Am I affected by Meltdown?! Meltdown (CVE-2017-5754) checker
What am I?
Proof-of-concept /
Exploit /
Checks whether system is affected by Variant 3: rogue data cache load (CVE-2017-5754), a.k.a MELTDOWN.
The basic idea is that user will know whether or not the running system is properly patched with
something like KAISER patchset (https://lkml.org/lkml/2017/10/31/884) for example.
Check out my blog post that guides reader through a Meltdown proof-of-concept: http://funwithbits.net/blog/programmers-guide-to-meltdown/
*** Only works on Linux for now ***
How it works?
It works by using /proc/kallsyms to find system call table and checking whether the address of a
system call found by exploiting MELTDOWN match the respective one in /proc/kallsyms.
Getting started
Clone, then run make to compile the project, then run meltdown-checker:
git clone https://github.com/raphaelsc/Am-I-affected-by-Meltdown.git
cd ./Am-I-affected-by-Meltdown
make
taskset 0x1 ./meltdown-checker
What to do when you face:
-
Unable to read /proc/kallsyms...That's because your system may be preventing the program from reading kernel symbols in
/proc/kallsymsdue to/proc/sys/kernel/kptr_restrictset to1.
The following command will do the tricky:sudo sh -c "echo 0 > /proc/sys/kernel/kptr_restrict" -
Unable to read /boot/System.map-.That could probably be because your system not having
/bootmounted. This program relies on that partition and thus you'd need to mount your/bootpartition first.
Please open an issue if you have an idea on how to fallback to another approach in this scenario.
Example output for a system affected by Meltdown:
Checking whether system is affected by Variant 3: rogue data cache load (CVE-2017-5754), a.k.a MELTDOWN ...
Checking syscall table (sys_call_table) found at address 0xffffffffaea001c0 ...
0xc4c4c4c4c4c4c4c4 -> That's unknown
0xffffffffae251e10 -> That's SyS_write
System affected! Please consider upgrading your kernel to one that is patched with KAISER
Check https://security.googleblog.com/2018/01/todays-cpu-vulnerability-what-you-need.html for more details