SUPR3HardenedMain.cpp@ 38895

Last change on this file since 38895 was 38636, checked in by vboxsync, 13 years ago
*,IPRT: Redid the ring-3 init to always convert the arguments to UTF-8.
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1	/* $Id: SUPR3HardenedMain.cpp 38636 2011-09-05 13:49:45Z vboxsync $ */
2	/** @file
3	* VirtualBox Support Library - Hardened main().
4	*/
5
6	/*
7	* Copyright (C) 2006-2010 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 <sys/capability.h>
61	# include <sys/prctl.h>
62	# ifndef CAP_TO_MASK
63	# define CAP_TO_MASK(cap) RT_BIT(cap)
64	# endif
65	# elif defined(RT_OS_FREEBSD)
66	# include <sys/param.h>
67	# include <sys/sysctl.h>
68	# elif defined(RT_OS_SOLARIS)
69	# include <priv.h>
70	# endif
71	# include <pwd.h>
72	# ifdef RT_OS_DARWIN
73	# include <mach-o/dyld.h>
74	# endif
75
76	#endif
77
78	#include <VBox/sup.h>
79	#include <VBox/err.h>
80	#include <iprt/string.h>
81	#include <iprt/initterm.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, uint32_t fFlags, int cArgs,
114	char *papszArgs, const char pszProgramPath);
115	typedef FNRTR3INITEX *PFNRTR3INITEX;
116
117
118	/*******************************************************************************
119	* Global Variables *
120	*******************************************************************************/
121	/** The pre-init data we pass on to SUPR3 (residing in VBoxRT). */
122	static SUPPREINITDATA g_SupPreInitData;
123	/** The program executable path. */
124	static char g_szSupLibHardenedExePath[RTPATH_MAX];
125	/** The program directory path. */
126	static char g_szSupLibHardenedDirPath[RTPATH_MAX];
127
128	/** The program name. */
129	static const char *g_pszSupLibHardenedProgName;
130
131	#ifdef SUP_HARDENED_SUID
132	/** The real UID at startup. */
133	static uid_t g_uid;
134	/** The real GID at startup. */
135	static gid_t g_gid;
136	# ifdef RT_OS_LINUX
137	static uint32_t g_uCaps;
138	# endif
139	#endif
140
141
142	/*******************************************************************************
143	* Internal Functions *
144	*******************************************************************************/
145	#ifdef SUP_HARDENED_SUID
146	static void supR3HardenedMainDropPrivileges(void);
147	#endif
148	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName);
149
150
151	/**
152	* @copydoc RTPathStripFilename.
153	*/
154	static void suplibHardenedPathStripFilename(char *pszPath)
155	{
156	char *psz = pszPath;
157	char *pszLastSep = pszPath;
158
159	for (;; psz++)
160	{
161	switch (*psz)
162	{
163	/* handle separators. */
164	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
165	case ':':
166	pszLastSep = psz + 1;
167	break;
168
169	case '\\':
170	#endif
171	case '/':
172	pszLastSep = psz;
173	break;
174
175	/* the end */
176	case '\0':
177	if (pszLastSep == pszPath)
178	*pszLastSep++ = '.';
179	*pszLastSep = '\0';
180	return;
181	}
182	}
183	/* will never get here */
184	}
185
186
187	/**
188	* @copydoc RTPathFilename
189	*/
190	DECLHIDDEN(char ) supR3HardenedPathFilename(const char pszPath)
191	{
192	const char *psz = pszPath;
193	const char *pszLastComp = pszPath;
194
195	for (;; psz++)
196	{
197	switch (*psz)
198	{
199	/* handle separators. */
200	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
201	case ':':
202	pszLastComp = psz + 1;
203	break;
204
205	case '\\':
206	#endif
207	case '/':
208	pszLastComp = psz + 1;
209	break;
210
211	/* the end */
212	case '\0':
