RHSA-2021:4513 - Security Advisory

Topic

An update for libsepol is now available for Red Hat Enterprise Linux 8.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The libsepol library provides an API for the manipulation of SELinux binary policies. It is used by checkpolicy (the policy compiler) and similar tools, as well as by programs like load_policy that need to perform specific transformations on binary policies (for example, customizing policy boolean settings).

Security Fix(es):

• libsepol: use-after-free in __cil_verify_classperms() (CVE-2021-36084)
• libsepol: use-after-free in __cil_verify_classperms() (CVE-2021-36085)
• libsepol: use-after-free in cil_reset_classpermission() (CVE-2021-36086)
• libsepol: heap-based buffer overflow in ebitmap_match_any() (CVE-2021-36087)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.5 Release Notes linked from the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 8 x86_64
• Red Hat Enterprise Linux for IBM z Systems 8 s390x
• Red Hat Enterprise Linux for Power, little endian 8 ppc64le
• Red Hat Enterprise Linux for ARM 64 8 aarch64
• Red Hat CodeReady Linux Builder for x86_64 8 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian 8 ppc64le
• Red Hat CodeReady Linux Builder for ARM 64 8 aarch64
• Red Hat CodeReady Linux Builder for IBM z Systems 8 s390x

Fixes

• BZ - 1979662 - CVE-2021-36084 libsepol: use-after-free in __cil_verify_classperms()
• BZ - 1979664 - CVE-2021-36085 libsepol: use-after-free in __cil_verify_classperms()
• BZ - 1979666 - CVE-2021-36086 libsepol: use-after-free in cil_reset_classpermission()
• BZ - 1979668 - CVE-2021-36087 libsepol: heap-based buffer overflow in ebitmap_match_any()

CVEs

• CVE-2021-36084
• CVE-2021-36085
• CVE-2021-36086
• CVE-2021-36087

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.5_release_notes/