| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 42/52] userns: Allow setting gid_maps without privilege when setgroups is disabled | Date | Tue, 6 Jan 2015 18:07:10 -0800 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: "Eric W. Biederman" <ebiederm@xmission.com>
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 <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/user_namespace.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -818,6 +818,11 @@ static bool new_idmap_permitted(const st 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; } }
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