From: Pablo Neira Ayuso pablo@netfilter.org
mainline inclusion from mainline-v6.9-rc5 commit 751de2012eafa4d46d8081056761fa0e9cc8a178 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9Q8LZ CVE: CVE-2024-27415
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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For historical reasons, when bridge device is in promisc mode, packets that are directed to the taps follow bridge input hook path. This patch adds a workaround to reset conntrack for these packets.
Jianbo Liu reports warning splats in their test infrastructure where cloned packets reach the br_netfilter input hook to confirm the conntrack object.
Scratch one bit from BR_INPUT_SKB_CB to annotate that this packet has reached the input hook because it is passed up to the bridge device to reach the taps.
[ 57.571874] WARNING: CPU: 1 PID: 0 at net/bridge/br_netfilter_hooks.c:616 br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.572749] Modules linked in: xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_isc si ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5ctl mlx5_core [ 57.575158] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0+ #19 [ 57.575700] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 57.576662] RIP: 0010:br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.577195] Code: fe ff ff 41 bd 04 00 00 00 be 04 00 00 00 e9 4a ff ff ff be 04 00 00 00 48 89 ef e8 f3 a9 3c e1 66 83 ad b4 00 00 00 04 eb 91 <0f> 0b e9 f1 fe ff ff 0f 0b e9 df fe ff ff 48 89 df e8 b3 53 47 e1 [ 57.578722] RSP: 0018:ffff88885f845a08 EFLAGS: 00010202 [ 57.579207] RAX: 0000000000000002 RBX: ffff88812dfe8000 RCX: 0000000000000000 [ 57.579830] RDX: ffff88885f845a60 RSI: ffff8881022dc300 RDI: 0000000000000000 [ 57.580454] RBP: ffff88885f845a60 R08: 0000000000000001 R09: 0000000000000003 [ 57.581076] R10: 00000000ffff1300 R11: 0000000000000002 R12: 0000000000000000 [ 57.581695] R13: ffff8881047ffe00 R14: ffff888108dbee00 R15: ffff88814519b800 [ 57.582313] FS: 0000000000000000(0000) GS:ffff88885f840000(0000) knlGS:0000000000000000 [ 57.583040] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 57.583564] CR2: 000000c4206aa000 CR3: 0000000103847001 CR4: 0000000000370eb0 [ 57.584194] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 57.584820] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 57.585440] Call Trace: [ 57.585721] <IRQ> [ 57.585976] ? __warn+0x7d/0x130 [ 57.586323] ? br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.586811] ? report_bug+0xf1/0x1c0 [ 57.587177] ? handle_bug+0x3f/0x70 [ 57.587539] ? exc_invalid_op+0x13/0x60 [ 57.587929] ? asm_exc_invalid_op+0x16/0x20 [ 57.588336] ? br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.588825] nf_hook_slow+0x3d/0xd0 [ 57.589188] ? br_handle_vlan+0x4b/0x110 [ 57.589579] br_pass_frame_up+0xfc/0x150 [ 57.589970] ? br_port_flags_change+0x40/0x40 [ 57.590396] br_handle_frame_finish+0x346/0x5e0 [ 57.590837] ? ipt_do_table+0x32e/0x430 [ 57.591221] ? br_handle_local_finish+0x20/0x20 [ 57.591656] br_nf_hook_thresh+0x4b/0xf0 [br_netfilter] [ 57.592286] ? br_handle_local_finish+0x20/0x20 [ 57.592802] br_nf_pre_routing_finish+0x178/0x480 [br_netfilter] [ 57.593348] ? br_handle_local_finish+0x20/0x20 [ 57.593782] ? nf_nat_ipv4_pre_routing+0x25/0x60 [nf_nat] [ 57.594279] br_nf_pre_routing+0x24c/0x550 [br_netfilter] [ 57.594780] ? br_nf_hook_thresh+0xf0/0xf0 [br_netfilter] [ 57.595280] br_handle_frame+0x1f3/0x3d0 [ 57.595676] ? br_handle_local_finish+0x20/0x20 [ 57.596118] ? br_handle_frame_finish+0x5e0/0x5e0 [ 57.596566] __netif_receive_skb_core+0x25b/0xfc0 [ 57.597017] ? __napi_build_skb+0x37/0x40 [ 57.597418] __netif_receive_skb_list_core+0xfb/0x220
Fixes: 62e7151ae3eb ("netfilter: bridge: confirm multicast packets before passing them up the stack") Reported-by: Jianbo Liu jianbol@nvidia.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org
