SUPR3HardenedMain.cpp@ 25472

Last change on this file since 25472 was 25472, checked in by vboxsync, 15 years ago
FreeBSD: Use sysctl instead of procfs to retrieve executable path and arguments. Contributed by Bernhard Froehlich and Baptiste Daroussin
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 34.3 KB

Line
1	/* $Id: SUPR3HardenedMain.cpp 25472 2009-12-17 21:48:33Z 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_FREEBSD)
70	# include <sys/param.h>
71	# include <sys/sysctl.h>
72	# elif defined(RT_OS_SOLARIS)
73	# include <priv.h>
74	# endif
75	# include <pwd.h>
76	# ifdef RT_OS_DARWIN
77	# include <mach-o/dyld.h>
78	# endif
79
80	#endif
81
82	#include <VBox/sup.h>
83	#include <VBox/err.h>
84	#include <iprt/string.h>
85	#include <iprt/param.h>
86
87	#include "SUPLibInternal.h"
88
89
90	/*******************************************************************************
91	* Defined Constants And Macros *
92	*******************************************************************************/
93	/** @def SUP_HARDENED_SUID
94	* Whether we're employing set-user-ID-on-execute in the hardening.
95	*/
96	#if !defined(RT_OS_OS2) && !defined(RT_OS_WINDOWS) && !defined(RT_OS_L4)
97	# define SUP_HARDENED_SUID
98	#else
99	# undef SUP_HARDENED_SUID
100	#endif
101
102	/** @def SUP_HARDENED_SYM
103	* Decorate a symbol that's resolved dynamically.
104	*/
105	#ifdef RT_OS_OS2
106	# define SUP_HARDENED_SYM(sym) "_" sym
107	#else
108	# define SUP_HARDENED_SYM(sym) sym
109	#endif
110
111
112	/*******************************************************************************
113	* Structures and Typedefs *
114	*******************************************************************************/
115	/** @see RTR3InitEx */
116	typedef DECLCALLBACK(int) FNRTR3INITEX(uint32_t iVersion, const char *pszProgramPath, bool fInitSUPLib);
117	typedef FNRTR3INITEX *PFNRTR3INITEX;
118
119
120	/*******************************************************************************
121	* Global Variables *
122	*******************************************************************************/
123	/** The pre-init data we pass on to SUPR3 (residing in VBoxRT). */
124	static SUPPREINITDATA g_SupPreInitData;
125	/** The progam executable path. */
126	static char g_szSupLibHardenedExePath[RTPATH_MAX];
127	/** The program directory path. */
128	static char g_szSupLibHardenedDirPath[RTPATH_MAX];
129
130	/** The program name. */
131	static const char *g_pszSupLibHardenedProgName;
132
133	#ifdef SUP_HARDENED_SUID
134	/** The real UID at startup. */
135	static uid_t g_uid;
136	/** The real GID at startup. */
137	static gid_t g_gid;
138	# ifdef RT_OS_LINUX
139	static uint32_t g_uCaps;
140	# endif
141	#endif
142
143	/*******************************************************************************
144	* Internal Functions *
145	*******************************************************************************/
146	#ifdef SUP_HARDENED_SUID
147	static void supR3HardenedMainDropPrivileges(void);
148	#endif
149	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName);
150
151
152	/**
153	* @copydoc RTPathStripFilename.