213	if (*pszLastComp)
214	return (char )(void )pszLastComp;
215	return NULL;
216	}
217	}
218
219	/* will never get here */
220	return NULL;
221	}
222
223
224	/**
225	* @copydoc RTPathAppPrivateNoArch
226	*/
227	DECLHIDDEN(int) supR3HardenedPathAppPrivateNoArch(char *pszPath, size_t cchPath)
228	{
229	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE)
230	const char *pszSrcPath = RTPATH_APP_PRIVATE;
231	size_t cchPathPrivateNoArch = strlen(pszSrcPath);
232	if (cchPathPrivateNoArch >= cchPath)
233	supR3HardenedFatal("supR3HardenedPathAppPrivateNoArch: Buffer overflow, %lu >= %lu\n",
234	(unsigned long)cchPathPrivateNoArch, (unsigned long)cchPath);
235	memcpy(pszPath, pszSrcPath, cchPathPrivateNoArch + 1);
236	return VINF_SUCCESS;
237
238	#else
239	return supR3HardenedPathExecDir(pszPath, cchPath);
240	#endif
241	}
242
243
244	/**
245	* @copydoc RTPathAppPrivateArch
246	*/
247	DECLHIDDEN(int) supR3HardenedPathAppPrivateArch(char *pszPath, size_t cchPath)
248	{
249	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH)
250	const char *pszSrcPath = RTPATH_APP_PRIVATE_ARCH;
251	size_t cchPathPrivateArch = strlen(pszSrcPath);
252	if (cchPathPrivateArch >= cchPath)
253	supR3HardenedFatal("supR3HardenedPathAppPrivateArch: Buffer overflow, %lu >= %lu\n",
254	(unsigned long)cchPathPrivateArch, (unsigned long)cchPath);
255	memcpy(pszPath, pszSrcPath, cchPathPrivateArch + 1);
256	return VINF_SUCCESS;
257
258	#else
259	return supR3HardenedPathExecDir(pszPath, cchPath);
260	#endif
261	}
262
263
264	/**
265	* @copydoc RTPathSharedLibs
266	*/
267	DECLHIDDEN(int) supR3HardenedPathSharedLibs(char *pszPath, size_t cchPath)
268	{
269	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_SHARED_LIBS)
270	const char *pszSrcPath = RTPATH_SHARED_LIBS;
271	size_t cchPathSharedLibs = strlen(pszSrcPath);
272	if (cchPathSharedLibs >= cchPath)
273	supR3HardenedFatal("supR3HardenedPathSharedLibs: Buffer overflow, %lu >= %lu\n",
274	(unsigned long)cchPathSharedLibs, (unsigned long)cchPath);
275	memcpy(pszPath, pszSrcPath, cchPathSharedLibs + 1);
276	return VINF_SUCCESS;
277
278	#else
279	return supR3HardenedPathExecDir(pszPath, cchPath);
280	#endif
281	}
282
283
284	/**
285	* @copydoc RTPathAppDocs
286	*/
287	DECLHIDDEN(int) supR3HardenedPathAppDocs(char *pszPath, size_t cchPath)
288	{
289	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_DOCS)
290	const char *pszSrcPath = RTPATH_APP_DOCS;
291	size_t cchPathAppDocs = strlen(pszSrcPath);
292	if (cchPathAppDocs >= cchPath)
293	supR3HardenedFatal("supR3HardenedPathAppDocs: Buffer overflow, %lu >= %lu\n",
294	(unsigned long)cchPathAppDocs, (unsigned long)cchPath);
295	memcpy(pszPath, pszSrcPath, cchPathAppDocs + 1);
296	return VINF_SUCCESS;
297
298	#else
299	return supR3HardenedPathExecDir(pszPath, cchPath);
300	#endif
301	}
302
303
304	/**
305	* Returns the full path to the executable.
306	*
307	* @returns IPRT status code.
308	* @param pszPath Where to store it.
309	* @param cchPath How big that buffer is.
310	*/
311	static void supR3HardenedGetFullExePath(void)
312	{
313	/*
314	* Get the program filename.
315	*
316	* Most UNIXes have no API for obtaining the executable path, but provides a symbolic
317	* link in the proc file system that tells who was exec'ed. The bad thing about this
318	* is that we have to use readlink, one of the weirder UNIX APIs.
319	*
320	* Darwin, OS/2 and Windows all have proper APIs for getting the program file name.
