Module: Tina4::Auth

Defined in:
lib/tina4/auth.rb

Constant Summary collapse

KEYS_DIR = 
".keys"
BLANK_SECRET_WARNING =

Single source of truth for the blank-secret warning, emitted identically from both the CI/prod boot path (ensure_dev_secret) and the lazy per-call resolver (hmac_secret). Actionable: names exactly what to set.

"Auth: TINA4_SECRET is not set — JWT signing is insecure. Set TINA4_SECRET " \
"to a random value (e.g. `openssl rand -hex 32`) in your environment or " \
".env before serving traffic. " \
"For LOCAL DEV, set TINA4_DEBUG=true and a per-machine secret is generated " \
"automatically into .env.local (gitignored). Seeing this warning means the " \
"run was NOT detected as dev - typically a container or CI without " \
"TINA4_DEBUG set, or TINA4_ENV=production."
HMAC_ALGORITHMS =

Supported JWT algorithms. HMAC only — the whole family ships in OpenSSL, so this stays zero-gem. The header's "alg" is now always the one we actually sign with: the digest is looked up here rather than hardcoded to SHA256. Mirrors the Python master's _HMAC_ALGORITHMS (a name -> digest map); the value is the digest CLASS and a fresh instance is made per signature, so nothing about the digest state is shared between calls or threads.

{
  "HS256" => OpenSSL::Digest::SHA256,
  "HS384" => OpenSSL::Digest::SHA384,
  "HS512" => OpenSSL::Digest::SHA512
}.freeze
JWT_LEEWAY_SECONDS =

Seconds of clock skew tolerated on the "nbf" (not-before) claim. Without this a token minted on one host and validated on another a second behind is rejected for no real reason; RFC 7519 explicitly allows "a small leeway".

60

Class Method Summary collapse

Class Method Details

.auth_handler(&block) ⇒ Object 



380
381
382
383
384
385
386
 
# File 'lib/tina4/auth.rb', line 380

def auth_handler(&block)
  if block_given?
    @custom_handler = block
  else
    @custom_handler || method(:default_auth_handler)
  end
end

.authenticate_request(headers, secret: nil, algorithm: nil) ⇒ Object

Extract and validate auth from request headers.

secret: and algorithm: are real overrides. algorithm: used to be accepted with a hardcoded "HS256" default and then dropped on the floor, so an explicit argument silently lost to TINA4_JWT_ALGORITHM — the precedence is now honoured here too (explicit > env > HS256).



346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
 
# File 'lib/tina4/auth.rb', line 346

def authenticate_request(headers, secret: nil, algorithm: nil)
  auth_header = headers["HTTP_AUTHORIZATION"] || headers["Authorization"] || ""
  return nil unless auth_header =~ /\ABearer\s+(.+)\z/i

  token = Regexp.last_match(1)

  # API_KEY bypass — timing-safe comparison via validate_api_key
  # (OpenSSL.fixed_length_secure_compare). Parity with Python's
  # authenticate_request (validate_api_key), PHP (hash_equals) and
  # Node (timingSafeEqual). Never use a plain `==` here — that leaks the
  # key length/prefix through comparison timing.
  if validate_api_key(token)
    return { "api_key" => true }
  end

  # If a custom secret and/or algorithm is provided, validate against those
  # directly rather than this process's env-resolved defaults.
  if secret || algorithm
    payload = hmac_decode(token, secret || hmac_secret, algorithm: algorithm)
    return payload ? payload : nil
  end

  valid_token(token) ? get_payload(token) : nil
end

.base64url_decode(str) ⇒ Object

Base64url-decode (handles missing padding)



124
125
126
127
128
129
 
# File 'lib/tina4/auth.rb', line 124

def base64url_decode(str)
  # Add back padding
  remainder = str.length % 4
  str += "=" * ((4 - remainder) % 4) if remainder != 0
  Base64.urlsafe_decode64(str)
end