154	*/
155	static void suplibHardenedPathStripFilename(char *pszPath)
156	{
157	char *psz = pszPath;
158	char *pszLastSep = pszPath;
159
160	for (;; psz++)
161	{
162	switch (*psz)
163	{
164	/* handle separators. */
165	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
166	case ':':
167	pszLastSep = psz + 1;
168	break;
169
170	case '\\':
171	#endif
172	case '/':
173	pszLastSep = psz;
174	break;
175
176	/* the end */
177	case '\0':
178	if (pszLastSep == pszPath)
179	*pszLastSep++ = '.';
180	*pszLastSep = '\0';
181	return;
182	}
183	}
184	/* will never get here */
185	}
186
187
188	/**
189	* @copydoc RTPathFilename
190	*/
191	DECLHIDDEN(char ) supR3HardenedPathFilename(const char pszPath)
192	{
193	const char *psz = pszPath;
194	const char *pszLastComp = pszPath;
195
196	for (;; psz++)
197	{
198	switch (*psz)
199	{
200	/* handle separators. */
201	#if defined(RT_OS_WINDOWS) \|\| defined(RT_OS_OS2)
202	case ':':
203	pszLastComp = psz + 1;
204	break;
205
206	case '\\':
207	#endif
208	case '/':
209	pszLastComp = psz + 1;
210	break;
211
212	/* the end */
213	case '\0':
214	if (*pszLastComp)
215	return (char )(void )pszLastComp;
216	return NULL;
217	}
218	}
219
220	/* will never get here */
221	return NULL;
222	}
223
224
225	/**
226	* @copydoc RTPathAppPrivateNoArch
227	*/
228	DECLHIDDEN(int) supR3HardenedPathAppPrivateNoArch(char *pszPath, size_t cchPath)
229	{
230	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE)
231	const char *pszSrcPath = RTPATH_APP_PRIVATE;
232	size_t cchPathPrivateNoArch = strlen(pszSrcPath);
233	if (cchPathPrivateNoArch >= cchPath)
234	supR3HardenedFatal("supR3HardenedPathAppPrivateNoArch: Buffer overflow, %lu >= %lu\n",
235	(unsigned long)cchPathPrivateNoArch, (unsigned long)cchPath);
236	memcpy(pszPath, pszSrcPath, cchPathPrivateNoArch + 1);
237	return VINF_SUCCESS;
238
239	#else
240	return supR3HardenedPathExecDir(pszPath, cchPath);
241	#endif
242	}
243
244
245	/**
246	* @copydoc RTPathAppPrivateArch
247	*/
248	DECLHIDDEN(int) supR3HardenedPathAppPrivateArch(char *pszPath, size_t cchPath)
249	{
250	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH)
251	const char *pszSrcPath = RTPATH_APP_PRIVATE_ARCH;
252	size_t cchPathPrivateArch = strlen(pszSrcPath);
253	if (cchPathPrivateArch >= cchPath)
254	supR3HardenedFatal("supR3HardenedPathAppPrivateArch: Buffer overflow, %lu >= %lu\n",
255	(unsigned long)cchPathPrivateArch, (unsigned long)cchPath);
256	memcpy(pszPath, pszSrcPath, cchPathPrivateArch + 1);
257	return VINF_SUCCESS;
258
259	#else
260	return supR3HardenedPathExecDir(pszPath, cchPath);
261	#endif
262	}
263
264
265	/**
266	* @copydoc RTPathSharedLibs
267	*/
268	DECLHIDDEN(int) supR3HardenedPathSharedLibs(char *pszPath, size_t cchPath)
269	{
270	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_SHARED_LIBS)
271	const char *pszSrcPath = RTPATH_SHARED_LIBS;
272	size_t cchPathSharedLibs = strlen(pszSrcPath);
273	if (cchPathSharedLibs >= cchPath)
274	supR3HardenedFatal("supR3HardenedPathSharedLibs: Buffer overflow, %lu >= %lu\n",
275	(unsigned long)cchPathSharedLibs, (unsigned long)cchPath);
276	memcpy(pszPath, pszSrcPath, cchPathSharedLibs + 1);
277	return VINF_SUCCESS;
278
279	#else
280	return supR3HardenedPathExecDir(pszPath, cchPath);
281	#endif
282	}
283
284
285	/**
286	* @copydoc RTPathAppDocs
287	*/
288	DECLHIDDEN(int) supR3HardenedPathAppDocs(char *pszPath, size_t cchPath)
289	{
290	#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_DOCS)
291	const char *pszSrcPath = RTPATH_APP_DOCS;
292	size_t cchPathAppDocs = strlen(pszSrcPath);
293	if (cchPathAppDocs >= cchPath)
294	supR3HardenedFatal("supR3HardenedPathAppDocs: Buffer overflow, %lu >= %lu\n",
295	(unsigned long)cchPathAppDocs, (unsigned long)cchPath);
296	memcpy(pszPath, pszSrcPath, cchPathAppDocs + 1);
297	return VINF_SUCCESS;
298
299	#else
300	return supR3HardenedPathExecDir(pszPath, cchPath);
301	#endif
302	}
303
304
305	/**
306	* Returns the full path to the executable.
