NFS: Use unsigned intermediates for manipulating header lengths (NFSv3 XDR)

Clean up: prevent length underflow and mixed sign comparisons when
unmarshalling NFS version 3 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, 15 insertions, 12 deletions

diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 616d3267b7e7..3917e2fa4e40 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -506,9 +506,9 @@ nfs3_xdr_readdirres(struct rpc_rqst *req, __be32 *p, struct nfs3_readdirres *res
         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
         struct kvec *iov = rcvbuf->head;
         struct page **page;
-        int hdrlen, recvd;
+        size_t hdrlen;
+        u32 len, recvd, pglen;
         int status, nr;
-        unsigned int len, pglen;
         __be32 *entry, *end, *kaddr;
 
         status = ntohl(*p++);
@@ -527,7 +527,7 @@ nfs3_xdr_readdirres(struct rpc_rqst *req, __be32 *p, struct nfs3_readdirres *res
         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");
@@ -549,7 +549,7 @@ nfs3_xdr_readdirres(struct rpc_rqst *req, __be32 *p, struct nfs3_readdirres *res
                 len = ntohl(*p++);              /* string length */
                 p += XDR_QUADLEN(len) + 2;      /* name + cookie */
                 if (len > NFS3_MAXNAMLEN) {
-                        dprintk("NFS: giant filename in readdir (len %x)!\n",
+                        dprintk("NFS: giant filename in readdir (len 0x%x)!\n",
                                                 len);
                         goto err_unmap;
                 }
@@ -570,7 +570,7 @@ nfs3_xdr_readdirres(struct rpc_rqst *req, __be32 *p, struct nfs3_readdirres *res
                                 len = ntohl(*p++);
                                 if (len > NFS3_FHSIZE) {
                                         dprintk("NFS: giant filehandle in "
-                                                "readdir (len %x)!\n", len);
+                                                "readdir (len 0x%x)!\n", len);
                                         goto err_unmap;
                                 }
                                 p += XDR_QUADLEN(len);
@@ -815,7 +815,8 @@ nfs3_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
 {
         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;
 
@@ -827,7 +828,7 @@ nfs3_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
 
         /* 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;
         }
@@ -835,7 +836,7 @@ nfs3_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
         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. "
@@ -863,7 +864,9 @@ static int
 nfs3_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
 {
         struct kvec *iov = req->rq_rcv_buf.head;
-        int     status, count, ocount, recvd, hdrlen;
+        size_t hdrlen;
+        u32 count, ocount, recvd;
+        int status;
 
         status = ntohl(*p++);
         p = xdr_decode_post_op_attr(p, res->fattr);
@@ -871,7 +874,7 @@ nfs3_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
         if (status != 0)
                 return -nfs_stat_to_errno(status);
 
-        /* Decode reply could and EOF flag. NFSv3 is somewhat redundant
+        /* Decode reply count and EOF flag. NFSv3 is somewhat redundant
          * in that it puts the count both in the res struct and in the
          * opaque data count. */
         count    = ntohl(*p++);
@@ -886,7 +889,7 @@ nfs3_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");
@@ -896,7 +899,7 @@ nfs3_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;
                 res->eof = 0;
         }