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ipv6: ip6_append_data_mtu did not care about pmtudisc and frag_size
If the socket had an IPV6_MTU value set, ip6_append_data_mtu lost track
of this when appending the second frame on a corked socket. This results
in the following splat:
[37598.993962] ------------[ cut here ]------------
[37598.994008] kernel BUG at net/core/skbuff.c:2064!
[37598.994008] invalid opcode: 0000 [#1] SMP
[37598.994008] Modules linked in: tcp_lp uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core videodev media vfat fat usb_storage fuse ebtable_nat xt_CHECKSUM bridge stp llc ipt_MASQUERADE nf_conntrack_netbios_ns nf_conntrack_broadcast ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat
+nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i cxgb4 cxgb3i cxgb3 mdio libcxgbi ib_iser rdma_cm ib_addr iw_cm ib_cm ib_sa ib_mad ib_core iscsi_tcp libiscsi_tcp libiscsi
+scsi_transport_iscsi rfcomm bnep iTCO_wdt iTCO_vendor_support snd_hda_codec_conexant arc4 iwldvm mac80211 snd_hda_intel acpi_cpufreq mperf coretemp snd_hda_codec microcode cdc_wdm cdc_acm
[37598.994008] snd_hwdep cdc_ether snd_seq snd_seq_device usbnet mii joydev btusb snd_pcm bluetooth i2c_i801 e1000e lpc_ich mfd_core ptp iwlwifi pps_core snd_page_alloc mei cfg80211 snd_timer thinkpad_acpi snd tpm_tis soundcore rfkill tpm tpm_bios vhost_net tun macvtap macvlan kvm_intel kvm uinput binfmt_misc
+dm_crypt i915 i2c_algo_bit drm_kms_helper drm i2c_core wmi video
[37598.994008] CPU 0
[37598.994008] Pid: 27320, comm: t2 Not tainted 3.9.6-200.fc18.x86_64 #1 LENOVO 27744PG/27744PG
[37598.994008] RIP: 0010:[<ffffffff815443a5>] [<ffffffff815443a5>] skb_copy_and_csum_bits+0x325/0x330
[37598.994008] RSP: 0018:ffff88003670da18 EFLAGS: 00010202
[37598.994008] RAX: ffff88018105c018 RBX: 0000000000000004 RCX: 00000000000006c0
[37598.994008] RDX: ffff88018105a6c0 RSI: ffff88018105a000 RDI: ffff8801e1b0aa00
[37598.994008] RBP: ffff88003670da78 R08: 0000000000000000 R09: ffff88018105c040
[37598.994008] R10: ffff8801e1b0aa00 R11: 0000000000000000 R12: 000000000000fff8
[37598.994008] R13: 00000000000004fc R14: 00000000ffff0504 R15: 0000000000000000
[37598.994008] FS: 00007f28eea59740(0000) GS:ffff88023bc00000(0000) knlGS:0000000000000000
[37598.994008] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[37598.994008] CR2: 0000003d935789e0 CR3: 00000000365cb000 CR4: 00000000000407f0
[37598.994008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[37598.994008] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[37598.994008] Process t2 (pid: 27320, threadinfo ffff88003670c000, task ffff88022c162ee0)
[37598.994008] Stack:
[37598.994008] ffff88022e098a00 ffff88020f973fc0 0000000000000008 00000000000004c8
[37598.994008] ffff88020f973fc0 00000000000004c4 ffff88003670da78 ffff8801e1b0a200
[37598.994008] 0000000000000018 00000000000004c8 ffff88020f973fc0 00000000000004c4
[37598.994008] Call Trace:
[37598.994008] [<ffffffff815fc21f>] ip6_append_data+0xccf/0xfe0
[37598.994008] [<ffffffff8158d9f0>] ? ip_copy_metadata+0x1a0/0x1a0
[37598.994008] [<ffffffff81661f66>] ? _raw_spin_lock_bh+0x16/0x40
[37598.994008] [<ffffffff8161548d>] udpv6_sendmsg+0x1ed/0xc10
[37598.994008] [<ffffffff812a2845>] ? sock_has_perm+0x75/0x90
[37598.994008] [<ffffffff815c3693>] inet_sendmsg+0x63/0xb0
[37598.994008] [<ffffffff812a2973>] ? selinux_socket_sendmsg+0x23/0x30
[37598.994008] [<ffffffff8153a450>] sock_sendmsg+0xb0/0xe0
[37598.994008] [<ffffffff810135d1>] ? __switch_to+0x181/0x4a0
[37598.994008] [<ffffffff8153d97d>] sys_sendto+0x12d/0x180
[37598.994008] [<ffffffff810dfb64>] ? __audit_syscall_entry+0x94/0xf0
[37598.994008] [<ffffffff81020ed1>] ? syscall_trace_enter+0x231/0x240
[37598.994008] [<ffffffff8166a7e7>] tracesys+0xdd/0xe2
[37598.994008] Code: fe 07 00 00 48 c7 c7 04 28 a6 81 89 45 a0 4c 89 4d b8 44 89 5d a8 e8 1b ac b1 ff 44 8b 5d a8 4c 8b 4d b8 8b 45 a0 e9 cf fe ff ff <0f> 0b 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 89 e5 48
[37598.994008] RIP [<ffffffff815443a5>] skb_copy_and_csum_bits+0x325/0x330
[37598.994008] RSP <ffff88003670da18>
[37599.007323] ---[ end trace d69f6a17f8ac8eee ]---
While there, also check if path mtu discovery is activated for this
socket. The logic was adapted from ip6_append_data when first writing
on the corked socket.
This bug was introduced with commit
