/// <summary>
/// Parse the DigestMethod tag
/// </summary>
/// <param name="reader"></param>
private static string ParseDigestAlgorithmTag(XmlReader reader)
{
// verify namespace and lack of attributes
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) > 1 ||
String.CompareOrdinal(reader.NamespaceURI, SignedXml.XmlDsigNamespaceUrl) != 0 ||
reader.Depth != 3)
{
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
// get the Algorithm attribute
string hashAlgorithm = null;
if (reader.HasAttributes)
{
hashAlgorithm = reader.GetAttribute(XTable.Get(XTable.ID.AlgorithmAttrName));
}
if (hashAlgorithm == null || hashAlgorithm.Length == 0)
{
throw new XmlException(SR.Get(SRID.UnsupportedHashAlgorithm));
}
return(hashAlgorithm);
}
/// <summary>
/// Parse the Relationship-specific Transform
/// </summary>
/// <param name="reader"></param>
/// <param name="partUri"></param>
/// <param name="relationshipSelectors">may be allocated but will never be empty</param>
private static void ParseRelationshipsTransform(XmlReader reader, Uri partUri, ref List <PackageRelationshipSelector> relationshipSelectors)
{
Uri owningPartUri = PackUriHelper.GetSourcePartUriFromRelationshipPartUri(partUri);
// find all of the Relationship tags of form:
// <RelationshipReference SourceId="abc123" />
// or
// <RelationshipsGroupReference SourceType="reference-type-of-the-week" />
while (reader.Read() && (reader.MoveToContent() == XmlNodeType.Element) &&
reader.Depth == 5)
{
// both types have no children, a single required attribute and belong to the OPC namespace
if (reader.IsEmptyElement &&
PackagingUtilities.GetNonXmlnsAttributeCount(reader) == 1 &&
(String.CompareOrdinal(reader.NamespaceURI, XTable.Get(XTable.ID.OpcSignatureNamespace)) == 0))
{
// <RelationshipReference>?
if (String.CompareOrdinal(reader.LocalName, XTable.Get(XTable.ID.RelationshipReferenceTagName)) == 0)
{
// RelationshipReference tags are legal and these must be empty with a single SourceId attribute
// get the SourceId attribute
string id = reader.GetAttribute(XTable.Get(XTable.ID.SourceIdAttrName));
if (id != null && id.Length > 0)
{
if (relationshipSelectors == null)
{
relationshipSelectors = new List <PackageRelationshipSelector>();
}
// we found a legal SourceId so create a selector and continue searching
relationshipSelectors.Add(new PackageRelationshipSelector(owningPartUri, PackageRelationshipSelectorType.Id, id));
continue;
}
} // <RelationshipsGroupReference>?
else if ((String.CompareOrdinal(reader.LocalName, XTable.Get(XTable.ID.RelationshipsGroupReferenceTagName)) == 0))
{
// RelationshipsGroupReference tags must be empty with a single SourceType attribute
string type = reader.GetAttribute(XTable.Get(XTable.ID.SourceTypeAttrName));
if (type != null && type.Length > 0)
{
// lazy init
if (relationshipSelectors == null)
{
relationshipSelectors = new List <PackageRelationshipSelector>();
}
// got a legal SourceType attribute
relationshipSelectors.Add(new PackageRelationshipSelector(owningPartUri, PackageRelationshipSelectorType.Type, type));
continue;
}
}
}
// if we get to here, we have not found a legal tag so we throw
throw new XmlException(SR.Get(SRID.UnexpectedXmlTag, reader.LocalName));
}
}
/// <summary>
/// Parse the DigestValue tag
/// </summary>
/// <param name="reader"></param>
private static string ParseDigestValueTag(XmlReader reader)
{
Debug.Assert(reader != null);
// verify namespace and lack of attributes
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) > 0 ||
String.CompareOrdinal(reader.NamespaceURI, SignedXml.XmlDsigNamespaceUrl) != 0 ||
reader.Depth != 3)
{
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
// there are no legal attributes and the only content must be text
if (reader.HasAttributes || (reader.Read() && reader.MoveToContent() != XmlNodeType.Text))
{
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
