SUPR3HardenedMain.cpp@ 45182

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1	/* $Id: SUPR3HardenedMain.cpp 44528 2013-02-04 14:27:54Z vboxsync $ */
2	/** @file
3	* VirtualBox Support Library - Hardened main().
4	*/
5
6	/*
7	* Copyright (C) 2006-2012 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27	/*******************************************************************************
28	* Header Files *
29	*******************************************************************************/
30	#if defined(RT_OS_OS2)
31	# define INCL_BASE
32	# define INCL_ERRORS
33	# include <os2.h>
34	# include <stdio.h>
35	# include <stdlib.h>
36	# include <dlfcn.h>
37
38	#elif RT_OS_WINDOWS
39	# include <Windows.h>
40	# include <stdio.h>
41
42	#else /* UNIXes */
43	# include <iprt/types.h> /* stdint fun on darwin. */
44
45	# include <stdio.h>
46	# include <stdlib.h>
47	# include <dlfcn.h>
48	# include <limits.h>
49	# include <errno.h>
50	# include <unistd.h>
51	# include <sys/stat.h>
52	# include <sys/time.h>
53	# include <stdio.h>
54	# include <sys/types.h>
55	# if defined(RT_OS_LINUX)
56	# undef USE_LIB_PCAP /* don't depend on libcap as we had to depend on either
57	libcap1 or libcap2 */
58
59	# undef _POSIX_SOURCE
60	# include <linux/types.h> /* sys/capabilities from uek-headers require this */
61	# include <sys/capability.h>
62	# include <sys/prctl.h>
63	# ifndef CAP_TO_MASK
64	# define CAP_TO_MASK(cap) RT_BIT(cap)
65	# endif
66	# elif defined(RT_OS_FREEBSD)
67	# include <sys/param.h>
68	# include <sys/sysctl.h>
69	# elif defined(RT_OS_SOLARIS)
70	# include <priv.h>
71	# endif
72	# include <pwd.h>
73	# ifdef RT_OS_DARWIN
74	# include <mach-o/dyld.h>
75	# endif
76
77	#endif
78
79	#include <VBox/sup.h>
80	#include <VBox/err.h>
81	#include <iprt/string.h>
82	#include <iprt/initterm.h>
83	#include <iprt/param.h>
84
85	#include "SUPLibInternal.h"
86
87
88	/*******************************************************************************
89	* Defined Constants And Macros *
90	*******************************************************************************/
91	/** @def SUP_HARDENED_SUID
92	* Whether we're employing set-user-ID-on-execute in the hardening.
93	*/
94	#if !defined(RT_OS_OS2) && !defined(RT_OS_WINDOWS) && !defined(RT_OS_L4)
95	# define SUP_HARDENED_SUID
96	#else
97	# undef SUP_HARDENED_SUID
98	#endif
99
100	/** @def SUP_HARDENED_SYM
101	* Decorate a symbol that's resolved dynamically.
102	*/
103	#ifdef RT_OS_OS2
104	# define SUP_HARDENED_SYM(sym) "_" sym
105	#else
106	# define SUP_HARDENED_SYM(sym) sym
107	#endif
108
109
110	/*******************************************************************************
111	* Structures and Typedefs *
112	*******************************************************************************/
113	/** @see RTR3InitEx */
114	typedef DECLCALLBACK(int) FNRTR3INITEX(uint32_t iVersion, uint32_t fFlags, int cArgs,
115	char *papszArgs, const char pszProgramPath);
116	typedef FNRTR3INITEX *PFNRTR3INITEX;
117
118
119	/*******************************************************************************
120	* Global Variables *
121	*******************************************************************************/
122	/** The pre-init data we pass on to SUPR3 (residing in VBoxRT). */
123	static SUPPREINITDATA g_SupPreInitData;
124	/** The program executable path. */
125	static char g_szSupLibHardenedExePath[RTPATH_MAX];
126	/** The program directory path. */
127	static char g_szSupLibHardenedDirPath[RTPATH_MAX];
128
129	/** The program name. */
130	static const char *g_pszSupLibHardenedProgName;
131
132	#ifdef SUP_HARDENED_SUID
133	/** The real UID at startup. */
134	static uid_t g_uid;
135	/** The real GID at startup. */
136	static gid_t g_gid;
137	# ifdef RT_OS_LINUX
138	static uint32_t g_uCaps;
139	# endif
140	#endif
141
142
143	/*******************************************************************************
144	* Internal Functions *
145	*******************************************************************************/
146	#ifdef SUP_HARDENED_SUID
147	static void supR3HardenedMainDropPrivileges(void);
148	#endif
149	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName);
150
151
152	/**
153	* @copydoc RTPathStripFilename.
