On 2023/08/09 6:53, Kees Cook wrote:
>
> [...]
>>>
>>> diff --git a/include/uapi/linux/netfilter_bridge/ebtables.h b/include/uapi/linux/netfilter_bridge/ebtables.h
>>> index a494cf43a755..b0caad82b693 100644
>>> --- a/include/uapi/linux/netfilter_bridge/ebtables.h
>>> +++ b/include/uapi/linux/netfilter_bridge/ebtables.h
>>> @@ -182,12 +182,14 @@ struct ebt_entry {
>>> unsigned char sourcemsk[ETH_ALEN];
>>> unsigned char destmac[ETH_ALEN];
>>> unsigned char destmsk[ETH_ALEN];
>>> - /* sizeof ebt_entry + matches */
>>> - unsigned int watchers_offset;
>>> - /* sizeof ebt_entry + matches + watchers */
>>> - unsigned int target_offset;
>>> - /* sizeof ebt_entry + matches + watchers + target */
>>> - unsigned int next_offset;
>>> + __struct_group(/* no tag */, offsets, /* no attrs */,
>>> + /* sizeof ebt_entry + matches */
>>> + unsigned int watchers_offset;
>>> + /* sizeof ebt_entry + matches + watchers */
>>> + unsigned int target_offset;
>>> + /* sizeof ebt_entry + matches + watchers + target */
>>> + unsigned int next_offset;
>>> + );
>>> unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
>
> While we're here, can we drop this [0] in favor of []?
>
> -Kees
>
Look like it could be done. Will do in v3. Thanks!
>>> };
>>>
>>> diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
>>> index 757ec46fc45a..5ec66b1ebb64 100644
>>> --- a/net/bridge/netfilter/ebtables.c
>>> +++ b/net/bridge/netfilter/ebtables.c
>>> @@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
>>> return ret;
>>>
>>> offsets[0] = sizeof(struct ebt_entry); /* matches come first */
>>> - memcpy(&offsets[1], &entry->watchers_offset,
>>> - sizeof(offsets) - sizeof(offsets[0]));
>>> + memcpy(&offsets[1], &entry->offsets, sizeof(offsets) - sizeof(offsets[0]));
>> ^^^^^^^^^^^^
>> You now can replace this ____________________________________|
>> with just `sizeof(entry->offsets)`
>>
>> With that change you can add my
>> Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
>>
>> Thank you
>> --
>> Gustavo
>>
>>>
>>> if (state->buf_kern_start) {
>>> buf_start = state->buf_kern_start + state->buf_kern_offset;
>>> --
>>> 2.41.0
>>>
>
>
