Tool/CryptorCommands.m

/*
    Copyright (C) 2016 Apple Inc. All Rights Reserved.
    See LICENSE.txt for this sample’s licensing information
    
    Abstract:
    Commands for symmetric encryption and decryption.
 */
 
#import "CryptorCommands.h"
 
#import "QCCAESCryptor.h"
#import "QCCAESPadCryptor.h"
#import "QCCAESPadBigCryptor.h"
 
#import "ToolCommon.h"
 
#import "QHex.h"
 
NS_ASSUME_NONNULL_BEGIN
 
@interface AESCryptorCommand ()
 
@property (nonatomic, copy,   readwrite, nullable) NSData * keyData;
@property (nonatomic, copy,   readwrite, nullable) NSData * ivData;
@property (nonatomic, assign, readwrite) BOOL               ecbMode;
 
// for subclasses to implement
 
+ (Class)cryptorClass;
+ (BOOL)encrypt;
- (BOOL)validateArguments;
 
@end
 
NS_ASSUME_NONNULL_END
 
@implementation AESCryptorCommand
 
+ (Class)cryptorClass {
    NSAssert(NO, @"implementation required");
    return nil;
}
 
+ (BOOL)encrypt {
    NSAssert(NO, @"implementation required");
    return YES;
}
 
- (BOOL)validateArguments {
    return (self.arguments.count == 1);
}
 
+ (NSString *)commandUsage {
    return [NSString stringWithFormat:@"%@ -k keyHexStr (-e | [-i ivHexStr]) file", [self commandName]];
}
 
- (NSString *)commandOptions {
    return @"k:i:e";
}
 
- (BOOL)setOption_k_argument:(NSString *)argument {
    self.keyData = [QHex optionalDataWithHexString:argument];
    return (self.keyData != nil);
}
 
- (BOOL)setOption_i_argument:(NSString *)argument {
    self.ivData = [QHex optionalDataWithHexString:argument];
    return (self.ivData != nil);
}
 
- (void)setOption_e {
    self.ecbMode = YES;
}
 
- (BOOL)validateOptionsAndArguments:(NSArray *)optionsAndArguments {
    BOOL    success;
    
    success = [super validateOptionsAndArguments:optionsAndArguments];
    if (success) {
        if ( ! [self validateArguments] ) {
            success = NO;
        } else if (self.keyData == nil) {
            success = NO;
        } else if (self.ecbMode && (self.ivData != nil)) {
            success = NO;           // IV is incompatible with ECB
        }
    }
    return success;
}
 
- (BOOL)runError:(NSError **)errorPtr {
    BOOL                success;
    NSData *            fileData;
    QCCAESCryptor *     op;
 
    fileData = [NSData dataWithContentsOfURL:[NSURL fileURLWithPath:self.arguments[0]] options:(NSDataReadingOptions) 0 error:errorPtr];
    success = (fileData != nil);
    
    if (success) {
        // We're playing fast'n'loose with types here.  The various cryptor operations 
        // don't share a command base class (becasue I don't want to have them coupled together) 
        // so we don't have a class we can use for "op".  Rather than write lots of pointless 
        // code just to keep the compiler happy, I tell the compile that "op" is of type 
        // QCCAESCryptor.  In reality it could be any of the other cryptor classes.
 
        if ([[self class] encrypt]) {
            op = [[[[self class] cryptorClass] alloc] initToEncryptInputData:fileData keyData:self.keyData];
        } else {
            op = [[[[self class] cryptorClass] alloc] initToDecryptInputData:fileData keyData:self.keyData];
        }
        if (self.ecbMode) {
            op.ivData = nil;
        } else if (self.ivData != nil) {
            op.ivData = self.ivData;
        }
        [[ToolCommon sharedInstance] synchronouslyRunOperation:op];
        if (op.error == nil) {
            (void) fwrite(op.outputData.bytes, op.outputData.length, 1, stdout);
        } else {
            if (errorPtr != NULL) {
                *errorPtr = op.error;
            }
            success = NO;
        }
    }
    
