SUPR3HardenedMain.cpp@ 37233

Last change on this file since 37233 was 35311, checked in by vboxsync, 14 years ago
UPR3HardenedMain.cpp: next attempt at getting Solaris privileges working correctly
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1	/* $Id: SUPR3HardenedMain.cpp 35311 2010-12-23 14:13:30Z 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/param.h>
82
83	#include "SUPLibInternal.h"
84
85
86	/*******************************************************************************
87	* Defined Constants And Macros *
88	*******************************************************************************/
89	/** @def SUP_HARDENED_SUID
90	* Whether we're employing set-user-ID-on-execute in the hardening.
91	*/
92	#if !defined(RT_OS_OS2) && !defined(RT_OS_WINDOWS) && !defined(RT_OS_L4)
93	# define SUP_HARDENED_SUID
94	#else
95	# undef SUP_HARDENED_SUID
96	#endif
97
98	/** @def SUP_HARDENED_SYM
99	* Decorate a symbol that's resolved dynamically.
100	*/
101	#ifdef RT_OS_OS2
102	# define SUP_HARDENED_SYM(sym) "_" sym
103	#else
104	# define SUP_HARDENED_SYM(sym) sym
105	#endif
106
107
108	/*******************************************************************************
109	* Structures and Typedefs *
110	*******************************************************************************/
111	/** @see RTR3InitEx */
112	typedef DECLCALLBACK(int) FNRTR3INITEX(uint32_t iVersion, const char *pszProgramPath, bool fInitSUPLib);
113	typedef FNRTR3INITEX *PFNRTR3INITEX;
114
115
116	/*******************************************************************************
117	* Global Variables *
118	*******************************************************************************/
119	/** The pre-init data we pass on to SUPR3 (residing in VBoxRT). */
120	static SUPPREINITDATA g_SupPreInitData;
121	/** The program executable path. */
122	static char g_szSupLibHardenedExePath[RTPATH_MAX];
123	/** The program directory path. */
124	static char g_szSupLibHardenedDirPath[RTPATH_MAX];
125
126	/** The program name. */
127	static const char *g_pszSupLibHardenedProgName;
128
129	#ifdef SUP_HARDENED_SUID
130	/** The real UID at startup. */
131	static uid_t g_uid;
132	/** The real GID at startup. */
133	static gid_t g_gid;
134	# ifdef RT_OS_LINUX
135	static uint32_t g_uCaps;
136	# endif
137	#endif
138
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 supR3HardenedPathExecDir(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 supR3HardenedPathExecDir(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 supR3HardenedPathExecDir(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 supR3HardenedPathExecDir(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
324	# elif defined(RT_OS_SOLARIS)
325	char szFileBuf[PATH_MAX + 1];
326	sprintf(szFileBuf, "/proc/%ld/path/a.out", (long)getpid());
327	int cchLink = readlink(szFileBuf, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
328
329	# else /* RT_OS_FREEBSD */
330	int aiName[4];
331	aiName[0] = CTL_KERN;
332	aiName[1] = KERN_PROC;
333	aiName[2] = KERN_PROC_PATHNAME;
334	aiName[3] = getpid();
335
336	size_t cbPath = sizeof(g_szSupLibHardenedExePath);
