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//------------------------------------------------------------------------------
// <copyright file="HttpCapabilitiesSectionHandler.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.Configuration {
using System.Collections;
using System.Configuration;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Security;
using System.Security.Permissions;
using System.Text.RegularExpressions;
using System.Web.Configuration;
using System.Web.Util;
using System.Xml;
using Pair = System.Web.UI.Pair;
//
// ConfigureCapabilities is used to configure the CapabilitiesEvaluator object
//
public class HttpCapabilitiesSectionHandler : IConfigurationSectionHandler {
private const int _defaultUserAgentCacheKeyLength = 64;
public HttpCapabilitiesSectionHandler() {
}
class ParseState {
internal string SectionName;
internal HttpCapabilitiesDefaultProvider Evaluator;
internal ArrayList RuleList = new ArrayList();
internal ArrayList FileList = new ArrayList();
internal bool IsExternalFile = false;
internal ParseState() {}
}
//
// As required by IConfigurationSectionHandler
//
public object Create(object parent, object configurationContext, XmlNode section) {
// if called through client config don't even load HttpRuntime
if (!HandlerBase.IsServerConfiguration(configurationContext)) {
return null;
}
ParseState parseState = new ParseState();
parseState.SectionName = section.Name;
// the rule is going to be the previous rule followed by a list containing the new rules
parseState.Evaluator = new HttpCapabilitiesDefaultProvider((HttpCapabilitiesDefaultProvider)parent);
int userAgentCacheKeyLength = 0;
// Get the useragent string cachekey length
if (parent != null) {
userAgentCacheKeyLength = ((HttpCapabilitiesDefaultProvider)parent).UserAgentCacheKeyLength;
}
HandlerBase.GetAndRemovePositiveIntegerAttribute(section, "userAgentCacheKeyLength", ref userAgentCacheKeyLength);
if (userAgentCacheKeyLength == 0) {
userAgentCacheKeyLength = _defaultUserAgentCacheKeyLength;
}
parseState.Evaluator.UserAgentCacheKeyLength = userAgentCacheKeyLength;
string browserCapabilitiesProviderType = null;
if (parent != null) {
browserCapabilitiesProviderType = ((HttpCapabilitiesDefaultProvider)parent).BrowserCapabilitiesProviderType;
}
HandlerBase.GetAndRemoveNonEmptyStringAttribute(section, "provider", ref browserCapabilitiesProviderType);
parseState.Evaluator.BrowserCapabilitiesProviderType = browserCapabilitiesProviderType;
// check for random attributes
HandlerBase.CheckForUnrecognizedAttributes(section);
// iterate through XML section in order and apply the directives
ArrayList sublist;
sublist = RuleListFromElement(parseState, section, true);
if (sublist.Count > 0) {
parseState.RuleList.Add(new CapabilitiesSection(CapabilitiesRule.Filter, null, null, sublist));
}
if (parseState.FileList.Count > 0) {
parseState.IsExternalFile = true;
ResolveFiles(parseState, configurationContext);
}
// Add the new rules
parseState.Evaluator.AddRuleList(parseState.RuleList);
return parseState.Evaluator;
}
//
// Create a rule from an element
//
static CapabilitiesRule RuleFromElement(ParseState parseState, XmlNode element) {
int ruletype;
DelayedRegex regex;
CapabilitiesPattern pat;
// grab tag name
if (element.Name == "filter") {
ruletype = CapabilitiesRule.Filter;
}
else if (element.Name=="case") {
ruletype = CapabilitiesRule.Case;
}
else if (element.Name == "use") {
HandlerBase.CheckForNonCommentChildNodes(element);
string var = HandlerBase.RemoveRequiredAttribute(element, "var");
string strAs = HandlerBase.RemoveAttribute(element, "as");
HandlerBase.CheckForUnrecognizedAttributes(element);
if (strAs == null)
strAs = String.Empty;
parseState.Evaluator.AddDependency(var);
return new CapabilitiesUse(var, strAs);
}
else {
throw new ConfigurationErrorsException(
SR.GetString(SR.Unknown_tag_in_caps_config, element.Name),
element);
}
// grab attributes
