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Groups > linux.kernel > #1694392
| From | Ding Tianhong <dingtianhong@huawei.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: af_packet: use after free in prb_retire_rx_blk_timer_expired |
| Date | 2017-07-24 03:40 +0200 |
| Message-ID | <u6AvL-6Bf-5@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <u6g41-2gT-1@gated-at.bofh.it> <u6i5Q-3vn-3@gated-at.bofh.it> <u6oNX-7Vt-9@gated-at.bofh.it> <u6sye-1RK-19@gated-at.bofh.it> <u6Acp-6uG-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 2017/7/24 9:09, Ding Tianhong wrote:
>
>
> On 2017/7/24 1:03, Cong Wang wrote:
>> On Sun, Jul 23, 2017 at 5:48 AM, liujian (CE) <liujian56@huawei.com> wrote:
>>> Hi
>>>
>>> I find it caused by below steps:
>>> 1. set tp_version to TPACKET_V3 and req->tp_block_nr to 1
>>> 2. set tp_block_nr to 0
>>> Then pg_vec was freed, and we did not delete the timer?
>>
>> Thanks for testing!
>>
>> Ah, I overlook the initialization case in my previous patch.
>>
>> How about the following one? Does it cover all the cases?
>>
>>
>> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
>> index 008bb34ee324..0615c2a950fa 100644
>> --- a/net/packet/af_packet.c
>> +++ b/net/packet/af_packet.c
>> @@ -4329,7 +4329,7 @@ static int packet_set_ring(struct sock *sk,
>> union tpacket_req_u *req_u,
>> register_prot_hook(sk);
>> }
>> spin_unlock(&po->bind_lock);
>> - if (closing && (po->tp_version > TPACKET_V2)) {
>> + if (pg_vec && (po->tp_version > TPACKET_V2)) {
>> /* Because we don't support block-based V3 on tx-ring */
>> if (!tx_ring)
>> prb_shutdown_retire_blk_timer(po, rb_queue);
>>
>> .
>
> Hi, Cong:
>
> It looks like could not cover the case: req->tp_block_nr = 2 -> reg->tp_block_nr = 1 .
>
Oh, looks like this case would never happen, so I think your solution is ok.
> what about this way:
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -4331,13 +4331,17 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
> register_prot_hook(sk);
> }
> spin_unlock(&po->bind_lock);
> - if (closing && (po->tp_version > TPACKET_V2)) {
> + if ((closing || (pg_vec && !reg->tp_block_nr))&& (po->tp_version > TPACKET_V2)) {
> /* Because we don't support block-based V3 on tx-ring */
> if (!tx_ring)
> prb_shutdown_retire_blk_timer(po, rb_queue);
>
>
>>
>
>
> .
>
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RE: af_packet: use after free in prb_retire_rx_blk_timer_expired "liujian (CE)" <liujian56@huawei.com> - 2017-07-22 12:10 +0200
Re: af_packet: use after free in prb_retire_rx_blk_timer_expired Cong Wang <xiyou.wangcong@gmail.com> - 2017-07-22 21:10 +0200
Re: af_packet: use after free in prb_retire_rx_blk_timer_expired Ding Tianhong <dingtianhong@huawei.com> - 2017-07-23 05:50 +0200
Re: af_packet: use after free in prb_retire_rx_blk_timer_expired Cong Wang <xiyou.wangcong@gmail.com> - 2017-07-23 08:00 +0200
RE: af_packet: use after free in prb_retire_rx_blk_timer_expired "liujian (CE)" <liujian56@huawei.com> - 2017-07-23 10:30 +0200
RE: af_packet: use after free in prb_retire_rx_blk_timer_expired "liujian (CE)" <liujian56@huawei.com> - 2017-07-23 12:00 +0200
RE: af_packet: use after free in prb_retire_rx_blk_timer_expired "liujian (CE)" <liujian56@huawei.com> - 2017-07-23 15:10 +0200
Re: af_packet: use after free in prb_retire_rx_blk_timer_expired Cong Wang <xiyou.wangcong@gmail.com> - 2017-07-23 19:10 +0200
Re: af_packet: use after free in prb_retire_rx_blk_timer_expired Ding Tianhong <dingtianhong@huawei.com> - 2017-07-24 03:20 +0200
Re: af_packet: use after free in prb_retire_rx_blk_timer_expired Ding Tianhong <dingtianhong@huawei.com> - 2017-07-24 03:40 +0200
RE: af_packet: use after free in prb_retire_rx_blk_timer_expired "liujian (CE)" <liujian56@huawei.com> - 2017-07-24 12:50 +0200
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