Re: New Linux LPE via GSMIOC_SETCONF_DLCI?

["Dr. Christopher Kunz" <info () christopher-kunz de>]

Hi,

> There are two exploits in Yurii's repo above, according to Yurii for two
> different bugs.  The above is one of them.  Perhaps also try the other?
The two exploit versions are for different kernels. The 6.5 exploit 
doesn't compile on the Debian 12 6.1 kernel, and no Debian version 
currently distributes a 6.5 kernel, AFAICT. I used 
ExploitGSM_5_15_to_6_1/ExploitGSM and it worked.
> I don't know, and apparently it'd need to be two CVEs for two bugs that
> Yurii exploits.
Possibly. I'm definitely out of my depth trying to analyze which bugs 
are being exploited.
> CVE-2023-52564: Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux"
> https://lists.openwall.net/linux-cve-announce/2024/03/02/54
>
> Maybe CVE-2023-52564 is one of the bugs Yurii exploits, or maybe not.
> I didn't look into this closely enough to tell.

Apparently not. Debian 12 "Bookworm" currently runs this kernel:

Linux debianexploitgsm 6.1.0-18-amd64 #1 SMP PREEMPT_DYNAMIC Debian 
6.1.76-1 (2024-02-01) x86_64 GNU/Linux

According to the changelog, this kernel has the fix for CVE-2023-52564 
included:
    - Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux"
(from 
https://metadata.ftp-master.debian.org/changelogs//main/l/linux-signed-amd64/linux-signed-amd64_6.1.76+1_changelog)

Still, the exploit works, so it must exploit a different issue.

Just my two cents,

--cku