Federal agency warns critical Linux vulnerability being actively exploited (arstechnica.com)
from joojmachine@lemmy.ml to linux@lemmy.ml on 31 May 19:06
https://lemmy.ml/post/16314429

#linux

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autotldr@lemmings.world on 31 May 19:10 next collapse

This is the best summary I could come up with:


It’s the result of a use-after-free error, a class of vulnerability that occurs in software written in the C and C++ languages when a process continues to access a memory location after it has been freed or deallocated.

At the time this Ars post went live, there were no known details about the active exploitation.

A deep-dive write-up of the vulnerability reveals that these exploits provide “a very powerful double-free primitive when the correct code paths are hit.” Double-free vulnerabilities are a subclass of use-after-free errors that occur when the free() function for freeing memory is called more than once for the same location.

The write-up lists multiple ways to exploit the vulnerability, along with code for doing so.

The double-free error is the result of a failure to achieve input sanitization in netfilter verdicts when nf_tables and unprivileged user namespaces are enabled.

Some of the most effective exploitation techniques allow for arbitrary code execution in the kernel and can be fashioned to drop a universal root shell.


The original article contains 351 words, the summary contains 168 words. Saved 52%. I’m a bot and I’m open source!

stuckgum@lemmy.ml on 31 May 19:11 next collapse

Yet another security issue that Rust would solve.

GolfNovemberUniform@lemmy.ml on 31 May 19:15 next collapse

There are still slight advantages to C that probably will make some devs stick to it in specific cases

gravitas_deficiency@sh.itjust.works on 31 May 19:22 collapse

But this isn’t one of them

veniasilente@lemm.ee on 31 May 19:57 next collapse

Oh, we heard, Rust is the greatest invention since sliced bread. We heard it already. Like 65534 times.

Zucca@sopuli.xyz on 31 May 20:02 next collapse

Like 65534 times.

So close to full 16-bit max. So close…

veniasilente@lemm.ee on 31 May 20:08 next collapse

Yeah we only need 2 brainRusts more to start seeing some fun.

Zucca@sopuli.xyz on 01 Jun 16:37 collapse

Gah. I should have stated “I see what you did there.” instead. ;)

phoenixz@lemmy.ca on 01 Jun 02:43 collapse

Yeah I figured he was going purposely for a memory overflow

drwho@beehaw.org on 31 May 20:22 next collapse

I wonder how many folks are just refusing to use Rust to spite the Rust Evangelism Strike Team.

swab148@startrek.website on 01 Jun 02:22 next collapse

I wish there was a synonym for “evangelism” that began with a “u”.

eveninghere@beehaw.org on 01 Jun 23:24 next collapse

user

Tlaloc_Temporal@lemmy.ca on 02 Jun 03:04 collapse

Urge? Kinda dark and villainous feeling.

Upgrade! “The Rust Upgrade Strike Team! Upgrade Today!” Sounds very propagandistic, almost doublespeak.

Ultimatum? Mildly threatening.

Utopia? It has the self righteous feel.

Uhvangelism, hurhur.

Universalism?

Templa@beehaw.org on 02 Jun 04:40 collapse

I giggled, thank you.

Templa@beehaw.org on 01 Jun 03:21 next collapse

Rustaceans 🤝 Vegans

delirious_owl@discuss.online on 01 Jun 13:23 collapse

I wait until cargo is actually secure.

uhN0id@programming.dev on 02 Jun 09:19 collapse

What is insecure about it?

delirious_owl@discuss.online on 02 Jun 12:14 collapse

It doesn’t verify downloads are authentic. Its an issue with almost all programming dependency managers besides mature ones like Java’s Maven.

Python has been working with Facebook to fix this in pip for like a decade.

