Backport of:
From 96d71feb27e533a8b337512841a537952916262c Mon Sep 17 00:00:00 2001
From: Patrick Monnerat <patrick@monnerat.net>
Date: Wed, 8 Sep 2021 11:56:22 +0200
Subject: [PATCH] ftp,imap,pop3: do not ignore --ssl-reqd
In imap and pop3, check if TLS is required even when capabilities
request has failed.
In ftp, ignore preauthentication (230 status of server greeting) if TLS
is required.
Bug: https://curl.se/docs/CVE-2021-22946.html
CVE-2021-22946
---
lib/ftp.c | 9 ++++---
lib/imap.c | 24 ++++++++----------
lib/pop3.c | 33 +++++++++++-------------
tests/data/Makefile.inc | 2 ++
tests/data/test984 | 56 +++++++++++++++++++++++++++++++++++++++++
tests/data/test985 | 54 +++++++++++++++++++++++++++++++++++++++
tests/data/test986 | 53 ++++++++++++++++++++++++++++++++++++++
7 files changed, 195 insertions(+), 36 deletions(-)
create mode 100644 tests/data/test984
create mode 100644 tests/data/test985
create mode 100644 tests/data/test986
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -2642,9 +2642,12 @@ static CURLcode ftp_statemach_act(struct
/* we have now received a full FTP server response */
switch(ftpc->state) {
case FTP_WAIT220:
- if(ftpcode == 230)
- /* 230 User logged in - already! */
- return ftp_state_user_resp(conn, ftpcode, ftpc->state);
+ if(ftpcode == 230) {
+ /* 230 User logged in - already! Take as 220 if TLS required. */
+ if(data->set.use_ssl <= CURLUSESSL_TRY ||
+ conn->bits.ftp_use_control_ssl)
+ return ftp_state_user_resp(conn, ftpcode, ftpc->state);
+ }
else if(ftpcode != 220) {
failf(data, "Got a %03d ftp-server response when 220 was expected",
ftpcode);
--- a/lib/imap.c
+++ b/lib/imap.c
@@ -919,22 +919,18 @@ static CURLcode imap_state_capability_re
line += wordlen;
}
}
- else if(imapcode == IMAP_RESP_OK) {
- if(data->set.use_ssl && !conn->ssl[FIRSTSOCKET].use) {
- /* We don't have a SSL/TLS connection yet, but SSL is requested */
- if(imapc->tls_supported)
- /* Switch to TLS connection now */
- result = imap_perform_starttls(conn);
- else if(data->set.use_ssl == CURLUSESSL_TRY)
- /* Fallback and carry on with authentication */
- result = imap_perform_authentication(conn);
- else {
- failf(data, "STARTTLS not supported.");
- result = CURLE_USE_SSL_FAILED;
- }
+ else if(data->set.use_ssl && !conn->ssl[FIRSTSOCKET].use) {
+ /* PREAUTH is not compatible with STARTTLS. */
+ if(imapcode == IMAP_RESP_OK && imapc->tls_supported && !imapc->preauth) {
+ /* Switch to TLS connection now */
+ result = imap_perform_starttls(conn);
}
- else
+ else if(data->set.use_ssl <= CURLUSESSL_TRY)
result = imap_perform_authentication(conn);
+ else {
+ failf(data, "STARTTLS not available.");
+ result = CURLE_USE_SSL_FAILED;
+ }
}
else
result = imap_perform_authentication(conn);
--- a/lib/pop3.c
+++ b/lib/pop3.c
@@ -723,28 +723,23 @@ static CURLcode pop3_state_capa_resp(str
}
}
}
- else if(pop3code == '+') {
- if(data->set.use_ssl && !conn->ssl[FIRSTSOCKET].use) {
- /* We don't have a SSL/TLS connection yet, but SSL is requested */
- if(pop3c->tls_supported)
- /* Switch to TLS connection now */
- result = pop3_perform_starttls(conn);
- else if(data->set.use_ssl == CURLUSESSL_TRY)
- /* Fallback and carry on with authentication */
- result = pop3_perform_authentication(conn);
- else {
- failf(data, "STLS not supported.");
- result = CURLE_USE_SSL_FAILED;
