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Support for signing non XML data #238

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33 changes: 22 additions & 11 deletions signxml/processor.py
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Original file line number Diff line number Diff line change
Expand Up @@ -36,10 +36,18 @@ def parser(self):
return self._default_parser
return self._parser

def _fromstring(self, xml_string, **kwargs):
xml_node = etree.fromstring(xml_string, parser=self.parser, **kwargs)
for entity in xml_node.iter(etree.Entity):
raise InvalidInput("Entities are not supported in XML input")
def _fromstring(self, data, **kwargs):
try:
xml_node = etree.fromstring(data, parser=self.parser, **kwargs)
for entity in xml_node.iter(etree.Entity):
raise InvalidInput("Entities are not supported in XML input")
except etree.XMLSyntaxError as e:
logger.debug("Data to be signed is not well-formed XML: %s", data)
if isinstance(data, str):
# We have to convert string to bytes
data = data.encode("utf-8")
return data

return xml_node

def _tostring(self, xml_node, **kwargs):
Expand Down Expand Up @@ -117,13 +125,16 @@ def _c14n(self, nodes, algorithm: CanonicalizationMethod, inclusive_ns_prefixes=

c14n = b""
for node in nodes:
c14n += etree.tostring(
node,
method="c14n",
exclusive=exclusive,
with_comments=with_comments,
inclusive_ns_prefixes=inclusive_ns_prefixes,
)
if isinstance(node, bytes):
c14n += node
else:
c14n += etree.tostring(
node,
method="c14n",
exclusive=exclusive,
with_comments=with_comments,
inclusive_ns_prefixes=inclusive_ns_prefixes,
)
if exclusive is False and self.excise_empty_xmlns_declarations is True:
# Incorrect legacy behavior. See also:
# - https://github.com/XML-Security/signxml/issues/193
Expand Down
32 changes: 24 additions & 8 deletions signxml/signer.py
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Original file line number Diff line number Diff line change
Expand Up @@ -324,6 +324,13 @@ def _get_c14n_inputs_from_references(self, doc_root, references: List[SignatureR

def _unpack(self, data, references: List[SignatureReference]):
sig_root = Element(ds_tag("Signature"), nsmap=self.namespaces)
if isinstance(data, str):
data = data.encode("utf-8")
data_is_not_xml = True
elif isinstance(data, bytes):
data_is_not_xml = True
else:
data_is_not_xml = False
if self.construction_method == SignatureConstructionMethod.enveloped:
if isinstance(data, (str, bytes)):
raise InvalidInput("When using enveloped signature, **data** must be an XML element")
Expand Down Expand Up @@ -357,11 +364,16 @@ def _unpack(self, data, references: List[SignatureReference]):
elif self.construction_method == SignatureConstructionMethod.detached:
doc_root = self.get_root(data)
if references is None:
if data_is_not_xml:
raise InvalidInput("When using detached signature and data is not XML, **reference** has to be provided")
uri = "#{}".format(data.get("Id", data.get("ID", "object")))
references = [SignatureReference(URI=uri)]
c14n_inputs = [self.get_root(data)]
try:
c14n_inputs, references = self._get_c14n_inputs_from_references(doc_root, references)
try:
if data_is_not_xml:
c14n_inputs = [doc_root]
else:
c14n_inputs, references = self._get_c14n_inputs_from_references(doc_root, references)
except InvalidInput: # Dummy reference URI
c14n_inputs = [self.get_root(data)]
elif self.construction_method == SignatureConstructionMethod.enveloping:
Expand Down Expand Up @@ -400,13 +412,17 @@ def _build_sig(self, sig_root, references, c14n_inputs, inclusive_ns_prefixes):
if reference.inclusive_ns_prefixes is None:
reference = replace(reference, inclusive_ns_prefixes=inclusive_ns_prefixes)
reference_node = SubElement(signed_info, ds_tag("Reference"), URI=reference.URI)
transforms = SubElement(reference_node, ds_tag("Transforms"))
self._build_transforms_for_reference(transforms_node=transforms, reference=reference)
SubElement(reference_node, ds_tag("DigestMethod"), Algorithm=self.digest_alg.value)
if not isinstance(c14n_inputs[i], bytes):
transforms = SubElement(reference_node, ds_tag("Transforms"))
self._build_transforms_for_reference(transforms_node=transforms, reference=reference)
SubElement(reference_node, ds_tag("DigestMethod"), Algorithm=self.digest_alg.value)
digest_value = SubElement(reference_node, ds_tag("DigestValue"))
payload_c14n = self._c14n(
c14n_inputs[i], algorithm=reference.c14n_method, inclusive_ns_prefixes=reference.inclusive_ns_prefixes
)
if not isinstance(c14n_inputs[i], bytes):
payload_c14n = self._c14n(
c14n_inputs[i], algorithm=reference.c14n_method, inclusive_ns_prefixes=reference.inclusive_ns_prefixes
)
else:
payload_c14n = c14n_inputs[i]
digest = self._get_digest(payload_c14n, algorithm=self.digest_alg)
digest_value.text = b64encode(digest).decode()
signature_value = SubElement(sig_root, ds_tag("SignatureValue"))
Expand Down