tls: support TLS min/max protocol defaults in CLI

Backport CLI switches for default TLS versions:
- `--tls-max-v1.2`
- `--tls-min-v1.0`
- `--tls-min-v1.1`
- `--tls-min-v1.2`

PR-URL: #27946
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>

Author: sam-github

Diff for: doc/api/cli.md

@@ -359,6 +359,38 @@ added: v4.0.0
 Specify an alternative default TLS cipher list. Requires Node.js to be built
 with crypto support (default).
 
+### `--tls-max-v1.2`
+<!-- YAML
+added: REPLACEME
+-->
+
+Does nothing, [`tls.DEFAULT_MAX_VERSION`][] is always 'TLSv1.2'. Exists for
+compatibility with Node.js 11.x and higher.
+
+### `--tls-min-v1.0`
+<!-- YAML
+added: REPLACEME
+-->
+
+Set default [`tls.DEFAULT_MIN_VERSION`][] to 'TLSv1'. Use for compatibility with
+old TLS clients or servers.
+
+### `--tls-min-v1.1`
+<!-- YAML
+added: REPLACEME
+-->
+
+Set default [`tls.DEFAULT_MIN_VERSION`][] to 'TLSv1.1'. Use for compatibility
+with old TLS clients or servers.
+
+### `--tls-min-v1.2`
+<!-- YAML
+added: REPLACEME
+-->
+
+Set default [`tls.DEFAULT_MIN_VERSION`][] to 'TLSv1.2'. Use this to disable
+support for earlier TLS versions, which are less secure.
+
 ### `--trace-deprecation`
 <!-- YAML
 added: v0.8.0

Diff for: doc/api/tls.md

@@ -1378,7 +1378,11 @@ added: v10.6.0
 * {string} The default value of the `minVersion` option of
   [`tls.createSecureContext()`][]. It can be assigned any of the supported TLS
   protocol versions, `TLSv1.2'`, `'TLSv1.1'`, or `'TLSv1'`.
-  **Default:** `'TLSv1'`.
+  **Default:** `'TLSv1'`, unless changed using CLI options. Using
+  `--tls-min-v1.0` sets the default to `'TLSv1'`. Using `--tls-min-v1.1` sets
+  the default to `'TLSv1.1'`. Using `--tls-min-v1.2` sets the default to
+  `'TLSv1.2'`. If multiple of the options are provided, the lowest minimum is
+  used.
 
 ## Deprecated APIs
 

Diff for: doc/node.1

@@ -198,6 +198,22 @@ Specify process.title on startup.
 Specify an alternative default TLS cipher list.
 Requires Node.js to be built with crypto support. (Default)
 .
+.It Fl -tls-max-v1.2
+Does nothing, the default  maxVersion is always 'TLSv1.2'. Exists for
+compatibility with Node.js 11.x and higher.
+.
+.It Fl -tls-min-v1.0
+Set default minVersion to 'TLSv1'. Use for compatibility with old TLS clients
+or servers.
+.
+.It Fl -tls-min-v1.1
+Set default minVersion to 'TLSv1.1'. Use for compatibility with old TLS clients
+or servers.
+.
+.It Fl -tls-min-v1.2
+Set default minVersion to 'TLSv1.2'. Use to disable support for earlier TLS
+versions, which are less secure.
+.
 .It Fl -trace-deprecation
 Print stack traces for deprecations.
 .

Diff for: lib/tls.js

@@ -31,6 +31,7 @@ internalUtil.assertCrypto();
 const { isUint8Array } = require('internal/util/types');
 
 const net = require('net');
+const { getOptionValue } = require('internal/options');
 const url = require('url');
 const binding = internalBinding('crypto');
 const { Buffer } = require('buffer');
@@ -52,9 +53,19 @@ exports.DEFAULT_CIPHERS =
 
 exports.DEFAULT_ECDH_CURVE = 'auto';
 
