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

[Victor Toso]

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?

>
> ":" 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

>      if (!as_user.begin()) {
>          vd_printf("as_user failed");
>          return;
> -- 
> 2.7.4
> 
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