321	*/
322	#if defined(RT_OS_LINUX) \|\| defined(RT_OS_FREEBSD) \|\| defined(RT_OS_SOLARIS)
323	# ifdef RT_OS_LINUX
324	int cchLink = readlink("/proc/self/exe", &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
325
326	# elif defined(RT_OS_SOLARIS)
327	char szFileBuf[PATH_MAX + 1];
328	sprintf(szFileBuf, "/proc/%ld/path/a.out", (long)getpid());
329	int cchLink = readlink(szFileBuf, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
330
331	# else /* RT_OS_FREEBSD */
332	int aiName[4];
333	aiName[0] = CTL_KERN;
334	aiName[1] = KERN_PROC;
335	aiName[2] = KERN_PROC_PATHNAME;
336	aiName[3] = getpid();
337
338	size_t cbPath = sizeof(g_szSupLibHardenedExePath);
339	if (sysctl(aiName, RT_ELEMENTS(aiName), g_szSupLibHardenedExePath, &cbPath, NULL, 0) < 0)
340	supR3HardenedFatal("supR3HardenedExecDir: sysctl failed\n");
341	g_szSupLibHardenedExePath[sizeof(g_szSupLibHardenedExePath) - 1] = '\0';
342	int cchLink = strlen(g_szSupLibHardenedExePath); /* paranoid? can't we use cbPath? */
343
344	# endif
345	if (cchLink < 0 \|\| cchLink == sizeof(g_szSupLibHardenedExePath) - 1)
346	supR3HardenedFatal("supR3HardenedExecDir: couldn't read \"%s\", errno=%d cchLink=%d\n",
347	g_szSupLibHardenedExePath, errno, cchLink);
348	g_szSupLibHardenedExePath[cchLink] = '\0';
349
350	#elif defined(RT_OS_OS2) \|\| defined(RT_OS_L4)
351	_execname(g_szSupLibHardenedExePath, sizeof(g_szSupLibHardenedExePath));
352
353	#elif defined(RT_OS_DARWIN)
354	const char *pszImageName = _dyld_get_image_name(0);
355	if (!pszImageName)
356	supR3HardenedFatal("supR3HardenedExecDir: _dyld_get_image_name(0) failed\n");
357	size_t cchImageName = strlen(pszImageName);
358	if (!cchImageName \|\| cchImageName >= sizeof(g_szSupLibHardenedExePath))
359	supR3HardenedFatal("supR3HardenedExecDir: _dyld_get_image_name(0) failed, cchImageName=%d\n", cchImageName);
360	memcpy(g_szSupLibHardenedExePath, pszImageName, cchImageName + 1);
361
362	#elif defined(RT_OS_WINDOWS)
363	HMODULE hExe = GetModuleHandle(NULL);
364	if (!GetModuleFileName(hExe, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath)))
365	supR3HardenedFatal("supR3HardenedExecDir: GetModuleFileName failed, rc=%d\n", GetLastError());
366	#else
367	# error needs porting.
368	#endif
369
370	/*
371	* Strip off the filename part (RTPathStripFilename()).
372	*/
373	strcpy(g_szSupLibHardenedDirPath, g_szSupLibHardenedExePath);
374	suplibHardenedPathStripFilename(g_szSupLibHardenedDirPath);
375	}
376
377
378	#ifdef RT_OS_LINUX
379	/**
380	* Checks if we can read /proc/self/exe.
381	*
382	* This is used on linux to see if we have to call init
383	* with program path or not.
384	*
385	* @returns true / false.
386	*/
387	static bool supR3HardenedMainIsProcSelfExeAccssible(void)
388	{
389	char szPath[RTPATH_MAX];
390	int cchLink = readlink("/proc/self/exe", szPath, sizeof(szPath));
391	return cchLink != -1;
392	}
393	#endif /* RT_OS_LINUX */
394
395
396
397	/**
398	* @copydoc RTPathExecDir
399	*/
400	DECLHIDDEN(int) supR3HardenedPathExecDir(char *pszPath, size_t cchPath)
401	{
402	/*
403	* Lazy init (probably not required).
404	*/
405	if (!g_szSupLibHardenedDirPath[0])
406	supR3HardenedGetFullExePath();
407
408	/*
409	* Calc the length and check if there is space before copying.
410	*/
411	size_t cch = strlen(g_szSupLibHardenedDirPath) + 1;
412	if (cch <= cchPath)
413	{
414	memcpy(pszPath, g_szSupLibHardenedDirPath, cch + 1);
415	return VINF_SUCCESS;
416	}
417
418	supR3HardenedFatal("supR3HardenedPathExecDir: Buffer too small (%u < %u)\n", cchPath, cch);
419	return VERR_BUFFER_OVERFLOW;
420	}
421
422
423	DECLHIDDEN(void) supR3HardenedFatalMsgV(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, va_list va)
424	{
425	/*
426	* To the console first, like supR3HardenedFatalV.
427	*/
428	fprintf(stderr, "%s: Error %d in %s!\n", g_pszSupLibHardenedProgName, rc, pszWhere);
429	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
430	va_list vaCopy;
431	va_copy(vaCopy, va);
432	vfprintf(stderr, pszMsgFmt, vaCopy);
433	va_end(vaCopy);
434	fprintf(stderr, "\n");
435
436	switch (enmWhat)
437	{
438	case kSupInitOp_Driver:
439	fprintf(stderr,
440	"\n"
441	"%s: Tip! Make sure the kernel module is loaded. It may also help to reinstall VirtualBox.\n",
442	g_pszSupLibHardenedProgName);
443	break;
444
445	case kSupInitOp_IPRT:
446	case kSupInitOp_Integrity:
447	case kSupInitOp_RootCheck:
448	fprintf(stderr,
449	"\n"
450	"%s: Tip! It may help to reinstall VirtualBox.\n",
451	g_pszSupLibHardenedProgName);
452	break;
453
454	default:
455	/* no hints here */
456	break;
457	}
458
459	#ifdef SUP_HARDENED_SUID
460	/*
461	* Drop any root privileges we might be holding, this won't return
462	* if it fails but end up calling supR3HardenedFatal[V].