- }
- }
- else
- result = pop3_perform_authentication(conn);
- }
else {
/* Clear text is supported when CAPA isn't recognised */
- pop3c->authtypes |= POP3_TYPE_CLEARTEXT;
+ if(pop3code != '+')
+ pop3c->authtypes |= POP3_TYPE_CLEARTEXT;
- result = pop3_perform_authentication(conn);
+ if(!data->set.use_ssl || conn->ssl[FIRSTSOCKET].use)
+ result = pop3_perform_authentication(conn);
+ else if(pop3code == '+' && pop3c->tls_supported)
+ /* Switch to TLS connection now */
+ result = pop3_perform_starttls(conn);
+ else if(data->set.use_ssl <= CURLUSESSL_TRY)
+ /* Fallback and carry on with authentication */
+ result = pop3_perform_authentication(conn);
+ else {
+ failf(data, "STLS not supported.");
+ result = CURLE_USE_SSL_FAILED;
+ }
}
return result;
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -115,6 +115,8 @@ test945 test946 test947 test948 test949
test954 test955 test956 test957 test958 test959 test960 test961 test962 \
test963 test964 test965 test966 test967 test968 test969 test970 test971 \
\
+test984 test985 test986 \
+\
test1000 test1001 test1002 test1003 test1004 test1005 test1006 test1007 \
test1008 test1009 test1010 test1011 test1012 test1013 test1014 test1015 \
test1016 test1017 test1018 test1019 test1020 test1021 test1022 test1023 \
--- /dev/null
+++ b/tests/data/test984
@@ -0,0 +1,56 @@
+<testcase>
+<info>
+<keywords>
+IMAP
+STARTTLS
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<servercmd>
+REPLY CAPABILITY A001 BAD Not implemented
+</servercmd>
+</reply>
+
+#
+# Client-side
+<client>
+<features>
+SSL
+</features>
+<server>
+imap
+</server>
+ <name>
+IMAP require STARTTLS with failing capabilities
+ </name>
+ <command>
+imap://%HOSTIP:%IMAPPORT/%TESTNUMBER -T log/upload%TESTNUMBER -u user:secret --ssl-reqd
+</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>
+# 64 is CURLE_USE_SSL_FAILED
+<errorcode>
+64
+</errorcode>
+<protocol>
+A001 CAPABILITY
+</protocol>
+</verify>
+</testcase>
--- /dev/null
+++ b/tests/data/test985
@@ -0,0 +1,54 @@
+<testcase>
+<info>
+<keywords>
+POP3
+STARTTLS
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<servercmd>
+REPLY CAPA -ERR Not implemented
+</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 require STARTTLS with failing capabilities
+ </name>
+ <command>
+pop3://%HOSTIP:%POP3PORT/%TESTNUMBER -u user:secret --ssl-reqd
+ </command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+# 64 is CURLE_USE_SSL_FAILED
+<errorcode>
+64
+</errorcode>
+<protocol>
+CAPA
+</protocol>
+</verify>
+</testcase>
--- /dev/null
+++ b/tests/data/test986
@@ -0,0 +1,53 @@
+<testcase>
+<info>
+<keywords>
+FTP
+STARTTLS
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<servercmd>
+REPLY welcome 230 Welcome
+REPLY AUTH 500 unknown command
+</servercmd>
+</reply>
+
+# Client-side
+<client>
+<features>
+SSL
+</features>
+<server>
+ftp
+</server>
+ <name>
+FTP require STARTTLS while preauthenticated
+ </name>
+<file name="log/test%TESTNUMBER.txt">
+data
+ to
+ see
+that FTPS
+works
+ so does it?
+</file>
+ <command>
+--ssl-reqd --ftp-ssl-control ftp://%HOSTIP:%FTPPORT/%TESTNUMBER -T log/test%TESTNUMBER.txt -u user:secret
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+# 64 is CURLE_USE_SSL_FAILED
+<errorcode>
+64
+</errorcode>
+<protocol>
+AUTH SSL
+AUTH TLS
+</protocol>
+</verify>
+</testcase>
