This is a note to let you know that I've just added the patch titled userns: Don't allow unprivileged creation of gid mappings to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: userns-don-t-allow-unprivileged-creation-of-gid-mappings.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From be7c6dba2332cef0677fbabb606e279ae76652c3 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Date: Fri, 5 Dec 2014 18:14:19 -0600 Subject: userns: Don't allow unprivileged creation of gid mappings From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> commit be7c6dba2332cef0677fbabb606e279ae76652c3 upstream. As any gid mapping will allow and must allow for backwards compatibility dropping groups don't allow any gid mappings to be established without CAP_SETGID in the parent user namespace. For a small class of applications this change breaks userspace and removes useful functionality. This small class of applications includes tools/testing/selftests/mount/unprivilged-remount-test.c Most of the removed functionality will be added back with the addition of a one way knob to disable setgroups. Once setgroups is disabled setting the gid_map becomes as safe as setting the uid_map. For more common applications that set the uid_map and the gid_map with privilege this change will have no affect. This is part of a fix for CVE-2014-8989. Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/user_namespace.c | 5 ----- 1 file changed, 5 deletions(-) --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -814,11 +814,6 @@ static bool new_idmap_permitted(const st if (uid_eq(uid, file->f_cred->fsuid)) return true; } - else if (cap_setid == CAP_SETGID) { - kgid_t gid = make_kgid(ns->parent, id); - if (gid_eq(gid, file->f_cred->fsgid)) - return true; - } } /* Allow anyone to set a mapping that doesn't require privilege */ Patches currently in stable-queue which might be from ebiederm@xxxxxxxxxxxx are queue-3.14/mnt-update-unprivileged-remount-test.patch queue-3.14/mnt-fix-a-memory-stomp-in-umount.patch queue-3.14/userns-check-euid-no-fsuid-when-establishing-an-unprivileged-uid-mapping.patch queue-3.14/mnt-implicitly-add-mnt_nodev-on-remount-when-it-was-implicitly-added-by-mount.patch queue-3.14/userns-don-t-allow-unprivileged-creation-of-gid-mappings.patch queue-3.14/userns-rename-id_map_mutex-to-userns_state_mutex.patch queue-3.14/userns-add-a-knob-to-disable-setgroups-on-a-per-user-namespace-basis.patch queue-3.14/userns-allow-setting-gid_maps-without-privilege-when-setgroups-is-disabled.patch queue-3.14/userns-don-t-allow-setgroups-until-a-gid-mapping-has-been-setablished.patch queue-3.14/groups-consolidate-the-setgroups-permission-checks.patch queue-3.14/userns-only-allow-the-creator-of-the-userns-unprivileged-mappings.patch queue-3.14/userns-document-what-the-invariant-required-for-safe-unprivileged-mappings.patch queue-3.14/umount-disallow-unprivileged-mount-force.patch queue-3.14/userns-unbreak-the-unprivileged-remount-tests.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html