307	*
308	* @returns IPRT status code.
309	* @param pszPath Where to store it.
310	* @param cchPath How big that buffer is.
311	*/
312	static void supR3HardenedGetFullExePath(void)
313	{
314	/*
315	* Get the program filename.
316	*
317	* Most UNIXes have no API for obtaining the executable path, but provides a symbolic
318	* link in the proc file system that tells who was exec'ed. The bad thing about this
319	* is that we have to use readlink, one of the weirder UNIX APIs.
320	*
321	* Darwin, OS/2 and Windows all have proper APIs for getting the program file name.
322	*/
323	#if defined(RT_OS_LINUX) \|\| defined(RT_OS_FREEBSD) \|\| defined(RT_OS_SOLARIS)
324	# ifdef RT_OS_LINUX
325	int cchLink = readlink("/proc/self/exe", &g_szSupLibHardenedExePath[0], sizeof(g_szSupLibHardenedExePath) - 1);
326	# 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	# else /* RT_OS_FREEBSD: */
331	int aiName[4];
332	size_t cbPath;
333
334	aiName[0] = CTL_KERN;
335	aiName[1] = KERN_PROC;
336	aiName[2] = KERN_PROC_PATHNAME;
337	aiName[3] = getpid();
338
339	cbPath = sizeof(g_szSupLibHardenedExePath) - 1;
340	if(sysctl(aiName, RT_ELEMENTS(aiName), g_szSupLibHardenedExePath, &cbPath, NULL, 0) < 0)
341	supR3HardenedFatal("supR3HardenedExecDir: sysctl failed\n");
342
343	int cchLink = strlen(g_szSupLibHardenedExePath);
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 invovled 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, /keep=/1, 0, 0, 0);
636	# else
637	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
638	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
639	memset(hdr, 0, sizeof(*hdr));
640	hdr->version = _LINUX_CAPABILITY_VERSION;
641	memset(cap, 0, sizeof(*cap));
642	cap->effective = g_uCaps;
643	cap->permitted = g_uCaps;
644	if (!capset(hdr, cap))
645	prctl(PR_SET_KEEPCAPS, /keep=/1, 0, 0, 0);
646	# endif /* !USE_LIB_PCAP */
647	}
648
649	# elif defined(RT_OS_SOLARIS)
650	/*
651	* Add net_icmpaccess privilege to permitted, effective and inheritable privileges
652	* before dropping root privileges.
653	*/
654	priv_set_t *pPrivSet = priv_str_to_set("basic", ",", NULL);
655	if (pPrivSet)
656	{
657	priv_addset(pPrivSet, PRIV_NET_ICMPACCESS);
658	int rc = setppriv(PRIV_SET, PRIV_INHERITABLE, pPrivSet);
659	if (!rc)
660	{
661	rc = setppriv(PRIV_SET, PRIV_PERMITTED, pPrivSet);
662	if (!rc)
663	{
664	rc = setppriv(PRIV_SET, PRIV_EFFECTIVE, pPrivSet);
665	if (rc)
666	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set effectives privilege set.\n");
667	}
668	else
669	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set permitted privilege set.\n");
670	}
671	else
672	supR3HardenedError(rc, false, "SUPR3HardenedMain: failed to set inheritable privilege set.\n");
673
674	priv_freeset(pPrivSet);
675	}
676	else
677	supR3HardenedError(-1, false, "SUPR3HardenedMain: failed to get basic privilege set.\n");
678
679	# endif
680	}
681
682	/*
683	* Look at the environment for some special options.
