xref: /xnu-11215/libkern/OSKextLib.cpp (revision 76e12aa3)
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,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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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 
41 #if PRAGMA_MARK
42 #pragma mark C-based kext interface (loading/loaded kexts only)
43 #endif
44 /*********************************************************************
45 *********************************************************************/
46 kern_return_t 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) theKext->release();
70     return result;
71 }
72 
73 /*********************************************************************
74 *********************************************************************/
75 OSReturn OSKextRetainKextWithLoadTag(uint32_t loadTag)
76 {
77     OSReturn   result = kOSKextReturnNotFound;
78     OSKext   * theKext = NULL;  // do not release; as this function is a retain
79 
80     if (loadTag == kOSKextInvalidLoadTag) {
81         result = kOSKextReturnInvalidArgument;
82         goto finish;
83     }
84     theKext = OSKext::lookupKextWithLoadTag(loadTag);
85     if (theKext) {
86         result = kOSReturnSuccess;
87 
88         OSKextLog(theKext,
89             kOSKextLogDebugLevel |
90             kOSKextLogKextBookkeepingFlag,
91             "Kext %s (load tag %d) has been retained.",
92             theKext->getIdentifierCString(),
93             loadTag);
94 
95        /* Call this after so a log message about autounload comes second.
96         */
97         theKext->setAutounloadEnabled(true);
98     } else {
99         OSKextLog(theKext,
100             kOSKextLogErrorLevel |
101             kOSKextLogKextBookkeepingFlag,
102             "Can't retain kext with load tag %d - no such kext is loaded.",
103            loadTag);
104     }
105 finish:
106     return result;
107 }
108 
109 /*********************************************************************
110 *********************************************************************/
111 OSReturn OSKextReleaseKextWithLoadTag(uint32_t loadTag)
112 {
113     OSReturn result  = kOSKextReturnNotFound;
114     OSKext * theKext = NULL;  // must release twice!
115 
116     if (loadTag == kOSKextInvalidLoadTag) {
117         result = kOSKextReturnInvalidArgument;
118         goto finish;
119     }
120     theKext = OSKext::lookupKextWithLoadTag(loadTag);
121     if (theKext) {
122         result = kOSReturnSuccess;
123         OSKext::considerUnloads();  // schedule autounload pass
124         theKext->release();  // do the release the caller wants
125         theKext->release();  // now do the release on the lookup
126         OSKextLog(theKext,
127             kOSKextLogDebugLevel |
128             kOSKextLogKextBookkeepingFlag,
129             "Kext %s (load tag %d) has been released.",
130             theKext->getIdentifierCString(),
131             loadTag);
132     } else {
133         OSKextLog(theKext,
134             kOSKextLogErrorLevel |
135             kOSKextLogKextBookkeepingFlag,
136             "Can't release kext with load tag %d - no such kext is loaded.",
137            loadTag);
138     }
139 
140     // xxx - should I check that the refcount of the OSKext is above the lower bound?
141     // xxx - do we want a OSKextGetRetainCountOfKextWithLoadTag()?
142 finish:
143     return result;
144 }
145 
146 /*********************************************************************
147 * Not to be called by the kext being unloaded!
