[stdlib/pg] add scram-sha-256 auth support

.github/workflows/ci.yml

@@ -200,19 +200,24 @@ jobs:
 
     env:
       PG_TESTS_ENABLED: 1
+      PG_SCRAM_TESTS_ENABLED: 1
       PGPASSWORD: test
 
     steps:
       - uses: actions/checkout@v4
 
-      - name: Force pg password to md5 encryption
+      - name: Force pg password to md5 encryption (primary postgres user)
         # postgres:16 image defaults to password_encryption=scram-sha-256, so
-        # the `postgres` user is scram-hashed. Our pure-TS pg driver implements
-        # md5 auth (SCRAM is follow-up) — re-hash password as md5.
+        # the `postgres` user is scram-hashed by default. Our pure-TS pg driver
+        # implements both md5 AND SCRAM-SHA-256; we re-hash the default user as
+        # md5 so the md5 fixtures exercise that code path, and create a second
+        # `scramuser` (scram-sha-256 hashed) for the SCRAM fixture.
         run: |
           sudo apt-get install -y postgresql-client
           psql -h localhost -p 5432 -U postgres -d chadtest \
             -c "SET password_encryption='md5'; ALTER USER postgres PASSWORD 'test';"
+          psql -h localhost -p 5432 -U postgres -d chadtest \
+            -c "SET password_encryption='scram-sha-256'; CREATE USER scramuser SUPERUSER PASSWORD 'test';"
 
       - uses: dorny/paths-filter@v3
         id: changes
@@ -271,7 +276,7 @@ jobs:
       - name: Verify vendor libraries
         run: |
           fail=0
-          for lib in vendor/bdwgc/libgc.a vendor/yyjson/libyyjson.a vendor/libuv/build/libuv.a vendor/picohttpparser/picohttpparser.o vendor/rure/librure.a c_bridges/lws-bridge.o c_bridges/multipart-bridge.o c_bridges/regex-bridge.o c_bridges/child-process-bridge.o c_bridges/child-process-spawn.o c_bridges/trampoline-bridge.o c_bridges/os-bridge.o c_bridges/strlen-cache.o c_bridges/time-bridge.o c_bridges/base64-bridge.o c_bridges/url-bridge.o c_bridges/uri-bridge.o c_bridges/dotenv-bridge.o c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o; do
+          for lib in vendor/bdwgc/libgc.a vendor/yyjson/libyyjson.a vendor/libuv/build/libuv.a vendor/picohttpparser/picohttpparser.o vendor/rure/librure.a c_bridges/lws-bridge.o c_bridges/multipart-bridge.o c_bridges/regex-bridge.o c_bridges/child-process-bridge.o c_bridges/child-process-spawn.o c_bridges/trampoline-bridge.o c_bridges/os-bridge.o c_bridges/strlen-cache.o c_bridges/time-bridge.o c_bridges/base64-bridge.o c_bridges/url-bridge.o c_bridges/uri-bridge.o c_bridges/dotenv-bridge.o c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/scram-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o; do
             if [ ! -f "$lib" ]; then
               echo "MISSING: $lib"
               fail=1
@@ -338,14 +343,15 @@ jobs:
           cp c_bridges/multipart-bridge.o release/lib/
           cp c_bridges/regex-bridge.o release/lib/
           cp c_bridges/net-bridge.o release/lib/
+          cp c_bridges/scram-bridge.o release/lib/
           cp vendor/rure/librure.a release/lib/
           cp c_bridges/child-process-bridge.o release/lib/
           cp c_bridges/child-process-spawn.o release/lib/
           cp c_bridges/trampoline-bridge.o release/lib/
           cp c_bridges/os-bridge.o c_bridges/strlen-cache.o release/lib/
           cp c_bridges/time-bridge.o c_bridges/base64-bridge.o c_bridges/url-bridge.o c_bridges/uri-bridge.o release/lib/
           cp c_bridges/dotenv-bridge.o release/lib/
-          cp c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o release/lib/
+          cp c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/scram-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o release/lib/
           tar -czf chadscript-linux-x64.tar.gz -C release chad lib
 