// get the Value
return(reader.ReadString());
}
/// <summary>
/// Get the part uri and it's content type from the current Reference tag
/// </summary>
/// <param name="reader"></param>
/// <param name="contentType">contentType extracted from the query portion of the Uri</param>
/// <returns>PackagePart uri and contentType</returns>
private static Uri ParsePartUri(XmlReader reader, out ContentType contentType)
{
// should be a relative Package uri with a query portion that contains the ContentType
contentType = ContentType.Empty;
Uri partUri = null;
// must be one and only one attribute
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) == 1)
{
string uriAttrValue = reader.GetAttribute(XTable.Get(XTable.ID.UriAttrName));
if (uriAttrValue != null)
{
partUri = ParsePartUriAttribute(uriAttrValue, out contentType);
}
}
// will be null if we had no success
if (partUri == null)
{
throw new XmlException(SR.Get(SRID.RequiredXmlAttributeMissing, XTable.Get(XTable.ID.UriAttrName)));
}
return(partUri);
}
// Deserialize properties part.
private void ParseCorePropertyPart(PackagePart part)
{
Stream stream = part.GetStream(FileMode.Open, FileAccess.Read);
// Create a reader that uses _nameTable so as to use the set of tag literals
// in effect as a set of atomic identifiers.
XmlTextReader reader = new XmlTextReader(stream, _nameTable);
//Prohibit DTD from the markup as per the OPC spec
reader.ProhibitDtd = true;
//This method expects the reader to be in ReadState.Initial.
//It will make the first read call.
PackagingUtilities.PerformInitailReadAndVerifyEncoding(reader);
//Note: After the previous method call the reader should be at the first tag in the markup.
//MoveToContent - Skips over the following - ProcessingInstruction, DocumentType, Comment, Whitespace, or SignificantWhitespace
//If the reader is currently at a content node then this function call is a no-op
if (reader.MoveToContent() != XmlNodeType.Element ||
(object)reader.NamespaceURI != PackageXmlStringTable.GetXmlStringAsObject(PackageXmlEnum.PackageCorePropertiesNamespace) ||
(object)reader.LocalName != PackageXmlStringTable.GetXmlStringAsObject(PackageXmlEnum.CoreProperties))
{
throw new XmlException(SR.Get(SRID.CorePropertiesElementExpected),
null, reader.LineNumber, reader.LinePosition);
}
// The schema is closed and defines no attributes on the root element.
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) != 0)
{
throw new XmlException(SR.Get(SRID.PropertyWrongNumbOfAttribsDefinedOn, reader.Name),
null, reader.LineNumber, reader.LinePosition);
}
// Iterate through property elements until EOF. Note the proper closing of all
// open tags is checked by the reader itself.
// This loop deals only with depth-1 start tags. Handling of element content
// is delegated to dedicated functions.
int attributesCount;
while (reader.Read() && reader.MoveToContent() != XmlNodeType.None)
{
// Ignore end-tags. We check element errors on opening tags.
if (reader.NodeType == XmlNodeType.EndElement)
{
continue;
}
// Any content markup that is not an element here is unexpected.
if (reader.NodeType != XmlNodeType.Element)
{
throw new XmlException(SR.Get(SRID.PropertyStartTagExpected),
null, reader.LineNumber, reader.LinePosition);
}
// Any element below the root should open at level 1 exclusively.
if (reader.Depth != 1)
{
throw new XmlException(SR.Get(SRID.NoStructuredContentInsideProperties),
null, reader.LineNumber, reader.LinePosition);
}
attributesCount = PackagingUtilities.GetNonXmlnsAttributeCount(reader);
// Property elements can occur in any order (xsd:all).
object localName = reader.LocalName;
PackageXmlEnum xmlStringIndex = PackageXmlStringTable.GetEnumOf(localName);
String valueType = PackageXmlStringTable.GetValueType(xmlStringIndex);
if (Array.IndexOf(_validProperties, xmlStringIndex) == -1) // An unexpected element is an error.
