default to SHA2-512 for RSA signature

README.md

@@ -31,6 +31,7 @@ A seed is used to generate the secret, it's recommended you don't use the same s
 ## ⚠️ Limitations
 
 - Can't use ECDSA keys, they always give different signatures
+- [RFC8332](https://www.rfc-editor.org/info/rfc8332) compatible agent (e.g. OpenSSH 7.6+) mandatory to use SHA2-512 signature scheme. You can still use deprecated SHA1 signatures with `rsaSignatureFlag: 0` option in `SSHAgentClient` constructor.
 
 ## 💻 CLI usage
 
@@ -93,3 +94,10 @@ const decrypted = await agent.decrypt(
 )
 console.log('Decrypted data:', decrypted.toString('utf8'))
 ```
+
+## Local test
+
+```bash
+ssh-agent -D
+SSH_AUTH_SOCK= ssh-add id_ecdsa id_ed25519 id_rsa
+```

src/lib/ssh_agent_client.ts

@@ -15,6 +15,14 @@ const Protocol = {
 
 type Protocol = (typeof Protocol)[keyof typeof Protocol]
 
+export const RsaSignatureFlag = {
+  DEFAULT: 0,
+  SSH_AGENT_RSA_SHA2_256: 2,
+  SSH_AGENT_RSA_SHA2_512: 4,
+} as const
+
+type RsaSignatureFlag = (typeof RsaSignatureFlag)[keyof typeof RsaSignatureFlag]
+
 export interface SSHKey {
   /** E.g. "ssh-rsa" */
   type: string
@@ -40,6 +48,8 @@ export interface SSHAgentClientOptions {
   sockFile?: string
   cipherAlgo?: string
   digestAlgo?: string
+  /** RSA signature method flag for signing request when using RSA keys */
+  rsaSignatureFlag?: RsaSignatureFlag
 }
 
 /** Read a length-prefixed string (uint32 BE length + bytes) from a buffer. */
@@ -71,6 +81,7 @@ export class SSHAgentClient {
   private readonly sockFile: string
   private readonly cipherAlgo: string
   private readonly digestAlgo: string
+  private readonly rsaSignatureFlag: RsaSignatureFlag
 
   /**
    * @param options - Optional configuration.
@@ -84,6 +95,8 @@ export class SSHAgentClient {
     this.cipherAlgo = options.cipherAlgo ?? 'aes-256-cbc'
     this.digestAlgo = options.digestAlgo ?? 'sha256'
 
+    this.rsaSignatureFlag = options.rsaSignatureFlag ?? RsaSignatureFlag.SSH_AGENT_RSA_SHA2_512
+
     const sockFile = options.sockFile ?? process.env.SSH_AUTH_SOCK
     if (!sockFile || !existsSync(sockFile)) {
       throw new Error(`Socket ${sockFile ?? '?'} not found`)
@@ -161,7 +174,7 @@ export class SSHAgentClient {
       let offset = writeHeader(req, Protocol.SSH2_AGENTC_SIGN_REQUEST)
       offset = writeString(req, key.raw, offset)
       offset = writeString(req, data, offset)
-      req.writeUInt32BE(0, offset) // Flags = 0
+      req.writeUInt32BE(this.rsaSignatureFlag, offset)
       return req
     }
 

test/ssh_agent_cli.spec.ts

@@ -42,9 +42,9 @@ describe('ssh-crypt cli tests', () => {
   })
   it('should decrypt', () => {
     const data =
-      'ecfd6bb57f4891ba7226886e90d2eb848022a495b15ffd91ffe760bca5605f9062c305ee14226d9daf7faa58460c8f50'
+      '5f1979820d75926171e7028d5938f64ba5872683334f21b14947df1a4cce1f9ff1bb7c9c91e28e49aa8807b02c18c48c'
     const output = execSync(
-      'npm exec -- tsx src/cli.ts -k key_rsa -s not_a_secret --decryptEncoding hex decrypt',
+      'npm exec -- tsx src/cli.ts -k key_ed25519 -s not_a_secret --decryptEncoding hex decrypt',
       {
         encoding: 'utf8',
         input: data,

test/ssh_agent_client.spec.ts

@@ -1,7 +1,7 @@
 import * as chai from 'chai'
 import { describe, it } from 'mocha'
+import { RsaSignatureFlag, SSHAgentClient } from '../src/lib/ssh_agent_client.ts'
 import chaiAsPromised from 'chai-as-promised'
-import { SSHAgentClient } from '../src/lib/ssh_agent_client.ts'
 
 chai.use(chaiAsPromised)
 
@@ -65,8 +65,8 @@ describe('SSHAgentClient tests', () => {
     chai.assert.strictEqual(identity.type, 'ssh-rsa')
     chai.assert.strictEqual(identity.comment, 'key_rsa')
   })
-  it('should sign', async () => {
-    const agent = new SSHAgentClient()
+  it('should sign with key_rsa and default ssh-rsa signature', async () => {
