From: Christian Brauner <christian.brauner@xxxxxxxxxx>
The sid_to_id() functions is relevant when changing ownership of
filesystem objects based on acl information. In this case we need to
first translate the relevant s*ids into k*ids in ksmbd's user namespace
and account for any idmapped mounts. Requesting a change in ownership
requires the inverse translation to be applied when we would report
ownership to userspace. So k*id_from_mnt() must be used here.
Cc: Steve French <stfrench@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Cc: Hyunchul Lee <hyc.lee@xxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: linux-cifs@xxxxxxxxxxxxxxx
Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
---
fs/ksmbd/smbacl.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c
index 0d269b28f163..ef5896297607 100644
--- a/fs/ksmbd/smbacl.c
+++ b/fs/ksmbd/smbacl.c
@@ -275,8 +275,15 @@ static int sid_to_id(struct user_namespace *user_ns,
id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]);
if (id >= 0) {
- uid = make_kuid(user_ns, id);
- if (uid_valid(uid) && kuid_has_mapping(user_ns, uid)) {
+ /*
+ * Translate raw sid into kuid in the server's user
+ * namespace.
+ */
+ uid = make_kuid(&init_user_ns, id);
+
+ /* If this is an idmapped mount, apply the idmapping. */
+ uid = kuid_from_mnt(user_ns, uid);
+ if (uid_valid(uid)) {
fattr->cf_uid = uid;
rc = 0;
}
@@ -286,9 +293,16 @@ static int sid_to_id(struct user_namespace *user_ns,
gid_t id;
id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]);
- gid = make_kgid(user_ns, id);
- if (gid_valid(gid) && kgid_has_mapping(user_ns, gid)) {
if (id >= 0) {
+ /*
+ * Translate raw sid into kgid in the server's user
+ * namespace.
+ */
+ gid = make_kgid(&init_user_ns, id);
+
+ /* If this is an idmapped mount, apply the idmapping. */
+ gid = kgid_from_mnt(user_ns, gid);
+ if (gid_valid(gid)) {
fattr->cf_gid = gid;
rc = 0;
}
--
2.30.2