684	*/
685	static void supR3GrabOptions(void)
686	{
687	const char *pszOpt;
688
689	# ifdef RT_OS_LINUX
690	g_uCaps = 0;
691
692	/*
693	* Do _not_ perform any capability-related system calls for root processes
694	* (leaving g_uCaps at 0).
695	* (Hint: getuid gets the real user id, not the effective.)
696	*/
697	if (getuid() != 0)
698	{
699	/*
700	* CAP_NET_RAW.
701	* Default: enabled.
702	* Can be disabled with 'export VBOX_HARD_CAP_NET_RAW=0'.
703	*/
704	pszOpt = getenv("VBOX_HARD_CAP_NET_RAW");
705	if ( !pszOpt
706	\|\| memcmp(pszOpt, "0", sizeof("0")) != 0)
707	g_uCaps = CAP_TO_MASK(CAP_NET_RAW);
708
709	/*
710	* CAP_NET_BIND_SERVICE.
711	* Default: disabled.
712	* Can be enabled with 'export VBOX_HARD_CAP_NET_BIND_SERVICE=1'.
713	*/
714	pszOpt = getenv("VBOX_HARD_CAP_NET_BIND_SERVICE");
715	if ( pszOpt
716	&& memcmp(pszOpt, "0", sizeof("0")) != 0)
717	g_uCaps \|= CAP_TO_MASK(CAP_NET_BIND_SERVICE);
718	}
719	# endif
720	}
721
722	/**
723	* Drop any root privileges we might be holding.
724	*/
725	static void supR3HardenedMainDropPrivileges(void)
726	{
727	/*
728	* Try use setre[ug]id since this will clear the save uid/gid and thus
729	* leave fewer traces behind that libs like GTK+ may pick up.
730	*/
731	uid_t euid, ruid, suid;
732	gid_t egid, rgid, sgid;
733	# if defined(RT_OS_DARWIN)
734	/* The really great thing here is that setreuid isn't available on
735	OS X 10.4, libc emulates it. While 10.4 have a sligtly different and
736	non-standard setuid implementation compared to 10.5, the following
737	works the same way with both version since we're super user (10.5 req).
738	The following will set all three variants of the group and user IDs. */
739	setgid(g_gid);
740	setuid(g_uid);
741	euid = geteuid();
742	ruid = suid = getuid();
743	egid = getegid();
744	rgid = sgid = getgid();
745
746	# elif defined(RT_OS_SOLARIS)
747	/* Solaris doesn't have setresuid, but the setreuid interface is BSD
748	compatible and will set the saved uid to euid when we pass it a ruid
749	that isn't -1 (which we do). */
750	setregid(g_gid, g_gid);
751	setreuid(g_uid, g_uid);
752	euid = geteuid();
753	ruid = suid = getuid();
754	egid = getegid();
755	rgid = sgid = getgid();
756
757	# else
758	/* This is the preferred one, full control no questions about semantics.
759	PORTME: If this isn't work, try join one of two other gangs above. */
760	setresgid(g_gid, g_gid, g_gid);
761	setresuid(g_uid, g_uid, g_uid);
762	if (getresuid(&ruid, &euid, &suid) != 0)
763	{
764	euid = geteuid();
765	ruid = suid = getuid();
766	}
767	if (getresgid(&rgid, &egid, &sgid) != 0)
768	{
769	egid = getegid();
770	rgid = sgid = getgid();
771	}
772	# endif
773
774
775	/* Check that it worked out all right. */
776	if ( euid != g_uid
777	\|\| ruid != g_uid
778	\|\| suid != g_uid
779	\|\| egid != g_gid
780	\|\| rgid != g_gid
781	\|\| sgid != g_gid)
782	supR3HardenedFatal("SUPR3HardenedMain: failed to drop root privileges!"
783	" (euid=%d ruid=%d suid=%d egid=%d rgid=%d sgid=%d; wanted uid=%d and gid=%d)\n",
784	euid, ruid, suid, egid, rgid, sgid, g_uid, g_gid);
785
786	# if RT_OS_LINUX
787	/*
788	* Re-enable the cap_net_raw capability which was disabled during setresuid.
