Commit ec06293134b85876f9201d8a52b844c41581b2b3

SECURITY FIX: DoS on EILSEQ in report_*() in -vv and multibyte-locales.
Makefile.am
(1 / 0)
  
126126 fetchmail-features.html README.SSL README.NTLM \
127127 README.packaging README.SSL-SERVER \
128128 fetchmail-FAQ.book fetchmail-FAQ.pdf fetchmail-FAQ.html \
129 fetchmail-SA-2010-02.txt \
129130 fetchmail-SA-2010-01.txt \
130131 fetchmail-SA-2009-01.txt \
131132 fetchmail-SA-2008-01.txt \
NEWS
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5454
5555fetchmail-6.3.17 (not yet released):
5656
57# SECURITY FIX
58* Fetchmail before release 6.3.17 did not properly sanitize external input
59 (mail headers and UID). When a multi-character locale (such as UTF-8) was in use,
60 this could cause memory exhaustion and thus a denial of service, because
61 fetchmail's report.c functions assumed that non-success of [v]snprintf was
62 due to insufficient buffer size allocation. It would then repeatedly reallocate
63 a larger buffer and fail formatting again. See fetchmail-SA-2010-02.txt.
64
5765# REGRESSION FIX
5866* Fix string handling in rcfile scanner, which caused fetchmail to misparse a
5967 run control file in certain circumstances. Fixes BerliOS bug #14257.
fetchmail-SA-2010-02.txt
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1- DRAFT - XXX - DRAFT -
2
3fetchmail-SA-2010-02: Denial of service in debug mode w/ multichar locales
4
5Topics: Denial of service in debug output.
6
7Author: Matthias Andree
8Version: 0.1 XXX
9Announced: XXX
10Type: malloc() Buffer overrun with printable characters
11Impact: Denial of service.
12Danger: low
13
14CVE Name: CVE-2010-XXXX
15CVSSv2: XXX
16URL: http://www.fetchmail.info/fetchmail-SA-2010-02.txt
17Project URL: http://www.fetchmail.info/
18
19Affects: fetchmail releases 4.6.3 up to and including 6.3.16
20
21Not affected: fetchmail release 6.3.17 and newer
22
23Corrected: 2010-04-18 Git (XXX)
24
25
260. Release history
27==================
28
292010-04-18 0.1 first draft (visible in SVN and through oss-security)
30XXX
31
32
331. Background
34=============
35
36fetchmail is a software package to retrieve mail from remote POP2, POP3,
37IMAP, ETRN or ODMR servers and forward it to local SMTP, LMTP servers or
38message delivery agents. It supports SSL and TLS security layers through
39the OpenSSL library, if enabled at compile time and if also enabled at
40run time.
41
42
432. Problem description and Impact
44=================================
45
46In debug mode (-v -v), fetchmail prints information that was obtained from the
47upstream server (POP3 UIDL lists) or from message headers retrieved from it.
48 If printing such information fails, for instance because there are invalid
49multibyte character sequences in this information (message headers), fetchmail
50will misinterpret this condition, and believe that the buffer was too small,
51and reallocate a bigger one (with linearly increasing buffer size), and repeat,
52until the allocation fails. At that point, fetchmail will abort.
53
54Note that the "Affects:" line above may be inaccurate, and it may be that
55versions before 5.6.6 are actually unaffected. The author was unable to
56compile such old fetchmail versions to verify the existence of the bug.
57 Given that other security issues are present in such versions, those should
58not be used, and the wider version range was listed as vulnerable to err
59towards the safe.
60
61
623. Solution
63===========
64
65There are two alternatives, either of them by itself is sufficient:
66
67a. Apply the patch found in section B of this announcement to
68 fetchmail 6.3.14 or newer, recompile and reinstall it.
69
70b. Install fetchmail 6.3.17 or newer after it will have become available.
71 The fetchmail source code is always available from
72 <http://developer.berlios.de/project/showfiles.php?group_id=1824>.
73
74
754. Workaround
76=============
77
78Run fetchmail with at most one -v (--verbose) option.
79
80
81A. Copyright, License and Warranty
82==================================
83
84(C) Copyright 2010 by Matthias Andree, <matthias.andree@gmx.de>.
85Some rights reserved.
86
87This work is licensed under the Creative Commons
88Attribution-Noncommercial-No Derivative Works 3.0 Germany License.
