UBUNTU-CVE-2021-47146: Medium severity ubuntu/linux-azure vulnerability

Q: Who is realistically exposed to this issue?

Systems running one of the listed Ubuntu kernel packages are potentially affected when IPv6 multicast listener discovery traffic is used with a network configuration that creates excessive headroom, such as the demonstrated large set of IPv6 GRE tunnels.

Q: What level of access does an attacker need?

The supplied severity vector indicates local access with low privileges and no user interaction. The proof-of-concept configuration uses network namespaces and creates/configures veth and IPv6 GRE interfaces.

Q: What is the practical impact of successful exploitation?

The documented failure is a kernel panic in skb_put(), resulting in a denial of service through system crash or interruption of kernel networking.

Q: How can administrators determine whether they are affected?

Review whether the host runs a listed Ubuntu kernel package and permits low-privileged users or workloads to create network namespaces and configure large numbers of IPv6 GRE tunnels. Kernel logs showing a BUG at net/core/skbuff.c:110 during this type of networking activity are consistent with the reported failure.

Published Mar 25, 2024

Updated

In the Linux kernel, the following vulnerability has been resolved: mld: fix panic in mldnewpack() mldnewpack() doesn't allow to allocate high order page, only order-0 allocation is allowed. If headroom size is too large, a kernel panic could occur in skbput(). Test commands: ip netns del A ip netns del B ip netns add A ip netns add B ip link add veth0 type veth peer name veth1 ip link set veth0 netns A ip link set veth1 netns B ip netns exec A ip link set lo up ip netns exec A ip link set veth0 up ip netns exec A ip -6 a a 2001:db8:0::1/64 dev veth0 ip netns exec B ip link set lo up ip netns exec B ip link set veth1 up ip netns exec B ip -6 a a 2001:db8:0::2/64 dev veth1 for i in {1..99} do let A=$i-1 ip netns exec A ip link add ip6gre$i type ip6gre \ local 2001:db8:$A::1 remote 2001:db8:$A::2 encaplimit 100 ip netns exec A ip -6 a a 2001:db8:$i::1/64 dev ip6gre$i ip netns exec A ip link set ip6gre$i up ip netns exec B ip link add ip6gre$i type ip6gre \ local 2001:db8:$A::2 remote 2001:db8:$A::1 encaplimit 100 ip netns exec B ip -6 a a 2001:db8:$i::2/64 dev ip6gre$i ip netns exec B ip link set ip6gre$i up done Splat looks like: kernel BUG at net/core/skbuff.c:110! invalid opcode: 0000 [#1] SMP DEBUGPAGEALLOC KASAN PTI CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.12.0+ #891 Workqueue: ipv6addrconf addrconfdadwork RIP: 0010:skbpanic+0x15d/0x15f Code: 92 fe 4c 8b 4c 24 10 53 8b 4d 70 45 89 e0 48 c7 c7 00 ae 79 83 41 57 41 56 41 55 48 8b 54 24 a6 26 f9 ff <0f> 0b 48 8b 6c 24 20 89 34 24 e8 4a 4e 92 fe 8b 34 24 48 c7 c1 20 RSP: 0018:ffff88810091f820 EFLAGS: 00010282 RAX: 0000000000000089 RBX: ffff8881086e9000 RCX: 0000000000000000 RDX: 0000000000000089 RSI: 0000000000000008 RDI: ffffed1020123efb RBP: ffff888005f6eac0 R08: ffffed1022fc0031 R09: ffffed1022fc0031 R10: ffff888117e00187 R11: ffffed1022fc0030 R12: 0000000000000028 R13: ffff888008284eb0 R14: 0000000000000ed8 R15: 0000000000000ec0 FS: 0000000000000000(0000) GS:ffff888117c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8b801c5640 CR3: 0000000033c2c006 CR4: 00000000003706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? ip6mchdr.isra.26.constprop.46+0x12a/0x600 ? ip6mchdr.isra.26.constprop.46+0x12a/0x600 skbput.cold.104+0x22/0x22 ip6mchdr.isra.26.constprop.46+0x12a/0x600 ? rcureadlockschedheld+0x91/0xc0 mldnewpack+0x398/0x8f0 ? ip6mchdr.isra.26.constprop.46+0x600/0x600 ? lockcontended+0xc40/0xc40 addgrhead.isra.33+0x280/0x380 addgrec+0x5ca/0xff0 ? mldsendpack+0xf40/0xf40 ? lockdowngrade+0x690/0x690 mldsendinitialcr.part.34+0xb9/0x180 ipv6mcdadcomplete+0x15d/0x1b0 addrconfdadcompleted+0x8d2/0xbb0 ? lockdowngrade+0x690/0x690 ? addrconfrstimer+0x660/0x660 ? addrconfdadwork+0x73c/0x10e0 addrconfdadwork+0x73c/0x10e0 Allowing high order page allocation could fix this problem.

