4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Edward Cree ecree@solarflare.com
[ Upstream commit 22f6bbb7bcfcef0b373b0502a7ff390275c575dd ]
list_del() leaves the skb->next pointer poisoned, which can then lead to a crash in e.g. OVS forwarding. For example, setting up an OVS VXLAN forwarding bridge on sfc as per:
======== $ ovs-vsctl show 5dfd9c47-f04b-4aaa-aa96-4fbb0a522a30 Bridge "br0" Port "br0" Interface "br0" type: internal Port "enp6s0f0" Interface "enp6s0f0" Port "vxlan0" Interface "vxlan0" type: vxlan options: {key="1", local_ip="10.0.0.5", remote_ip="10.0.0.4"} ovs_version: "2.5.0" ======== (where 10.0.0.5 is an address on enp6s0f1) and sending traffic across it will lead to the following panic: ======== general protection fault: 0000 [#1] SMP PTI CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.20.0-rc3-ehc+ #701 Hardware name: Dell Inc. PowerEdge R710/0M233H, BIOS 6.4.0 07/23/2013 RIP: 0010:dev_hard_start_xmit+0x38/0x200 Code: 53 48 89 fb 48 83 ec 20 48 85 ff 48 89 54 24 08 48 89 4c 24 18 0f 84 ab 01 00 00 48 8d 86 90 00 00 00 48 89 f5 48 89 44 24 10 <4c> 8b 33 48 c7 03 00 00 00 00 48 8b 05 c7 d1 b3 00 4d 85 f6 0f 95 RSP: 0018:ffff888627b437e0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: dead000000000100 RCX: ffff88862279c000 RDX: ffff888614a342c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888618a88000 R08: 0000000000000001 R09: 00000000000003e8 R10: 0000000000000000 R11: ffff888614a34140 R12: 0000000000000000 R13: 0000000000000062 R14: dead000000000100 R15: ffff888616430000 FS: 0000000000000000(0000) GS:ffff888627b40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6d2bc6d000 CR3: 000000000200a000 CR4: 00000000000006e0 Call Trace: <IRQ> __dev_queue_xmit+0x623/0x870 ? masked_flow_lookup+0xf7/0x220 [openvswitch] ? ep_poll_callback+0x101/0x310 do_execute_actions+0xaba/0xaf0 [openvswitch] ? __wake_up_common+0x8a/0x150 ? __wake_up_common_lock+0x87/0xc0 ? queue_userspace_packet+0x31c/0x5b0 [openvswitch] ovs_execute_actions+0x47/0x120 [openvswitch] ovs_dp_process_packet+0x7d/0x110 [openvswitch] ovs_vport_receive+0x6e/0xd0 [openvswitch] ? dst_alloc+0x64/0x90 ? rt_dst_alloc+0x50/0xd0 ? ip_route_input_slow+0x19a/0x9a0 ? __udp_enqueue_schedule_skb+0x198/0x1b0 ? __udp4_lib_rcv+0x856/0xa30 ? __udp4_lib_rcv+0x856/0xa30 ? cpumask_next_and+0x19/0x20 ? find_busiest_group+0x12d/0xcd0 netdev_frame_hook+0xce/0x150 [openvswitch] __netif_receive_skb_core+0x205/0xae0 __netif_receive_skb_list_core+0x11e/0x220 netif_receive_skb_list+0x203/0x460 ? __efx_rx_packet+0x335/0x5e0 [sfc] efx_poll+0x182/0x320 [sfc] net_rx_action+0x294/0x3c0 __do_softirq+0xca/0x297 irq_exit+0xa6/0xb0 do_IRQ+0x54/0xd0 common_interrupt+0xf/0xf </IRQ> ======== So, in all listified-receive handling, instead pull skbs off the lists with skb_list_del_init().
Fixes: 9af86f933894 ("net: core: fix use-after-free in __netif_receive_skb_list_core") Fixes: 7da517a3bc52 ("net: core: Another step of skb receive list processing") Fixes: a4ca8b7df73c ("net: ipv4: fix drop handling in ip_list_rcv() and ip_list_rcv_finish()") Fixes: d8269e2cbf90 ("net: ipv6: listify ipv6_rcv() and ip6_rcv_finish()") Signed-off-by: Edward Cree ecree@solarflare.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/skbuff.h | 11 +++++++++++ net/core/dev.c | 8 ++++---- net/ipv4/ip_input.c | 4 ++-- net/ipv6/ip6_input.c | 4 ++-- 4 files changed, 19 insertions(+), 8 deletions(-)
--- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1355,6 +1355,17 @@ static inline void skb_zcopy_abort(struc } }
+static inline void skb_mark_not_on_list(struct sk_buff *skb) +{ + skb->next = NULL; +} + +static inline void skb_list_del_init(struct sk_buff *skb) +{ + __list_del_entry(&skb->list); + skb_mark_not_on_list(skb); +} + /** * skb_queue_empty - check if a queue is empty * @list: queue head --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4981,7 +4981,7 @@ static void __netif_receive_skb_list_cor struct net_device *orig_dev = skb->dev; struct packet_type *pt_prev = NULL;
- list_del(&skb->list); + skb_list_del_init(skb); __netif_receive_skb_core(skb, pfmemalloc, &pt_prev); if (!pt_prev) continue; @@ -5137,7 +5137,7 @@ static void netif_receive_skb_list_inter INIT_LIST_HEAD(&sublist); list_for_each_entry_safe(skb, next, head, list) { net_timestamp_check(netdev_tstamp_prequeue, skb); - list_del(&skb->list); + skb_list_del_init(skb); if (!skb_defer_rx_timestamp(skb)) list_add_tail(&skb->list, &sublist); } @@ -5148,7 +5148,7 @@ static void netif_receive_skb_list_inter rcu_read_lock(); list_for_each_entry_safe(skb, next, head, list) { xdp_prog = rcu_dereference(skb->dev->xdp_prog); - list_del(&skb->list); + skb_list_del_init(skb); if (do_xdp_generic(xdp_prog, skb) == XDP_PASS) list_add_tail(&skb->list, &sublist); } @@ -5167,7 +5167,7 @@ static void netif_receive_skb_list_inter
if (cpu >= 0) { /* Will be handled, remove from list */ - list_del(&skb->list); + skb_list_del_init(skb); enqueue_to_backlog(skb, cpu, &rflow->last_qtail); } } --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -551,7 +551,7 @@ static void ip_list_rcv_finish(struct ne list_for_each_entry_safe(skb, next, head, list) { struct dst_entry *dst;
- list_del(&skb->list); + skb_list_del_init(skb); /* if ingress device is enslaved to an L3 master device pass the * skb to its handler for processing */ @@ -598,7 +598,7 @@ void ip_list_rcv(struct list_head *head, struct net_device *dev = skb->dev; struct net *net = dev_net(dev);
- list_del(&skb->list); + skb_list_del_init(skb); skb = ip_rcv_core(skb, net); if (skb == NULL) continue; --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -95,7 +95,7 @@ static void ip6_list_rcv_finish(struct n list_for_each_entry_safe(skb, next, head, list) { struct dst_entry *dst;
- list_del(&skb->list); + skb_list_del_init(skb); /* if ingress device is enslaved to an L3 master device pass the * skb to its handler for processing */ @@ -295,7 +295,7 @@ void ipv6_list_rcv(struct list_head *hea struct net_device *dev = skb->dev; struct net *net = dev_net(dev);
- list_del(&skb->list); + skb_list_del_init(skb); skb = ip6_rcv_core(skb, dev, net); if (skb == NULL) continue;