154	*/
155	static void suplibHardenedPathStripFilename(char *pszPath)
156	{
157	char *psz = pszPath;
158	char *pszLastSep = pszPath;
159
160	for (;; psz++)
161	{
162	switch (*psz)
163	{
164	/* handle separators. */
165	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
166	case ':':
167	pszLastSep = psz + 1;
168	break;
169
170	case '\\':
171	#endif
172	case '/':
173	pszLastSep = psz;
174	break;
175
176	/* the end */
177	case '\0':
178	if (pszLastSep == pszPath)
179	*pszLastSep++ = '.';
180	*pszLastSep = '\0';
181	return;
182	}
183	}
184	/* will never get here */
185	}
186
187
188	/**
189	* @copydoc RTPathFilename
190	*/
191	DECLHIDDEN(char ) supR3HardenedPathFilename(const char pszPath)
192	{
193	const char *psz = pszPath;
194	const char *pszLastComp = pszPath;
195
196	for (;; psz++)
197	{
198	switch (*psz)
199	{
200	/* handle separators. */
201	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
202	case ':':
203	pszLastComp = psz + 1;
204	break;
205
206	case '\\':
207	#endif
208	case '/':
209	pszLastComp = psz + 1;
210	break;
211
212	/* the end */
213	case '\0':
214	if (*pszLastComp)
215	return (char )(void )pszLastComp;
216	return NULL;
217	}
218	}
219
220	/* will never get here */
221	return NULL;
222	}
223
224
225	/**
226	* @copydoc RTPathAppPrivateNoArch
227	*/
228	DECLHIDDEN(int) supR3HardenedPathAppPrivateNoArch(char *pszPath, size_t cchPath)
229	{
230	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE)
231	const char *pszSrcPath = RTPATH_APP_PRIVATE;
232	size_t cchPathPrivateNoArch = strlen(pszSrcPath);
233	if (cchPathPrivateNoArch >= cchPath)
234	supR3HardenedFatal("supR3HardenedPathAppPrivateNoArch: Buffer overflow, %lu >= %lu\n",
235	(unsigned long)cchPathPrivateNoArch, (unsigned long)cchPath);
236	memcpy(pszPath, pszSrcPath, cchPathPrivateNoArch + 1);
237	return VINF_SUCCESS;
238
239	#else
240	return supR3HardenedPathExecDir(pszPath, cchPath);
241	#endif
242	}
243
244
245	/**
246	* @copydoc RTPathAppPrivateArch
247	*/
248	DECLHIDDEN(int) supR3HardenedPathAppPrivateArch(char *pszPath, size_t cchPath)
249	{
250	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH)
251	const char *pszSrcPath = RTPATH_APP_PRIVATE_ARCH;
252	size_t cchPathPrivateArch = strlen(pszSrcPath);
253	if (cchPathPrivateArch >= cchPath)
254	supR3HardenedFatal("supR3HardenedPathAppPrivateArch: Buffer overflow, %lu >= %lu\n",
255	(unsigned long)cchPathPrivateArch, (unsigned long)cchPath);
256	memcpy(pszPath, pszSrcPath, cchPathPrivateArch + 1);
257	return VINF_SUCCESS;
258
259	#else
260	return supR3HardenedPathExecDir(pszPath, cchPath);
261	#endif
262	}
263
264
265	/**
266	* @copydoc RTPathSharedLibs
267	*/
268	DECLHIDDEN(int) supR3HardenedPathSharedLibs(char *pszPath, size_t cchPath)
269	{
270	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_SHARED_LIBS)
271	const char *pszSrcPath = RTPATH_SHARED_LIBS;
272	size_t cchPathSharedLibs = strlen(pszSrcPath);
273	if (cchPathSharedLibs >= cchPath)
274	supR3HardenedFatal("supR3HardenedPathSharedLibs: Buffer overflow, %lu >= %lu\n",
275	(unsigned long)cchPathSharedLibs, (unsigned long)cchPath);
276	memcpy(pszPath, pszSrcPath, cchPathSharedLibs + 1);
277	return VINF_SUCCESS;
278
279	#else
280	return supR3HardenedPathExecDir(pszPath, cchPath);
281	#endif
282	}
283
284
285	/**
286	* @copydoc RTPathAppDocs
287	*/
288	DECLHIDDEN(int) supR3HardenedPathAppDocs(char *pszPath, size_t cchPath)
289	{
290	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_DOCS)
291	const char *pszSrcPath = RTPATH_APP_DOCS;
292	size_t cchPathAppDocs = strlen(pszSrcPath);
293	if (cchPathAppDocs >= cchPath)
294	supR3HardenedFatal("supR3HardenedPathAppDocs: Buffer overflow, %lu >= %lu\n",
295	(unsigned long)cchPathAppDocs, (unsigned long)cchPath);
296	memcpy(pszPath, pszSrcPath, cchPathAppDocs + 1);
297	return VINF_SUCCESS;
298
299	#else
300	return supR3HardenedPathExecDir(pszPath, cchPath);
301	#endif
302	}
303
304
305	/**
306	* Returns the full path to the executable.
307	*
308	* @returns IPRT status code.
309	* @param pszPath Where to store it.