463	*/
464	supR3HardenedMainDropPrivileges();
465	#endif /* SUP_HARDENED_SUID */
466
467	/*
468	* Now try resolve and call the TrustedError entry point if we can
469	* find it. We'll fork before we attempt this because that way the
470	* session management in main will see us exiting immediately (if
471	* it's involved with us).
472	*/
473	#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
474	int pid = fork();
475	if (pid <= 0)
476	#endif
477	{
478	PFNSUPTRUSTEDERROR pfnTrustedError = supR3HardenedMainGetTrustedError(g_pszSupLibHardenedProgName);
479	if (pfnTrustedError)
480	pfnTrustedError(pszWhere, enmWhat, rc, pszMsgFmt, va);
481	}
482
483	/*
484	* Quit
485	*/
486	for (;;)
487	#ifdef _MSC_VER
488	exit(1);
489	#else
490	_Exit(1);
491	#endif
492	}
493
494
495	DECLHIDDEN(void) supR3HardenedFatalMsg(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, ...)
496	{
497	va_list va;
498	va_start(va, pszMsgFmt);
499	supR3HardenedFatalMsgV(pszWhere, enmWhat, rc, pszMsgFmt, va);
500	va_end(va);
501	}
502
503
504	DECLHIDDEN(void) supR3HardenedFatalV(const char *pszFormat, va_list va)
505	{
506	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
507	vfprintf(stderr, pszFormat, va);
508	for (;;)
509	#ifdef _MSC_VER
510	exit(1);
511	#else
512	_Exit(1);
513	#endif
514	}
515
516
517	DECLHIDDEN(void) supR3HardenedFatal(const char *pszFormat, ...)
518	{
519	va_list va;
520	va_start(va, pszFormat);
521	supR3HardenedFatalV(pszFormat, va);
522	va_end(va);
523	}
524
525
526	DECLHIDDEN(int) supR3HardenedErrorV(int rc, bool fFatal, const char *pszFormat, va_list va)
527	{
528	if (fFatal)
529	supR3HardenedFatalV(pszFormat, va);
530
531	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
532	vfprintf(stderr, pszFormat, va);
533	return rc;
534	}
535
536
537	DECLHIDDEN(int) supR3HardenedError(int rc, bool fFatal, const char *pszFormat, ...)
538	{
539	va_list va;
540	va_start(va, pszFormat);
541	supR3HardenedErrorV(rc, fFatal, pszFormat, va);
542	va_end(va);
543	return rc;
544	}
545
546
547	/**
548	* Wrapper around snprintf which will throw a fatal error on buffer overflow.
549	*
550	* @returns Number of chars in the result string.
551	* @param pszDst The destination buffer.
552	* @param cchDst The size of the buffer.
553	* @param pszFormat The format string.
554	* @param ... Format arguments.
555	*/
556	static size_t supR3HardenedStrPrintf(char pszDst, size_t cchDst, const char pszFormat, ...)
557	{
558	va_list va;
559	va_start(va, pszFormat);
560	#ifdef _MSC_VER
561	int cch = _vsnprintf(pszDst, cchDst, pszFormat, va);
562	#else
563	int cch = vsnprintf(pszDst, cchDst, pszFormat, va);
564	#endif
565	va_end(va);
566	if ((unsigned)cch >= cchDst \|\| cch < 0)
567	supR3HardenedFatal("supR3HardenedStrPrintf: buffer overflow, %d >= %lu\n", cch, (long)cchDst);
568	return cch;
569	}
570
571
572	/**
573	* Attempts to open /dev/vboxdrv (or equvivalent).
574	*
575	* @remarks This function will not return on failure.
