openbsd-compat/bsd-cygwin_util.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * cygwin_util.c
  *
  * Copyright (c) 2000, 2001, Corinna Vinschen <vinschen@cygnus.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Created: Sat Sep 02 12:17:00 2000 cv
  *
  * This file contains functions for forcing opened file descriptors to
  * binary mode on Windows systems.
  */

 #include "includes.h"

 RCSID("$Id: bsd-cygwin_util.c,v 1.10 2003/05/18 14:13:39 djm Exp $");

 #ifdef HAVE_CYGWIN

 #include <fcntl.h>
 #include <stdlib.h>
 #include <sys/utsname.h>
 #include <sys/vfs.h>
 #include <windows.h>
 #define is_winnt       (GetVersion() < 0x80000000)

 #define ntsec_on(c)	((c) && strstr((c),"ntsec") && !strstr((c),"nontsec"))
 #define ntsec_off(c)	((c) && strstr((c),"nontsec"))
 #define ntea_on(c)	((c) && strstr((c),"ntea") && !strstr((c),"nontea"))

 #if defined(open) && open == binary_open
 # undef open
 #endif
 #if defined(pipe) && open == binary_pipe
 # undef pipe
 #endif

 int
 binary_open(const char *filename, int flags, ...)
 {
 	va_list ap;
 	mode_t mode;

 	va_start(ap, flags);
 	mode = va_arg(ap, mode_t);
 	va_end(ap);
 	return (open(filename, flags | O_BINARY, mode));
 }

 int
 binary_pipe(int fd[2])
 {
 	int ret = pipe(fd);

 	if (!ret) {
 		setmode(fd[0], O_BINARY);
 		setmode(fd[1], O_BINARY);
 	}
 	return (ret);
 }

 #define HAS_CREATE_TOKEN 1
 #define HAS_NTSEC_BY_DEFAULT 2

 static int
 has_capability(int what)
 {
 	static int inited;
 	static int has_create_token;
 	static int has_ntsec_by_default;

 	/*
 	 * has_capability() basically calls uname() and checks if
 	 * specific capabilities of Cygwin can be evaluated from that.
 	 * This simplifies the calling functions which only have to ask
 	 * for a capability using has_capability() instead of having
 	 * to figure that out by themselves.
 	 */
 	if (!inited) {
 		struct utsname uts;
 		char *c;

 		if (!uname(&uts)) {
 			int major_high = 0, major_low = 0, minor = 0;
 			int api_major_version = 0, api_minor_version = 0;
 			char *c;

 			sscanf(uts.release, "%d.%d.%d", &major_high,
 			    &major_low, &minor);
 			if ((c = strchr(uts.release, '(')) != NULL) {
 				sscanf(c + 1, "%d.%d", &api_major_version,
 				    &api_minor_version);
 			}
 			if (major_high > 1 ||
 			    (major_high == 1 && (major_low > 3 ||
 			    (major_low == 3 && minor >= 2))))
 				has_create_token = 1;
 			if (api_major_version > 0 || api_minor_version >= 56)
 				has_ntsec_by_default = 1;
 			inited = 1;
 		}
 	}
 	switch (what) {
 	case HAS_CREATE_TOKEN:
 		return (has_create_token);
 	case HAS_NTSEC_BY_DEFAULT:
 		return (has_ntsec_by_default);
 	}
 	return (0);
 }

 int
 check_nt_auth(int pwd_authenticated, struct passwd *pw)
 {
 	/*
 	* The only authentication which is able to change the user
 	* context on NT systems is the password authentication. So
 	* we deny all requsts for changing the user context if another
 	* authentication method is used.
 	*
 	* This doesn't apply to Cygwin versions >= 1.3.2 anymore which
 	* uses the undocumented NtCreateToken() call to create a user
 	* token if the process has the appropriate privileges and if
 	* CYGWIN ntsec setting is on.
 	*/
 	static int has_create_token = -1;

 	if (pw == NULL)
 		return 0;
 	if (is_winnt) {
 		if (has_create_token < 0) {
 			char *cygwin = getenv("CYGWIN");

 			has_create_token = 0;
 			if (has_capability(HAS_CREATE_TOKEN) &&
 			    (ntsec_on(cygwin) ||
 			    (has_capability(HAS_NTSEC_BY_DEFAULT) &&
 			    !ntsec_off(cygwin))))
 				has_create_token = 1;
 		}
 		if (has_create_token < 1 &&
 		    !pwd_authenticated && geteuid() != pw->pw_uid)
 			return (0);
 	}
 	return (1);
 }

 int
 check_ntsec(const char *filename)
 {
 	char *cygwin;
 	int allow_ntea = 0, allow_ntsec = 0;
 	struct statfs fsstat;

