SUPR3HardenedMain.cpp@ 17827

Last change on this file since 17827 was 16067, checked in by vboxsync, 16 years ago
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1	/* $Id: SUPR3HardenedMain.cpp 16067 2009-01-20 07:52:25Z vboxsync $ */
2	/** @file
3	* VirtualBox Support Library - Hardened main().
4	*/
5
6	/*
7	* Copyright (C) 2006-2008 Sun Microsystems, Inc.
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	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31	/*******************************************************************************
32	* Header Files *
33	*******************************************************************************/
34	#if defined(RT_OS_OS2)
35	# define INCL_BASE
36	# define INCL_ERRORS
37	# include <os2.h>
38	# include <stdio.h>
39	# include <stdlib.h>
40	# include <dlfcn.h>
41
42	#elif RT_OS_WINDOWS
43	# include <Windows.h>
44	# include <stdio.h>
45
46	#else /* UNIXes */
47	# include <iprt/types.h> /* stdint fun on darwin. */
48
49	# include <stdio.h>
50	# include <stdlib.h>
51	# include <dlfcn.h>
52	# include <limits.h>
53	# include <errno.h>
54	# include <unistd.h>
55	# include <sys/stat.h>
56	# include <sys/time.h>
57	# include <stdio.h>
58	# include <sys/types.h>
59	# if defined(RT_OS_LINUX)
60	# undef USE_LIB_PCAP /* don't depend on libcap as we had to depend on either
61	libcap1 or libcap2 */
62
63	# undef _POSIX_SOURCE
64	# include <sys/capability.h>
65	# include <sys/prctl.h>
66	# ifndef CAP_TO_MASK
67	# define CAP_TO_MASK(cap) RT_BIT(cap)
68	# endif
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/param.h>
83
84	#include "SUPLibInternal.h"
85
86
87	/*******************************************************************************
88	* Defined Constants And Macros *
89	*******************************************************************************/
90	/** @def SUP_HARDENED_SUID
91	* Whether we're employing set-user-ID-on-execute in the hardening.
92	*/
93	#if !defined(RT_OS_OS2) && !defined(RT_OS_WINDOWS) && !defined(RT_OS_L4)
94	# define SUP_HARDENED_SUID
95	#else
96	# undef SUP_HARDENED_SUID
97	#endif
98
99	/** @def SUP_HARDENED_SYM
100	* Decorate a symbol that's resolved dynamically.
101	*/
102	#ifdef RT_OS_OS2
103	# define SUP_HARDENED_SYM(sym) "_" sym
104	#else
105	# define SUP_HARDENED_SYM(sym) sym
106	#endif
107
108
109	/*******************************************************************************
110	* Structures and Typedefs *
111	*******************************************************************************/
112	/** @see RTR3InitEx */
113	typedef DECLCALLBACK(int) FNRTR3INITEX(uint32_t iVersion, const char *pszProgramPath, bool fInitSUPLib);
114	typedef FNRTR3INITEX *PFNRTR3INITEX;
115
116
117	/*******************************************************************************
118	* Global Variables *
119	*******************************************************************************/
120	/** The pre-init data we pass on to SUPR3 (residing in VBoxRT). */
121	static SUPPREINITDATA g_SupPreInitData;
122	/** The progam executable path. */
123	static char g_szSupLibHardenedExePath[RTPATH_MAX];
124	/** The program directory path. */
125	static char g_szSupLibHardenedDirPath[RTPATH_MAX];
126
127	/** The program name. */
128	static const char *g_pszSupLibHardenedProgName;
129
130	#ifdef SUP_HARDENED_SUID
131	/** The real UID at startup. */
132	static uid_t g_uid;
133	/** The real GID at startup. */
134	static gid_t g_gid;
135	# ifdef RT_OS_LINUX
136	static uint32_t g_uCaps;
137	# endif
138	#endif
139
140	/*******************************************************************************
141	* Internal Functions *
142	*******************************************************************************/
143	#ifdef SUP_HARDENED_SUID
144	static void supR3HardenedMainDropPrivileges(void);
145	#endif
146	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName);
147
148
149	/**
150	* @copydoc RTPathStripFilename.
