kernel/linux.git/include/net/dst.h, branch v5.4.203

net: Added pointer check for dst->ops->neigh_lookup in dst_neigh_lookup_skb

2020-07-22T07:32:47+00:00

[ Upstream commit 394de110a73395de2ca4516b0de435e91b11b604 ] 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] [ 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] [ 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/dst: do not confirm neighbor for vxlan and geneve pmtu update

2020-01-04T18:19:05+00:00

[ Upstream commit f081042d128a0c7acbd67611def62e1b52e2d294 ] When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end, we should not call dst_confirm_neigh() as there is no two-way communication. So disable the neigh confirm for vxlan and geneve pmtu update. v5: No change. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path") Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path") Reviewed-by: Guillaume Nault Tested-by: Guillaume Nault Acked-by: David Ahern Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/dst: add new function skb_dst_update_pmtu_no_confirm

2020-01-04T18:19:01+00:00

[ Upstream commit 07dc35c6e3cc3c001915d05f5bf21f80a39a0970 ] Add a new function skb_dst_update_pmtu_no_confirm() for callers who need update pmtu but should not do neighbor confirm. v5: No change. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Reviewed-by: Guillaume Nault Acked-by: David Ahern Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: add bool confirm_neigh parameter for dst_ops.update_pmtu

2020-01-04T18:18:58+00:00

[ Upstream commit bd085ef678b2cc8c38c105673dfe8ff8f5ec0c57 ] The MTU update code is supposed to be invoked in response to real networking events that update the PMTU. In IPv6 PMTU update function __ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor confirmed time. But for tunnel code, it will call pmtu before xmit, like: - tnl_update_pmtu() - skb_dst_update_pmtu() - ip6_rt_update_pmtu() - __ip6_rt_update_pmtu() - dst_confirm_neigh() If the tunnel remote dst mac address changed and we still do the neigh confirm, we will not be able to update neigh cache and ping6 remote will failed. So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we should not be invoking dst_confirm_neigh() as we have no evidence of successful two-way communication at this point. On the other hand it is also important to keep the neigh reachability fresh for TCP flows, so we cannot remove this dst_confirm_neigh() call. To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu to choose whether we should do neigh update or not. I will add the parameter in this patch and set all the callers to true to comply with the previous way, and fix the tunnel code one by one on later patches. v5: No change. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Suggested-by: David Miller Reviewed-by: Guillaume Nault Acked-by: David Ahern Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: dst: Force 4-byte alignment of dst_metrics

2019-12-31T15:41:17+00:00

[ Upstream commit 258a980d1ec23e2c786e9536a7dd260bea74bae6 ] When storing a pointer to a dst_metrics structure in dst_entry._metrics, two flags are added in the least significant bits of the pointer value. Hence this assumes all pointers to dst_metrics structures have at least 4-byte alignment. However, on m68k, the minimum alignment of 32-bit values is 2 bytes, not 4 bytes. Hence in some kernel builds, dst_default_metrics may be only 2-byte aligned, leading to obscure boot warnings like: WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x44/0x9a refcount_t: underflow; use-after-free. Modules linked in: CPU: 0 PID: 7 Comm: ksoftirqd/0 Tainted: G W 5.5.0-rc2-atari-01448-g114a1a1038af891d-dirty #261 Stack from 10835e6c: 10835e6c 0038134f 00023fa6 00394b0f 0000001c 00000009 00321560 00023fea 00394b0f 0000001c 001a70f8 00000009 00000000 10835eb4 00000001 00000000 04208040 0000000a 00394b4a 10835ed4 00043aa8 001a70f8 00394b0f 0000001c 00000009 00394b4a 0026aba8 003215a4 00000003 00000000 0026d5a8 00000001 003215a4 003a4361 003238d6 000001f0 00000000 003215a4 10aa3b00 00025e84 003ddb00 10834000 002416a8 10aa3b00 00000000 00000080 000aa038 0004854a Call Trace: [<00023fa6>] __warn+0xb2/0xb4 [<00023fea>] warn_slowpath_fmt+0x42/0x64 [<001a70f8>] refcount_warn_saturate+0x44/0x9a [<00043aa8>] printk+0x0/0x18 [<001a70f8>] refcount_warn_saturate+0x44/0x9a [<0026aba8>] refcount_sub_and_test.constprop.73+0x38/0x3e [<0026d5a8>] ipv4_dst_destroy+0x5e/0x7e [<00025e84>] __local_bh_enable_ip+0x0/0x8e [<002416a8>] dst_destroy+0x40/0xae Fix this by forcing 4-byte alignment of all dst_metrics structures. Fixes: e5fd387ad5b30ca3 ("ipv6: do not overwrite inetpeer metrics prematurely") Signed-off-by: Geert Uytterhoeven Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: dst.h: Fix shifting signed 32-bit value by 31 bits problem

