knfsd: Validate filehandle type in fsid_source

patch b8da0d1c27f144bce999c653467106f3f0d5a308 in mainline.

fsid_source decided where to get the 'fsid' number to
return for a GETATTR based on the type of filehandle.
It can be from the device, from the fsid, or from the
UUID.

It is possible for the filehandle to be inconsistent
with the export information, so make sure the export information
actually has the info implied by the value returned by
fsid_source.

Signed-off-by: Neil Brown <neilb@suse.de>
Cc: "Luiz Fernando N. Capitulino" <lcapitulino@gmail.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oliver Pintr <oliver.pntr@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 6ca2d24fc216d6cf5ccf6f293955b0ad27accb73..f83d235573aec904f46b011f1f6229acc88bd466 100644 (file)
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -565,13 +565,23 @@ enum fsid_source fsid_source(struct svc_fh *fhp)
        case FSID_DEV:
        case FSID_ENCODE_DEV:
        case FSID_MAJOR_MINOR:
-               return FSIDSOURCE_DEV;
+               if (fhp->fh_export->ex_dentry->d_inode->i_sb->s_type->fs_flags
+                   & FS_REQUIRES_DEV)
+                       return FSIDSOURCE_DEV;
+               break;
        case FSID_NUM:
-               return FSIDSOURCE_FSID;
-       default:
                if (fhp->fh_export->ex_flags & NFSEXP_FSID)
                        return FSIDSOURCE_FSID;
-               else
-                       return FSIDSOURCE_UUID;
+               break;
+       default:
+               break;
        }
+       /* either a UUID type filehandle, or the filehandle doesn't
+        * match the export.
+        */
+       if (fhp->fh_export->ex_flags & NFSEXP_FSID)
+               return FSIDSOURCE_FSID;
+       if (fhp->fh_export->ex_uuid)
+               return FSIDSOURCE_UUID;
+       return FSIDSOURCE_DEV;
 }