CryptoKit migration (#628)

* WIP. * WIP * WIP Edit * Key selection. * WIP * WIP * Proxy through * WIP * Remove verify. * Migration. * Comment * Add param * Semi-offering key * Ignore updates if test build. * Fix rsa public key gen * Messily fix RSA * Remove 1024 bit rsa * Cleanup * Cleanup * Clean out MLDSA refs for now * Dump notifier changes * Put back UI tweaks * Fixes.
2026-04-10 11:17:24 +02:00 · 2025-08-24 15:35:15 -07:00
parent 5b0135d694
commit 3d3d123484
38 changed files with 923 additions and 763 deletions
--- a/Sources/Packages/Sources/SecretKit/OpenSSH/OpenSSHPublicKeyWriter.swift
+++ b/Sources/Packages/Sources/SecretKit/OpenSSH/OpenSSHPublicKeyWriter.swift
@@ -0,0 +1,103 @@
+import Foundation
+import CryptoKit
+
+/// Generates OpenSSH representations of the public key sof secrets.
+public struct OpenSSHPublicKeyWriter: Sendable {
+
+    /// Initializes the writer.
+    public init() {
+    }
+
+    /// Generates an OpenSSH data payload identifying the secret.
+    /// - Returns: OpenSSH data payload identifying the secret.
+    public func data<SecretType: Secret>(secret: SecretType) -> Data {
+        switch secret.keyType.algorithm {
+        case .ecdsa:
+            // https://datatracker.ietf.org/doc/html/rfc5656#section-3.1
+            openSSHIdentifier(for: secret.keyType).lengthAndData +
+            ("nistp" + String(describing: secret.keyType.size)).lengthAndData +
+            secret.publicKey.lengthAndData
+        case .rsa:
+            // https://datatracker.ietf.org/doc/html/rfc4253#section-6.6
+            openSSHIdentifier(for: secret.keyType).lengthAndData +
+            rsaPublicKeyBlob(secret: secret)
+        }
+    }
+
+    /// Generates an OpenSSH string representation of the secret.
+    /// - Returns: OpenSSH string representation of the secret.
+    public func openSSHString<SecretType: Secret>(secret: SecretType) -> String {
+        let resolvedComment: String
+        if let comment = secret.publicKeyAttribution {
+            resolvedComment = comment
+        } else {
+            let dashedKeyName = secret.name.replacingOccurrences(of: " ", with: "-")
+            let dashedHostName = ["secretive", Host.current().localizedName, "local"]
+                .compactMap { $0 }
+                .joined(separator: ".")
+                .replacingOccurrences(of: " ", with: "-")
+            resolvedComment = "\(dashedKeyName)@\(dashedHostName)"
+        }
+        return [openSSHIdentifier(for: secret.keyType), data(secret: secret).base64EncodedString(), resolvedComment]
+            .compactMap { $0 }
+            .joined(separator: " ")
+    }
+
+    /// Generates an OpenSSH SHA256 fingerprint string.
+    /// - Returns: OpenSSH SHA256 fingerprint string.
+    public func openSSHSHA256Fingerprint<SecretType: Secret>(secret: SecretType) -> String {
+        // OpenSSL format seems to strip the padding at the end.
+        let base64 = Data(SHA256.hash(data: data(secret: secret))).base64EncodedString()
+        let paddingRange = base64.index(base64.endIndex, offsetBy: -2)..<base64.endIndex
+        let cleaned = base64.replacingOccurrences(of: "=", with: "", range: paddingRange)
+        return "SHA256:\(cleaned)"
+    }
+
+    /// Generates an OpenSSH MD5 fingerprint string.
+    /// - Returns: OpenSSH MD5 fingerprint string.
+    public func openSSHMD5Fingerprint<SecretType: Secret>(secret: SecretType) -> String {
+        Insecure.MD5.hash(data: data(secret: secret))
+            .compactMap { ("0" + String($0, radix: 16, uppercase: false)).suffix(2) }
+            .joined(separator: ":")
+    }
+
+}
+
+extension OpenSSHPublicKeyWriter {
+
+    /// The fully qualified OpenSSH identifier for the algorithm.
+    /// - Parameters:
+    ///   - algorithm: The algorithm to identify.
+    ///   - length: The key length of the algorithm.
+    /// - Returns: The OpenSSH identifier for the algorithm.
+    public func openSSHIdentifier(for keyType: KeyType) -> String {
+        switch (keyType.algorithm, keyType.size) {
+        case (.ecdsa, 256), (.ecdsa, 384):
+            "ecdsa-sha2-nistp" + String(describing: keyType.size)
+        case (.rsa, _):
+            "ssh-rsa"
+        default:
+            "unknown"
+        }
+    }
+
+}
+
+extension OpenSSHPublicKeyWriter {
+
+    public func rsaPublicKeyBlob<SecretType: Secret>(secret: SecretType) -> Data {
+        // Cheap way to pull out e and n as defined in https://datatracker.ietf.org/doc/html/rfc4253
+        // Keychain stores it as a thin ASN.1 wrapper with this format:
+        // [4 byte prefix][2 byte prefix][n][2 byte prefix][e]
+        // Rather than parse out the whole ASN.1 blob, we'll cheat and pull values directly since
+        // we only support one key type, and the keychain always gives it in a specific format.
+        let keySize = secret.keyType.size
+        guard secret.keyType.algorithm == .rsa && keySize == 2048 else { fatalError() }
+        let length = secret.keyType.size/8
+        let data = secret.publicKey
+        let n = Data(data[8..<(9+length)])
+        let e = Data(data[(2+9+length)...])
+        return e.lengthAndData + n.lengthAndData
+    }
+
+}