{
throw new XmlException(
SR.Get(SRID.InvalidPropertyNameInCorePropertiesPart, reader.LocalName),
null, reader.LineNumber, reader.LinePosition);
}
// Any element not in the valid core properties namespace is unexpected.
// The following is an object comparison, not a string comparison.
if ((object)reader.NamespaceURI != PackageXmlStringTable.GetXmlStringAsObject(PackageXmlStringTable.GetXmlNamespace(xmlStringIndex)))
{
throw new XmlException(SR.Get(SRID.UnknownNamespaceInCorePropertiesPart),
null, reader.LineNumber, reader.LinePosition);
}
if (String.CompareOrdinal(valueType, "String") == 0)
{
// The schema is closed and defines no attributes on this type of element.
if (attributesCount != 0)
{
throw new XmlException(SR.Get(SRID.PropertyWrongNumbOfAttribsDefinedOn, reader.Name),
null, reader.LineNumber, reader.LinePosition);
}
RecordNewBinding(xmlStringIndex, GetStringData(reader), true /*initializing*/, reader);
}
else if (String.CompareOrdinal(valueType, "DateTime") == 0)
{
int allowedAttributeCount = (object)reader.NamespaceURI ==
PackageXmlStringTable.GetXmlStringAsObject(PackageXmlEnum.DublinCoreTermsNamespace)
? 1 : 0;
// The schema is closed and defines no attributes on this type of element.
if (attributesCount != allowedAttributeCount)
{
throw new XmlException(SR.Get(SRID.PropertyWrongNumbOfAttribsDefinedOn, reader.Name),
null, reader.LineNumber, reader.LinePosition);
}
if (allowedAttributeCount != 0)
{
ValidateXsiType(reader,
PackageXmlStringTable.GetXmlStringAsObject(PackageXmlEnum.DublinCoreTermsNamespace),
_w3cdtf);
}
RecordNewBinding(xmlStringIndex, GetDateData(reader), true /*initializing*/, reader);
}
else // An unexpected element is an error.
{
Invariant.Assert(false, "Unknown value type for properties");
}
}
}
/// <summary>
/// Parses Transforms tag
/// </summary>
/// <param name="reader">node to parse</param>
/// <param name="partUri">Part Uri for the part owning the relationships</param>
/// <param name="relationshipSelectors">allocates and returns a list of
/// PackageRelationshipSelectors if Relationship transform</param>
/// <returns>ordered list of Transform names</returns>
private static List <String> ParseTransformsTag(XmlReader reader, Uri partUri, ref List <PackageRelationshipSelector> relationshipSelectors)
{
// # reference that signs multiple PackageRelationships
// <Reference URI="/shared/_rels/image.jpg.rels?ContentType=image/jpg">
// <Transforms>
// <Transform Algorithm="http://schemas.openxmlformats.org/package/2006/RelationshipTransform">
// <RelationshipReference SourceId="1" />
// <RelationshipReference SourceId="2" />
// <RelationshipReference SourceId="8" />
// </Transform>
// <Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
// </Transforms>
// <DigestMethod Algorithm="sha1" />
// <DigestValue>... </DigestValue>
// </Reference>
// verify lack of attributes
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) != 0)
{
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
List <String> transforms = null;
bool relationshipTransformFound = false;
int transformsCountWhenRelationshipTransformFound = 0;
// Look for transforms.
