Registry login interactive mode cannot read password/token over 128 c…

…hars long (#6562) (#6614)

* Registry login interactive mode cannot read password/token over 128 chars long

Motivation:
`swift package-registry login` in interactive mode truncates input when the provided password/token is more than 128 chars long. This is a limitation of `getpass`.

rdar://109372320

Modifications:
- Use `readpassphrase`, which allows custom input length, instead of `getpass`.
- Improve error message when the provided password/token is too long.
- Increase password/token length limit to 512 chars

* Continue using getpass on non-Darwin, non-Windows platforms

* include more details in Windows error messages

Sources/PackageRegistryTool/PackageRegistryTool+Auth.swift

@@ -22,26 +22,26 @@ import TSCBasic
 #if os(Windows)
 import WinSDK
 
-private func getpass(_ prompt: String) -> UnsafePointer<CChar> {
+private func readpassword(_ prompt: String) throws -> String {
  enum StaticStorage {
  static var buffer: UnsafeMutableBufferPointer<CChar> =
- .allocate(capacity: 255)
+ .allocate(capacity: SwiftPackageRegistryTool.Login.passwordBufferSize)
  }
 
  let hStdIn: HANDLE = GetStdHandle(STD_INPUT_HANDLE)
  if hStdIn == INVALID_HANDLE_VALUE {
- return UnsafePointer<CChar>(StaticStorage.buffer.baseAddress!)
+ throw StringError("unable to read input: GetStdHandle returns INVALID_HANDLE_VALUE")
  }
 
  var dwMode: DWORD = 0
  guard GetConsoleMode(hStdIn, &dwMode) else {
- return UnsafePointer<CChar>(StaticStorage.buffer.baseAddress!)
+ throw StringError("unable to read input: GetConsoleMode failed")
  }
 
  print(prompt, terminator: "")
 
  guard SetConsoleMode(hStdIn, DWORD(ENABLE_LINE_INPUT)) else {
- return UnsafePointer<CChar>(StaticStorage.buffer.baseAddress!)
+ throw StringError("unable to read input: SetConsoleMode failed")
  }
  defer { SetConsoleMode(hStdIn, dwMode) }
 
@@ -53,7 +53,37 @@ private func getpass(_ prompt: String) -> UnsafePointer<CChar> {
  &dwNumberOfCharsRead,
  nil
  )
- return UnsafePointer<CChar>(StaticStorage.buffer.baseAddress!)
+
+ let password = String(cString: UnsafePointer<CChar>(StaticStorage.buffer.baseAddress!))
+ guard password.count <= SwiftPackageRegistryTool.Login.maxPasswordLength else {
+ throw SwiftPackageRegistryTool.ValidationError
+ .credentialLengthLimitExceeded(SwiftPackageRegistryTool.Login.maxPasswordLength)
+ }
+ return password
+}
+#else
+private func readpassword(_ prompt: String) throws -> String {
+ let password: String
+
+ #if canImport(Darwin)
+ var buffer = [CChar](repeating: 0, count: SwiftPackageRegistryTool.Login.passwordBufferSize)
+
+ guard let passwordPtr = readpassphrase(prompt, &buffer, buffer.count, 0) else {
+ throw StringError("unable to read input")
+ }
+
+ password = String(cString: passwordPtr)
+ #else
+ // GNU C implementation of getpass has no limit on the password length
+ // (https://man7.org/linux/man-pages/man3/getpass.3.html)
+ password = String(cString: getpass(prompt))
+ #endif
+
+ guard password.count <= SwiftPackageRegistryTool.Login.maxPasswordLength else {
+ throw SwiftPackageRegistryTool.ValidationError
+ .credentialLengthLimitExceeded(SwiftPackageRegistryTool.Login.maxPasswordLength)
+ }
+ return password
 }
 #endif
 
@@ -63,6 +93,12 @@ extension SwiftPackageRegistryTool {
  abstract: "Log in to a registry"
  )
 
+ static let maxPasswordLength = 512
+ // Define a larger buffer size so we read more than allowed, and
+ // this way we can tell if the entered password is over the length
+ // limit. One space is for \0, another is for the "overflowing" char.
+ static let passwordBufferSize = Self.maxPasswordLength + 2
+
  @OptionGroup(visibility: .hidden)
  var globalOptions: GlobalOptions
 
@@ -140,7 +176,7 @@ extension SwiftPackageRegistryTool {
  saveChanges = false
  } else {
  // Prompt user for password
- storePassword = String(cString: getpass("Enter password for '\(storeUsername)': "))
+ storePassword = try readpassword("Enter password for '\(storeUsername)': ")
  }
  } else {
  authenticationType = .token
@@ -162,7 +198,7 @@ extension SwiftPackageRegistryTool {
  saveChanges = false
  } else {
  // Prompt user for token
- storePassword = String(cString: getpass("Enter access token: "))
+ storePassword = try readpassword("Enter access token: ")
  }
  }
 

Sources/PackageRegistryTool/PackageRegistryTool.swift

@@ -137,6 +137,7 @@ public struct SwiftPackageRegistryTool: ParsableCommand {
  case unknownRegistry
  case unknownCredentialStore
  case invalidCredentialStore(Error)
+ case credentialLengthLimitExceeded(Int)
  }
 
  static func getRegistriesConfig(_ swiftTool: SwiftTool) throws -> Workspace.Configuration.Registries {
@@ -181,6 +182,8 @@ extension SwiftPackageRegistryTool.ValidationError: CustomStringConvertible {
  return "no credential store available"
  case .invalidCredentialStore(let error):
  return "credential store is invalid: \(error.interpolationDescription)"
+ case .credentialLengthLimitExceeded(let limit):
+ return "password or access token must be \(limit) characters or less"
  }
  }
 }