148 *********************************************************************/
149 OSReturn OSKextUnloadKextWithLoadTag(uint32_t loadTag)
150 {
151     return OSKext::removeKextWithLoadTag(loadTag,
152         /* terminateServicesAndRemovePersonalitiesFlag */ false);
153 }
154 
155 
156 #if PRAGMA_MARK
157 #pragma mark Kext Requests
158 #endif
159 /*********************************************************************
160 * Kext Requests
161 *********************************************************************/
162 OSReturn OSKextRequestResource(
163     const char                    * kextIdentifier,
164     const char                    * resourceName,
165     OSKextRequestResourceCallback   callback,
166     void                          * context,
167     OSKextRequestTag              * requestTagOut)
168 {
169     return OSKext::requestResource(kextIdentifier, resourceName,
170         callback, context, requestTagOut);
171 }
172 
173 /*********************************************************************
174 *********************************************************************/
175 OSReturn OSKextCancelRequest(
176     OSKextRequestTag    requestTag,
177     void             ** contextOut)
178 {
179     return OSKext::cancelRequest(requestTag, contextOut);
180 }
181 
182 #if PRAGMA_MARK
183 #pragma mark MIG Functions & Wrappers
184 #endif
185 /*********************************************************************
186 * IMPORTANT: Once we have done the vm_map_copyout(), we *must* return
187 * KERN_SUCCESS or the kernel map gets messed up (reason as yet
188 * unknown). We use op_result to return the real result of our work.
189 *********************************************************************/
190 kern_return_t kext_request(
191     host_priv_t                             hostPriv,
192     /* in only */  uint32_t                 clientLogSpec,
193     /* in only */  vm_offset_t              requestIn,
194     /* in only */  mach_msg_type_number_t   requestLengthIn,
195     /* out only */ vm_offset_t            * responseOut,
196     /* out only */ mach_msg_type_number_t * responseLengthOut,
197     /* out only */ vm_offset_t            * logDataOut,
198     /* out only */ mach_msg_type_number_t * logDataLengthOut,
199     /* out only */ kern_return_t          * op_result)
200 {
201     kern_return_t     result          = KERN_FAILURE;
202     vm_map_address_t  map_addr        = 0;     // do not free/deallocate
203     char            * request         = NULL;  // must vm_deallocate
204 
205     mkext2_header   * mkextHeader     = NULL;  // do not release
206     bool              isMkext         = false;
207 
208     char            * response        = NULL;  // must kmem_free
209     uint32_t          responseLength  = 0;
210     char            * logData         = NULL;  // must kmem_free
211     uint32_t          logDataLength   = 0;
212 
213    /* MIG doesn't pass "out" parameters as empty, so clear them immediately
214     * just in case, or MIG will try to copy out bogus data.
215     */
216     *op_result = KERN_FAILURE;
217     *responseOut = NULL;
218     *responseLengthOut = 0;
219     *logDataOut = NULL;
220     *logDataLengthOut = 0;
221 
222    /* Check for input. Don't discard what isn't there, though.
223     */
224     if (!requestLengthIn || !requestIn) {
225 		OSKextLog(/* kext */ NULL,
226             kOSKextLogErrorLevel |
227             kOSKextLogIPCFlag,
228             "Invalid request from user space (no data).");
229         *op_result = KERN_INVALID_ARGUMENT;
230         goto finish;
231     }
232 
233    /* Once we have done the vm_map_copyout(), we *must* return KERN_SUCCESS
234     * or the kernel map gets messed up (reason as yet unknown). We will use
235     * op_result to return the real result of our work.
236     */
237     result = vm_map_copyout(kernel_map, &map_addr, (vm_map_copy_t)requestIn);
238     if (result != KERN_SUCCESS) {
239         OSKextLog(/* kext */ NULL,
240             kOSKextLogErrorLevel |
241             kOSKextLogIPCFlag,
242             "vm_map_copyout() failed for request from user space.");
243         vm_map_copy_discard((vm_map_copy_t)requestIn);
244         goto finish;
245     }
246     request = CAST_DOWN(char *, map_addr);
247 
248    /* Check if request is an mkext; this is always a load request
249     * and requires root access. If it isn't an mkext, see if it's
250     * an XML request, and check the request to see if that requires
251     * root access.
