A flaw was found in the Linux kernel SELinux LSM hook implementation before version 5.7, where it incorrectly assumed that an skb would only contain a single netlink message. The hook would incorrectly only validate the first netlink message in the skb and allow or deny the rest of the messages within the skb with the granted permission without further processing. At this time, there is no known ability for an attacker to use this to abuse this flaw as capabilities are required to process any 'modify' operation.
External References: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fb73974172ffaaf57a7c42f35424d9aece1a5af6 https://www.openwall.com/lists/oss-security/2020/04/30/5 https://lore.kernel.org/selinux/CACT4Y+b8HiV6KFuAPysZD=5hmyO4QisgxCKi4DHU3CfMPSP=yg@mail.gmail.com/
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1844353]
Mitigation: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
This was fixed for Fedora with the 5.6.11 stable kernel updates.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2020:4062 https://access.redhat.com/errata/RHSA-2020:4062
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2020:4060 https://access.redhat.com/errata/RHSA-2020:4060
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2020-10751
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:4431 https://access.redhat.com/errata/RHSA-2020:4431
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:4609 https://access.redhat.com/errata/RHSA-2020:4609