Autentikasi SCRAM-SHA-256 (RFC 5802/7677), terverifikasi vektor uji

Author: taqiin

README.md

@@ -39,14 +39,16 @@ kalau db < 0 {
 
 ## Autentikasi
 
-Didukung: `trust` (tanpa sandi), `cleartext`, `md5`. SCRAM-SHA-256 belum (memerlukan primitif kripto tambahan) — gunakan `md5`/`trust` di `pg_hba.conf` untuk sementara.
+Didukung: `trust`, `cleartext`, `md5`, dan **`scram-sha-256`** (default PostgreSQL modern). Implementasi SCRAM (RFC 5802/7677) memakai builtin kripto `pbkdf2`/`hmacSha256Raw`/`sha256Raw`/`xor`/`base64` — ClientProof terverifikasi terhadap vektor uji RFC 7677.
 
 ## Struktur
 
 ```
 modul-postgres/
   tenun.json
-  src/postgres.tenun
+  src/
+    postgres.tenun    koneksi, query (sederhana & berparameter), parser
+    scram.tenun       autentikasi SCRAM-SHA-256
   contoh/contoh.tenun
   .github/workflows/ci.yml
 ```

src/postgres.tenun

@@ -2,6 +2,8 @@
 // Auth: trust (0), cleartext (3), md5 (5). SCRAM (10) belum didukung.
 // Dibangun di atas builtin inti: sambung/kirim/terimaPasti, keByte/bacaInt, md5, potong.
 
+impor "./scram.tenun";
+
 // Baca satu pesan: type(1) + panjang(4, big-endian) + body. Kembalikan pesan utuh.
 fungsi pg_baca(s: bulat): teks {
     biar hdr: teks = terimaPasti(s, 5);
@@ -43,9 +45,13 @@ fungsi pg_sambung(inang: teks, port: bulat, pengguna: teks, sandi: teks, db: tek
                 biar tok: teks = "md5" + md5(inner + salt) + nul;
                 kirim(s, pg_pesan(112, tok));
             }
-            kalau at == 10 {          // SASL/SCRAM — belum didukung
-                kembali -1;
+            kalau at == 10 {          // SASL: mulai SCRAM-SHA-256
+                pg_scram_mulai(s);
+            }
+            kalau at == 11 {          // SASLContinue: server-first
+                pg_scram_lanjut(s, sandi, potong(m, 9, panjangTeks(m) - 9));
             }
+            // at == 12 (SASLFinal) diabaikan; lanjut ke AuthenticationOk + ReadyForQuery
         }
     }
     kembali s;

src/scram.tenun

@@ -0,0 +1,43 @@
+// SCRAM-SHA-256 (RFC 5802 / 7677) untuk autentikasi PostgreSQL.
+// Memakai builtin kripto: pbkdf2, hmacSha256Raw, sha256Raw, xor, base64, dariBase64, acak.
+
+biar pg_nonce: teks = "";
+biar pg_cfirst_bare: teks = "";
+
+// ClientProof (base64) dari sandi, salt mentah, iterasi, dan AuthMessage.
+fungsi pg_scram_proof(sandi: teks, salt: teks, iter: bulat, authMessage: teks): teks {
+    biar sp: teks = pbkdf2(sandi, salt, iter);          // SaltedPassword
+    biar ck: teks = hmacSha256Raw(sp, "Client Key");     // ClientKey
+    biar sk: teks = sha256Raw(ck);                        // StoredKey
+    biar cs: teks = hmacSha256Raw(sk, authMessage);      // ClientSignature
+    kembali base64(xor(ck, cs));                          // ClientProof
+}
+
+// Langkah 1: kirim SASLInitialResponse (client-first).
+fungsi pg_scram_mulai(s: bulat): kosong {
+    pg_nonce = acak(18);
+    pg_cfirst_bare = "n=,r=" + pg_nonce;
+    biar cfirst: teks = "n,," + pg_cfirst_bare;
+    biar nul: teks = keByte(0, 1, salah);
+    biar body: teks = "SCRAM-SHA-256" + nul + keByte(panjangTeks(cfirst), 4, benar) + cfirst;
+    kirim(s, pg_pesan(112, body));   // 'p'
+}
+
+// Langkah 2: terima server-first, hitung proof, kirim client-final.
+fungsi pg_scram_lanjut(s: bulat, sandi: teks, serverFirst: teks): kosong {
+    biar bagian: []teks = pisah(serverFirst, ",");
+    biar rnonce: teks = "";
+    biar saltB64: teks = "";
+    biar iter: bulat = 4096;
+    untuk i dari 0 sampai panjang(bagian) {
+        biar f: teks = bagian[i];
+        kalau mulaiDengan(f, "r=") { rnonce = potong(f, 2, panjangTeks(f) - 2); }
+        kalau mulaiDengan(f, "s=") { saltB64 = potong(f, 2, panjangTeks(f) - 2); }
+        kalau mulaiDengan(f, "i=") { iter = keBulat(potong(f, 2, panjangTeks(f) - 2)); }
+    }
+    biar salt: teks = dariBase64(saltB64);
+    biar cfinal_np: teks = "c=biws,r=" + rnonce;
+    biar authMessage: teks = pg_cfirst_bare + "," + serverFirst + "," + cfinal_np;
+    biar proof: teks = pg_scram_proof(sandi, salt, iter, authMessage);
+    kirim(s, pg_pesan(112, cfinal_np + ",p=" + proof));   // 'p'
+}