File curl-CVE-2023-38545.patch of Package curl.30922
From a6c541e709096a09eb3df6a8fbbe058239d63a55 Mon Sep 17 00:00:00 2001
From: Jay Satiro <raysatiro@yahoo.com>
Date: Sat, 30 Sep 2023 03:40:02 -0400
Subject: [PATCH] socks: return error if hostname too long for remote resolve
Prior to this change the state machine attempted to change the remote
resolve to a local resolve if the hostname was too long. Unfortunately
that did not always work as intended, leading to a security issue. And
when it did it's a privacy violation for users of socks5h that may
expect their DNS requests will not leak.
Bug: https://curl.se/docs/CVE-2023-38545.html
---
lib/socks.c | 13 +++++----
tests/data/Makefile.inc | 2 +-
tests/data/test728 | 64 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 73 insertions(+), 6 deletions(-)
create mode 100644 tests/data/test728
Index: curl-8.0.1/lib/socks.c
===================================================================
--- curl-8.0.1.orig/lib/socks.c
+++ curl-8.0.1/lib/socks.c
@@ -586,11 +586,14 @@ static CURLproxycode do_SOCKS5(struct Cu
infof(data, "SOCKS5: connecting to HTTP proxy %s port %d",
sx->hostname, sx->remote_port);
- /* RFC1928 chapter 5 specifies max 255 chars for domain name in packet */
+ /* RFC1928 chapter 5 specifies max 255 chars for domain name in packet.
+ If remote resolve is enabled and the host is too long then error.
+ The user's resolve setting is not overridden because that could be a
+ privacy violation and unexpected. */
if(!socks5_resolve_local && hostname_len > 255) {
- infof(data, "SOCKS5: server resolving disabled for hostnames of "
- "length > 255 [actual len=%zu]", hostname_len);
- socks5_resolve_local = TRUE;
+ failf(data, "SOCKS5: the destination hostname is too long to be "
+ "resolved remotely by the proxy.");
+ return CURLPX_LONG_HOSTNAME;
}
if(auth & ~(CURLAUTH_BASIC | CURLAUTH_GSSAPI))
@@ -904,7 +907,7 @@ static CURLproxycode do_SOCKS5(struct Cu
}
else {
socksreq[len++] = 3;
- socksreq[len++] = (char) hostname_len; /* one byte address length */
+ socksreq[len++] = (unsigned char) hostname_len; /* one byte length */
memcpy(&socksreq[len], sx->hostname, hostname_len); /* w/o NULL */
len += hostname_len;
}
Index: curl-8.0.1/tests/data/Makefile.inc
===================================================================
--- curl-8.0.1.orig/tests/data/Makefile.inc
+++ curl-8.0.1/tests/data/Makefile.inc
@@ -101,6 +101,7 @@ test679 test680 test681 test682 test683
test700 test701 test702 test703 test704 test705 test706 test707 test708 \
test709 test710 test711 test712 test713 test714 test715 test716 test717 \
test718 test719 test720 test721 \
+test728 \
\
test800 test801 test802 test803 test804 test805 test806 test807 test808 \
test809 test810 test811 test812 test813 test814 test815 test816 test817 \
Index: curl-8.0.1/tests/data/test728
===================================================================
--- /dev/null
+++ curl-8.0.1/tests/data/test728
@@ -0,0 +1,64 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+SOCKS5
+SOCKS5h
+followlocation
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+# The hostname in this redirect is 256 characters and too long (> 255) for
+# SOCKS5 remote resolve. curl must return error CURLE_PROXY in this case.
+<data>
+HTTP/1.1 301 Moved Permanently
+Location: http://AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA/
+Content-Length: 0
+Connection: close
+
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<features>
+proxy
+</features>
+<server>
+http
+socks5
+</server>
+ <name>
+SOCKS5h with HTTP redirect to hostname too long
+ </name>
+ <command>
+--no-progress-meter --location --proxy socks5h://%HOSTIP:%SOCKSPORT http://%HOSTIP:%HTTPPORT/%TESTNUMBER
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes">
+GET /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+</protocol>
+<errorcode>
+97
+</errorcode>
+# the error message is verified because error code CURLE_PROXY (97) may be
+# returned for any number of reasons and we need to make sure it is
+# specifically for the reason below so that we know the check is working.
+<stderr mode="text">
+curl: (97) SOCKS5: the destination hostname is too long to be resolved remotely by the proxy.
+</stderr>
+</verify>
+</testcase>
