Re: [PATCH 08/15] drm/i915/dsi: be defensive about out of bounds operation byte

[Jani Nikula <jani.nikula@intel.com>]

On Tue, 05 Jan 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Mon, Dec 21, 2015 at 03:10:59PM +0200, Jani Nikula wrote:
>> Untie the VBT based generic panel driver from the VBT parsing, so that
>> the two don't have to be updated in lockstep.
>> 
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 22 +++++++++-------------
>>  1 file changed, 9 insertions(+), 13 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>> index 45512e0df57a..ba5355506590 100644
>> --- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>> +++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
>> @@ -232,11 +232,9 @@ static const u8 *mipi_exec_gpio(struct intel_dsi *intel_dsi, const u8 *data)
>>  typedef const u8 * (*fn_mipi_elem_exec)(struct intel_dsi *intel_dsi,
>>  					const u8 *data);
>>  static const fn_mipi_elem_exec exec_elem[] = {
>> -	NULL, /* reserved */
>> -	mipi_exec_send_packet,
>> -	mipi_exec_delay,
>> -	mipi_exec_gpio,
>> -	NULL, /* status read; later */
>> +	[MIPI_SEQ_ELEM_SEND_PKT] = mipi_exec_send_packet,
>> +	[MIPI_SEQ_ELEM_DELAY] = mipi_exec_delay,
>> +	[MIPI_SEQ_ELEM_GPIO] = mipi_exec_gpio,
>>  };
>>  
>>  /*
>> @@ -264,7 +262,6 @@ static const char *sequence_name(enum mipi_seq seq_id)
>>  static void generic_exec_sequence(struct intel_dsi *intel_dsi, const u8 *data)
>>  {
>>  	fn_mipi_elem_exec mipi_elem_exec;
>> -	int index;
>>  
>>  	if (!data)
>>  		return;
>> @@ -277,15 +274,14 @@ static void generic_exec_sequence(struct intel_dsi *intel_dsi, const u8 *data)
>>  
>>  	/* parse each byte till we reach end of sequence byte - 0x00 */
>>  	while (1) {
>> -		index = *data;
>> -		mipi_elem_exec = exec_elem[index];
>> -		if (!mipi_elem_exec) {
>> -			DRM_ERROR("Unsupported MIPI element, skipping sequence execution\n");
>> +		u8 operation_byte = *data++;
>> +		if (operation_byte >= ARRAY_SIZE(exec_elem) ||
>> +		    !exec_elem[operation_byte]) {
>> +			DRM_ERROR("Unsupported MIPI operation byte %u\n",
>
> Maybe DRM_ERROR in the previous patch too? Just for ocd consistency.
>
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Pushed up to and including this patch. I took the liberty of pushing
as-is, leaving the nitpicks for follow-up. Thanks for the review.

BR,
Jani.


>
>> +				  operation_byte);
>>  			return;
>>  		}
>> -
>> -		/* goto element payload */
>> -		data++;
>> +		mipi_elem_exec = exec_elem[operation_byte];
>>  
>>  		/* execute the element specific rotines */
>>  		data = mipi_elem_exec(intel_dsi, data);
>> -- 
>> 2.1.4
>> 
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center
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