A backdoor in xz [LWN.net]

A backdoor in xz

Posted Mar 30, 2024 18:36 UTC (Sat) by Cyberax (✭ supporter ✭, #52523)
In reply to: A backdoor in xz by bluca
Parent article: A backdoor in xz

Sorry, but random dlopen()s are even MORE unacceptable. It also prevents very useful security measures like locking the text of the running executable.

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A backdoor in xz

Posted Mar 30, 2024 19:14 UTC (Sat) by andresfreund (subscriber, #69562) [Link] (2 responses)

It doesn't prevent that at all? Unless you use text relocations, .text should only be mapped read only. And .got would have been remapped ro at start if you use -z now -z relro. Dlopen() doesn't change any of that?

A backdoor in xz

Posted Mar 30, 2024 19:41 UTC (Sat) by Cyberax (✭ supporter ✭, #52523) [Link] (1 responses)

I mean, locking down the complete set of executable pages in a process, so that no new code can't get loaded. OpenBSD has mseal() that can do that.

> Dlopen() doesn't change any of that?

Indeed it doesn't (right now), but expanding its usage will make it harder to enable something like mseal() later.

A backdoor in xz

Posted Mar 31, 2024 13:13 UTC (Sun) by bluca (subscriber, #118303) [Link]

You can still do that, but then you lose some features. That seems like a perfectly acceptable trade-off to me.