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Commit 1b74c25b authored by Mi Jinlong's avatar Mi Jinlong Committed by J. Bruce Fields
Browse files

nfsd41: error out when client sets maxreq_sz or maxresp_sz too small 



According to RFC5661, 18.36.3,

 "if the client selects a value for ca_maxresponsesize such that
  a replier on a channel could never send a response,the server
  SHOULD return NFS4ERR_TOOSMALL in the CREATE_SESSION reply."

So, error out when the client sets a maxreq_sz less than the minimum
possible SEQUENCE request size, or sets a maxresp_sz less than the
minimum possible SEQUENCE reply size.

Signed-off-by: default avatarMi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent f197c271

fs/nfsd/nfs4state.c

+27 −0
Original line number Diff line number Diff line
@@ -1506,6 +1506,29 @@ nfsd4_replay_create_session(struct nfsd4_create_session *cr_ses, 
	return slot->sl_status;

}



#define NFSD_MIN_REQ_HDR_SEQ_SZ	((\

			2 * 2 + /* credential,verifier: AUTH_NULL, length 0 */ \

			1 +	/* MIN tag is length with zero, only length */ \

			3 +	/* version, opcount, opcode */ \

			XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \

				/* seqid, slotID, slotID, cache */ \

			4 ) * sizeof(__be32))



#define NFSD_MIN_RESP_HDR_SEQ_SZ ((\

			2 +	/* verifier: AUTH_NULL, length 0 */\

			1 +	/* status */ \

			1 +	/* MIN tag is length with zero, only length */ \

			3 +	/* opcount, opcode, opstatus*/ \

			XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \

				/* seqid, slotID, slotID, slotID, status */ \

			5 ) * sizeof(__be32))



static __be32 check_forechannel_attrs(struct nfsd4_channel_attrs fchannel)

{

	return fchannel.maxreq_sz < NFSD_MIN_REQ_HDR_SEQ_SZ

		|| fchannel.maxresp_sz < NFSD_MIN_RESP_HDR_SEQ_SZ;

}



__be32

nfsd4_create_session(struct svc_rqst *rqstp,

		     struct nfsd4_compound_state *cstate,
@@ -1574,6 +1597,10 @@ nfsd4_create_session(struct svc_rqst *rqstp, 
	cr_ses->flags &= ~SESSION4_PERSIST;

	cr_ses->flags &= ~SESSION4_RDMA;



	status = nfserr_toosmall;

	if (check_forechannel_attrs(cr_ses->fore_channel))

		goto out;



	status = nfserr_jukebox;

	new = alloc_init_session(rqstp, conf, cr_ses);

	if (!new)