SUPR3HardenedMain.cpp@ 18265

Last change on this file since 18265 was 18242, checked in by vboxsync, 16 years ago
FE/Qt4: better error messages if something goes wrong during the Runtime initialization
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 34.0 KB

Line
1	/* $Id: SUPR3HardenedMain.cpp 18242 2009-03-25 10:00:57Z 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	"Kernel driver not installed");
574	case VERR_VM_DRIVER_NOT_ACCESSIBLE:
575	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
576	"Kernel 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	"Kernel driver version mismatch");
586	case VERR_ACCESS_DENIED:
587	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
588	"VERR_ACCESS_DENIED");
589	case VERR_NO_MEMORY:
590	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
591	"Kernel memory allocation/mapping failed");
592	default:
593	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
594	"Unknown rc=%d", rc);
595	}
596	}
597
598
599	#ifdef SUP_HARDENED_SUID
600
601	/**
602	* Grabs extra non-root capabilities / privileges that we might require.
603	*
604	* This is currently only used for being able to do ICMP from the NAT engine.
605	*
606	* @note We still have root privileges at the time of this call.
607	*/
608	static void supR3HardenedMainGrabCapabilites(void)
609	{
610	# if defined(RT_OS_LINUX)
611	/*
612	* We are about to drop all our privileges. Remove all capabilities but
613	* keep the cap_net_raw capability for ICMP sockets for the NAT stack.
614	*/
615	if (g_uCaps != 0)
616	{
617	# ifdef USE_LIB_PCAP
618	/* XXX cap_net_bind_service */
619	if (!cap_set_proc(cap_from_text("all-eip cap_net_raw+ep")))
620	prctl(PR_SET_KEEPCAPS, /keep=/1, 0, 0, 0);
621	# else
622	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
623	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
624	memset(hdr, 0, sizeof(*hdr));
625	hdr->version = _LINUX_CAPABILITY_VERSION;
626	memset(cap, 0, sizeof(*cap));
627	cap->effective = g_uCaps;
628	cap->permitted = g_uCaps;
629	if (!capset(hdr, cap))
630	prctl(PR_SET_KEEPCAPS, /keep=/1, 0, 0, 0);
631	# endif /* !USE_LIB_PCAP */
632	}
633
634	# elif defined(RT_OS_SOLARIS)
635	/*
636	* Add net_icmpaccess privilege to permitted, effective and inheritable privileges
637	* before dropping root privileges.
638	*/
639	priv_set_t *pPrivSet = priv_str_to_set("basic", ",", NULL);
640	if (pPrivSet)
641	{
642	priv_addset(pPrivSet, PRIV_NET_ICMPACCESS);
643	int rc = setppriv(PRIV_SET, PRIV_INHERITABLE, pPrivSet);
644	if (!rc)
645	{
646	rc = setppriv(PRIV_SET, PRIV_PERMITTED, pPrivSet);
647	if (!rc)
648	{
649	rc = setppriv(PRIV_SET, PRIV_EFFECTIVE, pPrivSet);
650	if (rc)
651	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set effectives privilege set.\n");
652	}
653	else
654	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set permitted privilege set.\n");
655	}
656	else
657	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set inheritable privilege set.\n");
658
659	priv_freeset(pPrivSet);
660	}
661	else
662	supR3HardenedError(-1, false, "SUPR3HardenedMain: failed to get basic privilege set.\n");
663
664	# endif
665	}
666
667	/*
668	* Look at the environment for some special options.
669	*/
670	static void supR3GrabOptions(void)
671	{
672	const char *pszOpt;
673
674	# ifdef RT_OS_LINUX
675	g_uCaps = 0;
676
677	/*
678	* Do _not_ perform any capability-related system calls for root processes
679	* (leaving g_uCaps at 0).
680	* (Hint: getuid gets the real user id, not the effective.)
681	*/
682	if (getuid() != 0)
683	{
684	/*
685	* CAP_NET_RAW.
686	* Default: enabled.
687	* Can be disabled with 'export VBOX_HARD_CAP_NET_RAW=0'.
688	*/
689	pszOpt = getenv("VBOX_HARD_CAP_NET_RAW");
690	if ( !pszOpt
691	\|\| memcmp(pszOpt, "0", sizeof("0")) != 0)
692	g_uCaps = CAP_TO_MASK(CAP_NET_RAW);
693
694	/*
695	* CAP_NET_BIND_SERVICE.
696	* Default: disabled.
697	* Can be enabled with 'export VBOX_HARD_CAP_NET_BIND_SERVICE=1'.
