xref: /xnu-11215/libkern/OSKextLib.cpp (revision bb611c8f)
1 /*
2  * Copyright (c) 2008-2016 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,
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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 extern "C" {
30 #include <libkern/OSKextLibPrivate.h>
31 #include <libkern/mkext.h>
32 };
33 
34 #include <libkern/c++/OSContainers.h>
35 #include <libkern/c++/OSKext.h>
36 #include <libkern/OSKextLib.h>
37 #include <libkern/OSKextLibPrivate.h>
38 
39 extern "C" {
40 #if PRAGMA_MARK
41 #pragma mark C-based kext interface (loading/loaded kexts only)
42 #endif
43 /*********************************************************************
44 *********************************************************************/
45 kern_return_t
46 OSKextLoadKextWithIdentifier(const char * bundle_id)
47 {
48 	return OSKext::loadKextWithIdentifier(bundle_id);
49 }
50 
51 uint32_t OSKextGetLoadTagForIdentifier(const char * kextIdentifier);
52 /*********************************************************************
53 *********************************************************************/
54 uint32_t
55 OSKextGetLoadTagForIdentifier(const char * kextIdentifier)
56 {
57 	uint32_t result  = kOSKextInvalidLoadTag;
58 	OSKext * theKext = NULL; // must release
59 
60 	if (!kextIdentifier) {
61 		goto finish;
62 	}
63 
64 	theKext = OSKext::lookupKextWithIdentifier(kextIdentifier);
65 	if (theKext && theKext->isLoaded()) {
66 		result = theKext->getLoadTag();
67 	}
68 finish:
69 	if (theKext) {
70 		theKext->release();
71 	}
72 	return result;
73 }
74 
75 /*********************************************************************
76 *********************************************************************/
77 
78 // FIXME: Implementation of this function is hidden from the static analyzer.
79 // The analyzer is worried about the lack of release and suggests
80 // refactoring the code into the typical non-owning container pattern.
81 // Feel free to remove the #ifndef and address the warning!
82 #ifndef __clang_analyzer__
83 OSReturn
84 OSKextRetainKextWithLoadTag(uint32_t loadTag)
85 {
86 	OSReturn   result = kOSKextReturnNotFound;
87 	OSKext   * theKext = NULL;// do not release; as this function is a retain
88 
89 	if (loadTag == kOSKextInvalidLoadTag) {
90 		result = kOSKextReturnInvalidArgument;
91 		goto finish;
92 	}
93 	theKext = OSKext::lookupKextWithLoadTag(loadTag);
94 	if (theKext) {
95 		result = kOSReturnSuccess;
96 
97 		OSKextLog(theKext,
98 		    kOSKextLogDebugLevel |
99 		    kOSKextLogKextBookkeepingFlag,
100 		    "Kext %s (load tag %d) has been retained.",
101 		    theKext->getIdentifierCString(),
102 		    loadTag);
103 
104 		/* Call this after so a log message about autounload comes second.
105 		 */
106 		theKext->setAutounloadEnabled(true);
107 	} else {
108 		OSKextLog(theKext,
109 		    kOSKextLogErrorLevel |
110 		    kOSKextLogKextBookkeepingFlag,
111 		    "Can't retain kext with load tag %d - no such kext is loaded.",
112 		    loadTag);
113 	}
114 finish:
115 	return result;
116 }
117 #endif // __clang_analyzer__
118 
119 /*********************************************************************
120 *********************************************************************/
121 
122 // FIXME: Implementation of this function is hidden from the static analyzer.
123 // The analyzer is worried about the double release and suggests
124 // refactoring the code into the typical non-owning container pattern.
125 // Feel free to remove the #ifndef and address the warning!
126 #ifndef __clang_analyzer__
127 OSReturn
128 OSKextReleaseKextWithLoadTag(uint32_t loadTag)
129 {
130 	OSReturn result  = kOSKextReturnNotFound;
131 	OSKext * theKext = NULL; // must release twice!
132 
133 	if (loadTag == kOSKextInvalidLoadTag) {
134 		result = kOSKextReturnInvalidArgument;
135 		goto finish;
136 	}
137 	theKext = OSKext::lookupKextWithLoadTag(loadTag);
138 	if (theKext) {
139 		result = kOSReturnSuccess;
140 		OSKext::considerUnloads(); // schedule autounload pass
141 		theKext->release(); // do the release the caller wants
142 		theKext->release(); // now do the release on the lookup
143 		OSKextLog(theKext,
144 		    kOSKextLogDebugLevel |
145 		    kOSKextLogKextBookkeepingFlag,
146 		    "Kext %s (load tag %d) has been released.",
147 		    theKext->getIdentifierCString(),
148 		    loadTag);
149 	} else {
150 		OSKextLog(theKext,
151 		    kOSKextLogErrorLevel |
152 		    kOSKextLogKextBookkeepingFlag,
153 		    "Can't release kext with load tag %d - no such kext is loaded.",
154 		    loadTag);
155 	}
156 
157 	// xxx - should I check that the refcount of the OSKext is above the lower bound?