Conflicts: net/bridge/br_input.c [The conflict occurs because the commit f4b7002a7076("net: bridge: add vlan mcast snooping knob") is not merged] Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com --- net/bridge/br_input.c | 15 +++++++++++---- net/bridge/br_netfilter_hooks.c | 6 ++++++ net/bridge/br_private.h | 1 + net/bridge/netfilter/nf_conntrack_bridge.c | 14 ++++++++++---- 4 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index 52dd0708fd14..add584eb1ae8 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -30,7 +30,7 @@ br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb) return netif_receive_skb(skb); }
-static int br_pass_frame_up(struct sk_buff *skb) +static int br_pass_frame_up(struct sk_buff *skb, bool promisc) { struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev; struct net_bridge *br = netdev_priv(brdev); @@ -69,6 +69,8 @@ static int br_pass_frame_up(struct sk_buff *skb) br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb), BR_MCAST_DIR_TX);
+ BR_INPUT_SKB_CB(skb)->promisc = promisc; + return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(indev), NULL, skb, indev, NULL, br_netif_receive_skb); @@ -83,6 +85,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb struct net_bridge_mdb_entry *mdst; bool local_rcv, mcast_hit = false; struct net_bridge *br; + bool promisc; u16 vid = 0; u8 state;
@@ -101,7 +104,9 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb if (p->flags & BR_LEARNING) br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
- local_rcv = !!(br->dev->flags & IFF_PROMISC); + promisc = !!(br->dev->flags & IFF_PROMISC); + local_rcv = promisc; + if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) { /* by definition the broadcast is also a multicast address */ if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) { @@ -163,7 +168,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb unsigned long now = jiffies;
if (test_bit(BR_FDB_LOCAL, &dst->flags)) - return br_pass_frame_up(skb); + return br_pass_frame_up(skb, false);
if (now != dst->used) dst->used = now; @@ -176,7 +181,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb }
if (local_rcv) - return br_pass_frame_up(skb); + return br_pass_frame_up(skb, promisc);
out: return 0; @@ -336,6 +341,8 @@ static rx_handler_result_t br_handle_frame(struct sk_buff **pskb) goto forward; }
+ BR_INPUT_SKB_CB(skb)->promisc = false; + /* The else clause should be hit when nf_hook(): * - returns < 0 (drop/error) * - returns = 0 (stolen/nf_queue) diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c index 34c39464ae21..119b1a36a126 100644 --- a/net/bridge/br_netfilter_hooks.c +++ b/net/bridge/br_netfilter_hooks.c @@ -598,11 +598,17 @@ static unsigned int br_nf_local_in(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { + bool promisc = BR_INPUT_SKB_CB(skb)->promisc; struct nf_conntrack *nfct = skb_nfct(skb); const struct nf_ct_hook *ct_hook; struct nf_conn *ct; int ret;
+ if (promisc) { + nf_reset_ct(skb); + return NF_ACCEPT; + } + if (!nfct || skb->pkt_type == PACKET_HOST) return NF_ACCEPT;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index bfd0e995b078..ca2d2e0b622e 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -497,6 +497,7 @@ struct br_input_skb_cb { #endif u8 proxyarp_replied:1; u8 src_port_isolated:1; + u8 promisc:1; #ifdef CONFIG_BRIDGE_VLAN_FILTERING u8 vlan_filtered:1; #endif diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c index 83743e95939b..fbdb1ad448c3 100644 --- a/net/bridge/netfilter/nf_conntrack_bridge.c +++ b/net/bridge/netfilter/nf_conntrack_bridge.c @@ -293,18 +293,24 @@ static unsigned int nf_ct_bridge_pre(void *priv, struct sk_buff *skb, static unsigned int nf_ct_bridge_in(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { - enum ip_conntrack_info ctinfo; + bool promisc = BR_INPUT_SKB_CB(skb)->promisc; + struct nf_conntrack *nfct = skb_nfct(skb); struct nf_conn *ct;
- if (skb->pkt_type == PACKET_HOST) + if (promisc) { + nf_reset_ct(skb); + return NF_ACCEPT; + } + + if (!nfct || skb->pkt_type == PACKET_HOST) return NF_ACCEPT;
/* nf_conntrack_confirm() cannot handle concurrent clones, * this happens for broad/multicast frames with e.g. macvlan on top * of the bridge device. */ - ct = nf_ct_get(skb, &ctinfo); - if (!ct || nf_ct_is_confirmed(ct) || nf_ct_is_template(ct)) + ct = container_of(nfct, struct nf_conn, ct_general); + if (nf_ct_is_confirmed(ct) || nf_ct_is_template(ct)) return NF_ACCEPT;
/* let inet prerouting call conntrack again */