337	if (sysctl(aiName, RT_ELEMENTS(aiName), g_szSupLibHardenedExePath, &cbPath, NULL, 0) < 0)
338	supR3HardenedFatal("supR3HardenedExecDir: sysctl failed\n");
339	g_szSupLibHardenedExePath[sizeof(g_szSupLibHardenedExePath) - 1] = '\0';
340	int cchLink = strlen(g_szSupLibHardenedExePath); /* paranoid? can't we use cbPath? */
341
342	# endif
343	if (cchLink < 0 \|\| cchLink == sizeof(g_szSupLibHardenedExePath) - 1)
344	supR3HardenedFatal("supR3HardenedExecDir: couldn't read \"%s\", errno=%d cchLink=%d\n",
345	g_szSupLibHardenedExePath, errno, cchLink);
346	g_szSupLibHardenedExePath[cchLink] = '\0';
347
348	#elif defined(RT_OS_OS2) \|\| defined(RT_OS_L4)
349	_execname(g_szSupLibHardenedExePath, sizeof(g_szSupLibHardenedExePath));
350
351	#elif defined(RT_OS_DARWIN)
352	const char *pszImageName = _dyld_get_image_name(0);
353	if (!pszImageName)
354	supR3HardenedFatal("supR3HardenedExecDir: _dyld_get_image_name(0) failed\n");
355	size_t cchImageName = strlen(pszImageName);
356	if (!cchImageName \|\| cchImageName >= sizeof(g_szSupLibHardenedExePath))
357	supR3HardenedFatal("supR3HardenedExecDir: _dyld_get_image_name(0) failed, cchImageName=%d\n", cchImageName);
358	memcpy(g_szSupLibHardenedExePath, pszImageName, cchImageName + 1);
359
360	#elif defined(RT_OS_WINDOWS)
361	HMODULE hExe = GetModuleHandle(NULL);
362	if (!GetModuleFileName(hExe, &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath)))
363	supR3HardenedFatal("supR3HardenedExecDir: GetModuleFileName failed, rc=%d\n", GetLastError());
364	#else
365	# error needs porting.
366	#endif
367
368	/*
369	* Strip off the filename part (RTPathStripFilename()).
370	*/
371	strcpy(g_szSupLibHardenedDirPath, g_szSupLibHardenedExePath);
372	suplibHardenedPathStripFilename(g_szSupLibHardenedDirPath);
373	}
374
375
376	#ifdef RT_OS_LINUX
377	/**
378	* Checks if we can read /proc/self/exe.
379	*
380	* This is used on linux to see if we have to call init
381	* with program path or not.
382	*
383	* @returns true / false.
384	*/
385	static bool supR3HardenedMainIsProcSelfExeAccssible(void)
386	{
387	char szPath[RTPATH_MAX];
388	int cchLink = readlink("/proc/self/exe", szPath, sizeof(szPath));
389	return cchLink != -1;
390	}
391	#endif /* RT_OS_LINUX */
392
393
394
395	/**
396	* @copydoc RTPathExecDir
397	*/
398	DECLHIDDEN(int) supR3HardenedPathExecDir(char *pszPath, size_t cchPath)
399	{
400	/*
401	* Lazy init (probably not required).
402	*/
403	if (!g_szSupLibHardenedDirPath[0])
404	supR3HardenedGetFullExePath();
405
406	/*
407	* Calc the length and check if there is space before copying.
408	*/
409	size_t cch = strlen(g_szSupLibHardenedDirPath) + 1;
410	if (cch <= cchPath)
411	{
412	memcpy(pszPath, g_szSupLibHardenedDirPath, cch + 1);
413	return VINF_SUCCESS;
414	}
415
416	supR3HardenedFatal("supR3HardenedPathExecDir: Buffer too small (%u < %u)\n", cchPath, cch);
417	return VERR_BUFFER_OVERFLOW;
418	}
419
420
421	DECLHIDDEN(void) supR3HardenedFatalMsgV(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, va_list va)
422	{
423	/*
424	* To the console first, like supR3HardenedFatalV.