-exports.DEFAULT_MAX_VERSION = 'TLSv1.2';
-
-exports.DEFAULT_MIN_VERSION = 'TLSv1';
+if (getOptionValue('--tls-min-v1.0'))
+  exports.DEFAULT_MIN_VERSION = 'TLSv1';
+else if (getOptionValue('--tls-min-v1.1'))
+  exports.DEFAULT_MIN_VERSION = 'TLSv1.1';
+else if (getOptionValue('--tls-min-v1.2'))
+  exports.DEFAULT_MIN_VERSION = 'TLSv1.2';
+else
+  exports.DEFAULT_MIN_VERSION = 'TLSv1';
+
+if (getOptionValue('--tls-max-v1.2'))
+  exports.DEFAULT_MAX_VERSION = 'TLSv1.2';
+else
+  exports.DEFAULT_MAX_VERSION = 'TLSv1.2'; // Will depend on node version.
 
 exports.getCiphers = internalUtil.cachedResult(
   () => internalUtil.filterDuplicateStrings(binding.getSSLCiphers(), true)

Diff for: src/node_options.cc

@@ -210,6 +210,23 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
 
   Insert(&DebugOptionsParser::instance,
          &EnvironmentOptions::get_debug_options);
+
+  AddOption("--tls-min-v1.0",
+            "set default TLS minimum to TLSv1.0 (default: TLSv1.0)",
+            &EnvironmentOptions::tls_min_v1_0,
+            kAllowedInEnvironment);
+  AddOption("--tls-min-v1.1",
+            "set default TLS minimum to TLSv1.1 (default: TLSv1.0)",
+            &EnvironmentOptions::tls_min_v1_1,
+            kAllowedInEnvironment);
+  AddOption("--tls-min-v1.2",
+            "set default TLS minimum to TLSv1.2 (default: TLSv1.0)",
+            &EnvironmentOptions::tls_min_v1_2,
+            kAllowedInEnvironment);
+  AddOption("--tls-max-v1.2",
+            "set default TLS maximum to TLSv1.2 (default: TLSv1.2)",
+            &EnvironmentOptions::tls_max_v1_2,
+            kAllowedInEnvironment);
 }
 
 EnvironmentOptionsParser EnvironmentOptionsParser::instance;

Diff for: src/node_options.h

@@ -94,6 +94,10 @@ class EnvironmentOptions : public Options {
   bool force_repl = false;
 
   bool insecure_http_parser = false;
+  bool tls_min_v1_0 = false;
+  bool tls_min_v1_1 = false;
+  bool tls_min_v1_2 = false;
+  bool tls_max_v1_2 = false;
 
   std::vector<std::string> preload_modules;
 

Diff for: test/parallel/test-process-env-allowed-flags.js

@@ -51,7 +51,7 @@ require('../common');
 // assert all "canonical" flags begin with dash(es)
 {
   process.allowedNodeEnvironmentFlags.forEach((flag) => {
-    assert(/^--?[a-z28_-]+$/.test(flag), `Unexpected format for flag ${flag}`);
+    assert(/^--?[a-z.0-9_-]+$/.test(flag), `Unexpected format for flag ${flag}`);
   });
 }
 

Diff for: test/parallel/test-tls-cli-max-version-1.2.js

@@ -0,0 +1,15 @@
+// Flags: --tls-max-v1.2
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto) common.skip('missing crypto');
+
+// Check that node `--tls-max-v1.2` is supported.
+
+const assert = require('assert');
+const tls = require('tls');
+
+assert.strictEqual(tls.DEFAULT_MAX_VERSION, 'TLSv1.2');
+assert.strictEqual(tls.DEFAULT_MIN_VERSION, 'TLSv1');
+
+// Check the min-max version protocol versions against these CLI settings.
+require('./test-tls-min-max-version.js');

Diff for: test/parallel/test-tls-cli-min-version-1.0.js

@@ -0,0 +1,15 @@
+// Flags: --tls-min-v1.0 --tls-min-v1.1
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto) common.skip('missing crypto');
+
+// Check that `node --tls-v1.0` is supported, and overrides --tls-v1.1.
+
+const assert = require('assert');
+const tls = require('tls');
+
+assert.strictEqual(tls.DEFAULT_MAX_VERSION, 'TLSv1.2');
+assert.strictEqual(tls.DEFAULT_MIN_VERSION, 'TLSv1');
+
+// Check the min-max version protocol versions against these CLI settings.
+require('./test-tls-min-max-version.js');

