Merge pull request #14 from apple/dn-cms-asn1

dnadoba · web-flow · commit 3a6e5c8564f6 · 2023-02-02T15:44:57.000+01:00
Cryptographic Message Syntax ASN.1 de/serialisation
diff --git a/Package.swift b/Package.swift
@@ -31,8 +31,8 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/apple/swift-crypto.git", from: "2.2.1"),
         // swift-asn1 repo is private, so we can't access it anonymously yet
-        // .package(url: "https://github.com/apple/swift-asn1.git", .upToNextMinor(from: "0.3.0")),
-        .package(url: "git@github.com:apple/swift-asn1.git", .upToNextMinor(from: "0.3.0")),
+        // .package(url: "https://github.com/apple/swift-asn1.git", .upToNextMinor(from: "0.4.0")),
+        .package(url: "git@github.com:apple/swift-asn1.git", .upToNextMinor(from: "0.4.0")),
         .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
     ],
     targets: [
diff --git a/Sources/X509/CryptographicMessageSyntax/CMSContentInfo.swift b/Sources/X509/CryptographicMessageSyntax/CMSContentInfo.swift
@@ -14,26 +14,70 @@
 
 import SwiftASN1
 
+extension ASN1ObjectIdentifier {
+    /// Cryptographic Message Syntax (CMS) Signed Data.
+    ///
+    /// ASN.1 definition:
+    /// ```
+    /// id-signedData OBJECT IDENTIFIER ::= { iso(1) member-body(2)
+    ///    us(840) rsadsi(113549) pkcs(1) pkcs7(7) 2 }
+    /// ```
+    static let cmsSignedData: ASN1ObjectIdentifier = [1, 2, 840, 113549, 1, 7, 2]
+}
+
 /// ``ContentInfo`` is defined in ASN.1 as:
 /// ```
 /// ContentInfo ::= SEQUENCE {
 ///   contentType ContentType,
 ///   content [0] EXPLICIT ANY DEFINED BY contentType }
 /// ContentType ::= OBJECT IDENTIFIER
 /// ```
-struct CMSContentInfo {
+struct CMSContentInfo: DERImplicitlyTaggable, Hashable {
+    static var defaultIdentifier: ASN1Identifier {
+        .sequence
+    }
+    
     var contentType: ASN1ObjectIdentifier
     var content: ASN1Any
+    
+    init(contentType: ASN1ObjectIdentifier, content: ASN1Any) {
+        self.contentType = contentType
+        self.content = content
+    }
+    
+    init(derEncoded rootNode: ASN1Node, withIdentifier identifier: ASN1Identifier) throws {
+        self = try DER.sequence(rootNode, identifier: identifier) { nodes in
+            let contentType = try ASN1ObjectIdentifier(derEncoded: &nodes)
+
+            let content = try DER.explicitlyTagged(&nodes, tagNumber: 0, tagClass: .contextSpecific) { node in
+                ASN1Any(derEncoded: node)
+            }
+            return .init(contentType: contentType, content: content)
+        }
+    }
+
+    func serialize(into coder: inout DER.Serializer, withIdentifier identifier: ASN1Identifier) throws {
+        try coder.appendConstructedNode(identifier: identifier) { coder in
+            try coder.serialize(contentType)
+            try coder.serialize(explicitlyTaggedWithTagNumber: 0, tagClass: .contextSpecific) { coder in
+                try coder.serialize(content)
+            }
+        }
+    }
 }
 
 extension CMSContentInfo {
-    init(_ signedData: CMSSignedData) {
-        fatalError("TODO: not implemented")
+    init(_ signedData: CMSSignedData) throws {
+        self.contentType = .cmsSignedData
+        self.content = try ASN1Any(erasing: signedData)
     }
     
     var signedData: CMSSignedData? {
         get throws {
-            fatalError("TODO: not implemented")
+            guard contentType == .cmsSignedData else {
+                return nil
+            }
+            return try CMSSignedData(asn1Any: content)
         }
     }
 }
diff --git a/Sources/X509/CryptographicMessageSyntax/CMSEncapsulatedContentInfo.swift b/Sources/X509/CryptographicMessageSyntax/CMSEncapsulatedContentInfo.swift
@@ -21,7 +21,38 @@ import SwiftASN1
 ///   eContent [0] EXPLICIT OCTET STRING OPTIONAL }
 /// ContentType ::= OBJECT IDENTIFIER
 /// ```
-struct CMSEncapsulatedContentInfo {
+struct CMSEncapsulatedContentInfo: DERImplicitlyTaggable, Hashable {
+    static var defaultIdentifier: ASN1Identifier {
+        .sequence
+    }
+    
     var eContentType: ASN1ObjectIdentifier
     var eContent: ASN1OctetString?
