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Message-ID: <7bb7522a2bda40b8b4a9aac54ea1098b@huawei.com>
Date: Fri, 24 Jul 2020 03:35:02 +0000
From: "Guodeqing (A)" <geffrey.guo@...wei.com>
To: Eric Dumazet <edumazet@...gle.com>
CC: David Miller <davem@...emloft.net>,
"kuba@...nel.org" <kuba@...nel.org>,
"maheshb@...gle.com" <maheshb@...gle.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: 答复: [PATCH,v2] ipvlan: add the check of ip header checksum
The ihl check maybe not suitable in ip_fast_csum, the correct of the ihl value can be checked before calling the ip_fast_csum.
The implementation of ip_fast_csum is different in different cpu architecture. the IP packet will do ip forward in the ipvlan l3/l3s mode and the corrupted ip packet
should be discarded as soon as possible. Thanks.
-----邮件原件-----
发件人: Eric Dumazet [mailto:edumazet@...gle.com]
发送时间: Thursday, July 23, 2020 10:15
收件人: Guodeqing (A) <geffrey.guo@...wei.com>
抄送: David Miller <davem@...emloft.net>; kuba@...nel.org; maheshb@...gle.com; netdev@...r.kernel.org
主题: Re: [PATCH,v2] ipvlan: add the check of ip header checksum
On Wed, Jul 22, 2020 at 6:59 PM Guodeqing (A) <geffrey.guo@...wei.com> wrote:
>
> I am sorry, the mail is not sent to you directly;
>
> If do the following test,this will cause a panic in a arm64 VM. this can be reproduced easily.
>
> Linux osc 5.8.0-rc6+ #3 SMP Thu Jul 23 01:40:47 UTC 2020 aarch64
>
> The programs included with the Debian GNU/Linux system are free
> software; the exact distribution terms for each program are described
> in the individual files in /usr/share/doc/*/copyright.
>
> Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
> permitted by applicable law.
> root@osc:~# ifconfig eth0 up
> root@osc:~# ip netns add ns1
> root@osc:~# ip link add gw link eth0 type ipvlan root@osc:~# ip addr
> add 168.16.0.1/24 dev gw root@osc:~# ip link set dev gw up root@osc:~#
> ip link add ip1 link eth0 type ipvlan root@osc:~# ip link set ip1
> netns ns1 root@osc:~# ip netns exec ns1 ip link set ip1 up root@osc:~#
> ip netns exec ns1 ip addr add 168.16.0.2/24 dev ip1 root@osc:~# ip
> netns exec ns1 ip link set lo up root@osc:~# ip netns exec ns1 ip addr
> add 127.0.0.1/8 dev lo RTNETLINK answers: File exists root@osc:~# ip
> netns exec ns1 tc qdisc add dev ip1 root netem corrupt 100%
> root@osc:~# ip netns exec ns1 ping 168.16.0.1 PING 168.16.0.1
> (168.16.0.1) 56(84) bytes of data.
> From 168.16.0.1 icmp_seq=2 Destination Host Unreachable From
> 168.16.0.1 icmp_seq=12 Destination Host Unreachable From 168.16.0.1
> icmp_seq=30 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=48 ttl=64 time=0.052 ms
> 64 bytes from 168.16.0.1: icmp_seq=65 ttl=64 time=0.060 ms From
> 168.16.0.1 icmp_seq=80 Destination Host Unreachable From 168.16.0.1
> icmp_seq=97 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=100 ttl=64 time=0.022 ms
> 64 bytes from 168.16.0.1: icmp_seq=101 ttl=64 time=0.054 ms
> 64 bytes from 168.16.0.1: icmp_seq=103 ttl=64 time=0.053 ms From
> 168.16.0.1 icmp_seq=102 Destination Host Unreachable From 168.16.0.1
> icmp_seq=127 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=132 ttl=64 time=0.057 ms
> 64 bytes from 168.16.0.1: icmp_seq=135 ttl=64 time=0.051 ms
> 64 bytes from 168.16.0.1: icmp_seq=141 ttl=64 time=0.051 ms From
> 168.16.0.1 icmp_seq=140 Destination Host Unreachable From 168.16.0.1
> icmp_seq=142 Destination Host Unreachable From 168.16.0.1 icmp_seq=150
> Destination Host Unreachable From 168.16.0.1 icmp_seq=154 Destination
> Host Unreachable From 168.16.0.1 icmp_seq=164 Destination Host
