ip6_offload: check segs for NULL in ipv6_gso_segment.
[ Upstream commit 6b6ebb6b ] segs needs to be checked for being NULL in ipv6_gso_segment() before calling skb_shinfo(segs), otherwise kernel can run into a NULL-pointer dereference: [ 97.811262] BUG: unable to handle kernel NULL pointer dereference at 00000000000000cc [ 97.819112] IP: [<ffffffff816e52f9>] ipv6_gso_segment+0x119/0x2f0 [ 97.825214] PGD 0 [ 97.827047] [ 97.828540] Oops: 0000 [#1] SMP [ 97.831678] Modules linked in: vhost_net vhost macvtap macvlan nfsv3 rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 tun ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter bridge stp llc snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic snd_hda_intel snd_hda_codec edac_mce_amd snd_hda_core edac_core snd_hwdep kvm_amd snd_seq kvm snd_seq_device snd_pcm irqbypass snd_timer ppdev parport_serial snd parport_pc k10temp pcspkr soundcore parport sp5100_tco shpchp sg wmi i2c_piix4 acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sr_mod cdrom sd_mod ata_generic pata_acpi amdkfd amd_iommu_v2 radeon broadcom bcm_phy_lib i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm ahci serio_raw tg3 firewire_ohci libahci pata_atiixp drm ptp libata firewire_core pps_core i2c_core crc_itu_t fjes dm_mirror dm_region_hash dm_log dm_mod [ 97.927721] CPU: 1 PID: 3504 Comm: vhost-3495 Not tainted 4.9.0-7.el7.test.x86_64 #1 [ 97.935457] Hardware name: AMD Snook/Snook, BIOS ESK0726A 07/26/2010 [ 97.941806] task: ffff880129a1c080 task.stack: ffffc90001bcc000 [ 97.947720] RIP: 0010:[<ffffffff816e52f9>] [<ffffffff816e52f9>] ipv6_gso_segment+0x119/0x2f0 [ 97.956251] RSP: 0018:ffff88012fc43a10 EFLAGS: 00010207 [ 97.961557] RAX: 0000000000000000 RBX: ffff8801292c8700 RCX: 0000000000000594 [ 97.968687] RDX: 0000000000000593 RSI: ffff880129a846c0 RDI: 0000000000240000 [ 97.975814] RBP: ffff88012fc43a68 R08: ffff880129a8404e R09: 0000000000000000 [ 97.982942] R10: 0000000000000000 R11: ffff880129a84076 R12: 00000020002949b3 [ 97.990070] R13: ffff88012a580000 R14: 0000000000000000 R15: ffff88012a580000 [ 97.997198] FS: 0000000000000000(0000) GS:ffff88012fc40000(0000) knlGS:0000000000000000 [ 98.005280] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 98.011021] CR2: 00000000000000cc CR3: 0000000126c5d000 CR4: 00000000000006e0 [ 98.018149] Stack: [ 98.020157] 00000000ffffffff ffff88012fc43ac8 ffffffffa017ad0a 000000000000000e [ 98.027584] 0000001300000000 0000000077d59998 ffff8801292c8700 00000020002949b3 [ 98.035010] ffff88012a580000 0000000000000000 ffff88012a580000 ffff88012fc43a98 [ 98.042437] Call Trace: [ 98.044879] <IRQ> [ 98.046803] [<ffffffffa017ad0a>] ? tg3_start_xmit+0x84a/0xd60 [tg3] [ 98.053156] [<ffffffff815eeee0>] skb_mac_gso_segment+0xb0/0x130 [ 98.059158] [<ffffffff815eefd3>] __skb_gso_segment+0x73/0x110 [ 98.064985] [<ffffffff815ef40d>] validate_xmit_skb+0x12d/0x2b0 [ 98.070899] [<ffffffff815ef5d2>] validate_xmit_skb_list+0x42/0x70 [ 98.077073] [<ffffffff81618560>] sch_direct_xmit+0xd0/0x1b0 [ 98.082726] [<ffffffff815efd86>] __dev_queue_xmit+0x486/0x690 [ 98.088554] [<ffffffff8135c135>] ? cpumask_next_and+0x35/0x50 [ 98.094380] [<ffffffff815effa0>] dev_queue_xmit+0x10/0x20 [ 98.099863] [<ffffffffa09ce057>] br_dev_queue_push_xmit+0xa7/0x170 [bridge] [ 98.106907] [<ffffffffa09ce161>] br_forward_finish+0x41/0xc0 [bridge] [ 98.113430] [<ffffffff81627cf2>] ? nf_iterate+0x52/0x60 [ 98.118735] [<ffffffff81627d6b>] ? nf_hook_slow+0x6b/0xc0 [ 98.124216] [<ffffffffa09ce32c>] __br_forward+0x14c/0x1e0 [bridge] [ 98.130480] [<ffffffffa09ce120>] ? br_dev_queue_push_xmit+0x170/0x170 [bridge] [ 98.137785] [<ffffffffa09ce4bd>] br_forward+0x9d/0xb0 [bridge] [ 98.143701] [<ffffffffa09cfbb7>] br_handle_frame_finish+0x267/0x560 [bridge] [ 98.150834] [<ffffffffa09d0064>] br_handle_frame+0x174/0x2f0 [bridge] [ 98.157355] [<ffffffff8102fb89>] ? sched_clock+0x9/0x10 [ 98.162662] [<ffffffff810b63b2>] ? sched_clock_cpu+0x72/0xa0 [ 98.168403] [<ffffffff815eccf5>] __netif_receive_skb_core+0x1e5/0xa20 [ 98.174926] [<ffffffff813659f9>] ? timerqueue_add+0x59/0xb0 [ 98.180580] [<ffffffff815ed548>] __netif_receive_skb+0x18/0x60 [ 98.186494] [<ffffffff815ee625>] process_backlog+0x95/0x140 [ 98.192145] [<ffffffff815edccd>] net_rx_action+0x16d/0x380 [ 98.197713] [<ffffffff8170cff1>] __do_softirq+0xd1/0x283 [ 98.203106] [<ffffffff8170b2bc>] do_softirq_own_stack+0x1c/0x30 [ 98.209107] <EOI> [ 98.211029] [<ffffffff8108a5c0>] do_softirq+0x50/0x60 [ 98.216166] [<ffffffff815ec853>] netif_rx_ni+0x33/0x80 [ 98.221386] [<ffffffffa09eeff7>] tun_get_user+0x487/0x7f0 [tun] [ 98.227388] [<ffffffffa09ef3ab>] tun_sendmsg+0x4b/0x60 [tun] [ 98.233129] [<ffffffffa0b68932>] handle_tx+0x282/0x540 [vhost_net] [ 98.239392] [<ffffffffa0b68c25>] handle_tx_kick+0x15/0x20 [vhost_net] [ 98.245916] [<ffffffffa0abacfe>] vhost_worker+0x9e/0xf0 [vhost] [ 98.251919] [<ffffffffa0abac60>] ? vhost_umem_alloc+0x40/0x40 [vhost] [ 98.258440] [<ffffffff81003a47>] ? do_syscall_64+0x67/0x180 [ 98.264094] [<ffffffff810a44d9>] kthread+0xd9/0xf0 [ 98.268965] [<ffffffff810a4400>] ? kthread_park+0x60/0x60 [ 98.274444] [<ffffffff8170a4d5>] ret_from_fork+0x25/0x30 [ 98.279836] Code: 8b 93 d8 00 00 00 48 2b 93 d0 00 00 00 4c 89 e6 48 89 df 66 89 93 c2 00 00 00 ff 10 48 3d 00 f0 ff ff 49 89 c2 0f 87 52 01 00 00 <41> 8b 92 cc 00 00 00 48 8b 80 d0 00 00 00 44 0f b7 74 10 06 66 [ 98.299425] RIP [<ffffffff816e52f9>] ipv6_gso_segment+0x119/0x2f0 [ 98.305612] RSP <ffff88012fc43a10> [ 98.309094] CR2: 00000000000000cc [ 98.312406] ---[ end trace 726a2c7a2d2d78d0 ]--- Signed-off-by:Artem Savkov <asavkov@redhat.com> Acked-by:
Eric Dumazet <edumazet@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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