patch 8.0.0378: possible overflow when reading corrupted undo file

Problem:    Another possible overflow when reading corrupted undo file.
Solution:   Check if allocated size is not too big. (King)

Author: brammool

src/undo.c

@@ -1385,7 +1385,7 @@ unserialize_uep(bufinfo_T *bi, int *error, char_u *file_name)
 {
     int		i;
     u_entry_T	*uep;
-    char_u	**array;
+    char_u	**array = NULL;
     char_u	*line;
     int		line_len;
 
@@ -1402,16 +1402,15 @@ unserialize_uep(bufinfo_T *bi, int *error, char_u *file_name)
     uep->ue_size = undo_read_4c(bi);
     if (uep->ue_size > 0)
     {
-	array = (char_u **)U_ALLOC_LINE(sizeof(char_u *) * uep->ue_size);
+	if (uep->ue_size < LONG_MAX / (int)sizeof(char_u *))
+	    array = (char_u **)U_ALLOC_LINE(sizeof(char_u *) * uep->ue_size);
 	if (array == NULL)
 	{
 	    *error = TRUE;
 	    return uep;
 	}
 	vim_memset(array, 0, sizeof(char_u *) * uep->ue_size);
     }
-    else
-	array = NULL;
     uep->ue_array = array;
 
     for (i = 0; i < uep->ue_size; ++i)

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    378,
 /**/
     377,
 /**/