151	*/
152	static void suplibHardenedPathStripFilename(char *pszPath)
153	{
154	char *psz = pszPath;
155	char *pszLastSep = pszPath;
156
157	for (;; psz++)
158	{
159	switch (*psz)
160	{
161	/* handle separators. */
162	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
163	case ':':
164	pszLastSep = psz + 1;
165	break;
166
167	case '\\':
168	#endif
169	case '/':
170	pszLastSep = psz;
171	break;
172
173	/* the end */
174	case '\0':
175	if (pszLastSep == pszPath)
176	*pszLastSep++ = '.';
177	*pszLastSep = '\0';
178	return;
179	}
180	}
181	/* will never get here */
182	}
183
184
185	/**
186	* @copydoc RTPathFilename
187	*/
188	DECLHIDDEN(char ) supR3HardenedPathFilename(const char pszPath)
189	{
190	const char *psz = pszPath;
191	const char *pszLastComp = pszPath;
192
193	for (;; psz++)
194	{
195	switch (*psz)
196	{
197	/* handle separators. */
198	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
199	case ':':
200	pszLastComp = psz + 1;
201	break;
202
203	case '\\':
204	#endif
205	case '/':
206	pszLastComp = psz + 1;
207	break;
208
209	/* the end */
210	case '\0':
211	if (*pszLastComp)
212	return (char )(void )pszLastComp;
213	return NULL;
214	}
215	}
216
217	/* will never get here */
218	return NULL;
219	}
220
221
222	/**
223	* @copydoc RTPathAppPrivateNoArch
224	*/
225	DECLHIDDEN(int) supR3HardenedPathAppPrivateNoArch(char *pszPath, size_t cchPath)
226	{
227	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE)
228	const char *pszSrcPath = RTPATH_APP_PRIVATE;
229	size_t cchPathPrivateNoArch = strlen(pszSrcPath);
230	if (cchPathPrivateNoArch >= cchPath)
231	supR3HardenedFatal("supR3HardenedPathAppPrivateNoArch: Buffer overflow, %lu >= %lu\n",
232	(unsigned long)cchPathPrivateNoArch, (unsigned long)cchPath);
233	memcpy(pszPath, pszSrcPath, cchPathPrivateNoArch + 1);
234	return VINF_SUCCESS;
235
236	#else
237	return supR3HardenedPathProgram(pszPath, cchPath);
238	#endif
239	}
240
241
242	/**
243	* @copydoc RTPathAppPrivateArch
244	*/
245	DECLHIDDEN(int) supR3HardenedPathAppPrivateArch(char *pszPath, size_t cchPath)
246	{
247	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH)
248	const char *pszSrcPath = RTPATH_APP_PRIVATE_ARCH;
249	size_t cchPathPrivateArch = strlen(pszSrcPath);
250	if (cchPathPrivateArch >= cchPath)
251	supR3HardenedFatal("supR3HardenedPathAppPrivateArch: Buffer overflow, %lu >= %lu\n",
252	(unsigned long)cchPathPrivateArch, (unsigned long)cchPath);
253	memcpy(pszPath, pszSrcPath, cchPathPrivateArch + 1);
254	return VINF_SUCCESS;
255
256	#else
257	return supR3HardenedPathProgram(pszPath, cchPath);
258	#endif
259	}
260
261
262	/**
263	* @copydoc RTPathSharedLibs
264	*/
265	DECLHIDDEN(int) supR3HardenedPathSharedLibs(char *pszPath, size_t cchPath)
266	{
267	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_SHARED_LIBS)
268	const char *pszSrcPath = RTPATH_SHARED_LIBS;
269	size_t cchPathSharedLibs = strlen(pszSrcPath);
270	if (cchPathSharedLibs >= cchPath)
271	supR3HardenedFatal("supR3HardenedPathSharedLibs: Buffer overflow, %lu >= %lu\n",
272	(unsigned long)cchPathSharedLibs, (unsigned long)cchPath);
273	memcpy(pszPath, pszSrcPath, cchPathSharedLibs + 1);
274	return VINF_SUCCESS;
275
276	#else
277	return supR3HardenedPathProgram(pszPath, cchPath);
278	#endif
279	}
280
281
282	/**
283	* @copydoc RTPathAppDocs
284	*/
285	DECLHIDDEN(int) supR3HardenedPathAppDocs(char *pszPath, size_t cchPath)
286	{
287	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_DOCS)
288	const char *pszSrcPath = RTPATH_APP_DOCS;
289	size_t cchPathAppDocs = strlen(pszSrcPath);
290	if (cchPathAppDocs >= cchPath)
291	supR3HardenedFatal("supR3HardenedPathAppDocs: Buffer overflow, %lu >= %lu\n",
292	(unsigned long)cchPathAppDocs, (unsigned long)cchPath);
293	memcpy(pszPath, pszSrcPath, cchPathAppDocs + 1);
294	return VINF_SUCCESS;
295
296	#else
297	return supR3HardenedPathProgram(pszPath, cchPath);
298	#endif
299	}
300
301
302	/**
303	* Returns the full path to the executable.
304	*
305	* @returns IPRT status code.
306	* @param pszPath Where to store it.
