[FFmpeg-devel] [PATCH] lavc/vaapi_encode_h265: Suppress the "above array bounds" warning.

[Jun Zhao]

On 2017/4/30 20:47, Mark Thompson wrote:
> On 26/04/17 07:44, Jun Zhao wrote:
>> From f3678e0ceb691b6df5957a2c3d26d4f0d91d4ff5 Mon Sep 17 00:00:00 2001
>> From: Jun Zhao <jun.zhao at intel.com>
>> Date: Wed, 26 Apr 2017 14:00:56 +0800
>> Subject: [PATCH] lavc/vaapi_encode_h265: Suppress the "above array bounds"
>>  warning.
>> MIME-Version: 1.0
>> Content-Type: text/plain; charset=UTF-8
>> Content-Transfer-Encoding: 8bit
>>
>> setting the layer_id_included_flag lead to a potential array out of bounds,
>> build warning message as follow:
>> libavcodec/vaapi_encode_h265.c: In function
>> ‘vaapi_encode_h265_write_sequence_header’:
>> libavcodec/vaapi_encode_h265.c:305:49: warning: array subscript is above
>> array bounds [-Warray-bounds]
> 
> Can you explain what the aim of this is?  You haven't actually set any of the layer_id_included_flag in this patch, so is there more to follow dealing with the layers / layer sets?
> 
> In any case, the dimensions of the array should probably be [MAX_LAYER_SETS][MAX_LAYERS] rather than the current values.  (With MAX_LAYER_SETS having value 1 currently, but more if you intend to add more.)

Because in vaapi_encode_h265_write_vps(), when setting the layer_id_included_flag, the index i start from 1, it's a potential above array bounds issue when MAX_LAYERS == 1. 

> 
>> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
>> ---
>>  libavcodec/vaapi_encode_h265.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c
>> index 6e008b7b9c..1b2a49806b 100644
>> --- a/libavcodec/vaapi_encode_h265.c
>> +++ b/libavcodec/vaapi_encode_h265.c
>> @@ -66,7 +66,7 @@ typedef struct VAAPIEncodeH265MiscSequenceParams {
>>      unsigned int vps_num_layer_sets_minus1;
>>      unsigned int sps_max_sub_layers_minus1;
>>      char sps_temporal_id_nesting_flag;
>> -    char layer_id_included_flag[MAX_LAYERS][64];
>> +    char layer_id_included_flag[MAX_LAYERS+1][64];
>>  
>>      // Profile/tier/level parameters.
>>      char general_profile_compatibility_flag[32];
>> -- 
>> 2.11.0
>>
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