osfmk/kern/copyout_shim.c

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <mach/mach_types.h>
  29 #include <mach/vm_param.h>
  30 #include <string.h>
  31 #include <pexpert/pexpert.h>
  32 #include <kern/copyout_shim.h>
  33
  34 #if (DEVELOPMENT || DEBUG)
  35 #define UNUSED_IN_RELEASE(x)
  36 #else
  37 //supress compiler warnings about unused variables
  38 #define UNUSED_IN_RELEASE(x) (void)(x)
  39 #endif /* (DEVELOPMENT || DEBUG) */
  40
  41
  42 #if (DEVELOPMENT || DEBUG)
  43 copyout_shim_fn_t copyout_shim_fn=NULL;
  44 unsigned co_src_flags=0;
  45 #endif
  46
  47 kern_return_t register_copyout_shim(void (*fn)(const void *,user_addr_t,vm_size_t,unsigned co_src),unsigned types)
  48 {
  49 #if (DEVELOPMENT || DEBUG)
  50     int copyout_shim_enabled=0;
  51
  52     if(!fn)
  53     {
  54         /* unregistration is always allowed */
  55         copyout_shim_fn=NULL;
  56         return KERN_SUCCESS;
  57     }
  58
  59     if(copyout_shim_fn)
  60     {
  61         //need to unregister first before registering a new one.
  62         return KERN_FAILURE;
  63     }
  64
  65     if(!PE_parse_boot_argn("enable_copyout_shim",&copyout_shim_enabled,sizeof(copyout_shim_enabled)) || !copyout_shim_enabled)
  66     {
  67         return KERN_FAILURE;
  68     }
  69
  70
  71     co_src_flags=types;
  72     copyout_shim_fn=fn;
  73     return KERN_SUCCESS;
  74 #else
  75     UNUSED_IN_RELEASE(fn);
  76     UNUSED_IN_RELEASE(types);
  77     return KERN_FAILURE;
  78 #endif
  79 }
  80
  81 void *cos_kernel_unslide(const void *ptr)
  82 {
  83 #if (DEVELOPMENT || DEBUG)
  84     return (void *)(VM_KERNEL_UNSLIDE(ptr));
  85 #else
  86     UNUSED_IN_RELEASE(ptr);
  87     return NULL;
  88 #endif
  89 }
  90
  91 void *cos_kernel_reslide(const void *ptr)
  92 {
  93 #if (DEVELOPMENT || DEBUG)
  94     return (void *)(VM_KERNEL_SLIDE(ptr));
  95 #else
  96     UNUSED_IN_RELEASE(ptr);
  97     return NULL;
  98 #endif
  99 }