linux-kernel - Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 10 May 2021 16:14:44 -0500
From:   Segher Boessenkool <segher@...nel.crashing.org>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, pmenzel@...gen.mpg.de,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

On Sat, May 08, 2021 at 06:36:21AM +0000, Christophe Leroy wrote:
> UBSAN complains when a pointer is calculated with invalid
> 'legacy_serial_console' index, allthough the index is verified
> before dereferencing the pointer.

Addressing like this is UB already.

You could just move this:

> -	if (legacy_serial_console < 0)
> -		return 0;

to before

> -	struct legacy_serial_info *info = &legacy_serial_infos[legacy_serial_console];
> -	struct plat_serial8250_port *port = &legacy_serial_ports[legacy_serial_console];

and no other change is necessary.


Segher