425	*/
426	fprintf(stderr, "%s: Error %d in %s!\n", g_pszSupLibHardenedProgName, rc, pszWhere);
427	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
428	va_list vaCopy;
429	va_copy(vaCopy, va);
430	vfprintf(stderr, pszMsgFmt, vaCopy);
431	va_end(vaCopy);
432	fprintf(stderr, "\n");
433
434	switch (enmWhat)
435	{
436	case kSupInitOp_Driver:
437	fprintf(stderr,
438	"\n"
439	"%s: Tip! Make sure the kernel module is loaded. It may also help to reinstall VirtualBox.\n",
440	g_pszSupLibHardenedProgName);
441	break;
442
443	case kSupInitOp_IPRT:
444	case kSupInitOp_Integrity:
445	case kSupInitOp_RootCheck:
446	fprintf(stderr,
447	"\n"
448	"%s: Tip! It may help to reinstall VirtualBox.\n",
449	g_pszSupLibHardenedProgName);
450	break;
451
452	default:
453	/* no hints here */
454	break;
455	}
456
457	#ifdef SUP_HARDENED_SUID
458	/*
459	* Drop any root privileges we might be holding, this won't return
460	* if it fails but end up calling supR3HardenedFatal[V].
461	*/
462	supR3HardenedMainDropPrivileges();
463	#endif /* SUP_HARDENED_SUID */
464
465	/*
466	* Now try resolve and call the TrustedError entry point if we can
467	* find it. We'll fork before we attempt this because that way the
468	* session management in main will see us exiting immediately (if
469	* it's involved with us).
470	*/
471	#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
472	int pid = fork();
473	if (pid <= 0)
474	#endif
475	{
476	PFNSUPTRUSTEDERROR pfnTrustedError = supR3HardenedMainGetTrustedError(g_pszSupLibHardenedProgName);
477	if (pfnTrustedError)
478	pfnTrustedError(pszWhere, enmWhat, rc, pszMsgFmt, va);
479	}
480
481	/*
482	* Quit
483	*/
484	for (;;)
485	#ifdef _MSC_VER
486	exit(1);
487	#else
488	_Exit(1);
489	#endif
490	}
491
492
493	DECLHIDDEN(void) supR3HardenedFatalMsg(const char pszWhere, SUPINITOP enmWhat, int rc, const char pszMsgFmt, ...)
494	{
495	va_list va;
496	va_start(va, pszMsgFmt);
497	supR3HardenedFatalMsgV(pszWhere, enmWhat, rc, pszMsgFmt, va);
498	va_end(va);
499	}
500
501
502	DECLHIDDEN(void) supR3HardenedFatalV(const char *pszFormat, va_list va)
503	{
504	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
505	vfprintf(stderr, pszFormat, va);
506	for (;;)
507	#ifdef _MSC_VER
508	exit(1);
509	#else
510	_Exit(1);
511	#endif
512	}
513
514
515	DECLHIDDEN(void) supR3HardenedFatal(const char *pszFormat, ...)
516	{
517	va_list va;
518	va_start(va, pszFormat);
519	supR3HardenedFatalV(pszFormat, va);
520	va_end(va);
521	}
522
523
524	DECLHIDDEN(int) supR3HardenedErrorV(int rc, bool fFatal, const char *pszFormat, va_list va)
525	{
526	if (fFatal)
527	supR3HardenedFatalV(pszFormat, va);
528
529	fprintf(stderr, "%s: ", g_pszSupLibHardenedProgName);
530	vfprintf(stderr, pszFormat, va);
531	return rc;
532	}
533
534
535	DECLHIDDEN(int) supR3HardenedError(int rc, bool fFatal, const char *pszFormat, ...)
536	{
537	va_list va;
538	va_start(va, pszFormat);
539	supR3HardenedErrorV(rc, fFatal, pszFormat, va);
540	va_end(va);
541	return rc;
542	}
543
544
545	/**
546	* Wrapper around snprintf which will throw a fatal error on buffer overflow.
547	*
548	* @returns Number of chars in the result string.
549	* @param pszDst The destination buffer.
550	* @param cchDst The size of the buffer.
551	* @param pszFormat The format string.
552	* @param ... Format arguments.
553	*/
554	static size_t supR3HardenedStrPrintf(char pszDst, size_t cchDst, const char pszFormat, ...)
