Heap-based buffer overflow in Linux kernel - CVE-2021-20194

Vulnerability identifier: #VU60356

CSH Severity: Low

CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-20194

CWE-ID: CWE-122

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error within the __cgroup_bpf_run_filter_getsockopt() function, when kernel is compiled with config params CONFIG_BPF_SYSCALL=y , CONFIG_BPF=y , CONFIG_CGROUPS=y , CONFIG_CGROUP_BPF=y , CONFIG_HARDENED_USERCOPY not set, and BPF hook to getsockopt is registered. A local user can trigger a heap-based buffer overflow and execute arbitrary code with elevated privileges.

Linux kernel
Red Hat Enterprise Linux for Real Time
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for Real Time for NFV
Ubuntu
Fedora
Traffix SDC
kernel (Red Hat package)
kernel-rt (Red Hat package)
linux-image-generic (Ubuntu package)
linux-image-generic-lpae (Ubuntu package)
linux-image-lowlatency (Ubuntu package)
linux-image-oem (Ubuntu package)
linux-image-oem-osp1 (Ubuntu package)
linux-image-virtual (Ubuntu package)
linux-image-5.4.0-71-generic (Ubuntu package)
linux-image-5.4.0-71-generic-lpae (Ubuntu package)
linux-image-5.4.0-71-lowlatency (Ubuntu package)
linux-image-virtual-hwe-18.04 (Ubuntu package)
linux-image-lowlatency-hwe-18.04 (Ubuntu package)
linux-image-snapdragon-hwe-18.04 (Ubuntu package)
linux-image-generic-lpae-hwe-18.04 (Ubuntu package)
linux-image-generic-hwe-18.04 (Ubuntu package)
linux-image-5.4.0-1013-gkeop (Ubuntu package)
linux-image-gkeop-5.4 (Ubuntu package)
linux-image-gkeop (Ubuntu package)
linux-image-raspi-hwe-18.04 (Ubuntu package)
linux-image-5.4.0-1033-raspi (Ubuntu package)
linux-image-raspi (Ubuntu package)
linux-image-raspi2 (Ubuntu package)
linux-image-kvm (Ubuntu package)
linux-image-5.4.0-1037-kvm (Ubuntu package)
linux-image-5.4.0-1040-gke (Ubuntu package)
linux-image-gke-5.4 (Ubuntu package)
linux-image-gcp (Ubuntu package)
linux-image-5.4.0-1041-gcp (Ubuntu package)
linux-image-oracle (Ubuntu package)
linux-image-5.4.0-1042-oracle (Ubuntu package)
linux-image-aws (Ubuntu package)
linux-image-5.4.0-1043-aws (Ubuntu package)
linux-image-azure (Ubuntu package)
linux-image-5.4.0-1044-azure (Ubuntu package)
linux-image-oem-20.04 (Ubuntu package)
linux-image-5.6.0-1053-oem (Ubuntu package)
linux-image-generic-64k (Ubuntu package)
linux-image-5.8.0-45-generic (Ubuntu package)
linux-image-5.8.0-45-generic-64k (Ubuntu package)
linux-image-5.8.0-45-generic-lpae (Ubuntu package)
linux-image-5.8.0-45-lowlatency (Ubuntu package)
linux-image-generic-64k-hwe-20.04 (Ubuntu package)
linux-image-generic-hwe-20.04 (Ubuntu package)
linux-image-generic-lpae-hwe-20.04 (Ubuntu package)
linux-image-lowlatency-hwe-20.04 (Ubuntu package)
linux-image-virtual-hwe-20.04 (Ubuntu package)
linux-image-raspi-nolpae (Ubuntu package)
linux-image-5.8.0-1017-raspi (Ubuntu package)
linux-image-5.8.0-1017-raspi-nolpae (Ubuntu package)
linux-image-5.8.0-1020-kvm (Ubuntu package)
linux-image-5.8.0-1022-oracle (Ubuntu package)
linux-image-gke (Ubuntu package)
linux-image-5.8.0-1024-gcp (Ubuntu package)
linux-image-5.8.0-1024-azure (Ubuntu package)
linux-image-5.8.0-1025-aws (Ubuntu package)
linux-image-5.10.0-1017-oem (Ubuntu package)
linux-image-oem-20.04b (Ubuntu package)
kernel