789	*/
790	if (g_uCaps != 0)
791	{
792	# ifdef USE_LIB_PCAP
793	/** @todo Warn if that does not work? */
794	/* XXX cap_net_bind_service */
795	cap_set_proc(cap_from_text("cap_net_raw+ep"));
796	# else
797	cap_user_header_t hdr = (cap_user_header_t)alloca(sizeof(*hdr));
798	cap_user_data_t cap = (cap_user_data_t)alloca(sizeof(*cap));
799	memset(hdr, 0, sizeof(*hdr));
800	hdr->version = _LINUX_CAPABILITY_VERSION;
801	memset(cap, 0, sizeof(*cap));
802	cap->effective = g_uCaps;
803	cap->permitted = g_uCaps;
804	/** @todo Warn if that does not work? */
805	capset(hdr, cap);
806	# endif /* !USE_LIB_PCAP */
807	}
808	# endif
809	}
810
811	#endif /* SUP_HARDENED_SUID */
812
813	/**
814	* Loads the VBoxRT DLL/SO/DYLIB, hands it the open driver,
815	* and calls RTR3Init.
816	*
817	* @param fFlags The SUPR3HardenedMain fFlags argument, passed to supR3PreInit.
818	*
819	* @remarks VBoxRT contains both IPRT and SUPR3.
820	* @remarks This function will not return on failure.
821	*/
822	static void supR3HardenedMainInitRuntime(uint32_t fFlags)
823	{
824	/*
825	* Construct the name.
826	*/
827	char szPath[RTPATH_MAX];
828	supR3HardenedPathSharedLibs(szPath, sizeof(szPath) - sizeof("/VBoxRT" SUPLIB_DLL_SUFF));
829	strcat(szPath, "/VBoxRT" SUPLIB_DLL_SUFF);
830
831	/*
832	* Open it and resolve the symbols.
833	*/
834	#if defined(RT_OS_WINDOWS)
835	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
836	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
837	if (!hMod)
838	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
839	"LoadLibraryEx(\"%s\",,) failed (rc=%d)",
840	szPath, GetLastError());
841	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)GetProcAddress(hMod, SUP_HARDENED_SYM("RTR3InitEx"));
842	if (!pfnRTInitEx)
843	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
844	"Entrypoint \"RTR3InitEx\" not found in \"%s\" (rc=%d)",
845	szPath, GetLastError());
846
847	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)GetProcAddress(hMod, SUP_HARDENED_SYM("supR3PreInit"));
848	if (!pfnSUPPreInit)
849	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
850	"Entrypoint \"supR3PreInit\" not found in \"%s\" (rc=%d)",
851	szPath, GetLastError());
852
853	#else
854	/* the dlopen crowd */
855	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
856	if (!pvMod)
857	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_MODULE_NOT_FOUND,
858	"dlopen(\"%s\",) failed: %s",
859	szPath, dlerror());
860	PFNRTR3INITEX pfnRTInitEx = (PFNRTR3INITEX)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("RTR3InitEx"));
861	if (!pfnRTInitEx)
862	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
863	"Entrypoint \"RTR3InitEx\" not found in \"%s\"!\ndlerror: %s",
864	szPath, dlerror());
865	PFNSUPR3PREINIT pfnSUPPreInit = (PFNSUPR3PREINIT)(uintptr_t)dlsym(pvMod, SUP_HARDENED_SYM("supR3PreInit"));
866	if (!pfnSUPPreInit)
867	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, VERR_SYMBOL_NOT_FOUND,
868	"Entrypoint \"supR3PreInit\" not found in \"%s\"!\ndlerror: %s",
869	szPath, dlerror());
870	#endif
871
872	/*
873	* Make the calls.
