NFS: add new file handle decoders to in-kernel mountd client

Introduce xdr_stream-based XDR file handle decoders to the in-kernel
mountd client.  These are more careful than the existing decoder
functions about buffer overflows and data type and range checking.

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

1 files changed, 39 insertions, 0 deletions

diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
index 8429885bc729..dd8c6f448eaa 100644
--- a/fs/nfs/mount_clnt.c
+++ b/fs/nfs/mount_clnt.c
@@ -31,6 +31,8 @@
 #define encode_dirpath_sz       (1 + XDR_QUADLEN(MNTPATHLEN))
 #define MNT_status_sz           (1)
 #define MNT_fhs_status_sz       (1)
+#define MNT_fhandle_sz          XDR_QUADLEN(NFS2_FHSIZE)
+#define MNT_fhandle3_sz         (1 + XDR_QUADLEN(NFS3_FHSIZE))
 
 /*
  * XDR argument and result sizes
@@ -272,6 +274,20 @@ static int decode_status(struct xdr_stream *xdr, struct mountres *res)
         return 0;
 }
 
+static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
+{
+        struct nfs_fh *fh = res->fh;
+        __be32 *p;
+
+        p = xdr_inline_decode(xdr, NFS2_FHSIZE);
+        if (unlikely(p == NULL))
+                return -EIO;
+
+        fh->size = NFS2_FHSIZE;
+        memcpy(fh->data, p, NFS2_FHSIZE);
+        return 0;
+}
+
 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
 {
         unsigned int i;
@@ -295,6 +311,29 @@ static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
         return 0;
 }
 
+static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
+{
+        struct nfs_fh *fh = res->fh;
+        u32 size;
+        __be32 *p;
+
+        p = xdr_inline_decode(xdr, sizeof(size));
+        if (unlikely(p == NULL))
+                return -EIO;
+
+        size = ntohl(*p++);
+        if (size > NFS3_FHSIZE || size == 0)
+                return -EIO;
+
+        p = xdr_inline_decode(xdr, size);
+        if (unlikely(p == NULL))
+                return -EIO;
+
+        fh->size = size;
+        memcpy(fh->data, p, size);
+        return 0;
+}
+
 static int xdr_decode_fhstatus3(struct rpc_rqst *req, __be32 *p,
                                 struct mnt_fhstatus *res)
 {