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Add mitigations(7) describing our vulnerability mitigations
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Authored by emaste on Sep 9 2023, 1:01 AM.
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emaste requested review of this revision.Sep 9 2023, 1:01 AM
emaste updated this revision to Diff 127163.
emaste created this revision.

fill in placeholder

Lots to add still, including hw mitigations

machdep.mitigations.rngds.state: Not applicable
machdep.mitigations.rngds.enable: 1
machdep.mitigations.flush_rsb_ctxsw: 1
machdep.mitigations.taa.state: TSX not present
machdep.mitigations.taa.enable: 0
machdep.mitigations.mds.disable: 0
machdep.mitigations.mds.state: inactive
machdep.mitigations.ssb.disable: 0
machdep.mitigations.ssb.active: 0
machdep.mitigations.ibrs.disable: 1
machdep.mitigations.ibrs.active: 0

PROT_MAX

compile-time options (PIE, RELRO, BIND_NOW)

SMEP/SMAP/PAN/PXN

Flesh out list and add some .Xrs

connect to build, add .Xr from security, expand on more mitigations

Here is a diff below containing a whole new part on hardware mitigations, with a general introduction and a specific section for Zenbleed.

Please tell me if you find it too detailed or not at the right level of language.

I'm attaching the diff here since I can't update this differential revision. I could create another one if you prefer. I'm unsure which collaborative workflow is best for large edits from multiple people.

Thanks.

{F67700098}

Phab is just showing {F67700098} not the diff you attached.

In any case you're right, phab is not great for collaborative editing. I can either incorporate your text if you want to just mail it or paste it in a comment and add a Co-authored-by: tag, or we can commit an interim version of this page (without connecting it to the build at first) and iterate on it in the tree.

Phab is just showing {F67700098} not the diff you attached.

Ah, sorry about that. I had had the same issue yesterday when viewing the page while not being logged, but after logging I could see the name of the file and a download button, so I assumed it would be OK when you're logged. But since you commented (logged), something else is probably going on.

In any case you're right, phab is not great for collaborative editing. I can either incorporate your text if you want to just mail it or paste it in a comment and add a Co-authored-by: tag, or we can commit an interim version of this page (without connecting it to the build at first) and iterate on it in the tree.

Sending it to you by mail for now (only the plain mitigations.7, which is a drop-in replacement). Iterating in the tree would be OK as well (once I can actually do that).

emaste added reviewers: olce, secteam.

Add Zenbleed info from @olce.freebsd_certner.fr

lots of mentions of "FreeBSD" in the text. Should we replace that with .Fx?

minor edits found in self-review

LGTM from manpages , it would be great to have this included for 14.0-RELEASE.

This revision is now accepted and ready to land.Oct 4 2023, 8:28 AM
share/man/man7/mitigations.7
98

New sentence new line

106

It sounds too positive to me.

120

Perhaps explain what is different between PIE and 'older' binaries WRT ASLR.

146

Note that ASLR mode change for process become effective on address space change, ie. on execve(2).

163

NSNL

165

May be explain that typical victim are JIT-like programs, and that under w^x mode they need to be modified to write executable data, then change the page mode with mprotect(2).

195

Missed explanation?

209
213

Needs to explain that ABI is broken.

217

What does this title do there?

245

Sometimes sw mitigations depends on hw capabilities presented by microcode updates.

312

NSNL

343

.Xr cpucontrol 8
both for direct MSR manipulations and ucode update

emaste added inline comments.
share/man/man7/mitigations.7
106

I can just delete the 2nd sentence.

share/man/man7/mitigations.7
106

You might state s/defense/claims to improve protection/ or similar.

emaste marked 7 inline comments as done.

some feedback from kib

This revision now requires review to proceed.Oct 4 2023, 11:58 PM

Found a few typos.

share/man/man7/mitigations.7
176

s/excutable/executable/

178

s/excutable/executable/

234

s/have seeing/have seen/
Or simplify this as it's not the years that have "seen" things. Maybe start the sentence with "A growing number of new hardware vulnerabilities..."

This revision was not accepted when it landed; it landed in state Needs Review.Oct 5 2023, 5:53 PM
This revision was automatically updated to reflect the committed changes.