[Pkg-voip-commits] [asterisk] 02/02: AST-2015-002 CURL() HTTP request injection issues

tzafrir at debian.org tzafrir at debian.org
Fri Jan 30 10:13:56 UTC 2015


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tzafrir pushed a commit to branch jessie
in repository asterisk.

commit 467993f3f4a36c5a6be6559650cbc8a85b70a8b0
Author: Tzafrir Cohen <tzafrir at debian.org>
Date:   Fri Jan 30 00:20:43 2015 +0200

    AST-2015-002 CURL() HTTP request injection issues
    
    Adds AST-2015-002.patch to fix various HTTP injection issues in the CURL
    function.
---
 debian/patches/AST-2015-002.patch | 156 ++++++++++++++++++++++++++++++++++++++
 debian/patches/series             |   1 +
 2 files changed, 157 insertions(+)

diff --git a/debian/patches/AST-2015-002.patch b/debian/patches/AST-2015-002.patch
new file mode 100644
index 0000000..02bc9c6
--- /dev/null
+++ b/debian/patches/AST-2015-002.patch
@@ -0,0 +1,156 @@
+From 39bd4ff0a20297ad0632a675ba414d6aaf4a35cd Mon Sep 17 00:00:00 2001
+From: Mark Michelson <mmichelson at digium.com>
+Date: Wed, 28 Jan 2015 17:05:26 +0000
+Subject: Mitigate possible HTTP injection attacks using CURL() function in Asterisk.
+Bug: https://issues.asterisk.org/jira/browse/ASTERISK-24676
+Origin: http://svnview.digium.com/svn/asterisk?view=rev&rev=431297
+
+CVE-2014-8150 disclosed a vulnerability in libcURL where HTTP request injection
+can be performed given properly-crafted URLs.
+
+Since Asterisk makes use of libcURL, and it is possible that users of Asterisk may
+get cURL URLs from user input or remote sources, we have made a patch to Asterisk
+to prevent such HTTP injection attacks from originating from Asterisk.
+
+Review: https://reviewboard.asterisk.org/r/4364
+
+See also http://downloads.asterisk.org/pub/security/AST-2015-002.html
+
+Includes the compilation fix from the following commit r431298.
+
+---
+ funcs/func_curl.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 83 insertions(+)
+
+diff --git a/funcs/func_curl.c b/funcs/func_curl.c
+index 1a69071..480e677 100644
+--- a/funcs/func_curl.c
++++ b/funcs/func_curl.c
+@@ -50,6 +50,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+ #include "asterisk/app.h"
+ #include "asterisk/utils.h"
+ #include "asterisk/threadstorage.h"
++#include "asterisk/test.h"
+ 
+ /*** DOCUMENTATION
+ 	<function name="CURL" language="en_US">
+@@ -568,6 +569,31 @@ static void curl_instance_cleanup(void *data)
+ AST_THREADSTORAGE_CUSTOM(curl_instance, curl_instance_init, curl_instance_cleanup);
+ AST_THREADSTORAGE(thread_escapebuf);
+ 
++/*!
++ * \brief Check for potential HTTP injection risk.
++ *
++ * CVE-2014-8150 brought up the fact that HTTP proxies are subject to injection
++ * attacks. An HTTP URL sent to a proxy contains a carriage-return linefeed combination,
++ * followed by a complete HTTP request. Proxies will handle this as two separate HTTP
++ * requests rather than as a malformed URL.
++ *
++ * libcURL patched this vulnerability in version 7.40.0, but we have no guarantee that
++ * Asterisk systems will be using an up-to-date cURL library. Therefore, we implement
++ * the same fix as libcURL for determining if a URL is vulnerable to an injection attack.
++ *
++ * \param url The URL to check for vulnerability
++ * \retval 0 The URL is not vulnerable
++ * \retval 1 The URL is vulnerable.
++ */
++static int url_is_vulnerable(const char *url)
++{
++	if (strpbrk(url, "\r\n")) {
++		return 1;
++	}
++
++	return 0;
++}
++
+ static int acf_curl_helper(struct ast_channel *chan, const char *cmd, char *info, char *buf, struct ast_str **input_str, ssize_t len)
+ {
+ 	struct ast_str *escapebuf = ast_str_thread_get(&thread_escapebuf, 16);
+@@ -605,6 +631,11 @@ static int acf_curl_helper(struct ast_channel *chan, const char *cmd, char *info
+ 
+ 	AST_STANDARD_APP_ARGS(args, info);
+ 
++	if (url_is_vulnerable(args.url)) {
++		ast_log(LOG_ERROR, "URL '%s' is vulnerable to HTTP injection attacks. Aborting CURL() call.\n", args.url);
++		return -1;
++	}
++
+ 	if (chan) {
+ 		ast_autoservice_start(chan);
+ 	}
+@@ -763,6 +794,54 @@ static struct ast_custom_function acf_curlopt = {
+ 	.write = acf_curlopt_write,
+ };
+ 
++AST_TEST_DEFINE(vulnerable_url)
++{
++	const char *bad_urls [] = {
++		"http://example.com\r\nDELETE http://example.com/everything",
++		"http://example.com\rDELETE http://example.com/everything",
++		"http://example.com\nDELETE http://example.com/everything",
++		"\r\nhttp://example.com",
++		"\rhttp://example.com",
++		"\nhttp://example.com",
++		"http://example.com\r\n",
++		"http://example.com\r",
++		"http://example.com\n",
++	};
++	const char *good_urls [] = {
++		"http://example.com",
++		"http://example.com/%5Cr%5Cn",
++	};
++	int i;
++	enum ast_test_result_state res = AST_TEST_PASS;
++
++	switch (cmd) {
++	case TEST_INIT:
++		info->name = "vulnerable_url";
++		info->category = "/funcs/func_curl/";
++		info->summary = "cURL vulnerable URL test";
++		info->description =
++			"Ensure that any combination of '\\r' or '\\n' in a URL invalidates the URL";
++	case TEST_EXECUTE:
++		break;
++	}
++
++	for (i = 0; i < ARRAY_LEN(bad_urls); ++i) {
++		if (!url_is_vulnerable(bad_urls[i])) {
++			ast_test_status_update(test, "String '%s' detected as valid when it should be invalid\n", bad_urls[i]);
++			res = AST_TEST_FAIL;
++		}
++	}
++
++	for (i = 0; i < ARRAY_LEN(good_urls); ++i) {
++		if (url_is_vulnerable(good_urls[i])) {
++			ast_test_status_update(test, "String '%s' detected as invalid when it should be valid\n", good_urls[i]);
++			res = AST_TEST_FAIL;
++		}
++	}
++
++	return res;
++}
++
+ static int unload_module(void)
+ {
+ 	int res;
+@@ -770,6 +849,8 @@ static int unload_module(void)
+ 	res = ast_custom_function_unregister(&acf_curl);
+ 	res |= ast_custom_function_unregister(&acf_curlopt);
+ 
++	AST_TEST_UNREGISTER(vulnerable_url);
++
+ 	return res;
+ }
+ 
+@@ -787,6 +868,8 @@ static int load_module(void)
+ 	res = ast_custom_function_register(&acf_curl);
+ 	res |= ast_custom_function_register(&acf_curlopt);
+ 
++	AST_TEST_REGISTER(vulnerable_url);
++
+ 	return res;
+ }
+ 
+-- 
+2.1.4
+
diff --git a/debian/patches/series b/debian/patches/series
index ef501eb..6802868 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -39,3 +39,4 @@ AST-2014-014.patch
 AST-2014-017.patch
 AST-2014-018.patch
 AST-2014-019.patch
+AST-2015-002.patch

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