+    
+    init(eContentType: ASN1ObjectIdentifier, eContent: ASN1OctetString? = nil) {
+        self.eContentType = eContentType
+        self.eContent = eContent
+    }
+    
+    init(derEncoded rootNode: ASN1Node, withIdentifier identifier: ASN1Identifier) throws {
+        self = try DER.sequence(rootNode, identifier: identifier) { nodes in
+            let eContentType = try ASN1ObjectIdentifier(derEncoded: &nodes)
+            let eContent = try DER.optionalExplicitlyTagged(&nodes, tagNumber: 0, tagClass: .contextSpecific) { node in
+                try ASN1OctetString(derEncoded: node)
+            }
+            
+            return .init(eContentType: eContentType, eContent: eContent)
+        }
+    }
+    
+    func serialize(into coder: inout DER.Serializer, withIdentifier identifier: ASN1Identifier) throws {
+        try coder.appendConstructedNode(identifier: identifier, { coder in
+            try coder.serialize(eContentType)
+            if let eContent {
+                try coder.serialize(explicitlyTaggedWithTagNumber: 0, tagClass: .contextSpecific) { coder in
+                    try coder.serialize(eContent)
+                }
+            }
+        })
+    }
 }
diff --git a/Sources/X509/CryptographicMessageSyntax/CMSIssuerAndSerialNumber.swift b/Sources/X509/CryptographicMessageSyntax/CMSIssuerAndSerialNumber.swift
@@ -22,7 +22,34 @@ import SwiftASN1
 /// ```
 /// The definition of `Name` is taken from X.501 [X.501-88], and the
 /// definition of `CertificateSerialNumber` is taken from X.509 [X.509-97].
-struct CMSIssuerAndSerialNumber {
+struct CMSIssuerAndSerialNumber: DERImplicitlyTaggable, Hashable {
+    static var defaultIdentifier: ASN1Identifier {
+        .sequence
+    }
+    
     var issuer: DistinguishedName
     var serialNumber: Certificate.SerialNumber
+    
+    init(
+        issuer: DistinguishedName,
+        serialNumber: Certificate.SerialNumber
+    ) {
+        self.issuer = issuer
+        self.serialNumber = serialNumber
+    }
+    
+    init(derEncoded rootNode: ASN1Node, withIdentifier identifier: ASN1Identifier) throws {
+        self = try DER.sequence(rootNode, identifier: identifier) { nodes in
+            let issuer = try DistinguishedName(derEncoded: &nodes)
+            let serialNumber = try ArraySlice<UInt8>(derEncoded: &nodes)
+            return .init(issuer: issuer, serialNumber: .init(bytes: serialNumber))
+        }
+    }
+
+    func serialize(into coder: inout DER.Serializer, withIdentifier identifier: ASN1Identifier) throws {
+        try coder.appendConstructedNode(identifier: identifier) { coder in
+            try coder.serialize(self.issuer)
+            try coder.serialize(self.serialNumber.bytes)
+        }
+    }
 }
diff --git a/Sources/X509/CryptographicMessageSyntax/CMSSignedData.swift b/Sources/X509/CryptographicMessageSyntax/CMSSignedData.swift
@@ -27,6 +27,7 @@ import SwiftASN1
 /// DigestAlgorithmIdentifiers ::= SET OF DigestAlgorithmIdentifier
 /// DigestAlgorithmIdentifier ::= AlgorithmIdentifier
