bsd-cygwin_util.c revision 146998 
1/*
2 * Copyright (c) 2000, 2001, Corinna Vinschen <vinschen@cygnus.com>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 *
24 * Created: Sat Sep 02 12:17:00 2000 cv
25 *
26 * This file contains functions for forcing opened file descriptors to
27 * binary mode on Windows systems.
28 */
29
30#include "includes.h"
31
32RCSID("$Id: bsd-cygwin_util.c,v 1.13 2004/08/30 10:42:08 dtucker Exp $");
33
34#ifdef HAVE_CYGWIN
35
36#include <fcntl.h>
37#include <stdlib.h>
38#include <sys/utsname.h>
39#include <sys/vfs.h>
40#include <windows.h>
41#include "xmalloc.h"
42#define is_winnt       (GetVersion() < 0x80000000)
43
44#define ntsec_on(c)	((c) && strstr((c),"ntsec") && !strstr((c),"nontsec"))
45#define ntsec_off(c)	((c) && strstr((c),"nontsec"))
46#define ntea_on(c)	((c) && strstr((c),"ntea") && !strstr((c),"nontea"))
47
48#if defined(open) && open == binary_open
49# undef open
50#endif
51#if defined(pipe) && open == binary_pipe
52# undef pipe
53#endif
54
55int
56binary_open(const char *filename, int flags, ...)
57{
58	va_list ap;
59	mode_t mode;
60
61	va_start(ap, flags);
62	mode = va_arg(ap, mode_t);
63	va_end(ap);
64	return (open(filename, flags | O_BINARY, mode));
65}
66
67int
68binary_pipe(int fd[2])
69{
70	int ret = pipe(fd);
71
72	if (!ret) {
73		setmode(fd[0], O_BINARY);
74		setmode(fd[1], O_BINARY);
75	}
76	return (ret);
77}
78
79#define HAS_CREATE_TOKEN 1
80#define HAS_NTSEC_BY_DEFAULT 2
81#define HAS_CREATE_TOKEN_WO_NTSEC 3
82
83static int
84has_capability(int what)
85{
86	static int inited;
87	static int has_create_token;
88	static int has_ntsec_by_default;
89	static int has_create_token_wo_ntsec;
90
91	/*
92	 * has_capability() basically calls uname() and checks if
93	 * specific capabilities of Cygwin can be evaluated from that.
94	 * This simplifies the calling functions which only have to ask
95	 * for a capability using has_capability() instead of having
96	 * to figure that out by themselves.
97	 */
98	if (!inited) {
99		struct utsname uts;
100
101		if (!uname(&uts)) {
102			int major_high = 0, major_low = 0, minor = 0;
103			int api_major_version = 0, api_minor_version = 0;
104			char *c;
105
106			sscanf(uts.release, "%d.%d.%d", &major_high,
107			    &major_low, &minor);
108			if ((c = strchr(uts.release, '(')) != NULL) {
109				sscanf(c + 1, "%d.%d", &api_major_version,
110				    &api_minor_version);
111			}
112			if (major_high > 1 ||
113			    (major_high == 1 && (major_low > 3 ||
114			    (major_low == 3 && minor >= 2))))
115				has_create_token = 1;
116			if (api_major_version > 0 || api_minor_version >= 56)
117				has_ntsec_by_default = 1;
118			if (major_high > 1 ||
119			    (major_high == 1 && major_low >= 5))
120				has_create_token_wo_ntsec = 1;
121			inited = 1;
122		}
123	}
124	switch (what) {
125	case HAS_CREATE_TOKEN:
126		return (has_create_token);
127	case HAS_NTSEC_BY_DEFAULT:
128		return (has_ntsec_by_default);
129	case HAS_CREATE_TOKEN_WO_NTSEC:
130		return (has_create_token_wo_ntsec);
131	}
132	return (0);
133}
134
135int
136check_nt_auth(int pwd_authenticated, struct passwd *pw)
137{
138	/*
139	* The only authentication which is able to change the user
140	* context on NT systems is the password authentication. So
141	* we deny all requsts for changing the user context if another
142	* authentication method is used.
143	*
144	* This doesn't apply to Cygwin versions >= 1.3.2 anymore which
145	* uses the undocumented NtCreateToken() call to create a user
146	* token if the process has the appropriate privileges and if
147	* CYGWIN ntsec setting is on.
