OOLegacyScriptWhitelist.m

Go to the documentation of this file.

/*
 
OOLegacyScriptWhitelist.m
 
 
Oolite
Copyright (C) 2004-2013 Giles C Williams and contributors
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
 
*/
 
#import "OOCocoa.h"
#import "OOLegacyScriptWhitelist.h"
#import "OOStringParsing.h"
#import "ResourceManager.h"
#import "OOCollectionExtractors.h"
#import "PlayerEntityLegacyScriptEngine.h"
#import "NSDictionaryOOExtensions.h"
#import "OODeepCopy.h"
 
 
#define INCLUDE_RAW_STRING OOLITE_DEBUG // If nonzero, raw condition strings are included; if zero, a placeholder is used.
 
 
typedef struct SanStackElement SanStackElement;
struct SanStackElement
{
    SanStackElement     *back;
    NSString            *key;       // Dictionary key; nil for arrays.
    NSUInteger          index;      // Array index if key is nil.
};
 
 
static NSArray *OOSanitizeLegacyScriptInternal(NSArray *script, SanStackElement *stack, BOOL allowAIMethods);
static NSArray *OOSanitizeLegacyScriptConditionsInternal(NSArray *conditions, SanStackElement *stack);
 
static NSArray *SanitizeCondition(NSString *condition, SanStackElement *stack);
static NSArray *SanitizeConditionalStatement(NSDictionary *statement, SanStackElement *stack, BOOL allowAIMethods);
static NSArray *SanitizeActionStatement(NSString *statement, SanStackElement *stack, BOOL allowAIMethods);
static OOOperationType ClassifyLHSConditionSelector(NSString *selectorString, NSString **outSanitizedMethod, SanStackElement *stack);
static NSString *SanitizeQueryMethod(NSString *selectorString);                         // Checks aliases and whitelist, returns nil if whitelist fails.
static NSString *SanitizeActionMethod(NSString *selectorString, BOOL allowAIMethods);   // Checks aliases and whitelist, returns nil if whitelist fails.
static NSArray *AlwaysFalseConditions(void);
static BOOL IsAlwaysFalseConditions(NSArray *conditions);
 
static NSString *StringFromStack(SanStackElement *topOfStack);
 
 
NSArray *OOSanitizeLegacyScript(NSArray *script, NSString *context, BOOL allowAIMethods)
{
    SanStackElement stackRoot = { NULL, context, 0 };
    NSArray *result = OOSanitizeLegacyScriptInternal(script, &stackRoot, allowAIMethods);
    return [OODeepCopy(result) autorelease];
}
 
 
static NSArray *OOSanitizeLegacyScriptInternal(NSArray *script, SanStackElement *stack, BOOL allowAIMethods)
{
    NSAutoreleasePool           *pool = nil;
    NSMutableArray              *result = nil;
    id                          statement = nil;
    NSUInteger                  index = 0;
    
    pool = [[NSAutoreleasePool alloc] init];
    
    result = [NSMutableArray arrayWithCapacity:[script count]];
    
    foreach (statement, script)
    {
        SanStackElement subStack =
        {
            stack, nil, index++
        };
        
        if ([statement isKindOfClass:[NSDictionary class]])
        {
            statement = SanitizeConditionalStatement(statement, &subStack, allowAIMethods);
        }
        else if ([statement isKindOfClass:[NSString class]])
        {
            statement = SanitizeActionStatement(statement, &subStack, allowAIMethods);
        }
        else
        {
            OOLog(@"script.syntax.statement.invalidType", @"***** SCRIPT ERROR: in %@, statement is of invalid type - expected string or dictionary, got %@.", StringFromStack(stack), [statement class]);
            statement = nil;
        }
        
        if (statement != nil)
        {
            [result addObject:statement];
        }
    }
    
