NFS: Use unsigned intermediates for manipulating header lengths (NFSv2 XDR)

Clean up: prevent length underflow and mixed sign comparisons when
unmarshalling NFS version 2 read, readdir, and readlink replies.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 14 insertions, 10 deletions

diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index 668ab96c7b59..1f7ea675e0c5 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -262,7 +262,9 @@ static int
 nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
 {
         struct kvec *iov = req->rq_rcv_buf.head;
-        int     status, count, recvd, hdrlen;
+        size_t hdrlen;
+        u32 count, recvd;
+        int status;
 
         if ((status = ntohl(*p++)))
                 return -nfs_stat_to_errno(status);
@@ -273,7 +275,7 @@ nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
         hdrlen = (u8 *) p - (u8 *) iov->iov_base;
         if (iov->iov_len < hdrlen) {
                 dprintk("NFS: READ reply header overflowed:"
-                                "length %d > %Zu\n", hdrlen, iov->iov_len);
+                                "length %Zu > %Zu\n", hdrlen, iov->iov_len);
                 return -errno_NFSERR_IO;
         } else if (iov->iov_len != hdrlen) {
                 dprintk("NFS: READ header is short. iovec will be shifted.\n");
@@ -283,11 +285,11 @@ nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
         recvd = req->rq_rcv_buf.len - hdrlen;
         if (count > recvd) {
                 dprintk("NFS: server cheating in read reply: "
-                        "count %d > recvd %d\n", count, recvd);
+                        "count %u > recvd %u\n", count, recvd);
                 count = recvd;
         }
 
-        dprintk("RPC:      readres OK count %d\n", count);
+        dprintk("RPC:      readres OK count %u\n", count);
         if (count < res->count)
                 res->count = count;
 
@@ -423,9 +425,10 @@ nfs_xdr_readdirres(struct rpc_rqst *req, __be32 *p, void *dummy)
         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
         struct kvec *iov = rcvbuf->head;
         struct page **page;
-        int hdrlen, recvd;
+        size_t hdrlen;
+        unsigned int pglen, recvd;
+        u32 len;
         int status, nr;
-        unsigned int len, pglen;
         __be32 *end, *entry, *kaddr;
 
         if ((status = ntohl(*p++)))
@@ -434,7 +437,7 @@ nfs_xdr_readdirres(struct rpc_rqst *req, __be32 *p, void *dummy)
         hdrlen = (u8 *) p - (u8 *) iov->iov_base;
         if (iov->iov_len < hdrlen) {
                 dprintk("NFS: READDIR reply header overflowed:"
-                                "length %d > %Zu\n", hdrlen, iov->iov_len);
+                                "length %Zu > %Zu\n", hdrlen, iov->iov_len);
                 return -errno_NFSERR_IO;
         } else if (iov->iov_len != hdrlen) {
                 dprintk("NFS: READDIR header is short. iovec will be shifted.\n");
@@ -576,7 +579,8 @@ nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
 {
         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
         struct kvec *iov = rcvbuf->head;
-        int hdrlen, len, recvd;
+        size_t hdrlen;
+        u32 len, recvd;
         char    *kaddr;
         int     status;
 
@@ -584,14 +588,14 @@ nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
                 return -nfs_stat_to_errno(status);
         /* Convert length of symlink */
         len = ntohl(*p++);
-        if (len >= rcvbuf->page_len || len <= 0) {
+        if (len >= rcvbuf->page_len) {
                 dprintk("nfs: server returned giant symlink!\n");
                 return -ENAMETOOLONG;
         }
         hdrlen = (u8 *) p - (u8 *) iov->iov_base;
         if (iov->iov_len < hdrlen) {
                 dprintk("NFS: READLINK reply header overflowed:"
-                                "length %d > %Zu\n", hdrlen, iov->iov_len);
+                                "length %Zu > %Zu\n", hdrlen, iov->iov_len);
                 return -errno_NFSERR_IO;
         } else if (iov->iov_len != hdrlen) {
                 dprintk("NFS: READLINK header is short. iovec will be shifted.\n");