dyld3/PointerAuth.h

   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
  25
  26 #ifndef __DYLD_POINTER_AUTH_H__
  27 #define __DYLD_POINTER_AUTH_H__
  28
  29 #include <ptrauth.h>
  30
  31 #if __has_feature(ptrauth_calls)
  32 #define __ptrauth_dyld_address_auth __ptrauth(ptrauth_key_process_dependent_data, 1, 0)
  33 #define __ptrauth_dyld_function_ptr __ptrauth(ptrauth_key_process_dependent_code, 1, 0)
  34 #else
  35 #define __ptrauth_dyld_address_auth
  36 #define __ptrauth_dyld_function_ptr
  37 #endif
  38
  39 namespace dyld3 {
  40
  41 // On arm64e, signs the given pointer with the address of where it is stored.
  42 // Other archs just have a regular pointer
  43 #pragma clang diagnostic push
  44 #pragma clang diagnostic ignored "-Wptrauth-null-pointers"
  45 template<typename T>
  46 struct AuthenticatedValue {
  47     static_assert(sizeof(T) <= sizeof(uintptr_t));
  48
  49     AuthenticatedValue() {
  50         this->value = ptrauth_sign_unauthenticated(nullptr, ptrauth_key_process_dependent_data, this);
  51     }
  52     ~AuthenticatedValue() = default;
  53     AuthenticatedValue(const AuthenticatedValue& other) {
  54         this->value = ptrauth_auth_and_resign(other.value,
  55                                               ptrauth_key_process_dependent_data, &other,
  56                                               ptrauth_key_process_dependent_data, this);
  57     }
  58     AuthenticatedValue(AuthenticatedValue&& other) {
  59         this->value = ptrauth_auth_and_resign(other.value,
  60                                               ptrauth_key_process_dependent_data, &other,
  61                                               ptrauth_key_process_dependent_data, this);
  62         other.value = ptrauth_sign_unauthenticated(nullptr, ptrauth_key_process_dependent_data, &other);
  63     }
  64
  65     AuthenticatedValue& operator=(const AuthenticatedValue&) = delete;
  66     AuthenticatedValue& operator=(AuthenticatedValue&&) = delete;
  67
  68     // Add a few convenience methods for interoperating with values of the given type
  69     AuthenticatedValue& operator=(const T& other) {
  70         this->value = ptrauth_sign_unauthenticated(other, ptrauth_key_process_dependent_data, this);
  71         return *this;
  72     }
  73     bool operator==(const T& other) const {
  74         return ptrauth_auth_data(this->value, ptrauth_key_process_dependent_data, this) == other;
  75     }
  76     bool operator!=(const T& other) const {
  77         return ptrauth_auth_data(this->value, ptrauth_key_process_dependent_data, this) != other;
  78     }
  79
  80 private:
  81     const void* value;
  82 };
  83
  84
  85 #pragma clang diagnostic pop
  86
  87 } // namespace dyld3
  88
  89 #endif // __DYLD_POINTER_AUTH_H__
  90