310	* @param cchPath How big that buffer is.
311	*/
312	static void supR3HardenedGetFullExePath(void)
313	{
314	/*
315	* Get the program filename.
316	*
317	* Most UNIXes have no API for obtaining the executable path, but provides a symbolic
318	* link in the proc file system that tells who was exec'ed. The bad thing about this
319	* is that we have to use readlink, one of the weirder UNIX APIs.
320	*
321	* Darwin, OS/2 and Windows all have proper APIs for getting the program file name.
322	*/
323	#if defined(RT_OS_LINUX) \|\| defined(RT_OS_FREEBSD) \|\| defined(RT_OS_SOLARIS)
324	# ifdef RT_OS_LINUX
325	int cchLink = readlink("/proc/self/exe", &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
326
327	# elif defined(RT_OS_SOLARIS)
328	char szFileBuf[PATH_MAX + 1];
329	sprintf(szFileBuf, "/proc/%ld/path/a.out", (long)getpid());
330	int cchLink = readlink(szFileBuf, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
331
332	# else /* RT_OS_FREEBSD */
333	int aiName[4];
334	aiName[0] = CTL_KERN;
335	aiName[1] = KERN_PROC;
336	aiName[2] = KERN_PROC_PATHNAME;
337	aiName[3] = getpid();
338
339	size_t cbPath = sizeof(g_szSupLibHardenedExePath);
340	if (sysctl(aiName, RT_ELEMENTS(aiName), g_szSupLibHardenedExePath, &cbPath, NULL, 0) < 0)
341	supR3HardenedFatal("supR3HardenedExecDir: sysctl failed\n");
342	g_szSupLibHardenedExePath[sizeof(g_szSupLibHardenedExePath) - 1] = '\0';
343	int cchLink = strlen(g_szSupLibHardenedExePath); /* paranoid? can't we use cbPath? */
344
345	# endif
346	if (cchLink < 0 \|\| cchLink == sizeof(g_szSupLibHardenedExePath) - 1)
347	supR3HardenedFatal("supR3HardenedExecDir: couldn't read \"%s\", errno=%d cchLink=%d\n",
348	g_szSupLibHardenedExePath, errno, cchLink);
349	g_szSupLibHardenedExePath[cchLink] = '\0';
350
351	#elif defined(RT_OS_OS2) \|\| defined(RT_OS_L4)
352	_execname(g_szSupLibHardenedExePath, sizeof(g_szSupLibHardenedExePath));
353
354	#elif defined(RT_OS_DARWIN)
355	const char *pszImageName = _dyld_get_image_name(0);
356	if (!pszImageName)
357	supR3HardenedFatal("supR3HardenedExecDir: _dyld_get_image_name(0) failed\n");
358	size_t cchImageName = strlen(pszImageName);
359	if (!cchImageName \|\| cchImageName >= sizeof(g_szSupLibHardenedExePath))
360	supR3HardenedFatal("supR3HardenedExecDir: _dyld_get_image_name(0) failed, cchImageName=%d\n", cchImageName);
361	memcpy(g_szSupLibHardenedExePath, pszImageName, cchImageName + 1);
362
363	#elif defined(RT_OS_WINDOWS)
364	HMODULE hExe = GetModuleHandle(NULL);
365	if (!GetModuleFileName(hExe, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath)))
366	supR3HardenedFatal("supR3HardenedExecDir: GetModuleFileName failed, rc=%d\n", GetLastError());
367	#else
368	# error needs porting.
369	#endif
370
371	/*
372	* Strip off the filename part (RTPathStripFilename()).
373	*/
374	strcpy(g_szSupLibHardenedDirPath, g_szSupLibHardenedExePath);
375	suplibHardenedPathStripFilename(g_szSupLibHardenedDirPath);
376	}
377
378
379	#ifdef RT_OS_LINUX
380	/**
381	* Checks if we can read /proc/self/exe.
382	*
383	* This is used on linux to see if we have to call init
384	* with program path or not.
385	*
386	* @returns true / false.
387	*/
388	static bool supR3HardenedMainIsProcSelfExeAccssible(void)
389	{
390	char szPath[RTPATH_MAX];
391	int cchLink = readlink("/proc/self/exe", szPath, sizeof(szPath));
392	return cchLink != -1;
393	}
394	#endif /* RT_OS_LINUX */
395
396
397
398	/**
399	* @copydoc RTPathExecDir
400	*/
401	DECLHIDDEN(int) supR3HardenedPathExecDir(char *pszPath, size_t cchPath)
402	{
403	/*
404	* Lazy init (probably not required).
405	*/
406	if (!g_szSupLibHardenedDirPath[0])
407	supR3HardenedGetFullExePath();
408
409	/*
410	* Calc the length and check if there is space before copying.
