oss-sec mailing list archives
Re: lockdown bypass on mainline kernel for loading unsigned modules
From: Jann Horn <jannh () google com>
Date: Mon, 15 Jun 2020 19:02:51 +0200
On Mon, Jun 15, 2020 at 6:24 PM John Haxby <john.haxby () oracle com> wrote:
On 15 Jun 2020, at 11:26, Jason A. Donenfeld <Jason () zx2c4 com> wrote: Yesterday, I found a lockdown bypass in Ubuntu 18.04's kernel using ACPI table tricks via the efi ssdt variable [1]. Today I found another one that's a bit easier to exploit and appears to be unpatched on mainline, using acpi_configfs to inject an ACPI table. The tricks are basically the same as the first one, but this one appears to be unpatched, at least on my test machine. Explanation is in the header of the PoC: https://git.zx2c4.com/american-unsigned-language/tree/american-unsigned-language-2.sh I need to get some sleep, but if nobody posts a patch in the meanwhile, I'll try to post a fix tomorrow. Jason [1] https://www.openwall.com/lists/oss-security/2020/06/14/1This looks CVE-worthy. Are you going to ask for a CVE for it?
Does it really make sense to dole out CVEs for individual lockdown bypasses when various areas of the kernel (such as filesystems and BPF) don't see root->kernel privilege escalation issues as a problem? It's not like applying the fix for this one issue is going to make systems meaningfully safer.
Current thread:
- lockdown bypass on mainline kernel for loading unsigned modules Jason A. Donenfeld (Jun 15)
- Re: lockdown bypass on mainline kernel for loading unsigned modules John Haxby (Jun 15)
- Re: lockdown bypass on mainline kernel for loading unsigned modules Jann Horn (Jun 15)
- Re: lockdown bypass on mainline kernel for loading unsigned modules Jason A. Donenfeld (Jun 15)
- Re: lockdown bypass on mainline kernel for loading unsigned modules Jann Horn (Jun 15)
- Re: lockdown bypass on mainline kernel for loading unsigned modules Jason A. Donenfeld (Jun 15)
- Re: lockdown bypass on mainline kernel for loading unsigned modules John Haxby (Jun 15)