307	* @param cchPath How big that buffer is.
308	*/
309	static void supR3HardenedGetFullExePath(void)
310	{
311	/*
312	* Get the program filename.
313	*
314	* Most UNIXes have no API for obtaining the executable path, but provides a symbolic
315	* link in the proc file system that tells who was exec'ed. The bad thing about this
316	* is that we have to use readlink, one of the weirder UNIX APIs.
317	*
318	* Darwin, OS/2 and Windows all have proper APIs for getting the program file name.
319	*/
320	#if defined(RT_OS_LINUX) \|\| defined(RT_OS_FREEBSD) \|\| defined(RT_OS_SOLARIS)
321	# ifdef RT_OS_LINUX
322	int cchLink = readlink("/proc/self/exe", &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
323	# elif defined(RT_OS_SOLARIS)
324	char szFileBuf[PATH_MAX + 1];
325	sprintf(szFileBuf, "/proc/%ld/path/a.out", (long)getpid());
326	int cchLink = readlink(szFileBuf, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
327	# else /* RT_OS_FREEBSD: */
328	int cchLink = readlink("/proc/curproc/file", &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
329	# endif
330	if (cchLink < 0 \|\| cchLink == sizeof(g_szSupLibHardenedExePath) - 1)
331	supR3HardenedFatal("supR3HardenedPathProgram: couldn't read \"%s\", errno=%d cchLink=%d\n",
332	g_szSupLibHardenedExePath, errno, cchLink);
333	g_szSupLibHardenedExePath[cchLink] = '\0';
334
335	#elif defined(RT_OS_OS2) \|\| defined(RT_OS_L4)
336	_execname(g_szSupLibHardenedExePath, sizeof(g_szSupLibHardenedExePath));
337
338	#elif defined(RT_OS_DARWIN)
339	const char *pszImageName = _dyld_get_image_name(0);
340	if (!pszImageName)
341	supR3HardenedFatal("supR3HardenedPathProgram: _dyld_get_image_name(0) failed\n");
342	size_t cchImageName = strlen(pszImageName);
343	if (!cchImageName \|\| cchImageName >= sizeof(g_szSupLibHardenedExePath))
344	supR3HardenedFatal("supR3HardenedPathProgram: _dyld_get_image_name(0) failed, cchImageName=%d\n", cchImageName);
345	memcpy(g_szSupLibHardenedExePath, pszImageName, cchImageName + 1);
346
347	#elif defined(RT_OS_WINDOWS)
348	HMODULE hExe = GetModuleHandle(NULL);
349	if (!GetModuleFileName(hExe, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath)))
350	supR3HardenedFatal("supR3HardenedPathProgram: GetModuleFileName failed, rc=%d\n", GetLastError());
351	#else
352	# error needs porting.
353	#endif
354
355	/*
356	* Strip off the filename part (RTPathStripFilename()).
357	*/
358	strcpy(g_szSupLibHardenedDirPath, g_szSupLibHardenedExePath);
359	suplibHardenedPathStripFilename(g_szSupLibHardenedDirPath);
360	}
361
362
363	#ifdef RT_OS_LINUX
364	/**
365	* Checks if we can read /proc/self/exe.
366	*
367	* This is used on linux to see if we have to call init
368	* with program path or not.
369	*
370	* @returns true / false.
371	*/
372	static bool supR3HardenedMainIsProcSelfExeAccssible(void)
373	{
374	char szPath[RTPATH_MAX];
375	int cchLink = readlink("/proc/self/exe", szPath, sizeof(szPath));
376	return cchLink != -1;
377	}
378	#endif /* RT_OS_LINUX */
379
380
381
382	/**
383	* @copydoc RTPathProgram
384	*/
385	DECLHIDDEN(int) supR3HardenedPathProgram(char *pszPath, size_t cchPath)
386	{
387	/*
388	* Lazy init (probably not required).
389	*/
390	if (!g_szSupLibHardenedDirPath[0])
391	supR3HardenedGetFullExePath();
392
393	/*
394	* Calc the length and check if there is space before copying.
395	*/
396	unsigned cch = strlen(g_szSupLibHardenedDirPath) + 1;
397	if (cch <= cchPath)
398	{
399	memcpy(pszPath, g_szSupLibHardenedDirPath, cch + 1);
400	return VINF_SUCCESS;
401	}
402
403	supR3HardenedFatal("supR3HardenedPathProgram: Buffer too small (%u < %u)\n", cchPath, cch);
404	return VERR_BUFFER_OVERFLOW;
405	}
406
407
408	DECLHIDDEN(void) supR3HardenedFatalMsgV(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, va_list va)
409	{
410	/*
411	* To the console first, like supR3HardenedFatalV.
