drm/bridge/sii8620: fix potential buffer overflow

[ Upstream commit 9378cecb1ce5d618b8aff4d65113ddcf72fc1011 ]

Buffer overflow error should not occur, as mode_fixup() callback
filters pixel clock value and it should never exceed 600000. However,
current implementation is not obviously safe and relies on
implementation of mode_fixup().

Make 'i' variable never reach unsafe value in order to avoid buffer
overflow error.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: bf1722ca ("drm/bridge/sii8620: rewrite hdmi start sequence")
Signed-off-by: Maciej Purski <m.purski@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1511341718-6974-1-git-send-email-m.purski@samsung.com
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
index 8b17a806ee6fd912d053c8f5f2baa1f34d604ef3..8a8c3ede8821a6b7fce8a68805a150fb37998fd7 100644 (file)
--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -1196,7 +1196,7 @@ static void sii8620_start_hdmi(struct sii8620 *ctx)
                int clk = ctx->pixel_clock * (ctx->use_packed_pixel ? 2 : 3);
                int i;
 
-               for (i = 0; i < ARRAY_SIZE(clk_spec); ++i)
+               for (i = 0; i < ARRAY_SIZE(clk_spec) - 1; ++i)
                        if (clk < clk_spec[i].max_clk)
                                break;