411	*/
412	size_t cch = strlen(g_szSupLibHardenedDirPath) + 1;
413	if (cch <= cchPath)
414	{
415	memcpy(pszPath, g_szSupLibHardenedDirPath, cch + 1);
416	return VINF_SUCCESS;
417	}
418
419	supR3HardenedFatal("supR3HardenedPathExecDir: Buffer too small (%u < %u)\n", cchPath, cch);
420	return VERR_BUFFER_OVERFLOW;
421	}
422
423
424	DECLHIDDEN(void) supR3HardenedFatalMsgV(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, va_list va)
425	{
426	/*
427	* To the console first, like supR3HardenedFatalV.
428	*/
429	fprintf(stderr, "%s: Error %d in %s!\n", g_pszSupLibHardenedProgName, rc, pszWhere);
430	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
431	va_list vaCopy;
432	va_copy(vaCopy, va);
433	vfprintf(stderr, pszMsgFmt, vaCopy);
434	va_end(vaCopy);
435	fprintf(stderr, "\n");
436
437	switch (enmWhat)
438	{
439	case kSupInitOp_Driver:
440	fprintf(stderr,
441	"\n"
442	"%s: Tip! Make sure the kernel module is loaded. It may also help to reinstall VirtualBox.\n",
443	g_pszSupLibHardenedProgName);
444	break;
445
446	case kSupInitOp_IPRT:
447	case kSupInitOp_Integrity:
448	case kSupInitOp_RootCheck:
449	fprintf(stderr,
450	"\n"
451	"%s: Tip! It may help to reinstall VirtualBox.\n",
452	g_pszSupLibHardenedProgName);
453	break;
454
455	default:
456	/* no hints here */
457	break;
458	}
459
460	#ifdef SUP_HARDENED_SUID
461	/*
462	* Drop any root privileges we might be holding, this won't return
463	* if it fails but end up calling supR3HardenedFatal[V].
464	*/
465	supR3HardenedMainDropPrivileges();
466	#endif /* SUP_HARDENED_SUID */
467
468	/*
469	* Now try resolve and call the TrustedError entry point if we can
470	* find it. We'll fork before we attempt this because that way the
471	* session management in main will see us exiting immediately (if
472	* it's involved with us).
473	*/
474	#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
475	int pid = fork();
476	if (pid <= 0)
477	#endif
478	{
479	PFNSUPTRUSTEDERROR pfnTrustedError = supR3HardenedMainGetTrustedError(g_pszSupLibHardenedProgName);
480	if (pfnTrustedError)
481	pfnTrustedError(pszWhere, enmWhat, rc, pszMsgFmt, va);
482	}
483
484	/*
485	* Quit
486	*/
487	for (;;)
488	#ifdef _MSC_VER
489	exit(1);
490	#else
491	_Exit(1);
492	#endif
493	}
494
495
496	DECLHIDDEN(void) supR3HardenedFatalMsg(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, ...)
497	{
498	va_list va;
499	va_start(va, pszMsgFmt);
500	supR3HardenedFatalMsgV(pszWhere, enmWhat, rc, pszMsgFmt, va);
501	va_end(va);
502	}
503
504
505	DECLHIDDEN(void) supR3HardenedFatalV(const char *pszFormat, va_list va)
506	{
507	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
508	vfprintf(stderr, pszFormat, va);
509	for (;;)
510	#ifdef _MSC_VER
511	exit(1);
512	#else
513	_Exit(1);
514	#endif
515	}
516
517
518	DECLHIDDEN(void) supR3HardenedFatal(const char *pszFormat, ...)
519	{
520	va_list va;
521	va_start(va, pszFormat);
522	supR3HardenedFatalV(pszFormat, va);
523	va_end(va);
524	}
525
526
527	DECLHIDDEN(int) supR3HardenedErrorV(int rc, bool fFatal, const char *pszFormat, va_list va)
528	{
529	if (fFatal)
530	supR3HardenedFatalV(pszFormat, va);
531
532	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
533	vfprintf(stderr, pszFormat, va);
534	return rc;
535	}
536
537
538	DECLHIDDEN(int) supR3HardenedError(int rc, bool fFatal, const char *pszFormat, ...)
539	{
540	va_list va;
541	va_start(va, pszFormat);
542	supR3HardenedErrorV(rc, fFatal, pszFormat, va);
543	va_end(va);
544	return rc;
545	}
546
547
548	/**
549	* Wrapper around snprintf which will throw a fatal error on buffer overflow.
550	*
551	* @returns Number of chars in the result string.
552	* @param pszDst The destination buffer.
553	* @param cchDst The size of the buffer.
554	* @param pszFormat The format string.
555	* @param ... Format arguments.
556	*/
557	static size_t supR3HardenedStrPrintf(char pszDst, size_t cchDst, const char pszFormat, ...)