576	*/
577	static void supR3HardenedMainOpenDevice(void)
578	{
579	int rc = suplibOsInit(&g_SupPreInitData.Data, false);
580	if (RT_SUCCESS(rc))
581	return;
582
583	switch (rc)
584	{
585	/** @todo better messages! */
586	case VERR_VM_DRIVER_NOT_INSTALLED:
587	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
588	"Kernel driver not installed");
589	case VERR_VM_DRIVER_NOT_ACCESSIBLE:
590	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
591	"Kernel driver not accessible");
592	case VERR_VM_DRIVER_LOAD_ERROR:
593	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
594	"VERR_VM_DRIVER_LOAD_ERROR");
595	case VERR_VM_DRIVER_OPEN_ERROR:
596	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
597	"VERR_VM_DRIVER_OPEN_ERROR");
598	case VERR_VM_DRIVER_VERSION_MISMATCH:
599	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
600	"Kernel driver version mismatch");
601	case VERR_ACCESS_DENIED:
602	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
603	"VERR_ACCESS_DENIED");
604	case VERR_NO_MEMORY:
605	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
606	"Kernel memory allocation/mapping failed");
607	default:
608	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
609	"Unknown rc=%d", rc);
610	}
611	}
612
613
614	#ifdef SUP_HARDENED_SUID
615
616	/**
617	* Grabs extra non-root capabilities / privileges that we might require.
618	*
619	* This is currently only used for being able to do ICMP from the NAT engine.
620	*
621	* @note We still have root privileges at the time of this call.
622	*/
623	static void supR3HardenedMainGrabCapabilites(void)
624	{
625	# if defined(RT_OS_LINUX)
626	/*
627	* We are about to drop all our privileges. Remove all capabilities but
628	* keep the cap_net_raw capability for ICMP sockets for the NAT stack.
629	*/
630	if (g_uCaps != 0)
631	{
632	# ifdef USE_LIB_PCAP
633	/* XXX cap_net_bind_service */
634	if (!cap_set_proc(cap_from_text("all-eip cap_net_raw+ep")))
635	prctl(PR_SET_KEEPCAPS, 1 /keep=/, 0, 0, 0);
636	prctl(PR_SET_DUMPABLE, 1 /dump/, 0, 0, 0);
637	# else
638	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
639	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
640	memset(hdr, 0, sizeof(*hdr));
641	hdr->version = _LINUX_CAPABILITY_VERSION;
642	memset(cap, 0, sizeof(*cap));
643	cap->effective = g_uCaps;
644	cap->permitted = g_uCaps;
645	if (!capset(hdr, cap))
646	prctl(PR_SET_KEEPCAPS, 1 /keep/, 0, 0, 0);
647	prctl(PR_SET_DUMPABLE, 1 /dump/, 0, 0, 0);
648	# endif /* !USE_LIB_PCAP */
649	}
650
651	# elif defined(RT_OS_SOLARIS)
652	/*
653	* Add net_icmpaccess privilege to effective privileges and limit
654	* permitted privileges before completely dropping root privileges.
655	* This requires dropping root privileges temporarily to get the normal
656	* user's privileges.
657	*/
658	seteuid(g_uid);
659	priv_set_t *pPrivEffective = priv_allocset();
660	priv_set_t *pPrivNew = priv_allocset();
661	if (pPrivEffective && pPrivNew)
662	{
663	int rc = getppriv(PRIV_EFFECTIVE, pPrivEffective);
664	seteuid(0);
665	if (!rc)
666	{
667	priv_copyset(pPrivEffective, pPrivNew);
668	rc = priv_addset(pPrivNew, PRIV_NET_ICMPACCESS);
669	if (!rc)
670	{
671	/* Order is important, as one can't set a privilege which is
672	* not in the permitted privilege set. */
673	rc = setppriv(PRIV_SET, PRIV_EFFECTIVE, pPrivNew);
674	if (rc)
675	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set effective privilege set.\n");
676	rc = setppriv(PRIV_SET, PRIV_PERMITTED, pPrivNew);
677	if (rc)
678	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set permitted privilege set.\n");
679	}
680	else
681	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to add NET_ICMPACCESS privilege.\n");
682	}
683	}
684	else
685	{
686	/* for memory allocation failures just continue */
687	seteuid(0);
688	}
689
690	if (pPrivEffective)
691	priv_freeset(pPrivEffective);
692	if (pPrivNew)
693	priv_freeset(pPrivNew);
694	# endif
695	}
696
697	/*
698	* Look at the environment for some special options.
699	*/
700	static void supR3GrabOptions(void)
701	{
702	const char *pszOpt;
703
704	# ifdef RT_OS_LINUX
705	g_uCaps = 0;
706
707	/*
708	* Do _not_ perform any capability-related system calls for root processes
709	* (leaving g_uCaps at 0).
710	* (Hint: getuid gets the real user id, not the effective.)
711	*/
712	if (getuid() != 0)
713	{
714	/*
715	* CAP_NET_RAW.
716	* Default: enabled.
717	* Can be disabled with 'export VBOX_HARD_CAP_NET_RAW=0'.
718	*/
719	pszOpt = getenv("VBOX_HARD_CAP_NET_RAW");
720	if ( !pszOpt
721	\|\| memcmp(pszOpt, "0", sizeof("0")) != 0)
722	g_uCaps = CAP_TO_MASK(CAP_NET_RAW);
723
724	/*
725	* CAP_NET_BIND_SERVICE.