 /// SignerInfos ::= SET OF SignerInfo
+/// CertificateSet ::= SET OF CertificateChoices
 ///
 /// CertificateChoices ::= CHOICE {
 ///  certificate Certificate,
@@ -40,10 +41,88 @@ import SwiftASN1
 ///   otherCert ANY DEFINED BY otherCertFormat }
 /// ```
 /// - Note: At the moment we don't support `crls` (`RevocationInfoChoices`)
-struct CMSSignedData {
+struct CMSSignedData: DERImplicitlyTaggable, Hashable {
+    private enum Error: Swift.Error {
+        case multipleDigestAlgorithmsAreNotSupportedYet
+        case multipleSignerInfosAreNotSupportedYet
+    }
+    static var defaultIdentifier: ASN1Identifier {
+        .sequence
+    }
+    
     var version: CMSVersion
     var digestAlgorithms: [AlgorithmIdentifier]
     var encapContentInfo: CMSEncapsulatedContentInfo
     var certificates: [Certificate]?
     var signerInfos: [CMSSignerInfo]
+    
+    init(
+        version: CMSVersion,
+        digestAlgorithms: [AlgorithmIdentifier],
+        encapContentInfo: CMSEncapsulatedContentInfo,
+        certificates: [Certificate]?,
+        signerInfos: [CMSSignerInfo]
+    ) {
+        self.version = version
+        self.digestAlgorithms = digestAlgorithms
+        self.encapContentInfo = encapContentInfo
+        self.certificates = certificates
+        self.signerInfos = signerInfos
+    }
+    
+    init(derEncoded: ASN1Node, withIdentifier identifier: ASN1Identifier) throws {
+        self = try DER.sequence(derEncoded, identifier: identifier) { nodes in
+            let version = try CMSVersion(rawValue: Int.init(derEncoded: &nodes))
+            let digestAlgorithms = try DER.sequence(of: AlgorithmIdentifier.self, identifier: .set, nodes: &nodes)
+            // TODO: support multiple digest algorithms. For this we need to validate that the binary representation of each element is lexicographically sorted.
+            guard digestAlgorithms.count <= 1 else {
+                throw Error.multipleDigestAlgorithmsAreNotSupportedYet
+            }
+            
+            let encapContentInfo = try CMSEncapsulatedContentInfo(derEncoded: &nodes)
+            let certificates = try DER.optionalImplicitlyTagged(&nodes, tagNumber: 0, tagClass: .contextSpecific) { node in
+                // TODO: this is actually a SET OF so we need to verify that the binary representation of each element is lexicographically sorted.
+                try DER.sequence(of: Certificate.self, identifier: .init(tagWithNumber: 0, tagClass: .contextSpecific), rootNode: node)
+            }
+            
+            // we need to skip this node even though we don't support it
+            _ = DER.optionalImplicitlyTagged(&nodes, tagNumber: 1, tagClass: .contextSpecific) { _ in }
+            
+            let signerInfos = try DER.sequence(of: CMSSignerInfo.self, identifier: .set, nodes: &nodes)
+            
+            // TODO: support multiple signer infos. For this we need to validate that the binary representation of each element is lexicographically sorted.
