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import Foundation
import CEduVpnCommon
private extension Data {
/// Execute `body` with `GoSlice` pointing to `self`
/// - Important: `GoSlice` pointer must not be written to
func withSlice<ResultType>(_ body: (GoSlice) throws -> ResultType) rethrows -> ResultType {
// Could also use raw NSData.bytes, but then you have to be careful that the NSData must remain valid during the call
// This closure method guarantees this
try withUnsafeBytes { (pointer: UnsafeRawBufferPointer) -> ResultType in
// Note: UnsafeRawBufferPointer.startIndex will always be 0, see docs
// Cast to UnsafeMutableRawPointer, assumes it will not actually be written to
try body(GoSlice(data: UnsafeMutableRawPointer(mutating: pointer.baseAddress),
len: GoInt(pointer.count), cap: GoInt(pointer.count)))
}
}
}
private extension String {
/// Execute `body` with `GoSlice` pointing to UTF-8 bytes copied from `self`
func withSlice<ResultType>(_ body: (GoSlice) throws -> ResultType) rethrows -> ResultType {
try data(using: .utf8)!.withSlice(body)
}
}
public enum VerifyErr: Error, Equatable {
/// Expected file name is not one of the recognized values.
case ErrUnknownExpectedFileName
/// Signature is invalid (for the expected file type).
case ErrInvalidSignature
/// Signature was created with an unknown key and has not been verified.
case ErrInvalidSignatureUnknownKey
/// Signature has a timestamp lower than the specified minimum signing time.
case ErrTooOld
/// Other unknown error
case Unknown(code: GoInt8)
static func fromCode(_ code: GoInt8) -> VerifyErr {
precondition(code != 0)
switch code {
case 1: return ErrUnknownExpectedFileName
case 2: return ErrInvalidSignature
case 3: return ErrInvalidSignatureUnknownKey
case 4: return ErrTooOld
default: return Unknown(code: code)
}
}
}
/// Verifies the signature on the JSON server_list.json/organization_list.json file.
/// If the function returns, the signature is valid for the given file type.
///
/// - Parameters:
/// - signature: .minisig signature file contents.
/// - signedJson: Signed .json file contents.
/// - expectedFileName: The file type to be verified, one of "server_list.json" or "organization_list.json".
/// - minSignTime: Minimum time for signature. Should be set to at least the time of the previous signature.
/// - Throws: VerifyErr: If signature verification fails or `expectedFileName` is not one of the allowed values.
public func Verify(signature: Data, signedJson: Data, expectedFileName: String, minSignTime: Date) throws {
let result = signature.withSlice { signatureData in
signedJson.withSlice { jsonData in
expectedFileName.withSlice { expectedNameData in
CEduVpnCommon.Verify(signatureData, jsonData, expectedNameData, GoUint64(minSignTime.timeIntervalSince1970))
}
}
}
if result != 0 {
throw VerifyErr.fromCode(result)
}
}
/// Use for testing only, see Go documentation.
internal func InsecureTestingSetExtraKey(keyString: String) {
keyString.withSlice { keyData in
CEduVpnCommon.InsecureTestingSetExtraKey(keyData);
}
}
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