pgp: parse s2k gnu extensions.

See: handshake-org/hs-airdrop#44
bcoin-org · Feb 20, 2020 · 2a1d2e2 · 2a1d2e2
1 parent 76266c9
commit 2a1d2e2
Showing 1 changed file with 60 additions and 6 deletions.
diff --git a/lib/pgp.js b/lib/pgp.js
@@ -1392,6 +1392,7 @@ class S2K extends bio.Struct {
     this.hash = 0;
     this.count = 0;
     this.salt = EMPTY;
+    this.serial = EMPTY;
   }
 
   derive(passphrase, size) {
@@ -1511,6 +1512,16 @@ class S2K extends bio.Struct {
         size += 8;
         size += 1;
         break;
+      case 1001:
+        size += 3;
+        size += 1;
+        break;
+      case 1002:
+        size += 3;
+        size += 1;
+        size += 1;
+        size += this.serial.length;
+        break;
       default:
         throw new Error('Unknown S2K function.');
     }
@@ -1519,7 +1530,7 @@ class S2K extends bio.Struct {
   }
 
   write(bw) {
-    bw.writeU8(this.mode);
+    bw.writeU8(this.mode >= 1000 ? 101 : this.mode);
     bw.writeU8(this.hash);
 
     switch (this.mode) {
@@ -1532,6 +1543,16 @@ class S2K extends bio.Struct {
         bw.writeBytes(this.salt);
         bw.writeU8(encodeCount(this.count));
         break;
+      case 1001:
+        bw.writeString('GNU', 'binary');
+        bw.writeU8(1);
+        break;
+      case 1002:
+        bw.writeString('GNU', 'binary');
+        bw.writeU8(2);
+        bw.writeU8(this.serial.length);
+        bw.writeBytes(this.serial);
+        break;
       default:
         throw new Error('Unknown S2K function.');
     }
@@ -1544,17 +1565,49 @@ class S2K extends bio.Struct {
     this.hash = br.readU8();
 
     switch (this.mode) {
-      case 0:
+      case 0: {
         break;
-      case 1:
+      }
+
+      case 1: {
         this.salt = br.readBytes(8);
         break;
-      case 3:
+      }
+
+      case 3: {
         this.salt = br.readBytes(8);
         this.count = decodeCount(br.readU8());
         break;
-      default:
+      }
+
+      case 101: {
+        // GNU extensions.
+        // See: https://github.com/handshake-org/hs-airdrop/issues/44
+        const tag = br.readString(3, 'binary');
+
+        if (tag !== 'GNU')
+          throw new Error('Unknown S2K function.');
+
+        this.mode = 1000 + br.readU8();
+
+        switch (this.mode) {
+          case 1001:
+            // gnu-dummy
+            break;
+          case 1002:
+            // gnu-divert-to-card
+            this.serial = br.readBytes(Math.max(br.readU8(), 16));
+            break;
+          default:
+            throw new Error('Unknown S2K function.');
+        }
+
+        break;
+      }
+
+      default: {
         throw new Error('Unknown S2K function.');
+      }
     }
 
     return this;
@@ -1565,7 +1618,8 @@ class S2K extends bio.Struct {
       mode: this.mode,
       hash: hashTypesByVal[this.hash] || 'UNKNOWN',
       count: this.count,
-      salt: this.salt.toString('hex')
+      salt: this.salt.toString('hex'),
+      serial: this.serial.toString('hex')
     };
   }
 }