From owner-freebsd-bugs Thu Nov 25 5:40: 4 1999 Delivered-To: freebsd-bugs@freebsd.org Received: from freefall.freebsd.org (freefall.FreeBSD.ORG [204.216.27.21]) by hub.freebsd.org (Postfix) with ESMTP id 0EEFB14E0E for ; Thu, 25 Nov 1999 05:40:01 -0800 (PST) (envelope-from gnats@FreeBSD.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.9.3/8.9.2) id FAA58660; Thu, 25 Nov 1999 05:40:00 -0800 (PST) (envelope-from gnats@FreeBSD.org) Received: from point.osg.gov.bc.ca (point.osg.gov.bc.ca [142.32.102.44]) by hub.freebsd.org (Postfix) with ESMTP id 7850514E0F for ; Thu, 25 Nov 1999 05:30:23 -0800 (PST) (envelope-from cy@cschuber.net.gov.bc.ca) Received: (from daemon@localhost) by point.osg.gov.bc.ca (8.8.7/8.8.8) id FAA11993 for ; Thu, 25 Nov 1999 05:30:22 -0800 Received: from cschuber.net.gov.bc.ca(142.31.240.113), claiming to be "cwsys.cwsent.com" via SMTP by point.osg.gov.bc.ca, id smtpda11991; Thu Nov 25 05:30:18 1999 Received: (from cy@localhost) by cwsys.cwsent.com (8.9.3/8.9.1) id FAA06829; Thu, 25 Nov 1999 05:30:16 -0800 (PST) Message-Id: <199911251330.FAA06829@cwsys.cwsent.com> Date: Thu, 25 Nov 1999 05:30:16 -0800 (PST) From: Cy.Schubert@uumail.gov.bc.ca Reply-To: Cy.Schubert@uumail.gov.bc.ca To: FreeBSD-gnats-submit@freebsd.org X-Send-Pr-Version: 3.2 Subject: bin/15088: Sendmail 8.9.3 Patch Sender: owner-freebsd-bugs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org >Number: 15088 >Category: bin >Synopsis: Sendmail patch >Confidential: no >Severity: critical >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Nov 25 05:40:00 PST 1999 >Closed-Date: >Last-Modified: >Originator: Cy Schubert >Release: FreeBSD 3.3-STABLE i386 >Organization: ITSD Province of BC >Environment: FreeBSD cwsys 3.3-STABLE FreeBSD 3.3-STABLE #0: Wed Nov 24 18:59:43 PST 1999 root@:/opt2/cvs-330S/src/sys/compile/CWSYS i386 >Description: The following was posted on bugtraq: Date: Mon, 22 Nov 1999 23:48:17 -0800 Reply-To: Gregory Neil Shapiro Sender: Bugtraq List From: Gregory Neil Shapiro Subject: Re: Sendmail 8.x.x - any user may rebuild aliases database X-To: Michal Zalewski X-cc: BUGTRAQ@SECURITYFOCUS.COM, sendmail-bugs@sendmail.org To: BUGTRAQ@SECURITYFOCUS.COM In-Reply-To: X-UIDL: d3d08b1a16cd01ca35681b18bae9ed46 -----BEGIN PGP SIGNED MESSAGE----- lcamtuf> Sendmail up to recent 8.9.x versions - any user may pass -bi lcamtuf> parameter to /usr/sbin/sendmail. This will result in aliases lcamtuf> database rebuild. IMHO there's no reason to allow such things, but lcamtuf> no matter - something rather stupid is done during rebuild: lcamtuf> 5366 open("/etc/aliases.db", O_RDWR|O_TRUNC) = 6 lcamtuf> What a bad luck! There's approx 0.1 sec delay due to /etc/aliases lcamtuf> processing (on my system). Meantime, luser might deliver any lcamtuf> signals to sendmail process... SIGKILL is quite good. After that, lcamtuf> /etc/aliases.db will be left in unusable state (no EOF marker), lcamtuf> causing DoS: Thank you for bringing this to our attention. We have limited the newaliases command to root and trusted users for 8.10.0.Beta7. We have also deprecated the AutoRebuildAliases option since if set, a similar attack may be possible. We intend to remove the AutoRebuildAliases functionality in a future version. I've included a patch against sendmail 8.9.3 for those who want to protect against this denial of service attack. As always, we encourage mailing bug reports, including documentation or release notes bugs, to sendmail-bugs@sendmail.org. Security issues can be mailed to sendmail-security@sendmail.org and encrypted with the sendmail-security@sendmail.org PGP key: Type Bits KeyID Created Expires Algorithm Use pub 1024 0x16F4CCE9 1999-06-23 ---------- RSA Sign & Encrypt uid Sendmail Security The sendmail 8.9.3 patch: --- main.c~orig Sat Jan 9 15:31:13 1999 +++ main.c Wed Nov 17 19:04:44 1999 @@ -984,6 +984,18 @@ usrerr("Permission denied"); finis(FALSE, EX_USAGE); } + if (OpMode == MD_INITALIAS && + RealUid != 0 && + RealUid != TrustedUid && + !wordinclass(RealUserName, 't')) + { + if (LogLevel > 1) + sm_syslog(LOG_ALERT, NOQID, + "user %d attempted to rebuild the alias map", + RealUid); + usrerr("Permission denied"); + finis(FALSE, EX_USAGE); + } if (MeToo) BlankEnvelope.e_flags |= EF_METOO; >How-To-Repeat: See description. >Fix: See patch posted by Gregory Shapiro of sendmail.org to BUGTRAQ above. It would be nice to have this committed before 3.4 is released. You may wish to remove the AutoRebuildAliases option too. >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message