NFS: Update MNT and MNT3 reply decoding functions

Solder xdr_stream-based XDR decoding functions into the in-kernel mountd
client that are more careful about checking data types and watching for
buffer overflows.  The new MNT3 decoder includes support for auth-flavor
list decoding.

The "_sz" macro for MNT3 replies was missing the size of the file handle.
I've added this back, and included the size of the auth flavor array.

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

1 files changed, 49 insertions, 14 deletions

diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
index ed0a27ed538d..618d815c3093 100644
--- a/fs/nfs/mount_clnt.c
+++ b/fs/nfs/mount_clnt.c
@@ -39,6 +39,9 @@
  * XDR argument and result sizes
  */
 #define MNT_enc_dirpath_sz      encode_dirpath_sz
+#define MNT_dec_mountres_sz     (MNT_status_sz + MNT_fhandle_sz)
+#define MNT_dec_mountres3_sz    (MNT_status_sz + MNT_fhandle_sz + \
+                                 MNT_authflav3_sz)
 
 /*
  * Defined by RFC 1094, section A.5
@@ -140,8 +143,10 @@ struct mnt_fhstatus {
  */
 int nfs_mount(struct nfs_mount_request *info)
 {
-        struct mnt_fhstatus     result = {
-                .fh             = info->fh
+        struct mountres result = {
+                .fh             = info->fh,
+                .auth_count     = info->auth_flav_len,
+                .auth_flavors   = info->auth_flavs,
         };
         struct rpc_message msg  = {
                 .rpc_argp       = info->dirpath,
@@ -180,7 +185,7 @@ int nfs_mount(struct nfs_mount_request *info)
 
         if (status < 0)
                 goto out_call_err;
-        if (result.status != 0)
+        if (result.errno != 0)
                 goto out_mnt_err;
 
         dprintk("NFS: MNT request succeeded\n");
@@ -191,16 +196,16 @@ out:
 
 out_clnt_err:
         status = PTR_ERR(mnt_clnt);
-        dprintk("NFS: failed to create RPC client, status=%d\n", status);
+        dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
         goto out;
 
 out_call_err:
-        dprintk("NFS: failed to start MNT request, status=%d\n", status);
+        dprintk("NFS: MNT request failed, status=%d\n", status);
         goto out;
 
 out_mnt_err:
-        dprintk("NFS: MNT server returned result %d\n", result.status);
-        status = nfs_stat_to_errno(result.status);
+        dprintk("NFS: MNT server returned result %d\n", result.errno);
+        status = result.errno;
         goto out;
 }
 
@@ -291,6 +296,20 @@ static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
         return 0;
 }
 
+static int mnt_dec_mountres(struct rpc_rqst *req, __be32 *p,
+                            struct mountres *res)
+{
+        struct xdr_stream xdr;
+        int status;
+
+        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
+
+        status = decode_status(&xdr, res);
+        if (unlikely(status != 0 || res->errno != 0))
+                return status;
+        return decode_fhandle(&xdr, res);
+}
+
 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
 {
         unsigned int i;
@@ -371,6 +390,25 @@ static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
         return 0;
 }
 
+static int mnt_dec_mountres3(struct rpc_rqst *req, __be32 *p,
+                             struct mountres *res)
+{
+        struct xdr_stream xdr;
+        int status;
+
+        xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
+
+        status = decode_fhs_status(&xdr, res);
+        if (unlikely(status != 0 || res->errno != 0))
+                return status;
+        status = decode_fhandle3(&xdr, res);
+        if (unlikely(status != 0)) {
+                res->errno = -EBADHANDLE;
+                return 0;
+        }
+        return decode_auth_flavors(&xdr, res);
+}
+
 static int xdr_decode_fhstatus3(struct rpc_rqst *req, __be32 *p,
                                 struct mnt_fhstatus *res)
 {
@@ -388,16 +426,13 @@ static int xdr_decode_fhstatus3(struct rpc_rqst *req, __be32 *p,
         return 0;
 }
 
-#define MNT_fhstatus_sz         (1 + 8)
-#define MNT_fhstatus3_sz        (1 + 16)
-
 static struct rpc_procinfo mnt_procedures[] = {
         [MOUNTPROC_MNT] = {
                 .p_proc         = MOUNTPROC_MNT,
                 .p_encode       = (kxdrproc_t)mnt_enc_dirpath,
-                .p_decode       = (kxdrproc_t) xdr_decode_fhstatus,
+                .p_decode       = (kxdrproc_t)mnt_dec_mountres,
                 .p_arglen       = MNT_enc_dirpath_sz,
-                .p_replen       = MNT_fhstatus_sz,
+                .p_replen       = MNT_dec_mountres_sz,
                 .p_statidx      = MOUNTPROC_MNT,
                 .p_name         = "MOUNT",
         },
@@ -407,9 +442,9 @@ static struct rpc_procinfo mnt3_procedures[] = {
         [MOUNTPROC3_MNT] = {
                 .p_proc         = MOUNTPROC3_MNT,
                 .p_encode       = (kxdrproc_t)mnt_enc_dirpath,
-                .p_decode       = (kxdrproc_t) xdr_decode_fhstatus3,
+                .p_decode       = (kxdrproc_t)mnt_dec_mountres3,
                 .p_arglen       = MNT_enc_dirpath_sz,
-                .p_replen       = MNT_fhstatus3_sz,
+                .p_replen       = MNT_dec_mountres3_sz,
                 .p_statidx      = MOUNTPROC3_MNT,
                 .p_name         = "MOUNT",
         },