nfsd4: move access/deny validity checks to xdr code

I'd rather put more of these sorts of checks into standardized xdr
decoders for the various types rather than have them cluttering up the
core logic in nfs4proc.c and nfs4state.c.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -2418,31 +2418,6 @@ find_file(struct inode *ino)
 	return NULL;
 }
 
-static inline int access_valid(u32 x, u32 minorversion)
-{
-	if ((x & NFS4_SHARE_ACCESS_MASK) < NFS4_SHARE_ACCESS_READ)
-		return 0;
-	if ((x & NFS4_SHARE_ACCESS_MASK) > NFS4_SHARE_ACCESS_BOTH)
-		return 0;
-	x &= ~NFS4_SHARE_ACCESS_MASK;
-	if (minorversion && x) {
-		if ((x & NFS4_SHARE_WANT_MASK) > NFS4_SHARE_WANT_CANCEL)
-			return 0;
-		if ((x & NFS4_SHARE_WHEN_MASK) > NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED)
-			return 0;
-		x &= ~(NFS4_SHARE_WANT_MASK | NFS4_SHARE_WHEN_MASK);
-	}
-	if (x)
-		return 0;
-	return 1;
-}
-
-static inline int deny_valid(u32 x)
-{
-	/* Note: unlike access bits, deny bits may be zero. */
-	return x <= NFS4_SHARE_DENY_BOTH;
-}
-
 /*
  * Called to check deny when READ with all zero stateid or
  * WRITE with all zero or all one stateid
@@ -2918,10 +2893,6 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 	struct nfs4_delegation *dp = NULL;
 	__be32 status;
 
-	status = nfserr_inval;
-	if (!access_valid(open->op_share_access, resp->cstate.minorversion)
-			|| !deny_valid(open->op_share_deny))
-		goto out;
 	/*
 	 * Lookup file; if found, lookup stateid and check open request,
 	 * and check for delegations in the process of being recalled.
@@ -3571,9 +3542,6 @@ nfsd4_open_downgrade(struct svc_rqst *rqstp,
 			(int)cstate->current_fh.fh_dentry->d_name.len,
 			cstate->current_fh.fh_dentry->d_name.name);
 
-	if (!access_valid(od->od_share_access, cstate->minorversion)
-			|| !deny_valid(od->od_share_deny))
-		return nfserr_inval;
 	/* We don't yet support WANT bits: */
 	od->od_share_access &= NFS4_SHARE_ACCESS_MASK;
 

fs/nfsd/nfs4xdr.c

@@ -639,6 +639,64 @@ nfsd4_decode_lookup(struct nfsd4_compoundargs *argp, struct nfsd4_lookup *lookup
 	DECODE_TAIL;
 }
 
+static __be32 nfsd4_decode_share_access(struct nfsd4_compoundargs *argp, u32 *x)
+{
+	__be32 *p;
+	u32 w;
+
+	READ_BUF(4);
+	READ32(w);
+	*x = w;
+	switch (w & NFS4_SHARE_ACCESS_MASK) {
+	case NFS4_SHARE_ACCESS_READ:
+	case NFS4_SHARE_ACCESS_WRITE:
+	case NFS4_SHARE_ACCESS_BOTH:
+		break;
+	default:
+		return nfserr_bad_xdr;
+	}
+	w &= !NFS4_SHARE_ACCESS_MASK;
+	if (!w)
+		return nfs_ok;
+	if (!argp->minorversion)
+		return nfserr_bad_xdr;
+	switch (w & NFS4_SHARE_WANT_MASK) {
+	case NFS4_SHARE_WANT_NO_PREFERENCE:
+	case NFS4_SHARE_WANT_READ_DELEG:
+	case NFS4_SHARE_WANT_WRITE_DELEG:
+	case NFS4_SHARE_WANT_ANY_DELEG:
+	case NFS4_SHARE_WANT_NO_DELEG:
+	case NFS4_SHARE_WANT_CANCEL:
+		break;
+	default:
+		return nfserr_bad_xdr;
+	}
+	w &= !NFS4_SHARE_WANT_MASK;
+	if (!w)
+		return nfs_ok;
+	switch (w) {
+	case NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL:
+	case NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED:
+		return nfs_ok;
+	}
+xdr_error:
+	return nfserr_bad_xdr;
+}
+
+static __be32 nfsd4_decode_share_deny(struct nfsd4_compoundargs *argp, u32 *x)
+{
+	__be32 *p;
+
+	READ_BUF(4);
+	READ32(*x);
+	/* Note: unlinke access bits, deny bits may be zero. */
+	if (*x & !NFS4_SHARE_DENY_BOTH)
+		return nfserr_bad_xdr;
+	return nfs_ok;
+xdr_error:
+	return nfserr_bad_xdr;
+}
+
 static __be32
 nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 {
@@ -649,10 +707,15 @@ nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 	open->op_openowner = NULL;
 
 	/* seqid, share_access, share_deny, clientid, ownerlen */
-	READ_BUF(16 + sizeof(clientid_t));
+	READ_BUF(4);
 	READ32(open->op_seqid);
-	READ32(open->op_share_access);
-	READ32(open->op_share_deny);
+	status = nfsd4_decode_share_access(argp, &open->op_share_access);
+	if (status)
+		goto xdr_error;
+	status = nfsd4_decode_share_deny(argp, &open->op_share_deny);
+	if (status)
+		goto xdr_error;
+	READ_BUF(sizeof(clientid_t) + 4);
 	COPYMEM(&open->op_clientid, sizeof(clientid_t));
 	READ32(open->op_owner.len);
 
@@ -753,11 +816,14 @@ nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_d
 	status = nfsd4_decode_stateid(argp, &open_down->od_stateid);
 	if (status)
 		return status;
-	READ_BUF(12);
+	READ_BUF(4);
 	READ32(open_down->od_seqid);
-	READ32(open_down->od_share_access);
-	READ32(open_down->od_share_deny);
-
+	status = nfsd4_decode_share_access(argp, &open_down->od_share_access);
+	if (status)
+		return status;
+	status = nfsd4_decode_share_deny(argp, &open_down->od_share_deny);
+	if (status)
+		return status;
 	DECODE_TAIL;
 }