From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 27 May 2025 14:29:13 +0000 (+1000)
Subject: Enforce bad integer division math
X-Git-Tag: v1.59.0~105
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=ded594c0f9645415955de225de10a9c0edbb1e8a;p=btrtrc.git

Enforce bad integer division math
---

diff --git a/math.go b/math.go
index cd733e82..daf62b42 100644
--- a/math.go
+++ b/math.go
@@ -4,7 +4,7 @@ import (
 	"golang.org/x/exp/constraints"
 )
 
-func intCeilDiv[T constraints.Integer](a, b T) T {
+func intCeilDiv[T constraints.Unsigned](a, b T) T {
 	// This still sux for negative numbers due to truncating division. But I don't know that we need
 	// or ceil division makes sense for negative numbers.
 	return (a + b - 1) / b
diff --git a/torrent.go b/torrent.go
index d68c3f49..a1dc80d5 100644
--- a/torrent.go
+++ b/torrent.go
@@ -538,8 +538,7 @@ func (t *Torrent) setInfo(info *metainfo.Info) error {
 	t.info = info
 	t.getInfoCtxCancel(errors.New("got info"))
 	t.nameMu.Unlock()
-	t._chunksPerRegularPiece = chunkIndexType(
-		(pp.Integer(t.usualPieceSize()) + t.chunkSize - 1) / t.chunkSize)
+	t._chunksPerRegularPiece = chunkIndexType(intCeilDiv(pp.Integer(t.usualPieceSize()), t.chunkSize))
 	t.deferUpdateComplete()
 	t.displayName = "" // Save a few bytes lol.
 	t.initFiles()
@@ -3053,7 +3052,7 @@ func (t *Torrent) addWebSeed(url string, opts ...AddWebSeedsOpt) bool {
 	g.MakeMapWithCap(&ws.activeRequests, ws.client.MaxRequests)
 	// TODO: Implement an algorithm that assigns this based on sharing chunks across peers. For now
 	// we just allow 2 MiB worth of requests. See newHotPeerImpl.nominalMaxRequests.
-	ws.peer.PeerMaxRequests = intCeilDiv(2<<20, ws.peer.t.chunkSize.Int())
+	ws.peer.PeerMaxRequests = maxRequests(intCeilDiv(8<<20, ws.peer.t.chunkSize.Uint32()))
 	ws.peer.initUpdateRequestsTimer()
 	ws.locker = t.cl.locker()
 	for _, f := range t.callbacks().NewPeer {