+            guard signerInfos.count <= 1 else {
+                throw Error.multipleSignerInfosAreNotSupportedYet
+            }
+            
+            return .init(
+                version: version,
+                digestAlgorithms: digestAlgorithms,
+                encapContentInfo: encapContentInfo,
+                certificates: certificates,
+                signerInfos: signerInfos
+            )
+        }
+    }
+    
+    func serialize(into coder: inout DER.Serializer, withIdentifier identifier: ASN1Identifier) throws {
+        try coder.appendConstructedNode(identifier: identifier) { coder in
+            try coder.serialize(version.rawValue)
+            guard self.digestAlgorithms.count <= 1 else {
+                throw Error.multipleDigestAlgorithmsAreNotSupportedYet
+            }
+            // TODO: this is actually a SET OF. We need to sort the binary representation of each element lexicographically before encoding.
+            try coder.serializeSequenceOf(self.digestAlgorithms, identifier: .set)
+            try coder.serialize(self.encapContentInfo)
+            if let certificates {
+                // TODO: this is actually a SET OF. We need to sort the binary representation of each element lexicographically before encoding.
+                try coder.serializeSequenceOf(certificates, identifier: .init(tagWithNumber: 0, tagClass: .contextSpecific))
+            }
+            guard self.signerInfos.count <= 1 else {
+                throw Error.multipleSignerInfosAreNotSupportedYet
+            }
+            // TODO: this is actually a SET OF. We need to sort the binary representation of each element lexicographically before encoding.
+            try coder.serializeSequenceOf(self.signerInfos, identifier: .set)
+        }
+    }
 }
diff --git a/Sources/X509/CryptographicMessageSyntax/CMSSignerIdentifier.swift b/Sources/X509/CryptographicMessageSyntax/CMSSignerIdentifier.swift
@@ -20,7 +20,34 @@ import SwiftASN1
 ///   issuerAndSerialNumber IssuerAndSerialNumber,
 ///   subjectKeyIdentifier [0] SubjectKeyIdentifier }
 ///  ```
-enum CMSSignerIdentifier {
+enum CMSSignerIdentifier: DERParseable, DERSerializable, Hashable {
+    
+    private static let skiIdentifier = ASN1Identifier(tagWithNumber: 0, tagClass: .contextSpecific)
+    
     case issuerAndSerialNumber(CMSIssuerAndSerialNumber)
     case subjectKeyIdentifier(Certificate.Extensions.SubjectKeyIdentifier)
+    
+    init(derEncoded node: ASN1Node) throws {
+        switch node.identifier {
+        case CMSIssuerAndSerialNumber.defaultIdentifier:
+            self = try .issuerAndSerialNumber(.init(derEncoded: node))
+
+        case Self.skiIdentifier:
+            self = try .subjectKeyIdentifier(.init(keyIdentifier: .init(derEncoded: node, withIdentifier: Self.skiIdentifier)))
+
+        default:
+            throw ASN1Error.invalidASN1Object
+        }
+    }
+    
+    func serialize(into coder: inout DER.Serializer) throws {
+        switch self {
+        case .issuerAndSerialNumber(let issuerAndSerialNumber):
+            try issuerAndSerialNumber.serialize(into: &coder)
+
+        case .subjectKeyIdentifier(let subjectKeyIdentifier):
+            try subjectKeyIdentifier.keyIdentifier.serialize(into: &coder, withIdentifier: Self.skiIdentifier)
+            
+        }
+    }
 }
diff --git a/Sources/X509/CryptographicMessageSyntax/CMSSignerInfo.swift b/Sources/X509/CryptographicMessageSyntax/CMSSignerInfo.swift
@@ -33,11 +33,94 @@ import SwiftASN1
 /// then the `version` MUST be 1.  If the `SignerIdentifier` is `subjectKeyIdentifier`,
 /// then the `version` MUST be 3.