 	/* Windows 95/98/ME don't support file system security at all. */
 	if (!is_winnt)
 		return (0);

 	/* Evaluate current CYGWIN settings. */
 	cygwin = getenv("CYGWIN");
 	allow_ntea = ntea_on(cygwin);
 	allow_ntsec = ntsec_on(cygwin) ||
 	    (has_capability(HAS_NTSEC_BY_DEFAULT) && !ntsec_off(cygwin));

 	/*
 	 * `ntea' is an emulation of POSIX attributes. It doesn't support
 	 * real file level security as ntsec on NTFS file systems does
 	 * but it supports FAT filesystems. `ntea' is minimum requirement
 	 * for security checks.
 	 */
 	if (allow_ntea)
 		return (1);

 	/*
 	 * Retrieve file system flags. In Cygwin, file system flags are
 	 * copied to f_type which has no meaning in Win32 itself.
 	 */
 	if (statfs(filename, &fsstat))
 		return (1);

 	/*
 	 * Only file systems supporting ACLs are able to set permissions.
 	 * `ntsec' is the setting in Cygwin which switches using of NTFS
 	 * ACLs to support POSIX permissions on files.
 	 */
 	if (fsstat.f_type & FS_PERSISTENT_ACLS)
 		return (allow_ntsec);

 	return (0);
 }

 void
 register_9x_service(void)
 {
         HINSTANCE kerneldll;
         DWORD (*RegisterServiceProcess)(DWORD, DWORD);

 	/* The service register mechanism in 9x/Me is pretty different from
 	 * NT/2K/XP.  In NT/2K/XP we're using a special service starter
 	 * application to register and control sshd as service.  This method
 	 * doesn't play nicely with 9x/Me.  For that reason we register here
 	 * as service when running under 9x/Me.  This function is only called
 	 * by the child sshd when it's going to daemonize.
 	 */
 	if (is_winnt)
 		return;
 	if (!(kerneldll = LoadLibrary("KERNEL32.DLL")))
 		return;
 	if (!(RegisterServiceProcess = (DWORD (*)(DWORD, DWORD))
 		GetProcAddress(kerneldll, "RegisterServiceProcess")))
 		return;
 	RegisterServiceProcess(0, 1);
 }

 #endif /* HAVE_CYGWIN */
	/*
	* cygwin_util.c
	*
	* Copyright (c) 2000, 2001, Corinna Vinschen <vinschen@cygnus.com>
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* Created: Sat Sep 02 12:17:00 2000 cv
	*
	* This file contains functions for forcing opened file descriptors to
	* binary mode on Windows systems.
	*/

	#include "includes.h"

	RCSID("$Id: bsd-cygwin_util.c,v 1.10 2003/05/18 14:13:39 djm Exp $");

	#ifdef HAVE_CYGWIN

	#include <fcntl.h>
	#include <stdlib.h>
	#include <sys/utsname.h>
	#include <sys/vfs.h>
	#include <windows.h>
	#define is_winnt (GetVersion() < 0x80000000)

	#define ntsec_on(c) ((c) && strstr((c),"ntsec") && !strstr((c),"nontsec"))
	#define ntsec_off(c) ((c) && strstr((c),"nontsec"))
	#define ntea_on(c) ((c) && strstr((c),"ntea") && !strstr((c),"nontea"))

	#if defined(open) && open == binary_open
	# undef open
	#endif
	#if defined(pipe) && open == binary_pipe
	# undef pipe
	#endif

	int
	binary_open(const char *filename, int flags, ...)
	{
	va_list ap;
	mode_t mode;

	va_start(ap, flags);
	mode = va_arg(ap, mode_t);
	va_end(ap);
	return (open(filename, flags \| O_BINARY, mode));
	}

	int
	binary_pipe(int fd[2])
	{
	int ret = pipe(fd);

	if (!ret) {
	setmode(fd[0], O_BINARY);
	setmode(fd[1], O_BINARY);
	}
	return (ret);
	}

	#define HAS_CREATE_TOKEN 1
	#define HAS_NTSEC_BY_DEFAULT 2

	static int
	has_capability(int what)
	{
	static int inited;
	static int has_create_token;
	static int has_ntsec_by_default;