0c1833797a ("ipv6: fix incorrect ipsec
fragment").
v2:
a) Replace IPV6_PMTU_DISC_DO with IPV6_PMTUDISC_PROBE.
b) Don't pass ipv6_pinfo to ip6_append_data_mtu (suggestion by Gao
feng, thanks!).
c) Change mtu to unsigned int, else we get a warning about
non-matching types because of the min()-macro type-check.
Acked-by: Gao feng <gaofeng@cn.fujitsu.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Hannes Frederic Sowa
David S. Miller
parent
8822b64a0f
commit
75a493e60a
@ -1093,11 +1093,12 @@ static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
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return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
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}
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static void ip6_append_data_mtu(int *mtu,
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static void ip6_append_data_mtu(unsigned int *mtu,
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int *maxfraglen,
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unsigned int fragheaderlen,
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struct sk_buff *skb,
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struct rt6_info *rt)
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struct rt6_info *rt,
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bool pmtuprobe)
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{
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if (!(rt->dst.flags & DST_XFRM_TUNNEL)) {
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if (skb == NULL) {
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@ -1109,7 +1110,9 @@ static void ip6_append_data_mtu(int *mtu,
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* this fragment is not first, the headers
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* space is regarded as data space.
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*/
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*mtu = dst_mtu(rt->dst.path);
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*mtu = min(*mtu, pmtuprobe ?
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rt->dst.dev->mtu :
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dst_mtu(rt->dst.path));
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}
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*maxfraglen = ((*mtu - fragheaderlen) & ~7)
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+ fragheaderlen - sizeof(struct frag_hdr);
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@ -1126,11 +1129,10 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
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struct ipv6_pinfo *np = inet6_sk(sk);
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struct inet_cork *cork;
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struct sk_buff *skb, *skb_prev = NULL;
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unsigned int maxfraglen, fragheaderlen;
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unsigned int maxfraglen, fragheaderlen, mtu;
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int exthdrlen;
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int dst_exthdrlen;
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int hh_len;
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int mtu;
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int copy;
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int err;
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int offset = 0;
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@ -1287,7 +1289,9 @@ alloc_new_skb:
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/* update mtu and maxfraglen if necessary */
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if (skb == NULL || skb_prev == NULL)
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ip6_append_data_mtu(&mtu, &maxfraglen,
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fragheaderlen, skb, rt);
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fragheaderlen, skb, rt,
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np->pmtudisc ==
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IPV6_PMTUDISC_PROBE);
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skb_prev = skb;
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