Messages in this thread Patch in this message | | | From | (Eric W. Biederman) | Date | Tue, 09 Dec 2014 14:43:17 -0600 | Subject | [CFT][PATCH 8/8] userns: Allow setting gid_maps without privilege when setgroups is disabled |
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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.
Cc: stable@vger.kernel.org Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> --- kernel/user_namespace.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index b507f9af7ff2..3b29b9a52332 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -826,6 +826,11 @@ 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; } } -- 1.9.1
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