This is xnu-8019. See this file in:
/*
 * Copyright (c) 2008-2016 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

extern "C" {
#include <libkern/OSKextLibPrivate.h>
#include <libkern/mkext.h>
};

#include <libkern/c++/OSContainers.h>
#include <libkern/c++/OSKext.h>
#include <libkern/OSKextLib.h>
#include <libkern/OSKextLibPrivate.h>

extern "C" {
#if PRAGMA_MARK
#pragma mark C-based kext interface (loading/loaded kexts only)
#endif
/*********************************************************************
*********************************************************************/
kern_return_t
OSKextLoadKextWithIdentifier(const char * bundle_id)
{
	return OSKext::loadKextWithIdentifier(bundle_id);
}

uint32_t OSKextGetLoadTagForIdentifier(const char * kextIdentifier);
/*********************************************************************
*********************************************************************/
uint32_t
OSKextGetLoadTagForIdentifier(const char * kextIdentifier)
{
	uint32_t result  = kOSKextInvalidLoadTag;
	OSKext * theKext = NULL; // must release

	if (!kextIdentifier) {
		goto finish;
	}

	theKext = OSKext::lookupKextWithIdentifier(kextIdentifier);
	if (theKext && theKext->isLoaded()) {
		result = theKext->getLoadTag();
	}
finish:
	if (theKext) {
		theKext->release();
	}
	return result;
}

/*********************************************************************
*********************************************************************/

// FIXME: Implementation of this function is hidden from the static analyzer.
// The analyzer is worried about the lack of release and suggests
// refactoring the code into the typical non-owning container pattern.
// Feel free to remove the #ifndef and address the warning!
#ifndef __clang_analyzer__
OSReturn
OSKextRetainKextWithLoadTag(uint32_t loadTag)
{
	OSReturn   result = kOSKextReturnNotFound;
	OSKext   * theKext = NULL;// do not release; as this function is a retain

	if (loadTag == kOSKextInvalidLoadTag) {
		result = kOSKextReturnInvalidArgument;
		goto finish;
	}
	theKext = OSKext::lookupKextWithLoadTag(loadTag);
	if (theKext) {
		result = kOSReturnSuccess;

		OSKextLog(theKext,
		    kOSKextLogDebugLevel |
		    kOSKextLogKextBookkeepingFlag,
		    "Kext %s (load tag %d) has been retained.",
		    theKext->getIdentifierCString(),
		    loadTag);

		/* Call this after so a log message about autounload comes second.
		 */
		theKext->setAutounloadEnabled(true);
	} else {
		OSKextLog(theKext,
		    kOSKextLogErrorLevel |
		    kOSKextLogKextBookkeepingFlag,
		    "Can't retain kext with load tag %d - no such kext is loaded.",
		    loadTag);
	}
finish:
	return result;
}
#endif // __clang_analyzer__

/*********************************************************************
*********************************************************************/

// FIXME: Implementation of this function is hidden from the static analyzer.
// The analyzer is worried about the double release and suggests
// refactoring the code into the typical non-owning container pattern.
// Feel free to remove the #ifndef and address the warning!
#ifndef __clang_analyzer__
OSReturn
OSKextReleaseKextWithLoadTag(uint32_t loadTag)
{
	OSReturn result  = kOSKextReturnNotFound;
	OSKext * theKext = NULL; // must release twice!

	if (loadTag == kOSKextInvalidLoadTag) {
		result = kOSKextReturnInvalidArgument;
		goto finish;
	}
	theKext = OSKext::lookupKextWithLoadTag(loadTag);
	if (theKext) {
		result = kOSReturnSuccess;
		OSKext::considerUnloads(); // schedule autounload pass
		theKext->release(); // do the release the caller wants
		theKext->release(); // now do the release on the lookup
		OSKextLog(theKext,
		    kOSKextLogDebugLevel |
		    kOSKextLogKextBookkeepingFlag,
		    "Kext %s (load tag %d) has been released.",
		    theKext->getIdentifierCString(),
		    loadTag);
	} else {
		OSKextLog(theKext,
		    kOSKextLogErrorLevel |
		    kOSKextLogKextBookkeepingFlag,
		    "Can't release kext with load tag %d - no such kext is loaded.",
		    loadTag);
	}