558	{
559	va_list va;
560	va_start(va, pszFormat);
561	#ifdef _MSC_VER
562	int cch = _vsnprintf(pszDst, cchDst, pszFormat, va);
563	#else
564	int cch = vsnprintf(pszDst, cchDst, pszFormat, va);
565	#endif
566	va_end(va);
567	if ((unsigned)cch >= cchDst \|\| cch < 0)
568	supR3HardenedFatal("supR3HardenedStrPrintf: buffer overflow, %d >= %lu\n", cch, (long)cchDst);
569	return cch;
570	}
571
572
573	/**
574	* Attempts to open /dev/vboxdrv (or equvivalent).
575	*
576	* @remarks This function will not return on failure.
577	*/
578	static void supR3HardenedMainOpenDevice(void)
579	{
580	int rc = suplibOsInit(&g_SupPreInitData.Data, false /fPreInit/, true /fUnrestricted/);
581	if (RT_SUCCESS(rc))
582	return;
583
584	switch (rc)
585	{
586	/** @todo better messages! */
587	case VERR_VM_DRIVER_NOT_INSTALLED:
588	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
589	"Kernel driver not installed");
590	case VERR_VM_DRIVER_NOT_ACCESSIBLE:
591	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
592	"Kernel driver not accessible");
593	case VERR_VM_DRIVER_LOAD_ERROR:
594	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
595	"VERR_VM_DRIVER_LOAD_ERROR");
596	case VERR_VM_DRIVER_OPEN_ERROR:
597	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
598	"VERR_VM_DRIVER_OPEN_ERROR");
599	case VERR_VM_DRIVER_VERSION_MISMATCH:
600	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
601	"Kernel driver version mismatch");
602	case VERR_ACCESS_DENIED:
603	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
604	"VERR_ACCESS_DENIED");
605	case VERR_NO_MEMORY:
606	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
607	"Kernel memory allocation/mapping failed");
608	default:
609	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
610	"Unknown rc=%d", rc);
611	}
612	}
613
614
615	#ifdef SUP_HARDENED_SUID
616
617	/**
618	* Grabs extra non-root capabilities / privileges that we might require.
619	*
620	* This is currently only used for being able to do ICMP from the NAT engine.
621	*
622	* @note We still have root privileges at the time of this call.
623	*/
624	static void supR3HardenedMainGrabCapabilites(void)
625	{
626	# if defined(RT_OS_LINUX)
627	/*
628	* We are about to drop all our privileges. Remove all capabilities but
629	* keep the cap_net_raw capability for ICMP sockets for the NAT stack.
630	*/
631	if (g_uCaps != 0)
632	{
633	# ifdef USE_LIB_PCAP
634	/* XXX cap_net_bind_service */
635	if (!cap_set_proc(cap_from_text("all-eip cap_net_raw+ep")))
636	prctl(PR_SET_KEEPCAPS, 1 /keep=/, 0, 0, 0);
637	prctl(PR_SET_DUMPABLE, 1 /dump/, 0, 0, 0);
638	# else
639	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
640	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
641	memset(hdr, 0, sizeof(*hdr));
642	hdr->version = _LINUX_CAPABILITY_VERSION;
643	memset(cap, 0, sizeof(*cap));
644	cap->effective = g_uCaps;
645	cap->permitted = g_uCaps;
646	if (!capset(hdr, cap))
647	prctl(PR_SET_KEEPCAPS, 1 /keep/, 0, 0, 0);
648	prctl(PR_SET_DUMPABLE, 1 /dump/, 0, 0, 0);
649	# endif /* !USE_LIB_PCAP */
650	}
651
652	# elif defined(RT_OS_SOLARIS)
653	/*
654	* Add net_icmpaccess privilege to effective privileges and limit
655	* permitted privileges before completely dropping root privileges.
656	* This requires dropping root privileges temporarily to get the normal
657	* user's privileges.
658	*/
659	seteuid(g_uid);
660	priv_set_t *pPrivEffective = priv_allocset();
661	priv_set_t *pPrivNew = priv_allocset();
662	if (pPrivEffective && pPrivNew)
663	{
664	int rc = getppriv(PRIV_EFFECTIVE, pPrivEffective);
665	seteuid(0);
666	if (!rc)
667	{
668	priv_copyset(pPrivEffective, pPrivNew);
669	rc = priv_addset(pPrivNew, PRIV_NET_ICMPACCESS);
670	if (!rc)
671	{
672	/* Order is important, as one can't set a privilege which is
673	* not in the permitted privilege set. */
674	rc = setppriv(PRIV_SET, PRIV_EFFECTIVE, pPrivNew);
675	if (rc)
676	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set effective privilege set.\n");
677	rc = setppriv(PRIV_SET, PRIV_PERMITTED, pPrivNew);
678	if (rc)
679	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set permitted privilege set.\n");
680	}
681	else
682	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to add NET_ICMPACCESS privilege.\n");
683	}
684	}
685	else
686	{
687	/* for memory allocation failures just continue */
688	seteuid(0);
689	}
690
691	if (pPrivEffective)
692	priv_freeset(pPrivEffective);
693	if (pPrivNew)
694	priv_freeset(pPrivNew);
695	# endif
696	}
697
698	/*
699	* Look at the environment for some special options.
