CVE-2021-47309 net: validate lwtstate->data before returning from skb_tunnel_info()

2024-05-2114:35:27

Linux

github.com

cve-2021-47309

net

lwtstate

skb_tunnel_info

linux kernel

vulnerability

resolved

splat

bug

kasan

slab-out-of-bounds

vxlan_get_route

ping

cpu

pid

comm

6.8 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

13.1%

JSON

In the Linux kernel, the following vulnerability has been resolved:

net: validate lwtstate->data before returning from skb_tunnel_info()

skb_tunnel_info() returns pointer of lwtstate->data as ip_tunnel_info
type without validation. lwtstate->data can have various types such as
mpls_iptunnel_encap, etc and these are not compatible.
So skb_tunnel_info() should validate before returning that pointer.

Splat looks like:
BUG: KASAN: slab-out-of-bounds in vxlan_get_route+0x418/0x4b0 [vxlan]
Read of size 2 at addr ffff888106ec2698 by task ping/811

CPU: 1 PID: 811 Comm: ping Not tainted 5.13.0+ #1195
Call Trace:
dump_stack_lvl+0x56/0x7b
print_address_description.constprop.8.cold.13+0x13/0x2ee
? vxlan_get_route+0x418/0x4b0 [vxlan]
? vxlan_get_route+0x418/0x4b0 [vxlan]
kasan_report.cold.14+0x83/0xdf
? vxlan_get_route+0x418/0x4b0 [vxlan]
vxlan_get_route+0x418/0x4b0 [vxlan]
[ … ]
vxlan_xmit_one+0x148b/0x32b0 [vxlan]
[ … ]
vxlan_xmit+0x25c5/0x4780 [vxlan]
[ … ]
dev_hard_start_xmit+0x1ae/0x6e0
__dev_queue_xmit+0x1f39/0x31a0
[ … ]
neigh_xmit+0x2f9/0x940
mpls_xmit+0x911/0x1600 [mpls_iptunnel]
lwtunnel_xmit+0x18f/0x450
ip_finish_output2+0x867/0x2040
[ … ]

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/net/dst_metadata.h"
    ],
    "versions": [
      {
        "version": "61adedf3e3f1",
        "lessThan": "e7f3c9df4051",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "b61d327cd3cc",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "83bdcfbd968b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "8bb1589c89e6",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "8aa13a86964c",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "2179d96ec702",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "a915379594f1",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "61adedf3e3f1",
        "lessThan": "67a9c9431740",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/net/dst_metadata.h"
    ],
    "versions": [
      {
        "version": "4.3",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.3",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.4.277",
        "lessThanOrEqual": "4.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.277",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.241",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.19.199",
        "lessThanOrEqual": "4.19.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.135",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.53",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.13.5",
        "lessThanOrEqual": "5.13.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.14",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]