1 /*
2 * Copyright (c) 2010 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 #include <TargetConditionals.h>
30 #include <stdbool.h>
31 #include <strings.h>
32 #include <unistd.h>
33 #include <mach/vm_page_size.h>
34 #include <spawn_filtering_private.h>
35 #include "_libkernel_init.h"
36 #include "system-version-compat-support.h"
37
38 extern int mach_init(void);
39
40 #if SYSTEM_VERSION_COMPAT_ENABLED
41
42 #include <sys/sysctl.h>
43
44 extern bool _system_version_compat_check_path_suffix(const char *orig_path);
45 extern int _system_version_compat_open_shim(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
46 int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
47 int (*openat_syscall)(int, const char *, int, mode_t),
48 int (*fcntl_syscall)(int, int, long));
49
50 extern bool (*system_version_compat_check_path_suffix)(const char *orig_path);
51 extern int (*system_version_compat_open_shim)(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
52 int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
53 int (*openat_syscall)(int, const char *, int, mode_t),
54 int (*fcntl_syscall)(int, int, long));
55
56 extern system_version_compat_mode_t system_version_compat_mode;
57
58 int __sysctlbyname(const char *name, size_t namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen);
59 #endif /* SYSTEM_VERSION_COMPAT_ENABLED */
60
61 #if POSIX_SPAWN_FILTERING_ENABLED
62 struct _posix_spawn_args_desc;
63 extern bool (*posix_spawn_with_filter)(pid_t *pid, const char *fname, char * const *argp,
64 char * const *envp, struct _posix_spawn_args_desc *adp, int *ret);
65 extern bool _posix_spawn_with_filter(pid_t *pid, const char *fname, char * const *argp,
66 char * const *envp, struct _posix_spawn_args_desc *adp, int *ret);
67 extern int (*execve_with_filter)(char *fname, char **argp, char **envp);
68 extern int _execve_with_filter(char *fname, char **argp, char **envp);
69 #endif /* POSIX_SPAWN_FILTERING_ENABLED */
70
71 #if TARGET_OS_OSX
72 __attribute__((visibility("default")))
73 extern bool _os_xbs_chrooted;
74 bool _os_xbs_chrooted;
75 #endif /* TARGET_OS_OSX */
76
77 /* dlsym() funcptr is for legacy support in exc_catcher */
78 void* (*LIBKERNEL_FUNCTION_PTRAUTH(_dlsym))(void*, const char*) __attribute__((visibility("hidden")));
79
80 __attribute__((visibility("hidden")))
81 _libkernel_functions_t _libkernel_functions;
82
83
84 void
__libkernel_init(_libkernel_functions_t fns,const char * envp[],const char * apple[],const struct ProgramVars * vars)85 __libkernel_init(_libkernel_functions_t fns,
86 const char *envp[] __attribute__((unused)),
87 const char *apple[] __attribute__((unused)),
88 const struct ProgramVars *vars __attribute__((unused)))
89 {
90 _libkernel_functions = fns;
91 if (fns->dlsym) {
92 _dlsym = fns->dlsym;
93 }
94 mach_init();
95 #if TARGET_OS_OSX
96 for (size_t i = 0; envp[i]; i++) {
97
98 #if defined(__i386__) || defined(__x86_64__)
99 const char *VM_KERNEL_PAGE_SHIFT_ENV = "VM_KERNEL_PAGE_SIZE_4K=1";
100 if (vm_kernel_page_shift != 12 && strcmp(VM_KERNEL_PAGE_SHIFT_ENV, envp[i]) == 0) {
101 vm_kernel_page_shift = 12;
102 vm_kernel_page_size = 1 << vm_kernel_page_shift;
103 vm_kernel_page_mask = vm_kernel_page_size - 1;
104 }
105 #endif /* defined(__i386__) || defined(__x86_64__) */
106 }
107 #endif /* TARGET_OS_OSX */
108 }
109
110 void
__libkernel_init_late(_libkernel_late_init_config_t config)111 __libkernel_init_late(_libkernel_late_init_config_t config)
112 {
113 if (config->version >= 1) {
114 #if SYSTEM_VERSION_COMPAT_ENABLED
115 #if TARGET_OS_OSX && !defined(__i386__)
116 if (config->enable_system_version_compat) {
117 /* enable the version compatibility shim for this process (macOS only) */
118
119 /* first hook up the shims we reference from open{at}() */
120 system_version_compat_check_path_suffix = _system_version_compat_check_path_suffix;
121 system_version_compat_open_shim = _system_version_compat_open_shim;
122
123 system_version_compat_mode = SYSTEM_VERSION_COMPAT_MODE_MACOSX;
124
125 /*
126 * tell the kernel the shim is enabled for this process so it can shim any
127 * necessary sysctls
128 */
129 int enable = 1;
130 __sysctlbyname("kern.system_version_compat", strlen("kern.system_version_compat"),
131 NULL, NULL, &enable, sizeof(enable));
132 } else if ((config->version >= 2) && config->enable_ios_version_compat) {
133 /* enable the iOS ProductVersion compatibility shim for this process */
134
135 /* first hook up the shims we reference from open{at}() */
136 system_version_compat_check_path_suffix = _system_version_compat_check_path_suffix;
137 system_version_compat_open_shim = _system_version_compat_open_shim;
138
139 system_version_compat_mode = SYSTEM_VERSION_COMPAT_MODE_IOS;
140
141 /*
142 * We don't currently shim any sysctls for iOS apps running on macOS so we
143 * don't need to inform the kernel that this app has the SystemVersion shim enabled.
144 */
145 }
146 #endif /* TARGET_OS_OSX && !defined(__i386__) */
147
148 #endif /* SYSTEM_VERSION_COMPAT_ENABLED */
149
150 #if POSIX_SPAWN_FILTERING_ENABLED
151 if ((config->version >= 3) && config->enable_posix_spawn_filtering) {
152 posix_spawn_with_filter = _posix_spawn_with_filter;
153 execve_with_filter = _execve_with_filter;
154 }
155 #endif /* POSIX_SPAWN_FILTERING_ENABLED */
156 }
157 }
158
159 void
__libkernel_init_after_boot_tasks(_libkernel_init_after_boot_tasks_config_t config)160 __libkernel_init_after_boot_tasks(
161 _libkernel_init_after_boot_tasks_config_t config)
162 {
163 if (config->version >= 1) {
164 #if POSIX_SPAWN_FILTERING_ENABLED
165 if (config->enable_posix_spawn_filtering) {
166 posix_spawn_with_filter = _posix_spawn_with_filter;
167 execve_with_filter = _execve_with_filter;
168 }
169 #endif /* POSIX_SPAWN_FILTERING_ENABLED */
170 }
171 }
172