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);