 /// - Note: At the moment we neither support `signedAttrs` (`SignedAttributes`) nor `unsignedAttrs` (`UnsignedAttributes`)
-struct CMSSignerInfo {
+struct CMSSignerInfo: DERImplicitlyTaggable, Hashable {
+    enum Error: Swift.Error {
+        case versionAndSignerIdentifierMismatch(String)
+    }
+    static var defaultIdentifier: ASN1Identifier {
+        .sequence
+    }
+    
     var version: CMSVersion
     var signerIdentifier: CMSSignerIdentifier
     var digestAlgorithm: AlgorithmIdentifier
     var signatureAlgorithm: AlgorithmIdentifier
     var signature: ASN1OctetString
+    
+    init(
+        signerIdentifier: CMSSignerIdentifier,
+        digestAlgorithm: AlgorithmIdentifier,
+        signatureAlgorithm: AlgorithmIdentifier,
+        signature: ASN1OctetString
+    ) {
+        switch signerIdentifier {
+        case .issuerAndSerialNumber:
+            self.version = .v1
+        case .subjectKeyIdentifier:
+            self.version = .v3
+        }
+        self.signerIdentifier = signerIdentifier
+        self.digestAlgorithm = digestAlgorithm
+        self.signatureAlgorithm = signatureAlgorithm
+        self.signature = signature
+    }
+    
+    init(
+        version: CMSVersion,
+        signerIdentifier: CMSSignerIdentifier,
+        digestAlgorithm: AlgorithmIdentifier,
+        signatureAlgorithm: AlgorithmIdentifier,
+        signature: ASN1OctetString
+    ) {
+        self.version = version
+        self.signerIdentifier = signerIdentifier
+        self.digestAlgorithm = digestAlgorithm
+        self.signatureAlgorithm = signatureAlgorithm
+        self.signature = signature
+    }
+    
+    init(derEncoded rootNode: ASN1Node, withIdentifier identifier: ASN1Identifier) throws {
+        self = try DER.sequence(rootNode, identifier: identifier) { nodes in
+            let version = try CMSVersion(rawValue: Int(derEncoded: &nodes))
+            let signerIdentifier = try CMSSignerIdentifier(derEncoded: &nodes)
+            switch signerIdentifier {
+            case .issuerAndSerialNumber:
+                guard version == .v1 else {
+                    throw Error.versionAndSignerIdentifierMismatch("expected \(CMSVersion.v1) but got \(version) where signerIdentifier is \(signerIdentifier)")
+                }
+            case .subjectKeyIdentifier:
+                guard version == .v3 else {
+                    throw Error.versionAndSignerIdentifierMismatch("expected \(CMSVersion.v3) but got \(version) where signerIdentifier is \(signerIdentifier)")
+                }
+            }
+            let digestAlgorithm = try AlgorithmIdentifier(derEncoded: &nodes)
+            
+            // we don't support signedAttrs yet but we still need to skip them
+            _ = DER.optionalImplicitlyTagged(&nodes, tagNumber: 0, tagClass: .contextSpecific) { _ in }
+            
+            let signatureAlgorithm = try AlgorithmIdentifier(derEncoded: &nodes)
+            let signature = try ASN1OctetString(derEncoded: &nodes)
+            
+            // we don't support unsignedAttrs yet but we still need to skip them
+            _ = DER.optionalImplicitlyTagged(&nodes, tagNumber: 1, tagClass: .contextSpecific) { _ in }
+            
+            return .init(
+                version: version,
+                signerIdentifier: signerIdentifier,
+                digestAlgorithm: digestAlgorithm,
+                signatureAlgorithm: signatureAlgorithm,
+                signature: signature
+            )
+        }
+    }
+    
+    func serialize(into coder: inout DER.Serializer, withIdentifier identifier: ASN1Identifier) throws {
+        try coder.appendConstructedNode(identifier: identifier) { coder in
+            try coder.serialize(self.version.rawValue)
+            try coder.serialize(self.signerIdentifier)
+            try coder.serialize(self.digestAlgorithm)
+            try coder.serialize(self.signatureAlgorithm)
+            try coder.serialize(self.signature)
+        }
+    }
 }
-
diff --git a/Tests/X509Tests/CMSTests.swift b/Tests/X509Tests/CMSTests.swift