252     */
253     if (requestLengthIn > sizeof(mkext2_header)) {
254         mkextHeader = (mkext2_header *)request;
255         if (MKEXT_GET_MAGIC(mkextHeader) == MKEXT_MAGIC &&
256             MKEXT_GET_SIGNATURE(mkextHeader) == MKEXT_SIGN) {
257 
258             isMkext = true;
259         }
260     }
261 
262     if (isMkext) {
263 #ifdef SECURE_KERNEL
264         // xxx - something tells me if we have a secure kernel we don't even
265         // xxx - want to log a message here. :-)
266         *op_result = KERN_NOT_SUPPORTED;
267         goto finish;
268 #else
269         // xxx - can we find out if calling task is kextd?
270         // xxx - can we find the name of the calling task?
271         if (hostPriv == HOST_PRIV_NULL) {
272             OSKextLog(/* kext */ NULL,
273                 kOSKextLogErrorLevel |
274                 kOSKextLogLoadFlag | kOSKextLogIPCFlag,
275                 "Attempt by non-root process to load a kext.");
276             *op_result = kOSKextReturnNotPrivileged;
277             goto finish;
278         }
279 
280         *op_result = OSKext::loadFromMkext((OSKextLogSpec)clientLogSpec,
281             request, requestLengthIn,
282             &logData, &logDataLength);
283 
284 #endif /* defined(SECURE_KERNEL) */
285 
286     } else {
287 
288        /* If the request isn't an mkext, then is should be XML. Parse it
289         * if possible and hand the request over to OSKext.
290         */
291         *op_result = OSKext::handleRequest(hostPriv,
292             (OSKextLogSpec)clientLogSpec,
293             request, requestLengthIn,
294             &response, &responseLength,
295             &logData, &logDataLength);
296     }
297 
298     if (response && responseLength > 0) {
299         kern_return_t copyin_result;
300 
301         copyin_result = vm_map_copyin(kernel_map,
302             CAST_USER_ADDR_T(response), responseLength,
303             /* src_destroy */ false, (vm_map_copy_t *)responseOut);
304         if (copyin_result == KERN_SUCCESS) {
305             *responseLengthOut = responseLength;
306         } else {
307             OSKextLog(/* kext */ NULL,
308                 kOSKextLogErrorLevel |
309                 kOSKextLogIPCFlag,
310                 "Failed to copy response to request from user space.");
311             *op_result = copyin_result;  // xxx - should we map to our own code?
312             *responseOut = NULL;
313             *responseLengthOut = 0;
314             goto finish;
315         }
316     }
317 
318     if (logData && logDataLength > 0) {
319         kern_return_t copyin_result;
320 
321         copyin_result = vm_map_copyin(kernel_map,
322             CAST_USER_ADDR_T(logData), logDataLength,
323             /* src_destroy */ false, (vm_map_copy_t *)logDataOut);
324         if (copyin_result == KERN_SUCCESS) {
325             *logDataLengthOut = logDataLength;
326         } else {
327             OSKextLog(/* kext */ NULL,
328                 kOSKextLogErrorLevel |
329                 kOSKextLogIPCFlag,
330                 "Failed to copy log data for request from user space.");
331             *op_result = copyin_result;  // xxx - should we map to our own code?