String matchpat = HandlerBase.RemoveAttribute(element, "match");
String testpat = HandlerBase.RemoveAttribute(element, "with");
HandlerBase.CheckForUnrecognizedAttributes(element);
if (matchpat == null) {
if (testpat != null)
throw new ConfigurationErrorsException(SR.GetString(SR.Cannot_specify_test_without_match), element);
regex = null;
pat = null;
}
else {
try {
regex = new DelayedRegex(matchpat);
}
catch (Exception e) {
throw new ConfigurationErrorsException(e.Message, e, element);
}
if (testpat == null)
pat = CapabilitiesPattern.Default;
else
pat = new CapabilitiesPattern(testpat);
}
// grab contents
ArrayList subrules = RuleListFromElement(parseState, element, false);
return new CapabilitiesSection(ruletype, regex, pat, subrules);
}
//
// Create a rulelist from an element's children
//
static ArrayList RuleListFromElement(ParseState parseState, XmlNode node, bool top) {
ArrayList result = new ArrayList();
foreach (XmlNode child in node.ChildNodes) {
switch (child.NodeType) {
case XmlNodeType.Text:
case XmlNodeType.CDATA:
top = false;
AppendLines(result, child.Value, node);
break;
case XmlNodeType.Element:
switch (child.Name) {
case "result":
if (top) {
ProcessResult(parseState.Evaluator, child);
}
else {
throw new ConfigurationErrorsException(
SR.GetString(SR.Result_must_be_at_the_top_browser_section),
child);
}
break;
case "file":
if (parseState.IsExternalFile) {
throw new ConfigurationErrorsException(
SR.GetString(SR.File_element_only_valid_in_config),
child);
}
ProcessFile(parseState.FileList, child);
break;
default:
result.Add(RuleFromElement(parseState, child));
break;
}
top = false;
break;
case XmlNodeType.Comment:
case XmlNodeType.Whitespace:
break;
default:
HandlerBase.ThrowUnrecognizedElement(child);
break;
}
}
return result;
}
//
// Handle <file src=""/> elements
//
static void ProcessFile(ArrayList fileList, XmlNode node) {
string filename = null;
XmlNode attr = HandlerBase.GetAndRemoveRequiredStringAttribute(node, "src", ref filename);
HandlerBase.CheckForUnrecognizedAttributes(node);
HandlerBase.CheckForNonCommentChildNodes(node);
fileList.Add(new Pair(filename, attr));
}
//
// Handle the <result> tag
//
static void ProcessResult(HttpCapabilitiesDefaultProvider capabilitiesEvaluator, XmlNode node) {
bool inherit = true;
HandlerBase.GetAndRemoveBooleanAttribute(node, "inherit", ref inherit);
if (inherit == false) {
capabilitiesEvaluator.ClearParent();
}
Type resultType = null;
XmlNode attribute = HandlerBase.GetAndRemoveTypeAttribute(node, "type", ref resultType);
if (attribute != null) {
if (resultType.Equals(capabilitiesEvaluator._resultType) == false) {
// be sure the new type is assignable to the parent type
HandlerBase.CheckAssignableType(attribute, capabilitiesEvaluator._resultType, resultType);
capabilitiesEvaluator._resultType = resultType;
}
}
int cacheTime = 0;
attribute = HandlerBase.GetAndRemovePositiveIntegerAttribute(node, "cacheTime", ref cacheTime);
//NOTE: we continue to parse the cacheTime for backwards compat
// it has never been used. Customer scenarios don't require this support.
if (attribute != null) {
capabilitiesEvaluator.CacheTime = TimeSpan.FromSeconds(cacheTime);
}
HandlerBase.CheckForUnrecognizedAttributes(node);
HandlerBase.CheckForNonCommentChildNodes(node);
}
//
// ResolveFiles - parse files referenced with <file src="" />
//
[SuppressMessage("Microsoft.Security.Xml", "CA3056:UseXmlReaderForLoad", Justification = "Developer-controlled .xml files in application directory are implicitly trusted by ASP.Net.")]
static void ResolveFiles(ParseState parseState, object configurationContext) {
//
// 1) get the directory of the configuration file currently being parsed
//
HttpConfigurationContext httpConfigurationContext = (HttpConfigurationContext) configurationContext;
string configurationDirectory = null;
bool useAssert = false;
//
// Only assert to read cap files when parsing machine.config
// (allow device updates to work in restricted trust levels).
