http://bugzilla.novell.com/show_bug.cgi?id=597673 http://bugzilla.novell.com/show_bug.cgi?id=597673#c0 Summary: fetchmail: DoS in -v -v mode in multibyte Classification: openSUSE Product: openSUSE 11.3 Version: Factory Platform: Other OS/Version: Other Status: NEW Severity: Normal Priority: P5 - None Component: Security AssignedTo: puzel@novell.com ReportedBy: lnussel@novell.com QAContact: qa@suse.de CC: security-team@suse.de Found By: Other Blocker: --- Your friendly security team received the following report via oss-security. Please respond ASAP. The issue is public. Factory only sufficient ------------------------------------------------------------------------------ Date: Sun, 18 Apr 2010 18:58:30 +0200 From: "Matthias Andree" <matthias.andree@gmx.de> Subject: [oss-security] CVE request: fetchmail 4.6.3...6.3.16 DoS in -v -v mode in multibyte locales on invalid input 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@gmx.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 -- Configure bugmail: http://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.