Revert "refactor: change signature requirements for justifications and user settings"

package.json

@@ -13,7 +13,7 @@
     "commitmsg": "kleros-scripts commitmsg",
     "cz": "kleros-scripts cz",
     "invoke": "env-cmd ./.env serverless invoke -l -f",
-    "build": "docker run --rm -v $PWD:/data -w /data lambci/lambda:build-nodejs8.10 npm rebuild scrypt",
+    "build": "docker run --rm -v $PWD:/data -w /data node:8 npm rebuild scrypt",
     "deploy:function": "env-cmd ./.env serverless deploy function -f",
     "deploy:staging": "env-cmd ./.env serverless deploy",
     "deploy": "env-cmd ./.env serverless deploy -s production"

serverless.yml

@@ -251,12 +251,7 @@ functions:
       - {
           Effect: Allow,
           Action: ['dynamodb:Query'],
-          Resource: 'arn:aws:dynamodb:us-east-2:547511976516:table/kovan-justifications',
-        }
-      - {
-          Effect: Allow,
-          Action: ['dynamodb:Query'],
-          Resource: 'arn:aws:dynamodb:us-east-2:547511976516:table/mainnet-justifications',
+          Resource: 'arn:aws:dynamodb:us-east-2:547511976516:table/justifications',
         }
     documentation:
       summary: 'Get justifications for a dispute round.'
@@ -295,12 +290,7 @@ functions:
       - {
           Effect: Allow,
           Action: ['dynamodb:PutItem'],
-          Resource: 'arn:aws:dynamodb:us-east-2:547511976516:table/kovan-justifications',
-        }
-      - {
-          Effect: Allow,
-          Action: ['dynamodb:PutItem'],
-          Resource: 'arn:aws:dynamodb:us-east-2:547511976516:table/mainnet-justifications',
+          Resource: 'arn:aws:dynamodb:us-east-2:547511976516:table/justifications',
         }
     documentation:
       summary: 'Put justification for a vote.'

src/court/justifications.js

@@ -17,7 +17,7 @@ module.exports.get = async (event, _context, callback) => {
             }
           },
           KeyConditionExpression: 'disputeIDAndAppeal = :disputeIDAndAppeal',
-          TableName: `${payload.network}-justifications`
+          TableName: 'justifications'
         })
       }
     })
@@ -32,63 +32,71 @@ module.exports.put = async (event, _context, callback) => {
     process.env.KLEROS_LIQUID_ADDRESS
   )
 
+  // Validate signature
   const payload = JSON.parse(event.body).payload
-
-  // Verify votes belong to user
-  const dispute = await klerosLiquid.methods.getDispute(
-    payload.justification.disputeID
-  ).call()
-
-  // Get number of votes in current round
-  const votesInRound = dispute.votesLengths[payload.justification.appeal]
-
-  let drawn = false
-  let voteID
-  for (let i = 0; i < Number(votesInRound); i++) {
-    const vote = await klerosLiquid.methods
-      .getVote(payload.justification.disputeID, payload.justification.appeal, i)
-      .call()
-    if (vote.account === payload.address) {
-      // If voted, can no longer submit justification.
-      if (vote.voted) {
-        return callback(null, {
-          statusCode: 403,
-          headers: { 'Access-Control-Allow-Origin': '*' },
-          body: JSON.stringify({
-            error: 'This address has already cast their vote.'
-          })
-        })
-      }
-      // Once we know address has been drawn we can stop searching.
-      drawn = true
-      voteID = i
-      break
-    }
-  }
-
-  if (!drawn) {
+  try {
+    if (
+      (await web3.eth.accounts.recover(
+        JSON.stringify(payload.justification),
+        payload.signature
+      )) !==
+      (await dynamoDB.getItem({
+        Key: { address: { S: payload.address } },
+        TableName: 'user-settings',
+        ProjectionExpression: 'derivedAccountAddress'
+      })).Item.derivedAccountAddress.S
+    )
+      throw new Error(
+        "Signature does not match the supplied address' derived account address for justifications."
+      )
+  } catch (err) {
+    console.error(err)
     return callback(null, {
       statusCode: 403,
       headers: { 'Access-Control-Allow-Origin': '*' },
       body: JSON.stringify({
-        error: 'This address was not drawn.'
+        error:
+          "Signature is invalid or does not match the supplied address' derived account address for justifications."
       })
     })
   }
 
-  // Save justification.
+  // Verify votes belong to user
+  for (const voteID of payload.justification.voteIDs) {
+    const vote = await klerosLiquid.methods
+      .getVote(
+        payload.justification.disputeID,
+        payload.justification.appeal,
+        voteID
+      )
+      .call()
+    if (vote.account !== payload.address || vote.voted)
+      return callback(null, {
+        statusCode: 403,
+        headers: { 'Access-Control-Allow-Origin': '*' },
+        body: JSON.stringify({
+          error:
+            'Not all of the supplied vote IDs belong to the supplied address and are not cast.'
+        })
+      })
+  }
+
+  // Save justification
   await dynamoDB.putItem({
     Item: {
       disputeIDAndAppeal: {
         S: `${payload.justification.disputeID}-${payload.justification.appeal}`
       },
-      address: {
-        S: payload.address
+      voteID: {
+        N: String(
+          payload.justification.voteIDs[
+            payload.justification.voteIDs.length - 1
+          ]
+        )
       },
-      voteID: { N: String(voteID) },
       justification: { S: payload.justification.justification }
     },
-    TableName: `${payload.network}-justifications`
+    TableName: 'justifications'
   })
   callback(null, {
     statusCode: 200,

src/global/user-settings.js

@@ -27,19 +27,16 @@ module.exports.get = async (event, _context, callback) => {
   // Validate signature
   const payload = JSON.parse(event.body).payload
   try {
-    const account = await web3.eth.accounts.recover(
-      JSON.stringify(payload.settings),
-      payload.signature
-    )
-    // accept if sig is from account or derived account
     if (
-      account !== payload.address &&
-      account !==
-        (await dynamoDB.getItem({
-          Key: { address: { S: payload.address } },
-          TableName: 'user-settings',
-          ProjectionExpression: 'derivedAccountAddress'
-        })).Item.derivedAccountAddress.S
+      (await web3.eth.accounts.recover(
+        JSON.stringify(payload.settings),
+        payload.signature
+      )) !==
+      (await dynamoDB.getItem({
+        Key: { address: { S: payload.address } },
+        TableName: 'user-settings',
+        ProjectionExpression: 'derivedAccountAddress'
+      })).Item.derivedAccountAddress.S
     )
       throw new Error('Signature does not match supplied address.')
   } catch (err) {