2019-07-01T17:48:34+00:00

Fix DST_FEATURE_ECN_CA to use "U" cast to avoid shifting signed 32-bit value by 31 bits problem. Signed-off-by: Vandana BN Signed-off-by: David S. Miller

net: make skb_dst_force return true when dst is refcounted

2019-06-29T18:01:35+00:00

netfilter did not expect that skb_dst_force() can cause skb to lose its dst entry. I got a bug report with a skb->dst NULL dereference in netfilter output path. The backtrace contains nf_reinject(), so the dst might have been cleared when skb got queued to userspace. Other users were fixed via if (skb_dst(skb)) { skb_dst_force(skb); if (!skb_dst(skb)) goto handle_err; } But I think its preferable to make the 'dst might be cleared' part of the function explicit. In netfilter case, skb with a null dst is expected when queueing in prerouting hook, so drop skb for the other hooks. v2: v1 of this patch returned true in case skb had no dst entry. Eric said: Say if we have two skb_dst_force() calls for some reason on the same skb, only the first one will return false. This now returns false even when skb had no dst, as per Erics suggestion, so callers might need to check skb_dst() first before skb_dst_force(). Signed-off-by: Florian Westphal Signed-off-by: David S. Miller

net: dst: remove gc leftovers

2019-03-21T20:39:25+00:00

Get rid of some obsolete gc-related documentation and macros that were missed in commit 5b7c9a8ff828 ("net: remove dst gc related code"). CC: Wei Wang Signed-off-by: Julian Wiedmann Acked-by: Wei Wang Signed-off-by: David S. Miller

geneve, vxlan: Don't set exceptions if skb->len < mtu

2018-10-18T04:51:13+00:00

We shouldn't abuse exceptions: if the destination MTU is already higher than what we're transmitting, no exception should be created. Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path") Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path") Signed-off-by: Stefano Brivio Reviewed-by: Sabrina Dubroca Signed-off-by: David S. Miller

xfrm: Remove xfrmi interface ID from flowi

2018-07-20T08:14:41+00:00

In order to remove performance impact of having the extra u32 in every single flowi, this change removes the flowi_xfrm struct, prefering to take the if_id as a method parameter where needed. In the inbound direction, if_id is only needed during the __xfrm_check_policy() function, and the if_id can be determined at that point based on the skb. As such, xfrmi_decode_session() is only called with the skb in __xfrm_check_policy(). In the outbound direction, the only place where if_id is needed is the xfrm_lookup() call in xfrmi_xmit2(). With this change, the if_id is directly passed into the xfrm_lookup_with_ifid() call. All existing callers can still call xfrm_lookup(), which uses a default if_id of 0. This change does not change any behavior of XFRMIs except for improving overall system performance via flowi size reduction. This change has been tested against the Android Kernel Networking Tests: https://android.googlesource.com/kernel/tests/+/master/net/test Signed-off-by: Benedict Wong Signed-off-by: Steffen Klassert