89To view a copy of this license, visit
90http://creativecommons.org/licenses/by-nc-nd/3.0/de/ or send a letter to
91
92Creative Commons
93171 Second Street
94Suite 300
95SAN FRANCISCO, CALIFORNIA 94105
96USA
97
98
99THIS WORK IS PROVIDED FREE OF CHARGE AND WITHOUT ANY WARRANTIES.
100Use the information herein at your own risk.
101
102
103B. Patch to remedy the problem
104==============================
105
106Note that when taking this from a GnuPG clearsigned file, the lines
107starting with a "-" character are prefixed by another "- " (dash +
108blank) combination. Either feed this file through GnuPG to strip them,
109or strip them manually. You may want to use the "-p1" flag to patch.
110
111Whitespace differences can usually be ignored by invoking "patch -l",
112so try this if the patch does not apply.
113
114diff --git a/rfc822.c b/rfc822.c
115index 6f2dbf3..dbcda32 100644
116--- a/rfc822.c
117+++ b/rfc822.c
118@@ -25,6 +25,7 @@ MIT license. Compile with -DMAIN to build the demonstrator.
119 #include <stdlib.h>
120
121 #include "fetchmail.h"
122+#include "sdump.h"
123
124 #ifndef MAIN
125 #include "i18n.h"
126@@ -74,9 +75,10 @@ char *reply_hack(
127 }
128
129 #ifndef MAIN
130- if (outlevel >= O_DEBUG)
131- report_build(stdout, GT_("About to rewrite %.*s...\n"),
132- (int)BEFORE_EOL(buf), buf);
133+ if (outlevel >= O_DEBUG) {
134+ report_build(stdout, GT_("About to rewrite %s...\n"), (cp = sdump(buf, BEFORE_EOL(buf))));
135+ xfree(cp);
136+ }
137
138 /* make room to hack the address; buf must be malloced */
139 for (cp = buf; *cp; cp++)
140@@ -211,9 +213,12 @@ char *reply_hack(
141 }
142
143 #ifndef MAIN
144- if (outlevel >= O_DEBUG)
145- report_complete(stdout, GT_("...rewritten version is %.*s.\n"),
146- (int)BEFORE_EOL(buf), buf);
147+ if (outlevel >= O_DEBUG) {
148+ report_complete(stdout, GT_("...rewritten version is %s.\n"),
149+ (cp = sdump(buf, BEFORE_EOL(buf))));
150+ xfree(cp)
151+ }
152+
153 #endif /* MAIN */
154 *length = strlen(buf);
155 return(buf);
156diff --git a/uid.c b/uid.c
157index fdc6f5d..d813bee 100644
158--- a/uid.c
159+++ b/uid.c
160@@ -20,6 +20,7 @@
161
162 #include "fetchmail.h"
163 #include "i18n.h"
164+#include "sdump.h"
165
166 /*
167 * Machinery for handling UID lists live here. This is mainly to support
168@@ -260,8 +261,11 @@ void initialize_saved_lists(struct query *hostlist, const char *idfile)
169 if (uidlcount)
170 {
171 report_build(stdout, GT_("Scratch list of UIDs:"));
172- for (idp = scratchlist; idp; idp = idp->next)
173- report_build(stdout, " %s", idp->id);
174+ for (idp = scratchlist; idp; idp = idp->next) {
175+ char *t = sdump(idp->id, strlen(idp->id));
176+ report_build(stdout, " %s", t);
177+ free(t);
178+ }
179 if (!idp)
180 report_build(stdout, GT_(" <empty>"));
181 report_complete(stdout, "\n");
182@@ -517,8 +521,11 @@ void uid_swap_lists(struct query *ctl)
183 report_build(stdout, GT_("Merged UID list from %s:"), ctl->server.pollname);
184 else
185 report_build(stdout, GT_("New UID list from %s:"), ctl->server.pollname);
186- for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp = idp->next)
187- report_build(stdout, " %s = %d", idp->id, idp->val.status.mark);
188+ for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp = idp->next) {
189+ char *t = sdump(idp->id, strlen(idp->id));
190+ report_build(stdout, " %s = %d", t, idp->val.status.mark);
191+ free(t);
192+ }
193 if (!idp)
194 report_build(stdout, GT_(" <empty>"));
195 report_complete(stdout, "\n");
