On Thu, 2016-01-14 at 17:12 +0200, Jani Nikula wrote:
> Two errors in a single line. The size was read from the wrong offset,
> and the end index didn't take the five bytes for sequence byte and size
> of sequence into account. Fix it all, and break up the calculations a
> bit to make it clearer.
>
Tested-by: Mika Kahola <mika.kahola@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Reported-by: Mika Kahola <mika.kahola@xxxxxxxxx>
> Fixes: 2a33d93486f2 ("drm/i915/bios: add support for MIPI sequence block v3")
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_bios.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index 12e2f8b8bf9c..bf62a19c8f69 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -842,6 +842,7 @@ static int goto_next_sequence_v3(const u8 *data, int index, int total)
> {
> int seq_end;
> u16 len;
> + u32 size_of_sequence;
>
> /*
> * Could skip sequence based on Size of Sequence alone, but also do some
> @@ -852,14 +853,24 @@ static int goto_next_sequence_v3(const u8 *data, int index, int total)
> return 0;
> }
>
> - seq_end = index + *((const u32 *)(data + 1));
> + /* Skip Sequence Byte. */
> + index++;
> +
> + /*
> + * Size of Sequence. Excludes the Sequence Byte and the size itself,
> + * includes MIPI_SEQ_ELEM_END byte, excludes the final MIPI_SEQ_END
> + * byte.
> + */
> + size_of_sequence = *((const uint32_t *)(data + index));
> + index += 4;
> +
> + seq_end = index + size_of_sequence;
> if (seq_end > total) {
> DRM_ERROR("Invalid sequence size\n");
> return 0;
> }
>
> - /* Skip Sequence Byte and Size of Sequence. */
> - for (index = index + 5; index < total; index += len) {
> + for (; index < total; index += len) {
> u8 operation_byte = *(data + index);
> index++;
>
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