[Spice-devel] [PATCH vd_agent_win] Use sprintf_s instead of sprintf to not crash

[Frediano Ziglio]

> 
> ---
>  vdagent/file_xfer.cpp | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/vdagent/file_xfer.cpp b/vdagent/file_xfer.cpp
> index de1aea1..de98d50 100644
> --- a/vdagent/file_xfer.cpp
> +++ b/vdagent/file_xfer.cpp
> @@ -113,8 +113,8 @@ void FileXfer::handle_start(VDAgentFileXferStartMessage*
> start,
>          if (attempt == 0) {
>              strcpy(dest_filename, file_name);
>          } else {
> -            sprintf(dest_filename, "%.*s (%d)%s", int(extension -
> file_name), file_name,
> -                    attempt, extension);
> +            sprintf_s(dest_filename, SPICE_N_ELEMENTS(file_name) +
> POSTFIX_LEN,
> +                      "%.*s (%d)%s", int(extension - file_name), file_name,
> attempt, extension);
>          }
>          if ((MultiByteToWideChar(CP_UTF8, 0, dest_filename, -1, file_path +
>          wlen, MAX_PATH - wlen)) == 0) {
>              vd_printf("failed converting file_name:%s to WideChar",
>              dest_filename);

As far as I know dest_filename is allocate big enough to avoid the
overflow.
Did it crash for you or just a warning from the compiler?

This would be easier

            sprintf_s(dest_filename, SPICE_N_ELEMENTS(dest_filename),
                      "%.*s (%d)%s", int(extension - file_name), file_name, attempt, extension);

without computing again the length.

Frediano