CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability

For customers who cannot update immediately and doesn't have Secure Boot feature enabled, the issue can be mitigated by executing the following steps: 1) Install required systemtap packages and dependencies as per - pointed by https://access.redhat.com/solutions/5441 2) Install polkit debug info: ~~~ debuginfo-install polkit ~~~ 3) Create the following systemtap script, and name it pkexec-block.stp: ~~~ probe process("/usr/bin/pkexec").function("main") { if (cmdline_arg(1) == "") raise(9); } ~~~ 4) Load the systemtap module into the running kernel: ~~~ stap -g -F -m stap_pkexec_block pkexec_block.stp ~~~ 5) Ensure the module is loaded: ~~~ lsmod | grep -i stap_pkexec_block stap_pkexec_block 434176 0 ~~~ 6) Once polkit package was updated to the version containing the fix, the systemtap generated kernel module can be removed by running: ~~~ rmmod stap_pkexec_block ~~~ This mitigation doesn't work for Secure Boot enabled system as SystemTap would require an external compiling server to be able to sign the generated kernel module with a key enrolled into the Kernel's keyring.