fix: cbor decode should not treat maps as objects (#36)

Author: birme

src/cat.ts

@@ -337,7 +337,8 @@ export class CommonAccessToken {
         plaintext as unknown as string,
         recipient
       );
-      const decoded = cbor.decode(coseMessage).value;
+      const decoder = new cbor.Decoder({ mapsAsObjects: false });
+      const decoded = decoder.decode(coseMessage).value;
       const coseTag = new cbor.Tag(decoded, 17);
       const cwtTag = new cbor.Tag(coseTag, CWT_TAG);
       this.data = cbor.encode(cwtTag);
@@ -358,18 +359,21 @@ export class CommonAccessToken {
       expectCwtTag: boolean;
     }
   ): Promise<void> {
-    const coseMessage = cbor.decode(token);
+    const decoder = new cbor.Decoder({ mapsAsObjects: false });
+    const coseMessage = decoder.decode(token);
     if (opts?.expectCwtTag && coseMessage.tag !== 61) {
       throw new Error('Expected CWT tag');
     }
     if (coseMessage.tag === CWT_TAG) {
       const cborCoseMessage = cbor.encode(coseMessage.value);
       const buf = await cose.mac.read(cborCoseMessage, key.k);
-      const json = await cbor.decode(buf);
+      const json = await decoder.decode(buf);
       this.payload = updateMapFromClaims(json);
     } else {
       const buf = await cose.mac.read(token, key.k);
-      this.payload = await cbor.decode(Buffer.from(buf.toString('hex'), 'hex'));
+      this.payload = await decoder.decode(
+        Buffer.from(buf.toString('hex'), 'hex')
+      );
     }
     this.kid = key.kid;
   }

src/catif.ts

@@ -1,4 +1,5 @@
 import { claimsToLabels, CommonAccessTokenDict, labelsToClaim } from './cat';
+import { CommonAccessTokenUri } from './catu';
 
 type CatIfValue = Map<number, [number, { [key: string]: string }]>;
 export type CommonAccessTokenIfMap = Map<number, CatIfValue>;
@@ -11,9 +12,59 @@ export type CatIfDictValue = {
   ];
 };
 
+const valueToDict: { [key: string]: (value: any) => any } = {
+  exp: (value) => {
+    const [code, headers, kid] = value;
+    return [code, valueToDict['location'](headers.get('Location')), kid];
+  },
+  location: (value) => {
+    if (typeof value === 'string') {
+      return { Location: value };
+    } else {
+      const [url, map] = value;
+      const obj: { [key: string]: any } = {};
+      (map as Map<string, any>).forEach((v, claim) => {
+        obj[claim] = valueToDict[claim] ? valueToDict[claim](v) : v;
+      });
+      return { Location: [url, obj] };
+    }
+  },
+  catu: (value) => CommonAccessTokenUri.fromUnlabeledMap(value).toDict()
+};
+
+const dictToValue: { [key: string]: (value: any) => any } = {
+  exp: (value) => {
+    const [code, headers, kid] = value;
+    return [code, dictToValue['location'](headers['Location']), kid];
+  },
+  location: (value) => {
+    if (typeof value === 'string') {
+      const map = new Map<string, any>();
+      map.set('Location', value);
+      return map;
+    } else {
+      const [url, dict] = value;
+      const lmap = new Map<string, any>();
+      for (const key in dict) {
+        lmap.set(
+          key,
+          dictToValue[key] ? dictToValue[key](dict[key]) : dict[key]
+        );
+      }
+      const map = new Map<string, any>();
+      map.set('Location', [url, lmap]);
+      return map;
+    }
+  },
+  catu: (value) => CommonAccessTokenUri.fromDict(value).payload
+};
+
 export class CommonAccessTokenIf {
   private catIfMap: CommonAccessTokenIfMap = new Map();
 
+  /**
+   * Create a CATIF claim from a dictionary with numbers as keys (labels)
+   */
   public static fromDictTags(dict: { [key: number]: any }) {
     const newDict: { [key: string]: any } = {};
     for (const key in dict) {
@@ -23,14 +74,24 @@ export class CommonAccessTokenIf {
     return CommonAccessTokenIf.fromDict(newDict);
   }
 
+  /**
+   * Create a CATIF claim from a dictionary with string as keys
+   */
   public static fromDict(dict: { [key: string]: any }) {
     const catif = new CommonAccessTokenIf();
     for (const catIfClaim in dict) {
-      catif.catIfMap.set(claimsToLabels[catIfClaim], dict[catIfClaim]);
+      const v = dict[catIfClaim];
+      catif.catIfMap.set(
+        claimsToLabels[catIfClaim],
+        dictToValue[catIfClaim] ? dictToValue[catIfClaim](v) : v
+      );
     }
     return catif;
   }
 
+  /**
+   * Create a CATIF claim from a map with string as keys
+   */
   public static fromMap(map: CommonAccessTokenIfMap) {
     const catif = new CommonAccessTokenIf();
     catif.catIfMap = map;
@@ -40,7 +101,8 @@ export class CommonAccessTokenIf {
   toDict() {
     const result: { [key: string]: any } = {};
     this.catIfMap.forEach((catIfValue, claim) => {
-      result[labelsToClaim[claim]] = catIfValue;
+      result[labelsToClaim[claim]] =
+        valueToDict[labelsToClaim[claim]](catIfValue);
     });
     return result;
   }

src/catu.ts

@@ -48,6 +48,9 @@ export type CommonAccessTokenUriMap = Map<number, UriPartMap>;
 export class CommonAccessTokenUri {
   private catuMap: CommonAccessTokenUriMap = new Map();
 
+  /**
+   * Create a CATU claim from a dictionary with numbers as keys (labels)
+   */
   public static fromDictTags(dict: { [key: number]: any }) {
     const newDict: { [key: string]: any } = {};
     for (const uriPartTag in dict) {
@@ -61,6 +64,9 @@ export class CommonAccessTokenUri {
     return CommonAccessTokenUri.fromDict(newDict);
   }
 
+  /**
+   * Create a CATU claim from a dictionary with string as keys
+   */
   public static fromDict(dict: { [key: string]: any }) {
     const catu = new CommonAccessTokenUri();
     for (const uriPart in dict) {
@@ -73,6 +79,25 @@ export class CommonAccessTokenUri {
     return catu;
   }
 
+  /**
+   * Create a CATU claim from a map with string as keys
+   */
+  public static fromUnlabeledMap(unLabeledMap: Map<string, any>) {
+    const map: CommonAccessTokenUriMap = new Map();
+    unLabeledMap.forEach((value, uriPart) => {
+      const uriPartLabel = uriPartToLabels[uriPart];
+      const matchMap = new Map<number, MatchValue>();
+      value.forEach((v: any, matchPart: string) => {
+        matchMap.set(matchToLabels[matchPart], v);
+      });
+      map.set(uriPartLabel, matchMap);
+    });
+    return CommonAccessTokenUri.fromMap(map);
+  }
+
+  /**
+   * Create a CATU claim from a map with number as keys
+   */
   public static fromMap(map: CommonAccessTokenUriMap) {
     const catu = new CommonAccessTokenUri();
     catu.catuMap = map;