Install updates from vendor's website.

kernel (Red Hat package) - update to 4.18.0-348.el8
kernel-rt (Red Hat package) - update to 4.18.0-348.rt7.130.el8
linux-image-generic (Ubuntu package) - addressed in versions 5.4.0.71.74, 5.8.0.45.50
linux-image-generic-lpae (Ubuntu package) - addressed in versions 5.4.0.71.74, 5.8.0.45.50
linux-image-lowlatency (Ubuntu package) - addressed in versions 5.4.0.71.74, 5.8.0.45.50
linux-image-oem (Ubuntu package) - addressed in versions 5.4.0.71.74, 5.4.0.71.79~18.04.64
linux-image-oem-osp1 (Ubuntu package) - addressed in versions 5.4.0.71.74, 5.4.0.71.79~18.04.64
linux-image-virtual (Ubuntu package) - addressed in versions 5.4.0.71.74, 5.8.0.45.50
linux-image-5.4.0-71-generic (Ubuntu package) - addressed in versions 5.4.0-71.79, 5.4.0-71.79~18.04.1
linux-image-5.4.0-71-generic-lpae (Ubuntu package) - addressed in versions 5.4.0-71.79, 5.4.0-71.79~18.04.1
linux-image-5.4.0-71-lowlatency (Ubuntu package) - addressed in versions 5.4.0-71.79, 5.4.0-71.79~18.04.1
linux-image-virtual-hwe-18.04 (Ubuntu package) - update to 5.4.0.71.79~18.04.64
linux-image-lowlatency-hwe-18.04 (Ubuntu package) - update to 5.4.0.71.79~18.04.64
linux-image-snapdragon-hwe-18.04 (Ubuntu package) - update to 5.4.0.71.79~18.04.64
linux-image-generic-lpae-hwe-18.04 (Ubuntu package) - update to 5.4.0.71.79~18.04.64
linux-image-generic-hwe-18.04 (Ubuntu package) - update to 5.4.0.71.79~18.04.64
linux-image-5.4.0-1013-gkeop (Ubuntu package) - addressed in versions 5.4.0-1013.14, 5.4.0-1013.14~18.04.1
linux-image-gkeop-5.4 (Ubuntu package) - addressed in versions 5.4.0.1013.14~18.04.14, 5.4.0.1013.16
linux-image-gkeop (Ubuntu package) - update to 5.4.0.1013.16
linux-image-raspi-hwe-18.04 (Ubuntu package) - update to 5.4.0.1033.35
linux-image-5.4.0-1033-raspi (Ubuntu package) - addressed in versions 5.4.0-1033.36, 5.4.0-1033.36~18.04.1
linux-image-raspi (Ubuntu package) - addressed in versions 5.4.0.1033.68, 5.8.0.1017.20
linux-image-raspi2 (Ubuntu package) - update to 5.4.0.1033.68
linux-image-kvm (Ubuntu package) - addressed in versions 5.4.0.1037.35, 5.8.0.1020.22
linux-image-5.4.0-1037-kvm (Ubuntu package) - update to 5.4.0-1037.38
linux-image-5.4.0-1040-gke (Ubuntu package) - update to 5.4.0-1040.42~18.04.1
linux-image-gke-5.4 (Ubuntu package) - update to 5.4.0.1040.42~18.04.7
linux-image-gcp (Ubuntu package) - addressed in versions 5.4.0.1041.28, 5.4.0.1041.50, 5.8.0.1024.24
linux-image-5.4.0-1041-gcp (Ubuntu package) - addressed in versions 5.4.0-1041.44, 5.4.0-1041.44~18.04.1
linux-image-oracle (Ubuntu package) - addressed in versions 5.4.0.1042.39, 5.4.0.1042.45~18.04.24, 5.8.0.1022.21
linux-image-5.4.0-1042-oracle (Ubuntu package) - addressed in versions 5.4.0-1042.45, 5.4.0-1042.45~18.04.1
