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authorJohn Hurliman2010-03-03 14:38:00 -0800
committerJohn Hurliman2010-03-03 14:38:00 -0800
commit61a63ff85124d932cca5a2aeba9ae685fa7f146f (patch)
treeae5337063e486e32131a188c3d6b50b4695b1f09 /OpenSim/Framework/UntrustedWebRequest.cs
parent* Adjusted the significant movement magic value from 0.5m to 2.0m and added a... (diff)
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* Added three new helper utility files to OpenSim.Framework. MultipartForm is used for constructing multipart/form-data requests. UntrustedWebRequest places sanity checks and policy on requests to HTTP endpoints that are not in the same trust domain (useful for Hypergrid, OpenID, etc). WebUtil contains misc. functions for managing URLs and network streams
Diffstat (limited to 'OpenSim/Framework/UntrustedWebRequest.cs')
-rw-r--r--OpenSim/Framework/UntrustedWebRequest.cs203
1 files changed, 203 insertions, 0 deletions
diff --git a/OpenSim/Framework/UntrustedWebRequest.cs b/OpenSim/Framework/UntrustedWebRequest.cs
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1using System;
2using System.Collections.Generic;
3using System.IO;
4using System.Net;
5using System.Net.Security;
6using System.Text;
7using log4net;
8
9namespace OpenSim.Framework
10{
11 /// <summary>
12 /// Used for requests to untrusted endpoints that may potentially be
13 /// malicious
14 /// </summary>
15 public static class UntrustedHttpWebRequest
16 {
17 /// <summary>Setting this to true will allow HTTP connections to localhost</summary>
18 private const bool DEBUG = true;
19
20 private static readonly ILog m_log =
21 LogManager.GetLogger(
22 System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
23
24 private static readonly ICollection<string> allowableSchemes = new List<string> { "http", "https" };
25
26 /// <summary>
27 /// Creates an HttpWebRequest that is hardened against malicious
28 /// endpoints after ensuring the given Uri is safe to retrieve
29 /// </summary>
30 /// <param name="uri">Web location to request</param>
31 /// <returns>A hardened HttpWebRequest if the uri was determined to be safe</returns>
32 /// <exception cref="ArgumentNullException">If uri is null</exception>
33 /// <exception cref="ArgumentException">If uri is unsafe</exception>
34 public static HttpWebRequest Create(Uri uri)
35 {
36 return Create(uri, DEBUG, 1000 * 5, 1000 * 20, 10);
37 }
38
39 /// <summary>
40 /// Creates an HttpWebRequest that is hardened against malicious
41 /// endpoints after ensuring the given Uri is safe to retrieve
42 /// </summary>
43 /// <param name="uri">Web location to request</param>
44 /// <param name="allowLoopback">True to allow connections to localhost, otherwise false</param>
45 /// <param name="readWriteTimeoutMS">Read write timeout, in milliseconds</param>
46 /// <param name="timeoutMS">Connection timeout, in milliseconds</param>
47 /// <param name="maximumRedirects">Maximum number of allowed redirects</param>
48 /// <returns>A hardened HttpWebRequest if the uri was determined to be safe</returns>
49 /// <exception cref="ArgumentNullException">If uri is null</exception>
50 /// <exception cref="ArgumentException">If uri is unsafe</exception>
51 public static HttpWebRequest Create(Uri uri, bool allowLoopback, int readWriteTimeoutMS, int timeoutMS, int maximumRedirects)
52 {
53 if (uri == null)
54 throw new ArgumentNullException("uri");
55
56 if (!IsUriAllowable(uri, allowLoopback))
57 throw new ArgumentException("Uri " + uri + " was rejected");
58
59 HttpWebRequest httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(uri);
60 httpWebRequest.MaximumAutomaticRedirections = maximumRedirects;
61 httpWebRequest.ReadWriteTimeout = readWriteTimeoutMS;
62 httpWebRequest.Timeout = timeoutMS;
63 httpWebRequest.KeepAlive = false;
64
65 return httpWebRequest;
66 }
67
68 public static string PostToUntrustedUrl(Uri url, string data)
69 {
70 try
71 {
72 byte[] requestData = System.Text.Encoding.UTF8.GetBytes(data);
73
74 HttpWebRequest request = Create(url);
75 request.Method = "POST";
76 request.ContentLength = requestData.Length;
77 request.ContentType = "application/x-www-form-urlencoded";
78
79 using (Stream requestStream = request.GetRequestStream())
80 requestStream.Write(requestData, 0, requestData.Length);
81
82 using (WebResponse response = request.GetResponse())
83 {
84 using (Stream responseStream = response.GetResponseStream())
85 return responseStream.GetStreamString();
86 }
87 }
88 catch (Exception ex)
89 {
90 m_log.Warn("POST to untrusted URL " + url + " failed: " + ex.Message);
91 return null;
92 }
93 }
94
95 public static string GetUntrustedUrl(Uri url)
96 {
97 try
98 {
99 HttpWebRequest request = Create(url);
100
101 using (WebResponse response = request.GetResponse())
102 {
103 using (Stream responseStream = response.GetResponseStream())
104 return responseStream.GetStreamString();
105 }
106 }
107 catch (Exception ex)
108 {
109 m_log.Warn("GET from untrusted URL " + url + " failed: " + ex.Message);
110 return null;
111 }
112 }
113
114 /// <summary>
115 /// Determines whether a URI is allowed based on scheme and host name.