       - name: Upload artifact
@@ -365,6 +371,7 @@ jobs:
 
     env:
       PG_TESTS_ENABLED: 1
+      PG_SCRAM_TESTS_ENABLED: 1
 
     steps:
       - uses: actions/checkout@v4
@@ -416,6 +423,7 @@ jobs:
           psql postgres -c "SET password_encryption='md5'; CREATE USER postgres SUPERUSER PASSWORD 'test';" || echo "postgres user already exists"
           psql postgres -c "SET password_encryption='md5'; ALTER USER postgres WITH PASSWORD 'test';"
           psql postgres -c "CREATE DATABASE chadtest OWNER postgres;" || echo "chadtest db already exists"
+          psql postgres -c "SET password_encryption='scram-sha-256'; CREATE USER scramuser SUPERUSER PASSWORD 'test';" || echo "scramuser already exists"
           psql -h localhost -p 5432 -U postgres -d chadtest -c "SELECT 1;" postgresql://postgres:test@localhost:5432/chadtest
 
       - name: Install npm dependencies
@@ -438,7 +446,7 @@ jobs:
       - name: Verify vendor libraries
         run: |
           fail=0
-          for lib in vendor/bdwgc/libgc.a vendor/yyjson/libyyjson.a vendor/libuv/build/libuv.a vendor/picohttpparser/picohttpparser.o vendor/rure/librure.a c_bridges/lws-bridge.o c_bridges/multipart-bridge.o c_bridges/regex-bridge.o c_bridges/child-process-bridge.o c_bridges/child-process-spawn.o c_bridges/trampoline-bridge.o c_bridges/os-bridge.o c_bridges/strlen-cache.o c_bridges/time-bridge.o c_bridges/base64-bridge.o c_bridges/url-bridge.o c_bridges/uri-bridge.o c_bridges/dotenv-bridge.o c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o; do
+          for lib in vendor/bdwgc/libgc.a vendor/yyjson/libyyjson.a vendor/libuv/build/libuv.a vendor/picohttpparser/picohttpparser.o vendor/rure/librure.a c_bridges/lws-bridge.o c_bridges/multipart-bridge.o c_bridges/regex-bridge.o c_bridges/child-process-bridge.o c_bridges/child-process-spawn.o c_bridges/trampoline-bridge.o c_bridges/os-bridge.o c_bridges/strlen-cache.o c_bridges/time-bridge.o c_bridges/base64-bridge.o c_bridges/url-bridge.o c_bridges/uri-bridge.o c_bridges/dotenv-bridge.o c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/scram-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o; do
             if [ ! -f "$lib" ]; then
               echo "MISSING: $lib"
               fail=1
@@ -509,14 +517,15 @@ jobs:
           cp c_bridges/multipart-bridge.o release/lib/
           cp c_bridges/regex-bridge.o release/lib/
           cp c_bridges/net-bridge.o release/lib/
+          cp c_bridges/scram-bridge.o release/lib/
           cp vendor/rure/librure.a release/lib/
           cp c_bridges/child-process-bridge.o release/lib/
           cp c_bridges/child-process-spawn.o release/lib/
           cp c_bridges/trampoline-bridge.o release/lib/
           cp c_bridges/os-bridge.o c_bridges/strlen-cache.o release/lib/
           cp c_bridges/time-bridge.o c_bridges/base64-bridge.o c_bridges/url-bridge.o c_bridges/uri-bridge.o release/lib/
           cp c_bridges/dotenv-bridge.o release/lib/
-          cp c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o release/lib/
+          cp c_bridges/watch-bridge.o c_bridges/arena-bridge.o c_bridges/curl-bridge.o c_bridges/pg-bridge.o c_bridges/scram-bridge.o c_bridges/compress-bridge.o c_bridges/yaml-bridge.o c_bridges/string-ops-bridge.o c_bridges/llvm-bridge.o c_bridges/llvm-builder-bridge.o c_bridges/lld-bridge.o release/lib/
           tar -czf chadscript-macos-arm64.tar.gz -C release chad lib
 