698	*/
699	pszOpt = getenv("VBOX_HARD_CAP_NET_BIND_SERVICE");
700	if ( pszOpt
701	&& memcmp(pszOpt, "0", sizeof("0")) != 0)
702	g_uCaps \|= CAP_TO_MASK(CAP_NET_BIND_SERVICE);
703	}
704	# endif
705	}
706
707	/**
708	* Drop any root privileges we might be holding.
709	*/
710	static void supR3HardenedMainDropPrivileges(void)
711	{
712	/*
713	* Try use setre[ug]id since this will clear the save uid/gid and thus
714	* leave fewer traces behind that libs like GTK+ may pick up.
715	*/
716	uid_t euid, ruid, suid;
717	gid_t egid, rgid, sgid;
718	# if defined(RT_OS_DARWIN)
719	/* The really great thing here is that setreuid isn't available on
720	OS X 10.4, libc emulates it. While 10.4 have a sligtly different and
721	non-standard setuid implementation compared to 10.5, the following
722	works the same way with both version since we're super user (10.5 req).
723	The following will set all three variants of the group and user IDs. */
724	setgid(g_gid);
725	setuid(g_uid);
726	euid = geteuid();
727	ruid = suid = getuid();
728	egid = getegid();
729	rgid = sgid = getgid();
730
731	# elif defined(RT_OS_SOLARIS)
732	/* Solaris doesn't have setresuid, but the setreuid interface is BSD
733	compatible and will set the saved uid to euid when we pass it a ruid
734	that isn't -1 (which we do). */
735	setregid(g_gid, g_gid);
736	setreuid(g_uid, g_uid);
737	euid = geteuid();
738	ruid = suid = getuid();
739	egid = getegid();
740	rgid = sgid = getgid();
741
742	# else
743	/* This is the preferred one, full control no questions about semantics.
744	PORTME: If this isn't work, try join one of two other gangs above. */
745	setresgid(g_gid, g_gid, g_gid);
746	setresuid(g_uid, g_uid, g_uid);
747	if (getresuid(&ruid, &euid, &suid) != 0)
748	{
749	euid = geteuid();
750	ruid = suid = getuid();
751	}
752	if (getresgid(&rgid, &egid, &sgid) != 0)
753	{
754	egid = getegid();
755	rgid = sgid = getgid();
756	}
757	# endif
758
759
760	/* Check that it worked out all right. */
761	if ( euid != g_uid
762	\|\| ruid != g_uid
763	\|\| suid != g_uid
764	\|\| egid != g_gid
765	\|\| rgid != g_gid
766	\|\| sgid != g_gid)
767	supR3HardenedFatal("SUPR3HardenedMain: failed to drop root privileges!"
768	" (euid=%d ruid=%d suid=%d egid=%d rgid=%d sgid=%d; wanted uid=%d and gid=%d)\n",
769	euid, ruid, suid, egid, rgid, sgid, g_uid, g_gid);
770
771	# if RT_OS_LINUX
772	/*
773	* Re-enable the cap_net_raw capability which was disabled during setresuid.
774	*/
775	if (g_uCaps != 0)
776	{
777	# ifdef USE_LIB_PCAP
778	/** @todo Warn if that does not work? */
779	/* XXX cap_net_bind_service */
780	cap_set_proc(cap_from_text("cap_net_raw+ep"));
781	# else
782	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
783	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
784	memset(hdr, 0, sizeof(*hdr));
785	hdr->version = _LINUX_CAPABILITY_VERSION;
786	memset(cap, 0, sizeof(*cap));
787	cap->effective = g_uCaps;
788	cap->permitted = g_uCaps;
789	/** @todo Warn if that does not work? */
790	capset(hdr, cap);
791	# endif /* !USE_LIB_PCAP */
792	}
793	# endif
794	}
795
796	#endif /* SUP_HARDENED_SUID */
797
798	/**
799	* Loads the VBoxRT DLL/SO/DYLIB, hands it the open driver,
800	* and calls RTR3Init.
801	*
802	* @param fFlags The SUPR3HardenedMain fFlags argument, passed to supR3PreInit.
803	*
804	* @remarks VBoxRT contains both IPRT and SUPR3.
805	* @remarks This function will not return on failure.
806	*/
807	static void supR3HardenedMainInitRuntime(uint32_t fFlags)
808	{
809	/*
810	* Construct the name.
