Prevent tampering with PRNG parameters in save

[open-adventure.git] / saveresume.c

diff --git a/saveresume.c b/saveresume.c
index 4378324c3b3fd5bf00437587727563c4f953e496..c5d51816e3b664029fbf09c6eed7872811663798 100644 (file)
--- a/saveresume.c
+++ b/saveresume.c
@@ -134,18 +134,27 @@ bool is_valid(struct game_t valgame)
      *  valid: no states are outside minimal or maximal value
      */
 
-    /*  Bounds check for locations
-     */
+    /* Prevent division by zero */
+    if (valgame.abbnum == 0) {
+        return false;
+    }
+
+    /* Prevent RNG substitution. Why we are saving PRNG parameters? */
+
+    if (valgame.lcg_a != game.lcg_a || valgame.lcg_c != game.lcg_c || valgame.lcg_m != game.lcg_m) {
+        return false;
+    }
+
+    /*  Bounds check for locations */
     if ( valgame.chloc < -1  || valgame.chloc > NLOCATIONS  ||
-         valgame.chloc < -1  || valgame.chloc > NLOCATIONS  ||
+         valgame.chloc2 < -1  || valgame.chloc2 > NLOCATIONS  ||
          valgame.loc < -1    || valgame.loc > NLOCATIONS    ||
          valgame.newloc < -1 || valgame.newloc > NLOCATIONS ||
          valgame.oldloc < -1 || valgame.oldloc > NLOCATIONS ||
-         valgame.oldloc < -1 || valgame.oldloc > NLOCATIONS) {
+         valgame.oldlc2 < -1 || valgame.oldlc2 > NLOCATIONS) {
         return false;
     }
-    /*  Bounds check for location arrays
-     */
+    /*  Bounds check for location arrays */
     for (int i = 0; i <= NDWARVES; i++) {
         if (valgame.dloc[i]  < -1 || valgame.dloc[i]  > NLOCATIONS  ||
             valgame.odloc[i] < -1 || valgame.odloc[i] > NLOCATIONS) {