Version 8 of these patches Applies to Tronds nfs-for-next branch New for Version 8: - moved the reg/unregistration of the back channel transport to the RPC layer. - Use the small id to pointer translator service to provide a unique callback identifier. -->Andy The back channel server svc_process_common RPC layer pg_authenticate call [nfs_callback_authenticate] is shared by both the NFSv4.0 and the NFSv4.1 callback threads. It authenticates the incoming request by finding (and referencing) an nfs_client struct based on the incoming request address and the NFS version (4). This is akin to the NFS server which authenticates requests by matching the server address to the exports file client list. Since there is no minorversion in the search, it may find the wrong nfs_client struct. For the nfsv4.0 callback service thread, this means it could find an NFSv4.1 nfs_client. For the NFSv4.1 callback service thread, it could find an NFSv4.0 instead of v4.1, or find an NFSv4.1 nfs_client with the wrong session. The nfs_client is dereferenced at the end of pg_authenticate. Another nfs_find_client call is done in the NFS layouer per operation dispatcher routines for NFSv4.0 and in the cb_sequence operation dispatcher routine for NFSv4.1 after decoding. This means the callback server could start processing a callback, passing the pg_authenticate test, and have the nfs_client struct freed between the pg_authenticate call and the dispatcher operation call. Or, it could have found the wrong nfs_client in the pg_authenticate call. The current code has this behavior: If the nfs_client is not found in pg_authenticate, the request is simply dropped (SVC_DROP). If an nfs_client is not found in the dispatcher routines NFS4ERR_BADSESSION is returned for v4.1 requests and NFS4ERR_BADHANDLE for v4.0 requests. The fix is to implement the v4.0 SETCLIENTID callback_ident and use it to find the one and only client for v4.0 callbacks, and to associate the sessionid with the sessions based callback service (v4.1) and use it to identify the one and only client. This can be done in the NFS layer, in CB_COMPOUND header processing for v4.0 and in CB_SEQUENCE processing in v4.1. In both cases, a reference to the found client is held across CB_COMPOUND processing. The pg_authenticate method does not have the callback_ident for CB_NULL or CB_COMPOUND v4.0 processing, so just the server address, nfsversion and minorversion is used for the client search For sessions based callback service, the sessionID can't be set until the return of the CREATE_SESSION call, yet the CB_NULL ping from a server can be initiated by the server at the receipt of the CREATE_SESSION call before the response is sent. So for CB_NULL, the sessionid is (usually) not set, and the sessionid is not used for CB_NULL pg_authenticate client searches. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
