Roman Pišl : user32/edit: Avoid division by zero during initialization.

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: e1cac281d94b6a87d079026fd8b4f07c0f8a25b5
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=e1cac281d94b6a87d079026fd...

Author: Roman Pišl 
Date:   Mon Apr 20 12:20:13 2020 +0200

user32/edit: Avoid division by zero during initialization.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=19239
Signed-off-by: Roman Pišl 
Signed-off-by: Nikolay Sivov 
Signed-off-by: Alexandre Julliard 
(cherry picked from commit d5e591d3cb55530cab33e5f6114b1519ec286d15)
Signed-off-by: Michael Stefaniuc

---

dlls/user32/edit.c       |  4 +--
 dlls/user32/tests/edit.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/dlls/user32/edit.c b/dlls/user32/edit.c
index 557a091c0d..aba6a084a2 100644
--- a/dlls/user32/edit.c
+++ b/dlls/user32/edit.c
@@ -465,7 +465,7 @@ static SCRIPT_STRING_ANALYSIS EDIT_UpdateUniscribeData(EDITSTATE *es, HDC dc, IN

static inline INT get_vertical_line_count(EDITSTATE *es)
 {
-	INT vlc = (es->format_rect.bottom - es->format_rect.top) / es->line_height;
+	INT vlc = es->line_height ? (es->format_rect.bottom - es->format_rect.top) / es->line_height : 0;
    return max(1,vlc);
 }

@@ -1638,7 +1638,7 @@ static void EDIT_UpdateScrollInfo(EDITSTATE *es)
    si.fMask	= SIF_PAGE | SIF_POS | SIF_RANGE | SIF_DISABLENOSCROLL;
    si.nMin		= 0;
    si.nMax		= es->line_count - 1;
-	si.nPage	= (es->format_rect.bottom - es->format_rect.top) / es->line_height;
+	si.nPage	= es->line_height ? (es->format_rect.bottom - es->format_rect.top) / es->line_height : 0;
    si.nPos		= es->y_offset;
    TRACE("SB_VERT, nMin=%d, nMax=%d, nPage=%d, nPos=%d\n",
    	si.nMin, si.nMax, si.nPage, si.nPos);
diff --git a/dlls/user32/tests/edit.c b/dlls/user32/tests/edit.c
index e3ed3341d6..2289bbf03f 100644
--- a/dlls/user32/tests/edit.c
+++ b/dlls/user32/tests/edit.c
@@ -1743,6 +1743,71 @@ static BOOL is_font_installed(const char*name)
     return ret;
 }

+static WNDPROC orig_class_proc;
+
+static LRESULT CALLBACK test_class_proc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
+{
+    RECT rect;
+    LRESULT result, r;
+
+    switch (message)
+    {
+        case WM_NCCREATE:
+            result = CallWindowProcA(orig_class_proc, hwnd, message, wParam, lParam);
+
+            memset(&rect, 0, sizeof(rect));
+            SendMessageA(hwnd, EM_GETRECT, 0, (LPARAM)&rect);
+            ok(!rect.right && !rect.bottom, "Invalid size after NCCREATE: %d x %d\n", rect.right, rect.bottom);
+
+            /* test that messages between WM_NCCREATE and WM_CREATE
+               don't crash or cause unexpected behavior */
+            r = SendMessageA(hwnd, EM_SETSEL, 0, 0);
+            ok(r == 1, "Returned %ld, expected 1.\n", r);
+            r = SendMessageA(hwnd, WM_SIZE, 0, 0x00100010);
+            todo_wine ok(r == 1, "Returned %ld, expected 1.\n", r);
+
+            return result;
+
+        case WM_CREATE:
+            /* test that messages between WM_NCCREATE and WM_CREATE
+               don't crash or cause unexpected behavior */
+            r = SendMessageA(hwnd, EM_SETSEL, 0, 0);
+            ok(r == 1, "Returned %ld, expected 1.\n", r);
+            r = SendMessageA(hwnd, WM_SIZE, 0, 0x00100010);
+            todo_wine ok(r == 1, "Returned %ld, expected 1.\n", r);
+
+            break;
+    }
+
+    return CallWindowProcA(orig_class_proc, hwnd, message, wParam, lParam);
+}
+
+static void test_initialization(void)
+{
+    BOOL ret;
+    ATOM atom;
+    HWND hwEdit;
+    WNDCLASSA cls;
+
+    ret = GetClassInfoA(NULL, "Edit", &cls);
+    ok(ret, "Failed to get class info.\n");
+
+    orig_class_proc = cls.lpfnWndProc;
+    cls.lpfnWndProc = test_class_proc;
+    cls.lpszClassName = "TestClassName";
+
+    atom = RegisterClassA(&cls);
+    ok(atom != 0, "Failed to register class.\n");
+
+    hwEdit = CreateWindowExA(0, (LPCSTR)MAKEINTATOM(atom), "Text Text",
+        ES_MULTILINE | WS_BORDER | ES_AUTOHSCROLL | ES_AUTOVSCROLL | WS_VSCROLL,
+        10, 10, 300, 300, NULL, NULL, hinst, NULL);
+    ok(hwEdit != NULL, "Failed to create a window.\n");
+
+    DestroyWindow(hwEdit);
+    UnregisterClassA((LPCSTR)MAKEINTATOM(atom), hinst);
+}
+
 static void test_margins(void)
 {
     HWND hwEdit;
@@ -3268,6 +3333,7 @@ START_TEST(edit)
     test_edit_control_6();
     test_edit_control_limittext();
     test_edit_control_scroll();
+    test_initialization();
     test_margins();
     test_margins_font_change();
     test_text_position();