Fixing a rare issue where a pointer of a already freed unit would have corrupted memory and causing unexpected behavior (most likely crashing)

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@16803 54d463be-8e91-2dee-dedb-b68131a5f0ec

src/map/battle.c

@@ -69,7 +69,7 @@ static int battle_gettargeted_sub(struct block_list *bl, va_list ap)
 
 	if (bl->id == target_id)
 		return 0;
-	if (*c >= 24)
+	if (*c >= 23)
 		return 0;
 
 	ud = unit_bl2ud(bl);
@@ -90,7 +90,7 @@ struct block_list* battle_gettargeted(struct block_list *target)
 
 	memset(bl_list, 0, sizeof(bl_list));
 	map_foreachinrange(battle_gettargeted_sub, target, AREA_SIZE, BL_CHAR, bl_list, &c, target->id);
-	if (c == 0 || c > 24)
+	if (c == 0 || c > 23)
 		return NULL;
 	return bl_list[rnd()%c];
 }
@@ -187,8 +187,8 @@ struct block_list* battle_getenemyarea(struct block_list *src, int x, int y, int
 
 // ƒ_??[ƒW‚Ì’x‰„
 struct delay_damage {
-	struct block_list *src;
-	struct block_list *target;
+	int src_id;
+	int target_id;
 	int damage;
 	int delay;
 	unsigned short distance;
@@ -198,29 +198,37 @@ struct delay_damage {
 	unsigned short attack_type;
 };
 
-int battle_delay_damage_sub(int tid, unsigned int tick, int id, intptr_t data)
-{
+int battle_delay_damage_sub(int tid, unsigned int tick, int id, intptr_t data) {
 	struct delay_damage *dat = (struct delay_damage *)data;
-
-	if ( dat && dat->target && dat->target->prev != NULL && !status_isdead(dat->target) ) { 
-		if( dat->src && dat->src->prev != NULL && id == dat->src->id &&
-			dat->target->m == dat->src->m &&
-			(dat->target->type != BL_PC || ((TBL_PC*)dat->target)->invincible_timer == INVALID_TIMER) &&
-			check_distance_bl(dat->src, dat->target, dat->distance) ) //Check to see if you haven't teleported. [Skotlex]
+	
+	if ( dat ) {
+		struct block_list* src;
+		struct block_list* target = map_id2bl(dat->target_id);
+		
+		if( !target || status_isdead(target) ) {/* nothing we can do */
+			ers_free(delay_damage_ers, dat);
+			return 0;
+		}
+			
+		src = map_id2bl(dat->src_id);
+		
+		if( src && target && target->m == src->m &&
+			(target->type != BL_PC || ((TBL_PC*)target)->invincible_timer == INVALID_TIMER) &&
+			check_distance_bl(src, target, dat->distance) ) //Check to see if you haven't teleported. [Skotlex]
 		{
 			map_freeblock_lock();
-			status_fix_damage(dat->src, dat->target, dat->damage, dat->delay);
-			if( dat->attack_type && !status_isdead(dat->target) )
-				skill_additional_effect(dat->src,dat->target,dat->skill_id,dat->skill_lv,dat->attack_type,dat->dmg_lv,tick);
+			status_fix_damage(src, target, dat->damage, dat->delay);
+			if( dat->attack_type && !status_isdead(target) )
+				skill_additional_effect(src,target,dat->skill_id,dat->skill_lv,dat->attack_type,dat->dmg_lv,tick);
 			if( dat->dmg_lv > ATK_BLOCK && dat->attack_type )
-				skill_counter_additional_effect(dat->src,dat->target,dat->skill_id,dat->skill_lv,dat->attack_type,tick);
+				skill_counter_additional_effect(src,target,dat->skill_id,dat->skill_lv,dat->attack_type,tick);
 			map_freeblock_unlock();
-		} else if( dat->skill_id == CR_REFLECTSHIELD && !map_id2bl(id) ) {
+		} else if( target && !src && dat->skill_id == CR_REFLECTSHIELD ) {
 			/**
 			 * it was monster reflected damage, and the monster died, we pass the damage to the character as expected
 			 **/
 			map_freeblock_lock();
-			status_fix_damage(dat->target, dat->target, dat->damage, dat->delay);
+			status_fix_damage(target, target, dat->damage, dat->delay);
 			map_freeblock_unlock();
 		}
 	}
@@ -251,8 +259,8 @@ int battle_delay_damage (unsigned int tick, int amotion, struct block_list *src,
 		return 0;
 	}
 	dat = ers_alloc(delay_damage_ers, struct delay_damage);
-	dat->src = src;
-	dat->target = target;
+	dat->src_id = src->id;
+	dat->target_id = target->id;
 	dat->skill_id = skill_id;
 	dat->skill_lv = skill_lv;
 	dat->attack_type = attack_type;
@@ -263,7 +271,7 @@ int battle_delay_damage (unsigned int tick, int amotion, struct block_list *src,
 	if (src->type != BL_PC && amotion > 1000)
 		amotion = 1000; //Aegis places a damage-delay cap of 1 sec to non player attacks. [Skotlex]
 
-	add_timer(tick+amotion, battle_delay_damage_sub, src->id, (intptr_t)dat);
+	add_timer(tick+amotion, battle_delay_damage_sub, 0, (intptr_t)dat);
 	
 	return 0;
 }