412	*/
413	fprintf(stderr, "%s: Error %d in %s!\n", g_pszSupLibHardenedProgName, rc, pszWhere);
414	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
415	va_list vaCopy;
416	va_copy(vaCopy, va);
417	vfprintf(stderr, pszMsgFmt, vaCopy);
418	va_end(vaCopy);
419	fprintf(stderr, "\n");
420
421	switch (enmWhat)
422	{
423	case kSupInitOp_Driver:
424	fprintf(stderr,
425	"\n"
426	"%s: Tip! Make sure the kernel module is loaded. It may also help to reinstall VirtualBox.\n",
427	g_pszSupLibHardenedProgName);
428	break;
429
430	case kSupInitOp_IPRT:
431	case kSupInitOp_Integrity:
432	case kSupInitOp_RootCheck:
433	fprintf(stderr,
434	"\n"
435	"%s: Tip! It may help to reinstall VirtualBox.\n",
436	g_pszSupLibHardenedProgName);
437	break;
438
439	default:
440	/* no hints here */
441	break;
442	}
443
444	#ifdef SUP_HARDENED_SUID
445	/*
446	* Drop any root privileges we might be holding, this won't return
447	* if it fails but end up calling supR3HardenedFatal[V].
448	*/
449	supR3HardenedMainDropPrivileges();
450	#endif /* SUP_HARDENED_SUID */
451
452	/*
453	* Now try resolve and call the TrustedError entry point if we can
454	* find it. We'll fork before we attempt this because that way the
455	* session management in main will see us exiting immediately (if
456	* it's invovled with us).
457	*/
458	#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
459	int pid = fork();
460	if (pid <= 0)
461	#endif
462	{
463	PFNSUPTRUSTEDERROR pfnTrustedError = supR3HardenedMainGetTrustedError(g_pszSupLibHardenedProgName);
464	if (pfnTrustedError)
465	pfnTrustedError(pszWhere, enmWhat, rc, pszMsgFmt, va);
466	}
467
468	/*
469	* Quit
470	*/
471	for (;;)
472	#ifdef _MSC_VER
473	exit(1);
474	#else
475	_Exit(1);
476	#endif
477	}
478
479
480	DECLHIDDEN(void) supR3HardenedFatalMsg(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, ...)
481	{
482	va_list va;
483	va_start(va, pszMsgFmt);
484	supR3HardenedFatalMsgV(pszWhere, enmWhat, rc, pszMsgFmt, va);
485	va_end(va);
486	}
487
488
489	DECLHIDDEN(void) supR3HardenedFatalV(const char *pszFormat, va_list va)
490	{
491	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
492	vfprintf(stderr, pszFormat, va);
493	for (;;)
494	#ifdef _MSC_VER
495	exit(1);
496	#else
497	_Exit(1);
498	#endif
499	}
500
501
502	DECLHIDDEN(void) supR3HardenedFatal(const char *pszFormat, ...)
503	{
504	va_list va;
505	va_start(va, pszFormat);
506	supR3HardenedFatalV(pszFormat, va);
507	va_end(va);
508	}
509
510
511	DECLHIDDEN(int) supR3HardenedErrorV(int rc, bool fFatal, const char *pszFormat, va_list va)
512	{
513	if (fFatal)
514	supR3HardenedFatalV(pszFormat, va);
515
516	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
517	vfprintf(stderr, pszFormat, va);
518	return rc;
519	}
520
521
522	DECLHIDDEN(int) supR3HardenedError(int rc, bool fFatal, const char *pszFormat, ...)
523	{
524	va_list va;
525	va_start(va, pszFormat);
526	supR3HardenedErrorV(rc, fFatal, pszFormat, va);
527	va_end(va);
528	return rc;
529	}
530
531
532	/**
533	* Wrapper around snprintf which will throw a fatal error on buffer overflow.
534	*
535	* @returns Number of chars in the result string.
536	* @param pszDst The destination buffer.
537	* @param cchDst The size of the buffer.
538	* @param pszFormat The format string.
539	* @param ... Format arguments.
540	*/
541	static size_t supR3HardenedStrPrintf(char pszDst, size_t cchDst, const char pszFormat, ...)
542	{
543	va_list va;
544	va_start(va, pszFormat);
545	#ifdef _MSC_VER
546	int cch = _vsnprintf(pszDst, cchDst, pszFormat, va);
547	#else
548	int cch = vsnprintf(pszDst, cchDst, pszFormat, va);
549	#endif
550	va_end(va);
551	if ((unsigned)cch >= cchDst \|\| cch < 0)
552	supR3HardenedFatal("supR3HardenedStrPrintf: buffer overflow, %d >= %lu\n", cch, (long)cchDst);
553	return cch;
554	}
555
556
557	/**
558	* Attempts to open /dev/vboxdrv (or equvivalent).