700	*/
701	static void supR3GrabOptions(void)
702	{
703	const char *pszOpt;
704
705	# ifdef RT_OS_LINUX
706	g_uCaps = 0;
707
708	/*
709	* Do _not_ perform any capability-related system calls for root processes
710	* (leaving g_uCaps at 0).
711	* (Hint: getuid gets the real user id, not the effective.)
712	*/
713	if (getuid() != 0)
714	{
715	/*
716	* CAP_NET_RAW.
717	* Default: enabled.
718	* Can be disabled with 'export VBOX_HARD_CAP_NET_RAW=0'.
719	*/
720	pszOpt = getenv("VBOX_HARD_CAP_NET_RAW");
721	if ( !pszOpt
722	\|\| memcmp(pszOpt, "0", sizeof("0")) != 0)
723	g_uCaps = CAP_TO_MASK(CAP_NET_RAW);
724
725	/*
726	* CAP_NET_BIND_SERVICE.
727	* Default: disabled.
728	* Can be enabled with 'export VBOX_HARD_CAP_NET_BIND_SERVICE=1'.
729	*/
730	pszOpt = getenv("VBOX_HARD_CAP_NET_BIND_SERVICE");
731	if ( pszOpt
732	&& memcmp(pszOpt, "0", sizeof("0")) != 0)
733	g_uCaps \|= CAP_TO_MASK(CAP_NET_BIND_SERVICE);
734	}
735	# endif
736	}
737
738	/**
739	* Drop any root privileges we might be holding.
740	*/
741	static void supR3HardenedMainDropPrivileges(void)
742	{
743	/*
744	* Try use setre[ug]id since this will clear the save uid/gid and thus
745	* leave fewer traces behind that libs like GTK+ may pick up.
746	*/
747	uid_t euid, ruid, suid;
748	gid_t egid, rgid, sgid;
749	# if defined(RT_OS_DARWIN)
750	/* The really great thing here is that setreuid isn't available on
751	OS X 10.4, libc emulates it. While 10.4 have a slightly different and
752	non-standard setuid implementation compared to 10.5, the following
753	works the same way with both version since we're super user (10.5 req).
754	The following will set all three variants of the group and user IDs. */
755	setgid(g_gid);
756	setuid(g_uid);
757	euid = geteuid();
758	ruid = suid = getuid();
759	egid = getegid();
760	rgid = sgid = getgid();
761
762	# elif defined(RT_OS_SOLARIS)
763	/* Solaris doesn't have setresuid, but the setreuid interface is BSD
764	compatible and will set the saved uid to euid when we pass it a ruid
765	that isn't -1 (which we do). */
766	setregid(g_gid, g_gid);
767	setreuid(g_uid, g_uid);
768	euid = geteuid();
769	ruid = suid = getuid();
770	egid = getegid();
771	rgid = sgid = getgid();
772
773	# else
774	/* This is the preferred one, full control no questions about semantics.
775	PORTME: If this isn't work, try join one of two other gangs above. */
776	setresgid(g_gid, g_gid, g_gid);
777	setresuid(g_uid, g_uid, g_uid);
778	if (getresuid(&ruid, &euid, &suid) != 0)
779	{
780	euid = geteuid();
781	ruid = suid = getuid();
782	}
783	if (getresgid(&rgid, &egid, &sgid) != 0)
784	{
785	egid = getegid();
786	rgid = sgid = getgid();
787	}
788	# endif
789
790
791	/* Check that it worked out all right. */
792	if ( euid != g_uid
793	\|\| ruid != g_uid
794	\|\| suid != g_uid
795	\|\| egid != g_gid
796	\|\| rgid != g_gid
797	\|\| sgid != g_gid)
798	supR3HardenedFatal("SUPR3HardenedMain: failed to drop root privileges!"
799	" (euid=%d ruid=%d suid=%d egid=%d rgid=%d sgid=%d; wanted uid=%d and gid=%d)\n",
800	euid, ruid, suid, egid, rgid, sgid, g_uid, g_gid);
801
802	# if RT_OS_LINUX
803	/*
804	* Re-enable the cap_net_raw capability which was disabled during setresuid.
805	*/
806	if (g_uCaps != 0)
807	{
808	# ifdef USE_LIB_PCAP
809	/** @todo Warn if that does not work? */
810	/* XXX cap_net_bind_service */
811	cap_set_proc(cap_from_text("cap_net_raw+ep"));
812	# else
813	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
814	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
815	memset(hdr, 0, sizeof(*hdr));
816	hdr->version = _LINUX_CAPABILITY_VERSION;
817	memset(cap, 0, sizeof(*cap));
818	cap->effective = g_uCaps;
819	cap->permitted = g_uCaps;
820	/** @todo Warn if that does not work? */
821	capset(hdr, cap);
822	# endif /* !USE_LIB_PCAP */
823	}
824	# endif
825	}
826
827	#endif /* SUP_HARDENED_SUID */
828
829	/**
830	* Loads the VBoxRT DLL/SO/DYLIB, hands it the open driver,
831	* and calls RTR3InitEx.