Affected Software

118 affected componentsFixes available

ubuntu/linux-azure<4.15.0-1121.134~14.04.1

4.15.0-1121.134~14.04.1

ubuntu/linux*

ubuntu/linux-aws<4.4.0-1150.156

4.4.0-1150.156

ubuntu/linux-lts-xenial<4.4.0-276.310~14.04.1

4.4.0-276.310~14.04.1

ubuntu/linux<4.4.0-276.310

4.4.0-276.310

ubuntu/linux-aws<4.4.0-1188.203

4.4.0-1188.203

ubuntu/linux-aws-hwe<4.15.0-1109.116~16.04.1

4.15.0-1109.116~16.04.1

ubuntu/linux-azure<4.15.0-1121.134~16.04.1

4.15.0-1121.134~16.04.1

ubuntu/linux-gcp<4.15.0-1106.120~16.04.1

4.15.0-1106.120~16.04.1

ubuntu/linux-hwe<4.15.0-151.157~16.04.1

4.15.0-151.157~16.04.1

ubuntu/linux-kvm<4.4.0-1151.162

4.4.0-1151.162

ubuntu/linux-oracle<4.15.0-1078.86~16.04.1

4.15.0-1078.86~16.04.1

ubuntu/linux-hwe-edge*

ubuntu/linux-fips<4.4.0-1120.127

4.4.0-1120.127

ubuntu/linux-fips*

ubuntu/linux<4.15.0-151.157

4.15.0-151.157

ubuntu/linux-aws<4.15.0-1109.116

4.15.0-1109.116

ubuntu/linux-aws-5.4<5.4.0-1054.57~18.04.1

5.4.0-1054.57~18.04.1

ubuntu/linux-azure-4.15<4.15.0-1121.134

4.15.0-1121.134

ubuntu/linux-azure-5.4<5.4.0-1055.57~18.04.1

5.4.0-1055.57~18.04.1

ubuntu/linux-gcp-4.15<4.15.0-1106.120

4.15.0-1106.120

ubuntu/linux-gcp-5.4<5.4.0-1049.53~18.04.1

5.4.0-1049.53~18.04.1

ubuntu/linux-hwe-5.4<5.4.0-80.90~18.04.1

5.4.0-80.90~18.04.1

ubuntu/linux-kvm<4.15.0-1097.99

4.15.0-1097.99

ubuntu/linux-oracle<4.15.0-1078.86

4.15.0-1078.86

ubuntu/linux-oracle-5.4<5.4.0-1052.56~18.04.1

5.4.0-1052.56~18.04.1

ubuntu/linux-raspi-5.4<5.4.0-1041.45~18.04.1

5.4.0-1041.45~18.04.1

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-fips<4.15.0-2051.53

4.15.0-2051.53

ubuntu/linux-azure-fips<4.15.0-2033.37

4.15.0-2033.37

ubuntu/linux-fips<4.15.0-1066.75

4.15.0-1066.75

ubuntu/linux-gcp-fips<4.15.0-2016.18

4.15.0-2016.18

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.4.0-80.90

5.4.0-80.90

ubuntu/linux-aws<5.4.0-1054.57

5.4.0-1054.57

ubuntu/linux-azure<5.4.0-1055.57

5.4.0-1055.57

ubuntu/linux-bluefield<5.4.0-1016.19

5.4.0-1016.19

ubuntu/linux-gcp<5.4.0-1049.53

5.4.0-1049.53

ubuntu/linux-gkeop<5.4.0-1021.22

5.4.0-1021.22

ubuntu/linux-kvm<5.4.0-1044.46

5.4.0-1044.46

ubuntu/linux-oracle<5.4.0-1052.56

5.4.0-1052.56

ubuntu/linux-raspi<5.4.0-1041.45

5.4.0-1041.45

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.8*

ubuntu/linux-intel-5.13*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-aws-fips<5.4.0-1069.73+fips2

