Re: [bug report] Handle mismatched open calls

[Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Thu, 2017-04-06 at 12:11 +0300, Dan Carpenter wrote:
> Hello Sachin Prabhu,
> 
> The patch 96b75d0508f8: "Handle mismatched open calls" from Mar 3,
> 2017, leads to the following static checker warning:
> 
> 	fs/cifs/cifssmb.c:1530 cifs_readv_receive()
> 	error: potential NULL dereference 'server->smallbuf'.
> 
> fs/cifs/cifssmb.c
>   1519          cifs_dbg(FYI, "0: iov_base=%p iov_len=%u\n",
>   1520                   rdata->iov[0].iov_base, server->total_read);
>   1521  
>   1522          mid->resp_buf = server->smallbuf;
>   1523          server->smallbuf = NULL;
>                 ^^^^^^^^^^^^^^^^^^^^^^^
> We set this to NULL here
> 
>   1524  
>   1525          /* how much data is in the response? */
>   1526          data_len = server->ops->read_data_length(buf);
>   1527          if (data_offset + data_len > buflen) {
>   1528                  /* data_len is corrupt -- discard frame */
>   1529                  rdata->result = -EIO;
>   1530                  return cifs_readv_discard(server, mid);
>                                                   ^^^^^^
> but we need it here.
> 
>   1531          }
>   1532  
>   1533          length = rdata->read_into_pages(server, rdata,
> data_len);
>   1534          if (length < 0)
>   1535                  return length;
> 
> regards,
> dan carpenter

Thanks Dan,

We should probably move that piece of code to the bottom of the
function just before we return.

Sachin Prabhu