linux-image-aws (Ubuntu package) - addressed in versions 5.4.0.1043.26, 5.4.0.1043.44, 5.8.0.1025.27
linux-image-5.4.0-1043-aws (Ubuntu package) - addressed in versions 5.4.0-1043.45, 5.4.0-1043.45~18.04.1
linux-image-azure (Ubuntu package) - addressed in versions 5.4.0.1044.24, 5.4.0.1044.42, 5.8.0.1024.24
linux-image-5.4.0-1044-azure (Ubuntu package) - addressed in versions 5.4.0-1044.46, 5.4.0-1044.46~18.04.1
linux-image-oem-20.04 (Ubuntu package) - addressed in versions 5.6.0.1053.49, 5.8.0.45.50
linux-image-5.6.0-1053-oem (Ubuntu package) - update to 5.6.0-1053.57
linux-image-generic-64k (Ubuntu package) - update to 5.8.0.45.50
linux-image-5.8.0-45-generic (Ubuntu package) - update to 5.8.0-45.51~20.04.1
linux-image-5.8.0-45-generic-64k (Ubuntu package) - update to 5.8.0-45.51~20.04.1
linux-image-5.8.0-45-generic-lpae (Ubuntu package) - update to 5.8.0-45.51~20.04.1
linux-image-5.8.0-45-lowlatency (Ubuntu package) - update to 5.8.0-45.51~20.04.1
linux-image-generic-64k-hwe-20.04 (Ubuntu package) - update to 5.8.0.45.51~20.04.31
linux-image-generic-hwe-20.04 (Ubuntu package) - update to 5.8.0.45.51~20.04.31
linux-image-generic-lpae-hwe-20.04 (Ubuntu package) - update to 5.8.0.45.51~20.04.31
linux-image-lowlatency-hwe-20.04 (Ubuntu package) - update to 5.8.0.45.51~20.04.31
linux-image-virtual-hwe-20.04 (Ubuntu package) - update to 5.8.0.45.51~20.04.31
linux-image-raspi-nolpae (Ubuntu package) - update to 5.8.0.1017.20
linux-image-5.8.0-1017-raspi (Ubuntu package) - update to 5.8.0-1017.20
linux-image-5.8.0-1017-raspi-nolpae (Ubuntu package) - update to 5.8.0-1017.20
linux-image-5.8.0-1020-kvm (Ubuntu package) - update to 5.8.0-1020.22
linux-image-5.8.0-1022-oracle (Ubuntu package) - update to 5.8.0-1022.23
linux-image-gke (Ubuntu package) - update to 5.8.0.1024.24
linux-image-5.8.0-1024-gcp (Ubuntu package) - update to 5.8.0-1024.25
linux-image-5.8.0-1024-azure (Ubuntu package) - update to 5.8.0-1024.26
linux-image-5.8.0-1025-aws (Ubuntu package) - update to 5.8.0-1025.27
linux-image-5.10.0-1017-oem (Ubuntu package) - update to 5.10.0-1017.18
linux-image-oem-20.04b (Ubuntu package) - update to 5.10.0.1017.18
kernel - addressed in versions 5.10.15-100.fc32, 5.10.15-200.fc33

• https://bugzilla.redhat.com/show_bug.cgi?id=1912683
• https://security.netapp.com/advisory/ntap-20210326-0003/

• Privilege escalation in Linux kernel
• Privilege escalation in Traffix SDC
• Red Hat Enterprise Linux 8 update for kernel-rt
• Red Hat Enterprise Linux 8 update for kernel
• Ubuntu update for linux
• Ubuntu update for linux-oem-5.10
• Ubuntu update for linux
• Ubuntu update for linux-oem-5.6
• Fedora 33 update for kernel
• Fedora 32 update for kernel