.base64url_encode(data) ⇒ Object

Base64url-encode without padding (JWT spec)



119
120
121
 
# File 'lib/tina4/auth.rb', line 119

def base64url_encode(data)
  Base64.urlsafe_encode64(data, padding: false)
end

.bearer_auth ⇒ Object 



388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
 
# File 'lib/tina4/auth.rb', line 388

def bearer_auth
  lambda do |env|
    auth_header = env["HTTP_AUTHORIZATION"] || ""
    return false unless auth_header =~ /\ABearer\s+(.+)\z/i

    token = Regexp.last_match(1)

    # API_KEY bypass — timing-safe comparison via validate_api_key
    # (OpenSSL.fixed_length_secure_compare). Parity with Python's
    # authenticate_request (validate_api_key), PHP (hash_equals) and
    # Node (timingSafeEqual). Never use a plain `==` here — that leaks the
    # key length/prefix through comparison timing.
    if validate_api_key(token)
      env["tina4.auth"] = { "api_key" => true }
      return true
    end

    if valid_token(token)
      env["tina4.auth"] = get_payload(token)
      true
    else
      false
    end
  end
end

.check_password(password, hash) ⇒ Object 



300
301
302
303
304
305
306
307
308
309
310
311
312
 
# File 'lib/tina4/auth.rb', line 300

def check_password(password, hash)
  parts = hash.split('$')
  return false unless parts.length == 4 && parts[0] == 'pbkdf2_sha256'
  iterations = parts[1].to_i
  salt = parts[2]
  expected = parts[3]
  dk = OpenSSL::KDF.pbkdf2_hmac(password, salt: salt, iterations: iterations, length: 32, hash: "sha256")
  actual = dk.unpack1('H*')
  # Timing-safe comparison
  OpenSSL.fixed_length_secure_compare(actual, expected)
rescue
  false
end

.default_secure_auth ⇒ Object

Default auth handler for secured routes (POST/PUT/PATCH/DELETE) Used automatically unless auth: false is passed



416
417
418
 
# File 'lib/tina4/auth.rb', line 416

def default_secure_auth
  @default_secure_auth ||= bearer_auth
end

.ensure_dev_secret(root_dir = Dir.pwd) ⇒ Object

Boot-time bootstrap (run once after env load, before auth is used).

Mirrors the Python master's tina4_python.auth.ensure_dev_secret:

- If TINA4_SECRET is already set → no-op (returns nil).
- Else if NOT dev, OR CI, OR production → emit the actionable
blank-secret warning and return nil. NEVER generates or persists a
secret in CI or production. (Hard security constraint.)
- Else (dev, not CI, not prod, blank secret) → mint a 32-byte
(64 hex char) random secret, set it in the process env immediately,
then APPEND it to <root_dir>/.env.local (gitignored, created if
missing). On ANY write failure keep the in-memory secret and warn —
never raise (boot must not crash).

root_dir exists only so tests can target a temp dir without chdir; production callers pass nothing (defaults to Dir.pwd).

Returns the generated secret (String) when it mints one, else nil.



65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
 
# File 'lib/tina4/auth.rb', line 65

def ensure_dev_secret(root_dir = Dir.pwd)
  existing = ENV["TINA4_SECRET"]
  return nil if existing && !existing.empty?

  unless dev? && !ci? && !production?
    warn_blank_secret
    return nil
  end

  new_secret = SecureRandom.hex(32) # 32 bytes -> 64 hex chars
  ENV["TINA4_SECRET"] = new_secret  # available for this run immediately

  begin
    local_path = File.join(root_dir, ".env.local")
    # If the file exists and does not end in a newline, prepend one so the
    # new key lands on its own line rather than gluing onto the last value.
    prefix = ""
    if File.exist?(local_path)
      content = File.read(local_path)
      prefix = "\n" if !content.empty? && !content.end_with?("\n")
    end
    File.open(local_path, "a") { |f| f.write("#{prefix}TINA4_SECRET=#{new_secret}\n") }
    log_info("Auth: generated a development secret, saved to .env.local (gitignored)")
  rescue StandardError => e
    # Keep the in-memory secret for this run; just warn. Never crash boot.
    log_warning("Auth: generated a development secret but could not write .env.local (#{e.message}); using it for this run only")
  end

