Re: [PATCH v2 net-next] fix unsafe set_memory_rw from softirq

[Alexei Starovoitov]

On Thu, Oct 3, 2013 at 4:07 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> On Thu, 2013-10-03 at 15:47 -0700, Alexei Starovoitov wrote:
>
>> @@ -722,7 +725,8 @@ EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy);
>>  int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
>>  {
>>       struct sk_filter *fp, *old_fp;
>> -     unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
>> +     unsigned int fsize = max(sizeof(struct sock_filter) * fprog->len,
>> +                              sizeof(struct work_struct));
>>       int err;
>>
>>       if (sock_flag(sk, SOCK_FILTER_LOCKED))
>
> Thats broken, as we might copy more data from user than expected,
> and eventually trigger EFAULT :
>
> if (copy_from_user(fp->insns, fprog->filter, fsize)) {

yes. will fix.
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