// There are currently only 3 legal transforms which can be arranged in any
// combination.
while (reader.Read() && (reader.MoveToContent() == XmlNodeType.Element))
{
String transformName = null;
// at this level, all tags must be Transform tags
if (reader.Depth != 4 ||
String.CompareOrdinal(reader.NamespaceURI, SignedXml.XmlDsigNamespaceUrl) != 0 ||
String.CompareOrdinal(reader.LocalName, XTable.Get(XTable.ID.TransformTagName)) != 0)
{
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
// inspect the Algorithm attribute to determine the type of transform
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) == 1)
{
transformName = reader.GetAttribute(XTable.Get(XTable.ID.AlgorithmAttrName));
}
// legal transform name?
if ((transformName != null) && (transformName.Length > 0))
{
// what type of transform?
if (String.CompareOrdinal(transformName, XTable.Get(XTable.ID.RelationshipsTransformName)) == 0)
{
if (!relationshipTransformFound)
{
// relationship transform
ParseRelationshipsTransform(reader, partUri, ref relationshipSelectors);
if (transforms == null)
{
transforms = new List <String>();
}
transforms.Add(transformName);
relationshipTransformFound = true;
transformsCountWhenRelationshipTransformFound = transforms.Count;
continue; // success
}
else
{
throw new XmlException(SR.Get(SRID.MultipleRelationshipTransformsFound));
}
}
else
{
// non-Relationship transform should have no children
if (reader.IsEmptyElement)
{
if (transforms == null)
{
transforms = new List <String>();
}
if (XmlDigitalSignatureProcessor.IsValidXmlCanonicalizationTransform(transformName))
{
transforms.Add(transformName); // return it
continue; // success
}
else
{
throw new InvalidOperationException(SR.Get(SRID.UnsupportedTransformAlgorithm));
}
}
}
}
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
if (transforms.Count == 0)
{
throw new XmlException(SR.Get(SRID.XmlSignatureParseError));
}
//If we found another transform after the Relationship transform, it will be validated earlier
//in this method to make sure that its a supported xml canonicalization algorithm and so we can
//simplify this test condition - As per the OPC spec - Relationship transform must be followed
//by a canonicalization algorithm.
if (relationshipTransformFound && (transforms.Count == transformsCountWhenRelationshipTransformFound))
{
throw new XmlException(SR.Get(SRID.RelationshipTransformNotFollowedByCanonicalizationTransform));
}
return(transforms);
}
//-----------------------------------------------------------------------------
//
// Private Methods
//
//-----------------------------------------------------------------------------
/// <summary>
/// Parse the SignatureTime tag
/// </summary>
/// <param name="reader">NodeReader positioned at the SignatureProperty tag</param>
/// <param name="timeFormat">format found</param>
/// <exception cref="XmlException">illegal format</exception>
/// <returns>signing time</returns>
private static DateTime ParseSignatureTimeTag(XmlReader reader, out String timeFormat)
{
//There are no attributes on all the three tags that we parse in this method
//<SignatureTime>, <Format>, <Value>
int expectedAttributeCount = 0;
string opcSignatureNameSpace = XTable.Get(XTable.ID.OpcSignatureNamespace);
string signaturePropertyTag = XTable.Get(XTable.ID.SignaturePropertyTagName);
string signatureTimeTag = XTable.Get(XTable.ID.SignatureTimeTagName);
string timeValueTagName = XTable.Get(XTable.ID.SignatureTimeValueTagName);
string timeFormatTagName = XTable.Get(XTable.ID.SignatureTimeFormatTagName);
// <SignatureTime> must be one of <Format> or <Time>
timeFormat = null;
string timeValue = null;
//Look for <SignatureTime> Tag
if (reader.Read() &&
reader.MoveToContent() == XmlNodeType.Element &&
(String.CompareOrdinal(reader.NamespaceURI, opcSignatureNameSpace) == 0) &&
(String.CompareOrdinal(reader.LocalName, signatureTimeTag) == 0) &&
reader.Depth == 3 &&
PackagingUtilities.GetNonXmlnsAttributeCount(reader) == expectedAttributeCount)
{
while (reader.Read())
{
if (String.CompareOrdinal(reader.NamespaceURI, opcSignatureNameSpace) == 0 &&
reader.MoveToContent() == XmlNodeType.Element &&
reader.Depth == 4)
{
// which tag do we have?
