In the Linux kernel, the following vulnerability has been resolved:
perf/core: Fix unconditional security_locked_down() call Currently, the
lockdown state is queried unconditionally, even though its result is used
only if the PERF_SAMPLE_REGS_INTR bit is set in attr.sample_type. While
that doesn’t matter in case of the Lockdown LSM, it causes trouble with the
SELinux’s lockdown hook implementation. SELinux implements the locked_down
hook with a check whether the current task’s type has the corresponding
“lockdown” class permission (“integrity” or “confidentiality”) allowed in
the policy. This means that calling the hook when the access control
decision would be ignored generates a bogus permission check and audit
record. Fix this by checking sample_type first and only calling the hook
when its result would be honored.
Author | Note |
---|---|
Priority reason: Only affects systems with SELinux configured, which is not the default on Ubuntu. |
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
ubuntu | 20.04 | noarch | linux | < 5.4.0-77.86 | UNKNOWN |
ubuntu | 20.04 | noarch | linux-aws | < 5.4.0-1051.53 | UNKNOWN |
ubuntu | 18.04 | noarch | linux-aws-5.4 | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-azure | < 5.4.0-1051.53 | UNKNOWN |
ubuntu | 18.04 | noarch | linux-azure-5.4 | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-bluefield | < 5.4.0-1013.16 | UNKNOWN |
ubuntu | 20.04 | noarch | linux-gcp | < 5.4.0-1046.49 | UNKNOWN |
ubuntu | 18.04 | noarch | linux-gcp-5.4 | < any | UNKNOWN |
ubuntu | 20.04 | noarch | linux-gkeop | < 5.4.0-1018.19 | UNKNOWN |
ubuntu | 18.04 | noarch | linux-hwe-5.4 | < any | UNKNOWN |
git.kernel.org/linus/08ef1af4de5fe7de9c6d69f1e22e51b66e385d9b (5.13-rc1)
git.kernel.org/stable/c/08ef1af4de5fe7de9c6d69f1e22e51b66e385d9b
git.kernel.org/stable/c/4348d3b5027bc3ff6336368b6c60605d4ef8e1ce
git.kernel.org/stable/c/b246759284d6a2bc5b6f1009caeeb3abce2ec9ff
git.kernel.org/stable/c/c7b0208ee370b89d20486fae71cd9abb759819c1
git.kernel.org/stable/c/f5809ca4c311b71bfaba6d13f4e39eab0557895e
launchpad.net/bugs/cve/CVE-2021-46971
nvd.nist.gov/vuln/detail/CVE-2021-46971
security-tracker.debian.org/tracker/CVE-2021-46971
www.cve.org/CVERecord?id=CVE-2021-46971