On Jan 4, 2011, at 3:57 PM, J. Bruce Fields wrote: > On Tue, Jan 04, 2011 at 03:42:34PM -0500, andros@xxxxxxxxxx wrote: >> >> >> Version 7 of these patches >> Applies to Tronds nfs-for-next branch >> >> Already acked by bfields >> ------------------------ >> 0001-SUNRPC-move-svc_drop-to-caller-of-svc_process_common.patch >> 0002-SUNRPC-fix-bc_send-print.patch >> 0010-NFS-RPC_AUTH_GSS-unsupported-on-v4.1-back-channel.patch >> 0012-NFS-rename-client-back-channel-transport-field.patch > > In future, if you don't mind actually adding the "Acked-by"'s to those > patches with your signed-off-by's, that'll help remind me which ones > I've read before as I'm looking through them.... > > (Well, unless you've changed them in some non-trivial way and want me to > reread them.) Sure. -->Andy > > --b. > >> >> Responded to Version 6 comments from bfields. >> --------------------------------------------- >> 0003-SUNRPC-new-transport-for-the-NFSv4.1-shared-back-cha.patch >> 0004-NFS-register-and-unregister-back-channel-transport.patch >> >> Unchanged: >> ---------- >> 0005-NFS-use-svc_create_xprt-for-NFSv4.1-callback-service.patch >> 0006-NFS-do-not-clear-minor-version-at-nfs_client-free.patch >> 0007-NFS-implement-v4.0-callback_ident.patch >> 0008-NFS-associate-sessionid-with-callback-connection.patch >> 0009-NFS-refactor-nfs_find_client-and-reference-client-ac.patch >> 0011-NFS-add-session-back-channel-draining.patch >> >> >> 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. >> >> -->Andy >> >> -- >> 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 > -- > 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 -- 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