116 /// No requireSSL check is done here
117 /// </summary>
118 /// <param name="allowLoopback">True to allow loopback addresses to be used</param>
119 /// <param name="uri">The URI to test for whether it should be allowed.</param>
120 /// <returns>
121 /// <c>true</c> if [is URI allowable] [the specified URI]; otherwise, <c>false</c>.
122 /// </returns>
123 private static bool IsUriAllowable(Uri uri, bool allowLoopback)
124 {
125 if (!allowableSchemes.Contains(uri.Scheme))
126 {
127 m_log.WarnFormat("Rejecting URL {0} because it uses a disallowed scheme.", uri);
128 return false;
129 }
130
131 // Try to interpret the hostname as an IP address so we can test for internal
132 // IP address ranges. Note that IP addresses can appear in many forms
133 // (e.g. http://127.0.0.1, http://2130706433, http://0x0100007f, http://::1
134 // So we convert them to a canonical IPAddress instance, and test for all
135 // non-routable IP ranges: 10.*.*.*, 127.*.*.*, ::1
136 // Note that Uri.IsLoopback is very unreliable, not catching many of these variants.
137 IPAddress hostIPAddress;
138 if (IPAddress.TryParse(uri.DnsSafeHost, out hostIPAddress))
139 {
140 byte[] addressBytes = hostIPAddress.GetAddressBytes();
141
142 // The host is actually an IP address.
143 switch (hostIPAddress.AddressFamily)
144 {
145 case System.Net.Sockets.AddressFamily.InterNetwork:
146 if (!allowLoopback && (addressBytes[0] == 127 || addressBytes[0] == 10))
147 {
148 m_log.WarnFormat("Rejecting URL {0} because it is a loopback address.", uri);
149 return false;
150 }
151 break;
152 case System.Net.Sockets.AddressFamily.InterNetworkV6:
153 if (!allowLoopback && IsIPv6Loopback(hostIPAddress))
154 {
155 m_log.WarnFormat("Rejecting URL {0} because it is a loopback address.", uri);
156 return false;
157 }
158 break;
159 default:
160 m_log.WarnFormat("Rejecting URL {0} because it does not use an IPv4 or IPv6 address.", uri);
161 return false;
162 }
163 }
164 else
165 {
166 // The host is given by name. We require names to contain periods to
167 // help make sure it's not an internal address.
168 if (!allowLoopback && !uri.Host.Contains("."))
169 {
170 m_log.WarnFormat("Rejecting URL {0} because it does not contain a period in the host name.", uri);
171 return false;
172 }
173 }
174
175 return true;
176 }
177
178 /// <summary>
179 /// Determines whether an IP address is the IPv6 equivalent of "localhost/127.0.0.1".
180 /// </summary>
181 /// <param name="ip">The ip address to check.</param>
182 /// <returns>
183 /// <c>true</c> if this is a loopback IP address; <c>false</c> otherwise.
184 /// </returns>
185 private static bool IsIPv6Loopback(IPAddress ip)
186 {
187 if (ip == null)
188 throw new ArgumentNullException("ip");
189
190 byte[] addressBytes = ip.GetAddressBytes();
191 for (int i = 0; i < addressBytes.Length - 1; i++)
192 {
193 if (addressBytes[i] != 0)
194 return false;
195 }
196
197 if (addressBytes[addressBytes.Length - 1] != 1)
198 return false;
199
200 return true;
201 }
202 }
203}