832	*
833	* @param fFlags The SUPR3HardenedMain fFlags argument, passed to supR3PreInit.
834	*
835	* @remarks VBoxRT contains both IPRT and SUPR3.
836	* @remarks This function will not return on failure.
837	*/
838	static void supR3HardenedMainInitRuntime(uint32_t fFlags)
839	{
840	/*
841	* Construct the name.
842	*/
843	char szPath[RTPATH_MAX];
844	supR3HardenedPathSharedLibs(szPath, sizeof(szPath) - sizeof("/VBoxRT" SUPLIB_DLL_SUFF));
845	strcat(szPath, "/VBoxRT" SUPLIB_DLL_SUFF);
846
847	/*
848	* Open it and resolve the symbols.
849	*/
850	#if defined(RT_OS_WINDOWS)
851	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
852	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
853	if (!hMod)
854	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
855	"LoadLibraryEx(\"%s\",,) failed (rc=%d)",
856	szPath, GetLastError());
857	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)GetProcAddress(hMod, SUP_HARDENED_SYM("RTR3InitEx"));
858	if (!pfnRTInitEx)
859	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
860	"Entrypoint \"RTR3InitEx\" not found in \"%s\" (rc=%d)",
861	szPath, GetLastError());
862
863	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)GetProcAddress(hMod, SUP_HARDENED_SYM("supR3PreInit"));
864	if (!pfnSUPPreInit)
865	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
866	"Entrypoint \"supR3PreInit\" not found in \"%s\" (rc=%d)",
867	szPath, GetLastError());
868
869	#else
870	/* the dlopen crowd */
871	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
872	if (!pvMod)
873	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
874	"dlopen(\"%s\",) failed: %s",
875	szPath, dlerror());
876	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("RTR3InitEx"));
877	if (!pfnRTInitEx)
878	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
879	"Entrypoint \"RTR3InitEx\" not found in \"%s\"!\ndlerror: %s",
880	szPath, dlerror());
881	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("supR3PreInit"));
882	if (!pfnSUPPreInit)
883	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
884	"Entrypoint \"supR3PreInit\" not found in \"%s\"!\ndlerror: %s",
885	szPath, dlerror());
886	#endif
887
888	/*
889	* Make the calls.
890	*/
891	supR3HardenedGetPreInitData(&g_SupPreInitData);
892	int rc = pfnSUPPreInit(&g_SupPreInitData, fFlags);
893	if (RT_FAILURE(rc))
894	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
895	"supR3PreInit failed with rc=%d", rc);
896	const char *pszExePath = NULL;
897	#ifdef RT_OS_LINUX
898	if (!supR3HardenedMainIsProcSelfExeAccssible())
899	pszExePath = g_szSupLibHardenedExePath;
900	#endif
901	rc = pfnRTInitEx(RTR3INIT_VER_1,
902	fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV ? 0 : RTR3INIT_FLAGS_SUPLIB,
903	0 /cArgs/, NULL /papszArgs/, pszExePath);
904	if (RT_FAILURE(rc))
905	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
906	"RTR3InitEx failed with rc=%d", rc);
907	}
908
909
910	/**
911	* Loads the DLL/SO/DYLIB containing the actual program and
912	* resolves the TrustedError symbol.
913	*
914	* This is very similar to supR3HardenedMainGetTrustedMain().
915	*
916	* @returns Pointer to the trusted error symbol if it is exported, NULL
917	* and no error messages otherwise.
918	* @param pszProgName The program name.
919	*/
920	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName)
921	{
922	/*
923	* Construct the name.
924	*/
925	char szPath[RTPATH_MAX];
926	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
927	size_t cch = strlen(szPath);
928	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
929
930	/*
931	* Open it and resolve the symbol.
932	*/
933	#if defined(RT_OS_WINDOWS)
934	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
935	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
936	if (!hMod)
937	return NULL;
938	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedError"));
939	if (!pfn)
940	return NULL;
941	return (PFNSUPTRUSTEDERROR)pfn;
942
943	#else
944	/* the dlopen crowd */
945	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
946	if (!pvMod)
947	return NULL;
948	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedError"));
949	if (!pvSym)
950	return NULL;
951	return (PFNSUPTRUSTEDERROR)(uintptr_t)pvSym;
952	#endif
953	}
954
955
956	/**
957	* Loads the DLL/SO/DYLIB containing the actual program and
958	* resolves the TrustedMain symbol.
959	*
960	* @returns Pointer to the trusted main of the actual program.
961	* @param pszProgName The program name.
962	* @remarks This function will not return on failure.
963	*/
964	static PFNSUPTRUSTEDMAIN supR3HardenedMainGetTrustedMain(const char *pszProgName)
965	{
966	/*
967	* Construct the name.