//
// Machine.config can be securely identified by the context being
// an HttpConfigurationContext with null path.
//
try {
if (httpConfigurationContext.VirtualPath == null) {
useAssert = true;
// we need to assert here to get the file path from ConfigurationException
FileIOPermission fiop = new FileIOPermission(PermissionState.None);
fiop.AllFiles = FileIOPermissionAccess.PathDiscovery;
fiop.Assert();
}
Pair pair0 = (Pair)parseState.FileList[0];
XmlNode srcAttribute = (XmlNode)pair0.Second;
configurationDirectory = Path.GetDirectoryName(ConfigurationErrorsException.GetFilename(srcAttribute));
}
finally {
if (useAssert) {
CodeAccessPermission.RevertAssert();
}
}
//
// 2) iterate through list of referenced files, builing rule lists for each
//
foreach (Pair pair in parseState.FileList) {
string srcFilename = (string)pair.First;
string fullFilename = Path.Combine(configurationDirectory, srcFilename);
XmlNode section;
try {
if (useAssert) {
InternalSecurityPermissions.FileReadAccess(fullFilename).Assert();
}
Exception fcmException = null;
try {
HttpConfigurationSystem.AddFileDependency(fullFilename);
}
catch (Exception e) {
fcmException = e;
}
ConfigXmlDocument configDoc = new ConfigXmlDocument();
try {
configDoc.Load(fullFilename);
section = configDoc.DocumentElement;
}
catch (Exception e) {
throw new ConfigurationErrorsException(SR.GetString(SR.Error_loading_XML_file, fullFilename, e.Message),
e, (XmlNode)pair.Second);
}
if (fcmException != null) {
throw fcmException;
}
}
finally {
if (useAssert) {
// Cannot apply next FileReadAccess PermissionSet unless
// current set is explicitly reverted. Also minimizes
// granted permissions.
CodeAccessPermission.RevertAssert();
}
}
if (section.Name != parseState.SectionName) {
throw new ConfigurationErrorsException(SR.GetString(SR.Capability_file_root_element, parseState.SectionName),
section);
}
HandlerBase.CheckForUnrecognizedAttributes(section);
ArrayList sublist = RuleListFromElement(parseState, section, true);
if (sublist.Count > 0) {
parseState.RuleList.Add(new CapabilitiesSection(CapabilitiesRule.Filter, null, null, sublist));
}
}
}
//
// Regex dealing with a=b lines
//
static Regex lineRegex = new Regex
(
"\\G" + // anchored
"(?<var>\\w+)" + // variable name
"\\s*=\\s*" + // equals sign
"(?:" +
"\"(?<pat>[^\"\r\n\\\\]*" + // quoted pattern
"(?:\\\\.[^\"\r\n\\\\]*)*)\"" +
"|(?!\")(?<pat>\\S+)" + // unquoted pattern
")" +
"\\s*" // trailing whitespace
);
static Regex wsRegex = new Regex("\\G\\s*");
static Regex errRegex = new Regex("\\G\\S {0,8}");
static void AppendLines(ArrayList setlist, String text, XmlNode node) {
int lineNumber = ConfigurationErrorsException.GetLineNumber(node);
int textpos;
textpos = 0;
for (;;) {
Match match;
if ((match = wsRegex.Match(text, textpos)).Success) {
lineNumber += System.Web.UI.Util.LineCount(text, textpos, match.Index + match.Length);
textpos = match.Index + match.Length;
}
if (textpos == text.Length)
break;
if ((match = lineRegex.Match(text, textpos)).Success) {
setlist.Add(new CapabilitiesAssignment(match.Groups["var"].Value,
new CapabilitiesPattern(match.Groups["pat"].Value)));
lineNumber += System.Web.UI.Util.LineCount(text, textpos, match.Index + match.Length);
textpos = match.Index + match.Length;
}
else {
match = errRegex.Match(text, textpos);
throw new ConfigurationErrorsException(
SR.GetString(SR.Problem_reading_caps_config, match.ToString()),
ConfigurationErrorsException.GetFilename(node),
lineNumber);
}
}
}
}
}
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