ftp,imap,pop3,smtp: reject STARTTLS server response pipelining

If a server pipelines future responses within the STARTTLS response, the
former are preserved in the pingpong cache across TLS negotiation and
used as responses to the encrypted commands.

This fix detects pipelined STARTTLS responses and rejects them with an
error.

CVE-2021-22947

Bug: https://curl.se/docs/CVE-2021-22947.html
This commit is contained in:
Patrick Monnerat 2021-09-07 13:26:42 +02:00 коммит произвёл Daniel Stenberg
Родитель 364f174724
Коммит 8ef147c436
Не найден ключ, соответствующий данной подписи
Идентификатор ключа GPG: 5CC908FDB71E12C2
9 изменённых файлов: 236 добавлений и 1 удалений

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@ -2743,6 +2743,9 @@ static CURLcode ftp_statemachine(struct Curl_easy *data,
case FTP_AUTH:
/* we have gotten the response to a previous AUTH command */
if(pp->cache_size)
return CURLE_WEIRD_SERVER_REPLY; /* Forbid pipelining in response. */
/* RFC2228 (page 5) says:
*
* If the server is willing to accept the named security mechanism,

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@ -963,6 +963,10 @@ static CURLcode imap_state_starttls_resp(struct Curl_easy *data,
(void)instate; /* no use for this yet */
/* Pipelining in response is forbidden. */
if(data->conn->proto.imapc.pp.cache_size)
return CURLE_WEIRD_SERVER_REPLY;
if(imapcode != IMAP_RESP_OK) {
if(data->set.use_ssl != CURLUSESSL_TRY) {
failf(data, "STARTTLS denied");

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@ -771,6 +771,10 @@ static CURLcode pop3_state_starttls_resp(struct Curl_easy *data,
CURLcode result = CURLE_OK;
(void)instate; /* no use for this yet */
/* Pipelining in response is forbidden. */
if(data->conn->proto.pop3c.pp.cache_size)
return CURLE_WEIRD_SERVER_REPLY;
if(pop3code != '+') {
if(data->set.use_ssl != CURLUSESSL_TRY) {
failf(data, "STARTTLS denied");

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@ -834,6 +834,10 @@ static CURLcode smtp_state_starttls_resp(struct Curl_easy *data,
CURLcode result = CURLE_OK;
(void)instate; /* no use for this yet */
/* Pipelining in response is forbidden. */
if(data->conn->proto.smtpc.pp.cache_size)
return CURLE_WEIRD_SERVER_REPLY;
if(smtpcode != 220) {
if(data->set.use_ssl != CURLUSESSL_TRY) {
failf(data, "STARTTLS denied, code %d", smtpcode);

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@ -118,7 +118,7 @@ test954 test955 test956 test957 test958 test959 test960 test961 test962 \
test963 test964 test965 test966 test967 test968 test969 test970 test971 \
test972 \
\
test984 test985 test986 \
test980 test981 test982 test983 test984 test985 test986 \
\
test1000 test1001 test1002 test1003 test1004 test1005 test1006 test1007 \
test1008 test1009 test1010 test1011 test1012 test1013 test1014 test1015 \

52
tests/data/test980 Normal file
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@ -0,0 +1,52 @@
<testcase>
<info>
<keywords>
SMTP
STARTTLS
</keywords>
</info>
#
# Server-side
<reply>
<servercmd>
CAPA STARTTLS
AUTH PLAIN
REPLY STARTTLS 454 currently unavailable\r\n235 Authenticated\r\n250 2.1.0 Sender ok\r\n250 2.1.5 Recipient ok\r\n354 Enter mail\r\n250 2.0.0 Accepted
REPLY AUTH 535 5.7.8 Authentication credentials invalid
</servercmd>
</reply>
#
# Client-side
<client>
<features>
SSL
</features>
<server>
smtp
</server>
<name>
SMTP STARTTLS pipelined server response
</name>
<stdin>
mail body
</stdin>
<command>
smtp://%HOSTIP:%SMTPPORT/%TESTNUMBER --mail-rcpt recipient@example.com --mail-from sender@example.com -u user:secret --ssl --sasl-ir -T -
</command>
</client>
#
# Verify data after the test has been "shot"
<verify>
# 8 is CURLE_WEIRD_SERVER_REPLY
<errorcode>
8
</errorcode>
<protocol>
EHLO %TESTNUMBER
STARTTLS
</protocol>
</verify>
</testcase>