559	*
560	* @remarks This function will not return on failure.
561	*/
562	static void supR3HardenedMainOpenDevice(void)
563	{
564	int rc = suplibOsInit(&g_SupPreInitData.Data, false);
565	if (RT_SUCCESS(rc))
566	return;
567
568	switch (rc)
569	{
570	/** @todo better messages! */
571	case VERR_VM_DRIVER_NOT_INSTALLED:
572	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
573	"VERR_VM_DRIVER_NOT_INSTALLED");
574	case VERR_VM_DRIVER_NOT_ACCESSIBLE:
575	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
576	"VERR_VM_DRIVER_NOT_ACCESSIBLE");
577	case VERR_VM_DRIVER_LOAD_ERROR:
578	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
579	"VERR_VM_DRIVER_LOAD_ERROR");
580	case VERR_VM_DRIVER_OPEN_ERROR:
581	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
582	"VERR_VM_DRIVER_OPEN_ERROR");
583	case VERR_VM_DRIVER_VERSION_MISMATCH:
584	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
585	"VERR_VM_DRIVER_VERSION_MISMATCH");
586	case VERR_ACCESS_DENIED:
587	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
588	"VERR_ACCESS_DENIED");
589	default:
590	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
591	"Unknown rc=%d", rc);
592	}
593	}
594
595
596	#ifdef SUP_HARDENED_SUID
597
598	/**
599	* Grabs extra non-root capabilities / privileges that we might require.
600	*
601	* This is currently only used for being able to do ICMP from the NAT engine.
602	*
603	* @note We still have root privileges at the time of this call.
604	*/
605	static void supR3HardenedMainGrabCapabilites(void)
606	{
607	# if defined(RT_OS_LINUX)
608	/*
609	* We are about to drop all our privileges. Remove all capabilities but
610	* keep the cap_net_raw capability for ICMP sockets for the NAT stack.
611	*/
612	if (g_uCaps != 0)
613	{
614	# ifdef USE_LIB_PCAP
615	/* XXX cap_net_bind_service */
616	if (!cap_set_proc(cap_from_text("all-eip cap_net_raw+ep")))
617	prctl(PR_SET_KEEPCAPS, /keep=/1, 0, 0, 0);
618	# else
619	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
620	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
621	memset(hdr, 0, sizeof(*hdr));
622	hdr->version = _LINUX_CAPABILITY_VERSION;
623	memset(cap, 0, sizeof(*cap));
624	cap->effective = g_uCaps;
625	cap->permitted = g_uCaps;
626	if (!capset(hdr, cap))
627	prctl(PR_SET_KEEPCAPS, /keep=/1, 0, 0, 0);
628	# endif /* !USE_LIB_PCAP */
629	}
630
631	# elif defined(RT_OS_SOLARIS)
632	/*
633	* Add net_icmpaccess privilege to permitted, effective and inheritable privileges
634	* before dropping root privileges.
635	*/
636	priv_set_t *pPrivSet = priv_str_to_set("basic", ",", NULL);
637	if (pPrivSet)
638	{
639	priv_addset(pPrivSet, PRIV_NET_ICMPACCESS);
640	int rc = setppriv(PRIV_SET, PRIV_INHERITABLE, pPrivSet);
641	if (!rc)
642	{
643	rc = setppriv(PRIV_SET, PRIV_PERMITTED, pPrivSet);
644	if (!rc)
645	{
646	rc = setppriv(PRIV_SET, PRIV_EFFECTIVE, pPrivSet);
647	if (rc)
648	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set effectives privilege set.\n");
649	}
650	else
651	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set permitted privilege set.\n");
652	}
653	else
654	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set inheritable privilege set.\n");
655
656	priv_freeset(pPrivSet);
657	}
658	else
659	supR3HardenedError(-1, false, "SUPR3HardenedMain: failed to get basic privilege set.\n");
660
661	# endif
662	}
663
664	/*
665	* Look at the environment for some special options.
666	*/
667	static void supR3GrabOptions(void)
668	{
669	const char *pszOpt;
670
671	# ifdef RT_OS_LINUX
672	g_uCaps = 0;
673
674	/*
675	* Do _not_ perform any capability-related system calls for root processes
676	* (leaving g_uCaps at 0).
677	* (Hint: getuid gets the real user id, not the effective.)
678	*/
679	if (getuid() != 0)
680	{
681	/*
682	* CAP_NET_RAW.
683	* Default: enabled.
