Add more configuration parameter lower-bound checks.

blackbox.c

@@ -198,6 +198,8 @@ static const char *validate_params(const game_params *params, bool full)
         return "Widths and heights greater than 255 are not supported";
     if (params->minballs < 0)
         return "Negative number of balls";
+    if (params->minballs < 1)
+        return "Number of balls must be at least one";
     if (params->minballs > params->maxballs)
         return "Minimum number of balls may not be greater than maximum";
     if (params->minballs >= params->w * params->h)

flood.c

@@ -212,7 +212,7 @@ static game_params *custom_params(const config_item *cfg)
 
 static const char *validate_params(const game_params *params, bool full)
 {
-    if (params->w < 2 && params->h < 2)
+    if (params->w * params->h < 2)
         return "Grid must contain at least two squares";
     if (params->w < 1 || params->h < 1)
         return "Width and height must be at least one";

mines.c

@@ -279,6 +279,8 @@ static const char *validate_params(const game_params *params, bool full)
         return "Width times height must not be unreasonably large";
     if (params->n < 0)
 	return "Mine count may not be negative";
+    if (params->n < 1)
+        return "Number of mines must be greater than zero";
     if (params->n > params->w * params->h - 9)
 	return "Too many mines for grid size";
 

netslide.c

@@ -318,6 +318,8 @@ static const char *validate_params(const game_params *params, bool full)
 	return "Barrier probability may not be negative";
     if (params->barrier_probability > 1)
 	return "Barrier probability may not be greater than 1";
+    if (params->movetarget < 0)
+        return "Number of shuffling moves may not be negative";
     return NULL;
 }
 

pattern.c

@@ -185,6 +185,8 @@ static const char *validate_params(const game_params *params, bool full)
     if (params->w > INT_MAX - 1 || params->h > INT_MAX - 1 ||
         params->w > INT_MAX / params->h)
         return "Puzzle must not be unreasonably large";
+    if (params->w * params->h < 2)
+        return "Grid must contain at least two squares";
     return NULL;
 }
 

sixteen.c

@@ -180,7 +180,8 @@ static const char *validate_params(const game_params *params, bool full)
 	return "Width and height must both be at least two";
     if (params->w > INT_MAX / params->h)
         return "Width times height must not be unreasonably large";
-
+    if (params->movetarget < 0)
+        return "Number of shuffling moves may not be negative";
     return NULL;
 }
 

twiddle.c

@@ -219,6 +219,8 @@ static const char *validate_params(const game_params *params, bool full)
 	return "Height must be at least the rotating block size";
     if (params->w > INT_MAX / params->h)
         return "Width times height must not be unreasonably large";
+    if (params->movetarget < 0)
+        return "Number of shuffling moves may not be negative";
     return NULL;
 }