But obviously it shows that rust isn’t so concerned about security.

uhN0id@programming.dev on 02 Jun 17:43 collapse

Ah interesting. Thank you, you’re giving me something to read about that I never considered for crates. I guess I just assumed because of the scrutiny Rust was built with and continues to go through that it would also apply to verifying crates. I have definitely heard about it with NPM so it should have been obvious that it might not be any different for crates. Thanks again!

urska@lemmy.ca on 01 Jun 01:52 next collapse

Aviation, Health, Space and Car industry have only 3 certified languages that they use. Ada, C and C++. Ada is dying because there are way less young engineers who want to invest their future learning it. Then there is C and C++ but they dont offer memory safety and its really hard to master and its really hard and long (thats what she said) to certify the code when being audited for safety by a tier company.

Rust solves by default (no need to review) like 2/3 of the standard requirements those industries have and are that found in C and C++. Rust will soon be approved in this group by the car industry.

Im not a rust fan, but I have 3 things to say about rust.

  • Its fun to program like C++ having the peace of mind knowing the compiler is there helping.
  • You dont feel like youre defusing a bomb like when writing C.
  • Even though its a fun language to write, its also really hard to master, itd say 2 years to be really proficient with it. There is just so much knowledge.
imgcat@lemmy.ml on 01 Jun 05:48 next collapse

Ada SPARK is not dying at all, it’s growing. It is used where formal proof is required like and Rust is nowhere near that!

corsicanguppy@lemmy.ca on 01 Jun 08:55 next collapse

  • You dont feel like youre defusing a bomb like when writing C.

Whoa, Skippy. It’s not saving the world, it’s just coding properly.

urska@lemmy.ca on 02 Jun 13:53 collapse

Well no, those companies deal with really important subjects. Airplanes, car safety, chemotherapy machines, missiles, etc. Have a good day

caseyweederman@lemmy.ca on 01 Jun 13:38 next collapse

Could you explain the “no need to review” part? I do keep hearing good things about Rust.

urska@lemmy.ca on 02 Jun 13:48 collapse

These industries hire third parties to review c and c++ line per line to make sure it’s memory safe. Rust by default forces you to write memory safe code, otherwise it won’t even compile. The rust compiler tells where is the problem and what it expects. No only for basic Type errors but also for concurrent code.

caseyweederman@lemmy.ca on 02 Jun 20:51 collapse

Is it not possible to build that functionality into C/++ compilers?

urska@lemmy.ca on 03 Jun 19:23 collapse

its the way the language was built. Im not sure its possible without breaking C/C++ which have like 35 years + in the making. Also these concepts are have little to do with programing and more architectural designs. The designers are real engineers working on difficult concepts. All big brains tbh

anton@lemmy.blahaj.zone on 01 Jun 15:45 collapse

Aviation, Health, Space and Car industry have only 3 certified languages that they use. Ada, C and C++.

Rust is automotive certified since over half a year. ferrous-systems.com/…/officially-qualified-ferroc…

doona@aussie.zone on 01 Jun 02:02 collapse

I hate it when people talk about new technologies 🤬

veniasilente@lemm.ee on 01 Jun 02:44 collapse

Same. We should head back to ICQ!

leopold@lemmy.kde.social on 01 Jun 06:42 collapse

eh, still beats Discord as far as I’m concerned

VerseAndVermin@lemmy.world on 01 Jun 08:26 collapse

Yeah, but no one will hop on irc or mumble to hang out these days.

uhN0id@programming.dev on 02 Jun 09:13 next collapse

God I miss the IRC days

veniasilente@lemm.ee on 02 Jun 18:24 collapse

Not with that attitude!

I’m already on IRC and XMPP. be the change you want to see.

henfredemars@infosec.pub on 31 May 21:30 next collapse

I don’t think it’s realistic to expect a rewrite of code that works. Maybe over time we can start implementing pieces in safer languages.

Barx@hexbear.net on 31 May 22:48 next collapse

It’s realistic if security is a priority.

eveninghere@beehaw.org on 01 Jun 23:28 collapse

I admit C++ ain’t safe, but wonder if there’s an alternative to going Rust. Don’t get me wrong, I love the language. But Rust is a beast on its own. I read here that game devs generally can’t adapt Rust because the language forces frequent refactoring, which doesn’t fit the business speed of game development.

henfredemars@infosec.pub on 01 Jun 23:35 collapse

I don’t care for Rust because I like writing unsafe code. It’s fun. However, I would value the assurances it provides using software written in Rust.