684	* Can be disabled with 'export VBOX_HARD_CAP_NET_RAW=0'.
685	*/
686	pszOpt = getenv("VBOX_HARD_CAP_NET_RAW");
687	if ( !pszOpt
688	\|\| memcmp(pszOpt, "0", sizeof("0")) != 0)
689	g_uCaps = CAP_TO_MASK(CAP_NET_RAW);
690
691	/*
692	* CAP_NET_BIND_SERVICE.
693	* Default: disabled.
694	* Can be enabled with 'export VBOX_HARD_CAP_NET_BIND_SERVICE=1'.
695	*/
696	pszOpt = getenv("VBOX_HARD_CAP_NET_BIND_SERVICE");
697	if ( pszOpt
698	&& memcmp(pszOpt, "0", sizeof("0")) != 0)
699	g_uCaps \|= CAP_TO_MASK(CAP_NET_BIND_SERVICE);
700	}
701	# endif
702	}
703
704	/**
705	* Drop any root privileges we might be holding.
706	*/
707	static void supR3HardenedMainDropPrivileges(void)
708	{
709	/*
710	* Try use setre[ug]id since this will clear the save uid/gid and thus
711	* leave fewer traces behind that libs like GTK+ may pick up.
712	*/
713	uid_t euid, ruid, suid;
714	gid_t egid, rgid, sgid;
715	# if defined(RT_OS_DARWIN)
716	/* The really great thing here is that setreuid isn't available on
717	OS X 10.4, libc emulates it. While 10.4 have a sligtly different and
718	non-standard setuid implementation compared to 10.5, the following
719	works the same way with both version since we're super user (10.5 req).
720	The following will set all three variants of the group and user IDs. */
721	setgid(g_gid);
722	setuid(g_uid);
723	euid = geteuid();
724	ruid = suid = getuid();
725	egid = getegid();
726	rgid = sgid = getgid();
727
728	# elif defined(RT_OS_SOLARIS)
729	/* Solaris doesn't have setresuid, but the setreuid interface is BSD
730	compatible and will set the saved uid to euid when we pass it a ruid
731	that isn't -1 (which we do). */
732	setregid(g_gid, g_gid);
733	setreuid(g_uid, g_uid);
734	euid = geteuid();
735	ruid = suid = getuid();
736	egid = getegid();
737	rgid = sgid = getgid();
738
739	# else
740	/* This is the preferred one, full control no questions about semantics.
741	PORTME: If this isn't work, try join one of two other gangs above. */
742	setresgid(g_gid, g_gid, g_gid);
743	setresuid(g_uid, g_uid, g_uid);
744	if (getresuid(&ruid, &euid, &suid) != 0)
745	{
746	euid = geteuid();
747	ruid = suid = getuid();
748	}
749	if (getresgid(&rgid, &egid, &sgid) != 0)
750	{
751	egid = getegid();
752	rgid = sgid = getgid();
753	}
754	# endif
755
756
757	/* Check that it worked out all right. */
758	if ( euid != g_uid
759	\|\| ruid != g_uid
760	\|\| suid != g_uid
761	\|\| egid != g_gid
762	\|\| rgid != g_gid
763	\|\| sgid != g_gid)
764	supR3HardenedFatal("SUPR3HardenedMain: failed to drop root privileges!"
765	" (euid=%d ruid=%d suid=%d egid=%d rgid=%d sgid=%d; wanted uid=%d and gid=%d)\n",
766	euid, ruid, suid, egid, rgid, sgid, g_uid, g_gid);
767
768	# if RT_OS_LINUX
769	/*
770	* Re-enable the cap_net_raw capability which was disabled during setresuid.
771	*/
772	if (g_uCaps != 0)
773	{
774	# ifdef USE_LIB_PCAP
775	/** @todo Warn if that does not work? */
776	/* XXX cap_net_bind_service */
777	cap_set_proc(cap_from_text("cap_net_raw+ep"));
778	# else
779	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
780	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
781	memset(hdr, 0, sizeof(*hdr));
782	hdr->version = _LINUX_CAPABILITY_VERSION;
783	memset(cap, 0, sizeof(*cap));
784	cap->effective = g_uCaps;
785	cap->permitted = g_uCaps;
786	/** @todo Warn if that does not work? */
787	capset(hdr, cap);
788	# endif /* !USE_LIB_PCAP */
789	}
790	# endif
791	}
792
793	#endif /* SUP_HARDENED_SUID */
794
795	/**
796	* Loads the VBoxRT DLL/SO/DYLIB, hands it the open driver,
797	* and calls RTR3Init.
798	*
799	* @param fFlags The SUPR3HardenedMain fFlags argument, passed to supR3PreInit.