       - name: Upload artifact
@@ -588,6 +597,7 @@ jobs:
             multipart-bridge.o \
             regex-bridge.o \
             net-bridge.o \
+            scram-bridge.o \
             librure.a \
             child-process-bridge.o \
             child-process-spawn.o \

c_bridges/scram-bridge.c

@@ -0,0 +1,283 @@
+// scram-bridge.c — SCRAM-SHA-256 primitives for the ChadScript pg driver.
+//
+// Exposes four entry points callable from ChadScript via `declare function`:
+//
+//   cs_scram_random_nonce_b64()                     -> string
+//   cs_scram_client_first_bare(user, nonce_b64)     -> string ("n=<saslname>,r=<nonce>")
+//   cs_scram_client_final(password, client_first_bare, server_first) -> string
+//      returns "<client-final-message>\x01<server-signature-b64>"; caller splits on \x01
+//   cs_scram_is_valid_server_final(server_final, expected_sig_b64) -> int (1/0)
+//
+// All strings are null-terminated, GC_malloc_atomic-allocated (Boehm GC).
+// Base64 encoding follows RFC 4648 (standard alphabet, '=' padding) which is
+// what RFC 5802 §3 specifies for SCRAM attributes.
+
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <openssl/hmac.h>
+#include <openssl/sha.h>
+#include <openssl/evp.h>
+#include <openssl/rand.h>
+
+extern void* GC_malloc_atomic(size_t sz);
+extern void* GC_malloc(size_t sz);
+
+// ---- base64 (standard, padded) ---------------------------------------------
+
+static const char B64_ENC[65] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static char* b64_encode(const unsigned char* in, size_t in_len) {
+    size_t out_len = ((in_len + 2) / 3) * 4;
+    char* out = (char*)GC_malloc_atomic(out_len + 1);
+    size_t i = 0, j = 0;
+    while (i < in_len) {
+        unsigned int a = in[i++];
+        int has_b = (i < in_len);
+        unsigned int b = has_b ? in[i++] : 0;
+        int has_c = (i < in_len);
+        unsigned int c = has_c ? in[i++] : 0;
+        unsigned int triple = (a << 16) | (b << 8) | c;
+        out[j++] = B64_ENC[(triple >> 18) & 0x3F];
+        out[j++] = B64_ENC[(triple >> 12) & 0x3F];
+        out[j++] = has_b ? B64_ENC[(triple >> 6) & 0x3F] : '=';
+        out[j++] = has_c ? B64_ENC[triple & 0x3F] : '=';
+    }
+    out[j] = '\0';
+    return out;
+}
+
+static const signed char B64_DEC[256] = {
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
+    52,53,54,55,56,57,58,59,60,61,-1,-1,-1, 0,-1,-1,
+    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
+    15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
+    -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
+    41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+    -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
+};
+
+// Returns bytes decoded into out (caller allocates); returns byte length written.
+static size_t b64_decode_into(const char* in, unsigned char* out) {
+    size_t in_len = strlen(in);
+    size_t out_pos = 0;
+    int buf = 0, bits = 0;
+    for (size_t i = 0; i < in_len; i++) {
+        unsigned char ch = (unsigned char)in[i];
+        if (ch == '=') break;
+        signed char v = B64_DEC[ch];
+        if (v < 0) continue;
+        buf = (buf << 6) | v;
+        bits += 6;
+        if (bits >= 8) {
+            bits -= 8;
+            out[out_pos++] = (unsigned char)((buf >> bits) & 0xFF);
+            buf &= (1 << bits) - 1;
+        }
+    }
+    return out_pos;
+}
+
+// ---- helpers ----------------------------------------------------------------
+
+static char* escape_saslname(const char* user) {
+    size_t in_len = strlen(user);
+    // Worst case every char becomes 3 bytes.
+    char* out = (char*)GC_malloc_atomic(in_len * 3 + 1);