555	{
556	va_list va;
557	va_start(va, pszFormat);
558	#ifdef _MSC_VER
559	int cch = _vsnprintf(pszDst, cchDst, pszFormat, va);
560	#else
561	int cch = vsnprintf(pszDst, cchDst, pszFormat, va);
562	#endif
563	va_end(va);
564	if ((unsigned)cch >= cchDst \|\| cch < 0)
565	supR3HardenedFatal("supR3HardenedStrPrintf: buffer overflow, %d >= %lu\n", cch, (long)cchDst);
566	return cch;
567	}
568
569
570	/**
571	* Attempts to open /dev/vboxdrv (or equvivalent).
572	*
573	* @remarks This function will not return on failure.
574	*/
575	static void supR3HardenedMainOpenDevice(void)
576	{
577	int rc = suplibOsInit(&g_SupPreInitData.Data, false);
578	if (RT_SUCCESS(rc))
579	return;
580
581	switch (rc)
582	{
583	/** @todo better messages! */
584	case VERR_VM_DRIVER_NOT_INSTALLED:
585	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
586	"Kernel driver not installed");
587	case VERR_VM_DRIVER_NOT_ACCESSIBLE:
588	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
589	"Kernel driver not accessible");
590	case VERR_VM_DRIVER_LOAD_ERROR:
591	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
592	"VERR_VM_DRIVER_LOAD_ERROR");
593	case VERR_VM_DRIVER_OPEN_ERROR:
594	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
595	"VERR_VM_DRIVER_OPEN_ERROR");
596	case VERR_VM_DRIVER_VERSION_MISMATCH:
597	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
598	"Kernel driver version mismatch");
599	case VERR_ACCESS_DENIED:
600	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
601	"VERR_ACCESS_DENIED");
602	case VERR_NO_MEMORY:
603	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
604	"Kernel memory allocation/mapping failed");
605	default:
606	supR3HardenedFatalMsg("suplibOsInit", kSupInitOp_Driver, rc,
607	"Unknown rc=%d", rc);
608	}
609	}
610
611
612	#ifdef SUP_HARDENED_SUID
613
614	/**
615	* Grabs extra non-root capabilities / privileges that we might require.
616	*
617	* This is currently only used for being able to do ICMP from the NAT engine.
618	*
619	* @note We still have root privileges at the time of this call.
620	*/
621	static void supR3HardenedMainGrabCapabilites(void)
622	{
623	# if defined(RT_OS_LINUX)
624	/*
625	* We are about to drop all our privileges. Remove all capabilities but
626	* keep the cap_net_raw capability for ICMP sockets for the NAT stack.
627	*/
628	if (g_uCaps != 0)
629	{
630	# ifdef USE_LIB_PCAP
631	/* XXX cap_net_bind_service */
632	if (!cap_set_proc(cap_from_text("all-eip cap_net_raw+ep")))
633	prctl(PR_SET_KEEPCAPS, 1 /keep=/, 0, 0, 0);
634	prctl(PR_SET_DUMPABLE, 1 /dump/, 0, 0, 0);
635	# else
636	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
637	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
638	memset(hdr, 0, sizeof(*hdr));
639	hdr->version = _LINUX_CAPABILITY_VERSION;
640	memset(cap, 0, sizeof(*cap));
641	cap->effective = g_uCaps;
642	cap->permitted = g_uCaps;
643	if (!capset(hdr, cap))
644	prctl(PR_SET_KEEPCAPS, 1 /keep/, 0, 0, 0);
645	prctl(PR_SET_DUMPABLE, 1 /dump/, 0, 0, 0);
646	# endif /* !USE_LIB_PCAP */
647	}
648
649	# elif defined(RT_OS_SOLARIS)
650	/*
651	* Add net_icmpaccess privilege to effective privileges and limit
652	* permitted privileges before completely dropping root privileges.
653	* This requires dropping root privileges temporarily to get the normal
654	* user's privileges.