332             *logDataOut = NULL;
333             *logDataLengthOut = 0;
334             goto finish;
335         }
336     }
337 
338 finish:
339     if (request) {
340         (void)vm_deallocate(kernel_map, (vm_offset_t)request, requestLengthIn);
341     }
342     if (response) {
343         /* 11981737 - clear uninitialized data in last page */
344         kmem_free(kernel_map, (vm_offset_t)response, round_page(responseLength));
345     }
346     if (logData) {
347         /* 11981737 - clear uninitialized data in last page */
348         kmem_free(kernel_map, (vm_offset_t)logData, round_page(logDataLength));
349     }
350 
351     return result;
352 }
353 
354 /*********************************************************************
355 * Gets the vm_map for the current kext
356 *********************************************************************/
357 extern vm_offset_t segPRELINKTEXTB;
358 extern unsigned long segSizePRELINKTEXT;
359 extern int kth_started;
360 extern vm_map_t g_kext_map;
361 
362 vm_map_t
363 kext_get_vm_map(kmod_info_t *info)
364 {
365     vm_map_t kext_map = NULL;
366 
367     /* Set the vm map */
368     if ((info->address >= segPRELINKTEXTB) &&
369             (info->address < (segPRELINKTEXTB + segSizePRELINKTEXT)))
370     {
371         kext_map = kernel_map;
372     } else {
373         kext_map = g_kext_map;
374     }
375 
376     return kext_map;
377 }
378 
379 
380 #if PRAGMA_MARK
381 /********************************************************************/
382 #pragma mark Weak linking support
383 /********************************************************************/
384 #endif
385 void
386 kext_weak_symbol_referenced(void)
387 {
388     panic("A kext referenced an unresolved weak symbol\n");
389 }
390 
391 const void *gOSKextUnresolved = (const void *)&kext_weak_symbol_referenced;
392 
393 #if PRAGMA_MARK
394 #pragma mark Kernel-Internal C Functions
395 #endif
396 /*********************************************************************
397 * Called from startup.c.
398 *********************************************************************/
399 void OSKextRemoveKextBootstrap(void)
400 {
401     OSKext::removeKextBootstrap();
402     return;
403 }
404 
405 #if CONFIG_DTRACE
406 /*********************************************************************
407 *********************************************************************/
408 void OSKextRegisterKextsWithDTrace(void)
409 {
410     OSKext::registerKextsWithDTrace();
411     return;
412 }
413 #endif /* CONFIG_DTRACE */
414 
415 /*********************************************************************
416 *********************************************************************/
417 void kext_dump_panic_lists(int (*printf_func)(const char * fmt, ...))
418 {
419     OSKext::printKextPanicLists(printf_func);
420     return;
421 }
422 
423 #if PRAGMA_MARK
424 #pragma mark Kmod Compatibility Functions
425 #endif
426 /*********************************************************************
427 **********************************************************************
428 *                    KMOD COMPATIBILITY FUNCTIONS                    *
429 *              (formerly in kmod.c, or C++ bridges from)             *
430 **********************************************************************
431 **********************************************************************
432 * These two functions are used in various places in the kernel, but
433 * are not exported. We might rename them at some point to start with
434 * kext_ or OSKext.
435 *
436 * kmod_panic_dump() must not be called outside of a panic context.
437 * kmod_dump_log() must not be called in a panic context.
438 *********************************************************************/
439 void
440 kmod_panic_dump(vm_offset_t * addr, unsigned int cnt)
441 {
442     extern int paniclog_append_noflush(const char *format, ...) __printflike(1,2);
443 
444     OSKext::printKextsInBacktrace(addr, cnt, &paniclog_append_noflush, 0);
445 
446     return;
447 }
448 
449 /********************************************************************/
450 void kmod_dump_log(vm_offset_t *addr, unsigned int cnt, boolean_t doUnslide);
451 
452 void
453 kmod_dump_log(
454     vm_offset_t * addr,
455     unsigned int cnt,
456     boolean_t doUnslide)
457 {
458     uint32_t flags = OSKext::kPrintKextsLock;
459     if (doUnslide) flags |= OSKext::kPrintKextsUnslide;
460     OSKext::printKextsInBacktrace(addr, cnt, &printf, flags);
461 }
462 
463 void *
464 OSKextKextForAddress(const void *addr)
465 {
466     return OSKext::kextForAddress(addr);
467 }
468 
469 
470 /*********************************************************************
471 * Compatibility implementation for kmod_get_info() host_priv routine.
472 * Only supported on old 32-bit architectures.
473 *********************************************************************/
474 
475 #if PRAGMA_MARK
476 #pragma mark Loaded Kext Summary
477 #endif
478 
479 void
480 OSKextLoadedKextSummariesUpdated(void)
481 {
482     // Do nothing.
483 }
484 
485 };
486