keychain/ot/OctagonControlServer.m

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #import <Foundation/Foundation.h>
  25 #import <objc/runtime.h>
  26 #import <Foundation/NSXPCConnection_Private.h>
  27
  28 #import <utilities/debugging.h>
  29 #import <Security/SecEntitlements.h>
  30 #import "keychain/ot/OctagonControlServer.h"
  31 #import "keychain/ot/OTManager.h"
  32 #import "keychain/ot/OT.h"
  33 #import "keychain/ot/OTConstants.h"
  34 #import "keychain/categories/NSError+UsefulConstructors.h"
  35
  36 #if OCTAGON
  37 @interface OctagonXPCEntitlementChecker ()
  38 @property OTManager* manager;
  39 @property id<OctagonEntitlementBearerProtocol> entitlementBearer;
  40 - (instancetype)initWithManager:(OTManager*)manager
  41               entitlementBearer:(id<OctagonEntitlementBearerProtocol>)bearer;
  42 @end
  43
  44 @implementation OctagonXPCEntitlementChecker
  45
  46 - (instancetype)initWithManager:(OTManager*)manager entitlementBearer:(id<OctagonEntitlementBearerProtocol>)bearer
  47 {
  48     // NSProxy does not implement init, so don't call super init
  49     _manager = manager;
  50     _entitlementBearer = bearer;
  51     return self;
  52 }
  53
  54 - (NSMethodSignature *)methodSignatureForSelector:(SEL)selector
  55 {
  56     return [self.manager methodSignatureForSelector:selector];
  57 }
  58
  59 - (void)forwardInvocation:(NSInvocation *)invocation
  60 {
  61     if(sel_isEqual(invocation.selector, @selector(fetchEscrowContents:contextID:reply:))) {
  62         if(![self.entitlementBearer valueForEntitlement:kSecEntitlementPrivateOctagonEscrow]) {
  63             secerror("Client %@ does not have entitlement %@, rejecting rpc", self.entitlementBearer, kSecEntitlementPrivateOctagonEscrow);
  64             [invocation setSelector:@selector(failFetchEscrowContents:contextID:reply:)];
  65             [invocation invokeWithTarget:self];
  66             return;
  67         }
  68     }
  69     [invocation invokeWithTarget:self.manager];
  70 }
  71
  72 - (void)failFetchEscrowContents:(NSString*)containerName
  73                       contextID:(NSString *)contextID
  74                           reply:(void (^)(NSData* _Nullable entropy,
  75                                           NSString* _Nullable bottleID,
  76                                           NSData* _Nullable signingPublicKey,
  77                                           NSError* _Nullable error))reply
  78 {
  79     reply(nil, nil, nil, [NSError errorWithDomain:NSOSStatusErrorDomain
  80                                              code:errSecMissingEntitlement
  81                                       description:[NSString stringWithFormat: @"Missing entitlement '%@'", kSecEntitlementPrivateOctagonEscrow]]);
  82 }
  83
  84 + (BOOL)conformsToProtocol:(Protocol *)protocol {
  85     return [[OTManager class] conformsToProtocol:protocol];
  86 }
  87
  88 // Launder a OctagonXPCEntitlementChecker into something that type-safely implements the protocol we're interested in
  89 + (id<OTControlProtocol>)createWithManager:(OTManager*)manager
  90                          entitlementBearer:(id<OctagonEntitlementBearerProtocol>)bearer
  91 {
  92     return (id<OTControlProtocol>) [[OctagonXPCEntitlementChecker alloc] initWithManager:manager entitlementBearer:bearer];
  93 }
  94 @end
  95 #endif // OCTAGON
  96
  97 @interface OctagonControlServer : NSObject <NSXPCListenerDelegate>
  98 @end
  99
 100 @implementation OctagonControlServer
 101
 102 - (BOOL)listener:(__unused NSXPCListener *)listener shouldAcceptNewConnection:(NSXPCConnection *)newConnection
 103 {
 104 #if OCTAGON
 105     NSNumber *num = [newConnection valueForEntitlement:kSecEntitlementPrivateOctagon];
 106     if (![num isKindOfClass:[NSNumber class]] || ![num boolValue]) {
 107         secerror("octagon: Client pid: %d doesn't have entitlement: %@",
 108                  [newConnection processIdentifier], kSecEntitlementPrivateOctagon);
 109         return NO;
 110     }
 111     // In the future, we should consider vending a proxy object that can return a nicer error.
 112     if (!OctagonIsEnabled()) {
 113         secerror("Octagon: Client pid: %d attempted to use Octagon, but Octagon is not enabled.",
 114                  newConnection.processIdentifier);
 115         return NO;
 116     }
 117
 118     secinfo("octagon", "received connection from client pid %d", [newConnection processIdentifier]);
 119     newConnection.exportedInterface = OTSetupControlProtocol([NSXPCInterface interfaceWithProtocol:@protocol(OTControlProtocol)]);
 120     newConnection.exportedObject = [OctagonXPCEntitlementChecker createWithManager:[OTManager manager] entitlementBearer:newConnection];
 121
 122     [newConnection resume];
 123
 124     return YES;
 125 #else // OCTAGON
 126     secerror("octagon does not exist on this platform");
 127     return NO;
 128 #endif // OCTAGON
 129 }
 130 @end
 131
 132 void
 133 OctagonControlServerInitialize(void)
 134 {
 135     static dispatch_once_t once;
 136     static OctagonControlServer *server;
 137     static NSXPCListener *listener;
 138
 139     dispatch_once(&once, ^{
 140         @autoreleasepool {
 141             server = [OctagonControlServer new];
 142
 143             listener = [[NSXPCListener alloc] initWithMachServiceName:@(kSecuritydOctagonServiceName)];
 144             listener.delegate = server;
 145             [listener resume];
 146         }
 147     });
 148 }