Diff for: test/parallel/test-tls-cli-min-version-1.1.js

@@ -0,0 +1,15 @@
+// Flags: --tls-min-v1.1
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto) common.skip('missing crypto');
+
+// Check that node `--tls-v1.1` is supported.
+
+const assert = require('assert');
+const tls = require('tls');
+
+assert.strictEqual(tls.DEFAULT_MAX_VERSION, 'TLSv1.2');
+assert.strictEqual(tls.DEFAULT_MIN_VERSION, 'TLSv1.1');
+
+// Check the min-max version protocol versions against these CLI settings.
+require('./test-tls-min-max-version.js');

Diff for: test/parallel/test-tls-cli-min-version-1.2.js

@@ -0,0 +1,15 @@
+// Flags: --tls-min-v1.2
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto) common.skip('missing crypto');
+
+// Check that node `--tls-min-v1.2` is supported.
+
+const assert = require('assert');
+const tls = require('tls');
+
+assert.strictEqual(tls.DEFAULT_MAX_VERSION, 'TLSv1.2');
+assert.strictEqual(tls.DEFAULT_MIN_VERSION, 'TLSv1.2');
+
+// Check the min-max version protocol versions against these CLI settings.
+require('./test-tls-min-max-version.js');

Diff for: test/parallel/test-tls-min-max-version.js

@@ -10,11 +10,12 @@ const {
 const DEFAULT_MIN_VERSION = tls.DEFAULT_MIN_VERSION;
 const DEFAULT_MAX_VERSION = tls.DEFAULT_MAX_VERSION;
 
-// For v11.x, the default is fixed and cannot be changed via CLI.
-assert.strictEqual(DEFAULT_MIN_VERSION, 'TLSv1');
-
 function test(cmin, cmax, cprot, smin, smax, sprot, proto, cerr, serr) {
   assert(proto || cerr || serr, 'test missing any expectations');
+  // Report where test was called from. Strip leading garbage from
+  //     at Object.<anonymous> (file:line)
+  // from the stack location, we only want the file:line part.
+  const where = (new Error()).stack.split('\n')[2].replace(/[^(]*/, '');
   connect({
     client: {
       checkServerIdentity: (servername, cert) => { },
@@ -34,9 +35,28 @@ function test(cmin, cmax, cprot, smin, smax, sprot, proto, cerr, serr) {
     function u(_) { return _ === undefined ? 'U' : _; }
     console.log('test:', u(cmin), u(cmax), u(cprot), u(smin), u(smax), u(sprot),
                 'expect', u(proto), u(cerr), u(serr));
+    console.log('   ', where);
     if (!proto) {
-      console.log('client', pair.client.err ? pair.client.err.code : undefined);
-      console.log('server', pair.server.err ? pair.server.err.code : undefined);
+      function setCode(err) {
+        if (!err) return;
+        if (err.code) return;
+        // Convert error message to a .code, because .code wasn't always present
+        // in older versions.
+        if (/unsupported protocol/.test(err.message))
+          err.code = 'ERR_SSL_UNSUPPORTED_PROTOCOL';
+        else if (/wrong version number/.test(err.message))
+          err.code = 'ERR_SSL_WRONG_VERSION_NUMBER';
+        else if (/version too low/.test(err.message))
+          err.code = 'ERR_SSL_UNSUPPORTED_PROTOCOL';
+        else
+          err.code = err.message;
+      }
+      setCode(pair.server.err);
+      setCode(pair.client.err);
+      console.log('client', pair.client.err ? pair.client.err.code :
+        pair.client.err);
+      console.log('server', pair.server.err ? pair.server.err.code :
+        pair.server.err);
       // 11.x doesn't have https://github.com/nodejs/node/pull/24729
       if (cerr === 'ERR_TLS_INVALID_PROTOCOL_METHOD' &&
           pair.client.err &&