811	*/
812	char szPath[RTPATH_MAX];
813	supR3HardenedPathSharedLibs(szPath, sizeof(szPath) - sizeof("/VBoxRT" SUPLIB_DLL_SUFF));
814	strcat(szPath, "/VBoxRT" SUPLIB_DLL_SUFF);
815
816	/*
817	* Open it and resolve the symbols.
818	*/
819	#if defined(RT_OS_WINDOWS)
820	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
821	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
822	if (!hMod)
823	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
824	"LoadLibraryEx(\"%s\",,) failed (rc=%d)",
825	szPath, GetLastError());
826	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)GetProcAddress(hMod, SUP_HARDENED_SYM("RTR3InitEx"));
827	if (!pfnRTInitEx)
828	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
829	"Entrypoint \"RTR3InitEx\" not found in \"%s\" (rc=%d)",
830	szPath, GetLastError());
831
832	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)GetProcAddress(hMod, SUP_HARDENED_SYM("supR3PreInit"));
833	if (!pfnSUPPreInit)
834	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
835	"Entrypoint \"supR3PreInit\" not found in \"%s\" (rc=%d)",
836	szPath, GetLastError());
837
838	#else
839	/* the dlopen crowd */
840	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
841	if (!pvMod)
842	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
843	"dlopen(\"%s\",) failed: %s",
844	szPath, dlerror());
845	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("RTR3InitEx"));
846	if (!pfnRTInitEx)
847	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
848	"Entrypoint \"RTR3InitEx\" not found in \"%s\"!\ndlerror: %s",
849	szPath, dlerror());
850	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("supR3PreInit"));
851	if (!pfnSUPPreInit)
852	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
853	"Entrypoint \"supR3PreInit\" not found in \"%s\"!\ndlerror: %s",
854	szPath, dlerror());
855	#endif
856
857	/*
858	* Make the calls.
859	*/
860	supR3HardenedGetPreInitData(&g_SupPreInitData);
861	int rc = pfnSUPPreInit(&g_SupPreInitData, fFlags);
862	if (RT_FAILURE(rc))
863	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
864	"supR3PreInit failed with rc=%d", rc);
865	const char *pszExePath = NULL;
866	#ifdef RT_OS_LINUX
867	if (!supR3HardenedMainIsProcSelfExeAccssible())
868	pszExePath = g_szSupLibHardenedExePath;
869	#endif
870	rc = pfnRTInitEx(0, pszExePath, !(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV));
871	if (RT_FAILURE(rc))
872	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
873	"RTR3Init failed with rc=%d", rc);
874	}
875
876
877	/**
878	* Loads the DLL/SO/DYLIB containing the actual program and
879	* resolves the TrustedError symbol.
880	*
881	* This is very similar to supR3HardenedMainGetTrustedMain().
882	*
883	* @returns Pointer to the trusted error symbol if it is exported, NULL
884	* and no error messages otherwise.
885	* @param pszProgName The program name.
886	*/
887	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName)
888	{
889	/*
890	* Construct the name.
891	*/
892	char szPath[RTPATH_MAX];
893	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
894	size_t cch = strlen(szPath);
895	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
896
897	/*
898	* Open it and resolve the symbol.
899	*/
900	#if defined(RT_OS_WINDOWS)
901	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
902	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
903	if (!hMod)
904	return NULL;
905	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedError"));
906	if (!pfn)
907	return NULL;
908	return (PFNSUPTRUSTEDERROR)pfn;
909
910	#else
911	/* the dlopen crowd */
912	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
913	if (!pvMod)
914	return NULL;
915	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedError"));
916	if (!pvSym)
917	return NULL;
918	return (PFNSUPTRUSTEDERROR)(uintptr_t)pvSym;
919	#endif
920	}
921
922
923	/**
924	* Loads the DLL/SO/DYLIB containing the actual program and
925	* resolves the TrustedMain symbol.
926	*
927	* @returns Pointer to the trusted main of the actual program.
928	* @param pszProgName The program name.
929	* @remarks This function will not return on failure.
930	*/
931	static PFNSUPTRUSTEDMAIN supR3HardenedMainGetTrustedMain(const char *pszProgName)
932	{
933	/*
934	* Construct the name.
935	*/
936	char szPath[RTPATH_MAX];
937	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
938	size_t cch = strlen(szPath);
939	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
940
941	/*
942	* Open it and resolve the symbol.
