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Commit a8095f7e authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: size-checking cleanup 



Better variable name, some comments, etc.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent ea8d7720

fs/nfsd/nfs4proc.c

+6 −3
Original line number Original line Diff line number Diff line
@@ -1279,7 +1279,6 @@ nfsd4_proc_compound(struct svc_rqst *rqstp, 
	struct nfsd4_compound_state *cstate = &resp->cstate;

	struct nfsd4_compound_state *cstate = &resp->cstate;

	struct svc_fh *current_fh = &cstate->current_fh;

	struct svc_fh *current_fh = &cstate->current_fh;

	struct svc_fh *save_fh = &cstate->save_fh;

	struct svc_fh *save_fh = &cstate->save_fh;

	u32		plen = 0;

	__be32		status;

	__be32		status;





	svcxdr_init_encode(rqstp, resp);

	svcxdr_init_encode(rqstp, resp);
@@ -1349,9 +1348,13 @@ nfsd4_proc_compound(struct svc_rqst *rqstp, 




		/* If op is non-idempotent */

		/* If op is non-idempotent */

		if (opdesc->op_flags & OP_MODIFIES_SOMETHING) {

		if (opdesc->op_flags & OP_MODIFIES_SOMETHING) {

			plen = opdesc->op_rsize_bop(rqstp, op);

			/*

			/*

			 * If there's still another operation, make sure

			 * Don't execute this op if we couldn't encode a

			 * succesful reply:

			 */

			u32 plen = opdesc->op_rsize_bop(rqstp, op);

			/*

			 * Plus if there's another operation, make sure

			 * we'll have space to at least encode an error:

			 * we'll have space to at least encode an error:

			 */

			 */

			if (resp->opcnt < args->opcnt)

			if (resp->opcnt < args->opcnt)

fs/nfsd/nfs4xdr.c

+15 −14
Original line number Original line Diff line number Diff line
@@ -3739,35 +3739,36 @@ static nfsd4_enc nfsd4_enc_ops[] = { 
};

};





/*

/*

 * Calculate the total amount of memory that the compound response has taken

 * Calculate whether we still have space to encode repsize bytes.

 * after encoding the current operation with pad.

 * There are two considerations:

 *     - For NFS versions >=4.1, the size of the reply must stay within

 *       session limits

 *     - For all NFS versions, we must stay within limited preallocated

 *       buffer space.

 *

 *

 * pad: if operation is non-idempotent, pad was calculate by op_rsize_bop()

 * This is called before the operation is processed, so can only provide

 *      which was specified at nfsd4_operation, else pad is zero.

 * an upper estimate.  For some nonidempotent operations (such as

 *

 * getattr), it's not necessarily a problem if that estimate is wrong,

 * Compare this length to the session se_fmaxresp_sz and se_fmaxresp_cached.

 * as we can fail it after processing without significant side effects.

 *

 * Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so

 * will be at least a page and will therefore hold the xdr_buf head.

 */

 */

__be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 pad)

__be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)

{

{

	struct xdr_buf *buf = &resp->rqstp->rq_res;

	struct xdr_buf *buf = &resp->rqstp->rq_res;

	struct nfsd4_session *session = resp->cstate.session;

	struct nfsd4_session *session = resp->cstate.session;

	struct nfsd4_slot *slot = resp->cstate.slot;

	int slack_bytes = (char *)resp->xdr.end - (char *)resp->xdr.p;

	int slack_bytes = (char *)resp->xdr.end - (char *)resp->xdr.p;





	if (nfsd4_has_session(&resp->cstate)) {

	if (nfsd4_has_session(&resp->cstate)) {

		struct nfsd4_slot *slot = resp->cstate.slot;





		if (buf->len + pad > session->se_fchannel.maxresp_sz)

		if (buf->len + respsize > session->se_fchannel.maxresp_sz)

			return nfserr_rep_too_big;

			return nfserr_rep_too_big;





		if ((slot->sl_flags & NFSD4_SLOT_CACHETHIS) &&

		if ((slot->sl_flags & NFSD4_SLOT_CACHETHIS) &&

		    buf->len + pad > session->se_fchannel.maxresp_cached)

		    buf->len + respsize > session->se_fchannel.maxresp_cached)

			return nfserr_rep_too_big_to_cache;

			return nfserr_rep_too_big_to_cache;

	}

	}





	if (pad > slack_bytes) {

	if (respsize > slack_bytes) {

		WARN_ON_ONCE(nfsd4_has_session(&resp->cstate));

		WARN_ON_ONCE(nfsd4_has_session(&resp->cstate));

		return nfserr_resource;

		return nfserr_resource;

	}

	}