> Unreachable From 168.16.0.1 icmp_seq=169 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=173 ttl=64 time=0.056 ms
> 64 bytes from 168.16.0.1: icmp_seq=185 ttl=64 time=0.058 ms
> 64 bytes from 168.16.0.1: icmp_seq=202 ttl=64 time=0.056 ms
> 64 bytes from 168.16.0.1: icmp_seq=203 ttl=64 time=0.057 ms
> 64 bytes from 168.16.0.1: icmp_seq=219 ttl=64 time=0.050 ms
> 64 bytes from 168.16.0.1: icmp_seq=227 ttl=64 time=0.057 ms
> 64 bytes from 168.16.0.1: icmp_seq=228 ttl=64 time=0.044 ms From
> 168.16.0.1 icmp_seq=237 Destination Host Unreachable From 168.16.0.1
> icmp_seq=239 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=243 ttl=64 time=0.053 ms From
> 168.16.0.1 icmp_seq=242 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=246 ttl=64 time=0.056 ms
> 64 bytes from 168.16.0.1: icmp_seq=254 ttl=64 time=0.056 ms
> 64 bytes from 168.16.0.1: icmp_seq=255 ttl=64 time=0.054 ms From
> 168.16.0.1 icmp_seq=263 Destination Host Unreachable From 168.16.0.1
> icmp_seq=269 Destination Host Unreachable From 168.16.0.1 icmp_seq=273
> Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=279 ttl=64 time=0.057 ms From
> 168.16.0.1 icmp_seq=284 Destination Host Unreachable From 168.16.0.1
> icmp_seq=286 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=291 ttl=64 time=0.054 ms
> 64 bytes from 168.16.0.1: icmp_seq=293 ttl=64 time=0.058 ms From
> 168.16.0.1 icmp_seq=294 Destination Host Unreachable From 168.16.0.1
> icmp_seq=298 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=309 ttl=64 time=0.056 ms From
> 168.16.0.1 icmp_seq=310 Destination Host Unreachable From 168.16.0.1
> icmp_seq=312 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=332 ttl=64 time=0.055 ms From
> 168.16.0.1 icmp_seq=334 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=340 ttl=64 time=0.055 ms
> 64 bytes from 168.16.0.1: icmp_seq=344 ttl=64 time=0.050 ms
> 64 bytes from 168.16.0.1: icmp_seq=355 ttl=64 time=0.057 ms
> 64 bytes from 168.16.0.1: icmp_seq=358 ttl=64 time=0.050 ms From
> 168.16.0.1 icmp_seq=356 Destination Host Unreachable From 168.16.0.1
> icmp_seq=369 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=382 ttl=64 time=0.053 ms From
> 168.16.0.1 icmp_seq=381 Destination Host Unreachable From 168.16.0.1
> icmp_seq=396 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=400 ttl=64 time=0.058 ms From
> 168.16.0.1 icmp_seq=406 Destination Host Unreachable From 168.16.0.1
> icmp_seq=414 Destination Host Unreachable From 168.16.0.1 icmp_seq=417
> Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=422 ttl=64 time=0.018 ms
> 64 bytes from 168.16.0.1: icmp_seq=423 ttl=64 time=0.058 ms
> 64 bytes from 168.16.0.1: icmp_seq=429 ttl=64 time=0.056 ms
> 64 bytes from 168.16.0.1: icmp_seq=445 ttl=64 time=0.049 ms From
> 168.16.0.1 icmp_seq=444 Destination Host Unreachable From 168.16.0.1
> icmp_seq=453 Destination Host Unreachable From 168.16.0.1 icmp_seq=455
> Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=456 ttl=64 time=0.024 ms
> 64 bytes from 168.16.0.1: icmp_seq=469 ttl=64 time=0.058 ms From
> 168.16.0.1 icmp_seq=475 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=483 ttl=64 time=0.054 ms From
> 168.16.0.1 icmp_seq=488 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=504 ttl=64 time=0.056 ms
> 64 bytes from 168.16.0.1: icmp_seq=505 ttl=64 time=0.055 ms From
> 168.16.0.1 icmp_seq=510 Destination Host Unreachable From 168.16.0.1
> icmp_seq=511 Destination Host Unreachable
> 64 bytes from 168.16.0.1: icmp_seq=516 ttl=64 time=0.055 ms From
> 168.16.0.1 icmp_seq=519 Destination Host Unreachable [ 582.368938]
> Unable to handle kernel paging request at virtual address
> ffff0000f85f0000 [ 582.369732] Mem abort info:
> [ 582.369987] ESR = 0x96000007
> [ 582.370266] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 582.370833] SET = 0, FnV = 0
> [ 582.371113] EA = 0, S1PTW = 0
> [ 582.371391] Data abort info:
> [ 582.371671] ISV = 0, ISS = 0x00000007
> [ 582.372017] CM = 0, WnR = 0
> [ 582.372299] swapper pgtable: 4k pages, 48-bit VAs,
> pgdp=000000012dab7000 [ 582.372896] [ffff0000f85f0000]
> pgd=000000013fff8003, p4d=000000013fff8003, pud=000000013f9f4003,
> pmd=000000013f838003, pte=0000000000000000 [ 582.374033] Internal error: Oops: 96000007 [#1] SMP [ 582.374468] Modules linked in:
> [ 582.374795] CPU: 1 PID: 525 Comm: ping Not tainted 5.8.0-rc6+ #3 [
> 582.375468] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0
> 02/06/2015 [ 582.376215] pstate: 20400005 (nzCv daif +PAN -UAO
> BTYPE=--) [ 582.376805] pc : __ip_local_out+0x84/0x188 [ 582.377234]
> lr : ip_local_out+0x34/0x68 [ 582.377635] sp : ffff800013263440 [
> 582.377986] x29: ffff800013263440 x28: 0000000000000001 [ 582.378536]
> x27: ffff8000111d2018 x26: ffff8000114cba80 [ 582.379093] x25:
> ffff0000ec4e7400 x24: 0000000000000000 [ 582.379653] x23:
> 0000000000000062 x22: ffff8000114c9000 [ 582.380221] x21:
> ffff0000d97ac600 x20: ffff0000ec519000 [ 582.380778] x19:
> ffff8000115b5bc0 x18: 0000000000000000 [ 582.381324] x17:
> 0000000000000000 x16: 0000000000000000 [ 582.381876] x15:
> 0000000000000000 x14: 0000000000000000 [ 582.382431] x13:
> 0000000000000000 x12: 0000000000000001 [ 582.382986] x11:
> ffff800010d21838 x10: 0000000000000001 [ 582.383567] x9 :
> 0000000000000001 x8 : 0000000000000000 [ 582.384136] x7 :
> 0000000000000000 x6 : ffff0000ec4e5e00 [ 582.384693] x5 :
> 024079ca54000184 x4 : ffff0000ec4e5e10 [ 582.385246] x3 :
> 0000000000000000 x2 : ffff0004ec4e5e20 [ 582.385808] x1 :
> ffff0000f85f0000 x0 : 031d079626a9c7ae [ 582.386365] Call trace:
> [ 582.386629] __ip_local_out+0x84/0x188 [ 582.387030]
> ip_local_out+0x34/0x68 [ 582.387400] ipvlan_queue_xmit+0x548/0x5c0 [
> 582.387845] ipvlan_start_xmit+0x2c/0x90 [ 582.388283]
> dev_hard_start_xmit+0xb4/0x260 [ 582.388732]
> sch_direct_xmit+0x1b4/0x550 [ 582.389145] __qdisc_run+0x140/0x648 [
> 582.389524] __dev_queue_xmit+0x6a4/0x8b8 [ 582.389948]
> dev_queue_xmit+0x24/0x30 [ 582.390339] ip_finish_output2+0x324/0x580
> [ 582.390770] __ip_finish_output+0x130/0x218 [ 582.391218]
> ip_finish_output+0x38/0xd0 [ 582.391633] ip_output+0xb4/0x130 [
> 582.391984] ip_local_out+0x58/0x68 [ 582.392369]
> ip_send_skb+0x2c/0x88 [ 582.392729] ip_push_pending_frames+0x44/0x50
> [ 582.393189] raw_sendmsg+0x7a4/0x988 [ 582.393569]
> inet_sendmsg+0x4c/0x78 [ 582.393942] sock_sendmsg+0x58/0x68 [
> 582.394311] ____sys_sendmsg+0x284/0x2c0 [ 582.394721]
> ___sys_sendmsg+0x90/0xd0 [ 582.395113] __sys_sendmsg+0x78/0xd0 [
> 582.395504] __arm64_sys_sendmsg+0x2c/0x38 [ 582.395942]
> el0_svc_common.constprop.2+0x70/0x128
> [ 582.396472] do_el0_svc+0x34/0xa0
> [ 582.396834] el0_sync_handler+0xec/0x128 [ 582.397249]
> el0_sync+0x140/0x180 [ 582.397611] Code: ab030005 91001442 9a030000
> 8b020882 (b8404423) [ 582.398264] ---[ end trace 92adb54c8611f8c5
> ]--- [ 582.398754] Kernel panic - not syncing: Fatal exception in
> interrupt [ 582.399481] SMP: stopping secondary CPUs [ 582.399923]
> Kernel Offset: 0xc0000 from 0xffff800010000000 [ 582.400561]
> PHYS_OFFSET: 0x40000000 [ 582.400939] CPU features: 0x040002,22a08238
> [ 582.401380] Memory Limit: none [ 582.401710] ---[ end Kernel panic
> - not syncing: Fatal exception in interrupt ]---
>
> This panic is because the ip header is corrupted. The ihl of the ip header is error，this cause ip_fast_csum access the illegal address.