    return success;
}
 
@end
 
@implementation AESEncryptCommand
 
+ (NSString *)commandName {
    return @"aes-encrypt";
}
 
+ (Class)cryptorClass {
    return [QCCAESCryptor class];
}
 
+ (BOOL)encrypt {
    return YES;
}
 
@end
 
@implementation AESDecryptCommand
 
+ (NSString *)commandName {
    return @"aes-decrypt";
}
 
+ (Class)cryptorClass {
    return [QCCAESCryptor class];
}
 
+ (BOOL)encrypt {
    return NO;
}
 
@end
 
@implementation AESPadEncryptCommand
 
+ (NSString *)commandName {
    return @"aes-pad-encrypt";
}
 
+ (Class)cryptorClass {
    return [QCCAESPadCryptor class];
}
 
+ (BOOL)encrypt {
    return YES;
}
 
@end
 
@implementation AESPadDecryptCommand
 
+ (NSString *)commandName {
    return @"aes-pad-decrypt";
}
 
+ (Class)cryptorClass {
    return [QCCAESPadCryptor class];
}
 
+ (BOOL)encrypt {
    return NO;
}
 
@end
 
@implementation AESBigCryptorCommand
 
- (BOOL)validateArguments {
    return (self.arguments.count == 2);
}
 
+ (NSString *)commandUsage {
    return [NSString stringWithFormat:@"%@ -k keyHexStr (-e | [-i ivHexStr]) inputFile outputFile", [self commandName]];
}
 
- (BOOL)runError:(NSError **)errorPtr {
    BOOL                    success;
    NSInputStream *         inputStream;
    NSOutputStream *        outputStream;
    QCCAESPadBigCryptor *   op;
 
    inputStream = [NSInputStream inputStreamWithFileAtPath:self.arguments[0]];
    success = (inputStream != nil);
 
    if (success) {
        outputStream = [NSOutputStream outputStreamToFileAtPath:self.arguments[1] append:NO];
        success = (outputStream != nil);
    }
    
    if (success) {
        // We're playing fast'n'loose with types here.  The various cryptor operations 
        // don't share a command base class (becasue I don't want to have them coupled together) 
        // so we don't have a class we can use for "op".  Rather than write lots of pointless 
        // code just to keep the compiler happy, I tell the compile that "op" is of type 
        // QCCAESPadBigCryptor.  In reality it could be any of the other cryptor classes.
 
        if ([[self class] encrypt]) {
            op = [[[[self class] cryptorClass] alloc] initToEncryptInputStream:inputStream toOutputStream:outputStream keyData:self.keyData];
        } else {
            op = [[[[self class] cryptorClass] alloc] initToDecryptInputStream:inputStream toOutputStream:outputStream keyData:self.keyData];
        }
        if (self.ecbMode) {
            op.ivData = nil;
        } else if (self.ivData != nil) {
            op.ivData = self.ivData;
        }
        [[ToolCommon sharedInstance] synchronouslyRunOperation:op];
        if (op.error != nil) {
            if (errorPtr != NULL) {
                *errorPtr = op.error;
            }
            success = NO;
        }
    }
    
    return success;
}
 
@end
 
@implementation AESPadBigEncryptCommand
 
+ (NSString *)commandName {
    return @"aes-pad-big-encrypt";
}
 
+ (Class)cryptorClass {
    return [QCCAESPadBigCryptor class];
}
 
+ (BOOL)encrypt {
    return YES;
}
 
@end
 
@implementation AESPadBigDecryptCommand
 
+ (NSString *)commandName {
    return @"aes-pad-big-decrypt";
}
 
+ (Class)cryptorClass {
    return [QCCAESPadBigCryptor class];
}
 
+ (BOOL)encrypt {
    return NO;
}
 
@end


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