5.4.0-1069.73+fips2

ubuntu/linux-azure-fips<5.4.0-1073.76+fips1

5.4.0-1073.76+fips1

ubuntu/linux-fips<5.4.0-1031.36

5.4.0-1031.36

ubuntu/linux-gcp-fips<5.4.0-1067.71~20.04.1

5.4.0-1067.71~20.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-raspi-realtime*

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 4.15.0-1121.134~14.04.1
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1150.156
Upgrade
Upgrade ubuntu/linux-lts-xenial to a version that resolves this vulnerability.
Fixed in 4.4.0-276.310~14.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.4.0-276.310
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1188.203
Upgrade
Upgrade ubuntu/linux-aws-hwe to a version that resolves this vulnerability.
Fixed in 4.15.0-1109.116~16.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 4.15.0-1121.134~16.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 4.15.0-1106.120~16.04.1
Upgrade
Upgrade ubuntu/linux-hwe to a version that resolves this vulnerability.
Fixed in 4.15.0-151.157~16.04.1
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.4.0-1151.162
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1078.86~16.04.1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.4.0-1120.127
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.15.0-151.157
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.15.0-1109.116
Upgrade
Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1054.57~18.04.1
Upgrade
Upgrade ubuntu/linux-azure-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1121.134
Upgrade
Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1055.57~18.04.1
Upgrade
Upgrade ubuntu/linux-gcp-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1106.120
Upgrade
Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1049.53~18.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-80.90~18.04.1
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.15.0-1097.99
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1078.86
Upgrade
Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1052.56~18.04.1
Upgrade
Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1041.45~18.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2051.53
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2033.37
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-1066.75
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2016.18
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.4.0-80.90
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.4.0-1054.57
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.4.0-1055.57
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.4.0-1016.19
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.4.0-1049.53
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.4.0-1021.22
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.4.0-1044.46
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.4.0-1052.56
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 5.4.0-1041.45
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1069.73+fips2
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1073.76+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1031.36
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1067.71~20.04.1
Compensating control
Modify mld_newpack() to allow high-order page allocation, which could prevent the skb_put() kernel panic caused by excessive headroom.

Event History

Mar 25, 2024

CVE Published

via OSV·09:15 AM

Data Sourced

via OSV·09:15 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

Who is realistically exposed to this issue?

Systems running one of the listed Ubuntu kernel packages are potentially affected when IPv6 multicast listener discovery traffic is used with a network configuration that creates excessive headroom, such as the demonstrated large set of IPv6 GRE tunnels.

What level of access does an attacker need?

The supplied severity vector indicates local access with low privileges and no user interaction. The proof-of-concept configuration uses network namespaces and creates/configures veth and IPv6 GRE interfaces.

What is the practical impact of successful exploitation?

The documented failure is a kernel panic in skb_put(), resulting in a denial of service through system crash or interruption of kernel networking.

How can administrators determine whether they are affected?

Review whether the host runs a listed Ubuntu kernel package and permits low-privileged users or workloads to create network namespaces and configure large numbers of IPv6 GRE tunnels. Kernel logs showing a BUG at net/core/skbuff.c:110 during this type of networking activity are consistent with the reported failure.

UBUNTU-CVE-2021-47146: Medium severity ubuntu/linux-azure vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Who is realistically exposed to this issue?

What level of access does an attacker need?

What is the practical impact of successful exploitation?

How can administrators determine whether they are affected?

Company

Resources

Contact

Frequently Asked Questions

Who is realistically exposed to this issue?

What level of access does an attacker need?

What is the practical impact of successful exploitation?

How can administrators determine whether they are affected?