874	*/
875	supR3HardenedGetPreInitData(&g_SupPreInitData);
876	int rc = pfnSUPPreInit(&g_SupPreInitData, fFlags);
877	if (RT_FAILURE(rc))
878	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
879	"supR3PreInit failed with rc=%d", rc);
880	const char *pszExePath = NULL;
881	#ifdef RT_OS_LINUX
882	if (!supR3HardenedMainIsProcSelfExeAccssible())
883	pszExePath = g_szSupLibHardenedExePath;
884	#endif
885	rc = pfnRTInitEx(0, pszExePath, !(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV));
886	if (RT_FAILURE(rc))
887	supR3HardenedFatalMsg("supR3HardenedMainInitRuntime", kSupInitOp_IPRT, rc,
888	"RTR3Init failed with rc=%d", rc);
889	}
890
891
892	/**
893	* Loads the DLL/SO/DYLIB containing the actual program and
894	* resolves the TrustedError symbol.
895	*
896	* This is very similar to supR3HardenedMainGetTrustedMain().
897	*
898	* @returns Pointer to the trusted error symbol if it is exported, NULL
899	* and no error messages otherwise.
900	* @param pszProgName The program name.
901	*/
902	static PFNSUPTRUSTEDERROR supR3HardenedMainGetTrustedError(const char *pszProgName)
903	{
904	/*
905	* Construct the name.
906	*/
907	char szPath[RTPATH_MAX];
908	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
909	size_t cch = strlen(szPath);
910	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
911
912	/*
913	* Open it and resolve the symbol.
914	*/
915	#if defined(RT_OS_WINDOWS)
916	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
917	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
918	if (!hMod)
919	return NULL;
920	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedError"));
921	if (!pfn)
922	return NULL;
923	return (PFNSUPTRUSTEDERROR)pfn;
924
925	#else
926	/* the dlopen crowd */
927	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
928	if (!pvMod)
929	return NULL;
930	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedError"));
931	if (!pvSym)
932	return NULL;
933	return (PFNSUPTRUSTEDERROR)(uintptr_t)pvSym;
934	#endif
935	}
936
937
938	/**
939	* Loads the DLL/SO/DYLIB containing the actual program and
940	* resolves the TrustedMain symbol.
941	*
942	* @returns Pointer to the trusted main of the actual program.
943	* @param pszProgName The program name.
944	* @remarks This function will not return on failure.
945	*/
946	static PFNSUPTRUSTEDMAIN supR3HardenedMainGetTrustedMain(const char *pszProgName)
947	{
948	/*
949	* Construct the name.
950	*/
951	char szPath[RTPATH_MAX];
952	supR3HardenedPathAppPrivateArch(szPath, sizeof(szPath) - 10);
953	size_t cch = strlen(szPath);
954	supR3HardenedStrPrintf(&szPath[cch], sizeof(szPath) - cch, "/%s%s", pszProgName, SUPLIB_DLL_SUFF);
955
956	/*
957	* Open it and resolve the symbol.
958	*/
959	#if defined(RT_OS_WINDOWS)
960	/** @todo consider using LOAD_WITH_ALTERED_SEARCH_PATH here! */
961	HMODULE hMod = LoadLibraryEx(szPath, NULL /hFile/, 0 /* dwFlags */);
962	if (!hMod)
963	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: LoadLibraryEx(\"%s\",,) failed, rc=%d\n",
964	szPath, GetLastError());
965	FARPROC pfn = GetProcAddress(hMod, SUP_HARDENED_SYM("TrustedMain"));
966	if (!pfn)
967	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\" (rc=%d)\n",
968	szPath, GetLastError());
969	return (PFNSUPTRUSTEDMAIN)pfn;
970
971	#else
972	/* the dlopen crowd */
973	void *pvMod = dlopen(szPath, RTLD_NOW \| RTLD_GLOBAL);
974	if (!pvMod)
975	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: dlopen(\"%s\",) failed: %s\n",
976	szPath, dlerror());
977	void *pvSym = dlsym(pvMod, SUP_HARDENED_SYM("TrustedMain"));
978	if (!pvSym)
979	supR3HardenedFatal("supR3HardenedMainGetTrustedMain: Entrypoint \"TrustedMain\" not found in \"%s\"!\ndlerror: %s\n",
980	szPath, dlerror());
981	return (PFNSUPTRUSTEDMAIN)(uintptr_t)pvSym;
982	#endif
983	}
984
985
986	/**
987	* Secure main.
