Re: [iwl-net v2 5/5] ice: fix using untrusted value of pkt_len in ice_vc_fdir_parse_raw()

["Szapar-Mudlaw, Martyna" <martyna.szapar-mudlaw@linux.intel.com>]

On 2/28/2025 6:09 PM, Simon Horman wrote:
> On Tue, Feb 25, 2025 at 10:08:49AM +0100, Martyna Szapar-Mudlaw wrote:
>> From: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
>>
>> Fix using the untrusted value of proto->raw.pkt_len in function
>> ice_vc_fdir_parse_raw() by verifying if it does not exceed the
>> VIRTCHNL_MAX_SIZE_RAW_PACKET value.
>>
>> Fixes: 99f419df8a5c ("ice: enable FDIR filters from raw binary patterns for VFs")
>> Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
>> Signed-off-by: Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>
>> ---
>>   .../ethernet/intel/ice/ice_virtchnl_fdir.c    | 25 +++++++++++++------
>>   1 file changed, 17 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ice/ice_virtchnl_fdir.c b/drivers/net/ethernet/intel/ice/ice_virtchnl_fdir.c
>> index 14e3f0f89c78..6250629ee8f9 100644
>> --- a/drivers/net/ethernet/intel/ice/ice_virtchnl_fdir.c
>> +++ b/drivers/net/ethernet/intel/ice/ice_virtchnl_fdir.c
>> @@ -835,18 +835,27 @@ ice_vc_fdir_parse_raw(struct ice_vf *vf,
>>   	u8 *pkt_buf, *msk_buf __free(kfree);
>>   	struct ice_parser_result rslt;
>>   	struct ice_pf *pf = vf->pf;
>> +	u16 pkt_len, udp_port = 0;
>>   	struct ice_parser *psr;
>>   	int status = -ENOMEM;
>>   	struct ice_hw *hw;
>> -	u16 udp_port = 0;
>>   
>> -	pkt_buf = kzalloc(proto->raw.pkt_len, GFP_KERNEL);
>> -	msk_buf = kzalloc(proto->raw.pkt_len, GFP_KERNEL);
>> +	if (!proto->raw.pkt_len)
>> +		return -EINVAL;
>> +
>> +	pkt_len = proto->raw.pkt_len;
> 
> Hi Martyna,
> 
> A check is made for !proto->raw.pkt_len above.
> And a check is made for !pkt_len below.
> 
> This seems redundant.

Right, thank you for spotting it, will fix

> 
>> +
>> +	if (!pkt_len || pkt_len > VIRTCHNL_MAX_SIZE_RAW_PACKET)
>> +		return -EINVAL;
> 
> ...