From 57afd0ab37060795b8ae5a6b868a918a2ee75810 Mon Sep 17 00:00:00 2001
From: Tobias Frost <coldtobi@users.noreply.github.com>
Date: Sat, 2 Mar 2019 23:43:08 +0100
Subject: [PATCH] Fix range check bug in FileList::seek() (#13286)
When `count()` returns 0, `pos > (count()-1)` will always yield `true` due to integer underflow.
---
Marlin/src/lcd/extensible_ui/ui_api.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Marlin/src/lcd/extensible_ui/ui_api.cpp b/Marlin/src/lcd/extensible_ui/ui_api.cpp
index 88b5d35a4a..7165b5eefa 100644
--- a/Marlin/src/lcd/extensible_ui/ui_api.cpp
+++ b/Marlin/src/lcd/extensible_ui/ui_api.cpp
@@ -688,7 +688,7 @@ namespace ExtUI {
bool FileList::seek(const uint16_t pos, const bool skip_range_check) {
#if ENABLED(SDSUPPORT)
- if (!skip_range_check && pos > (count() - 1)) return false;
+ if (!skip_range_check && (pos + 1) > count()) return false;
const uint16_t nr =
#if ENABLED(SDCARD_RATHERRECENTFIRST) && DISABLED(SDCARD_SORT_ALPHA)
count() - 1 -
--
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