From be7c6dba2332cef0677fbabb606e279ae76652c3 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 5 Dec 2014 18:14:19 -0600 Subject: [PATCH] userns: Don't allow unprivileged creation of gid mappings 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. Cc: stable@vger.kernel.org Reviewed-by: Andy Lutomirski Signed-off-by: "Eric W. Biederman" --- Reading git-format-patch failed