	// xxx - should I check that the refcount of the OSKext is above the lower bound?
	// xxx - do we want a OSKextGetRetainCountOfKextWithLoadTag()?
finish:
	return result;
}
#endif // __clang_analyzer__

/*********************************************************************
* Not to be called by the kext being unloaded!
*********************************************************************/
OSReturn
OSKextUnloadKextWithLoadTag(uint32_t loadTag)
{
	return OSKext::removeKextWithLoadTag(loadTag,
	           /* terminateServicesAndRemovePersonalitiesFlag */ false);
}


#if PRAGMA_MARK
#pragma mark Kext Requests
#endif
/*********************************************************************
* Kext Requests
*********************************************************************/
OSReturn
OSKextRequestResource(
	const char                    * kextIdentifier,
	const char                    * resourceName,
	OSKextRequestResourceCallback   callback,
	void                          * context,
	OSKextRequestTag              * requestTagOut)
{
	return OSKext::requestResource(kextIdentifier, resourceName,
	           callback, context, requestTagOut);
}

/*********************************************************************
*********************************************************************/
OSReturn
OSKextCancelRequest(
	OSKextRequestTag    requestTag,
	void             ** contextOut)
{
	return OSKext::cancelRequest(requestTag, contextOut);
}

#if PRAGMA_MARK
#pragma mark MIG Functions & Wrappers
#endif
/*********************************************************************
* IMPORTANT: vm_map_copyout_size() consumes the requestIn copy
* object on success. Therefore once it has been invoked successfully,
* this routine *must* return KERN_SUCCESS, regardless of our actual
* result. Our contract with the caller is that requestIn must be
* caller-deallocated if we return an error. We use op_result to return
* the real result of our work.
*********************************************************************/
kern_return_t
kext_request(
	host_priv_t                             hostPriv,
	/* in only */ uint32_t                 clientLogSpec,
	/* in only */ vm_offset_t              requestIn,
	/* in only */ mach_msg_type_number_t   requestLengthIn,
	/* out only */ vm_offset_t            * responseOut,
	/* out only */ mach_msg_type_number_t * responseLengthOut,
	/* out only */ vm_offset_t            * logDataOut,
	/* out only */ mach_msg_type_number_t * logDataLengthOut,
	/* out only */ kern_return_t          * op_result)
{
	kern_return_t     result          = KERN_FAILURE;
	vm_map_address_t  map_addr        = 0; // do not free/deallocate
	char            * request         = NULL;// must vm_deallocate

	mkext2_header   * mkextHeader     = NULL;// do not release
	bool              isMkext         = false;

	char            * response        = NULL;// must kmem_free
	uint32_t          responseLength  = 0;
	char            * logData         = NULL;// must kmem_free
	uint32_t          logDataLength   = 0;

	/* MIG doesn't pass "out" parameters as empty, so clear them immediately
	 * just in case, or MIG will try to copy out bogus data.
	 */
	*op_result = KERN_FAILURE;
	*responseOut = 0;
	*responseLengthOut = 0;
	*logDataOut = 0;
	*logDataLengthOut = 0;

	/* Check for input. Don't discard what isn't there, though.
	 */
	if (!requestLengthIn || !requestIn) {
		OSKextLog(/* kext */ NULL,
		    kOSKextLogErrorLevel |
		    kOSKextLogIPCFlag,
		    "Invalid request from user space (no data).");
		*op_result = KERN_INVALID_ARGUMENT;
		goto finish;
	}

	result = vm_map_copyout_size(kernel_map, &map_addr, (vm_map_copy_t)requestIn, requestLengthIn);
	if (result != KERN_SUCCESS) {
		OSKextLog(/* kext */ NULL,
		    kOSKextLogErrorLevel |
		    kOSKextLogIPCFlag,
		    "vm_map_copyout() failed for request from user space.");
		/*
		 * If we return an error it is our caller's responsibility to
		 * deallocate the requestIn copy object, so do not deallocate it
		 * here. See comment above.
		 */
		goto finish;
	}
	request = CAST_DOWN(char *, map_addr);

