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FreeBSD Security Advisory FreeBSD-SA-02:38.signed-error


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Date: Mon, 19 Aug 2002 05:56:22 -0700 (PDT)
From: FreeBSD Security Advisories <security-advisories@freebsd.org.>
To: Bugtraq <bugtraq@securityfocus.com.>
Subject: FreeBSD Security Advisory FreeBSD-SA-02:38.signed-error

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FreeBSD-SA-02:38.signed-error Security Advisory The FreeBSD Project Topic: Boundary checking errors involving signed integers Category: core Module: sys Announced: 2002-08-19 Credits: Silvio Cesare <silvio@qualys.com.> Affects: All releases of FreeBSD up to and including 4.6.1-RELEASE-p10 Corrected: 2002-08-13 02:42:32 UTC (RELENG_4) 2002-08-13 12:12:36 UTC (RELENG_4_6) 2002-08-13 12:13:05 UTC (RELENG_4_5) 2002-08-13 12:13:49 UTC (RELENG_4_4) FreeBSD only: YES I. Background The issue described in this advisory affects the accept(2), getsockname(2), and getpeername(2) system calls, and the vesa(4) FBIO_GETPALETTE ioctl(2). II. Problem Description A few system calls were identified that contained assumptions that a given argument was always a positive integer, while in fact the argument was handled as a signed integer. As a result, the boundary checking code would fail if the system call were entered with a negative argument. III. Impact The affected system calls could be called with large negative arguments, causing the kernel to return a large portion of kernel memory. Such memory might contain sensitive information, such as portions of the file cache or terminal buffers. This information might be directly useful, or it might be leveraged to obtain elevated privileges in some way. For example, a terminal buffer might include a user-entered password. IV. Workaround None. V. Solution 1) Upgrade your vulnerable system to 4.6.2-RELEASE or 4.6-STABLE; or to any of the RELENG_4_6 (4.6.1-RELEASE-p11), RELENG_4_5 (4.5-RELEASE-p19), or RELENG_4_4 (4.4-RELEASE-p26) security branches dated after the respective correction dates. 2) To patch your present system: a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. The following patch has been tested to apply to all FreeBSD 4.x releases. # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:38/signed-error.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:38/signed-error.patch.asc b) Apply the patch. # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:http://www.freebsd.org/handbook/kernelconfig.html>; and reboot the system. VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Path Revision Branch - ------------------------------------------------------------------------- src/sys/i386/isa/vesa.c RELENG_4 1.32.2.1 RELENG_4_6 1.32.10.1 RELENG_4_5 1.32.8.1 RELENG_4_4 1.32.6.1 src/sys/kern/uipc_syscalls.c RELENG_4 1.65.2.12 RELENG_4_6 1.65.2.9.6.1 RELENG_4_5 1.65.2.9.4.1 RELENG_4_4 1.65.2.9.2.1 src/sys/conf/newvers.sh RELENG_4_6 1.44.2.23.2.16 RELENG_4_5 1.44.2.20.2.20 RELENG_4_4 1.44.2.17.2.25 - ------------------------------------------------------------------------- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.7 (FreeBSD) iQCVAwUBPWDpxFUuHi5z0oilAQHCWgP+PmomqbDBiBHKG6JWrx8Kz8M6gnrg4omw w/vH5uK2lHGL6ZGecwvhJOTbV4bKXt1C1dKoUyA7WH7l9nQi+1CrZwT/D5mkteU+ XEqtNfRhiaDokj/5I8MA0OM80+jryeAimxYDEi2vm315RIOMeR/sdP7m7H2vl9cZ V8rt/2zD2wc= =LpMd -----END PGP SIGNATURE-----

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