if ((String.CompareOrdinal(reader.LocalName, timeValueTagName) == 0) &&
PackagingUtilities.GetNonXmlnsAttributeCount(reader) == expectedAttributeCount)
{
if (timeValue == null &&
reader.Read() &&
reader.MoveToContent() == XmlNodeType.Text &&
reader.Depth == 5)
{
//After reading the content, the reader progresses to the next element.
//So after this method is called, the reader is positioned at the
//EndElement corresponding to Value tag - </Value>
// Note: ReadContentAsString will return String.Empty but never null
timeValue = reader.ReadContentAsString();
Debug.Assert(reader.NodeType == XmlNodeType.EndElement);
}
else
{
//This would happen if we found more than one Value tags or if there
//are other nested elements of if they are of a different XmlNodeType type
throw new XmlException(SR.PackageSignatureCorruption);
}
}
else if ((String.CompareOrdinal(reader.LocalName, timeFormatTagName) == 0) &&
PackagingUtilities.GetNonXmlnsAttributeCount(reader) == expectedAttributeCount)
{
if (timeFormat == null &&
reader.Read() &&
reader.MoveToContent() == XmlNodeType.Text &&
reader.Depth == 5)
{
//After reading the content, the reader progresses to the next element.
//So after this method is called, the reader is positioned at the
//EndElement corresponding to Format tag - </Format>
// Note: ReadContentAsString will return String.Empty but never null
timeFormat = reader.ReadContentAsString();
Debug.Assert(reader.NodeType == XmlNodeType.EndElement);
}
else
{
//This would happen if we found more than one Format tags or if there
//are other nested elements of if they are of a different XmlNodeType type
throw new XmlException(SR.PackageSignatureCorruption);
}
}
else
{
//If we encounter any tag other than <Format> or <Time> nested within the <SignatureTime> tag
throw new XmlException(SR.PackageSignatureCorruption);
}
}
else
//If we have encountered the end tag for the <SignatureTime> tag
//then we are done parsing the tag, and we can stop the parsing.
if (String.CompareOrdinal(signatureTimeTag, reader.LocalName) == 0 &&
(reader.NodeType == XmlNodeType.EndElement))
{
//We must find a </SignatureProperty> tag at this point,
//else it could be that there are more SignatureTime or
//other tags nested here and that is an error.
if (reader.Read() &&
reader.MoveToContent() == XmlNodeType.EndElement &&
String.CompareOrdinal(signaturePropertyTag, reader.LocalName) == 0)
{
break;
}
else
{
throw new XmlException(SR.PackageSignatureCorruption);
}
}
else
{
// if we do not find the nested elements as expected
throw new XmlException(SR.PackageSignatureCorruption);
}
}
}
else
{
throw new XmlException(SR.Format(SR.RequiredTagNotFound, signatureTimeTag));
}
// generate an equivalent DateTime object
if (timeValue != null && timeFormat != null)
{
return(XmlFormattedTimeToDateTime(timeValue, timeFormat));
}
else
{
throw new XmlException(SR.PackageSignatureCorruption);
}
}
/// <summary>
/// Parse PackageRelationship Stream
/// </summary>
/// <param name="part">relationship part</param>
/// <exception cref="XmlException">Thrown if XML is malformed</exception>
private void ParseRelationshipPart(PackagePart part)
{
//We can safely open the stream as FileAccess.Read, as this code
//should only be invoked if the Package has been opened in Read or ReadWrite mode.
