Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6

Pull CIFS fixes from Steve French:
 "A fix for the problem which Al spotted in cifs_writev and a followup
  (noticed when fixing CVE-2014-0069) patch to ensure that cifs never
  sends more than the smb frame length over the socket (as we saw with
  that cifs_iovec_write problem that Jeff fixed last month)"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: mask off top byte in get_rfc1002_length()
  cifs: sanity check length of data to send before sending
  CIFS: Fix wrong pos argument of cifs_find_lock_conflict

3 files changed, 36 insertions, 19 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index cf32f0393369..c0f3718b77a8 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -513,7 +513,7 @@ struct cifs_mnt_data {
 static inline unsigned int
 get_rfc1002_length(void *buf)
 {
-        return be32_to_cpu(*((__be32 *)buf));
+        return be32_to_cpu(*((__be32 *)buf)) & 0xffffff;
 }
 
 static inline void
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 53c15074bb36..834fce759d80 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2579,31 +2579,19 @@ cifs_writev(struct kiocb *iocb, const struct iovec *iov,
         struct cifsInodeInfo *cinode = CIFS_I(inode);
         struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
         ssize_t rc = -EACCES;
+        loff_t lock_pos = pos;
 
-        BUG_ON(iocb->ki_pos != pos);
-
+        if (file->f_flags & O_APPEND)
+                lock_pos = i_size_read(inode);
         /*
          * We need to hold the sem to be sure nobody modifies lock list
          * with a brlock that prevents writing.
          */
         down_read(&cinode->lock_sem);
-        if (!cifs_find_lock_conflict(cfile, pos, iov_length(iov, nr_segs),
+        if (!cifs_find_lock_conflict(cfile, lock_pos, iov_length(iov, nr_segs),
                                      server->vals->exclusive_lock_type, NULL,
-                                     CIFS_WRITE_OP)) {
-                mutex_lock(&inode->i_mutex);
-                rc = __generic_file_aio_write(iocb, iov, nr_segs,
-                                               &iocb->ki_pos);
-                mutex_unlock(&inode->i_mutex);
-        }
-
-        if (rc > 0) {
-                ssize_t err;
-
-                err = generic_write_sync(file, iocb->ki_pos - rc, rc);
-                if (err < 0)
-                        rc = err;
-        }
-
+                                     CIFS_WRITE_OP))
+                rc = generic_file_aio_write(iocb, iov, nr_segs, pos);
         up_read(&cinode->lock_sem);
         return rc;
 }
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index b37570952846..18cd5650a5fc 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -270,6 +270,26 @@ cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
                 iov->iov_len = rqst->rq_pagesz;
 }
 
+static unsigned long
+rqst_len(struct smb_rqst *rqst)
+{
+        unsigned int i;
+        struct kvec *iov = rqst->rq_iov;
+        unsigned long buflen = 0;
+
+        /* total up iov array first */
+        for (i = 0; i < rqst->rq_nvec; i++)
+                buflen += iov[i].iov_len;
+
+        /* add in the page array if there is one */
+        if (rqst->rq_npages) {
+                buflen += rqst->rq_pagesz * (rqst->rq_npages - 1);
+                buflen += rqst->rq_tailsz;
+        }
+
+        return buflen;
+}
+
 static int
 smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 {
@@ -277,6 +297,7 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
         struct kvec *iov = rqst->rq_iov;
         int n_vec = rqst->rq_nvec;
         unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
+        unsigned long send_length;
         unsigned int i;
         size_t total_len = 0, sent;
         struct socket *ssocket = server->ssocket;
@@ -285,6 +306,14 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
         if (ssocket == NULL)
                 return -ENOTSOCK;
 
+        /* sanity check send length */
+        send_length = rqst_len(rqst);
+        if (send_length != smb_buf_length + 4) {
+                WARN(1, "Send length mismatch(send_length=%lu smb_buf_length=%u)\n",
+                        send_length, smb_buf_length);
+                return -EIO;
+        }
+
         cifs_dbg(FYI, "Sending smb: smb_len=%u\n", smb_buf_length);
         dump_smb(iov[0].iov_base, iov[0].iov_len);