[Spice-devel] [vdagent-win PATCH v2] Avoid to use names with reserved characters.

[Frediano Ziglio]

> 
> Hi,
> 
> On Mon, Sep 05, 2016 at 12:36:26PM +0100, Frediano Ziglio wrote:
> > Some characters are reserved and should not be used in Windows
> > independently by the file system used.
> > This avoid to use paths in the filename which could lead to some
> > nasty hacks (like names like "..\hack.txt").
> 
> True :)
> 
> Although, I wonder if we should not *change* the filename and proceed
> with the file-transfer?
> 

What do you mean here? Kind of change "..\hack.txt" to "hack.txt" ?

> >
> > ":" is used to separate filenames from stream names and can be used
> > to create hidden streams. Also is used for drive separator (A:)
> > or device names (NUL:).
> > "/" and "\" are reserved for components (directory, filename, drive,
> > share, server) separators.
> > "*" and "?" are wildcards (which on Windows are supported by
> > different APIs too).
> > "<", ">" and "|" are reserved for shell usage.
> >
> > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> > ---
> >  vdagent/file_xfer.cpp | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/vdagent/file_xfer.cpp b/vdagent/file_xfer.cpp
> > index 0e90ebe..2072277 100644
> > --- a/vdagent/file_xfer.cpp
> > +++ b/vdagent/file_xfer.cpp
> > @@ -65,6 +65,10 @@ void FileXfer::handle_start(VDAgentFileXferStartMessage*
> > start,
> >          return;
> >      }
> >      vd_printf("%u %s (%" PRIu64 ")", start->id, file_name, file_size);
> > +    if (strcspn(file_name, "<>:\"/\\|?*") != strlen(file_name)) {
> > +        vd_printf("filename contains invalid characters");
> > +        return;
> > +    }
> 
> I would add in the commit log that this endup returning error to the
> user with VD_AGENT_FILE_XFER_STATUS_ERROR as status (just to be clear as
> we can't see that in the patch itself)
> 
> Cheers,
>   toso
> 

Done, I added:

"The return statement cause the file transfer to be aborted with
VD_AGENT_FILE_XFER_STATUS_ERROR as status."

> >      if (!as_user.begin()) {
> >          vd_printf("as_user failed");
> >          return;

Frediano