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LinuxCVE-2022-48910

HistoryAug 22, 2024 - 2:15 a.m.

CVE-2022-48910

2024-08-2202:15:05

Linux

web.nvd.nist.gov

linux kernel

net ipv6

vulnerability

resolved

multicast group

idev_mc_tomb

sysctl

network interface

ipv6 state

addrconf_notify

ipv6_disabled

ipv6_mc_down

ipv6_mc_up

CVSS3

5.5

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

AI Score

6.6

Confidence

High

EPSS

Percentile

5.1%

JSON

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

net: ipv6: ensure we call ipv6_mc_down() at most once

There are two reasons for addrconf_notify() to be called with NETDEV_DOWN:
either the network device is actually going down, or IPv6 was disabled
on the interface.

If either of them stays down while the other is toggled, we repeatedly
call the code for NETDEV_DOWN, including ipv6_mc_down(), while never
calling the corresponding ipv6_mc_up() in between. This will cause a
new entry in idev->mc_tomb to be allocated for each multicast group
the interface is subscribed to, which in turn leaks one struct ifmcaddr6
per nontrivial multicast group the interface is subscribed to.

The following reproducer will leak at least $n objects:

ip addr add ff2e::4242/32 dev eth0 autojoin
sysctl -w net.ipv6.conf.eth0.disable_ipv6=1
for i in $(seq 1 $n); do
ip link set up eth0; ip link set down eth0
done

Joining groups with IPV6_ADD_MEMBERSHIP (unprivileged) or setting the
sysctl net.ipv6.conf.eth0.forwarding to 1 (=> subscribing to ff02::2)
can also be used to create a nontrivial idev->mc_list, which will the
leak objects with the right up-down-sequence.

Based on both sources for NETDEV_DOWN events the interface IPv6 state
should be considered:

not ready if the network interface is not ready OR IPv6 is disabled
for it
ready if the network interface is ready AND IPv6 is enabled for it

The functions ipv6_mc_up() and ipv6_down() should only be run when this
state changes.

Implement this by remembering when the IPv6 state is ready, and only
run ipv6_mc_down() if it actually changed from ready to not ready.

The other direction (not ready -> ready) already works correctly, as:

the interface notification triggered codepath for NETDEV_UP /
NETDEV_CHANGE returns early if ipv6 is disabled, and
the disable_ipv6=0 triggered codepath skips fully initializing the
interface as long as addrconf_link_ready(dev) returns false
calling ipv6_mc_up() repeatedly does not leak anything

Affected configurations

Nvd

Vulners

Node

linuxlinux_kernelRange3.18–4.9.313

linuxlinux_kernelRange4.10–4.14.278

linuxlinux_kernelRange4.15–5.4.193

linuxlinux_kernelRange5.5–5.10.104

linuxlinux_kernelRange5.11–5.15.27

linuxlinux_kernelRange5.16–5.16.13

linuxlinux_kernelMatch5.17rc1

linuxlinux_kernelMatch5.17rc2

linuxlinux_kernelMatch5.17rc3

linuxlinux_kernelMatch5.17rc4

linuxlinux_kernelMatch5.17rc5

linuxlinux_kernelMatch5.17rc6

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel5.17cpe:2.3:o:linux:linux_kernel:5.17:rc1:*:*:*:*:*:*
linuxlinux_kernel5.17cpe:2.3:o:linux:linux_kernel:5.17:rc2:*:*:*:*:*:*
linuxlinux_kernel5.17cpe:2.3:o:linux:linux_kernel:5.17:rc3:*:*:*:*:*:*
linuxlinux_kernel5.17cpe:2.3:o:linux:linux_kernel:5.17:rc4:*:*:*:*:*:*
linuxlinux_kernel5.17cpe:2.3:o:linux:linux_kernel:5.17:rc5:*:*:*:*:*:*
linuxlinux_kernel5.17cpe:2.3:o:linux:linux_kernel:5.17:rc6:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.17	cpe:2.3:o:linux:linux_kernel:5.17:rc1::::::
linux	linux_kernel	5.17	cpe:2.3:o:linux:linux_kernel:5.17:rc2::::::
linux	linux_kernel	5.17	cpe:2.3:o:linux:linux_kernel:5.17:rc3::::::
linux	linux_kernel	5.17	cpe:2.3:o:linux:linux_kernel:5.17:rc4::::::
linux	linux_kernel	5.17	cpe:2.3:o:linux:linux_kernel:5.17:rc5::::::
linux	linux_kernel	5.17	cpe:2.3:o:linux:linux_kernel:5.17:rc6::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/addrconf.c"
    ],
    "versions": [
      {
        "version": "3ce62a84d53c",
        "lessThan": "9a8736b2da28",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3ce62a84d53c",
        "lessThan": "c71bf3229f9e",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3ce62a84d53c",
        "lessThan": "9588ac2eddc2",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3ce62a84d53c",
        "lessThan": "f4c63b24dea9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3ce62a84d53c",
        "lessThan": "b11781515208",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3ce62a84d53c",
        "lessThan": "72124e65a70b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "3ce62a84d53c",
        "lessThan": "9995b408f17f",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ipv6/addrconf.c"
    ],
    "versions": [
      {
        "version": "3.18",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "3.18",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.9.313",
        "lessThanOrEqual": "4.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "4.14.278",
        "lessThanOrEqual": "4.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.193",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.104",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.27",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16.13",
        "lessThanOrEqual": "5.16.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.17",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]