DacoTaco@lemmy.world on 31 May 23:01 next collapse

Serious question, how would using rust avoid this? Rust still has reference types in the background, right? Still has a way to put stuff on the heap too? Those are the only 2 requirements for reusing memory bugs

sleep_deprived@lemmy.world on 01 Jun 00:10 collapse

This is a use-after-free, which should be impossible in safe Rust due to the borrow checker. The only way for this to happen would be incorrect unsafe code (still possible, but dramatically reduced code surface to worry about) or a compiler bug. To allocate heap space in safe Rust, you have to use types provided by the language like Box, Rc, Vec, etc. To free that space (in Rust terminology, dropping it by using drop() or letting it go out of scope) you must be the owner of it and there may be current borrows (i.e. no references may exist). Once the variable is droped, the variable is dead so accessing it is a compiler error, and the compiler/std handles freeing the memory.

There’s some extra semantics to some of that but that’s pretty much it. These kind of memory bugs are basically Rust’s raison d’etre - it’s been carefully designed to make most memory bugs impossible without using unsafe. If you’d like more information I’d be happy to provide!

paysrenttobirds@sh.itjust.works on 01 Jun 05:24 next collapse

The way I understand it, it is a bug in C implementation of free() that causes it to do something weird when you call it twice on the same memory. Maybe In Rust you can never call free twice, so you would never come across this bug. But, also Rust probably doesn’t have the same bug.

My point is it seems it is a bug in the underlying implementation of free(), not to be caught by the compiler, and can’t Rust have such errors no matter its superior design?

Feyd@programming.dev on 01 Jun 06:07 next collapse

The way that rust attempts to prevent this class of error is not by making an implementation of free that is safe to call twice, but by making the compiler refuse to compile programs where free could be called twice on a pointer.

Anyway, use after free doesn’t depend on a double free. It just means that the program frees memory but keeps the pointer (which now points at memory that could contain unrelated data at some future point in time) and if someone trying to exploit the program finds a way to induce the program to read or write to that memory they may be able to access data they are not expected to, or write data to be used by a different part of the program that they shouldn’t be able to

paysrenttobirds@sh.itjust.works on 01 Jun 21:00 collapse

Thanks, I understand the problem with using memory after it’s been freed and possibly access it changed by another part of the process. I guess I was confused by the double free explanation I read, which didn’t really say how it could be exploited, but I think you are right it still needs to be accessed later by the original program, which would not happen in Rust.

Nibodhika@lemmy.world on 01 Jun 13:11 collapse

Not really, the issue is that C/C++ is not memory safe, i.e. it allows you to access memory that has already been freed. Consider the following C++ code:

int* wrong() {
  int data  = 10;
  return &data;
}

If you try to use it it looks correct:

int* ptr = wrong();
std::cout << *ptr << std::endl;

That will print 10, but the memory where data was defined has been freed, and is no longer in control of the program. Meaning that if something else allocated that memory they can control what my program does.

Consider that on that example above later in the program we do:

user.access_level = *ptr;

If someone manages to get control of that memory between when we freed it and we used it they can make the access_level of the user be whatever they want.

This is a problem with C/C++ allowing you to access memory that has been freed, which is why C/C++ programmers need to be extra careful.

paysrenttobirds@sh.itjust.works on 01 Jun 20:57 collapse

Thank you, that is very clear.

DacoTaco@lemmy.world on 01 Jun 11:49 collapse

Thanks for the response. Ive heard of rust’s compiler being very smart and checking a ton of stuff. Its good thing it does, but i feel like there are things that can cause this issues rust cant catch. Cant put my finger on it.
What would rust do if you have a class A create something on the heap, and it passes this variable ( by ref ? ) to class B, which saves the value into a private variable in class B. Class A gets out of scope, and would be cleaned up. What it put on the heap would be cleaned up, but class B still has a reference(?) to the value on the heap, no? How would rust handle such a case?

been_jamming@lemm.ee on 01 Jun 13:35 next collapse

It’s not like C where you have control over when you can make references to data. The compiler will stop you from making references in the cases where a memory bug would be possible.

mhague@lemmy.world on 01 Jun 15:07 next collapse

You use lifetimes to annotate parameters and return values in order to tell the compiler about how long things must last for your function to be valid. You can link a specific input with the output, or explicitly separate them. If you don’t give lifetimes the language uses some basic rules to do it for you. If it can’t, eg it’s ambiguous, then it’s a compile error and you need to do it manually.

