Re: [PATCH v4 2/4] media: venus: hfi_parser: refactor hfi packet parsing logic

[Vikash Garodia <quic_vgarodia@quicinc.com>]

On 2/20/2025 8:50 PM, Hans Verkuil wrote:
> On 2/7/25 09:24, Vikash Garodia wrote:
>> words_count denotes the number of words in total payload, while data
>> points to payload of various property within it. When words_count
>> reaches last word, data can access memory beyond the total payload. This
>> can lead to OOB access. With this patch, the utility api for handling
>> individual properties now returns the size of data consumed. Accordingly
>> remaining bytes are calculated before parsing the payload, thereby
>> eliminates the OOB access possibilities.
>>
>> Cc: stable@vger.kernel.org
>> Fixes: 1a73374a04e5 ("media: venus: hfi_parser: add common capability parser")
>> Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
>> ---
>>  drivers/media/platform/qcom/venus/hfi_parser.c | 95 +++++++++++++++++++-------
>>  1 file changed, 69 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/venus/hfi_parser.c b/drivers/media/platform/qcom/venus/hfi_parser.c
>> index 1cc17f3dc8948160ea6c3015d2c03e475b8aa29e..404c527329c5fa89ee885a6ad15620c9c90a99e4 100644
>> --- a/drivers/media/platform/qcom/venus/hfi_parser.c
>> +++ b/drivers/media/platform/qcom/venus/hfi_parser.c
>> @@ -63,7 +63,7 @@ fill_buf_mode(struct hfi_plat_caps *cap, const void *data, unsigned int num)
>>  		cap->cap_bufs_mode_dynamic = true;
>>  }
>>  
>> -static void
>> +static int
>>  parse_alloc_mode(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  {
>>  	struct hfi_buffer_alloc_mode_supported *mode = data;
>> @@ -71,7 +71,7 @@ parse_alloc_mode(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  	u32 *type;
>>  
>>  	if (num_entries > MAX_ALLOC_MODE_ENTRIES)
>> -		return;
>> +		return -EINVAL;
>>  
>>  	type = mode->data;
>>  
>> @@ -83,6 +83,8 @@ parse_alloc_mode(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  
>>  		type++;
>>  	}
>> +
>> +	return sizeof(*mode);
>>  }
>>  
>>  static void fill_profile_level(struct hfi_plat_caps *cap, const void *data,
>> @@ -97,7 +99,7 @@ static void fill_profile_level(struct hfi_plat_caps *cap, const void *data,
>>  	cap->num_pl += num;
>>  }
>>  
>> -static void
>> +static int
>>  parse_profile_level(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  {
>>  	struct hfi_profile_level_supported *pl = data;
>> @@ -105,12 +107,14 @@ parse_profile_level(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  	struct hfi_profile_level pl_arr[HFI_MAX_PROFILE_COUNT] = {};
>>  
>>  	if (pl->profile_count > HFI_MAX_PROFILE_COUNT)
>> -		return;
>> +		return -EINVAL;
>>  
>>  	memcpy(pl_arr, proflevel, pl->profile_count * sizeof(*proflevel));
>>  
>>  	for_each_codec(core->caps, ARRAY_SIZE(core->caps), codecs, domain,
>>  		       fill_profile_level, pl_arr, pl->profile_count);
>> +
>> +	return pl->profile_count * sizeof(*proflevel) + sizeof(u32);
>>  }
>>  
>>  static void
>> @@ -125,7 +129,7 @@ fill_caps(struct hfi_plat_caps *cap, const void *data, unsigned int num)
>>  	cap->num_caps += num;
>>  }
>>  
>> -static void
>> +static int
>>  parse_caps(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  {
>>  	struct hfi_capabilities *caps = data;
>> @@ -134,12 +138,14 @@ parse_caps(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  	struct hfi_capability caps_arr[MAX_CAP_ENTRIES] = {};
>>  
>>  	if (num_caps > MAX_CAP_ENTRIES)
>> -		return;
>> +		return -EINVAL;
>>  
>>  	memcpy(caps_arr, cap, num_caps * sizeof(*cap));
>>  
>>  	for_each_codec(core->caps, ARRAY_SIZE(core->caps), codecs, domain,
>>  		       fill_caps, caps_arr, num_caps);
>> +
