FreeBSD Security Advisories
2014-Dec-10 17:16 UTC
FreeBSD Security Advisory FreeBSD-SA-14:27.stdio
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================FreeBSD-SA-14:27.stdio Security Advisory The FreeBSD Project Topic: Buffer overflow in stdio Category: core Module: libc Announced: 2014-12-10 Credits: Adrian Chadd and Alfred Perlstein, Norse Corporation Affects: FreeBSD 10.1 Corrected: 2014-12-10 08:24:02 UTC (stable/10, 10.1-STABLE) 2014-12-10 08:35:55 UTC (releng/10.1, 10.1-RELEASE-p1) CVE Name: CVE-2014-8611 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://security.FreeBSD.org/>. I. Background The standard I/O library provides a simple and efficient buffered stream I/O interface. The library writes buffered data when it is full or when the application explicitly request so by calling the fflush(3) function. II. Problem Description A programming error in the standard I/O library's __sflush() function could erroneously adjust the buffered stream's internal state even when no write actually occurred in the case when write(2) system call returns an error. III. Impact The accounting mismatch would accumulate, if the caller does not check for stream status and will eventually lead to a heap buffer overflow. Such overflows may lead to data corruption or the execution of arbitrary code at the privilege level of the calling program. IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 2) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install 3) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-14:27/stdio.patch # fetch http://security.FreeBSD.org/patches/SA-14:27/stdio.patch.asc # gpg --verify stdio.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in <URL:http://www.FreeBSD.org/handbook/makeworld.html>. Reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/10/ r275667 releng/10.1/ r275670 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-8611> The latest revision of this advisory is available at <URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:27.stdio.asc> -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJUiA11AAoJEO1n7NZdz2rnZLMP/ic0j0lykvkZ4x39Th4vUIX7 SCqROB8zxKj8qA3QlXhusaJA9o9hAPX8HA99ZVbDyugz0m4ST0t6JAYL+w3eVYZm RpEszshxi7rwUXaoue99lk0JnP2ssZbNZn5y4Z0XCYvingfP7Um6tOG0XqUs+N45 Mivhuz+JKaFSYG4WwrSIr2pNpn6XnDeGoihtuXOkinBv8Ga3xHyuTY+30vUnEEH+ Vr2MftHMm3Wo87OM1XhrTQS5jYzD8u0xgwKjcf0/+6Q+iXzLDkk8MfCE1W9SP7FE zas1MHxWeV5AICAX0CUI/9R2Zgymi/xJksw4BNZsDyGnOvIRdcMv+0KOWnCn42mk HCm2NTyvUM2Cgjbj5T4yICQBEi5dI6WiTp2yKTKQOiqDsszUW1NyqGQdYPfyjjMS kQA5RTdGVxwxp8FMnJGvYdlVRZgx5BAI8znhlxxqKs25uhbOnn+zKm+rA2XnLLMk sg2V/E906vldjLw8ddvNKm5oy0UkezBj0J1NOgkpN3atvUB8X2H251h2n51+oAbE FSd4qqN70vwHdOmIGNrjWZpOqSJzeGs5JjbaxMpo6MoIWJz2zrK2WLiFVWZGohgh 9TGU6Ubs/yTLLfu1jTDAMl1dbZd1lChmycKRuqTpe56keOlHghquCMxhogWY0PQE nE47N3BP/KCtuQw1uxuK =F9uH -----END PGP SIGNATURE-----