From: Eric W. Biederman Date: Sat, 6 Dec 2014 01:36:04 +0000 (-0600) Subject: userns: Allow setting gid_maps without privilege when setgroups is disabled X-Git-Tag: firefly_0821_release~3679^2~1033 X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=afb5285388ce7e7623ab9ddb08f287551e70426f;p=firefly-linux-kernel-4.4.55.git userns: Allow setting gid_maps without privilege when setgroups is disabled commit 66d2f338ee4c449396b6f99f5e75cd18eb6df272 upstream. Now that setgroups can be disabled and not reenabled, setting gid_map without privielge can now be enabled when setgroups is disabled. This restores most of the functionality that was lost when unprivileged setting of gid_map was removed. Applications that use this functionality will need to check to see if they use setgroups or init_groups, and if they don't they can be fixed by simply disabling setgroups before writing to gid_map. Reviewed-by: Andy Lutomirski Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 9da8cbbcd985..3f2fb33d291a 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -814,6 +814,11 @@ static bool new_idmap_permitted(const struct file *file, kuid_t uid = make_kuid(ns->parent, id); if (uid_eq(uid, cred->euid)) return true; + } else if (cap_setid == CAP_SETGID) { + kgid_t gid = make_kgid(ns->parent, id); + if (!(ns->flags & USERNS_SETGROUPS_ALLOWED) && + gid_eq(gid, cred->egid)) + return true; } }