It’s one of the harder concepts of rust to explain succinctly. But imagine you had a function that took strA and strB, used strB to find a subsection of strA, and then return a slice of strA. That slice is tied to strA. You would use 'a annotation for strA and the return value, and 'b for strB.

Rust compiler will detect the lifetime being shorter than expected.


Also, ownership semantics. Think c++ move semantics. Only one person is left with a good value, the previous owners just have garbage data they can’t use anymore. If you created a thing on the heap and then gave it away, you wouldn’t have it anymore to free at the end. If you want to have “multiple owners” then you need ref counting and such, which also stops this problem of premature freeing.


Edit: one more thing: reference rules. You can have many read-only references to a thing, or one mutable reference. Unless you’re doing crazy things, the compiler simply won’t let you have references to a thing, and then via one of those references free that thing, thereby invalidating the other references.

DacoTaco@lemmy.world on 03 Jun 11:08 collapse

Thats interresting, thanks! Stuff for me to look into!
I also think halfway through the conversation i might have given the impression i was talking about pointers, while it was not my intention to do so. That said, the readonly/mutable reference thing is very interresting!
Ill look into what rust does/has that is like the following psuedocode :

DataBaseUser variable1 = GetDataBaseUser(20);
userService.Users.Add(variable1);
variable1 = null; // or free?
[end of function scope here, reference to heap now in list ]

mhague@lemmy.world on 03 Jun 14:50 collapse

No problem. I’m no guru and I’m currently on Zig but I think learning some Rust is a really fast way to hone skills that are implied by other languages.

ProgrammingSocks@pawb.social on 02 Jun 03:56 collapse

Rust simply doesn’t allow you to have references to data that goes out of scope (unless previously mentioned hoops are jumped through such as an explicitly declared unsafe block). It’s checked at compile time. You will never be able to compile the program.

Rust isn’t C. Rust isn’t C++. The memory-safe-ness of it is also not magic, it’s a series of checks in the compiler.

DacoTaco@lemmy.world on 03 Jun 11:03 collapse

That sounds odd. That also means that a mapper, command, service,… can never return a class object or entity. Most of the programming world is based on oop o.O
Keep in mind im not talking about the usage of pointers, but reference typed variables.

ProgrammingSocks@pawb.social on 03 Jun 18:44 collapse

Oh sure, I’m still learning so I thought you meant references as in pointers like in C++. But also, Rust isn’t a strictly object oriented language either. It shares a lot of similar features, but they aren’t all the typical way you’d do things in an OOP language. You should check out the chapter of the Rust book for ownership.

corsicanguppy@lemmy.ca on 01 Jun 08:52 next collapse

Yet another problem that actually updating your shit - which is trivially easy on enterprise Linux - would fix.

It’s part of the 95% of problems solved by actually updating your enterprise Linux host.

delirious_owl@discuss.online on 01 Jun 13:22 next collapse

unattended-upgrades and forget about it

KISSmyOSFeddit@lemmy.world on 01 Jun 13:25 next collapse

oops, our third party application broke again

delirious_owl@discuss.online on 01 Jun 13:41 collapse

Never happened to me when set to security.

iegod@lemm.ee on 01 Jun 15:01 collapse

Tell me more (for real, I’m unfamiliar).

delirious_owl@discuss.online on 01 Jun 15:36 collapse

Its a Debian package that automatically upgraded packages (if they have pending security updates)

iegod@lemm.ee on 01 Jun 16:28 collapse

I run mine manually, good to know. Will check it out.

