Re: [RFCv2 bluetooth-next 14/16] ieee802154: 6lowpan: check on valid 802.15.4 frame

[Stefan Schmidt <stefan@osg.samsung.com>]

Hello.

On 31/08/15 00:03, Stefan Schmidt wrote:
> Hello.
>
> On 20/08/15 18:47, Alexander Aring wrote:
>> This patch adds frame control checks to check if the received frame is
>> something which could contain a 6LoWPAN packet.
>>
>> Signed-off-by: Alexander Aring <alex.aring@gmail.com>
>> ---
>>   include/linux/ieee802154.h  | 25 +++++++++++++++++++++++++
>>   include/net/mac802154.h     | 15 +++++++++++++++
>>   net/ieee802154/6lowpan/rx.c |  8 ++++++++
>>   3 files changed, 48 insertions(+)
>>
>> diff --git a/include/linux/ieee802154.h b/include/linux/ieee802154.h
>> index 1dc1f4e..db01492 100644
>> --- a/include/linux/ieee802154.h
>> +++ b/include/linux/ieee802154.h
>> @@ -205,6 +205,31 @@ enum {
>>       IEEE802154_SCAN_IN_PROGRESS = 0xfc,
>>   };
>>   +/* frame control handling */
>> +#define IEEE802154_FCTL_FTYPE        0x0003
>> +#define IEEE802154_FCTL_INTRA_PAN    0x0040
>> +
>> +#define IEEE802154_FTYPE_DATA        0x0001
>> +
>> +/*
>> + * ieee802154_is_data - check if type is IEEE802154_FTYPE_DATA
>> + * @fc: frame control bytes in little-endian byteorder
>> + */
>> +static inline int ieee802154_is_data(__le16 fc)
>> +{
>> +    return (fc & cpu_to_le16(IEEE802154_FCTL_FTYPE)) ==
>> +        cpu_to_le16(IEEE802154_FTYPE_DATA);
>> +}
>> +
>> +/**
>> + * ieee802154_is_intra_pan - check if intra pan id communication
>> + * @fc: frame control bytes in little-endian byteorder
>> + */
>> +static inline bool ieee802154_is_intra_pan(__le16 fc)
>> +{
>> +    return fc & cpu_to_le16(IEEE802154_FCTL_INTRA_PAN);
>> +}
>> +
>>   /**
>>    * ieee802154_is_valid_psdu_len - check if psdu len is valid
>>    * available lengths:
>> diff --git a/include/net/mac802154.h b/include/net/mac802154.h
>> index b7f9961..32bd7c0 100644
>> --- a/include/net/mac802154.h
>> +++ b/include/net/mac802154.h
>> @@ -250,6 +250,21 @@ struct ieee802154_ops {
>>   };
>>     /**
>> + * ieee802154_get_fc_from_skb - get the frame control field from an skb
>> + * @skb: skb where the frame control field will be get from
>> + */
>> +static inline __le16 ieee802154_get_fc_from_skb(const struct sk_buff 
>> *skb)
>> +{
>> +    /* return some invalid fc on failure */
>> +    if (unlikely(skb->mac_len < 2)) {
>> +        WARN_ON(1);
>> +        return cpu_to_le16(0);
>> +    }
>> +
>> +    return (__force 
>> __le16)__get_unaligned_memmove16(skb_mac_header(skb));
>> +}
>> +
>> +/**
>>    * ieee802154_be64_to_le64 - copies and convert be64 to le64
>>    * @le64_dst: le64 destination pointer
>>    * @be64_src: be64 source pointer
>> diff --git a/net/ieee802154/6lowpan/rx.c b/net/ieee802154/6lowpan/rx.c
>> index f98ebf5..5be996a 100644
>> --- a/net/ieee802154/6lowpan/rx.c
>> +++ b/net/ieee802154/6lowpan/rx.c
>> @@ -11,6 +11,7 @@
>>   #include <linux/if_arp.h>
>>     #include <net/6lowpan.h>
>> +#include <net/mac802154.h>
>>   #include <net/ieee802154_netdev.h>
>>     #include "6lowpan_i.h"
>> @@ -278,6 +279,13 @@ static inline bool lowpan_is_reserved(u8 dispatch)
>>    */
>>   static inline bool lowpan_rx_h_check(struct sk_buff *skb)
>>   {
>> +    __le16 fc = ieee802154_get_fc_from_skb(skb);
>> +
>> +    /* check on ieee802154 conform 6LoWPAN header */
>> +    if (!ieee802154_is_data(fc) ||
>> +        !ieee802154_is_intra_pan(fc))
>> +        return false;
>> +
>>       /* check if we can dereference the dispatch */
>>       if (unlikely(!skb->len))
>>           return false;
>
> Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>
>

This should also have been

Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>

regards
Stefan Schmidt