726	* Default: disabled.
727	* Can be enabled with 'export VBOX_HARD_CAP_NET_BIND_SERVICE=1'.
728	*/
729	pszOpt = getenv("VBOX_HARD_CAP_NET_BIND_SERVICE");
730	if ( pszOpt
731	&& memcmp(pszOpt, "0", sizeof("0")) != 0)
732	g_uCaps \|= CAP_TO_MASK(CAP_NET_BIND_SERVICE);
733	}
734	# endif
735	}
736
737	/**
738	* Drop any root privileges we might be holding.
739	*/
740	static void supR3HardenedMainDropPrivileges(void)
741	{
742	/*
743	* Try use setre[ug]id since this will clear the save uid/gid and thus
744	* leave fewer traces behind that libs like GTK+ may pick up.
745	*/
746	uid_t euid, ruid, suid;
747	gid_t egid, rgid, sgid;
748	# if defined(RT_OS_DARWIN)
749	/* The really great thing here is that setreuid isn't available on
750	OS X 10.4, libc emulates it. While 10.4 have a slightly different and
751	non-standard setuid implementation compared to 10.5, the following
752	works the same way with both version since we're super user (10.5 req).
753	The following will set all three variants of the group and user IDs. */
754	setgid(g_gid);
755	setuid(g_uid);
756	euid = geteuid();
757	ruid = suid = getuid();
758	egid = getegid();
759	rgid = sgid = getgid();
760
761	# elif defined(RT_OS_SOLARIS)
762	/* Solaris doesn't have setresuid, but the setreuid interface is BSD
763	compatible and will set the saved uid to euid when we pass it a ruid
764	that isn't -1 (which we do). */
765	setregid(g_gid, g_gid);
766	setreuid(g_uid, g_uid);
767	euid = geteuid();
768	ruid = suid = getuid();
769	egid = getegid();
770	rgid = sgid = getgid();
771
772	# else
773	/* This is the preferred one, full control no questions about semantics.
774	PORTME: If this isn't work, try join one of two other gangs above. */
775	setresgid(g_gid, g_gid, g_gid);
776	setresuid(g_uid, g_uid, g_uid);
777	if (getresuid(&ruid, &euid, &suid) != 0)
778	{
779	euid = geteuid();
780	ruid = suid = getuid();
781	}
782	if (getresgid(&rgid, &egid, &sgid) != 0)
783	{
784	egid = getegid();
785	rgid = sgid = getgid();
786	}
787	# endif
788
789
790	/* Check that it worked out all right. */
791	if ( euid != g_uid
792	\|\| ruid != g_uid
793	\|\| suid != g_uid
794	\|\| egid != g_gid
795	\|\| rgid != g_gid
796	\|\| sgid != g_gid)
797	supR3HardenedFatal("SUPR3HardenedMain: failed to drop root privileges!"
798	" (euid=%d ruid=%d suid=%d egid=%d rgid=%d sgid=%d; wanted uid=%d and gid=%d)\n",
799	euid, ruid, suid, egid, rgid, sgid, g_uid, g_gid);
800
801	# if RT_OS_LINUX
802	/*
803	* Re-enable the cap_net_raw capability which was disabled during setresuid.
804	*/
805	if (g_uCaps != 0)
806	{
807	# ifdef USE_LIB_PCAP
808	/** @todo Warn if that does not work? */
809	/* XXX cap_net_bind_service */
810	cap_set_proc(cap_from_text("cap_net_raw+ep"));
811	# else
812	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
813	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
814	memset(hdr, 0, sizeof(*hdr));
815	hdr->version = _LINUX_CAPABILITY_VERSION;
816	memset(cap, 0, sizeof(*cap));
817	cap->effective = g_uCaps;
818	cap->permitted = g_uCaps;
819	/** @todo Warn if that does not work? */
820	capset(hdr, cap);
821	# endif /* !USE_LIB_PCAP */
822	}
823	# endif
824	}
825
826	#endif /* SUP_HARDENED_SUID */
827
828	/**
829	* Loads the VBoxRT DLL/SO/DYLIB, hands it the open driver,
830	* and calls RTR3InitEx.
831	*
832	* @param fFlags The SUPR3HardenedMain fFlags argument, passed to supR3PreInit.
833	*
834	* @remarks VBoxRT contains both IPRT and SUPR3.
835	* @remarks This function will not return on failure.
836	*/
837	static void supR3HardenedMainInitRuntime(uint32_t fFlags)
838	{
839	/*
840	* Construct the name.
