Pixel 11 doesn't meet the GrapheneOS security standards and may be skipped

DontStop

Cellobright in the end if I read it correctly MTE needs a dedicated RAM storage for the tags

I think MTE uses TBI? Which means it uses 'normal' memory.

Kernel docs seem to agree:
https://docs.kernel.org/arch/arm64/memory-tagging-extension.html

Please correct me if i am wrong!

Cellobright Really hope Google would change and maybe see the competition and improve security, because when Motorola makes secure phones, Google may lose enterprise and governmental contracts for their phones.

While late, i just wanted to agree with @Tylorw1 (If i understand him correctly (I don't know neutral forms so sorry)) that enterprise and govs are more into iPhones so Google has really nothing to lose here (And i think Motorola not much to gain)

Also sorry if it's hard to read (English is not my native language)

I wanted to write it earlier but needed to do something :)

Tylorw1

DontStop Not knowing much about MTE, but simply asking Gemini some questions (so don't take this as gospel), it's hard to determine why it's removed or not used. Though, it does appear that MTE, while enhancing security, also has its own vulnerabilities. Maybe Google knows something about a lot more vulnerabilities than are published, and decided the performance impact isn't worth the security benefits.

I hope Google eventually provides some clarification.

Novaliss

Tylorw1
https://discuss.grapheneos.org/d/11951-ai-generated-text-is-forbidden-with-the-exception-of-automated-translation

Tylorw1

Novaliss ok? I didn't copy and paste any AI generated text so no clue what you are referring to.

Novaliss

Tylorw1 but you repeated what Gemini just answered you about MTE, didn't you?

Tylorw1

Novaliss And Gemini doesn't provide the sources, which I did go to a couple. For example, USENIX and arxiv that I went to?

People forget AI is also a way to find sources and interpret them. I gave my opinion and speculation on Google's move, not Geminis.

Foggy

DontStop MTE doesn't need an extra memory chip for storing tags - using a part of the existing memory is fine. So you only pay a 3.125% memory cost for the pages you want to store tags. Effectively you can partition physical address space into one part for data and one part for tags, storing both in the same DRAM chip.

TBI refers to the portions of pointers that are used. ie, roughly speaking each 128 bit memory word gets one of 16 colors (the 4 bit tag). Then each pointer gets one of 16 colors on 4 upper bits by using TBI. If you try to use a pointer of one color to access a memory location with a different color then you get an exception.

DontStop

Tylorw1 From what i know MTE 'vulnerabilities' are:
Tag collisions (Not really a vulnerability), which are unavoidable but are just false positive when memory test passes but shouldn't, which doesn't harm security compared to lack of MTE.
Potential kernel MTE code vulnerability, but it's neglible because you mitigate a lot more and I haven't heard of anything like 'Linux MTE implementation vulnerability'.

Regarding performance, it's I think around 3% for async/asymm and around 20% for sync, and asymm already provides huge security benefit, but I am not sure if you can use async/asymm for kernel.

From a quick search (haven't read it fully):
'On the other hand, asynchronous mode is less costly, with a performance overhead estimate of 1-2% across workloads and benchmarks tested.'
https://developer.arm.com/community/arm-community-blogs/b/architectures-and-processors-blog/posts/enhanced-security-through-mte

I suspect @de0u knows a lot more than I and could say something more (also is it okay to tag you de0u?).

I wanted to use '~' for numbers but it made them small so i replaced it with 'around'. Anyone knows solution?

FaberCastell

Novaliss
Clearly not 'ai generated text'

Tylorw1

DontStop More information is always good. That is why from Googling and finding research about it it's hard for me to make a determination as I don't see a reason why.

But, what my mind goes to is what if Google starts to deprecate MTE on Android? We are just totally clueless as to Google's reasoning to not include it in their OWN phones when it seems something they helped create.

All speculation at this point. Cmon Google!

Well see, but is also something GOS has to take into consideration.

Novaliss

FaberCastell Maybe I'm a bit jumpy.. I just read no source besides Gemini for the claim about "MTE vulnerabilities"

DontStop

Foggy Sorry! I haven't found a lot of time for research lately due to work, even though MTE was on my 'to-research list' for a long time!

FaberCastell

Novaliss
Fair :)
I'd suggest there's a difference between copypasting a response as one's own opinion and seeking knowledge and interpreting it
But, yeah, everyone's wary of and sick of the former

DontStop

Tylorw1 I don't think it's likely for MTE on Android to be deprecated, it's becoming basically standard on arm.

Tylorw1

Novaliss Vulnerabilities do exist (regardless of severity) whether from Google Search, Gemini, Gemini Sources, or other posters on here. To say they don't would be a lie. I didn't state in the post I saw anything (vulnerability or performance impact) that posed enough reason to not use MTE (because it still appears better to use than not and as with anything there is an offsetting cost which didn't seem high enough for Google not to use it), which led to me saying Google knows something we don't. Is GOS more secure with MTE. Yes. Is it foolproof? No.

de0u

DontStop I wanted to use '~' for numbers but it made them small so i replaced it with 'around'. Anyone knows solution?

Put a backslash before the tilde.

Tylorw1

DontStop I don't think so either, but something to look into.

My career is in business process, risk, etc. So I think of these things and I would want it confirmed. Lol.

bimbam

let's see. I hope that we will get support for the Pixel 11 anyway :)
I had already bought one, since there is a nice trade in offer

DontStop

Tylorw1 I (to some extend) agree with @Novaliss, and having at least one other source would be a lot better.

Also i don't know if mods will like changing topics from MTE to LLM's :)

DontStop

Tylorw1 What do you mean by foolproof?

de0u Dumb of me to not think about escape character!

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