Debug.Assert(_package.FileOpenAccess == FileAccess.Read || _package.FileOpenAccess == FileAccess.ReadWrite,
"This method should only be called when FileAccess is Read or ReadWrite");
using (Stream s = part.GetStream(FileMode.Open, FileAccess.Read))
{
// load from the relationship part associated with the given part
using (XmlTextReader baseReader = new XmlTextReader(s))
{
baseReader.WhitespaceHandling = WhitespaceHandling.None;
//Prohibit DTD from the markup as per the OPC spec
baseReader.ProhibitDtd = true;
using (XmlCompatibilityReader reader = new XmlCompatibilityReader(baseReader, RelationshipKnownNamespaces))
{
//This method expects the reader to be in ReadState.Initial.
//It will make the first read call.
PackagingUtilities.PerformInitailReadAndVerifyEncoding(baseReader);
//Note: After the previous method call the reader should be at the first tag in the markup.
//MoveToContent - Skips over the following - ProcessingInstruction, DocumentType, Comment, Whitespace, or SignificantWhitespace
//If the reader is currently at a content node then this function call is a no-op
reader.MoveToContent();
// look for our tag and namespace pair - throw if other elements are encountered
// Make sure that the current node read is an Element
if (reader.NodeType == XmlNodeType.Element &&
(reader.Depth == 0) &&
(String.CompareOrdinal(RelationshipsTagName, reader.LocalName) == 0) &&
(String.CompareOrdinal(PackagingUtilities.RelationshipNamespaceUri, reader.NamespaceURI) == 0))
{
ThrowIfXmlBaseAttributeIsPresent(reader);
//There should be a namespace Attribute present at this level.
//Also any other attribute on the <Relationships> tag is an error including xml: and xsi: attributes
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) > 0)
{
throw new XmlException(SR.Get(SRID.RelationshipsTagHasExtraAttributes), null, reader.LineNumber, reader.LinePosition);
}
// start tag encountered for Relationships
// now parse individual Relationship tags
while (reader.Read())
{
//Skips over the following - ProcessingInstruction, DocumentType, Comment, Whitespace, or SignificantWhitespace
//If the reader is currently at a content node then this function call is a no-op
reader.MoveToContent();
//If MoveToContent() takes us to the end of the content
if (reader.NodeType == XmlNodeType.None)
{
continue;
}
if (reader.NodeType == XmlNodeType.Element &&
(reader.Depth == 1) &&
(String.CompareOrdinal(RelationshipTagName, reader.LocalName) == 0) &&
(String.CompareOrdinal(PackagingUtilities.RelationshipNamespaceUri, reader.NamespaceURI) == 0))
{
ThrowIfXmlBaseAttributeIsPresent(reader);
int expectedAttributesCount = 3;
string targetModeAttributeValue = reader.GetAttribute(TargetModeAttributeName);
if (targetModeAttributeValue != null)
{
expectedAttributesCount++;
}
//check if there are expected number of attributes.
//Also any other attribute on the <Relationship> tag is an error including xml: and xsi: attributes
if (PackagingUtilities.GetNonXmlnsAttributeCount(reader) == expectedAttributesCount)
{
ProcessRelationshipAttributes(reader);
//Skip the EndElement for Relationship
if (!reader.IsEmptyElement)
{
ProcessEndElementForRelationshipTag(reader);
}
}
else
{
throw new XmlException(SR.Get(SRID.RelationshipTagDoesntMatchSchema), null, reader.LineNumber, reader.LinePosition);
}
}
else
if (!(String.CompareOrdinal(RelationshipsTagName, reader.LocalName) == 0 && (reader.NodeType == XmlNodeType.EndElement)))
{
throw new XmlException(SR.Get(SRID.UnknownTagEncountered), null, reader.LineNumber, reader.LinePosition);
}
}
}
else
{
throw new XmlException(SR.Get(SRID.ExpectedRelationshipsElementTag), null, reader.LineNumber, reader.LinePosition);
}
}
}
}
}