From: Andy Lutomirski Date: Sun, 14 Apr 2013 18:44:04 +0000 (-0700) Subject: userns: Changing any namespace id mappings should require privileges X-Git-Tag: v3.12-rc1~1037^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=41c21e351e79004dbb4efa4bc14a53a7e0af38c5;p=kernel%2Fkernel-generic.git userns: Changing any namespace id mappings should require privileges Changing uid/gid/projid mappings doesn't change your id within the namespace; it reconfigures the namespace. Unprivileged programs should *not* be able to write these files. (We're also checking the privileges on the wrong task.) Given the write-once nature of these files and the other security checks, this is likely impossible to usefully exploit. Signed-off-by: Andy Lutomirski --- diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 5c16f3a..e134d8f 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -613,10 +613,10 @@ static ssize_t map_write(struct file *file, const char __user *buf, if (map->nr_extents != 0) goto out; - /* Require the appropriate privilege CAP_SETUID or CAP_SETGID - * over the user namespace in order to set the id mapping. + /* + * Adjusting namespace settings requires capabilities on the target. */ - if (cap_valid(cap_setid) && !ns_capable(ns, cap_setid)) + if (cap_valid(cap_setid) && !file_ns_capable(file, ns, CAP_SYS_ADMIN)) goto out; /* Get a buffer */