[PATCH E/D/B 3/3] UBUNTU: SAUCE: mwifiex: Fix heap overflow in mmwifiex_process_tdls_action_frame()

[Stefan Bader]

On 27.11.19 17:21, Kleber Souza wrote:
> On 26.11.19 09:39, Stefan Bader wrote:
>> From: qize wang <wangqize888888888 at gmail.com>
>>
>> mwifiex_process_tdls_action_frame() without checking
>> the incoming tdls infomation element's vality before use it,
>> this may cause multi heap buffer overflows.
>>
>> Fix them by putting vality check before use it.
>>
>> Signed-off-by: qize wang <wangqize888888888 at gmail.com>
>>
>> CVE-2019-14901
>>
>> (cherry picked from https://patchwork.kernel.org/patch/11257535/)
>> Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
>> ---
>>  drivers/net/wireless/marvell/mwifiex/tdls.c | 70 +++++++++++++++++++--
>>  1 file changed, 64 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/wireless/marvell/mwifiex/tdls.c b/drivers/net/wireless/marvell/mwifiex/tdls.c
>> index 18e654dc34c6..7f60214852c0 100644
>> --- a/drivers/net/wireless/marvell/mwifiex/tdls.c
>> +++ b/drivers/net/wireless/marvell/mwifiex/tdls.c
>> @@ -954,59 +954,117 @@ void mwifiex_process_tdls_action_frame(struct mwifiex_private *priv,
>>  
>>  		switch (*pos) {
>>  		case WLAN_EID_SUPP_RATES:
>> +			if (pos[1] > 32)
>> +				return;
>>  			sta_ptr->tdls_cap.rates_len = pos[1];
>>  			for (i = 0; i < pos[1]; i++)
>>  				sta_ptr->tdls_cap.rates[i] = pos[i + 2];
>>  			break;
>>  
>>  		case WLAN_EID_EXT_SUPP_RATES:
>> +			if (pos[1] > 32)
>> +				return;
>>  			basic = sta_ptr->tdls_cap.rates_len;
>> +			if (pos[1] > 32 - basic)
>> +				return;
>>  			for (i = 0; i < pos[1]; i++)
>>  				sta_ptr->tdls_cap.rates[basic + i] = pos[i + 2];
>>  			sta_ptr->tdls_cap.rates_len += pos[1];
>>  			break;
>>  		case WLAN_EID_HT_CAPABILITY:
>> -			memcpy((u8 *)&sta_ptr->tdls_cap.ht_capb, pos,
>> +			if (pos > end - sizeof(struct ieee80211_ht_cap) - 2)
>> +				return;
>> +			if (pos[1] != sizeof(struct ieee80211_ht_cap))
>> +				return;
>> +			/* copy the ie's value into ht_capb*/
>> +			memcpy((u8 *)&sta_ptr->tdls_cap.ht_capb, pos + 2,
> 
> This is changing the memcpy to start the copy from 'pos' to 'pos + 2',
> but following the discussion on the patchwork link it seems the original
> code was wrong and it was fixed here but without a comment on the commit
> message. So if accepted upstream the commit message might get changed.

What I understood from the upstream discussion there is two different targets of
memcpy's. Some are of type header which still need the additional 2 bytes. The
others are of a different type which does not contain the header part.