+    size_t j = 0;
+    for (size_t i = 0; i < in_len; i++) {
+        char c = user[i];
+        if (c == '=') { out[j++]='='; out[j++]='3'; out[j++]='D'; }
+        else if (c == ',') { out[j++]='='; out[j++]='2'; out[j++]='C'; }
+        else { out[j++] = c; }
+    }
+    out[j] = '\0';
+    return out;
+}
+
+// Parse a SCRAM attribute list "k1=v1,k2=v2,...". Returns malloc'd value for
+// the first matching key, or NULL. Uses stdlib malloc then caller free — but
+// for our single-use call sites we copy into GC memory.
+static int find_attr(const char* s, char key, char* out, size_t out_sz) {
+    size_t len = strlen(s);
+    size_t start = 0;
+    for (size_t i = 0; i <= len; i++) {
+        if (i == len || s[i] == ',') {
+            // segment [start, i)
+            if (i > start + 1 && s[start] == key && s[start + 1] == '=') {
+                size_t vlen = i - (start + 2);
+                if (vlen >= out_sz) vlen = out_sz - 1;
+                memcpy(out, s + start + 2, vlen);
+                out[vlen] = '\0';
+                return 1;
+            }
+            start = i + 1;
+        }
+    }
+    return 0;
+}
+
+// ---- public API -------------------------------------------------------------
+
+// 18 random bytes → base64. Matches libpq's client nonce size.
+const char* cs_scram_random_nonce_b64(void) {
+    unsigned char raw[18];
+    if (RAND_bytes(raw, 18) != 1) {
+        // Fallback: fill with zeros (extremely unlikely path). Still produces
+        // a valid-looking string; the server will reject on signature anyway.
+        memset(raw, 0, 18);
+    }
+    return b64_encode(raw, 18);
+}
+
+// client-first-bare = "n=<saslname>,r=<nonce>"
+const char* cs_scram_client_first_bare(const char* user, const char* nonce_b64) {
+    if (!user) user = "";
+    if (!nonce_b64) nonce_b64 = "";
+    char* escaped = escape_saslname(user);
+    size_t e_len = strlen(escaped);
+    size_t n_len = strlen(nonce_b64);
+    size_t total = 2 + e_len + 3 + n_len;
+    char* out = (char*)GC_malloc_atomic(total + 1);
+    size_t j = 0;
+    out[j++] = 'n'; out[j++] = '=';
+    memcpy(out + j, escaped, e_len); j += e_len;
+    out[j++] = ','; out[j++] = 'r'; out[j++] = '=';
+    memcpy(out + j, nonce_b64, n_len); j += n_len;
+    out[j] = '\0';
+    return out;
+}
+
+// Derive client-final-message and server-signature. Returns a single string
+// of the form:  <client-final-message>\x01<server-signature-b64>
+// The caller splits on byte 0x01. Using an in-band separator keeps the FFI
+// a single string (ChadScript's `declare function` signature).
+const char* cs_scram_client_final(
+    const char* password,
+    const char* client_first_bare,
+    const char* server_first
+) {
+    if (!password) password = "";
+    if (!client_first_bare) client_first_bare = "";
+    if (!server_first) server_first = "";
+
+    char salt_b64[512];
+    char iter_str[32];
+    char combined_nonce[512];
+    if (!find_attr(server_first, 'r', combined_nonce, sizeof(combined_nonce)) ||
+        !find_attr(server_first, 's', salt_b64, sizeof(salt_b64)) ||
+        !find_attr(server_first, 'i', iter_str, sizeof(iter_str))) {
+        char* err = (char*)GC_malloc_atomic(8);
+        strcpy(err, "ERR");
+        return err;
+    }
+    int iter = atoi(iter_str);
+    if (iter < 1) {
+        char* err = (char*)GC_malloc_atomic(8);
+        strcpy(err, "ERR");
+        return err;
+    }
+
+    // Decode salt.
+    unsigned char salt[512];
+    size_t salt_len = b64_decode_into(salt_b64, salt);
+
+    // SaltedPassword = PBKDF2(HMAC-SHA-256, password, salt, iter, 32)
+    unsigned char salted[32];