59
tests/data/test981 Normal file
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@ -0,0 +1,59 @@
<testcase>
<info>
<keywords>
IMAP
STARTTLS
</keywords>
</info>
#
# Server-side
<reply>
<servercmd>
CAPA STARTTLS
REPLY STARTTLS A002 BAD currently unavailable\r\nA003 OK Authenticated\r\nA004 OK Accepted
REPLY LOGIN A003 BAD Authentication credentials invalid
</servercmd>
</reply>
#
# Client-side
<client>
<features>
SSL
</features>
<server>
imap
</server>
<name>
IMAP STARTTLS pipelined server response
</name>
<command>
imap://%HOSTIP:%IMAPPORT/%TESTNUMBER -T log/upload%TESTNUMBER -u user:secret --ssl
</command>
<file name="log/upload%TESTNUMBER">
Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
From: Fred Foobar <foobar@example.COM>
Subject: afternoon meeting
To: joe@example.com
Message-Id: <B27397-0100000@example.COM>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
Hello Joe, do you think we can meet at 3:30 tomorrow?
</file>
</client>
#
# Verify data after the test has been "shot"
<verify>
# 8 is CURLE_WEIRD_SERVER_REPLY
<errorcode>
8
</errorcode>
<protocol>
A001 CAPABILITY
A002 STARTTLS
</protocol>
</verify>
</testcase>

57
tests/data/test982 Normal file
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@ -0,0 +1,57 @@
<testcase>
<info>
<keywords>
POP3
STARTTLS
</keywords>
</info>
#
# Server-side
<reply>
<servercmd>
CAPA STLS USER
REPLY STLS -ERR currently unavailable\r\n+OK user accepted\r\n+OK authenticated
REPLY PASS -ERR Authentication credentials invalid
</servercmd>
<data nocheck="yes">
From: me@somewhere
To: fake@nowhere
body
--
yours sincerely
</data>
</reply>
#
# Client-side
<client>
<features>
SSL
</features>
<server>
pop3
</server>
<name>
POP3 STARTTLS pipelined server response
</name>
<command>
pop3://%HOSTIP:%POP3PORT/%TESTNUMBER -u user:secret --ssl
</command>
</client>
#
# Verify data after the test has been "shot"
<verify>
# 8 is CURLE_WEIRD_SERVER_REPLY
<errorcode>
8
</errorcode>
<protocol>
CAPA
STLS
</protocol>
</verify>
</testcase>

52
tests/data/test983 Normal file
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@ -0,0 +1,52 @@
<testcase>
<info>
<keywords>
FTP
STARTTLS
</keywords>
</info>
#
# Server-side
<reply>
<servercmd>
REPLY AUTH 500 unknown command\r\n500 unknown command\r\n331 give password\r\n230 Authenticated\r\n257 "/"\r\n200 OK\r\n200 OK\r\n200 OK\r\n226 Transfer complete
REPLY PASS 530 Login incorrect
</servercmd>
</reply>
# Client-side
<client>
<features>
SSL
</features>
<server>
ftp
</server>
<name>
FTP STARTTLS pipelined server response
</name>
<file name="log/test%TESTNUMBER.txt">
data
to
see
that FTPS
works
so does it?
</file>
<command>
--ssl --ftp-ssl-control ftp://%HOSTIP:%FTPPORT/%TESTNUMBER -T log/test%TESTNUMBER.txt -u user:secret -P %CLIENTIP
</command>
</client>
# Verify data after the test has been "shot"
<verify>
# 8 is CURLE_WEIRD_SERVER_REPLY
<errorcode>
8
</errorcode>
<protocol>
AUTH SSL
</protocol>
</verify>
</testcase>