give: Fix integer overflows on silly third arguments

[empserver] / src / lib / commands / give.c

diff --git a/src/lib/commands/give.c b/src/lib/commands/give.c
index 6ed9d8cd94c0ba13ef84d073592d97d74f3c5c30..f4bf59f878b523906c3061f91a0a08c5f2ca5c0c 100644 (file)
--- a/src/lib/commands/give.c
+++ b/src/lib/commands/give.c
@@ -1,6 +1,6 @@
 /*
  *  Empire - A multi-player, client/server Internet based war game.
- *  Copyright (C) 1986-2012, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *  Copyright (C) 1986-2013, Dave Pare, Jeff Bailey, Thomas Ruschak,
  *                Ken Stevens, Steve McClure, Markus Armbruster
  *
  *  Empire is free software: you can redistribute it and/or modify
@@ -29,6 +29,7 @@
  *  Known contributors to this file:
  *     David Muir Sharnoff
  *     Steve McClure, 1997
+ *     Markus Armbruster, 2004-2013
  */
 
 #include <config.h>
@@ -62,13 +63,14 @@ give(void)
            return RET_SYN;
        if ((amt = atoi(p)) == 0)
            return RET_SYN;
-       check_sect_ok(&sect);
+       if (!check_sect_ok(&sect))
+           return RET_FAIL;
        n = sect.sct_item[ip->i_uid];
-       if (amt < 0 && -amt > n) {
+       if (amt < 0 && n + amt < 0)
            m = 0;
-       } else if (amt > 0 && amt + n > ITEM_MAX) {
+       else if (amt > 0 && n > ITEM_MAX - amt)
            m = ITEM_MAX;
-       } else
+       else
            m = n + amt;
        sect.sct_item[ip->i_uid] = m;
        putsect(&sect);