+    const agent = new SSHAgentClient({ rsaSignatureFlag: RsaSignatureFlag.DEFAULT })
     const identity = await agent.getIdentity('key_rsa')
     if (!identity) {
       throw new Error()
@@ -78,6 +78,55 @@ describe('SSHAgentClient tests', () => {
       '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',
     )
   })
+  it('should sign with key_rsa and SHA2-256 signature', async () => {
+    const agent = new SSHAgentClient({ rsaSignatureFlag: RsaSignatureFlag.SSH_AGENT_RSA_SHA2_256 })
+    const identity = await agent.getIdentity('key_rsa')
+    if (!identity) {
+      throw new Error()
+    }
+    const signature = await agent.sign(identity, Buffer.from('hello', 'utf8'))
+    chai.assert.strictEqual(signature.type, 'rsa-sha2-256')
+    chai.assert.strictEqual(
+      signature.signature,
+      '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',
+    )
+  })
+  it('should sign with key_rsa and SHA2-512 signature', async () => {
+    const agent = new SSHAgentClient({ rsaSignatureFlag: RsaSignatureFlag.SSH_AGENT_RSA_SHA2_512 })
+    const identity = await agent.getIdentity('key_rsa')
+    if (!identity) {
+      throw new Error()
+    }
+    const signature = await agent.sign(identity, Buffer.from('hello', 'utf8'))
+    chai.assert.strictEqual(signature.type, 'rsa-sha2-512')
+    chai.assert.strictEqual(
+      signature.signature,
+      'PEOu4DK+GXsdgd84PEEAFzQgsSz6kgCGiVgf4d464mBGyXhebFR5HBZ4RPCKDIPAu6zFt7DgAYBDmBio0LdwqgAs561ytLO+pQ1UCS1nmzE8f9n8220vGp18PSIXzDPAwlbAk9tPv940kFWbQOr1GwxmyERWC0XOdMLvueeCx5alThYWOAKbjHLhMSAry9E0I02g44UkoFV0VAgrSff03t9Y31c+n5ogpa2bii02IFg3khycrzaYv+3B+aU9kew7MhFH9awkJLFbFuQbLtOiINwhkZRnTAMbrqZPqeYpKrhHr+D6gjNhYXqNhAfZKBJFUurVAkccmkFWttmAZJwCpoiDD+yrOTYj7s5iQq5M0YlrIv3N+RP7MyN9GhvWwlD/Ti5Mnc7EckAIBIrFAja8hdJqmNbeVKD2o5tqJopvz7vvGpOiUHAZyL9Gbd74W3yjX971rZKSHsKtC7ngi3GqUK64QJ/sLjutQXnsxCWvEPaltnsT8dlyjdi2iizP1Prn',
+    )
+  })
+  it('should sign with ed25519', async () => {
+    const agent = new SSHAgentClient()
+    const identity = await agent.getIdentity('key_ed25519')
+    if (!identity) {
+      throw new Error()
+    }
+    const signature = await agent.sign(identity, Buffer.from('hello', 'utf8'))
+    chai.assert.strictEqual(signature.type, 'ssh-ed25519')
+    chai.assert.strictEqual(
+      signature.signature,
+      'Uolma4H0fzvBSu1G/6pUYZthmFH/NjXRjP4Zx80SloXMIlTFsF/++HqOi4ooEhLoTh/ZlhAlyEONjVqqcAnWAQ==',
+    )
+  })
+  it('can sign with ecdsa', async () => {
+    const agent = new SSHAgentClient()
+    const identity = await agent.getIdentity('key_ecdsa')
+    if (!identity) {
+      throw new Error()
+    }
+    const signature = await agent.sign(identity, Buffer.from('hello', 'utf8'))
+    chai.assert.strictEqual(signature.type, 'ecdsa-sha2-nistp256')
+    // Can't assert signature value as it is not deterministic
+  })
   it('should throw if wrong secret', async () => {
     const agent = new SSHAgentClient()
     const identity = await agent.getIdentity('key_rsa')
@@ -153,13 +202,13 @@ describe('SSHAgentClient cipher combination tests', () => {
     const decrypted = await agent.decrypt(
       identity,
       SEED,
-      'ecfd6bb57f4891ba7226886e90d2eb848022a495b15ffd91ffe760bca5605f9062c305ee14226d9daf7faa58460c8f50',
+      '5af153e6fbf83b40cf98ed8bf5710321aa3234b2121cc3d8c47ef6854007f35ece319b056ddba7791b1db776b26a7ea7',
     )
     chai.assert.strictEqual(decrypted.toString('utf8'), DECODED_STRING)
   })
   it('should encrypt and decrypt with aes128/shake128', async () => {
     const agent = new SSHAgentClient({ cipherAlgo: 'aes-128-cbc', digestAlgo: 'shake128' })
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
@@ -168,13 +217,13 @@ describe('SSHAgentClient cipher combination tests', () => {
     const decrypted = await agent.decrypt(
       identity,