841	*/
842	char szPath[RTPATH_MAX];
843	supR3HardenedPathSharedLibs(szPath, sizeof(szPath) - sizeof("/VBoxRT" SUPLIB_DLL_SUFF));
844	strcat(szPath, "/VBoxRT" SUPLIB_DLL_SUFF);
845
846	/*
847	* Open it and resolve the symbols.
848	*/
849	#if defined(RT_OS_WINDOWS)
850	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
851	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
852	if (!hMod)
853	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
854	"LoadLibraryEx(\"%s\",,) failed (rc=%d)",
855	szPath, GetLastError());
856	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)GetProcAddress(hMod, SUP_HARDENED_SYM("RTR3InitEx"));
857	if (!pfnRTInitEx)
858	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
859	"Entrypoint \"RTR3InitEx\" not found in \"%s\" (rc=%d)",
860	szPath, GetLastError());
861
862	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)GetProcAddress(hMod, SUP_HARDENED_SYM("supR3PreInit"));
863	if (!pfnSUPPreInit)
864	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
865	"Entrypoint \"supR3PreInit\" not found in \"%s\" (rc=%d)",
866	szPath, GetLastError());
867
868	#else
869	/* the dlopen crowd */
870	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
871	if (!pvMod)
872	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
873	"dlopen(\"%s\",) failed: %s",
874	szPath, dlerror());
875	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("RTR3InitEx"));
876	if (!pfnRTInitEx)
877	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
878	"Entrypoint \"RTR3InitEx\" not found in \"%s\"!\ndlerror: %s",
879	szPath, dlerror());
880	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("supR3PreInit"));
881	if (!pfnSUPPreInit)
882	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
883	"Entrypoint \"supR3PreInit\" not found in \"%s\"!\ndlerror: %s",
884	szPath, dlerror());
885	#endif
886
887	/*
888	* Make the calls.
889	*/
890	supR3HardenedGetPreInitData(&g_SupPreInitData);
891	int rc = pfnSUPPreInit(&g_SupPreInitData, fFlags);
892	if (RT_FAILURE(rc))
893	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
894	"supR3PreInit failed with rc=%d", rc);
895	const char *pszExePath = NULL;
896	#ifdef RT_OS_LINUX
897	if (!supR3HardenedMainIsProcSelfExeAccssible())
898	pszExePath = g_szSupLibHardenedExePath;
899	#endif
900	rc = pfnRTInitEx(RTR3INIT_VER_1,
901	fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV ? 0 : RTR3INIT_FLAGS_SUPLIB,
902	0 /cArgs/, NULL /papszArgs/, pszExePath);
903	if (RT_FAILURE(rc))
904	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
905	"RTR3InitEx failed with rc=%d", rc);
906	}
907
908
909	/**
910	* Loads the DLL/SO/DYLIB containing the actual program and
911	* resolves the TrustedError symbol.
912	*
913	* This is very similar to supR3HardenedMainGetTrustedMain().
914	*
915	* @returns Pointer to the trusted error symbol if it is exported, NULL
916	* and no error messages otherwise.
917	* @param pszProgName The program name.
918	*/
919	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName)
920	{
921	/*
922	* Construct the name.
923	*/
924	char szPath[RTPATH_MAX];
925	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
926	size_t cch = strlen(szPath);
927	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
928
929	/*
930	* Open it and resolve the symbol.
931	*/
932	#if defined(RT_OS_WINDOWS)
933	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
934	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
935	if (!hMod)
936	return NULL;
937	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedError"));
938	if (!pfn)
939	return NULL;
940	return (PFNSUPTRUSTEDERROR)pfn;
941
942	#else
943	/* the dlopen crowd */
944	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
945	if (!pvMod)
946	return NULL;
947	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedError"));
948	if (!pvSym)
949	return NULL;
950	return (PFNSUPTRUSTEDERROR)(uintptr_t)pvSym;
951	#endif
952	}
953
954
955	/**
956	* Loads the DLL/SO/DYLIB containing the actual program and
957	* resolves the TrustedMain symbol.
958	*
959	* @returns Pointer to the trusted main of the actual program.
960	* @param pszProgName The program name.
961	* @remarks This function will not return on failure.
962	*/
963	static PFNSUPTRUSTEDMAIN supR3HardenedMainGetTrustedMain(const char *pszProgName)
964	{
965	/*
966	* Construct the name.
967	*/
968	char szPath[RTPATH_MAX];
969	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
970	size_t cch = strlen(szPath);
971	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
972
973	/*
974	* Open it and resolve the symbol.
