contractTerms was missing, looks like in commit f11483b5 a move was intended

2 files changed, 358 insertions, 0 deletions

diff --git a/packages/taler-util/src/contractTerms.test.ts b/packages/taler-util/src/contractTerms.test.ts
new file mode 100644
index 000000000..74cae4ca7
--- /dev/null
+++ b/packages/taler-util/src/contractTerms.test.ts
@@ -0,0 +1,122 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+/**
+ * Imports.
+ */
+import test from "ava";
+import { ContractTermsUtil } from "./contractTerms.js";
+
+test("contract terms canon hashing", (t) => {
+  const cReq = {
+    foo: 42,
+    bar: "hello",
+    $forgettable: {
+      foo: true,
+    },
+  };
+
+  const c1 = ContractTermsUtil.saltForgettable(cReq);
+  const c2 = ContractTermsUtil.saltForgettable(cReq);
+  t.assert(typeof cReq.$forgettable.foo === "boolean");
+  t.assert(typeof c1.$forgettable.foo === "string");
+  t.assert(c1.$forgettable.foo !== c2.$forgettable.foo);
+
+  const h1 = ContractTermsUtil.hashContractTerms(c1);
+
+  const c3 = ContractTermsUtil.scrub(JSON.parse(JSON.stringify(c1)));
+
+  t.assert(c3.foo === undefined);
+  t.assert(c3.bar === cReq.bar);
+
+  const h2 = ContractTermsUtil.hashContractTerms(c3);
+
+  t.deepEqual(h1, h2);
+});
+
+test("contract terms canon hashing (nested)", (t) => {
+  const cReq = {
+    foo: 42,
+    bar: {
+      prop1: "hello, world",
+      $forgettable: {
+        prop1: true,
+      },
+    },
+    $forgettable: {
+      bar: true,
+    },
+  };
+
+  const c1 = ContractTermsUtil.saltForgettable(cReq);
+
+  t.is(typeof c1.$forgettable.bar, "string");
+  t.is(typeof c1.bar.$forgettable.prop1, "string");
+
+  const forgetPath = (x: any, s: string) =>
+    ContractTermsUtil.forgetAll(x, (p) => p.join(".") === s);
+
+  // Forget bar first
+  const c2 = forgetPath(c1, "bar");
+
+  // Forget bar.prop1 first
+  const c3 = forgetPath(forgetPath(c1, "bar.prop1"), "bar");
+
+  // Forget everything
+  const c4 = ContractTermsUtil.scrub(c1);
+
+  const h1 = ContractTermsUtil.hashContractTerms(c1);
+  const h2 = ContractTermsUtil.hashContractTerms(c2);
+  const h3 = ContractTermsUtil.hashContractTerms(c3);
+  const h4 = ContractTermsUtil.hashContractTerms(c4);
+
+  t.is(h1, h2);
+  t.is(h1, h3);
+  t.is(h1, h4);
+
+  // Doesn't contain salt
+  t.false(ContractTermsUtil.validateForgettable(cReq));
+
+  t.true(ContractTermsUtil.validateForgettable(c1));
+  t.true(ContractTermsUtil.validateForgettable(c2));
+  t.true(ContractTermsUtil.validateForgettable(c3));
+  t.true(ContractTermsUtil.validateForgettable(c4));
+});
+
+test("contract terms reference vector", (t) => {
+  const j = {
+    k1: 1,
+    $forgettable: {
+      k1: "SALT",
+    },
+    k2: {
+      n1: true,
+      $forgettable: {
+        n1: "salt",
+      },
+    },
+    k3: {
+      n1: "string",
+    },
+  };
+
+  const h = ContractTermsUtil.hashContractTerms(j);
+
+  t.deepEqual(
+    h,
+    "VDE8JPX0AEEE3EX1K8E11RYEWSZQKGGZCV6BWTE4ST1C8711P7H850Z7F2Q2HSSYETX87ERC2JNHWB7GTDWTDWMM716VKPSRBXD7SRR",
+  );
+});
diff --git a/packages/taler-util/src/contractTerms.ts b/packages/taler-util/src/contractTerms.ts
new file mode 100644
index 000000000..fa162e719
--- /dev/null
+++ b/packages/taler-util/src/contractTerms.ts
@@ -0,0 +1,236 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import { canonicalJson } from "./helpers.js";
+import { Logger } from "./logging.js";
+import { kdf } from "./kdf.js";
+import {
+  decodeCrock,
+  encodeCrock,
+  getRandomBytes,
+  hash,
+  stringToBytes,
+} from "./talerCrypto.js";
+
+const logger = new Logger("contractTerms.ts");
+
+
+
+
+export namespace ContractTermsUtil {
+
+  export function forgetAllImpl(
+    anyJson: any,
+    path: string[],
+    pred: PathPredicate,
+  ): any {
+    const dup = JSON.parse(JSON.stringify(anyJson));
+    if (Array.isArray(dup)) {
+      for (let i = 0; i < dup.length; i++) {
+        dup[i] = forgetAllImpl(dup[i], [...path, `${i}`], pred);
+      }
+    } else if (typeof dup === "object" && dup != null) {
+      if (typeof dup.$forgettable === "object") {
+        for (const x of Object.keys(dup.$forgettable)) {
+          if (!pred([...path, x])) {
+            continue;
+          }
+          if (!dup.$forgotten) {
+            dup.$forgotten = {};
+          }
+          if (!dup.$forgotten[x]) {
+            const membValCanon = stringToBytes(
+              canonicalJson(scrub(dup[x])) + "\0",
+            );
+            const membSalt = stringToBytes(dup.$forgettable[x] + "\0");
+            const h = kdf(64, membValCanon, membSalt, new Uint8Array([]));
+            dup.$forgotten[x] = encodeCrock(h);
+          }
+          delete dup[x];
+          delete dup.$forgettable[x];
+        }
+        if (Object.keys(dup.$forgettable).length === 0) {
+          delete dup.$forgettable;
+        }
+      }
+      for (const x of Object.keys(dup)) {
+        if (x.startsWith("$")) {
+          continue;
+        }
+        dup[x] = forgetAllImpl(dup[x], [...path, x], pred);
+      }
+    }
+    return dup;
+  }
+
+
+  export type PathPredicate = (path: string[]) => boolean;
+
+  /**
+   * Scrub all forgettable members from an object.
