bsd-cygwin_util.c revision 124208 
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 1.11 2003/08/07 06:23:43 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#define is_winnt       (GetVersion() < 0x80000000)
42
43#define ntsec_on(c)	((c) && strstr((c),"ntsec") && !strstr((c),"nontsec"))
44#define ntsec_off(c)	((c) && strstr((c),"nontsec"))
45#define ntea_on(c)	((c) && strstr((c),"ntea") && !strstr((c),"nontea"))
46
47#if defined(open) && open == binary_open
48# undef open
49#endif
50#if defined(pipe) && open == binary_pipe
51# undef pipe
52#endif
53
54int
55binary_open(const char *filename, int flags, ...)
56{
57	va_list ap;
58	mode_t mode;
59
60	va_start(ap, flags);
61	mode = va_arg(ap, mode_t);
62	va_end(ap);
63	return (open(filename, flags | O_BINARY, mode));
64}
65
66int
67binary_pipe(int fd[2])
68{
69	int ret = pipe(fd);
70
71	if (!ret) {
72		setmode(fd[0], O_BINARY);
73		setmode(fd[1], O_BINARY);
74	}
75	return (ret);
76}
77
78#define HAS_CREATE_TOKEN 1
79#define HAS_NTSEC_BY_DEFAULT 2
80
81static int
82has_capability(int what)
83{
84	static int inited;
85	static int has_create_token;
86	static int has_ntsec_by_default;
87
88	/*
89	 * has_capability() basically calls uname() and checks if
90	 * specific capabilities of Cygwin can be evaluated from that.
91	 * This simplifies the calling functions which only have to ask
92	 * for a capability using has_capability() instead of having
93	 * to figure that out by themselves.
94	 */
95	if (!inited) {
96		struct utsname uts;
97		char *c;
98
99		if (!uname(&uts)) {
100			int major_high = 0, major_low = 0, minor = 0;
101			int api_major_version = 0, api_minor_version = 0;
102			char *c;
103
104			sscanf(uts.release, "%d.%d.%d", &major_high,
105			    &major_low, &minor);
106			if ((c = strchr(uts.release, '(')) != NULL) {
107				sscanf(c + 1, "%d.%d", &api_major_version,
108				    &api_minor_version);
109			}
110			if (major_high > 1 ||
111			    (major_high == 1 && (major_low > 3 ||
112			    (major_low == 3 && minor >= 2))))
113				has_create_token = 1;
114			if (api_major_version > 0 || api_minor_version >= 56)
115				has_ntsec_by_default = 1;
116			inited = 1;
117		}
118	}
119	switch (what) {
120	case HAS_CREATE_TOKEN:
121		return (has_create_token);
122	case HAS_NTSEC_BY_DEFAULT:
123		return (has_ntsec_by_default);
124	}
125	return (0);
126}
127
128int
129check_nt_auth(int pwd_authenticated, struct passwd *pw)
130{
131	/*
132	* The only authentication which is able to change the user
133	* context on NT systems is the password authentication. So
134	* we deny all requsts for changing the user context if another
135	* authentication method is used.
136	*
137	* This doesn't apply to Cygwin versions >= 1.3.2 anymore which
138	* uses the undocumented NtCreateToken() call to create a user
139	* token if the process has the appropriate privileges and if
140	* CYGWIN ntsec setting is on.
141	*/
142	static int has_create_token = -1;
143
144	if (pw == NULL)
145		return 0;
146	if (is_winnt) {
147		if (has_create_token < 0) {
148			char *cygwin = getenv("CYGWIN");
149
150			has_create_token = 0;
151			if (has_capability(HAS_CREATE_TOKEN) &&
152			    (ntsec_on(cygwin) ||
153			    (has_capability(HAS_NTSEC_BY_DEFAULT) &&
154			    !ntsec_off(cygwin))))
155				has_create_token = 1;
156		}
157		if (has_create_token < 1 &&
158		    !pwd_authenticated && geteuid() != pw->pw_uid)
159			return (0);
160	}
161	return (1);
162}
163
164int
165check_ntsec(const char *filename)
166{
167	char *cygwin;
168	int allow_ntea = 0, allow_ntsec = 0;
169	struct statfs fsstat;
170
171	/* Windows 95/98/ME don't support file system security at all. */
172	if (!is_winnt)
173		return (0);
174
175	/* Evaluate current CYGWIN settings. */
176	cygwin = getenv("CYGWIN");
177	allow_ntea = ntea_on(cygwin);
178	allow_ntsec = ntsec_on(cygwin) ||
179	    (has_capability(HAS_NTSEC_BY_DEFAULT) && !ntsec_off(cygwin));
180
181	/*
182	 * `ntea' is an emulation of POSIX attributes. It doesn't support
183	 * real file level security as ntsec on NTFS file systems does
184	 * but it supports FAT filesystems. `ntea' is minimum requirement
185	 * for security checks.
186	 */
187	if (allow_ntea)
188		return (1);
189
190	/*
191	 * Retrieve file system flags. In Cygwin, file system flags are
192	 * copied to f_type which has no meaning in Win32 itself.
193	 */
194	if (statfs(filename, &fsstat))
195		return (1);
196
197	/*
198	 * Only file systems supporting ACLs are able to set permissions.
199	 * `ntsec' is the setting in Cygwin which switches using of NTFS
200	 * ACLs to support POSIX permissions on files.
201	 */
202	if (fsstat.f_type & FS_PERSISTENT_ACLS)
203		return (allow_ntsec);
204
205	return (0);
206}
207
208void
209register_9x_service(void)
210{
211        HINSTANCE kerneldll;
212        DWORD (*RegisterServiceProcess)(DWORD, DWORD);
213
214	/* The service register mechanism in 9x/Me is pretty different from
215	 * NT/2K/XP.  In NT/2K/XP we're using a special service starter
216	 * application to register and control sshd as service.  This method
217	 * doesn't play nicely with 9x/Me.  For that reason we register here
218	 * as service when running under 9x/Me.  This function is only called
219	 * by the child sshd when it's going to daemonize.
220	 */
221	if (is_winnt)
222		return;
223	if (!(kerneldll = LoadLibrary("KERNEL32.DLL")))
224		return;
225	if (!(RegisterServiceProcess = (DWORD (*)(DWORD, DWORD))
226		GetProcAddress(kerneldll, "RegisterServiceProcess")))
227		return;
228	RegisterServiceProcess(0, 1);
229}
230
231#endif /* HAVE_CYGWIN */
232