968	*/
969	char szPath[RTPATH_MAX];
970	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
971	size_t cch = strlen(szPath);
972	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
973
974	/*
975	* Open it and resolve the symbol.
976	*/
977	#if defined(RT_OS_WINDOWS)
978	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
979	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
980	if (!hMod)
981	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: LoadLibraryEx(\"%s\",,) failed, rc=%d\n",
982	szPath, GetLastError());
983	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedMain"));
984	if (!pfn)
985	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\" (rc=%d)\n",
986	szPath, GetLastError());
987	return (PFNSUPTRUSTEDMAIN)pfn;
988
989	#else
990	/* the dlopen crowd */
991	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
992	if (!pvMod)
993	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: dlopen(\"%s\",) failed: %s\n",
994	szPath, dlerror());
995	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedMain"));
996	if (!pvSym)
997	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\"!\ndlerror: %s\n",
998	szPath, dlerror());
999	return (PFNSUPTRUSTEDMAIN)(uintptr_t)pvSym;
1000	#endif
1001	}
1002
1003
1004	/**
1005	* Secure main.
1006	*
1007	* This is used for the set-user-ID-on-execute binaries on unixy systems
1008	* and when using the open-vboxdrv-via-root-service setup on Windows.
1009	*
1010	* This function will perform the integrity checks of the VirtualBox
1011	* installation, open the support driver, open the root service (later),
1012	* and load the DLL corresponding to \a pszProgName and execute its main
1013	* function.
1014	*
1015	* @returns Return code appropriate for main().
1016	*
1017	* @param pszProgName The program name. This will be used to figure out which
1018	* DLL/SO/DYLIB to load and execute.
1019	* @param fFlags Flags.
1020	* @param argc The argument count.
1021	* @param argv The argument vector.
1022	* @param envp The environment vector.
1023	*/
1024	DECLHIDDEN(int) SUPR3HardenedMain(const char pszProgName, uint32_t fFlags, int argc, char argv, char *envp)
1025	{
1026	/*
1027	* Note! At this point there is no IPRT, so we will have to stick
1028	* to basic CRT functions that everyone agree upon.
1029	*/
1030	g_pszSupLibHardenedProgName = pszProgName;
1031	g_SupPreInitData.u32Magic = SUPPREINITDATA_MAGIC;
1032	g_SupPreInitData.Data.hDevice = SUP_HDEVICE_NIL;
1033	g_SupPreInitData.u32EndMagic = SUPPREINITDATA_MAGIC;
1034
1035	#ifdef SUP_HARDENED_SUID
1036	# ifdef RT_OS_LINUX
1037	/*
1038	* On linux we have to make sure the path is initialized because we
1039	* might not be able to access /proc/self/exe after the seteuid call.
1040	*/
1041	supR3HardenedGetFullExePath();
1042
1043	# endif
1044
1045	/*
1046	* Grab any options from the environment.
1047	*/
1048	supR3GrabOptions();
1049
1050	/*
1051	* Check that we're root, if we aren't then the installation is butchered.
1052	*/
1053	g_uid = getuid();
1054	g_gid = getgid();
1055	if (geteuid() != 0 /* root */)
1056	supR3HardenedFatalMsg("SUPR3HardenedMain", kSupInitOp_RootCheck, VERR_PERMISSION_DENIED,
1057	"Effective UID is not root (euid=%d egid=%d uid=%d gid=%d)",
1058	geteuid(), getegid(), g_uid, g_gid);
1059	#endif
1060
1061	/*
1062	* Validate the installation.
1063	*/
1064	supR3HardenedVerifyAll(true /* fFatal /, false / fLeaveFilesOpen */, pszProgName);
1065
1066	/*
1067	* Open the vboxdrv device.
1068	*/
1069	if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV))
1070	supR3HardenedMainOpenDevice();
1071
1072	/*
1073	* Open the root service connection.
1074	*/
1075	//if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_SVC))
1076	//supR3HardenedMainOpenService(&g_SupPreInitData, true /* fFatal */);
1077
1078	#ifdef SUP_HARDENED_SUID
1079	/*
1080	* Grab additional capabilities / privileges.
1081	*/
1082	supR3HardenedMainGrabCapabilites();
1083
1084	/*
1085	* Drop any root privileges we might be holding (won't return on failure)
1086	*/
1087	supR3HardenedMainDropPrivileges();
1088	#endif
1089
1090	/*
1091	* Load the IPRT, hand the SUPLib part the open driver and
1092	* call RTR3InitEx.
1093	*/
1094	supR3HardenedMainInitRuntime(fFlags);
1095
1096	/*
1097	* Load the DLL/SO/DYLIB containing the actual program
1098	* and pass control to it.
1099	*/
1100	PFNSUPTRUSTEDMAIN pfnTrustedMain = supR3HardenedMainGetTrustedMain(pszProgName);
1101	return pfnTrustedMain(argc, argv, envp);
1102	}
1103

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source: vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp@ 45182

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