196@@ -567,8 +574,11 @@ void uid_discard_new_list(struct query *ctl)
197 /* this is now a merged list! the mails which were seen in this
198 * poll are marked here. */
199 report_build(stdout, GT_("Merged UID list from %s:"), ctl->server.pollname);
200- for (idp = ctl->oldsaved; idp; idp = idp->next)
201- report_build(stdout, " %s = %d", idp->id, idp->val.status.mark);
202+ for (idp = ctl->oldsaved; idp; idp = idp->next) {
203+ char *t = sdump(idp->id, strlen(idp->id));
204+ report_build(stdout, " %s = %d", t, idp->val.status.mark);
205+ free(t);
206+ }
207 if (!idp)
208 report_build(stdout, GT_(" <empty>"));
209 report_complete(stdout, "\n");
rfc822.c
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2525#include <stdlib.h>
2626
2727#include "fetchmail.h"
28#include "sdump.h"
2829
2930#ifndef MAIN
3031#include "i18n.h"
……
7575 }
7676
7777#ifndef MAIN
78 if (outlevel >= O_DEBUG)
79 report_build(stdout, GT_("About to rewrite %.*s...\n"),
80 (int)BEFORE_EOL(buf), buf);
78 if (outlevel >= O_DEBUG) {
79 report_build(stdout, GT_("About to rewrite %s...\n"), (cp = sdump(buf, BEFORE_EOL(buf))));
80 xfree(cp);
81 }
8182
8283 /* make room to hack the address; buf must be malloced */
8384 for (cp = buf; *cp; cp++)
……
213213 }
214214
215215#ifndef MAIN
216 if (outlevel >= O_DEBUG)
217 report_complete(stdout, GT_("...rewritten version is %.*s.\n"),
218 (int)BEFORE_EOL(buf), buf);
216 if (outlevel >= O_DEBUG) {
217 report_complete(stdout, GT_("...rewritten version is %s.\n"),
218 (cp = sdump(buf, BEFORE_EOL(buf))));
219 xfree(cp)
220 }
221
219222#endif /* MAIN */
220223 *length = strlen(buf);
221224 return(buf);
uid.c
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2020
2121#include "fetchmail.h"
2222#include "i18n.h"
23#include "sdump.h"
2324
2425/*
2526 * Machinery for handling UID lists live here. This is mainly to support
……
261261 if (uidlcount)
262262 {
263263 report_build(stdout, GT_("Scratch list of UIDs:"));
264 for (idp = scratchlist; idp; idp = idp->next)
265 report_build(stdout, " %s", idp->id);
264 for (idp = scratchlist; idp; idp = idp->next) {
265 char *t = sdump(idp->id, strlen(idp->id));
266 report_build(stdout, " %s", t);
267 free(t);
268 }
266269 if (!idp)
267270 report_build(stdout, GT_(" <empty>"));
268271 report_complete(stdout, "\n");
……
521521 report_build(stdout, GT_("Merged UID list from %s:"), ctl->server.pollname);
522522 else
523523 report_build(stdout, GT_("New UID list from %s:"), ctl->server.pollname);
524 for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp = idp->next)
525 report_build(stdout, " %s = %d", idp->id, idp->val.status.mark);
524 for (idp = dofastuidl ? ctl->oldsaved : ctl->newsaved; idp; idp = idp->next) {
525 char *t = sdump(idp->id, strlen(idp->id));
526 report_build(stdout, " %s = %d", t, idp->val.status.mark);
527 free(t);
528 }
526529 if (!idp)
527530 report_build(stdout, GT_(" <empty>"));
528531 report_complete(stdout, "\n");
……
574574 /* this is now a merged list! the mails which were seen in this
575575 * poll are marked here. */
576576 report_build(stdout, GT_("Merged UID list from %s:"), ctl->server.pollname);
577 for (idp = ctl->oldsaved; idp; idp = idp->next)
578 report_build(stdout, " %s = %d", idp->id, idp->val.status.mark);
577 for (idp = ctl->oldsaved; idp; idp = idp->next) {
578 char *t = sdump(idp->id, strlen(idp->id));
579 report_build(stdout, " %s = %d", t, idp->val.status.mark);
580 free(t);
581 }
579582 if (!idp)
580583 report_build(stdout, GT_(" <empty>"));
581584 report_complete(stdout, "\n");