> 23 static inline __sum16 ip_fast_csum(const void *iph, unsigned int
> ihl)
> 24 {
> 25 __uint128_t tmp;
> 26 u64 sum;
> 27
> 28 tmp = *(const __uint128_t *)iph;
> 29 iph += 16;
> 30 ihl -= 4; -----here, if ihl is smaller than 5, the next will access the illegal address.
Well, the bug is there then.
Code for other arches is different.
x86 for instance has a test for silly ihl
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) { unsigned int sum;
asm(" movl (%1), %0\n"
" subl $4, %2\n"
" jbe 2f\n" --- here
" addl 4(%1), %0\n"
" adcl 8(%1), %0\n"
" adcl 12(%1), %0\n"
"1: adcl 16(%1), %0\n"
" lea 4(%1), %1\n"
" decl %2\n"
" jne 1b\n"
" adcl $0, %0\n"
" movl %0, %2\n"
" shrl $16, %0\n"
" addw %w2, %w0\n"
" adcl $0, %0\n"
" notl %0\n"
"2:"
/* Since the input registers which are loaded with iph and ihl
are modified, we must also specify them as outputs, or gcc
will assume they contain their original values. */
: "=r" (sum), "=r" (iph), "=r" (ihl)
: "1" (iph), "2" (ihl)
: "memory");
return (__force __sum16)sum;
}
> 31 tmp += ((tmp >> 64) | (tmp << 64));
> 32 sum = tmp >> 64;
> 33 do {
> 34 sum += *(const u32 *)iph;
> 35 iph += 4;
> 36 } while (--ihl);
> 37
> 38 sum += ((sum >> 32) | (sum << 32));
> 39 return csum_fold((__force u32)(sum >> 32));
> 40 }
>
> I think this panic may be a problem, thanks.
>
>
>
> -----邮件原件-----
> 发件人: Cong Wang [mailto:xiyou.wangcong@...il.com]
> 发送时间: Wednesday, July 22, 2020 3:39
> 收件人: Guodeqing (A) <geffrey.guo@...wei.com>
> 抄送: David Miller <davem@...emloft.net>; Jakub Kicinski
> <kuba@...nel.org>; Mahesh Bandewar <maheshb@...gle.com>; Eric Dumazet
> <edumazet@...gle.com>; Linux Kernel Network Developers
> <netdev@...r.kernel.org>
> 主题: Re: [PATCH] ipvlan: add the check of ip header checksum
>
> On Tue, Jul 21, 2020 at 6:17 AM guodeqing <geffrey.guo@...wei.com> wrote:
> >
> > The ip header checksum can be error in the following steps.
> > $ ip netns add ns1
> > $ ip link add gw link eth0 type ipvlan $ ip addr add 168.16.0.1/24
> > dev gw $ ip link set dev gw up $ ip link add ip1 link eth0 type
> > ipvlan $ ip link set ip1 netns ns1 $ ip netns exec ns1 ip link set
> > ip1 up $ ip netns exec ns1 ip addr add 168.16.0.2/24 dev ip1 $ ip
> > netns exec ns1 tc qdisc add dev ip1 root netem corrupt 50% $ ip
> > netns exec ns1 ping
> > 168.16.0.1
> >
> > The ip header of a packet maybe modified when it steps in
> > ipvlan_process_v4_outbound because of the netem, the corruptted
> > packets should be dropped.
>
> This does not make much sense, as you intentionally corrupt the header. More importantly, the check you add is too late, right?
> ipvlan_xmit_mode_l3() already does the addr lookup with IP header,
>
> Thanks.
>
> -----邮件原件-----
> 发件人: David Miller [mailto:davem@...emloft.net]
> 发送时间: Thursday, July 23, 2020 4:04
> 收件人: Guodeqing (A) <geffrey.guo@...wei.com>
> 抄送: kuba@...nel.org; maheshb@...gle.com; edumazet@...gle.com;
> netdev@...r.kernel.org
> 主题: Re: [PATCH,v2] ipvlan: add the check of ip header checksum
>
> From: guodeqing <geffrey.guo@...wei.com>
> Date: Wed, 22 Jul 2020 17:18:19 +0800
>
> > The ip header checksum can be error in the following steps.
>
> You did not respond to my feedback from your previous submissions.
>
> Packets created inside of the kernel have correct checksums, and the ipvlan driver can depend upon this precondition.
>
> I am not applying this patch, sorry.
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