158 	// xxx - do we want a OSKextGetRetainCountOfKextWithLoadTag()?
159 finish:
160 	return result;
161 }
162 #endif // __clang_analyzer__
163 
164 /*********************************************************************
165 * Not to be called by the kext being unloaded!
166 *********************************************************************/
167 OSReturn
168 OSKextUnloadKextWithLoadTag(uint32_t loadTag)
169 {
170 	return OSKext::removeKextWithLoadTag(loadTag,
171 	           /* terminateServicesAndRemovePersonalitiesFlag */ false);
172 }
173 
174 
175 #if PRAGMA_MARK
176 #pragma mark Kext Requests
177 #endif
178 /*********************************************************************
179 * Kext Requests
180 *********************************************************************/
181 OSReturn
182 OSKextRequestResource(
183 	const char                    * kextIdentifier,
184 	const char                    * resourceName,
185 	OSKextRequestResourceCallback   callback,
186 	void                          * context,
187 	OSKextRequestTag              * requestTagOut)
188 {
189 	return OSKext::requestResource(kextIdentifier, resourceName,
190 	           callback, context, requestTagOut);
191 }
192 
193 /*********************************************************************
194 *********************************************************************/
195 OSReturn
196 OSKextCancelRequest(
197 	OSKextRequestTag    requestTag,
198 	void             ** contextOut)
199 {
200 	return OSKext::cancelRequest(requestTag, contextOut);
201 }
202 
203 #if PRAGMA_MARK
204 #pragma mark MIG Functions & Wrappers
205 #endif
206 /*********************************************************************
207 * IMPORTANT: vm_map_copyout_size() consumes the requestIn copy
208 * object on success. Therefore once it has been invoked successfully,
209 * this routine *must* return KERN_SUCCESS, regardless of our actual
210 * result. Our contract with the caller is that requestIn must be
211 * caller-deallocated if we return an error. We use op_result to return
212 * the real result of our work.
213 *********************************************************************/
214 kern_return_t
215 kext_request(
216 	host_priv_t                             hostPriv,
217 	/* in only */ uint32_t                 clientLogSpec,
218 	/* in only */ vm_offset_t              requestIn,
219 	/* in only */ mach_msg_type_number_t   requestLengthIn,
220 	/* out only */ vm_offset_t            * responseOut,
221 	/* out only */ mach_msg_type_number_t * responseLengthOut,
222 	/* out only */ vm_offset_t            * logDataOut,
223 	/* out only */ mach_msg_type_number_t * logDataLengthOut,
224 	/* out only */ kern_return_t          * op_result)
225 {
226 	kern_return_t     result          = KERN_FAILURE;
227 	vm_map_address_t  map_addr        = 0; // do not free/deallocate
228 	char            * request         = NULL;// must vm_deallocate
229 
230 	mkext2_header   * mkextHeader     = NULL;// do not release
231 	bool              isMkext         = false;
232 
233 	char            * response        = NULL;// must kmem_free
234 	uint32_t          responseLength  = 0;
235 	char            * logData         = NULL;// must kmem_free
236 	uint32_t          logDataLength   = 0;
237 
238 	/* MIG doesn't pass "out" parameters as empty, so clear them immediately
239 	 * just in case, or MIG will try to copy out bogus data.
240 	 */
241 	*op_result = KERN_FAILURE;
242 	*responseOut = 0;
243 	*responseLengthOut = 0;
244 	*logDataOut = 0;
245 	*logDataLengthOut = 0;
246 
247 	/* Check for input. Don't discard what isn't there, though.
248 	 */
249 	if (!requestLengthIn || !requestIn) {
250 		OSKextLog(/* kext */ NULL,
251 		    kOSKextLogErrorLevel |
252 		    kOSKextLogIPCFlag,
253 		    "Invalid request from user space (no data).");
254 		*op_result = KERN_INVALID_ARGUMENT;
255 		goto finish;
256 	}
257 
258 	result = vm_map_copyout_size(kernel_map, &map_addr, (vm_map_copy_t)requestIn, requestLengthIn);
259 	if (result != KERN_SUCCESS) {
260 		OSKextLog(/* kext */ NULL,
261 		    kOSKextLogErrorLevel |
262 		    kOSKextLogIPCFlag,
263 		    "vm_map_copyout() failed for request from user space.");
264 		/*
265 		 * If we return an error it is our caller's responsibility to
266 		 * deallocate the requestIn copy object, so do not deallocate it
267 		 * here. See comment above.
