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Message-Id: <1593939229-8191-1-git-send-email-martinvarghesenokia@gmail.com>
Date: Sun, 5 Jul 2020 14:23:49 +0530
From: Martin Varghese <martinvarghesenokia@...il.com>
To: netdev@...r.kernel.org, davem@...emloft.net
Cc: Martin Varghese <martin.varghese@...ia.com>
Subject: [PATCH net] net: Added pointer check for dst->ops->neigh_lookup in dst_neigh_lookup_skb
From: Martin Varghese <martin.varghese@...ia.com>
The packets from tunnel devices (eg bareudp) may have only
metadata in the dst pointer of skb. Hence a pointer check of
neigh_lookup is needed in dst_neigh_lookup_skb
Kernel crashes when packets from bareudp device is processed in
the kernel neighbour subsytem.
[ 133.384484] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 133.385240] #PF: supervisor instruction fetch in kernel mode
[ 133.385828] #PF: error_code(0x0010) - not-present page
[ 133.386603] PGD 0 P4D 0
[ 133.386875] Oops: 0010 [#1] SMP PTI
[ 133.387275] CPU: 0 PID: 5045 Comm: ping Tainted: G W 5.8.0-rc2+ #15
[ 133.388052] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 133.391076] RIP: 0010:0x0
[ 133.392401] Code: Bad RIP value.
[ 133.394029] RSP: 0018:ffffb79980003d50 EFLAGS: 00010246
[ 133.396656] RAX: 0000000080000102 RBX: ffff9de2fe0d6600 RCX: ffff9de2fe5e9d00
[ 133.399018] RDX: 0000000000000000 RSI: ffff9de2fe5e9d00 RDI: ffff9de2fc21b400
[ 133.399685] RBP: ffff9de2fe5e9d00 R08: 0000000000000000 R09: 0000000000000000
[ 133.400350] R10: ffff9de2fbc6be22 R11: ffff9de2fe0d6600 R12: ffff9de2fc21b400
[ 133.401010] R13: ffff9de2fe0d6628 R14: 0000000000000001 R15: 0000000000000003
[ 133.401667] FS: 00007fe014918740(0000) GS:ffff9de2fec00000(0000) knlGS:0000000000000000
[ 133.402412] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 133.402948] CR2: ffffffffffffffd6 CR3: 000000003bb72000 CR4: 00000000000006f0
[ 133.403611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 133.404270] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 133.404933] Call Trace:
[ 133.405169] <IRQ>
[ 133.405367] __neigh_update+0x5a4/0x8f0
[ 133.405734] arp_process+0x294/0x820
[ 133.406076] ? __netif_receive_skb_core+0x866/0xe70
[ 133.406557] arp_rcv+0x129/0x1c0
[ 133.406882] __netif_receive_skb_one_core+0x95/0xb0
[ 133.407340] process_backlog+0xa7/0x150
[ 133.407705] net_rx_action+0x2af/0x420
[ 133.408457] __do_softirq+0xda/0x2a8
[ 133.408813] asm_call_on_stack+0x12/0x20
[ 133.409290] </IRQ>
[ 133.409519] do_softirq_own_stack+0x39/0x50
[ 133.410036] do_softirq+0x50/0x60
[ 133.410401] __local_bh_enable_ip+0x50/0x60
[ 133.410871] ip_finish_output2+0x195/0x530
[ 133.411288] ip_output+0x72/0xf0
[ 133.411673] ? __ip_finish_output+0x1f0/0x1f0
[ 133.412122] ip_send_skb+0x15/0x40
[ 133.412471] raw_sendmsg+0x853/0xab0
[ 133.412855] ? insert_pfn+0xfe/0x270
[ 133.413827] ? vvar_fault+0xec/0x190
[ 133.414772] sock_sendmsg+0x57/0x80
[ 133.415685] __sys_sendto+0xdc/0x160
[ 133.416605] ? syscall_trace_enter+0x1d4/0x2b0
[ 133.417679] ? __audit_syscall_exit+0x1d9/0x280
[ 133.418753] ? __prepare_exit_to_usermode+0x5d/0x1a0
[ 133.419819] __x64_sys_sendto+0x24/0x30
[ 133.420848] do_syscall_64+0x4d/0x90
[ 133.421768] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 133.422833] RIP: 0033:0x7fe013689c03
[ 133.423749] Code: Bad RIP value.
