xml_sec/xmlenc/
mod.rs

1//! XML Encryption (XMLEnc).
2//!
3//! Implements [XML Encryption Syntax and Processing](https://www.w3.org/TR/xmlenc-core1/).
4//!
5//! `EncryptedDataBuilder` encrypts opaque bytes, XML elements, XML content, or
6//! a selected node in a caller-owned document. It supports direct AES content
7//! keys and generated session keys wrapped independently for one or more
8//! RSA-OAEP or AES-KW recipients. The reciprocal decrypt APIs accept the same
9//! inline `CipherValue` profile.
10//!
11//! External `CipherReference` resources are outside this profile. Optional
12//! `legacy-algorithms` adds independently policy-gated RSA-1.5 and TripleDES
13//! mechanisms; it does not grant permission or authenticate CBC content.
14#![doc = include_str!("../../docs/xmlenc.md")]
15
16use crate::xml::dom::Node;
17
18mod agreement;
19mod encapsulation;
20pub use encapsulation::EncapsulationDecryptor;
21mod cipher_reference;
22pub use agreement::{AgreementDecryptor, AgreementMethod};
23mod decrypt;
24pub use cipher_reference::CipherReferenceContext;
25mod derived_key;
26pub(crate) use decrypt::validate_key_len;
27pub use derived_key::DerivedKey;
28mod encrypt;
29mod hkdf_agreement;
30mod key_derivation;
31pub use hkdf_agreement::{HkdfAgreement, parse_hkdf_agreement_method};
32mod key_establishment_budget;
33pub use key_establishment_budget::KeyEstablishmentBudget;
34mod parse;
35mod types;
36
37pub use decrypt::{
38    DecryptContext, DecryptionKeyResolver, DerivedKeyDecryptor, DerivedKeyInput,
39    DocumentDecryptionOptions, KekDecryptor, KeyCandidateBudget, KeyEncryptionKeySource,
40    OpaqueContentKeyResolver, OpaqueKekDecryptor, PrivateKeyDecryptor, SymmetricKeyDecryptor,
41    decrypt, decrypt_data, decrypt_document, decrypt_document_with_options,
42};
43pub use encrypt::{
44    EncryptedDataBuilder, validate_key_transport_recipient, validate_rsa_recipient_key,
45};
46pub use key_derivation::{
47    ConcatKdfField, KeyDerivationMethod, parse_key_derivation_method,
48    parse_key_derivation_method_with_backend,
49};
50pub use parse::{
51    EncryptedDataInspection, EncryptedDataTemplate, inspect_encrypted_data_node_with_context,
52    inspect_encrypted_data_template_node_with_context, parse_encrypted_data,
53    parse_encrypted_data_node_with_context, parse_encrypted_data_node_with_policy,
54    parse_encrypted_data_node_with_policy_and_backend,
55    parse_encrypted_data_template_node_with_policy,
56    parse_encrypted_data_template_node_with_policy_and_backend,
57};
58pub use types::{
59    CipherData, DataEncryptionAlgorithm, DecryptedContent, DocumentEncryptionOptions,
60    EncryptedData, EncryptedDataType, EncryptedKey, EncryptionKeySources, EncryptionMethod,
61    EncryptionRecipient, EncryptionResult, KeyTransportAlgorithm, KeyWrapAlgorithm,
62    OaepDigestAlgorithm, ReferenceList, ReplacementMode, RsaOaepParameters, XmlEncError,
63};
64
65fn map_document_error(
66    error: crate::document::XmlDocumentError,
67    settings: crate::document::DocumentParseSettings,
68) -> XmlEncError {
69    match error.into_policy_violation(settings) {
70        Ok(error) => XmlEncError::Policy(error),
71        Err(crate::document::XmlDocumentError::Parse(error)) => XmlEncError::XmlParse(error),
72        Err(crate::document::XmlDocumentError::ProjectedNodeLimit { maximum }) => {
73            crate::policy::PolicyViolation::ResourceLimit {
74                resource: crate::policy::resource_name::XML_NODES,
75                maximum,
76                actual: maximum.saturating_add(1),
77            }
78            .into()
79        }
80        Err(error) => XmlEncError::Document(error),
81    }
82}
83
84fn has_single_element_with_boundary_trivia(parent: Node<'_, '_>) -> bool {
85    let mut element_count = 0;
86    for node in parent.children() {
87        if node.is_element() {
88            element_count += 1;
89            if element_count > 1 {
90                return false;
91            }
92        } else if node.is_comment() {
93            continue;
94        } else if node.is_text() {
95            // XML permits boundary whitespace around a document element; processing
96            // instructions and every other node kind are unsafe replacement payloads.
97            if !node.text().is_some_and(|text| {
98                text.chars()
99                    .all(|character| matches!(character, ' ' | '\t' | '\n' | '\r'))
100            }) {
101                return false;
102            }
103        } else {
104            return false;
105        }
106    }
107    element_count == 1
108}
109
110#[cfg(test)]
111mod tests {
112    use super::*;
113    use crate::document::{DocumentParseSettings, XmlDocumentError};
114
115    #[test]
116    fn document_errors_have_one_xmlenc_policy_mapping() {
117        // Borrowed parsing and owned mutation must expose identical typed
118        // resource failures rather than depending on their entry-point mapper.
119        let settings = DocumentParseSettings::new_with_depth(false, 8, 3, 128);
120        assert!(matches!(
121            map_document_error(
122                XmlDocumentError::DocumentTooDeep {
123                    maximum: 3,
124                    actual: 4,
125                },
126                settings,
127            ),
128            XmlEncError::Policy(crate::policy::PolicyViolation::ResourceLimit {
129                resource: crate::policy::resource_name::XML_DEPTH,
130                maximum: 3,
131                actual: 4,
132            })
133        ));
134        assert!(matches!(
135            map_document_error(
136                XmlDocumentError::ProjectedNodeLimit { maximum: 8 },
137                settings,
138            ),
139            XmlEncError::Policy(crate::policy::PolicyViolation::ResourceLimit {
140                resource: crate::policy::resource_name::XML_NODES,
141                maximum: 8,
142                actual: 9,
143            })
144        ));
145    }
146}
xml_sec/xmlenc/mod.rs

xml_sec/xmlenc/
mod.rs
