[PATCH] kNFSd: Correct error returns.

From: NeilBrown <neilb@cse.unsw.edu.au>

Call decode_fattr on writable attributes to check for xdr errors, incorrect
utf8, etc.

fs/nfsd/nfs4proc.c

@@ -584,8 +584,9 @@ nfsd4_verify(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_ver
 
 	if ((verify->ve_bmval[0] & ~NFSD_SUPPORTED_ATTRS_WORD0)
 	    || (verify->ve_bmval[1] & ~NFSD_SUPPORTED_ATTRS_WORD1))
-		return nfserr_notsupp;
-	if (verify->ve_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1)
+		return nfserr_attrnotsupp;
+	if ((verify->ve_bmval[0] & FATTR4_WORD0_RDATTR_ERROR)
+	    || (verify->ve_bmval[1] & NFSD_WRITEONLY_ATTRS_WORD1))
 		return nfserr_inval;
 	if (verify->ve_attrlen & 3)
 		return nfserr_inval;

fs/nfsd/nfs4xdr.c

@@ -908,10 +908,31 @@ nfsd4_decode_setclientid_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_s
 static int
 nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify)
 {
+#if 0
+	struct nfsd4_compoundargs save = {
+		.p = argp->p,
+		.end = argp->end,
+		.rqstp = argp->rqstp,
+	};
+	u32             ve_bmval[2];
+	struct iattr    ve_iattr;           /* request */
+	struct nfs4_acl *ve_acl;            /* request */
+#endif
 	DECODE_HEAD;
 
 	if ((status = nfsd4_decode_bitmap(argp, verify->ve_bmval)))
 		goto out;
+
+	/* For convenience's sake, we compare raw xdr'd attributes in
+	 * nfsd4_proc_verify; however we still decode here just to return
+	 * correct error in case of bad xdr. */
+#if 0
+	status = nfsd4_decode_fattr(ve_bmval, &ve_iattr, &ve_acl);
+	if (status == nfserr_inval) {
+		status = nfserrno(status);
+		goto out;
+	}
+#endif
 	READ_BUF(4);
 	READ32(verify->ve_attrlen);
 	READ_BUF(verify->ve_attrlen);

include/linux/nfsd/nfsd.h

@@ -191,6 +191,7 @@ void		nfsd_lockd_shutdown(void);
 #define	nfserr_symlink		__constant_htonl(NFSERR_SYMLINK)
 #define	nfserr_not_same		__constant_htonl(NFSERR_NOT_SAME)
 #define	nfserr_restorefh	__constant_htonl(NFSERR_RESTOREFH)
+#define	nfserr_attrnotsupp	__constant_htonl(NFSERR_ATTRNOTSUPP)
 #define	nfserr_bad_xdr		__constant_htonl(NFSERR_BAD_XDR)
 #define	nfserr_openmode		__constant_htonl(NFSERR_OPENMODE)