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Re: Question on CVE-2017-5754 on Debian 8.9





On 24 January 2018 at 11:52, Michael Fothergill <michael.fothergill@gmail.com> wrote:


On 24 January 2018 at 11:21, Michael Fothergill <michael.fothergill@gmail.com> wrote:


On 24 January 2018 at 10:53, Michael Fothergill <michael.fothergill@gmail.com> wrote:




The neowin link above has a link to a Phoronix article[1], which
suggests you need GCC 8.0, or maybe 7.3 if a backport succeeds. That was
9 days ago, of course ... Stretch only has 6.3, and even sid only has
7.2, so I don't see it hitting debian soon.

Richard

[1]
https://www.phoronix.com/scan.php?page=news_item&px=Linux-4.9-4.14-Retpoline

​Some new patches are coming soon:



I have posted a query on the gentoo forum asking if I have a recent enough version of gcc etc for the retpoline.

There is a test program you can install and run and it will tell you if both the meltdown and spectre patched are installed which I will try out.

Looks like your all going to have to run the latest kernels....(J)

Regards

MF


​PS I installed the spectre meltdown checker and ran it:djt /home/mikef/spectre-meltdown-checker # ./spectre-meltdown-checker.sh
Spectre and Meltdown mitigation detection tool v0.32

Checking for vulnerabilities on current system
Kernel is Linux 4.14.14-gentoo #1 SMP Tue Jan 23 13:06:23 GMT 2018 x86_64
CPU is AMD A10-7850K Radeon R7, 12 Compute Cores 4C+8G

CVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'
* Mitigated according to the /sys interface:  NO  (kernel confirms your system is vulnerable)
> STATUS:  VULNERABLE  (Vulnerable)

CVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'
* Mitigated according to the /sys interface:  NO  (kernel confirms your system is vulnerable)
* Mitigation 1
  * Hardware support (CPU microcode)
    * Indirect Branch Restricted Speculation (IBRS)
      * SPEC_CTRL MSR is available:  NO
      * CPU indicates IBRS capability:  NO
    * Indirect Branch Prediction Barrier (IBPB)
      * PRED_CMD MSR is available:  NO
      * CPU indicates IBPB capability:  NO
  * Kernel is compiled with IBRS/IBPB support:  NO
  * Currently enabled features
    * IBRS enabled for Kernel space:  NO
    * IBRS enabled for User space:  NO
    * IBPB enabled:  NO
* Mitigation 2
  * Kernel compiled with retpoline option:  YES
  * Kernel compiled with a retpoline-aware compiler:  NO  (kernel reports minimal retpoline compilation)
  * Retpoline enabled:  YES
> STATUS:  VULNERABLE  (Vulnerable: Minimal AMD ASM retpoline)

CVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'
* Mitigated according to the /sys interface:  YES  (kernel confirms that your CPU is unaffected)
* Kernel supports Page Table Isolation (PTI):  YES
* PTI enabled and active:  NO
* Running under Xen PV (64 bits):  NO
> STATUS:  NOT VULNERABLE  (your CPU vendor reported your CPU model as not vulnerable)

A false sense of security is worse than no security at all, see --disclaimer
djt /home/mikef/spectre-meltdown-checker #

ie it's there but GCC 7.2 can't install it.

If you look at the discussion here:


you will see that I need to install gcc 7.3.0rc1

time to compile your own kernels...

Cheers

MF

​PPS

GCC 7.3 is coming soon:


so, problem solved....

​The link within the above one: ​
https://gcc.gnu.org/ml/gcc/2018-01/msg00148.html
​also has a link to the ftp download for the release candidate version of gcc 7.3 ie 7.3.0rc1 which does actually work for spectre and retpoline.

So while waiting for the official release of 7.3. we could do a manual installation of gcc 7.3.0 rc1 from the tar file and somehow uninstall the current gcc deb file in stretch
and plumb in the manually compiled 7.3 rc1 edition into the debian install.

Then we can install the 4.14.14 kernel.

A doddle.







 







 






 





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