1 files changed, 49 insertions, 15 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 786a4a2cb2d7..59979f0bbd4b 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -167,7 +167,8 @@ nfsd_adjust_nfsd_versions4(void)
 
 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 {
-	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
+	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
+	    change != NFSD_AVAIL)
 		return -1;
 	switch(change) {
 	case NFSD_SET:
@@ -415,23 +416,20 @@ static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
 
 void nfsd_reset_versions(void)
 {
-	int found_one = 0;
 	int i;
 
-	for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
-		if (nfsd_program.pg_vers[i])
-			found_one = 1;
-	}
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (nfsd_vers(i, NFSD_TEST))
+			return;
 
-	if (!found_one) {
-		for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
-			nfsd_program.pg_vers[i] = nfsd_version[i];
-#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
-		for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
-			nfsd_acl_program.pg_vers[i] =
-				nfsd_acl_version[i];
-#endif
-	}
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (i != 4)
+			nfsd_vers(i, NFSD_SET);
+		else {
+			int minor = 0;
+			while (nfsd_minorversion(minor, NFSD_SET) >= 0)
+				minor++;
+		}
 }
 
 /*
@@ -749,6 +747,37 @@ static __be32 map_new_errors(u32 vers, __be32 nfserr)
 	return nfserr;
 }
 
+/*
+ * A write procedure can have a large argument, and a read procedure can
+ * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
+ * reply that can both be larger than a page.  The xdr code has taken
+ * advantage of this assumption to be a sloppy about bounds checking in
+ * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
+ * problem, we enforce these assumptions here:
+ */
+static bool nfs_request_too_big(struct svc_rqst *rqstp,
+				struct svc_procedure *proc)
+{
+	/*
+	 * The ACL code has more careful bounds-checking and is not
+	 * susceptible to this problem:
+	 */
+	if (rqstp->rq_prog != NFS_PROGRAM)
+		return false;
+	/*
+	 * Ditto NFSv4 (which can in theory have argument and reply both
+	 * more than a page):
+	 */
+	if (rqstp->rq_vers >= 4)
+		return false;
+	/* The reply will be small, we're OK: */
+	if (proc->pc_xdrressize > 0 &&
+	    proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
+		return false;
+
+	return rqstp->rq_arg.len > PAGE_SIZE;
+}
+
 int
 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 {
@@ -761,6 +790,11 @@ nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 				rqstp->rq_vers, rqstp->rq_proc);
 	proc = rqstp->rq_procinfo;
 
+	if (nfs_request_too_big(rqstp, proc)) {
+		dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
+		*statp = rpc_garbage_args;
+		return 1;
+	}
 	/*
 	 * Give the xdr decoder a chance to change this if it wants
 	 * (necessary in the NFSv4.0 compound case)