Re: [CFT][PATCH 7/7] userns: Allow setting gid_maps without privilege when setgroups is disabled
From: Andy Lutomirski <hidden>
Date: 2014-12-08 22:27:10
Also in:
linux-man, lkml, stable
On Mon, Dec 8, 2014 at 2:14 PM, Eric W. Biederman [off-list ref] wrote:
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 unprivilege
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 of setgroups before they run.
"disabling setgroups before writing to gid_map"? The code is: Reviewed-by: Andy Lutomirski <redacted>
quoted hunk ↗ jump to hunk
Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Signed-off-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> --- kernel/user_namespace.c | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 3d128f91ced3..459c7f647072 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c@@ -828,6 +828,11 @@ 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 (!userns_setgroups_allowed(ns) && + gid_eq(gid, cred->egid)) + return true; } } --1.9.1
-- Andy Lutomirski AMA Capital Management, LLC