+   */
+  export function scrub(anyJson: any): any {
+    return forgetAllImpl(anyJson, [], () => true);
+  }
+
+  /**
+   * Recursively forget all forgettable members of an object,
+   * where the path matches a predicate.
+   */
+  export function forgetAll(anyJson: any, pred: PathPredicate): any {
+    return forgetAllImpl(anyJson, [], pred);
+  }
+
+  /**
+   * Generate a salt for all members marked as forgettable,
+   * but which don't have an actual salt yet.
+   */
+  export function saltForgettable(anyJson: any): any {
+    const dup = JSON.parse(JSON.stringify(anyJson));
+    if (Array.isArray(dup)) {
+      for (let i = 0; i < dup.length; i++) {
+        dup[i] = saltForgettable(dup[i]);
+      }
+    } else if (typeof dup === "object" && dup !== null) {
+      if (typeof dup.$forgettable === "object") {
+        for (const k of Object.keys(dup.$forgettable)) {
+          if (dup.$forgettable[k] === true) {
+            dup.$forgettable[k] = encodeCrock(getRandomBytes(32));
+          }
+        }
+      }
+      for (const x of Object.keys(dup)) {
+        if (x.startsWith("$")) {
+          continue;
+        }
+        dup[x] = saltForgettable(dup[x]);
+      }
+    }
+    return dup;
+  }
+
+  const nameRegex = /^[0-9A-Za-z_]+$/;
+
+  /**
+   * Check that the given JSON object is well-formed with regards
+   * to forgettable fields and other restrictions for forgettable JSON.
+   */
+  export function validateForgettable(anyJson: any): boolean {
+    if (typeof anyJson === "string") {
+      return true;
+    }
+    if (typeof anyJson === "number") {
+      return (
+        Number.isInteger(anyJson) &&
+        anyJson >= Number.MIN_SAFE_INTEGER &&
+        anyJson <= Number.MAX_SAFE_INTEGER
+      );
+    }
+    if (typeof anyJson === "boolean") {
+      return true;
+    }
+    if (anyJson === null) {
+      return true;
+    }
+    if (Array.isArray(anyJson)) {
+      return anyJson.every((x) => validateForgettable(x));
+    }
+    if (typeof anyJson === "object") {
+      for (const k of Object.keys(anyJson)) {
+        if (k.match(nameRegex)) {
+          if (validateForgettable(anyJson[k])) {
+            continue;
+          } else {
+            return false;
+          }
+        }
+        if (k === "$forgettable") {
+          const fga = anyJson.$forgettable;
+          if (!fga || typeof fga !== "object") {
+            return false;
+          }
+          for (const fk of Object.keys(fga)) {
+            if (!fk.match(nameRegex)) {
+              return false;
+            }
+            if (!(fk in anyJson)) {
+              return false;
+            }
+            const fv = anyJson.$forgettable[fk];
+            if (typeof fv !== "string") {
+              return false;
+            }
+          }
+        } else if (k === "$forgotten") {
+          const fgo = anyJson.$forgotten;
+          if (!fgo || typeof fgo !== "object") {
+            return false;
+          }
+          for (const fk of Object.keys(fgo)) {
+            if (!fk.match(nameRegex)) {
+              return false;
+            }
+            // Check that the value has actually been forgotten.
+            if (fk in anyJson) {
+              return false;
+            }
+            const fv = anyJson.$forgotten[fk];
+            if (typeof fv !== "string") {
+              return false;
+            }
+            try {
+              const decFv = decodeCrock(fv);
+              if (decFv.length != 64) {
+                return false;
+              }
+            } catch (e) {
+              return false;
+            }
+            // Check that salt has been deleted after forgetting.
+            if (anyJson.$forgettable?.[k] !== undefined) {
+              return false;
+            }
+          }
+        } else {
+          return false;
+        }
+      }
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Check that no forgettable information has been forgotten.
+   *
+   * Must only be called on an object already validated with validateForgettable.
+   */
+  export function validateNothingForgotten(contractTerms: any): boolean {
+    throw Error("not implemented yet");
+  }
+
+  /**
+   * Hash a contract terms object.  Forgettable fields
+   * are scrubbed and JSON canonicalization is applied
+   * before hashing.
+   */
+  export function hashContractTerms(contractTerms: unknown): string {
+    const cleaned = scrub(contractTerms);
+    const canon = canonicalJson(cleaned) + "\0";
+    const bytes = stringToBytes(canon);
+    return encodeCrock(hash(bytes));
+  }
+}