268 		 */
269 		goto finish;
270 	}
271 	request = CAST_DOWN(char *, map_addr);
272 
273 	/* Check if request is an mkext; this is always a load request
274 	 * and requires root access. If it isn't an mkext, see if it's
275 	 * an XML request, and check the request to see if that requires
276 	 * root access.
277 	 */
278 	if (requestLengthIn > sizeof(mkext2_header)) {
279 		mkextHeader = (mkext2_header *)request;
280 		if (MKEXT_GET_MAGIC(mkextHeader) == MKEXT_MAGIC &&
281 		    MKEXT_GET_SIGNATURE(mkextHeader) == MKEXT_SIGN) {
282 			isMkext = true;
283 		}
284 	}
285 
286 	if (isMkext) {
287 #if defined(SECURE_KERNEL) || !CONFIG_KXLD
288 		// xxx - something tells me if we have a secure kernel we don't even
289 		// xxx - want to log a message here. :-)
290 		*op_result = KERN_NOT_SUPPORTED;
291 		goto finish;
292 #else
293 		// xxx - can we find out if calling task is kextd?
294 		// xxx - can we find the name of the calling task?
295 		if (hostPriv == HOST_PRIV_NULL) {
296 			OSKextLog(/* kext */ NULL,
297 			    kOSKextLogErrorLevel |
298 			    kOSKextLogLoadFlag | kOSKextLogIPCFlag,
299 			    "Attempt by non-root process to load a kext.");
300 			*op_result = kOSKextReturnNotPrivileged;
301 			goto finish;
302 		}
303 
304 		*op_result = OSKext::loadFromMkext((OSKextLogSpec)clientLogSpec,
305 		    request, requestLengthIn,
306 		    &logData, &logDataLength);
307 
308 #endif /* defined(SECURE_KERNEL) */
309 	} else {
310 		/* If the request isn't an mkext, then is should be XML. Parse it
311 		 * if possible and hand the request over to OSKext.
312 		 */
313 		*op_result = OSKext::handleRequest(hostPriv,
314 		    (OSKextLogSpec)clientLogSpec,
315 		    request, requestLengthIn,
316 		    &response, &responseLength,
317 		    &logData, &logDataLength);
318 	}
319 
320 	if (response && responseLength > 0) {
321 		kern_return_t copyin_result;
322 
323 		copyin_result = vm_map_copyin(kernel_map,
324 		    CAST_USER_ADDR_T(response), responseLength,
325 		    /* src_destroy */ false, (vm_map_copy_t *)responseOut);
326 		if (copyin_result == KERN_SUCCESS) {
327 			*responseLengthOut = responseLength;
328 		} else {
329 			OSKextLog(/* kext */ NULL,
330 			    kOSKextLogErrorLevel |
331 			    kOSKextLogIPCFlag,
332 			    "Failed to copy response to request from user space.");
333 			*op_result = copyin_result; // xxx - should we map to our own code?
334 			*responseOut = 0;
335 			*responseLengthOut = 0;
336 			goto finish;
337 		}
338 	}
339 
340 	if (logData && logDataLength > 0) {
341 		kern_return_t copyin_result;
342 
343 		copyin_result = vm_map_copyin(kernel_map,
344 		    CAST_USER_ADDR_T(logData), logDataLength,
345 		    /* src_destroy */ false, (vm_map_copy_t *)logDataOut);
346 		if (copyin_result == KERN_SUCCESS) {
347 			*logDataLengthOut = logDataLength;
348 		} else {
349 			OSKextLog(/* kext */ NULL,
350 			    kOSKextLogErrorLevel |
351 			    kOSKextLogIPCFlag,
352 			    "Failed to copy log data for request from user space.");
353 			*op_result = copyin_result; // xxx - should we map to our own code?
