CVE-2024-50045

CVE Details

Release Date:

2024-10-21

Description

In the Linux kernel, the following vulnerability has been resolved:\nnetfilter: br_netfilter: fix panic with metadata_dst skb\nFix a kernel panic in the br_netfilter module when sending untagged\ntraffic via a VxLAN device.\nThis happens during the check for fragmentation in br_nf_dev_queue_xmit.\nIt is dependent on:\n1) the br_netfilter module being loaded;\n2) net.bridge.bridge-nf-call-iptables set to 1;\n3) a bridge with a VxLAN (single-vxlan-device) netdevice as a bridge port;\n4) untagged frames with size higher than the VxLAN MTU forwarded/flooded\nWhen forwarding the untagged packet to the VxLAN bridge port, before\nthe netfilter hooks are called, br_handle_egress_vlan_tunnel is called and\nchanges the skb_dst to the tunnel dst. The tunnel_dst is a metadata type\nof dst, i.e., skb_valid_dst(skb) is false, and metadata->dst.dev is NULL.\nThen in the br_netfilter hooks, in br_nf_dev_queue_xmit, there's a check\nfor frames that needs to be fragmented: frames with higher MTU than the\nVxLAN device end up calling br_nf_ip_fragment, which in turns call\nip_skb_dst_mtu.\nThe ip_dst_mtu tries to use the skb_dst(skb) as if it was a valid dst\nwith valid dst->dev, thus the crash.\nThis case was never supported in the first place, so drop the packet\ninstead.\nPING 10.0.0.2 (10.0.0.2) from 0.0.0.0 h1-eth0: 2000(2028) bytes of data.\n[ 176.291791] Unable to handle kernel NULL pointer dereference at\nvirtual address 0000000000000110\n[ 176.292101] Mem abort info:\n[ 176.292184] ESR = 0x0000000096000004\n[ 176.292322] EC = 0x25: DABT (current EL), IL = 32 bits\n[ 176.292530] SET = 0, FnV = 0\n[ 176.292709] EA = 0, S1PTW = 0\n[ 176.292862] FSC = 0x04: level 0 translation fault\n[ 176.293013] Data abort info:\n[ 176.293104] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000\n[ 176.293488] CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n[ 176.293787] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n[ 176.293995] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000043ef5000\n[ 176.294166] [0000000000000110] pgd=0000000000000000,\np4d=0000000000000000\n[ 176.294827] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP\n[ 176.295252] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel veth\nbr_netfilter bridge stp llc ipv6 crct10dif_ce\n[ 176.295923] CPU: 0 PID: 188 Comm: ping Not tainted\n6.8.0-rc3-g5b3fbd61b9d1 #2\n[ 176.296314] Hardware name: linux,dummy-virt (DT)\n[ 176.296535] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS\nBTYPE=--)\n[ 176.296808] pc : br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter]\n[ 176.297382] lr : br_nf_dev_queue_xmit+0x2ac/0x4ec [br_netfilter]\n[ 176.297636] sp : ffff800080003630\n[ 176.297743] x29: ffff800080003630 x28: 0000000000000008 x27:\nffff6828c49ad9f8\n[ 176.298093] x26: ffff6828c49ad000 x25: 0000000000000000 x24:\n00000000000003e8\n[ 176.298430] x23: 0000000000000000 x22: ffff6828c4960b40 x21:\nffff6828c3b16d28\n[ 176.298652] x20: ffff6828c3167048 x19: ffff6828c3b16d00 x18:\n0000000000000014\n[ 176.298926] x17: ffffb0476322f000 x16: ffffb7e164023730 x15:\n0000000095744632\n[ 176.299296] x14: ffff6828c3f1c880 x13: 0000000000000002 x12:\nffffb7e137926a70\n[ 176.299574] x11: 0000000000000001 x10: ffff6828c3f1c898 x9 :\n0000000000000000\n[ 176.300049] x8 : ffff6828c49bf070 x7 : 0008460f18d5f20e x6 :\nf20e0100bebafeca\n[ 176.300302] x5 : ffff6828c7f918fe x4 : ffff6828c49bf070 x3 :\n0000000000000000\n[ 176.300586] x2 : 0000000000000000 x1 : ffff6828c3c7ad00 x0 :\nffff6828c7f918f0\n[ 176.300889] Call trace:\n[ 176.301123] br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter]\n[ 176.301411] br_nf_post_routing+0x2a8/0x3e4 [br_netfilter]\n[ 176.301703] nf_hook_slow+0x48/0x124\n[ 176.302060] br_forward_finish+0xc8/0xe8 [bridge]\n[ 176.302371] br_nf_hook_thresh+0x124/0x134 [br_netfilter]\n[ 176.302605] br_nf_forward_finish+0x118/0x22c [br_netfilter]\n[ 176.302824] br_nf_forward_ip.part.0+0x264/0x290 [br_netfilter]\n[ 176.303136] br_nf_forward+0x2b8/0x4e0 [br_netfilter]\n[ 176.303359] nf_hook_slow+0x48/0x124\n[ 176.303\n---truncated---

See more information about CVE-2024-50045 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality:	None
Integrity:	None
Availability:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12884	2024-12-16
Oracle Linux version 8 (kernel-uek)	ELSA-2024-12884	2024-12-16
Oracle Linux version 8 (kernel-uek)	ELSA-2024-12887	2024-12-18
Oracle Linux version 9 (kernel-uek)	ELSA-2024-12887	2024-12-18