655	*/
656	seteuid(g_uid);
657	priv_set_t *pPrivEffective = priv_allocset();
658	priv_set_t *pPrivNew = priv_allocset();
659	if (pPrivEffective && pPrivNew)
660	{
661	int rc = getppriv(PRIV_EFFECTIVE, pPrivEffective);
662	seteuid(0);
663	if (!rc)
664	{
665	priv_copyset(pPrivEffective, pPrivNew);
666	rc = priv_addset(pPrivNew, PRIV_NET_ICMPACCESS);
667	if (!rc)
668	{
669	/* Order is important, as one can't set a privilege which is
670	* not in the permitted privilege set. */
671	rc = setppriv(PRIV_SET, PRIV_EFFECTIVE, pPrivNew);
672	if (rc)
673	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set effective privilege set.\n");
674	rc = setppriv(PRIV_SET, PRIV_PERMITTED, pPrivNew);
675	if (rc)
676	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set permitted privilege set.\n");
677	}
678	else
679	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to add NET_ICMPACCESS privilege.\n");
680	}
681	}
682	else
683	{
684	/* for memory allocation failures just continue */
685	seteuid(0);
686	}
687	# endif
688	}
689
690	/*
691	* Look at the environment for some special options.
692	*/
693	static void supR3GrabOptions(void)
694	{
695	const char *pszOpt;
696
697	# ifdef RT_OS_LINUX
698	g_uCaps = 0;
699
700	/*
701	* Do _not_ perform any capability-related system calls for root processes
702	* (leaving g_uCaps at 0).
703	* (Hint: getuid gets the real user id, not the effective.)
704	*/
705	if (getuid() != 0)
706	{
707	/*
708	* CAP_NET_RAW.
709	* Default: enabled.
710	* Can be disabled with 'export VBOX_HARD_CAP_NET_RAW=0'.
711	*/
712	pszOpt = getenv("VBOX_HARD_CAP_NET_RAW");
713	if ( !pszOpt
714	\|\| memcmp(pszOpt, "0", sizeof("0")) != 0)
715	g_uCaps = CAP_TO_MASK(CAP_NET_RAW);
716
717	/*
718	* CAP_NET_BIND_SERVICE.
719	* Default: disabled.
720	* Can be enabled with 'export VBOX_HARD_CAP_NET_BIND_SERVICE=1'.
721	*/
722	pszOpt = getenv("VBOX_HARD_CAP_NET_BIND_SERVICE");
723	if ( pszOpt
724	&& memcmp(pszOpt, "0", sizeof("0")) != 0)
725	g_uCaps \|= CAP_TO_MASK(CAP_NET_BIND_SERVICE);
726	}
727	# endif
728	}
729
730	/**
731	* Drop any root privileges we might be holding.
732	*/
733	static void supR3HardenedMainDropPrivileges(void)
734	{
735	/*
736	* Try use setre[ug]id since this will clear the save uid/gid and thus
737	* leave fewer traces behind that libs like GTK+ may pick up.
738	*/
739	uid_t euid, ruid, suid;
740	gid_t egid, rgid, sgid;
741	# if defined(RT_OS_DARWIN)
742	/* The really great thing here is that setreuid isn't available on
743	OS X 10.4, libc emulates it. While 10.4 have a slightly different and
744	non-standard setuid implementation compared to 10.5, the following
745	works the same way with both version since we're super user (10.5 req).
746	The following will set all three variants of the group and user IDs. */
747	setgid(g_gid);
748	setuid(g_uid);
749	euid = geteuid();
750	ruid = suid = getuid();
751	egid = getegid();
752	rgid = sgid = getgid();
753
754	# elif defined(RT_OS_SOLARIS)
755	/* Solaris doesn't have setresuid, but the setreuid interface is BSD
756	compatible and will set the saved uid to euid when we pass it a ruid
757	that isn't -1 (which we do). */
758	setregid(g_gid, g_gid);
759	setreuid(g_uid, g_uid);
760	euid = geteuid();
761	ruid = suid = getuid();
762	egid = getegid();
763	rgid = sgid = getgid();
764
765	# else
766	/* This is the preferred one, full control no questions about semantics.
