[plg94]

the bad actor was a co-maintainer of the repo (and even more active than the original maintainer for quite some time) with full commit rights. This was strait committed to master, no PR and no review required.

edit: also this was heavily obfuscated in some binary files that were marked as test files ("good" and "bad" xz compressed test file). No way to spot this if you don't know what you're looking for.

[jghn]

Not only were they a co-maintainer, but if you're relying on code review to ensure correctness and security, you've already lost the battle.

Code reviews are more about education and de-siloing.

[barfbagginus]

Assume your co-contibutor was not always malicious. They passed all past vetting efforts. But their motives have changed due to a secret cause - they're being extorted by a criminal holding seriously damaging material over them and their family.

What other controls would you use to prevent them contributing malicious commits, besides closely reading your co-contributor's commits, and disallowing noisy commits that you don't fully comprehend and vouch for?

We assume that it'd be unethical to surveil the contributor well enough to detect the change in alliance. That would violate their privacy.

Is it reasonable to say, "game over, I lose" in that context? To that end, we might argue that an embedded mole will always think of ways to fool our review, so this kind of compromise is fatal.

But let's assume it's not game over. You have an advanced persistent threat, and you've got a chance to defeat them. What, besides reviewing the code, do you do?

[edflsafoiewq]

In open source, code review is absolutely about correctness and security.

[ajross]

Yeah, no. Code review isn't going to catch all bugs, but it does catch a ton as long as it's done sincerely and well. You'd have an extremely hard time trying to sneak code with a syntax problem like this into Linux, for example. The community values and rewards nitpickery and fine-toothing, and for good reason.

[SV_BubbleTime]

In addition… if your build system has things like this as OK:

> xz -dc $top_srcdir/tests/files/$p | eval $i | LC_ALL=C sed "s/\(.\)/\1\n/g" | LC_ALL=C awk 'BEGIN{FS="\n";RS="\n";ORS="";m=256;for(i=0;i<m;i++){t[sprintf("x%c",i)]=i;c[i]=((i*7)+5)%m;}i=0;j=0;for(l=0;l<8192;l++){i=(i+1)%m;a=c[i];j=(j+a)%m;c[i]=c[j];c[j]=a;}}{v=t["x" (NF<1?RS:$1)];i=(i+1)%m;a=c[i];j=

You should probably expect the potential for abuse?

We’re moving towards complexity that is outpacing human ability for any one person to understand, explain, and thus check an entire object.

And for what? Build efficiency? Making a “trick” thing? When was the project ever going to go back and make things simpler? (Never)

[necubi]

I’m not sure why you’d say that we’re “moving towards” this sort of build system complexity.

This is 1990s autoconf bs that has not yet been excised from the Linux ecosystem. Every modern build system, even the really obtuse ones, are less insane than autoconf.

And the original purpose of this was not for efficiency, but to support a huge variety of target OSes/distros/architectures, most of which are no longer used in any real capacity.

[mrb]

To be clear: the build system did not use the code fragment you quoted. This complex awk code is a later stage of the backdoor.

[Martinussen]

> No way to spot this if you don't know what you're looking for.

I would expect most people to at least ask for more clarification on random changes to `head` offsets, honestly - or any other diff there.

If they had access to just merge whatever with no oversight, I guess the blame is more on people using this in other projects without vetting their basic security of projects they fully, implicitly trust, though. As bad as pulling in "left-pad" in your password hashing lib at that point.

The "random binaries in the repo" part is also egregious, but more understandable. Still not something that should have gotten past another pair of eyes, IMHO.

[chii]

> without vetting their basic security of projects they fully

this sort of vetting you're talking about is gonna turn up nothing. Most vetting is at the source code level anyway, not in the tests, nor the build files tbh. It's almost like a checkbox "cover your ass" type work that a hired consultant would do.

Unless you're someone in gov't/military, in which case yes, you'd vet the code deeply. But that costs an arm and a leg. Would a datacenter/hosting company running ssh servers do that?

[1letterunixname]

This is the problem of projects that allow direct access and lack code review.