done with the sender's pid. Waiting on feedback from Oleg, but I believe this patch is ready.
0004-User-namespace-don-t-allow-sysctl-in-non-init-user-n.patch This prevents root in a child user namespace from man-handling sysctls. With this patch, a task in a child user namespace will only get the world access rights to sysctls.
0005-user-namespace-clamp-down-users-of-cap_raised.patch This clamps down on cases where privilege to your own user namespace were checked for access to the initial user namespace.
0006-Add-Documentation-namespaces-user_namespace.txt-v3.patch Documentation.
0007-user-namespace-make-each-net-net_ns-belong-to-a-user.patch This adds a struct user_namespace pointer to the net_ns for use by later patches.
0008-protect-cap_netlink_recv-from-user-namespaces.patch Now that net_ns is owned by a user_ns, cap_netlink_recv() can target privilege checks to the user_ns owning the resource. The current check against current_cap() is unsafe.
0009-make-net-core-scm.c-uid-comparisons-user-namespace-a.patch In scm_send, uids of sender/receiver are being compared without accounting for different user namespaces. Fix that.
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