354 			*logDataOut = 0;
355 			*logDataLengthOut = 0;
356 			goto finish;
357 		}
358 	}
359 
360 finish:
361 	if (request) {
362 		(void)vm_deallocate(kernel_map, (vm_offset_t)request, requestLengthIn);
363 	}
364 	if (response) {
365 		/* 11981737 - clear uninitialized data in last page */
366 		kmem_free(kernel_map, (vm_offset_t)response, round_page(responseLength));
367 	}
368 	if (logData) {
369 		/* 11981737 - clear uninitialized data in last page */
370 		kmem_free(kernel_map, (vm_offset_t)logData, round_page(logDataLength));
371 	}
372 
373 	return result;
374 }
375 
376 /*********************************************************************
377 * Gets the vm_map for the current kext
378 *********************************************************************/
379 extern vm_offset_t segPRELINKTEXTB;
380 extern vm_offset_t segLINKB;
381 extern unsigned long segSizePRELINKTEXT;
382 extern vm_map_t g_kext_map;
383 
384 vm_map_t
385 kext_get_vm_map(kmod_info_t *info)
386 {
387 	vm_map_t kext_map = NULL;
388 	kc_format_t kcformat;
389 
390 	if (PE_get_primary_kc_format(&kcformat) && kcformat == KCFormatFileset) {
391 		/* Check if the kext is from the boot KC */
392 		assert(segLINKB >= (segPRELINKTEXTB + segSizePRELINKTEXT));
393 		if ((info->address >= segPRELINKTEXTB) &&
394 		    (info->address < segLINKB)) {
395 			kext_map = kernel_map;
396 		} else {
397 			kext_map = g_kext_map;
398 		}
399 	} else {
400 		if ((info->address >= segPRELINKTEXTB) &&
401 		    (info->address < (segPRELINKTEXTB + segSizePRELINKTEXT))) {
402 			kext_map = kernel_map;
403 		} else {
404 			kext_map = g_kext_map;
405 		}
406 	}
407 
408 	return kext_map;
409 }
410 
411 
412 #if PRAGMA_MARK
413 /********************************************************************/
414 #pragma mark Weak linking support
415 /********************************************************************/
416 #endif
417 void
418 kext_weak_symbol_referenced(void)
419 {
420 	panic("A kext referenced an unresolved weak symbol\n");
421 }
422 
423 const void * const gOSKextUnresolved = (const void *)&kext_weak_symbol_referenced;
424 
425 #if PRAGMA_MARK
426 #pragma mark Kernel-Internal C Functions
427 #endif
428 /*********************************************************************
429 * Called from startup.c.
430 *********************************************************************/
431 void
432 OSKextRemoveKextBootstrap(void)
433 {
434 	OSKext::removeKextBootstrap();
435 	return;
436 }
437 
438 #if CONFIG_DTRACE
439 /*********************************************************************
440 *********************************************************************/
441 void
442 OSKextRegisterKextsWithDTrace(void)
443 {
444 	OSKext::registerKextsWithDTrace();
445 	return;
446 }
447 #endif /* CONFIG_DTRACE */
448 
449 /*********************************************************************
450 *********************************************************************/
451 void
452 kext_dump_panic_lists(int (*printf_func)(const char * fmt, ...))
453 {
454 	OSKext::printKextPanicLists(printf_func);
455 	return;
456 }
457 
458 #if PRAGMA_MARK
459 #pragma mark Kmod Compatibility Functions
460 #endif
461 /*********************************************************************
462 **********************************************************************
463 *                    KMOD COMPATIBILITY FUNCTIONS                    *
464 *              (formerly in kmod.c, or C++ bridges from)             *
465 **********************************************************************
466 **********************************************************************
467 * These two functions are used in various places in the kernel, but
468 * are not exported. We might rename them at some point to start with
469 * kext_ or OSKext.
470 *
471 * kmod_panic_dump() must not be called outside of a panic context.
472 * kmod_dump_log() must not be called in a panic context.
473 *********************************************************************/
474 void
475 kmod_panic_dump(vm_offset_t * addr, unsigned int cnt)
476 {
477 	extern int paniclog_append_noflush(const char *format, ...) __printflike(1, 2);
478 
479 	OSKext::printKextsInBacktrace(addr, cnt, &paniclog_append_noflush, 0);
480 
481 	return;
482 }
483 
484 /********************************************************************/
485 void kmod_dump_log(vm_offset_t *addr, unsigned int cnt, boolean_t doUnslide);
486 
487 void
488 kmod_dump_log(
489 	vm_offset_t * addr,
490 	unsigned int cnt,
491 	boolean_t doUnslide)
492 {
493 	uint32_t flags = OSKext::kPrintKextsLock;
494 	if (doUnslide) {
495 		flags |= OSKext::kPrintKextsUnslide;
496 	}
497 	OSKext::printKextsInBacktrace(addr, cnt, &printf, flags);
498 }
499 
500 void *
501 OSKextKextForAddress(const void *addr)
502 {
503 	return OSKext::kextForAddress(addr);
504 }
505 
506 
507 /*********************************************************************
508 * Compatibility implementation for kmod_get_info() host_priv routine.
509 * Only supported on old 32-bit architectures.
510 *********************************************************************/
511 
512 #if PRAGMA_MARK
513 #pragma mark Loaded Kext Summary
514 #endif
515 
516 void
517 OSKextLoadedKextSummariesUpdated(void)
518 {
519 	// Do nothing.
520 }
521 };
522