  new_secret
end

.get_payload(token) ⇒ Object 



315
316
317
318
319
320
321
322
323
 
# File 'lib/tina4/auth.rb', line 315

def get_payload(token)
  parts = token.split(".")
  return nil unless parts.length == 3

  payload_json = base64url_decode(parts[1])
  JSON.parse(payload_json)
rescue ArgumentError, JSON::ParserError
  nil
end

.get_token(payload, expires_in: 60, secret: nil, algorithm: nil) ⇒ Object Also known as: create_token

Mint a signed JWT.

algorithm: selects the HMAC algorithm (else TINA4_JWT_ALGORITHM, else HS256); an unsupported one raises ArgumentError rather than quietly downgrading. It applies to the HMAC path only — the legacy RS256 path (RSA keys present in .keys/) is unaffected.

BREAKING (deliberate): no "nbf" claim is stamped. It duplicated "iat", added no security, and created clock-skew rejections; RFC 7519 nbf is for deliberately post-dated tokens, which stays fully supported when the caller passes its own "nbf" in the payload. Python/PHP/Node never auto-stamped it, so Ruby doing so was the parity break.



234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
 
# File 'lib/tina4/auth.rb', line 234

def get_token(payload, expires_in: 60, secret: nil, algorithm: nil)
  now = Time.now.to_i
  claims = payload.merge(
    "iat" => now,
    "exp" => now + (expires_in * 60).to_i
  )

  if secret
    hmac_encode(claims, secret, algorithm: algorithm)
  elsif use_hmac?
    hmac_encode(claims, hmac_secret, algorithm: algorithm)
  else
    ensure_keys
    require "jwt"
    JWT.encode(claims, private_key, "RS256")
  end
end

.hash_password(password, salt = nil, iterations = 260000) ⇒ Object 



294
295
296
297
298
 
# File 'lib/tina4/auth.rb', line 294

def hash_password(password, salt = nil, iterations = 260000)
  salt ||= SecureRandom.hex(16)
  dk = OpenSSL::KDF.pbkdf2_hmac(password, salt: salt, iterations: iterations, length: 32, hash: "sha256")
  "pbkdf2_sha256$#{iterations}$#{salt}$#{dk.unpack1('H*')}"
end

.hmac_decode(token, secret, algorithm: nil) ⇒ Object

Decode and verify an HMAC-signed JWT. Returns the payload hash or nil.

The algorithm is PINNED to our configured one rather than trusted from the token: a header asking to be verified as anything else — "none", a different HMAC, or an RSA alg we do not implement here — is rejected before any signature work.



179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
 
# File 'lib/tina4/auth.rb', line 179

def hmac_decode(token, secret, algorithm: nil)
  # Resolved OUTSIDE the rescue below: an unsupported algorithm is a
  # configuration error that must surface, not become a nil "invalid token".
  alg = resolve_algorithm(algorithm)

  begin
    parts = token.split(".")
    return nil unless parts.length == 3

    header_json = base64url_decode(parts[0])
    header = JSON.parse(header_json)
    return nil unless header["alg"] == alg

    # Verify signature
    signing_input = "#{parts[0]}.#{parts[1]}"
    expected_sig = hmac_signature(alg, secret, signing_input)
    actual_sig = base64url_decode(parts[2])

    # Constant-time comparison to prevent timing attacks. Lengths must match
    # first — fixed_length_secure_compare raises on a length mismatch, which
    # a forged signature of the wrong digest size would trigger.
    return nil unless expected_sig.bytesize == actual_sig.bytesize
    return nil unless OpenSSL.fixed_length_secure_compare(expected_sig, actual_sig)

    payload = JSON.parse(base64url_decode(parts[1]))