148	*/
149	static int has_create_token = -1;
150
151	if (pw == NULL)
152		return 0;
153	if (is_winnt) {
154		if (has_create_token < 0) {
155			char *cygwin = getenv("CYGWIN");
156
157			has_create_token = 0;
158			if (has_capability(HAS_CREATE_TOKEN) &&
159			    (ntsec_on(cygwin) ||
160			    (has_capability(HAS_NTSEC_BY_DEFAULT) &&
161			     !ntsec_off(cygwin)) ||
162			     has_capability(HAS_CREATE_TOKEN_WO_NTSEC)))
163				has_create_token = 1;
164		}
165		if (has_create_token < 1 &&
166		    !pwd_authenticated && geteuid() != pw->pw_uid)
167			return (0);
168	}
169	return (1);
170}
171
172int
173check_ntsec(const char *filename)
174{
175	char *cygwin;
176	int allow_ntea = 0, allow_ntsec = 0;
177	struct statfs fsstat;
178
179	/* Windows 95/98/ME don't support file system security at all. */
180	if (!is_winnt)
181		return (0);
182
183	/* Evaluate current CYGWIN settings. */
184	cygwin = getenv("CYGWIN");
185	allow_ntea = ntea_on(cygwin);
186	allow_ntsec = ntsec_on(cygwin) ||
187	    (has_capability(HAS_NTSEC_BY_DEFAULT) && !ntsec_off(cygwin));
188
189	/*
190	 * `ntea' is an emulation of POSIX attributes. It doesn't support
191	 * real file level security as ntsec on NTFS file systems does
192	 * but it supports FAT filesystems. `ntea' is minimum requirement
193	 * for security checks.
194	 */
195	if (allow_ntea)
196		return (1);
197
198	/*
199	 * Retrieve file system flags. In Cygwin, file system flags are
200	 * copied to f_type which has no meaning in Win32 itself.
201	 */
202	if (statfs(filename, &fsstat))
203		return (1);
204
205	/*
206	 * Only file systems supporting ACLs are able to set permissions.
207	 * `ntsec' is the setting in Cygwin which switches using of NTFS
208	 * ACLs to support POSIX permissions on files.
209	 */
210	if (fsstat.f_type & FS_PERSISTENT_ACLS)
211		return (allow_ntsec);
212
213	return (0);
214}
215
216void
217register_9x_service(void)
218{
219        HINSTANCE kerneldll;
220        DWORD (*RegisterServiceProcess)(DWORD, DWORD);
221
222	/* The service register mechanism in 9x/Me is pretty different from
223	 * NT/2K/XP.  In NT/2K/XP we're using a special service starter
224	 * application to register and control sshd as service.  This method
225	 * doesn't play nicely with 9x/Me.  For that reason we register here
226	 * as service when running under 9x/Me.  This function is only called
227	 * by the child sshd when it's going to daemonize.
228	 */
229	if (is_winnt)
230		return;
231	if (!(kerneldll = LoadLibrary("KERNEL32.DLL")))
232		return;
233	if (!(RegisterServiceProcess = (DWORD (*)(DWORD, DWORD))
234		GetProcAddress(kerneldll, "RegisterServiceProcess")))
235		return;
236	RegisterServiceProcess(0, 1);
237}
238
239#define NL(x) x, (sizeof (x) - 1)
240#define WENV_SIZ (sizeof (wenv_arr) / sizeof (wenv_arr[0]))
241
242static struct wenv {
243	const char *name;
244	size_t namelen;
245} wenv_arr[] = {
246	{ NL("ALLUSERSPROFILE=") },
247	{ NL("COMMONPROGRAMFILES=") },
248	{ NL("COMPUTERNAME=") },
249	{ NL("COMSPEC=") },
250	{ NL("NUMBER_OF_PROCESSORS=") },
251	{ NL("OS=") },
252	{ NL("PATH=") },
253	{ NL("PATHEXT=") },
254	{ NL("PROCESSOR_ARCHITECTURE=") },
255	{ NL("PROCESSOR_IDENTIFIER=") },
256	{ NL("PROCESSOR_LEVEL=") },
257	{ NL("PROCESSOR_REVISION=") },
258	{ NL("PROGRAMFILES=") },
259	{ NL("SYSTEMDRIVE=") },
260	{ NL("SYSTEMROOT=") },
261	{ NL("TMP=") },
262	{ NL("TEMP=") },
263	{ NL("WINDIR=") },
264};
265
266char **
267fetch_windows_environment(void)
268{
269	char **e, **p;
270	int i, idx = 0;
271
272	p = xmalloc(WENV_SIZ * sizeof(char *));
273	for (e = environ; *e != NULL; ++e) {
274		for (i = 0; i < WENV_SIZ; ++i) {
275			if (!strncmp(*e, wenv_arr[i].name, wenv_arr[i].namelen))
276				p[idx++] = *e;
277		}
278	}
279	p[idx] = NULL;
280	return p;
281}
282
283void
284free_windows_environment(char **p)
285{
286	xfree(p);
287}
288
289#endif /* HAVE_CYGWIN */
290