    [result retain];
    [pool release];
    
    return [result autorelease];
}
 
 
NSArray *OOSanitizeLegacyScriptConditions(NSArray *conditions, NSString *context)
{
    if (context == nil)  context = @"<anonymous conditions>";
    SanStackElement stackRoot = { NULL, context, 0 };
    NSArray *result = OOSanitizeLegacyScriptConditionsInternal(conditions, &stackRoot);
    return [OODeepCopy(result) autorelease];
}
 
 
static NSArray *OOSanitizeLegacyScriptConditionsInternal(NSArray *conditions, SanStackElement *stack)
{
    NSString                    *condition = nil;
    NSMutableArray              *result = nil;
    NSArray                     *tokens = nil;
    BOOL                        OK = YES;
    NSUInteger                  index = 0;
    
    if (OOLegacyConditionsAreSanitized(conditions) || conditions == nil)  return conditions;
    
    result = [NSMutableArray arrayWithCapacity:[conditions count]];
    
    foreach (condition, conditions)
    {
        SanStackElement subStack =
        {
            stack, nil, index++
        };
        
        if (![condition isKindOfClass:[NSString class]])
        {
            OOLog(@"script.syntax.condition.notString", @"***** SCRIPT ERROR: in %@, bad condition - expected string, got %@; ignoring.", StringFromStack(stack), [condition class]);
            OK = NO;
            break;
        }
        
        tokens = SanitizeCondition(condition, &subStack);
        if (tokens != nil)
        {
            [result addObject:tokens];
        }
        else
        {
            OK = NO;
            break;
        }
    }
    
    if (OK)  return result;
    else  return AlwaysFalseConditions();
}
 
 
BOOL OOLegacyConditionsAreSanitized(NSArray *conditions)
{
    if ([conditions count] == 0)  return YES;   // Empty array is safe.
    return [[conditions objectAtIndex:0] isKindOfClass:[NSArray class]];
}
 
 
static NSArray *SanitizeCondition(NSString *condition, SanStackElement *stack)
{
    NSArray                     *tokens = nil;
    NSUInteger                  i, tokenCount;
    OOOperationType             opType;
    NSString                    *selectorString = nil;
    NSString                    *sanitizedSelectorString = nil;
    NSString                    *comparatorString = nil;
    OOComparisonType            comparatorValue;
    NSMutableArray              *rhs = nil;
    NSString                    *rhsItem = nil;
    NSString                    *rhsSelector = nil;
    NSArray                     *sanitizedRHSItem = nil;
    NSString                    *stringSegment = nil;
    
    tokens = ScanTokensFromString(condition);
    tokenCount = [tokens count];
    
    if (tokenCount < 1)
    {
        OOLog(@"script.debug.syntax.scriptCondition.noneSpecified", @"***** SCRIPT ERROR: in %@, empty script condition.", StringFromStack(stack));
        return nil;
    }
    
    // Parse left-hand side.
    selectorString = [tokens oo_stringAtIndex:0];
    opType = ClassifyLHSConditionSelector(selectorString, &sanitizedSelectorString, stack);
    if (opType >= OP_INVALID)
    {
        OOLog(@"script.unpermittedMethod", @"***** SCRIPT ERROR: in %@ (\"%@\"), method \"%@\" not allowed.", StringFromStack(stack), condition, selectorString);
        return nil;
    }
    
    // Parse operator.
    if (tokenCount > 1)
    {
        comparatorString = [tokens oo_stringAtIndex:1];
        if ([comparatorString isEqualToString:@"equal"])  comparatorValue = COMPARISON_EQUAL;
        else if ([comparatorString isEqualToString:@"notequal"])  comparatorValue = COMPARISON_NOTEQUAL;
        else if ([comparatorString isEqualToString:@"lessthan"])  comparatorValue = COMPARISON_LESSTHAN;
        else if ([comparatorString isEqualToString:@"greaterthan"])  comparatorValue = COMPARISON_GREATERTHAN;
        else if ([comparatorString isEqualToString:@"morethan"])  comparatorValue = COMPARISON_GREATERTHAN;
        else if ([comparatorString isEqualToString:@"oneof"])  comparatorValue = COMPARISON_ONEOF;
        else if ([comparatorString isEqualToString:@"undefined"])  comparatorValue = COMPARISON_UNDEFINED;
        else
        {
            OOLog(@"script.debug.syntax.badComparison", @"***** SCRIPT ERROR: in %@ (\"%@\"), unknown comparison operator \"%@\", will return NO.", StringFromStack(stack), condition, comparatorString);
            return nil;
        }
    }
    else
    {
        /*  In the direct interpreter, having no operator resulted in an
            implicit COMPARISON_NO operator, which always evaluated to false.
            Returning NO here causes AlwaysFalseConditions() to be used, which
            has the same effect.
         */
        OOLog(@"script.debug.syntax.noOperator", @"----- WARNING: SCRIPT in %@ -- No operator in expression \"%@\", will always evaluate as false.", StringFromStack(stack), condition);
        return nil;
    }
    