    # Check expiry
    now = Time.now.to_i
    return nil if payload["exp"] && now >= payload["exp"]

    # "nbf" (not-before): a post-dated token is not valid yet. Tolerate
    # JWT_LEEWAY_SECONDS of clock skew so a token minted on a host a second
    # ahead is not rejected for nothing.
    return nil if payload["nbf"] && now + JWT_LEEWAY_SECONDS < payload["nbf"]

    payload
  rescue ArgumentError, JSON::ParserError, OpenSSL::HMACError
    nil
  end
end

.hmac_encode(claims, secret, algorithm: nil) ⇒ Object

Build a JWT with Ruby's OpenSSL::HMAC (no gem needed). The algorithm is the explicit argument, else TINA4_JWT_ALGORITHM, else HS256 — and the header advertises exactly the algorithm that signed.



161
162
163
164
165
166
167
168
169
170
171
 
# File 'lib/tina4/auth.rb', line 161

def hmac_encode(claims, secret, algorithm: nil)
  alg = resolve_algorithm(algorithm)
  header = { "alg" => alg, "typ" => "JWT" }
  segments = [
    base64url_encode(JSON.generate(header)),
    base64url_encode(JSON.generate(claims))
  ]
  signing_input = segments.join(".")
  segments << base64url_encode(hmac_signature(alg, secret, signing_input))
  segments.join(".")
end

.hmac_secret ⇒ Object

Lazy per-call secret resolver. When the secret is blank, emit the actionable blank-secret warning (the same text the CI/prod bootstrap path uses) before returning. Parity with Python's _resolve_secret.



112
113
114
115
116
 
# File 'lib/tina4/auth.rb', line 112

def hmac_secret
  secret = ENV["TINA4_SECRET"]
  warn_blank_secret if secret.nil? || secret.empty?
  secret
end

.hmac_signature(algorithm, secret, signing_input) ⇒ Object

HMAC the signing input with the digest the algorithm actually names, so the header's "alg" can never disagree with the bytes we produced.



154
155
156
 
# File 'lib/tina4/auth.rb', line 154

def hmac_signature(algorithm, secret, signing_input)
  OpenSSL::HMAC.digest(HMAC_ALGORITHMS.fetch(algorithm).new, secret.to_s, signing_input)
end

.private_key ⇒ Object 



424
425
426
 
# File 'lib/tina4/auth.rb', line 424

def private_key
  @private_key ||= OpenSSL::PKey::RSA.new(File.read(private_key_path))
end

.public_key ⇒ Object 



428
429
430
 
# File 'lib/tina4/auth.rb', line 428

def public_key
  @public_key ||= OpenSSL::PKey::RSA.new(File.read(public_key_path))
end

.refresh_token(token, expires_in: 60) ⇒ Object

Validate and re-issue a token with the same claims.

Only "iat"/"exp" are dropped (they are re-stamped). A caller-supplied "nbf" is PRESERVED — matching the Python master, and keeping the promise made when auto-nbf was removed: a deliberately post-dated claim is the issuer's, and a refresh must not quietly erase it.



331
332
333
334
335
336
337
338
 
# File 'lib/tina4/auth.rb', line 331

def refresh_token(token, expires_in: 60)
  return nil unless valid_token(token)

  payload = get_payload(token)
  return nil unless payload
  payload = payload.reject { |k, _| %w[iat exp].include?(k) }
  get_token(payload, expires_in: expires_in)
end

.resolve_algorithm(algorithm = nil) ⇒ Object

Pick the JWT algorithm: explicit argument, else TINA4_JWT_ALGORITHM, else HS256. A blank value counts as unset (parity with Python, where an empty env string is falsy and falls through).

Raises ArgumentError naming the supported set when asked for one we cannot sign — Ruby's idiomatic equivalent of the master's ValueError. The env var was registered in the CLI's known_vars and then silently ignored here, so a user could set HS512 and still get HS256 tokens.



