Bug#4332: Vulnerability in the Xt library (fwd)
Package: xlib
Version: 3.1.2-7
It seems there is a buffer overrun in libXt, which may be a security
hole (some programs using libXt, such as xterm, are setuid root).
I haven't tried to exploit it, but xterm -fg very_long_string
segfaults, so it might be exploitable (stack overwrite). See the
attached message (which appeared on the bugtraq list) for a patch.
I haven't verified that the fix is indeed in XFree86-3.1.2F (just
released) - can't get to ftp.xfree86.org right now (too many users)
and can't find this version on mirror sites yet.
Marek
> Date: Sun, 25 Aug 1996 22:05:16 -0700
> From: Ollivier Robert <roberto%keltia.freenix.fr@plearn.edu.pl>
> Subject: Re: Vulnerability in the Xt library (fwd)
> To: Multiple recipients of list BUGTRAQ <BUGTRAQ@NETSPACE.ORG>
> According to John Capo:
> > Stefan `Sec` Zehl writes:
> > > I can confirm this for Freebsd 2.2-Current, it gives me a euid=0 /bin/sh
>
> > I can also. The xterm cores on -stable though.
>
> I sent a patch and a portable version of snprintf to both the X consortium
> and Xfree86 yesterday. It will be in 3.1.2F.
>
> If you have XFree sources on-line and are willing to recompile, apply the
> following patch in xc/lib/Xt:
>
> --- Error.c.old Sun Aug 25 14:57:28 1996
> +++ Error.c Sun Aug 25 14:47:14 1996
> @@ -238,5 +238,5 @@
> (void) memmove((char*)par, (char*)params, i * sizeof(String) );
> bzero( &par[i], (10-i) * sizeof(String) );
> - (void) sprintf(message, buffer, par[0], par[1], par[2], par[3],
> + (void) snprintf(message, sizeof message, buffer, par[0], par[1], par[2], par[3],
> par[4], par[5], par[6], par[7], par[8], par[9]);
> XtError(message);
> @@ -263,5 +263,5 @@
> (void) memmove((char*)par, (char*)params, i * sizeof(String) );
> bzero ( &par[i], (10-i) * sizeof(String) );
> - (void) sprintf(message, buffer, par[0], par[1], par[2], par[3],
> + (void) snprintf(message, sizeof message, buffer, par[0], par[1], par[2], par[3],
> par[4], par[5], par[6], par[7], par[8], par[9]);
> XtWarning(message);
>
> --
> Ollivier ROBERT -=- The daemon is FREE! -=- roberto@keltia.freenix.fr
> FreeBSD keltia.freenix.fr 2.2-CURRENT #18: Sun Aug 18 19:16:52 MET DST 1996
>
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