+    if (PKCS5_PBKDF2_HMAC(password, (int)strlen(password),
+                          salt, (int)salt_len, iter,
+                          EVP_sha256(), 32, salted) != 1) {
+        char* err = (char*)GC_malloc_atomic(8);
+        strcpy(err, "ERR");
+        return err;
+    }
+
+    // ClientKey = HMAC-SHA-256(SaltedPassword, "Client Key")
+    unsigned char client_key[32];
+    unsigned int ck_len = 32;
+    HMAC(EVP_sha256(), salted, 32,
+         (const unsigned char*)"Client Key", 10, client_key, &ck_len);
+
+    // StoredKey = SHA-256(ClientKey)
+    unsigned char stored_key[32];
+    SHA256(client_key, 32, stored_key);
+
+    // AuthMessage = client_first_bare + "," + server_first + "," + client_final_no_proof
+    // where client_final_no_proof = "c=biws,r=" + combined_nonce
+    size_t cfb_len = strlen(client_first_bare);
+    size_t sf_len = strlen(server_first);
+    size_t cn_len = strlen(combined_nonce);
+    const char* cfwp_prefix = "c=biws,r=";
+    size_t cfwp_prefix_len = 9;
+    size_t cfwp_len = cfwp_prefix_len + cn_len;
+    size_t auth_len = cfb_len + 1 + sf_len + 1 + cfwp_len;
+    unsigned char* auth = (unsigned char*)GC_malloc_atomic(auth_len);
+    size_t p = 0;
+    memcpy(auth + p, client_first_bare, cfb_len); p += cfb_len;
+    auth[p++] = ',';
+    memcpy(auth + p, server_first, sf_len); p += sf_len;
+    auth[p++] = ',';
+    memcpy(auth + p, cfwp_prefix, cfwp_prefix_len); p += cfwp_prefix_len;
+    memcpy(auth + p, combined_nonce, cn_len); p += cn_len;
+
+    // ClientSignature = HMAC-SHA-256(StoredKey, AuthMessage)
+    unsigned char client_sig[32];
+    unsigned int cs_len = 32;
+    HMAC(EVP_sha256(), stored_key, 32, auth, auth_len, client_sig, &cs_len);
+
+    // ClientProof = ClientKey XOR ClientSignature
+    unsigned char proof[32];
+    for (int i = 0; i < 32; i++) proof[i] = client_key[i] ^ client_sig[i];
+    char* proof_b64 = b64_encode(proof, 32);
+
+    // ServerKey = HMAC-SHA-256(SaltedPassword, "Server Key")
+    unsigned char server_key[32];
+    unsigned int sk_len = 32;
+    HMAC(EVP_sha256(), salted, 32,
+         (const unsigned char*)"Server Key", 10, server_key, &sk_len);
+
+    // ServerSignature = HMAC-SHA-256(ServerKey, AuthMessage)
+    unsigned char server_sig[32];
+    unsigned int ss_len = 32;
+    HMAC(EVP_sha256(), server_key, 32, auth, auth_len, server_sig, &ss_len);
+    char* server_sig_b64 = b64_encode(server_sig, 32);
+
+    // Assemble: "c=biws,r=<nonce>,p=<proof>" + '\x01' + server_sig_b64
+    size_t proof_len = strlen(proof_b64);
+    size_t ss_b64_len = strlen(server_sig_b64);
+    size_t final_msg_len = cfwp_len + 3 + proof_len;
+    size_t total = final_msg_len + 1 + ss_b64_len;
+    char* out = (char*)GC_malloc_atomic(total + 1);
+    size_t j = 0;
+    memcpy(out + j, cfwp_prefix, cfwp_prefix_len); j += cfwp_prefix_len;
+    memcpy(out + j, combined_nonce, cn_len); j += cn_len;
+    out[j++] = ','; out[j++] = 'p'; out[j++] = '=';
+    memcpy(out + j, proof_b64, proof_len); j += proof_len;
+    out[j++] = '\x01';
+    memcpy(out + j, server_sig_b64, ss_b64_len); j += ss_b64_len;
+    out[j] = '\0';
+    return out;
+}
+
+// Verify the server-final-message "v=..." against the expected signature we
+// computed during client-final. Returns 1 on match, 0 on mismatch or error.
+double cs_scram_verify_server_final(const char* server_final, const char* expected_sig_b64) {
+    if (!server_final || !expected_sig_b64) return 0;
+    char verifier[128];
+    if (!find_attr(server_final, 'v', verifier, sizeof(verifier))) {
+        return 0;
+    }
+    if (strcmp(verifier, expected_sig_b64) == 0) return 1;
+    return 0;
+}