139
140
141
142
143
144
145
146
147
148
149
150
 
# File 'lib/tina4/auth.rb', line 139

def resolve_algorithm(algorithm = nil)
  candidate = [algorithm, ENV["TINA4_JWT_ALGORITHM"]]
              .find { |value| !value.nil? && !value.to_s.strip.empty? }
  chosen = (candidate || "HS256").to_s.strip
  unless HMAC_ALGORITHMS.key?(chosen)
    raise ArgumentError,
          "Unsupported JWT algorithm #{chosen.inspect}. Tina4 signs with " \
          "#{HMAC_ALGORITHMS.keys.sort.join(', ')} (HMAC only, zero-dependency). " \
          "Set TINA4_JWT_ALGORITHM to one of those."
  end
  chosen
end

.setup(root_dir = Dir.pwd) ⇒ Object 



42
43
44
45
46
 
# File 'lib/tina4/auth.rb', line 42

def setup(root_dir = Dir.pwd)
  @keys_dir = File.join(root_dir, KEYS_DIR)
  FileUtils.mkdir_p(@keys_dir)
  ensure_keys
end

.use_hmac? ⇒ Boolean

Returns true when SECRET env var is set and no RSA keys exist in .keys/

Returns:

  • (Boolean) 


99
100
101
102
103
104
105
106
107
 
# File 'lib/tina4/auth.rb', line 99

def use_hmac?
  secret = ENV["TINA4_SECRET"]
  return false if secret.nil? || secret.empty?

  # If RSA keys already exist on disk, prefer RS256 for backward compat
  @keys_dir ||= File.join(Dir.pwd, KEYS_DIR)
  !(File.exist?(File.join(@keys_dir, "private.pem")) &&
    File.exist?(File.join(@keys_dir, "public.pem")))
end

.valid_token(token) ⇒ Object

Verify a JWT signature + expiry.

3.13.0: return type changed from Boolean to Hash | nil. The decoded payload is returned on success, nil on failure. Matches firebase/jwt-ruby and Python's Auth.valid_token in 3.13.0.

Legacy if Tina4::Auth.valid_token(t) patterns keep working because a non-empty Hash is truthy and nil is falsy.



261
262
263
264
265
266
267
268
269
270
271
272
 
# File 'lib/tina4/auth.rb', line 261

def valid_token(token)
  if use_hmac?
    hmac_decode(token, hmac_secret) # returns Hash payload or nil
  else
    ensure_keys
    require "jwt"
    decoded = JWT.decode(token, public_key, true, algorithm: "RS256")
    decoded[0] # firebase/jwt-ruby returns [payload, header]
  end
rescue JWT::ExpiredSignature, JWT::DecodeError
  nil
end

.valid_token_detail(token) ⇒ Object Also known as: validate_token 



274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
 
# File 'lib/tina4/auth.rb', line 274

def valid_token_detail(token)
  if use_hmac?
    payload = hmac_decode(token, hmac_secret)
    if payload
      { valid: true, payload: payload }
    else
      { valid: false, error: "Invalid or expired token" }
    end
  else
    ensure_keys
    require "jwt"
    decoded = JWT.decode(token, public_key, true, algorithm: "RS256")
    { valid: true, payload: decoded[0] }
  end
rescue JWT::ExpiredSignature
  { valid: false, error: "Token expired" }
rescue JWT::DecodeError => e
  { valid: false, error: e.message }
end

.validate_api_key(provided, expected: nil) ⇒ Object 



371
372
373
374
375
376
377
378
 
# File 'lib/tina4/auth.rb', line 371

def validate_api_key(provided, expected: nil)
  expected ||= ENV["TINA4_API_KEY"]
  return false if expected.nil? || expected.empty?
  return false if provided.nil? || provided.empty?
  return false if provided.length != expected.length

  OpenSSL.fixed_length_secure_compare(provided, expected)
end