> 
>>  			       sizeof(struct ieee80211_ht_cap));
>>  			sta_ptr->is_11n_enabled = 1;
>>  			break;
>>  		case WLAN_EID_HT_OPERATION:
>> -			memcpy(&sta_ptr->tdls_cap.ht_oper, pos,
>> +			if (pos > end -
>> +			    sizeof(struct ieee80211_ht_operation) - 2)
>> +				return;
>> +			if (pos[1] != sizeof(struct ieee80211_ht_operation))
>> +				return;
>> +			/* copy the ie's value into ht_oper*/
>> +			memcpy(&sta_ptr->tdls_cap.ht_oper, pos + 2,
>>  			       sizeof(struct ieee80211_ht_operation));
>>  			break;
>>  		case WLAN_EID_BSS_COEX_2040:
>> +			if (pos > end - 3)
>> +				return;
>> +			if (pos[1] != 1)
>> +				return;
>>  			sta_ptr->tdls_cap.coex_2040 = pos[2];
>>  			break;
>>  		case WLAN_EID_EXT_CAPABILITY:
>> +			if (pos > end - sizeof(struct ieee_types_header))
>> +				return;
>> +			if (pos[1] < sizeof(struct ieee_types_header))
>> +				return;
>> +			if (pos[1] > 8)
>> +				return;
>>  			memcpy((u8 *)&sta_ptr->tdls_cap.extcap, pos,
>>  			       sizeof(struct ieee_types_header) +
>>  			       min_t(u8, pos[1], 8));
>>  			break;
>>  		case WLAN_EID_RSN:
>> +			if (pos > end - sizeof(struct ieee_types_header))
>> +				return;
>> +			if (pos[1] < sizeof(struct ieee_types_header))
>> +				return;
>> +			if (pos[1] > IEEE_MAX_IE_SIZE -
>> +			    sizeof(struct ieee_types_header))
>> +				return;
>>  			memcpy((u8 *)&sta_ptr->tdls_cap.rsn_ie, pos,
>>  			       sizeof(struct ieee_types_header) +
>>  			       min_t(u8, pos[1], IEEE_MAX_IE_SIZE -
>>  				     sizeof(struct ieee_types_header)));
>>  			break;
>>  		case WLAN_EID_QOS_CAPA:
>> +			if (pos > end - 3)
>> +				return;
>> +			if (pos[1] != 1)
>> +				return;
>>  			sta_ptr->tdls_cap.qos_info = pos[2];
>>  			break;
>>  		case WLAN_EID_VHT_OPERATION:
>> -			if (priv->adapter->is_hw_11ac_capable)
>> -				memcpy(&sta_ptr->tdls_cap.vhtoper, pos,
>> +			if (priv->adapter->is_hw_11ac_capable) {
>> +				if (pos > end -
>> +				    sizeof(struct ieee80211_vht_operation) - 2)
>> +					return;
>> +				if (pos[1] !=
>> +				    sizeof(struct ieee80211_vht_operation))
>> +					return;
>> +				/* copy the ie's value into vhtoper*/
>> +				memcpy(&sta_ptr->tdls_cap.vhtoper, pos + 2,
>>  				       sizeof(struct ieee80211_vht_operation));
>> +			}
>>  			break;
>>  		case WLAN_EID_VHT_CAPABILITY:
>>  			if (priv->adapter->is_hw_11ac_capable) {
>> -				memcpy((u8 *)&sta_ptr->tdls_cap.vhtcap, pos,
>> +				if (pos > end -
>> +				    sizeof(struct ieee80211_vht_cap) - 2)
>> +					return;
>> +				if (pos[1] != sizeof(struct ieee80211_vht_cap))
>> +					return;
>> +				/* copy the ie's value into vhtcap*/
>> +				memcpy((u8 *)&sta_ptr->tdls_cap.vhtcap, pos + 2,
>>  				       sizeof(struct ieee80211_vht_cap));
>>  				sta_ptr->is_11ac_enabled = 1;
>>  			}
>>  			break;
>>  		case WLAN_EID_AID:
>> -			if (priv->adapter->is_hw_11ac_capable)
>> +			if (priv->adapter->is_hw_11ac_capable) {
>> +				if (pos > end - 4)
>> +					return;
>> +				if (pos[1] != 2)
>> +					return;
>>  				sta_ptr->tdls_cap.aid =
>>  					get_unaligned_le16((pos + 2));
>> +			}
>> +			break;
>>  		default:
>>  			break;
>>  		}
>>
> 


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