CVE-2021-47309

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: validate lwtstate-&gt;data before returning from skb_tunnel_info()<br /> <br /> skb_tunnel_info() returns pointer of lwtstate-&gt;data as ip_tunnel_info<br /> type without validation. lwtstate-&gt;data can have various types such as<br /> mpls_iptunnel_encap, etc and these are not compatible.<br /> So skb_tunnel_info() should validate before returning that pointer.<br /> <br /> Splat looks like:<br /> BUG: KASAN: slab-out-of-bounds in vxlan_get_route+0x418/0x4b0 [vxlan]<br /> Read of size 2 at addr ffff888106ec2698 by task ping/811<br /> <br /> CPU: 1 PID: 811 Comm: ping Not tainted 5.13.0+ #1195<br /> Call Trace:<br /> dump_stack_lvl+0x56/0x7b<br /> print_address_description.constprop.8.cold.13+0x13/0x2ee<br /> ? vxlan_get_route+0x418/0x4b0 [vxlan]<br /> ? vxlan_get_route+0x418/0x4b0 [vxlan]<br /> kasan_report.cold.14+0x83/0xdf<br /> ? vxlan_get_route+0x418/0x4b0 [vxlan]<br /> vxlan_get_route+0x418/0x4b0 [vxlan]<br /> [ ... ]<br /> vxlan_xmit_one+0x148b/0x32b0 [vxlan]<br /> [ ... ]<br /> vxlan_xmit+0x25c5/0x4780 [vxlan]<br /> [ ... ]<br /> dev_hard_start_xmit+0x1ae/0x6e0<br /> __dev_queue_xmit+0x1f39/0x31a0<br /> [ ... ]<br /> neigh_xmit+0x2f9/0x940<br /> mpls_xmit+0x911/0x1600 [mpls_iptunnel]<br /> lwtunnel_xmit+0x18f/0x450<br /> ip_finish_output2+0x867/0x2040<br /> [ ... ]