* scroll.c: Integer and memory overflow fixes.

[bpt/emacs.git] / src / keymap.c

diff --git a/src/keymap.c b/src/keymap.c
index d33af68..c968b14 100644 (file)
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -1403,7 +1403,7 @@ silly_event_symbol_error (Lisp_Object c)
    some systems, static gets macro-defined to be the empty string.
    Ickypoo.  */
 static Lisp_Object *cmm_modes = NULL, *cmm_maps = NULL;
-static int cmm_size = 0;
+static ptrdiff_t cmm_size = 0;
 
 /* Store a pointer to an array of the currently active minor modes in
    *modeptr, a pointer to an array of the keymaps of the currently
@@ -1423,10 +1423,10 @@ static int cmm_size = 0;
    loop.  Instead, we'll use realloc/malloc and silently truncate the
    list, let the key sequence be read, and hope some other piece of
    code signals the error.  */
-int
+ptrdiff_t
 current_minor_maps (Lisp_Object **modeptr, Lisp_Object **mapptr)
 {
-  int i = 0;
+  ptrdiff_t i = 0;
   int list_number = 0;
   Lisp_Object alist, assoc, var, val;
   Lisp_Object emulation_alists;
@@ -1469,9 +1469,16 @@ current_minor_maps (Lisp_Object **modeptr, Lisp_Object **mapptr)
 
            if (i >= cmm_size)
              {
-               int newsize, allocsize;
+               ptrdiff_t newsize, allocsize;
                Lisp_Object *newmodes, *newmaps;
 
+               /* Check for size calculation overflow.  Other code
+                  (e.g., read_key_sequence) adds 3 to the count
+                  later, so subtract 3 from the limit here.  */
+               if (min (PTRDIFF_MAX, SIZE_MAX) / (2 * sizeof *newmodes) - 3
+                   < cmm_size)
+                 break;
+
                newsize = cmm_size == 0 ? 30 : cmm_size * 2;
                allocsize = newsize * sizeof *newmodes;
 
@@ -3712,11 +3719,11 @@ the same way.  The "active" keymaps in each alist are used before
   Vemulation_mode_map_alists = Qnil;
 
   DEFVAR_LISP ("where-is-preferred-modifier", Vwhere_is_preferred_modifier,
-              doc: /* Preferred modifier to use for `where-is'.
+              doc: /* Preferred modifier key to use for `where-is'.
 When a single binding is requested, `where-is' will return one that
-uses this modifier if possible.  If nil, or if no such binding exists,
-bindings using keys without modifiers (or only with meta) will be
-preferred.  */);
+uses this modifier key if possible.  If nil, or if no such binding
+exists, bindings using keys without modifiers (or only with meta) will
+be preferred.  */);
   Vwhere_is_preferred_modifier = Qnil;
   where_is_preferred_modifier = 0;