    // Check for invalid opType/comparator combinations.
    if (opType == OP_NUMBER && comparatorValue == COMPARISON_UNDEFINED)
    {
        OOLog(@"script.debug.syntax.invalidOperator", @"***** SCRIPT ERROR: in %@ (\"%@\"), comparison operator \"%@\" is not valid for %@.", StringFromStack(stack), condition, @"undefined", @"numbers");
        return nil;
    }
    else if (opType == OP_BOOL)
    {
        switch (comparatorValue)
        {
            // Valid comparators
            case COMPARISON_EQUAL:
            case COMPARISON_NOTEQUAL:
                break;
            
            default:
                OOLog(@"script.debug.syntax.invalidOperator", @"***** SCRIPT ERROR: in %@ (\"%@\"), comparison operator \"%@\" is not valid for %@.", StringFromStack(stack), condition, OOComparisonTypeToString(comparatorValue), @"booleans");
                return nil;
                
        }
    }
    
    /*  Parse right-hand side. Each token is converted to an array of the
        token and a boolean indicating whether it's a selector.
        
        This also coalesces non-selector tokens, i.e. whitespace-separated
        string segments.
    */
    if (tokenCount > 2)
    {
        rhs = [NSMutableArray arrayWithCapacity:tokenCount - 2];
        for (i = 2; i < tokenCount; i++)
        {
            rhsItem = [tokens oo_stringAtIndex:i];
            rhsSelector = SanitizeQueryMethod(rhsItem);
            if (rhsSelector != nil)
            {
                // Method
                if (stringSegment != nil)
                {
                    // Add stringSegment as a literal token.
                    sanitizedRHSItem = [NSArray arrayWithObjects:[NSNumber numberWithBool:NO], stringSegment, nil];
                    [rhs addObject:sanitizedRHSItem];
                    stringSegment = nil;
                }
                
                sanitizedRHSItem = [NSArray arrayWithObjects:[NSNumber numberWithBool:YES], rhsSelector, nil];
                [rhs addObject:sanitizedRHSItem];
            }
            else
            {
                // String; append to stringSegment
                if (stringSegment == nil)  stringSegment = rhsItem;
                else  stringSegment = [NSString stringWithFormat:@"%@ %@", stringSegment, rhsItem];
            }
        }
        
        if (stringSegment != nil)
        {
            sanitizedRHSItem = [NSArray arrayWithObjects:[NSNumber numberWithBool:NO], stringSegment, nil];
            [rhs addObject:sanitizedRHSItem];
        }
    }
    else
    {
        rhs = [NSMutableArray array];
    }
    
    NSString *rawString = nil;
#if INCLUDE_RAW_STRING
    rawString = condition;
#else
    rawString = @"<condition>";
#endif
    
    return [NSArray arrayWithObjects:
            [NSNumber numberWithUnsignedInt:opType],
            rawString,
            sanitizedSelectorString,
            [NSNumber numberWithUnsignedInt:comparatorValue],
            rhs,
            nil];
}
 
 
static NSArray *SanitizeConditionalStatement(NSDictionary *statement, SanStackElement *stack, BOOL allowAIMethods)
{
    NSArray                 *conditions = nil;
    NSArray                 *doActions = nil;
    NSArray                 *elseActions = nil;
    
    conditions = [statement oo_arrayForKey:@"conditions"];
    if (conditions == nil)
    {
        OOLog(@"script.syntax.noConditions", @"***** SCRIPT ERROR: in %@, conditions array contains no \"conditions\" entry, ignoring.", StringFromStack(stack));
        return nil;
    }
    
    // Sanitize conditions.
    SanStackElement subStack = { stack, @"conditions", 0 };
    conditions = OOSanitizeLegacyScriptConditionsInternal(conditions, &subStack);
    if (conditions == nil)
    {
        return nil;
    }
    
