richedit: Add bounds checks for EM_GETTEXTRANGE with tests.

Wine was not doing bounds checks for EM_GETTEXTRANGE, which was causing a crash in Bug 17822. The added tests would cause a crash without the added bounds checks in the richedit code. The bounds checks I put in HandleMessage, since ME_GetTextRange is also called for ME_GETSELTEXT which should not have bounds checks, since it uses the selection range. When the ME_GETTEXTRANGE message returns 0, no text is copied, not even the NULL terminating charter. This differs from EM_GETSELTEXT which will copy the NULL terminating character when no text is selected. This behaviour is consistent with native richedit controls.

richedit: Add bounds checks for EM_GETTEXTRANGE with tests.
caca4860 · Dylan Smith · Alexandre Julliard · 4544efc9 · caca4860 · caca4860
Commit caca4860 authored Mar 23, 2009 by Dylan Smith Committed by Alexandre Julliard Mar 23, 2009
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Showing with 58 additions and 18 deletions

editor.c dlls/riched20/editor.c +18 -18

editor.c dlls/riched20/tests/editor.c +40 -0

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--- a/dlls/riched20/editor.c
+++ b/dlls/riched20/editor.c
@@ -1906,20 +1906,16 @@ static int ME_GetTextEx(ME_TextEditor *editor, GETTEXTEX *ex, LPARAM pText)
    }
 }

-static int ME_GetTextRange(ME_TextEditor *editor, TEXTRANGEW *rng, BOOL unicode)
+static int ME_GetTextRange(ME_TextEditor *editor, WCHAR *strText,
+                           int start, int nLen, BOOL unicode)
 {
-    if (unicode)
-      return ME_GetTextW(editor, rng->lpstrText, rng->chrg.cpMin,
-                         rng->chrg.cpMax-rng->chrg.cpMin, 0);
-    else
-    {
-      int nLen = rng->chrg.cpMax-rng->chrg.cpMin;
+    if (unicode) {
+      return ME_GetTextW(editor, strText, start, nLen, 0);
+    } else {
      WCHAR *p = ALLOC_N_OBJ(WCHAR, nLen+1);
-      int nChars = ME_GetTextW(editor, p, rng->chrg.cpMin, nLen, 0);
-      /* FIXME this is a potential security hole (buffer overrun)
-         if you know more about wchar->mbyte conversion please explain
-      */
-      WideCharToMultiByte(CP_ACP, 0, p, nChars+1, (char *)rng->lpstrText, nLen+1, NULL, NULL);
+      int nChars = ME_GetTextW(editor, p, start, nLen, 0);
+      WideCharToMultiByte(CP_ACP, 0, p, nChars+1, (char *)strText,
+                          nLen+1, NULL, NULL);
      FREE_OBJ(p);
      return nChars;
    }
@@ -3580,12 +3576,9 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
  case EM_GETSELTEXT:
  {
    int from, to;
-    TEXTRANGEW tr; /* W and A differ only by rng->lpstrText */
    ME_GetSelection(editor, &from, &to);
-    tr.chrg.cpMin = from;
-    tr.chrg.cpMax = to;
-    tr.lpstrText = (WCHAR *)lParam;
-    return ME_GetTextRange(editor, &tr, unicode);
+    return ME_GetTextRange(editor, (WCHAR *)lParam, from,
+                           to - from, unicode);
  }
  case EM_GETSCROLLPOS:
  {
@@ -3597,10 +3590,17 @@ LRESULT ME_HandleMessage(ME_TextEditor *editor, UINT msg, WPARAM wParam,
  case EM_GETTEXTRANGE:
  {
    TEXTRANGEW *rng = (TEXTRANGEW *)lParam;
+    int start = rng->chrg.cpMin;
+    int end = rng->chrg.cpMax;
+    int textlength = ME_GetTextLength(editor);
    TRACE("EM_GETTEXTRANGE min=%d max=%d unicode=%d emul1.0=%d length=%d\n",
      rng->chrg.cpMin, rng->chrg.cpMax, unicode,
      editor->bEmulateVersion10, ME_GetTextLength(editor));
-    return ME_GetTextRange(editor, rng, unicode);
+    if (start < 0) return 0;
+    if ((start == 0 && end == -1) || end > textlength)
+      end = textlength;
+    if (start >= end) return 0;
+    return ME_GetTextRange(editor, rng->lpstrText, start, end - start, unicode);
  }
  case EM_GETLINE:
  {

--- a/dlls/riched20/tests/editor.c
+++ b/dlls/riched20/tests/editor.c
@@ -1420,6 +1420,46 @@ static void test_EM_GETTEXTRANGE(void)
    ok(result == 7, "EM_GETTEXTRANGE returned %ld\n", result);
    ok(!strcmp(expect, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);

+    /* cpMax of text length is used instead of -1 in this case */
+    textRange.lpstrText = buffer;
+    textRange.chrg.cpMin = 0;
+    textRange.chrg.cpMax = -1;
+    result = SendMessage(hwndRichEdit, EM_GETTEXTRANGE, 0, (LPARAM)&textRange);
+    ok(result == strlen(text2), "EM_GETTEXTRANGE returned %ld\n", result);
+    ok(!strcmp(text2, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
+
+    /* cpMin < 0 causes no text to be copied, and 0 to be returned */
+    textRange.lpstrText = buffer;
+    textRange.chrg.cpMin = -1;
+    textRange.chrg.cpMax = 1;
+    result = SendMessage(hwndRichEdit, EM_GETTEXTRANGE, 0, (LPARAM)&textRange);
+    ok(result == 0, "EM_GETTEXTRANGE returned %ld\n", result);
+    ok(!strcmp(text2, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
+
+    /* cpMax of -1 is not replaced with text length if cpMin != 0 */
+    textRange.lpstrText = buffer;
+    textRange.chrg.cpMin = 1;
+    textRange.chrg.cpMax = -1;
+    result = SendMessage(hwndRichEdit, EM_GETTEXTRANGE, 0, (LPARAM)&textRange);
+    ok(result == 0, "EM_GETTEXTRANGE returned %ld\n", result);
+    ok(!strcmp(text2, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
+
+    /* no end character is copied if cpMax - cpMin < 0 */
+    textRange.lpstrText = buffer;
+    textRange.chrg.cpMin = 5;
+    textRange.chrg.cpMax = 5;
+    result = SendMessage(hwndRichEdit, EM_GETTEXTRANGE, 0, (LPARAM)&textRange);
+    ok(result == 0, "EM_GETTEXTRANGE returned %ld\n", result);
+    ok(!strcmp(text2, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
+
+    /* cpMax of text length is used if cpMax > text length*/
+    textRange.lpstrText = buffer;
+    textRange.chrg.cpMin = 0;
+    textRange.chrg.cpMax = 1000;
+    result = SendMessage(hwndRichEdit, EM_GETTEXTRANGE, 0, (LPARAM)&textRange);
+    ok(result == strlen(text2), "EM_GETTEXTRANGE returned %ld\n", result);
+    ok(!strcmp(text2, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
+
    DestroyWindow(hwndRichEdit);
 }