ikidd@lemmy.world on 02 Jun 13:58 next collapse

But then I can’t screenshot my 7 years of uptime

possiblylinux127@lemmy.zip on 02 Jun 15:00 collapse

Just live patch

Although it is better to have some sort of HA system.

possiblylinux127@lemmy.zip on 02 Jun 15:00 collapse

That requires that the patches be in the repos. With RHEL it might be a few months

fruitycoder@sh.itjust.works on 02 Jun 15:48 collapse

Normally security patches are pretty good on same day releases as the CVE if available.

the_doktor@lemmy.zip on 01 Jun 14:42 next collapse

Any software can have security issues, including ones written in rust. Just because C/C++ allows one to shoot oneself in the foot doesn’t mean it’s something that’s commonly allowed by anyone with any skill, it’s just a bug like anything else. I swear, people advocating rust believe that it’s something intrinsic in C/C++ that allows such a thing regardless of what a developer does, and it’s getting tiresome.

Miaou@jlai.lu on 01 Jun 22:53 next collapse

But it is, do you not understand what rust brings compared to these two languages ?

the_doktor@lemmy.zip on 02 Jun 06:42 collapse

A language for noobs that encourages bad style and programming because you can’t shoot yourself in the foot as easily (but you totally still can)? That’s what all these fad languages seem to be, and more keep popping up and declaring themselves the future of programming all the time. Just wait, rust will be forgotten for some other fad language everyone will start using soon enough. Stop reworking everything into the fad language of the moment and just work on existing code.

uhN0id@programming.dev on 02 Jun 09:10 next collapse

I’m sorry but this reads like someone that hasn’t used Rust or hasn’t spent much time with it. You’re generalizing Rust with other languages while forgetting that some fads turn into standards.

If everyone stopped trying new things we’d never see progress.

Edit: fixed typo

Kazumara@discuss.tchncs.de on 02 Jun 16:15 collapse

A language for noobs

That assertion surprises me; I find C easier to use than Rust.

ProgrammingSocks@pawb.social on 02 Jun 03:52 collapse

Of course a good developer can avoid these problems for the most part. The point is that we want the bad developers to be forced to do things a safe way by default.

pathief@lemmy.world on 02 Jun 12:14 collapse

Even good developers make mistakes. It’s really nice to catch these mistakes at compile time.

possiblylinux127@lemmy.zip on 02 Jun 14:58 collapse

The problem is bad programmers. You can write good C code but it takes more effort and security checking. You also can write vulnerable and sloppy Rust code.

treadful@lemmy.zip on 31 May 20:12 next collapse

It’s a privilege escalation.

The vulnerability, tracked as CVE-2024-1086 and carrying a severity rating of 7.8 out of a possible 10, allows people who have already gained a foothold inside an affected system to escalate their system privileges. It’s the result of a use-after-free error, a class of vulnerability that occurs in software written in the C and C++ languages when a process continues to access a memory location after it has been freed or deallocated. Use-after-free vulnerabilities can result in remote code or privilege escalation.

corsicanguppy@lemmy.ca on 01 Jun 08:50 next collapse

a use-after-free error, a class of vulnerability that occurs in software written in the C and C++ languages when a process continues to access a memory location after it has been freed or deallocated.

Immediately I noticed how when Teslas can’t drive themselves we also blame the car and not the driver.

Weak. Blame the driver.

caseyweederman@lemmy.ca on 01 Jun 13:35 next collapse

I compiled my own drivers

eveninghere@beehaw.org on 01 Jun 23:21 next collapse

This guy drives not

No1@aussie.zone on 01 Jun 23:22 next collapse

Yeah, but did you include any biobs?

Tlaloc_Temporal@lemmy.ca on 02 Jun 02:35 collapse

And then compacted them!

lord_ryvan@ttrpg.network on 01 Jun 16:13 next collapse

Don’t think C / C++ wasn’t blamed.

Mango@lemmy.world on 01 Jun 16:16 next collapse

And the horse it ride in on!