800	*
801	* @remarks VBoxRT contains both IPRT and SUPR3.
802	* @remarks This function will not return on failure.
803	*/
804	static void supR3HardenedMainInitRuntime(uint32_t fFlags)
805	{
806	/*
807	* Construct the name.
808	*/
809	char szPath[RTPATH_MAX];
810	supR3HardenedPathSharedLibs(szPath, sizeof(szPath) - sizeof("/VBoxRT" SUPLIB_DLL_SUFF));
811	strcat(szPath, "/VBoxRT" SUPLIB_DLL_SUFF);
812
813	/*
814	* Open it and resolve the symbols.
815	*/
816	#if defined(RT_OS_WINDOWS)
817	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
818	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
819	if (!hMod)
820	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
821	"LoadLibraryEx(\"%s\",,) failed (rc=%d)",
822	szPath, GetLastError());
823	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)GetProcAddress(hMod, SUP_HARDENED_SYM("RTR3InitEx"));
824	if (!pfnRTInitEx)
825	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
826	"Entrypoint \"RTR3InitEx\" not found in \"%s\" (rc=%d)",
827	szPath, GetLastError());
828
829	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)GetProcAddress(hMod, SUP_HARDENED_SYM("supR3PreInit"));
830	if (!pfnSUPPreInit)
831	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
832	"Entrypoint \"supR3PreInit\" not found in \"%s\" (rc=%d)",
833	szPath, GetLastError());
834
835	#else
836	/* the dlopen crowd */
837	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
838	if (!pvMod)
839	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
840	"dlopen(\"%s\",) failed: %s",
841	szPath, dlerror());
842	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("RTR3InitEx"));
843	if (!pfnRTInitEx)
844	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
845	"Entrypoint \"RTR3InitEx\" not found in \"%s\"!\ndlerror: %s",
846	szPath, dlerror());
847	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("supR3PreInit"));
848	if (!pfnSUPPreInit)
849	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
850	"Entrypoint \"supR3PreInit\" not found in \"%s\"!\ndlerror: %s",
851	szPath, dlerror());
852	#endif
853
854	/*
855	* Make the calls.
856	*/
857	supR3HardenedGetPreInitData(&g_SupPreInitData);
858	int rc = pfnSUPPreInit(&g_SupPreInitData, fFlags);
859	if (RT_FAILURE(rc))
860	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
861	"supR3PreInit failed with rc=%d", rc);
862	const char *pszExePath = NULL;
863	#ifdef RT_OS_LINUX
864	if (!supR3HardenedMainIsProcSelfExeAccssible())
865	pszExePath = g_szSupLibHardenedExePath;
866	#endif
867	rc = pfnRTInitEx(0, pszExePath, !(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV));
868	if (RT_FAILURE(rc))
869	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
870	"RTR3Init failed with rc=%d", rc);
871	}
872
873
874	/**
875	* Loads the DLL/SO/DYLIB containing the actual program and
876	* resolves the TrustedError symbol.
877	*
878	* This is very similar to supR3HardenedMainGetTrustedMain().
879	*
880	* @returns Pointer to the trusted error symbol if it is exported, NULL
881	* and no error messages otherwise.
882	* @param pszProgName The program name.
883	*/
884	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName)
885	{
886	/*
887	* Construct the name.
888	*/
889	char szPath[RTPATH_MAX];
890	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
891	size_t cch = strlen(szPath);
892	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
893
894	/*
895	* Open it and resolve the symbol.
896	*/
897	#if defined(RT_OS_WINDOWS)
898	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
899	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
900	if (!hMod)
901	return NULL;
902	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedError"));
903	if (!pfn)
904	return NULL;
905	return (PFNSUPTRUSTEDERROR)pfn;
906
907	#else
908	/* the dlopen crowd */
909	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
910	if (!pvMod)
911	return NULL;
912	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedError"));
913	if (!pvSym)
914	return NULL;
915	return (PFNSUPTRUSTEDERROR)(uintptr_t)pvSym;
916	#endif
917	}
918
919
920	/**
921	* Loads the DLL/SO/DYLIB containing the actual program and
922	* resolves the TrustedMain symbol.
923	*
924	* @returns Pointer to the trusted main of the actual program.
925	* @param pszProgName The program name.
926	* @remarks This function will not return on failure.
927	*/
928	static PFNSUPTRUSTEDMAIN supR3HardenedMainGetTrustedMain(const char *pszProgName)
929	{
930	/*
931	* Construct the name.
932	*/
933	char szPath[RTPATH_MAX];
934	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
935	size_t cch = strlen(szPath);
936	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
937
938	/*
939	* Open it and resolve the symbol.