988	*
989	* This is used for the set-user-ID-on-execute binaries on unixy systems
990	* and when using the open-vboxdrv-via-root-service setup on Windows.
991	*
992	* This function will perform the integrity checks of the VirtualBox
993	* installation, open the support driver, open the root service (later),
994	* and load the DLL corresponding to \a pszProgName and execute its main
995	* function.
996	*
997	* @returns Return code appropriate for main().
998	*
999	* @param pszProgName The program name. This will be used to figure out which
1000	* DLL/SO/DYLIB to load and execute.
1001	* @param fFlags Flags.
1002	* @param argc The argument count.
1003	* @param argv The argument vector.
1004	* @param envp The environment vector.
1005	*/
1006	DECLHIDDEN(int) SUPR3HardenedMain(const char pszProgName, uint32_t fFlags, int argc, char argv, char *envp)
1007	{
1008	/*
1009	* Note! At this point there is no IPRT, so we will have to stick
1010	* to basic CRT functions that everyone agree upon.
1011	*/
1012	g_pszSupLibHardenedProgName = pszProgName;
1013	g_SupPreInitData.u32Magic = SUPPREINITDATA_MAGIC;
1014	g_SupPreInitData.Data.hDevice = NIL_RTFILE;
1015	g_SupPreInitData.u32EndMagic = SUPPREINITDATA_MAGIC;
1016
1017	#ifdef SUP_HARDENED_SUID
1018	# ifdef RT_OS_LINUX
1019	/*
1020	* On linux we have to make sure the path is initialized because we
1021	* might not be able to access /proc/self/exe after the seteuid call.
1022	*/
1023	supR3HardenedGetFullExePath();
1024
1025	# endif
1026
1027	/*
1028	* Grab any options from the environment.
1029	*/
1030	supR3GrabOptions();
1031
1032	/*
1033	* Check that we're root, if we aren't then the installation is butchered.
1034	*/
1035	g_uid = getuid();
1036	g_gid = getgid();
1037	if (geteuid() != 0 /* root */)
1038	supR3HardenedFatalMsg("SUPR3HardenedMain", kSupInitOp_RootCheck, VERR_PERMISSION_DENIED,
1039	"Effective UID is not root (euid=%d egid=%d uid=%d gid=%d)",
1040	geteuid(), getegid(), g_uid, g_gid);
1041	#endif
1042
1043	/*
1044	* Validate the installation.
1045	*/
1046	supR3HardenedVerifyAll(true /* fFatal /, false / fLeaveFilesOpen */, pszProgName);
1047
1048	/*
1049	* Open the vboxdrv device.
1050	*/
1051	if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_DEV))
1052	supR3HardenedMainOpenDevice();
1053
1054	/*
1055	* Open the root service connection.
1056	*/
1057	//if (!(fFlags & SUPSECMAIN_FLAGS_DONT_OPEN_SVC))
1058	//supR3HardenedMainOpenService(&g_SupPreInitData, true /* fFatal */);
1059
1060	#ifdef SUP_HARDENED_SUID
1061	/*
1062	* Grab additional capabilities / privileges.
1063	*/
1064	supR3HardenedMainGrabCapabilites();
1065
1066	/*
1067	* Drop any root privileges we might be holding (won't return on failure)
1068	*/
1069	supR3HardenedMainDropPrivileges();
1070	#endif
1071
1072	/*
1073	* Load the IPRT, hand the SUPLib part the open driver and
1074	* call RTR3Init.
1075	*/
1076	supR3HardenedMainInitRuntime(fFlags);
1077
1078	/*
1079	* Load the DLL/SO/DYLIB containing the actual program
1080	* and pass control to it.
1081	*/
1082	PFNSUPTRUSTEDMAIN pfnTrustedMain = supR3HardenedMainGetTrustedMain(pszProgName);
1083	return pfnTrustedMain(argc, argv, envp);
1084	}
1085
1086

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source: vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp@ 25472

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