975	*/
976	#if defined(RT_OS_WINDOWS)
977	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
978	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
979	if (!hMod)
980	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: LoadLibraryEx(\"%s\",,) failed, rc=%d\n",
981	szPath, GetLastError());
982	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedMain"));
983	if (!pfn)
984	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\" (rc=%d)\n",
985	szPath, GetLastError());
986	return (PFNSUPTRUSTEDMAIN)pfn;
987
988	#else
989	/* the dlopen crowd */
990	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
991	if (!pvMod)
992	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: dlopen(\"%s\",) failed: %s\n",
993	szPath, dlerror());
994	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedMain"));
995	if (!pvSym)
996	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\"!\ndlerror: %s\n",
997	szPath, dlerror());
998	return (PFNSUPTRUSTEDMAIN)(uintptr_t)pvSym;
999	#endif
1000	}
1001
1002
1003	/**
1004	* Secure main.
1005	*
1006	* This is used for the set-user-ID-on-execute binaries on unixy systems
1007	* and when using the open-vboxdrv-via-root-service setup on Windows.
1008	*
1009	* This function will perform the integrity checks of the VirtualBox
1010	* installation, open the support driver, open the root service (later),
1011	* and load the DLL corresponding to \a pszProgName and execute its main
1012	* function.
1013	*
1014	* @returns Return code appropriate for main().
1015	*
1016	* @param pszProgName The program name. This will be used to figure out which
1017	* DLL/SO/DYLIB to load and execute.
1018	* @param fFlags Flags.
1019	* @param argc The argument count.
1020	* @param argv The argument vector.
1021	* @param envp The environment vector.
1022	*/
1023	DECLHIDDEN(int) SUPR3HardenedMain(const char pszProgName, uint32_t fFlags, int argc, char argv, char *envp)
1024	{
1025	/*
1026	* Note! At this point there is no IPRT, so we will have to stick
1027	* to basic CRT functions that everyone agree upon.
1028	*/
1029	g_pszSupLibHardenedProgName = pszProgName;
1030	g_SupPreInitData.u32Magic = SUPPREINITDATA_MAGIC;
1031	g_SupPreInitData.Data.hDevice = SUP_HDEVICE_NIL;
1032	g_SupPreInitData.u32EndMagic = SUPPREINITDATA_MAGIC;
1033
1034	#ifdef SUP_HARDENED_SUID
1035	# ifdef RT_OS_LINUX
1036	/*
1037	* On linux we have to make sure the path is initialized because we
1038	* might not be able to access /proc/self/exe after the seteuid call.
1039	*/
1040	supR3HardenedGetFullExePath();
1041
1042	# endif
1043
1044	/*
1045	* Grab any options from the environment.
1046	*/
1047	supR3GrabOptions();
1048
1049	/*
1050	* Check that we're root, if we aren't then the installation is butchered.
1051	*/
1052	g_uid = getuid();
1053	g_gid = getgid();
1054	if (geteuid() != 0 /* root */)
1055	supR3HardenedFatalMsg("SUPR3HardenedMain", kSupInitOp_RootCheck, VERR_PERMISSION_DENIED,
1056	"Effective UID is not root (euid=%d egid=%d uid=%d gid=%d)",
1057	geteuid(), getegid(), g_uid, g_gid);
1058	#endif
1059
1060	/*
1061	* Validate the installation.
1062	*/
1063	supR3HardenedVerifyAll(true /* fFatal /, false / fLeaveFilesOpen */, pszProgName);
1064
1065	/*
1066	* Open the vboxdrv device.
1067	*/
1068	if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV))
1069	supR3HardenedMainOpenDevice();
1070
1071	/*
1072	* Open the root service connection.
1073	*/
1074	//if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_SVC))
1075	//supR3HardenedMainOpenService(&g_SupPreInitData, true /* fFatal */);
1076
1077	#ifdef SUP_HARDENED_SUID
1078	/*
1079	* Grab additional capabilities / privileges.
1080	*/
1081	supR3HardenedMainGrabCapabilites();
1082
1083	/*
1084	* Drop any root privileges we might be holding (won't return on failure)
1085	*/
1086	supR3HardenedMainDropPrivileges();
1087	#endif
1088
1089	/*
1090	* Load the IPRT, hand the SUPLib part the open driver and
1091	* call RTR3InitEx.
1092	*/
1093	supR3HardenedMainInitRuntime(fFlags);
1094
1095	/*
1096	* Load the DLL/SO/DYLIB containing the actual program
1097	* and pass control to it.
1098	*/
1099	PFNSUPTRUSTEDMAIN pfnTrustedMain = supR3HardenedMainGetTrustedMain(pszProgName);
1100	return pfnTrustedMain(argc, argv, envp);
1101	}
1102

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source: vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp@ 38895

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