	/* Check if request is an mkext; this is always a load request
	 * and requires root access. If it isn't an mkext, see if it's
	 * an XML request, and check the request to see if that requires
	 * root access.
	 */
	if (requestLengthIn > sizeof(mkext2_header)) {
		mkextHeader = (mkext2_header *)request;
		if (MKEXT_GET_MAGIC(mkextHeader) == MKEXT_MAGIC &&
		    MKEXT_GET_SIGNATURE(mkextHeader) == MKEXT_SIGN) {
			isMkext = true;
		}
	}

	if (isMkext) {
#if defined(SECURE_KERNEL) || !CONFIG_KXLD
		// xxx - something tells me if we have a secure kernel we don't even
		// xxx - want to log a message here. :-)
		*op_result = KERN_NOT_SUPPORTED;
		goto finish;
#else
		// xxx - can we find out if calling task is kextd?
		// xxx - can we find the name of the calling task?
		if (hostPriv == HOST_PRIV_NULL) {
			OSKextLog(/* kext */ NULL,
			    kOSKextLogErrorLevel |
			    kOSKextLogLoadFlag | kOSKextLogIPCFlag,
			    "Attempt by non-root process to load a kext.");
			*op_result = kOSKextReturnNotPrivileged;
			goto finish;
		}

		*op_result = OSKext::loadFromMkext((OSKextLogSpec)clientLogSpec,
		    request, requestLengthIn,
		    &logData, &logDataLength);

#endif /* defined(SECURE_KERNEL) */
	} else {
		/* If the request isn't an mkext, then is should be XML. Parse it
		 * if possible and hand the request over to OSKext.
		 */
		*op_result = OSKext::handleRequest(hostPriv,
		    (OSKextLogSpec)clientLogSpec,
		    request, requestLengthIn,
		    &response, &responseLength,
		    &logData, &logDataLength);
	}

	if (response && responseLength > 0) {
		kern_return_t copyin_result;

		copyin_result = vm_map_copyin(kernel_map,
		    CAST_USER_ADDR_T(response), responseLength,
		    /* src_destroy */ false, (vm_map_copy_t *)responseOut);
		if (copyin_result == KERN_SUCCESS) {
			*responseLengthOut = responseLength;
		} else {
			OSKextLog(/* kext */ NULL,
			    kOSKextLogErrorLevel |
			    kOSKextLogIPCFlag,
			    "Failed to copy response to request from user space.");
			*op_result = copyin_result; // xxx - should we map to our own code?
			*responseOut = 0;
			*responseLengthOut = 0;
			goto finish;
		}
	}

	if (logData && logDataLength > 0) {
		kern_return_t copyin_result;

		copyin_result = vm_map_copyin(kernel_map,
		    CAST_USER_ADDR_T(logData), logDataLength,
		    /* src_destroy */ false, (vm_map_copy_t *)logDataOut);
		if (copyin_result == KERN_SUCCESS) {
			*logDataLengthOut = logDataLength;
		} else {
			OSKextLog(/* kext */ NULL,
			    kOSKextLogErrorLevel |
			    kOSKextLogIPCFlag,
			    "Failed to copy log data for request from user space.");
			*op_result = copyin_result; // xxx - should we map to our own code?
			*logDataOut = 0;
			*logDataLengthOut = 0;
			goto finish;
		}
	}

finish:
	if (request) {
		(void)vm_deallocate(kernel_map, (vm_offset_t)request, requestLengthIn);
	}
	if (response) {
		/* 11981737 - clear uninitialized data in last page */
		kmem_free(kernel_map, (vm_offset_t)response, round_page(responseLength));
	}
	if (logData) {
		/* 11981737 - clear uninitialized data in last page */
		kmem_free(kernel_map, (vm_offset_t)logData, round_page(logDataLength));
	}

