[Spice-devel] [PATCH spice-server] Avoid to access data before a NULL check

[Christophe Fergeau]

Acked-by: Christophe Fergeau <cfergeau at redhat.com>

On Fri, Aug 25, 2017 at 01:44:00PM +0100, Frediano Ziglio wrote:
> If you are testing for NULL data this means that variable could be
> NULL so avoid to access before the check to make sure the check is hit.
> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  server/cursor-channel.c |  3 ++-
>  server/dcc-send.c       | 11 ++++++++---
>  server/stream.c         |  3 ++-
>  3 files changed, 12 insertions(+), 5 deletions(-)
> 
> Would not be easier to remove these checks?
> 
> diff --git a/server/cursor-channel.c b/server/cursor-channel.c
> index 63d6886d..5ece576c 100644
> --- a/server/cursor-channel.c
> +++ b/server/cursor-channel.c
> @@ -182,11 +182,12 @@ static void cursor_pipe_item_free(RedPipeItem *base)
>  static void red_marshall_cursor_init(CursorChannelClient *ccc, SpiceMarshaller *base_marshaller,
>                                       RedPipeItem *pipe_item)
>  {
> +    spice_assert(ccc);
> +
>      CursorChannel *cursor_channel;
>      RedChannelClient *rcc = RED_CHANNEL_CLIENT(ccc);
>      SpiceMsgCursorInit msg;
>  
> -    spice_assert(rcc);
>      cursor_channel = CURSOR_CHANNEL(red_channel_client_get_channel(rcc));
>  
>      red_channel_client_init_send_data(rcc, SPICE_MSG_CURSOR_INIT);
> diff --git a/server/dcc-send.c b/server/dcc-send.c
> index 5a24e693..8e91b8fb 100644
> --- a/server/dcc-send.c
> +++ b/server/dcc-send.c
> @@ -1922,8 +1922,8 @@ static void red_marshall_image(RedChannelClient *rcc,
>                                 SpiceMarshaller *m,
>                                 RedImageItem *item)
>  {
> -    DisplayChannelClient *dcc = DISPLAY_CHANNEL_CLIENT(rcc);
> -    DisplayChannel *display = DCC_TO_DC(dcc);
> +    DisplayChannelClient *dcc;
> +    DisplayChannel *display;
>      SpiceImage red_image;
>      SpiceBitmap bitmap;
>      SpiceChunks *chunks;
> @@ -1932,7 +1932,12 @@ static void red_marshall_image(RedChannelClient *rcc,
>      SpiceMarshaller *src_bitmap_out, *mask_bitmap_out;
>      SpiceMarshaller *bitmap_palette_out, *lzplt_palette_out;
>  
> -    spice_assert(rcc && display && item);
> +    spice_assert(rcc && item);
> +
> +    dcc = DISPLAY_CHANNEL_CLIENT(rcc);
> +
> +    display = DCC_TO_DC(dcc);
> +    spice_assert(display);
>  
>      QXL_SET_IMAGE_ID(&red_image, QXL_IMAGE_GROUP_RED, display_channel_generate_uid(display));
>      red_image.descriptor.type = SPICE_IMAGE_TYPE_BITMAP;
> diff --git a/server/stream.c b/server/stream.c
> index f74a1385..0148d1ed 100644
> --- a/server/stream.c
> +++ b/server/stream.c
> @@ -772,9 +772,10 @@ void stream_agent_stop(StreamAgent *agent)
>  
>  static void red_upgrade_item_free(RedPipeItem *base)
>  {
> +    g_return_if_fail(base != NULL);
> +
>      RedUpgradeItem *item = SPICE_UPCAST(RedUpgradeItem, base);
>  
> -    g_return_if_fail(item != NULL);
>      g_return_if_fail(item->base.refcount == 0);
>  
>      drawable_unref(item->drawable);
> -- 
> 2.13.5
> 
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