cifs: make cifs_copy_sid handle a source sid with variable size subauth arrays

...and lift the restriction in id_to_sid upcall that the size must be
at least as big as a full cifs_sid.

Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 5a312eb45a92..141a944c9dfd 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -277,8 +277,14 @@ compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid)
 static void
 cifs_copy_sid(struct cifs_sid *dst, const struct cifs_sid *src)
 {
-        memcpy(dst, src, sizeof(*dst));
+        int i;
+
+        dst->revision = src->revision;
         dst->num_subauth = min_t(u8, src->num_subauth, NUM_SUBAUTHS);
+        for (i = 0; i < NUM_AUTHS; ++i)
+                dst->authority[i] = src->authority[i];
+        for (i = 0; i < dst->num_subauth; ++i)
+                dst->sub_auth[i] = src->sub_auth[i];
 }
 
 static void
@@ -427,7 +433,7 @@ id_to_sid(unsigned long cid, uint sidtype, struct cifs_sid *ssid)
                 if (IS_ERR(sidkey)) {
                         rc = -EINVAL;
                         cFYI(1, "%s: Can't map and id to a SID", __func__);
-                } else if (sidkey->datalen < sizeof(struct cifs_sid)) {
+                } else if (sidkey->datalen < CIFS_SID_BASE_SIZE) {
                         rc = -EIO;
                         cFYI(1, "%s: Downcall contained malformed key "
                                 "(datalen=%hu)", __func__, sidkey->datalen);