>> +	return sizeof(*caps);
>>  }
>>  
>>  static void fill_raw_fmts(struct hfi_plat_caps *cap, const void *fmts,
>> @@ -154,7 +160,7 @@ static void fill_raw_fmts(struct hfi_plat_caps *cap, const void *fmts,
>>  	cap->num_fmts += num_fmts;
>>  }
>>  
>> -static void
>> +static int
>>  parse_raw_formats(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  {
>>  	struct hfi_uncompressed_format_supported *fmt = data;
>> @@ -163,7 +169,8 @@ parse_raw_formats(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  	struct raw_formats rawfmts[MAX_FMT_ENTRIES] = {};
>>  	u32 entries = fmt->format_entries;
>>  	unsigned int i = 0;
>> -	u32 num_planes;
>> +	u32 num_planes = 0;
>> +	u32 size;
>>  
>>  	while (entries) {
>>  		num_planes = pinfo->num_planes;
>> @@ -173,7 +180,7 @@ parse_raw_formats(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  		i++;
>>  
>>  		if (i >= MAX_FMT_ENTRIES)
>> -			return;
>> +			return -EINVAL;
>>  
>>  		if (pinfo->num_planes > MAX_PLANES)
>>  			break;
>> @@ -185,9 +192,13 @@ parse_raw_formats(struct venus_core *core, u32 codecs, u32 domain, void *data)
>>  
>>  	for_each_codec(core->caps, ARRAY_SIZE(core->caps), codecs, domain,
>>  		       fill_raw_fmts, rawfmts, i);
>> +	size = fmt->format_entries * (sizeof(*constr) * num_planes + 2 * sizeof(u32))
>> +		+ 2 * sizeof(u32);
>> +
>> +	return size;
>>  }
>>  
>> -static void parse_codecs(struct venus_core *core, void *data)
>> +static int parse_codecs(struct venus_core *core, void *data)
>>  {
>>  	struct hfi_codec_supported *codecs = data;
>>  
>> @@ -199,21 +210,27 @@ static void parse_codecs(struct venus_core *core, void *data)
>>  		core->dec_codecs &= ~HFI_VIDEO_CODEC_SPARK;
>>  		core->enc_codecs &= ~HFI_VIDEO_CODEC_HEVC;
>>  	}
>> +
>> +	return sizeof(*codecs);
>>  }
>>  
>> -static void parse_max_sessions(struct venus_core *core, const void *data)
>> +static int parse_max_sessions(struct venus_core *core, const void *data)
>>  {
>>  	const struct hfi_max_sessions_supported *sessions = data;
>>  
>>  	core->max_sessions_supported = sessions->max_sessions;
>> +
>> +	return sizeof(*sessions);
>>  }
>>  
>> -static void parse_codecs_mask(u32 *codecs, u32 *domain, void *data)
>> +static int parse_codecs_mask(u32 *codecs, u32 *domain, void *data)
>>  {
>>  	struct hfi_codec_mask_supported *mask = data;
>>  
>>  	*codecs = mask->codecs;
>>  	*domain = mask->video_domains;
>> +
>> +	return sizeof(*mask);
>>  }
>>  
>>  static void parser_init(struct venus_inst *inst, u32 *codecs, u32 *domain)
>> @@ -282,8 +299,9 @@ static int hfi_platform_parser(struct venus_core *core, struct venus_inst *inst)
>>  u32 hfi_parser(struct venus_core *core, struct venus_inst *inst, void *buf,
>>  	       u32 size)
>>  {
>> -	unsigned int words_count = size >> 2;
>> -	u32 *word = buf, *data, codecs = 0, domain = 0;
>> +	u32 *words = buf, *payload, codecs = 0, domain = 0;
>> +	u32 *frame_size = buf + size;
>> +	u32 rem_bytes = size;
>>  	int ret;
>>  
>>  	ret = hfi_platform_parser(core, inst);
>> @@ -300,38 +318,63 @@ u32 hfi_parser(struct venus_core *core, struct venus_inst *inst, void *buf,
>>  		memset(core->caps, 0, sizeof(core->caps));
>>  	}
>>  
>> -	while (words_count) {
>> -		data = word + 1;
>> +	while (words < frame_size) {
>> +		payload = words + 1;
>>  
>> -		switch (*word) {
>> +		switch (*words) {
>>  		case HFI_PROPERTY_PARAM_CODEC_SUPPORTED:
>> -			parse_codecs(core, data);
>> +			if (rem_bytes <= sizeof(struct hfi_codec_supported))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_codecs(core, payload);
>>  			init_codecs(core);
> 
> Does it make sense to call init_codecs if parse_codecs returned an error?
