pool: Correct account races.

The account and name fields of a client are not set until they are
received via a mining.authorize message and the account field is
accessed from separate goroutines which is a race.

This corrects that issue by introducing a separate mutex to protect both
the account and the name field and updating all references to by
protected by the mutex accordingly.

The name field doesn't appear to be used anywhere currently, however, it
would also be a race to access it without the mutex for the same reason,
so this takes the opportunity to ensure it is protected in case it is
used in the future.

pool/client.go

@@ -129,11 +129,15 @@ type Client struct {
 	reader      *bufio.Reader
 	ctx         context.Context
 	cancel      context.CancelFunc
-	name        string
 	extraNonce1 string
 	ch          chan Message
 	readCh      chan readPayload
-	account     string
+
+	// These fields track the client's account ID and name from the authorize
+	// message.
+	accountMtx sync.RWMutex
+	account    string
+	name       string
 
 	// These fields track the authorization and subscription status of
 	// the miner.
@@ -205,7 +209,7 @@ func (c *Client) claimWeightedShare() error {
 		return errs.PoolError(errs.ClaimShare, desc)
 	}
 	weight := ShareWeights[miner]
-	share := NewShare(c.account, weight)
+	share := NewShare(c.FetchAccountID(), weight)
 	return c.cfg.db.PersistShare(share)
 }
 
@@ -268,14 +272,17 @@ func (c *Client) handleAuthorizeRequest(req *Request, allowed bool) error {
 			}
 		}
 
+		c.accountMtx.Lock()
 		c.account = account.UUID
 		c.name = name
+		c.accountMtx.Unlock()
 
 	case true:
 		// Set a default account id.
+		c.accountMtx.Lock()
 		c.account = defaultAccountID
-
 		c.name = username
+		c.accountMtx.Unlock()
 	}
 
 	c.statusMtx.Lock()
@@ -614,7 +621,7 @@ func (c *Client) handleSubmitWorkRequest(ctx context.Context, req *Request, allo
 	// Create accepted work if the work submission is accepted
 	// by the mining node.
 	work := NewAcceptedWork(hash.String(), header.PrevBlock.String(),
-		header.Height, c.account, miner)
+		header.Height, c.FetchAccountID(), miner)
 	err = c.cfg.db.persistAcceptedWork(work)
 	if err != nil {
 		// If the submitted accepted work already exists, ignore the
@@ -916,6 +923,9 @@ func (c *Client) FetchMinerType() string {
 
 // FetchAccountID gets the client's account ID.
 func (c *Client) FetchAccountID() string {
+	defer c.accountMtx.RUnlock()
+	c.accountMtx.RLock()
+
 	return c.account
 }
 
@@ -968,11 +978,12 @@ func (c *Client) hashMonitor() {
 			miner := c.miner
 			c.mtx.RUnlock()
 
-			hashID := hashDataID(c.account, c.extraNonce1)
+			account := c.FetchAccountID()
+			hashID := hashDataID(account, c.extraNonce1)
 			hashData, err := c.cfg.db.fetchHashData(hashID)
 			if err != nil {
 				if errors.Is(err, errs.ValueNotFound) {
-					hashData = newHashData(miner, c.account, c.addr.String(),
+					hashData = newHashData(miner, account, c.addr.String(),
 						c.extraNonce1, hash)
 					err = c.cfg.db.persistHashData(hashData)
 					if err != nil {

pool/endpoint.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2019-2021 The Decred developers
+// Copyright (c) 2019-2023 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
@@ -221,7 +221,7 @@ func (e *Endpoint) generateHashIDs() map[string]struct{} {
 
 	ids := make(map[string]struct{}, len(e.clients))
 	for _, c := range e.clients {
-		hashID := hashDataID(c.account, c.extraNonce1)
+		hashID := hashDataID(c.FetchAccountID(), c.extraNonce1)
 		ids[hashID] = struct{}{}
 	}