    // Sanitize do and else.
    if (!IsAlwaysFalseConditions(conditions))  doActions = [statement oo_arrayForKey:@"do"];
    if (doActions != nil)
    {
        subStack.key = @"do";
        doActions = OOSanitizeLegacyScriptInternal(doActions, &subStack, allowAIMethods);
    }
    
    elseActions = [statement oo_arrayForKey:@"else"];
    if (elseActions != nil)
    {
        subStack.key = @"else";
        elseActions = OOSanitizeLegacyScriptInternal(elseActions, &subStack, allowAIMethods);
    }
    
    // If neither does anything, the statment has no effect.
    if ([doActions count] == 0 && [elseActions count] == 0)
    {
        return nil;
    }
    
    if (doActions == nil)  doActions = [NSArray array];
    if (elseActions == nil)  elseActions = [NSArray array];
    
    return [NSArray arrayWithObjects:[NSNumber numberWithBool:YES], conditions, doActions, elseActions, nil];
}
 
 
static NSArray *SanitizeActionStatement(NSString *statement, SanStackElement *stack, BOOL allowAIMethods)
{
    NSMutableArray              *tokens = nil;
    NSUInteger                  tokenCount;
    NSString                    *rawSelectorString = nil;
    NSString                    *selectorString = nil;
    NSString                    *argument = nil;
    
    tokens = ScanTokensFromString(statement);
    tokenCount = [tokens count];
    if (tokenCount == 0)  return nil;
    
    rawSelectorString = [tokens objectAtIndex:0];
    selectorString = SanitizeActionMethod(rawSelectorString, allowAIMethods);
    if (selectorString == nil)
    {
        OOLog(@"script.unpermittedMethod", @"***** SCRIPT ERROR: in %@ (\"%@\"), method \"%@\" not allowed.", StringFromStack(stack), statement, rawSelectorString);
        return nil;
    }
    
    if ([selectorString isEqualToString:@"doNothing"])
    {
        return nil;
    }
    
    if ([selectorString hasSuffix:@":"])
    {
        // Expects an argument
        if (tokenCount == 2)
        {
            argument = [tokens objectAtIndex:1];
        }
        else
        {
            [tokens removeObjectAtIndex:0];
            argument = [tokens componentsJoinedByString:@" "];
        }
        
        argument = [argument stringByReplacingOccurrencesOfString:@"[credits_number]" withString:@"[_oo_legacy_credits_number]"];
    }
    
    return [NSArray arrayWithObjects:[NSNumber numberWithBool:NO], selectorString, argument, nil];
}
 
 
static OOOperationType ClassifyLHSConditionSelector(NSString *selectorString, NSString **outSanitizedSelector, SanStackElement *stack)
{
    assert(outSanitizedSelector != NULL);
    
    *outSanitizedSelector = selectorString;
    
    // Allow arbitrary mission_foo or local_foo pseudo-selectors.
    if ([selectorString hasPrefix:@"mission_"])  return OP_MISSION_VAR;
    if ([selectorString hasPrefix:@"local_"])  return OP_LOCAL_VAR;
    
    // If it's a real method, check against whitelist.
    *outSanitizedSelector = SanitizeQueryMethod(selectorString);
    if (*outSanitizedSelector == nil)
    {
        return OP_INVALID;
    }
    
    // If it's a real method, and in the whitelist, classify by suffix.
    if ([selectorString hasSuffix:@"_string"])  return OP_STRING;
    if ([selectorString hasSuffix:@"_number"])  return OP_NUMBER;
    if ([selectorString hasSuffix:@"_bool"])  return OP_BOOL;
    