943	*/
944	#if defined(RT_OS_WINDOWS)
945	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
946	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
947	if (!hMod)
948	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: LoadLibraryEx(\"%s\",,) failed, rc=%d\n",
949	szPath, GetLastError());
950	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedMain"));
951	if (!pfn)
952	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\" (rc=%d)\n",
953	szPath, GetLastError());
954	return (PFNSUPTRUSTEDMAIN)pfn;
955
956	#else
957	/* the dlopen crowd */
958	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
959	if (!pvMod)
960	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: dlopen(\"%s\",) failed: %s\n",
961	szPath, dlerror());
962	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedMain"));
963	if (!pvSym)
964	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\"!\ndlerror: %s\n",
965	szPath, dlerror());
966	return (PFNSUPTRUSTEDMAIN)(uintptr_t)pvSym;
967	#endif
968	}
969
970
971	/**
972	* Secure main.
973	*
974	* This is used for the set-user-ID-on-execute binaries on unixy systems
975	* and when using the open-vboxdrv-via-root-service setup on Windows.
976	*
977	* This function will perform the integrity checks of the VirtualBox
978	* installation, open the support driver, open the root service (later),
979	* and load the DLL corresponding to \a pszProgName and execute its main
980	* function.
981	*
982	* @returns Return code appropriate for main().
983	*
984	* @param pszProgName The program name. This will be used to figure out which
985	* DLL/SO/DYLIB to load and execute.
986	* @param fFlags Flags.
987	* @param argc The argument count.
988	* @param argv The argument vector.
989	* @param envp The environment vector.
990	*/
991	DECLHIDDEN(int) SUPR3HardenedMain(const char pszProgName, uint32_t fFlags, int argc, char argv, char *envp)
992	{
993	/*
994	* Note! At this point there is no IPRT, so we will have to stick
995	* to basic CRT functions that everyone agree upon.
996	*/
997	g_pszSupLibHardenedProgName = pszProgName;
998	g_SupPreInitData.u32Magic = SUPPREINITDATA_MAGIC;
999	g_SupPreInitData.Data.hDevice = NIL_RTFILE;
1000	g_SupPreInitData.u32EndMagic = SUPPREINITDATA_MAGIC;
1001
1002	#ifdef SUP_HARDENED_SUID
1003	# ifdef RT_OS_LINUX
1004	/*
1005	* On linux we have to make sure the path is initialized because we
1006	* might not be able to access /proc/self/exe after the seteuid call.
1007	*/
1008	supR3HardenedGetFullExePath();
1009
1010	# endif
1011
1012	/*
1013	* Grab any options from the environment.
1014	*/
1015	supR3GrabOptions();
1016
1017	/*
1018	* Check that we're root, if we aren't then the installation is butchered.
1019	*/
1020	g_uid = getuid();
1021	g_gid = getgid();
1022	if (geteuid() != 0 /* root */)
1023	supR3HardenedFatalMsg("SUPR3HardenedMain", kSupInitOp_RootCheck, VERR_PERMISSION_DENIED,
1024	"Effective UID is not root (euid=%d egid=%d uid=%d gid=%d)",
1025	geteuid(), getegid(), g_uid, g_gid);
1026	#endif
1027
1028	/*
1029	* Validate the installation.
1030	*/
1031	supR3HardenedVerifyAll(true /* fFatal /, false / fLeaveFilesOpen */, pszProgName);
1032
1033	/*
1034	* Open the vboxdrv device.
1035	*/
1036	if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV))
1037	supR3HardenedMainOpenDevice();
1038
1039	/*
1040	* Open the root service connection.
1041	*/
1042	//if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_SVC))
1043	//supR3HardenedMainOpenService(&g_SupPreInitData, true /* fFatal */);
1044
1045	#ifdef SUP_HARDENED_SUID
1046	/*
1047	* Grab additional capabilities / privileges.
1048	*/
1049	supR3HardenedMainGrabCapabilites();
1050
1051	/*
1052	* Drop any root privileges we might be holding (won't return on failure)
1053	*/
1054	supR3HardenedMainDropPrivileges();
1055	#endif
1056
1057	/*
1058	* Load the IPRT, hand the SUPLib part the open driver and
1059	* call RTR3Init.
1060	*/
1061	supR3HardenedMainInitRuntime(fFlags);
1062
1063	/*
1064	* Load the DLL/SO/DYLIB containing the actual program
1065	* and pass control to it.
1066	*/
1067	PFNSUPTRUSTEDMAIN pfnTrustedMain = supR3HardenedMainGetTrustedMain(pszProgName);
1068	return pfnTrustedMain(argc, argv, envp);
1069	}
1070
1071

Note: See TracBrowser for help on using the repository browser.

source: vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp@ 18265

Download in other formats: