bsd/tests/ptrauth_data_tests_sysctl.c

   1 /*
   2  * Copyright (c) 2020 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
  29 #if DEVELOPMENT || DEBUG
  30 #if __has_feature(ptrauth_calls)
  31
  32 #include <sys/errno.h>
  33 #include <sys/sysctl.h>
  34 #include <sys/ubc.h>
  35 #include <kern/kalloc.h>
  36 #include <libkern/libkern.h>
  37 #include <pexpert/pexpert.h>
  38
  39
  40 #include <mach/task.h>
  41 #include <kern/task.h>
  42 #include <sys/ubc_internal.h>
  43
  44 extern kern_return_t ptrauth_data_tests(void);
  45
  46 /*
  47  * Given an existing PAC pointer (ptr), its declaration type (decl), the (key)
  48  * used to sign it and the string discriminator (discr), extract the raw pointer
  49  * along with the signature and compare it with one computed on the fly
  50  * via ptrauth_sign_unauthenticated().
  51  *
  52  * If the two mismatch, return an error and fail the test.
  53  */
  54 #define VALIDATE_PTR(decl, ptr, key, discr) { \
  55         decl raw = *(decl *)&(ptr);      \
  56         decl cmp = ptrauth_sign_unauthenticated(ptr, key, \
  57                 ptrauth_blend_discriminator(&ptr, ptrauth_string_discriminator(discr))); \
  58         if (cmp != raw) { \
  59                 printf("kern.run_pac_test: %s (%s) (discr=%s) is not signed as expected (%p vs %p)\n", #decl, #ptr, #discr, raw, cmp); \
  60                 kr = EINVAL; \
  61         } \
  62 }
  63
  64 /*
  65  * Allocate the containing structure, and store a pointer to the desired member,
  66  * which should be subject to pointer signing.
  67  */
  68 #define ALLOC_VALIDATE_DATA_PTR(structure, decl, member, discr) { \
  69         structure *tmp =  kheap_alloc(KHEAP_TEMP, sizeof(structure), Z_WAITOK | Z_ZERO); \
  70         if (!tmp) return ENOMEM; \
  71         tmp->member = (void*)0xffffffff41414141; \
  72         VALIDATE_DATA_PTR(decl, tmp->member, discr) \
  73         kheap_free(KHEAP_TEMP, tmp, sizeof(structure)); \
  74 }
  75
  76 #define VALIDATE_DATA_PTR(decl, ptr, discr) VALIDATE_PTR(decl, ptr, ptrauth_key_process_independent_data, discr)
  77
  78 /*
  79  * Validate that a pointer that is supposed to be signed, is, and that the signature
  80  * matches based on signing key, location and discriminator
  81  */
  82 static int
  83 sysctl_run_ptrauth_data_tests SYSCTL_HANDLER_ARGS
  84 {
  85         #pragma unused(arg1, arg2, oidp)
  86
  87         unsigned int dummy;
  88         int error, changed, kr;
  89         error = sysctl_io_number(req, 0, sizeof(dummy), &dummy, &changed);
  90         if (error || !changed) {
  91                 return error;
  92         }
  93
  94         /* proc_t */
  95         ALLOC_VALIDATE_DATA_PTR(struct proc, void *, task, "proc.task");
  96         ALLOC_VALIDATE_DATA_PTR(struct proc, struct proc *, p_pptr, "proc.p_pptr");
  97         ALLOC_VALIDATE_DATA_PTR(struct proc, struct vnode *, p_textvp, "proc.p_textvp");
  98         ALLOC_VALIDATE_DATA_PTR(struct proc, struct pgrp *, p_pgrp, "proc.p_pgrp");
  99
 100         /* cs_blob */
 101         ALLOC_VALIDATE_DATA_PTR(struct cs_blob, struct cs_blob *, csb_next, "cs_blob.csb_next");
 102         ALLOC_VALIDATE_DATA_PTR(struct cs_blob, const CS_CodeDirectory *, csb_cd, "cs_blob.csb_cd");
 103         ALLOC_VALIDATE_DATA_PTR(struct cs_blob, const char *, csb_teamid, "cs_blob.csb_teamid");
 104         ALLOC_VALIDATE_DATA_PTR(struct cs_blob, const CS_GenericBlob *, csb_entitlements_blob, "cs_blob.csb_entitlements_blob");
 105         ALLOC_VALIDATE_DATA_PTR(struct cs_blob, void *, csb_entitlements, "cs_blob.csb_entitlements");
 106
 107         /* The rest of the tests live in osfmk/ */
 108         kr = ptrauth_data_tests();
 109
 110         if (error == 0) {
 111                 error = mach_to_bsd_errno(kr);
 112         }
 113
 114         return kr;
 115 }
 116
 117 SYSCTL_PROC(_kern, OID_AUTO, run_ptrauth_data_tests,
 118     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_MASKED,
 119     0, 0, sysctl_run_ptrauth_data_tests, "I", "");
 120
 121 #endif /*  __has_feature(ptrauth_calls) */
 122 #endif /* DEVELOPMENT || DEBUG */