       SEED,
-      '9126f351eb84b1d9316b2808c69a09d379fa9f20d4f4a8d4e30135dbba262cbbfc3ad3774fcade60e6d1ae7c75af0a9c',
+      '9a9bdd5451fd1ed8220f4ce23a17aa0981d69521cadd73ff219fd85aa01bc8a3a44cbe95502854a5b37296e93a91db91',
     )
     chai.assert.strictEqual(decrypted.toString('utf8'), DECODED_STRING)
   })
-  it('should encrypt with non matching aes192/sha512', async () => {
+  it('should encrypt and decrypt with non matching aes192/sha512', async () => {
     const agent = new SSHAgentClient({ cipherAlgo: 'aes-192-cbc', digestAlgo: 'sha512' })
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
@@ -183,7 +232,7 @@ describe('SSHAgentClient cipher combination tests', () => {
     const decrypted = await agent.decrypt(
       identity,
       SEED,
-      '280cd2993bb8f9d7ec14ef0c1d94d4ac8e128a39f3f9cba9f5730a7d99674057766e099c17a6786a4a6b33670d1b45b7',
+      '1e69398e2ad6ab5e1f748d538fafe6e54e9824b0646af6666437c556398a7495b48f76db5df52d52f9adde0a232465ab',
     )
     chai.assert.strictEqual(decrypted.toString('utf8'), DECODED_STRING)
   })
@@ -192,7 +241,7 @@ describe('SSHAgentClient cipher combination tests', () => {
 describe('SSHAgentClient encodings tests', () => {
   it('should encrypt to base64', async () => {
     const agent = new SSHAgentClient()
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
@@ -201,14 +250,14 @@ describe('SSHAgentClient encodings tests', () => {
   })
   it('should decrypt from base64', async () => {
     const agent = new SSHAgentClient()
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
     const decrypted = await agent.decrypt(
       identity,
       SEED,
-      '8epe+B3bWcSGTPpyW2MRqHeAKjTj2NVnR4q1YNVB5LfXw9JE02wsb3RqZBTFbMXc',
+      'QMf1r1/ZONTJImZyY1qO+ibDTqLCZNwD2dMs/tpfVpfLKovb7flyiU1Au/01xffv',
       'base64',
     )
     chai.assert.strictEqual(decrypted.toString('utf8'), DECODED_STRING)

test/ssh_agent_stream.spec.ts

@@ -14,7 +14,7 @@ const SEED = 'not_a_secret'
 describe('SSHAgentClient streams tests', () => {
   it('should encrypt', async () => {
     const agent = new SSHAgentClient()
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
@@ -25,13 +25,13 @@ describe('SSHAgentClient streams tests', () => {
   })
   it('should decrypt', async () => {
     const agent = new SSHAgentClient()
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
     const transform = await agent.getDecryptTransform(identity, SEED, 'hex')
     const stream = Readable.from(
-      'ecfd6bb57f4891ba7226886e90d2eb848022a495b15ffd91ffe760bca5605f9062c305ee14226d9daf7faa58460c8f50',
+      '2e306f1403b72eb17fe7187545dbd863be234ad1128ac3f34d60d102ced7bc43a7c4506d341463cff257b4d007b39143',
     )
     const decrypted = await text(stream.pipe(transform))
     chai.assert.strictEqual(decrypted, DECODED_STRING)
@@ -41,7 +41,7 @@ describe('SSHAgentClient streams tests', () => {
 describe('SSHAgentClient streams encodings tests', () => {
   it('should encrypt to base64', async () => {
     const agent = new SSHAgentClient()
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
@@ -52,12 +52,12 @@ describe('SSHAgentClient streams encodings tests', () => {
   })
   it('should decrypt from base64', async () => {
     const agent = new SSHAgentClient()
-    const identity = await agent.getIdentity('key_rsa')
+    const identity = await agent.getIdentity('key_ed25519')
     if (!identity) {
       throw new Error()
     }
     const transform = await agent.getDecryptTransform(identity, SEED, 'base64')
-    const stream = Readable.from('8epe+B3bWcSGTPpyW2MRqHeAKjTj2NVnR4q1YNVB5LfXw9JE02wsb3RqZBTFbMXc')
+    const stream = Readable.from('5e0UbJX4+Rad+byLPnRNho3Qvjbeeqcwmg7yrXinHrTZ0788uuyvTl9jjbcpErF6')
     const decrypted = await text(stream.pipe(transform))
     chai.assert.strictEqual(decrypted, DECODED_STRING)
   })