Spectre & Meltdown Checker for Linux

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GET: GitHub - speed47/spectre-meltdown-checker: Spectre & Meltdown vulnerability/mitigation checker for Linux

A simple shell script to tell if your Linux installation is vulnerable against the 3 "speculative execution" CVEs that were made public early 2018.
Without options, it'll inspect your currently running kernel. You can also specify a kernel image on the command line, if you'd like to inspect a kernel you're not running.
The script will do its best to detect mitigations, including backported non-vanilla patches, regardless of the advertised kernel version number.​

Summary of CVEs

CVE-2017-5753 bounds check bypass (Spectre Variant 1)

• Impact: Kernel & all software
• Mitigation: recompile software and kernel with a modified compiler that introduces the LFENCE opcode at the proper positions in the resulting code
• Performance impact of the mitigation: negligible

CVE-2017-5715 branch target injection (Spectre Variant 2)

• Impact: Kernel
• Mitigation 1: new opcode via microcode update that should be used by up to date compilers to protect the BTB (by flushing indirect branch predictors)
• Mitigation 2: introducing "retpoline" into compilers, and recompile software/OS with it
• Performance impact of the mitigation: high for mitigation 1, medium for mitigation 2, depending on your CPU

CVE-2017-5754 rogue data cache load (Meltdown)

• Impact: Kernel
• Mitigation: updated kernel (with PTI/KPTI patches), updating the kernel is enough
• Performance impact of the mitigation: low to medium