767	PORTME: If this isn't work, try join one of two other gangs above. */
768	setresgid(g_gid, g_gid, g_gid);
769	setresuid(g_uid, g_uid, g_uid);
770	if (getresuid(&ruid, &euid, &suid) != 0)
771	{
772	euid = geteuid();
773	ruid = suid = getuid();
774	}
775	if (getresgid(&rgid, &egid, &sgid) != 0)
776	{
777	egid = getegid();
778	rgid = sgid = getgid();
779	}
780	# endif
781
782
783	/* Check that it worked out all right. */
784	if ( euid != g_uid
785	\|\| ruid != g_uid
786	\|\| suid != g_uid
787	\|\| egid != g_gid
788	\|\| rgid != g_gid
789	\|\| sgid != g_gid)
790	supR3HardenedFatal("SUPR3HardenedMain: failed to drop root privileges!"
791	" (euid=%d ruid=%d suid=%d egid=%d rgid=%d sgid=%d; wanted uid=%d and gid=%d)\n",
792	euid, ruid, suid, egid, rgid, sgid, g_uid, g_gid);
793
794	# if RT_OS_LINUX
795	/*
796	* Re-enable the cap_net_raw capability which was disabled during setresuid.
797	*/
798	if (g_uCaps != 0)
799	{
800	# ifdef USE_LIB_PCAP
801	/** @todo Warn if that does not work? */
802	/* XXX cap_net_bind_service */
803	cap_set_proc(cap_from_text("cap_net_raw+ep"));
804	# else
805	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
806	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
807	memset(hdr, 0, sizeof(*hdr));
808	hdr->version = _LINUX_CAPABILITY_VERSION;
809	memset(cap, 0, sizeof(*cap));
810	cap->effective = g_uCaps;
811	cap->permitted = g_uCaps;
812	/** @todo Warn if that does not work? */
813	capset(hdr, cap);
814	# endif /* !USE_LIB_PCAP */
815	}
816	# endif
817	}
818
819	#endif /* SUP_HARDENED_SUID */
820
821	/**
822	* Loads the VBoxRT DLL/SO/DYLIB, hands it the open driver,
823	* and calls RTR3Init.
824	*
825	* @param fFlags The SUPR3HardenedMain fFlags argument, passed to supR3PreInit.
826	*
827	* @remarks VBoxRT contains both IPRT and SUPR3.
828	* @remarks This function will not return on failure.
829	*/
830	static void supR3HardenedMainInitRuntime(uint32_t fFlags)
831	{
832	/*
833	* Construct the name.
834	*/
835	char szPath[RTPATH_MAX];
836	supR3HardenedPathSharedLibs(szPath, sizeof(szPath) - sizeof("/VBoxRT" SUPLIB_DLL_SUFF));
837	strcat(szPath, "/VBoxRT" SUPLIB_DLL_SUFF);
838
839	/*
840	* Open it and resolve the symbols.
841	*/
842	#if defined(RT_OS_WINDOWS)
843	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
844	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
845	if (!hMod)
846	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
847	"LoadLibraryEx(\"%s\",,) failed (rc=%d)",
848	szPath, GetLastError());
849	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)GetProcAddress(hMod, SUP_HARDENED_SYM("RTR3InitEx"));
850	if (!pfnRTInitEx)
851	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
852	"Entrypoint \"RTR3InitEx\" not found in \"%s\" (rc=%d)",
853	szPath, GetLastError());
854
855	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)GetProcAddress(hMod, SUP_HARDENED_SYM("supR3PreInit"));
856	if (!pfnSUPPreInit)
857	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
858	"Entrypoint \"supR3PreInit\" not found in \"%s\" (rc=%d)",
859	szPath, GetLastError());
860
861	#else
862	/* the dlopen crowd */
863	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
864	if (!pvMod)
865	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
866	"dlopen(\"%s\",) failed: %s",
867	szPath, dlerror());
868	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("RTR3InitEx"));
869	if (!pfnRTInitEx)
870	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
871	"Entrypoint \"RTR3InitEx\" not found in \"%s\"!\ndlerror: %s",
872	szPath, dlerror());
873	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("supR3PreInit"));
874	if (!pfnSUPPreInit)
875	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
876	"Entrypoint \"supR3PreInit\" not found in \"%s\"!\ndlerror: %s",
877	szPath, dlerror());
878	#endif
879
880	/*
881	* Make the calls.
