From b52f00492e4c6ff199488e1997fff19a8e158bb7 Mon Sep 17 00:00:00 2001
From: Tomay <tomay3000@gmail.com>
Date: Fri, 11 Jun 2021 00:23:46 +0200
Subject: [PATCH] Fix checks for wxPalette index validity

Consistently check that the index is valid in all ports, instead of
using hard-coded 255 rather than the actual number of colours in some of
them and forgetting to check that the index is positive in others.

Closes #19198.
---
 src/generic/paletteg.cpp | 7 +++++--
 src/msw/palette.cpp      | 2 +-
 src/osx/palette.cpp      | 2 +-
 src/x11/palette.cpp      | 2 +-
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/generic/paletteg.cpp b/src/generic/paletteg.cpp
index af3fe56e93..6b3530e864 100644
--- a/src/generic/paletteg.cpp
+++ b/src/generic/paletteg.cpp
@@ -131,8 +131,11 @@ bool wxPalette::GetRGB(int pixel,
                        unsigned char *green,
                        unsigned char *blue) const
 {
-    if (!m_refData) return false;
-    if (pixel >= M_PALETTEDATA->m_count) return false;
+    if ( !m_refData )
+        return false;
+
+    if ( pixel < 0 || pixel >= M_PALETTEDATA->m_count )
+        return false;
 
     wxPaletteEntry& p = M_PALETTEDATA->m_entries[pixel];
     if (red) *red = p.red;
diff --git a/src/msw/palette.cpp b/src/msw/palette.cpp
index 6d430f9b7a..e4584a5bb5 100644
--- a/src/msw/palette.cpp
+++ b/src/msw/palette.cpp
@@ -156,7 +156,7 @@ bool wxPalette::GetRGB(int index,
     if ( !m_refData )
         return false;
 
-    if (index < 0 || index > 255)
+    if ( index < 0 || index >= GetColoursCount() )
         return false;
 
     PALETTEENTRY entry;
diff --git a/src/osx/palette.cpp b/src/osx/palette.cpp
index e0519daa13..0d388946a3 100644
--- a/src/osx/palette.cpp
+++ b/src/osx/palette.cpp
@@ -122,7 +122,7 @@ bool wxPalette::GetRGB(int index, unsigned char *red, unsigned char *green, unsi
     if ( !m_refData )
         return false;
 
-    if (index < 0 || index >= M_PALETTEDATA->m_count)
+    if ( index < 0 || index >= M_PALETTEDATA->m_count )
         return false;
 
     const wxColour& col = M_PALETTEDATA->m_palette[index] ;
diff --git a/src/x11/palette.cpp b/src/x11/palette.cpp
index 1cdf8bc4ad..1559ecac17 100644
--- a/src/x11/palette.cpp
+++ b/src/x11/palette.cpp
@@ -242,7 +242,7 @@ bool wxPalette::GetRGB(int index,
     if ( !m_refData )
         return false;
 
-    if (index < 0 || index > 255)
+    if ( index < 0 || index >= GetColoursCount() )
         return false;
 
     wxList::compatibility_iterator node = M_PALETTEDATA->m_palettes.GetFirst();