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Date: Mon, 19 Apr 2010 15:36:21 -0400 (EDT)
From: Josh Bressers <bressers@...hat.com>
To: oss-security@...ts.openwall.com
Subject: Re: CVE request: fetchmail 4.6.3...6.3.16 DoS in -v
-v mode in multibyte locales on invalid input
So even though the cause may be different, it's still a DoS, so let's use
CVE-2010-1167
Thanks.
--
JB
----- "Matthias Andree" <matthias.andree@....de> wrote:
> Please assign a CVE id for the issue described below. (Best viewed in
>
> non-proportional font with 8 space tabs):
>
>
> Draft announcement:
>
> - DRAFT - XXX - DRAFT -
>
> fetchmail-SA-2010-02: Denial of service in debug mode w/ multichar
> locales
>
> Topics: Denial of service in debug output.
>
> Author: Matthias Andree
> Version: 0.1 XXX
> Announced: XXX
> Type: malloc() Buffer overrun with printable characters
> Impact: Denial of service.
> Danger: low
>
> CVE Name: CVE-2010-XXXX
> CVSSv2: XXX
> URL: http://www.fetchmail.info/fetchmail-SA-2010-02.txt
> Project URL: http://www.fetchmail.info/
>
> Affects: fetchmail releases 4.6.3 up to and including 6.3.16
>
> Not affected: fetchmail release 6.3.17 and newer
>
> Corrected: 2010-04-18 Git (XXX)
>
>
> 0. Release history
> ==================
>
> 2010-04-18 0.1 first draft (visible in SVN and through oss-security)
> XXX
>
>
> 1. Background
> =============
>
> fetchmail is a software package to retrieve mail from remote POP2,
> POP3,
> IMAP, ETRN or ODMR servers and forward it to local SMTP, LMTP servers
> or
> message delivery agents. It supports SSL and TLS security layers
> through
> the OpenSSL library, if enabled at compile time and if also enabled
> at
> run time.
>
>
> 2. Problem description and Impact
> =================================
>
> In debug mode (-v -v), fetchmail prints information that was obtained
> from
> the
> upstream server (POP3 UIDL lists) or from message headers retrieved
> from
> it.
> If printing such information fails, for instance because there are
>
> invalid
> multibyte character sequences in this information (message headers),
>
> fetchmail
> will misinterpret this condition, and believe that the buffer was too
>
> small,
> and reallocate a bigger one (with linearly increasing buffer size),
> and
> repeat,
> until the allocation fails. At that point, fetchmail will abort.
>
> Note that the "Affects:" line above may be inaccurate, and it may be
> that
> versions before 5.6.6 are actually unaffected. The author was unable
> to
> compile such old fetchmail versions to verify the existence of the
> bug.
> Given that other security issues are present in such versions,
> those
> should
> not be used, and the wider version range was listed as vulnerable to
> err
> towards the safe.
>
>
> 3. Solution
> ===========
>
> There are two alternatives, either of them by itself is sufficient:
>
> a. Apply the patch found in section B of this announcement to
> fetchmail 6.3.14 or newer, recompile and reinstall it.
>
> b. Install fetchmail 6.3.17 or newer after it will have become
> available.
> The fetchmail source code is always available from
>
> <http://developer.berlios.de/project/showfiles.php?group_id=1824>.
>
>
> 4. Workaround
> =============
>
> Run fetchmail with at most one -v (--verbose) option.
>
>
> A. Copyright, License and Warranty
> ==================================
>
> (C) Copyright 2010 by Matthias Andree, <matthias.andree@....de>.
> Some rights reserved.
>
> This work is licensed under the Creative Commons
> Attribution-Noncommercial-No Derivative Works 3.0 Germany License.
> To view a copy of this license, visit
> http://creativecommons.org/licenses/by-nc-nd/3.0/de/ or send a letter
> to
>
> Creative Commons
> 171 Second Street
> Suite 300
> SAN FRANCISCO, CALIFORNIA 94105
> USA
>
>
> THIS WORK IS PROVIDED FREE OF CHARGE AND WITHOUT ANY WARRANTIES.
> Use the information herein at your own risk.
>
>
> B. Patch to remedy the problem
> ==============================
>
> Note that when taking this from a GnuPG clearsigned file, the lines
> starting with a "-" character are prefixed by another "- " (dash +
> blank) combination. Either feed this file through GnuPG to strip
> them,
> or strip them manually. You may want to use the "-p1" flag to patch.