882	*/
883	supR3HardenedGetPreInitData(&g_SupPreInitData);
884	int rc = pfnSUPPreInit(&g_SupPreInitData, fFlags);
885	if (RT_FAILURE(rc))
886	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
887	"supR3PreInit failed with rc=%d", rc);
888	const char *pszExePath = NULL;
889	#ifdef RT_OS_LINUX
890	if (!supR3HardenedMainIsProcSelfExeAccssible())
891	pszExePath = g_szSupLibHardenedExePath;
892	#endif
893	rc = pfnRTInitEx(0, pszExePath, !(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV));
894	if (RT_FAILURE(rc))
895	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
896	"RTR3Init failed with rc=%d", rc);
897	}
898
899
900	/**
901	* Loads the DLL/SO/DYLIB containing the actual program and
902	* resolves the TrustedError symbol.
903	*
904	* This is very similar to supR3HardenedMainGetTrustedMain().
905	*
906	* @returns Pointer to the trusted error symbol if it is exported, NULL
907	* and no error messages otherwise.
908	* @param pszProgName The program name.
909	*/
910	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName)
911	{
912	/*
913	* Construct the name.
914	*/
915	char szPath[RTPATH_MAX];
916	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
917	size_t cch = strlen(szPath);
918	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
919
920	/*
921	* Open it and resolve the symbol.
922	*/
923	#if defined(RT_OS_WINDOWS)
924	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
925	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
926	if (!hMod)
927	return NULL;
928	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedError"));
929	if (!pfn)
930	return NULL;
931	return (PFNSUPTRUSTEDERROR)pfn;
932
933	#else
934	/* the dlopen crowd */
935	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
936	if (!pvMod)
937	return NULL;
938	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedError"));
939	if (!pvSym)
940	return NULL;
941	return (PFNSUPTRUSTEDERROR)(uintptr_t)pvSym;
942	#endif
943	}
944
945
946	/**
947	* Loads the DLL/SO/DYLIB containing the actual program and
948	* resolves the TrustedMain symbol.
949	*
950	* @returns Pointer to the trusted main of the actual program.
951	* @param pszProgName The program name.
952	* @remarks This function will not return on failure.
953	*/
954	static PFNSUPTRUSTEDMAIN supR3HardenedMainGetTrustedMain(const char *pszProgName)
955	{
956	/*
957	* Construct the name.
958	*/
959	char szPath[RTPATH_MAX];
960	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
961	size_t cch = strlen(szPath);
962	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
963
964	/*
965	* Open it and resolve the symbol.
966	*/
967	#if defined(RT_OS_WINDOWS)
968	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
969	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
970	if (!hMod)
971	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: LoadLibraryEx(\"%s\",,) failed, rc=%d\n",
972	szPath, GetLastError());
973	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedMain"));
974	if (!pfn)
975	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\" (rc=%d)\n",
976	szPath, GetLastError());
977	return (PFNSUPTRUSTEDMAIN)pfn;
978
979	#else
980	/* the dlopen crowd */
981	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
982	if (!pvMod)
983	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: dlopen(\"%s\",) failed: %s\n",
984	szPath, dlerror());
985	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedMain"));
986	if (!pvSym)
987	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\"!\ndlerror: %s\n",
988	szPath, dlerror());
989	return (PFNSUPTRUSTEDMAIN)(uintptr_t)pvSym;
990	#endif
991	}
992
993
994	/**
995	* Secure main.