    // If we got here, something's wrong.
    OOLog(@"script.sanitize.unclassifiedSelector", @"***** ERROR: Whitelisted query method \"%@\" has no type suffix, treating as invalid.", selectorString);
    return OP_INVALID;
}
 
 
static NSString *SanitizeQueryMethod(NSString *selectorString)
{
    static NSSet                *whitelist = nil;
    static NSDictionary         *aliases = nil;
    NSString                    *aliasedSelector = nil;
    
    if (whitelist == nil)
    {
        whitelist = [[NSSet alloc] initWithArray:[[ResourceManager whitelistDictionary] oo_arrayForKey:@"query_methods"]];
        aliases = [[[ResourceManager whitelistDictionary] oo_dictionaryForKey:@"query_method_aliases"] retain];
    }
    
    aliasedSelector = [aliases oo_stringForKey:selectorString];
    if (aliasedSelector != nil)  selectorString = aliasedSelector;
    
    if (![whitelist containsObject:selectorString])  selectorString = nil;
    
    return selectorString;
}
 
 
static NSString *SanitizeActionMethod(NSString *selectorString, BOOL allowAIMethods)
{
    static NSSet                *whitelist = nil;
    static NSSet                *whitelistWithAI = nil;
    static NSDictionary         *aliases = nil;
    static NSDictionary         *aliasesWithAI = nil;
    NSString                    *aliasedSelector = nil;
    
    if (whitelist == nil)
    {
        NSArray                     *actionMethods = nil;
        NSArray                     *aiMethods = nil;
        NSArray                     *aiAndActionMethods = nil;
        
        actionMethods = [[ResourceManager whitelistDictionary] oo_arrayForKey:@"action_methods"];
        aiMethods = [[ResourceManager whitelistDictionary] oo_arrayForKey:@"ai_methods"];
        aiAndActionMethods = [[ResourceManager whitelistDictionary] oo_arrayForKey:@"ai_and_action_methods"];
        
        if (actionMethods == nil)  actionMethods = [NSArray array];
        if (aiMethods == nil)  aiMethods = [NSArray array];
        
        if (aiAndActionMethods != nil)  actionMethods = [actionMethods arrayByAddingObjectsFromArray:aiAndActionMethods];
        
        whitelist = [[NSSet alloc] initWithArray:actionMethods];
        whitelistWithAI = [[NSSet alloc] initWithArray:[aiMethods arrayByAddingObjectsFromArray:actionMethods]];
        
        aliases = [[[ResourceManager whitelistDictionary] oo_dictionaryForKey:@"action_method_aliases"] retain];
        
        aliasesWithAI = [[ResourceManager whitelistDictionary] oo_dictionaryForKey:@"ai_method_aliases"];
        if (aliasesWithAI != nil)
        {
            aliasesWithAI = [[aliasesWithAI dictionaryByAddingEntriesFromDictionary:aliases] copy];
        }
        else
        {
            aliasesWithAI = [aliases copy];
        }
    }
    
    aliasedSelector = [(allowAIMethods ? aliasesWithAI : aliases) oo_stringForKey:selectorString];
    if (aliasedSelector != nil)  selectorString = aliasedSelector;
    
    if (![(allowAIMethods ? whitelistWithAI : whitelist) containsObject:selectorString])  selectorString = nil;
    
    return selectorString;
}
 
 
//  Return a conditions array that always evaluates as false.
static NSArray *AlwaysFalseConditions(void)
{
    static NSArray *alwaysFalse = nil;
    if (alwaysFalse != nil)
    {
        alwaysFalse = [NSArray arrayWithObject:[NSArray arrayWithObject:[NSNumber numberWithUnsignedInt:OP_FALSE]]];
        [alwaysFalse retain];
    }
    
    return alwaysFalse;
}
 
 
static BOOL IsAlwaysFalseConditions(NSArray *conditions)
{
    return [[conditions oo_arrayAtIndex:0] oo_unsignedIntAtIndex:0] == OP_FALSE;
}
 
 
static NSMutableString *StringFromStackInternal(SanStackElement *topOfStack)
{
    if (topOfStack == NULL)  return nil;
    
    NSMutableString *base = StringFromStackInternal(topOfStack->back);
    if (base == nil)  base = [NSMutableString string];
    
    NSString *string = topOfStack->key;
    if (string == nil)  string = [NSString stringWithFormat:@"%lu", (unsigned long)topOfStack->index];
    if ([base length] > 0)  [base appendString:@"."];
    
    [base appendString:string];
    
    return base;
}
 
 
static NSString *StringFromStack(SanStackElement *topOfStack)
{
    return StringFromStackInternal(topOfStack);
}