> It certainly looks weird, so even if it is OK, perhaps a comment might be
> useful.
parse_codecs() returns the sizeof(struct hfi_codec_supported), so it would
always be a valid value. I can put up a comment though.
> 
>>  			break;
>>  		case HFI_PROPERTY_PARAM_MAX_SESSIONS_SUPPORTED:
>> -			parse_max_sessions(core, data);
>> +			if (rem_bytes <= sizeof(struct hfi_max_sessions_supported))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_max_sessions(core, payload);
>>  			break;
>>  		case HFI_PROPERTY_PARAM_CODEC_MASK_SUPPORTED:
>> -			parse_codecs_mask(&codecs, &domain, data);
>> +			if (rem_bytes <= sizeof(struct hfi_codec_mask_supported))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_codecs_mask(&codecs, &domain, payload);
>>  			break;
>>  		case HFI_PROPERTY_PARAM_UNCOMPRESSED_FORMAT_SUPPORTED:
>> -			parse_raw_formats(core, codecs, domain, data);
>> +			if (rem_bytes <= sizeof(struct hfi_uncompressed_format_supported))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_raw_formats(core, codecs, domain, payload);
>>  			break;
>>  		case HFI_PROPERTY_PARAM_CAPABILITY_SUPPORTED:
>> -			parse_caps(core, codecs, domain, data);
>> +			if (rem_bytes <= sizeof(struct hfi_capabilities))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_caps(core, codecs, domain, payload);
>>  			break;
>>  		case HFI_PROPERTY_PARAM_PROFILE_LEVEL_SUPPORTED:
>> -			parse_profile_level(core, codecs, domain, data);
>> +			if (rem_bytes <= sizeof(struct hfi_profile_level_supported))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_profile_level(core, codecs, domain, payload);
>>  			break;
>>  		case HFI_PROPERTY_PARAM_BUFFER_ALLOC_MODE_SUPPORTED:
>> -			parse_alloc_mode(core, codecs, domain, data);
>> +			if (rem_bytes <= sizeof(struct hfi_buffer_alloc_mode_supported))
>> +				return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +			ret = parse_alloc_mode(core, codecs, domain, payload);
>>  			break;
>>  		default:
>> +			ret = sizeof(u32);
>>  			break;
>>  		}
>>  
>> -		word++;
>> -		words_count--;
>> +		if (ret < 0)
>> +			return HFI_ERR_SYS_INSUFFICIENT_RESOURCES;
>> +
>> +		words += ret / sizeof(u32);
> 
> Would it make sense to check and warn if ret is not a multiple of sizeof(u32)?
> Up to you, just an idea.
almost all the individual parsing api in the various cases returns size of
predefined structures (or in their multiples), which would make them return in
multiple of sizeof(u32). Let say, if it encounters a non multiple of
sizeof(u32), the while loop would iterate couple of more iterations to hit the
next case in the payload.
> 
>> +		rem_bytes -= ret;
>>  	}
>>  
>>  	if (!core->max_sessions_supported)
>>
> 
> Regards,
> 
> 	Hans
Regards,
Vikash