940	*/
941	#if defined(RT_OS_WINDOWS)
942	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
943	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
944	if (!hMod)
945	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: LoadLibraryEx(\"%s\",,) failed, rc=%d\n",
946	szPath, GetLastError());
947	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedMain"));
948	if (!pfn)
949	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\" (rc=%d)\n",
950	szPath, GetLastError());
951	return (PFNSUPTRUSTEDMAIN)pfn;
952
953	#else
954	/* the dlopen crowd */
955	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
956	if (!pvMod)
957	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: dlopen(\"%s\",) failed: %s\n",
958	szPath, dlerror());
959	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedMain"));
960	if (!pvSym)
961	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\"!\ndlerror: %s\n",
962	szPath, dlerror());
963	return (PFNSUPTRUSTEDMAIN)(uintptr_t)pvSym;
964	#endif
965	}
966
967
968	/**
969	* Secure main.
970	*
971	* This is used for the set-user-ID-on-execute binaries on unixy systems
972	* and when using the open-vboxdrv-via-root-service setup on Windows.
973	*
974	* This function will perform the integrity checks of the VirtualBox
975	* installation, open the support driver, open the root service (later),
976	* and load the DLL corresponding to \a pszProgName and execute its main
977	* function.
978	*
979	* @returns Return code appropriate for main().
980	*
981	* @param pszProgName The program name. This will be used to figure out which
982	* DLL/SO/DYLIB to load and execute.
983	* @param fFlags Flags.
984	* @param argc The argument count.
985	* @param argv The argument vector.
986	* @param envp The environment vector.
987	*/
988	DECLHIDDEN(int) SUPR3HardenedMain(const char pszProgName, uint32_t fFlags, int argc, char argv, char *envp)
989	{
990	/*
991	* Note! At this point there is no IPRT, so we will have to stick
992	* to basic CRT functions that everyone agree upon.
993	*/
994	g_pszSupLibHardenedProgName = pszProgName;
995	g_SupPreInitData.u32Magic = SUPPREINITDATA_MAGIC;
996	g_SupPreInitData.Data.hDevice = NIL_RTFILE;
997	g_SupPreInitData.u32EndMagic = SUPPREINITDATA_MAGIC;
998
999	#ifdef SUP_HARDENED_SUID
1000	# ifdef RT_OS_LINUX
1001	/*
1002	* On linux we have to make sure the path is initialized because we
1003	* might not be able to access /proc/self/exe after the seteuid call.
1004	*/
1005	supR3HardenedGetFullExePath();
1006
1007	# endif
1008
1009	/*
1010	* Grab any options from the environment.
1011	*/
1012	supR3GrabOptions();
1013
1014	/*
1015	* Check that we're root, if we aren't then the installation is butchered.
1016	*/
1017	g_uid = getuid();
1018	g_gid = getgid();
1019	if (geteuid() != 0 /* root */)
1020	supR3HardenedFatalMsg("SUPR3HardenedMain", kSupInitOp_RootCheck, VERR_PERMISSION_DENIED,
1021	"Effective UID is not root (euid=%d egid=%d uid=%d gid=%d)",
1022	geteuid(), getegid(), g_uid, g_gid);
1023	#endif
1024
1025	/*
1026	* Validate the installation.
1027	*/
1028	supR3HardenedVerifyAll(true /* fFatal /, false / fLeaveFilesOpen */, pszProgName);
1029
1030	/*
1031	* Open the vboxdrv device.
1032	*/
1033	if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV))
1034	supR3HardenedMainOpenDevice();
1035
1036	/*
1037	* Open the root service connection.
1038	*/
1039	//if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_SVC))
1040	//supR3HardenedMainOpenService(&g_SupPreInitData, true /* fFatal */);
1041
1042	#ifdef SUP_HARDENED_SUID
1043	/*
1044	* Grab additional capabilities / privileges.
1045	*/
1046	supR3HardenedMainGrabCapabilites();
1047
1048	/*
1049	* Drop any root privileges we might be holding (won't return on failure)
1050	*/
1051	supR3HardenedMainDropPrivileges();
1052	#endif
1053
1054	/*
1055	* Load the IPRT, hand the SUPLib part the open driver and
1056	* call RTR3Init.
1057	*/
1058	supR3HardenedMainInitRuntime(fFlags);
1059
1060	/*
1061	* Load the DLL/SO/DYLIB containing the actual program
1062	* and pass control to it.
1063	*/
1064	PFNSUPTRUSTEDMAIN pfnTrustedMain = supR3HardenedMainGetTrustedMain(pszProgName);
1065	return pfnTrustedMain(argc, argv, envp);
1066	}
1067
1068

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source: vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp@ 17827

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