[ 133.424624] RSP: 002b:00007ffc7288f418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 133.425940] RAX: ffffffffffffffda RBX: 000056151fc63720 RCX: 00007fe013689c03
[ 133.427225] RDX: 0000000000000040 RSI: 000056151fc63720 RDI: 0000000000000003
[ 133.428481] RBP: 00007ffc72890b30 R08: 000056151fc60500 R09: 0000000000000010
[ 133.429757] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040
[ 133.431041] R13: 000056151fc636e0 R14: 000056151fc616bc R15: 0000000000000080
[ 133.432481] Modules linked in: mpls_iptunnel act_mirred act_tunnel_key cls_flower sch_ingress veth mpls_router ip_tunnel bareudp ip6_udp_tunnel udp_tunnel macsec udp_diag inet_diag unix_diag af_packet_diag netlink_diag binfmt_misc xt_MASQUERADE iptable_nat xt_addrtype xt_conntrack nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc ebtable_filter ebtables overlay ip6table_filter ip6_tables iptable_filter sunrpc ext4 mbcache jbd2 pcspkr i2c_piix4 virtio_balloon joydev ip_tables xfs libcrc32c ata_generic qxl pata_acpi drm_ttm_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ata_piix libata virtio_net net_failover virtio_console failover virtio_blk i2c_core virtio_pci virtio_ring serio_raw floppy virtio dm_mirror dm_region_hash dm_log dm_mod
[ 133.444045] CR2: 0000000000000000
[ 133.445082] ---[ end trace f4aeee1958fd1638 ]---
[ 133.446236] RIP: 0010:0x0
[ 133.447180] Code: Bad RIP value.
[ 133.448152] RSP: 0018:ffffb79980003d50 EFLAGS: 00010246
[ 133.449363] RAX: 0000000080000102 RBX: ffff9de2fe0d6600 RCX: ffff9de2fe5e9d00
[ 133.450835] RDX: 0000000000000000 RSI: ffff9de2fe5e9d00 RDI: ffff9de2fc21b400
[ 133.452237] RBP: ffff9de2fe5e9d00 R08: 0000000000000000 R09: 0000000000000000
[ 133.453722] R10: ffff9de2fbc6be22 R11: ffff9de2fe0d6600 R12: ffff9de2fc21b400
[ 133.455149] R13: ffff9de2fe0d6628 R14: 0000000000000001 R15: 0000000000000003
[ 133.456520] FS: 00007fe014918740(0000) GS:ffff9de2fec00000(0000) knlGS:0000000000000000
[ 133.458046] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 133.459342] CR2: ffffffffffffffd6 CR3: 000000003bb72000 CR4: 00000000000006f0
[ 133.460782] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 133.462240] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 133.463697] Kernel panic - not syncing: Fatal exception in interrupt
[ 133.465226] Kernel Offset: 0xfa00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 133.467025] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Fixes: aaa0c23cb901 ("Fix dst_neigh_lookup/dst_neigh_lookup_skb return value handling bug")
Signed-off-by: Martin Varghese <martin.varghese@...ia.com>
---
include/net/dst.h | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/net/dst.h b/include/net/dst.h
index 07adfac..852d8fb 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -400,7 +400,15 @@ static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, co
static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
struct sk_buff *skb)
{
- struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
+ struct neighbour *n = NULL;
+
+ /* The packets from tunnel devices (eg bareudp) may have only
+ * metadata in the dst pointer of skb. Hence a pointer check of
+ * neigh_lookup is needed.
+ */
+ if (dst->ops->neigh_lookup)
+ n = dst->ops->neigh_lookup(dst, skb, NULL);
+
return IS_ERR(n) ? NULL : n;
}
--
1.8.3.1
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