	return result;
}

/*********************************************************************
* Gets the vm_map for the current kext
*********************************************************************/
extern vm_offset_t segPRELINKTEXTB;
extern vm_offset_t segLINKB;
extern unsigned long segSizePRELINKTEXT;
extern vm_map_t g_kext_map;

vm_map_t
kext_get_vm_map(kmod_info_t *info)
{
	vm_map_t kext_map = NULL;
	kc_format_t kcformat;

	if (PE_get_primary_kc_format(&kcformat) && kcformat == KCFormatFileset) {
		/* Check if the kext is from the boot KC */
		assert(segLINKB >= (segPRELINKTEXTB + segSizePRELINKTEXT));
		if ((info->address >= segPRELINKTEXTB) &&
		    (info->address < segLINKB)) {
			kext_map = kernel_map;
		} else {
			kext_map = g_kext_map;
		}
	} else {
		if ((info->address >= segPRELINKTEXTB) &&
		    (info->address < (segPRELINKTEXTB + segSizePRELINKTEXT))) {
			kext_map = kernel_map;
		} else {
			kext_map = g_kext_map;
		}
	}

	return kext_map;
}


#if PRAGMA_MARK
/********************************************************************/
#pragma mark Weak linking support
/********************************************************************/
#endif
void
kext_weak_symbol_referenced(void)
{
	panic("A kext referenced an unresolved weak symbol");
}

const void * const gOSKextUnresolved = (const void *)&kext_weak_symbol_referenced;

#if PRAGMA_MARK
#pragma mark Kernel-Internal C Functions
#endif
/*********************************************************************
* Called from startup.c.
*********************************************************************/
void
OSKextRemoveKextBootstrap(void)
{
	OSKext::removeKextBootstrap();
	return;
}

#if CONFIG_DTRACE
/*********************************************************************
*********************************************************************/
void
OSKextRegisterKextsWithDTrace(void)
{
	OSKext::registerKextsWithDTrace();
	return;
}
#endif /* CONFIG_DTRACE */

/*********************************************************************
*********************************************************************/
void
kext_dump_panic_lists(int (*printf_func)(const char * fmt, ...))
{
	OSKext::printKextPanicLists(printf_func);
	return;
}

#if PRAGMA_MARK
#pragma mark Kmod Compatibility Functions
#endif
/*********************************************************************
**********************************************************************
*                    KMOD COMPATIBILITY FUNCTIONS                    *
*              (formerly in kmod.c, or C++ bridges from)             *
**********************************************************************
**********************************************************************
* These two functions are used in various places in the kernel, but
* are not exported. We might rename them at some point to start with
* kext_ or OSKext.
*
* kmod_panic_dump() must not be called outside of a panic context.
* kmod_dump_log() must not be called in a panic context.
*********************************************************************/
void
kmod_panic_dump(vm_offset_t * addr, unsigned int cnt)
{
	extern int paniclog_append_noflush(const char *format, ...) __printflike(1, 2);

	OSKext::printKextsInBacktrace(addr, cnt, &paniclog_append_noflush, 0);

	return;
}

/********************************************************************/
void kmod_dump_log(vm_offset_t *addr, unsigned int cnt, boolean_t doUnslide);

void
kmod_dump_log(
	vm_offset_t * addr,
	unsigned int cnt,
	boolean_t doUnslide)
{
	uint32_t flags = OSKext::kPrintKextsLock;
	if (doUnslide) {
		flags |= OSKext::kPrintKextsUnslide;
	}
	OSKext::printKextsInBacktrace(addr, cnt, &printf, flags);
}

void *
OSKextKextForAddress(const void *addr)
{
	return OSKext::kextForAddress(addr);
}


/*********************************************************************
* Compatibility implementation for kmod_get_info() host_priv routine.
* Only supported on old 32-bit architectures.
*********************************************************************/

#if PRAGMA_MARK
#pragma mark Loaded Kext Summary
#endif

void
OSKextLoadedKextSummariesUpdated(void)
{
	// Do nothing.
}
};