GuiTextBox(): Fix buffer overrun from cursor index (#405)

raysan5 · May 31, 2024 · 4b3d94f · 4b3d94f
1 parent 76f006b
commit 4b3d94f
Showing 1 changed file with 9 additions and 6 deletions.
diff --git a/src/raygui.h b/src/raygui.h
@@ -2464,7 +2464,10 @@ int GuiTextBox(Rectangle bounds, char *text, int textSize, bool editMode)
     int wrapMode = GuiGetStyle(DEFAULT, TEXT_WRAP_MODE);
 
     Rectangle textBounds = GetTextBounds(TEXTBOX, bounds);
-    int textWidth = GetTextWidth(text) - GetTextWidth(text + textBoxCursorIndex);
+    int textLength = (int)strlen(text);     // Get current text length
+    int thisCursorIndex = textBoxCursorIndex;
+    if (thisCursorIndex > textLength) thisCursorIndex = textLength;
+    int textWidth = GetTextWidth(text) - GetTextWidth(text + thisCursorIndex);
     int textIndexOffset = 0;    // Text index offset to start drawing in the box
 
     // Cursor rectangle
@@ -2513,6 +2516,8 @@ int GuiTextBox(Rectangle bounds, char *text, int textSize, bool editMode)
         {
             state = STATE_PRESSED;
 
+            if (textBoxCursorIndex > textLength) textBoxCursorIndex = textLength;
+
             // If text does not fit in the textbox and current cursor position is out of bounds,
             // we add an index offset to text for drawing only what requires depending on cursor
             while (textWidth >= textBounds.width)
@@ -2525,12 +2530,9 @@ int GuiTextBox(Rectangle bounds, char *text, int textSize, bool editMode)
                 textWidth = GetTextWidth(text + textIndexOffset) - GetTextWidth(text + textBoxCursorIndex);
             }
 
-            int textLength = (int)strlen(text);     // Get current text length
             int codepoint = GetCharPressed();       // Get Unicode codepoint
             if (multiline && IsKeyPressed(KEY_ENTER)) codepoint = (int)'\n';
 
-            if (textBoxCursorIndex > textLength) textBoxCursorIndex = textLength;
-
             // Encode codepoint as UTF-8
             int codepointSize = 0;
             const char *charEncoded = CodepointToUTF8(codepoint, &codepointSize);
@@ -2572,6 +2574,7 @@ int GuiTextBox(Rectangle bounds, char *text, int textSize, bool editMode)
                     for (int i = textBoxCursorIndex; i < textLength; i++) text[i] = text[i + nextCodepointSize];
 
                     textLength -= codepointSize;
+                    if (textBoxCursorIndex > textLength) textBoxCursorIndex = textLength;
 
                     // Make sure text last character is EOL
                     text[textLength] = '\0';
@@ -2663,7 +2666,7 @@ int GuiTextBox(Rectangle bounds, char *text, int textSize, bool editMode)
                 if (GetMousePosition().x >= (textBounds.x + textEndWidth - glyphWidth/2))
                 {
                     mouseCursor.x = textBounds.x + textEndWidth;
-                    mouseCursorIndex = (int)strlen(text);
+                    mouseCursorIndex = textLength;
                 }
 
                 // Place cursor at required index on mouse click
@@ -2695,7 +2698,7 @@ int GuiTextBox(Rectangle bounds, char *text, int textSize, bool editMode)
 
                 if (IsMouseButtonPressed(MOUSE_LEFT_BUTTON))
                 {
-                    textBoxCursorIndex = (int)strlen(text);   // GLOBAL: Place cursor index to the end of current text
+                    textBoxCursorIndex = textLength;   // GLOBAL: Place cursor index to the end of current text
                     result = 1;
                 }
             }