996	*
997	* This is used for the set-user-ID-on-execute binaries on unixy systems
998	* and when using the open-vboxdrv-via-root-service setup on Windows.
999	*
1000	* This function will perform the integrity checks of the VirtualBox
1001	* installation, open the support driver, open the root service (later),
1002	* and load the DLL corresponding to \a pszProgName and execute its main
1003	* function.
1004	*
1005	* @returns Return code appropriate for main().
1006	*
1007	* @param pszProgName The program name. This will be used to figure out which
1008	* DLL/SO/DYLIB to load and execute.
1009	* @param fFlags Flags.
1010	* @param argc The argument count.
1011	* @param argv The argument vector.
1012	* @param envp The environment vector.
1013	*/
1014	DECLHIDDEN(int) SUPR3HardenedMain(const char pszProgName, uint32_t fFlags, int argc, char argv, char *envp)
1015	{
1016	/*
1017	* Note! At this point there is no IPRT, so we will have to stick
1018	* to basic CRT functions that everyone agree upon.
1019	*/
1020	g_pszSupLibHardenedProgName = pszProgName;
1021	g_SupPreInitData.u32Magic = SUPPREINITDATA_MAGIC;
1022	g_SupPreInitData.Data.hDevice = NIL_RTFILE;
1023	g_SupPreInitData.u32EndMagic = SUPPREINITDATA_MAGIC;
1024
1025	#ifdef SUP_HARDENED_SUID
1026	# ifdef RT_OS_LINUX
1027	/*
1028	* On linux we have to make sure the path is initialized because we
1029	* might not be able to access /proc/self/exe after the seteuid call.
1030	*/
1031	supR3HardenedGetFullExePath();
1032
1033	# endif
1034
1035	/*
1036	* Grab any options from the environment.
1037	*/
1038	supR3GrabOptions();
1039
1040	/*
1041	* Check that we're root, if we aren't then the installation is butchered.
1042	*/
1043	g_uid = getuid();
1044	g_gid = getgid();
1045	if (geteuid() != 0 /* root */)
1046	supR3HardenedFatalMsg("SUPR3HardenedMain", kSupInitOp_RootCheck, VERR_PERMISSION_DENIED,
1047	"Effective UID is not root (euid=%d egid=%d uid=%d gid=%d)",
1048	geteuid(), getegid(), g_uid, g_gid);
1049	#endif
1050
1051	/*
1052	* Validate the installation.
1053	*/
1054	supR3HardenedVerifyAll(true /* fFatal /, false / fLeaveFilesOpen */, pszProgName);
1055
1056	/*
1057	* Open the vboxdrv device.
1058	*/
1059	if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV))
1060	supR3HardenedMainOpenDevice();
1061
1062	/*
1063	* Open the root service connection.
1064	*/
1065	//if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_SVC))
1066	//supR3HardenedMainOpenService(&g_SupPreInitData, true /* fFatal */);
1067
1068	#ifdef SUP_HARDENED_SUID
1069	/*
1070	* Grab additional capabilities / privileges.
1071	*/
1072	supR3HardenedMainGrabCapabilites();
1073
1074	/*
1075	* Drop any root privileges we might be holding (won't return on failure)
1076	*/
1077	supR3HardenedMainDropPrivileges();
1078	#endif
1079
1080	/*
1081	* Load the IPRT, hand the SUPLib part the open driver and
1082	* call RTR3Init.
1083	*/
1084	supR3HardenedMainInitRuntime(fFlags);
1085
1086	/*
1087	* Load the DLL/SO/DYLIB containing the actual program
1088	* and pass control to it.
1089	*/
1090	PFNSUPTRUSTEDMAIN pfnTrustedMain = supR3HardenedMainGetTrustedMain(pszProgName);
1091	return pfnTrustedMain(argc, argv, envp);
1092	}
1093

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source: vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp@ 37233

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