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:eduma...@google.com] 发送时间: Thursday, July 23, 2020 10:15 收件人: Guodeqing (A) <geffrey....@huawei.com> 抄送: David Miller <da...@davemloft.net>; k...@kernel.org; mahe...@google.com; netdev@vger.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....@huawei.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.wangc...@gmail.com] > 发送时间: Wednesday, July 22, 2020 3:39 > 收件人: Guodeqing (A) <geffrey....@huawei.com> > 抄送: David Miller <da...@davemloft.net>; Jakub Kicinski > <k...@kernel.org>; Mahesh Bandewar <mahe...@google.com>; Eric Dumazet > <eduma...@google.com>; Linux Kernel Network Developers > <netdev@vger.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....@huawei.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:da...@davemloft.net] > 发送时间: Thursday, July 23, 2020 4:04 > 收件人: Guodeqing (A) <geffrey....@huawei.com> > 抄送: k...@kernel.org; mahe...@google.com; eduma...@google.com; > netdev@vger.kernel.org > 主题: Re: [PATCH,v2] ipvlan: add the check of ip header checksum > > From: guodeqing <geffrey....@huawei.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.