>
> Whitespace differences can usually be ignored by invoking "patch -l",
> so try this if the patch does not apply.
>
> diff --git a/rfc822.c b/rfc822.c
> index 6f2dbf3..dbcda32 100644
> --- a/rfc822.c
> +++ b/rfc822.c
> @@ -25,6 +25,7 @@ MIT license. Compile with -DMAIN to build the
> demonstrator.
> #include <stdlib.h>
>
> #include "fetchmail.h"
> +#include "sdump.h"
>
> #ifndef MAIN
> #include "i18n.h"
> @@ -74,9 +75,10 @@ char *reply_hack(
> }
>
> #ifndef MAIN
> - if (outlevel >= O_DEBUG)
> - report_build(stdout, GT_("About to rewrite %.*s...\n"),
> - (int)BEFORE_EOL(buf), buf);
> + if (outlevel >= O_DEBUG) {
> + report_build(stdout, GT_("About to rewrite %s...\n"), (cp =
> sdump(buf,
> BEFORE_EOL(buf))));
> + xfree(cp);
> + }
>
> /* make room to hack the address; buf must be malloced */
> for (cp = buf; *cp; cp++)
> @@ -211,9 +213,12 @@ char *reply_hack(
> }
>
> #ifndef MAIN
> - if (outlevel >= O_DEBUG)
> - report_complete(stdout, GT_("...rewritten version is %.*s.\n"),
> - (int)BEFORE_EOL(buf), buf);
> + if (outlevel >= O_DEBUG) {
> + report_complete(stdout, GT_("...rewritten version is %s.\n"),
> + (cp = sdump(buf, BEFORE_EOL(buf))));
> + xfree(cp)
> + }
> +
> #endif /* MAIN */
> *length = strlen(buf);
> return(buf);
> diff --git a/uid.c b/uid.c
> index fdc6f5d..d813bee 100644
> --- a/uid.c
> +++ b/uid.c
> @@ -20,6 +20,7 @@
>
> #include "fetchmail.h"
> #include "i18n.h"
> +#include "sdump.h"
>
> /*
> * Machinery for handling UID lists live here. This is mainly to
> support
> @@ -260,8 +261,11 @@ void initialize_saved_lists(struct query
> *hostlist,
> const char *idfile)
> if (uidlcount)
> {
> report_build(stdout, GT_("Scratch list of UIDs:"));
> - for (idp = scratchlist; idp; idp = idp->next)
> - report_build(stdout, " %s", idp->id);
> + for (idp = scratchlist; idp; idp = idp->next) {
> + char *t = sdump(idp->id, strlen(idp->id));
> + report_build(stdout, " %s", t);
> + free(t);
> + }
> if (!idp)
> report_build(stdout, GT_(" <empty>"));
> report_complete(stdout, "\n");
> @@ -517,8 +521,11 @@ void uid_swap_lists(struct query *ctl)
> report_build(stdout, GT_("Merged UID list from %s:"),
> ctl->server.pollname);
> else
> report_build(stdout, GT_("New UID list from %s:"),
> ctl->server.pollname);
> - for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp =
> idp->next)
> - report_build(stdout, " %s = %d", idp->id,
> idp->val.status.mark);
> + for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp =
> idp->next) {
> + char *t = sdump(idp->id, strlen(idp->id));
> + report_build(stdout, " %s = %d", t, idp->val.status.mark);
> + free(t);
> + }
> if (!idp)
> report_build(stdout, GT_(" <empty>"));
> report_complete(stdout, "\n");
> @@ -567,8 +574,11 @@ void uid_discard_new_list(struct query *ctl)
> /* this is now a merged list! the mails which were seen in this
> * poll are marked here. */
> report_build(stdout, GT_("Merged UID list from %s:"),
> ctl->server.pollname);
> - for (idp = ctl->oldsaved; idp; idp = idp->next)
> - report_build(stdout, " %s = %d", idp->id,
> idp->val.status.mark);
> + for (idp = ctl->oldsaved; idp; idp = idp->next) {
> + char *t = sdump(idp->id, strlen(idp->id));
> + report_build(stdout, " %s = %d", t, idp->val.status.mark);
> + free(t);
> + }
> if (!idp)
> report_build(stdout, GT_(" <empty>"));
> report_complete(stdout, "\n");
>
>
>
> --
> Matthias Andree
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