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137 lines
4.4 KiB
137 lines
4.4 KiB
From 1d66562c67fc0099d0fd882c693e51dd0b10c45c Mon Sep 17 00:00:00 2001
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From: Jay Satiro <raysatiro@yahoo.com>
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Date: Sat, 30 Sep 2023 03:40:02 -0400
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Subject: [PATCH] socks: return error if hostname too long for remote resolve
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Prior to this change the state machine attempted to change the remote
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resolve to a local resolve if the hostname was longer than 255
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characters. Unfortunately that did not work as intended and caused a
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security issue.
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Name resolvers cannot resolve hostnames longer than 255 characters.
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Bug: https://curl.se/docs/CVE-2023-38545.html
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---
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lib/socks.c | 8 +++---
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tests/data/Makefile.inc | 2 +-
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tests/data/test728 | 64 +++++++++++++++++++++++++++++++++++++++++
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3 files changed, 69 insertions(+), 5 deletions(-)
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create mode 100644 tests/data/test728
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diff --git a/lib/socks.c b/lib/socks.c
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index c492d663c..a7b5ab07e 100644
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--- a/lib/socks.c
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+++ b/lib/socks.c
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@@ -531,13 +531,13 @@ CURLproxycode Curl_SOCKS5(const char *proxy_user,
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infof(data, "SOCKS5: connecting to HTTP proxy %s port %d\n",
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hostname, remote_port);
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/* RFC1928 chapter 5 specifies max 255 chars for domain name in packet */
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if(!socks5_resolve_local && hostname_len > 255) {
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- infof(data, "SOCKS5: server resolving disabled for hostnames of "
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- "length > 255 [actual len=%zu]\n", hostname_len);
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- socks5_resolve_local = TRUE;
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+ failf(data, "SOCKS5: the destination hostname is too long to be "
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+ "resolved remotely by the proxy.");
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+ return CURLPX_LONG_HOSTNAME;
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}
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if(auth & ~(CURLAUTH_BASIC | CURLAUTH_GSSAPI))
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infof(data,
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"warning: unsupported value passed to CURLOPT_SOCKS5_AUTH: %lu\n",
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@@ -855,7 +855,7 @@ CONNECT_RESOLVE_REMOTE:
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if(!socks5_resolve_local) {
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socksreq[len++] = 3; /* ATYP: domain name = 3 */
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- socksreq[len++] = (char) hostname_len; /* one byte address length */
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+ socksreq[len++] = (unsigned char) hostname_len; /* one byte length */
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memcpy(&socksreq[len], hostname, hostname_len); /* address w/o NULL */
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len += hostname_len;
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infof(data, "SOCKS5 connect to %s:%d (remotely resolved)\n",
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diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
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index 081e344d4..62ee53578 100644
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--- a/tests/data/Makefile.inc
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+++ b/tests/data/Makefile.inc
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@@ -99,7 +99,7 @@ test672 test673 test674 test675 test676 test677 test678 test679 test680 \
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\
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test700 test701 test702 test703 test704 test705 test706 test707 test708 \
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test709 test710 test711 test712 test713 test714 test715 test716 test717 \
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-test718 \
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+test718 test728 \
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\
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test800 test801 test802 test803 test804 test805 test806 test807 test808 \
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test809 test810 test811 test812 test813 test814 test815 test816 test817 \
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diff --git a/tests/data/test728 b/tests/data/test728
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new file mode 100644
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index 000000000..05bcf2883
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--- /dev/null
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+++ b/tests/data/test728
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@@ -0,0 +1,64 @@
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+<testcase>
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+<info>
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+<keywords>
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+HTTP
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+HTTP GET
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+SOCKS5
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+SOCKS5h
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+followlocation
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+</keywords>
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+</info>
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+
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+#
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+# Server-side
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+<reply>
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+# The hostname in this redirect is 256 characters and too long (> 255) for
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+# SOCKS5 remote resolve. curl must return error CURLE_PROXY in this case.
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+<data>
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+HTTP/1.1 301 Moved Permanently
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+Location: http://AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA/
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+Content-Length: 0
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+Connection: close
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+
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+</data>
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+</reply>
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+
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+#
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+# Client-side
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+<client>
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+<features>
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+proxy
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+</features>
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+<server>
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+http
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+socks5
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+</server>
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+ <name>
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+SOCKS5h with HTTP redirect to hostname too long
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+ </name>
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+ <command>
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+--no-progress-meter --location --proxy socks5h://%HOSTIP:%SOCKSPORT http://%HOSTIP:%HTTPPORT/%TESTNUMBER
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+</command>
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+</client>
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+
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+#
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+# Verify data after the test has been "shot"
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+<verify>
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+<protocol crlf="yes">
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+GET /%TESTNUMBER HTTP/1.1
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+Host: %HOSTIP:%HTTPPORT
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+User-Agent: curl/%VERSION
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+Accept: */*
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+
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+</protocol>
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+<errorcode>
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+97
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+</errorcode>
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+# the error message is verified because error code CURLE_PROXY (97) may be
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+# returned for any number of reasons and we need to make sure it is
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+# specifically for the reason below so that we know the check is working.
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+<stderr mode="text">
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+curl: (97) SOCKS5: the destination hostname is too long to be resolved remotely by the proxy.
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+</stderr>
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+</verify>
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+</testcase>
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--
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2.42.0
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