1 files changed, 12 insertions, 0 deletions
diff --git a/internal/game/cmd_walk.go b/internal/game/cmd_walk.go
index 101c0fe..c9e7c0a 100644
--- a/internal/game/cmd_walk.go
+++ b/internal/game/cmd_walk.go
@@ -42,16 +42,28 @@ func (g *Game) doWalk(sess *net.Session, args []string) {
 
 func parseWalkDirections(input string) ([]string, error) {
 	var dirs []string
+	total := 0
+	// maxWalkSteps bounds the slice before it is allocated. Agility caps a
+	// real walk well below this; the limit exists only so a hostile count
+	// like "walk 999999999n" cannot allocate gigabytes on the owner goroutine.
+	const maxWalkSteps = 1000
 	i := 0
 	for i < len(input) {
 		num := 0
 		for i < len(input) && input[i] >= '0' && input[i] <= '9' {
 			num = num*10 + int(input[i]-'0')
+			if num > maxWalkSteps {
+				return nil, fmt.Errorf("too many steps at once (limit %d)", maxWalkSteps)
+			}
 			i++
 		}
 		if num == 0 {
 			num = 1
 		}
+		total += num
+		if total > maxWalkSteps {
+			return nil, fmt.Errorf("too many steps at once (limit %d)", maxWalkSteps)
+		}
 		if i >= len(input) {
 			return nil, fmt.Errorf("unexpected end of directions")
 		}