CVE Vulnerabilities

CVE-2018-20854

Out-of-bounds Read

Published: Jul 26, 2019 | Modified: Nov 21, 2024
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
4.6 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
4.7 MODERATE
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Ubuntu
LOW

An issue was discovered in the Linux kernel before 4.20. drivers/phy/mscc/phy-ocelot-serdes.c has an off-by-one error with a resultant ctrl->phys out-of-bounds read.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name Vendor Start Version End Version
Linux_kernel Linux * 4.20 (excluding)
Linux Ubuntu trusty *
Linux-aws Ubuntu trusty *
Linux-aws Ubuntu upstream *
Linux-aws-hwe Ubuntu upstream *
Linux-azure Ubuntu trusty *
Linux-azure Ubuntu upstream *
Linux-azure-edge Ubuntu upstream *
Linux-euclid Ubuntu esm-apps/xenial *
Linux-euclid Ubuntu upstream *
Linux-euclid Ubuntu xenial *
Linux-flo Ubuntu esm-apps/xenial *
Linux-flo Ubuntu trusty *
Linux-flo Ubuntu upstream *
Linux-flo Ubuntu xenial *
Linux-gcp Ubuntu upstream *
Linux-gcp-edge Ubuntu upstream *
Linux-gke Ubuntu upstream *
Linux-gke Ubuntu xenial *
Linux-gke-4.15 Ubuntu upstream *
Linux-goldfish Ubuntu esm-apps/xenial *
Linux-goldfish Ubuntu trusty *
Linux-goldfish Ubuntu upstream *
Linux-goldfish Ubuntu xenial *
Linux-grouper Ubuntu trusty *
Linux-grouper Ubuntu upstream *
Linux-hwe Ubuntu upstream *
Linux-hwe-edge Ubuntu upstream *
Linux-kvm Ubuntu upstream *
Linux-lts-trusty Ubuntu upstream *
Linux-lts-utopic Ubuntu trusty *
Linux-lts-utopic Ubuntu upstream *
Linux-lts-vivid Ubuntu trusty *
Linux-lts-vivid Ubuntu upstream *
Linux-lts-wily Ubuntu trusty *
Linux-lts-wily Ubuntu upstream *
Linux-lts-xenial Ubuntu trusty *
Linux-lts-xenial Ubuntu upstream *
Linux-maguro Ubuntu trusty *
Linux-maguro Ubuntu upstream *
Linux-mako Ubuntu esm-apps/xenial *
Linux-mako Ubuntu trusty *
Linux-mako Ubuntu upstream *
Linux-mako Ubuntu xenial *
Linux-manta Ubuntu trusty *
Linux-manta Ubuntu upstream *
Linux-oem Ubuntu upstream *
Linux-oem Ubuntu xenial *
Linux-oracle Ubuntu upstream *
Linux-raspi2 Ubuntu upstream *
Linux-snapdragon Ubuntu upstream *

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

References