LeFantome@programming.dev on 01 Jun 17:12 collapse

I re-wrote my Tesla firmware in Rust. It is faster and more secure. Self-driving is no problem when you use a safe language.

Honestly, why are we even selling cars to people who do not take these basic steps?

JonnyRobbie@lemmy.world on 01 Jun 09:34 next collapse

rust mentioned, lets goo

fossphi@lemm.ee on 01 Jun 10:03 collapse

Blazingly fast 🚀

konju376@lemmy.blahaj.zone on 02 Jun 09:25 collapse

Zero-cost abstractions!

possiblylinux127@lemmy.zip on 02 Jun 14:57 collapse

This is why least privilege is so important. If one account is compromised it will be harder to compromise others if the original account is isolated.

applepie@kbin.social on 31 May 20:24 next collapse

Is this even new?

I thought this already circulated a few months back.

lemmyvore@feddit.nl on 31 May 23:07 collapse

Even Debian stable has already patched it.

possiblylinux127@lemmy.zip on 31 May 23:27 next collapse

Debian is actually one of the fastest patchers

RHEL on the other hand

caseyweederman@lemmy.ca on 01 Jun 13:40 collapse

Security patches do the opposite of break stuff

TeddyKila@hexbear.net on 31 May 20:24 next collapse

Rolling release stays winning

rcbrk@lemmy.ml on 01 Jun 14:17 next collapse

btw

possiblylinux127@lemmy.zip on 02 Jun 14:55 collapse

Until it doesn’t. The problem will rolling releases is that a lot of security issues are introduced quickly. Debian has far fewer security problems than Arch.

drwho@beehaw.org on 31 May 20:24 next collapse

Outfits that haven’t installed patches since February are getting popped in May by a vuln that was published in January.

QuazarOmega@lemy.lol on 01 Jun 07:18 next collapse

Outfits? What does it mean in this context?

Waltzy@feddit.uk on 01 Jun 08:32 next collapse

Organisations

QuazarOmega@lemy.lol on 01 Jun 08:39 collapse

Ahh, thank you

acockworkorange@mander.xyz on 02 Jun 04:15 next collapse

Suits and shit.

possiblylinux127@lemmy.zip on 02 Jun 14:54 next collapse

Guns for hire

drwho@beehaw.org on 03 Jun 16:28 collapse

Companies and organizations.

jjlinux@lemmy.ml on 01 Jun 13:45 collapse

Normal technology situations created by normal human behavior. 😜

bigkahuna1986@lemmy.ml on 31 May 21:52 collapse

Is there a way to jailbreak an Android phone using this exploit?

possiblylinux127@lemmy.zip on 31 May 23:27 collapse

You could just unlock the bootloader

JCreazy@midwest.social on 31 May 23:29 collapse

Assuming the bootloader is unlockable

delirious_owl@discuss.online on 01 Jun 13:21 collapse

You could just buy an android phone that encourages this. All Pixels, for example.

asexualchangeling@lemmy.ml on 01 Jun 16:58 next collapse

“Buy a different phone” is not an option for everybody

delirious_owl@discuss.online on 01 Jun 22:32 collapse

No, but buy a different one when this one breaks is.

asexualchangeling@lemmy.ml on 01 Jun 22:44 collapse

Which doesn’t solve the problem for either me or the person who asked the question, yes I know better than to get a Samsung now, but I plan on keeping my phone for as long as I can regardless

Saying something we already know doesn’t help anybody

delirious_owl@discuss.online on 01 Jun 23:03 next collapse

Of course it helps them

ji17br@lemmy.ml on 02 Jun 05:13 collapse

Username checks out.

possiblylinux127@lemmy.zip on 02 Jun 14:54 collapse

It helps them long term

ProgrammingSocks@pawb.social on 03 Jun 19:34 collapse

+1 for Pixels but -1 for Google’s “support”. You’ll never talk to a human with them. I love GrapheneOS on my Pixel though, and they’re really the only phones you can install it on cause you can re-lock the bootloader on it after installing. CalyxOS (fork of Graphene with slightly less sandboxing) does support FairPhone 4&5 and a few Motorola phones though.