	/*
	* has_capability() basically calls uname() and checks if
	* specific capabilities of Cygwin can be evaluated from that.
	* This simplifies the calling functions which only have to ask
	* for a capability using has_capability() instead of having
	* to figure that out by themselves.
	*/
	if (!inited) {
	struct utsname uts;
	char *c;

	if (!uname(&uts)) {
	int major_high = 0, major_low = 0, minor = 0;
	int api_major_version = 0, api_minor_version = 0;
	char *c;

	sscanf(uts.release, "%d.%d.%d", &major_high,
	&major_low, &minor);
	if ((c = strchr(uts.release, '(')) != NULL) {
	sscanf(c + 1, "%d.%d", &api_major_version,
	&api_minor_version);
	}
	if (major_high > 1 \|\|
	(major_high == 1 && (major_low > 3 \|\|
	(major_low == 3 && minor >= 2))))
	has_create_token = 1;
	if (api_major_version > 0 \|\| api_minor_version >= 56)
	has_ntsec_by_default = 1;
	inited = 1;
	}
	}
	switch (what) {
	case HAS_CREATE_TOKEN:
	return (has_create_token);
	case HAS_NTSEC_BY_DEFAULT:
	return (has_ntsec_by_default);
	}
	return (0);
	}

	int
	check_nt_auth(int pwd_authenticated, struct passwd *pw)
	{
	/*
	* The only authentication which is able to change the user
	* context on NT systems is the password authentication. So
	* we deny all requsts for changing the user context if another
	* authentication method is used.
	*
	* This doesn't apply to Cygwin versions >= 1.3.2 anymore which
	* uses the undocumented NtCreateToken() call to create a user
	* token if the process has the appropriate privileges and if
	* CYGWIN ntsec setting is on.
	*/
	static int has_create_token = -1;

	if (pw == NULL)
	return 0;
	if (is_winnt) {
	if (has_create_token < 0) {
	char *cygwin = getenv("CYGWIN");

	has_create_token = 0;
	if (has_capability(HAS_CREATE_TOKEN) &&
	(ntsec_on(cygwin) \|\|
	(has_capability(HAS_NTSEC_BY_DEFAULT) &&
	!ntsec_off(cygwin))))
	has_create_token = 1;
	}
	if (has_create_token < 1 &&
	!pwd_authenticated && geteuid() != pw->pw_uid)
	return (0);
	}
	return (1);
	}

	int
	check_ntsec(const char *filename)
	{
	char *cygwin;
	int allow_ntea = 0, allow_ntsec = 0;
	struct statfs fsstat;

	/* Windows 95/98/ME don't support file system security at all. */
	if (!is_winnt)
	return (0);

	/* Evaluate current CYGWIN settings. */
	cygwin = getenv("CYGWIN");
	allow_ntea = ntea_on(cygwin);
	allow_ntsec = ntsec_on(cygwin) \|\|
	(has_capability(HAS_NTSEC_BY_DEFAULT) && !ntsec_off(cygwin));

	/*
	* `ntea' is an emulation of POSIX attributes. It doesn't support
	* real file level security as ntsec on NTFS file systems does
	* but it supports FAT filesystems. `ntea' is minimum requirement
	* for security checks.
	*/
	if (allow_ntea)
	return (1);

	/*
	* Retrieve file system flags. In Cygwin, file system flags are
	* copied to f_type which has no meaning in Win32 itself.
	*/
	if (statfs(filename, &fsstat))
	return (1);

	/*
	* Only file systems supporting ACLs are able to set permissions.
	* `ntsec' is the setting in Cygwin which switches using of NTFS
	* ACLs to support POSIX permissions on files.
	*/
	if (fsstat.f_type & FS_PERSISTENT_ACLS)
	return (allow_ntsec);

	return (0);
	}

	void
	register_9x_service(void)
	{
	HINSTANCE kerneldll;
	DWORD (*RegisterServiceProcess)(DWORD, DWORD);

	/* The service register mechanism in 9x/Me is pretty different from
	* NT/2K/XP. In NT/2K/XP we're using a special service starter
	* application to register and control sshd as service. This method
	* doesn't play nicely with 9x/Me. For that reason we register here
	* as service when running under 9x/Me. This function is only called
	* by the child sshd when it's going to daemonize.
	*/
	if (is_winnt)
	return;
	if (!(kerneldll = LoadLibrary("KERNEL32.DLL")))
	return;
	if (!(RegisterServiceProcess = (DWORD (*)(DWORD, DWORD))
	GetProcAddress(kerneldll, "RegisterServiceProcess")))
	return;
	RegisterServiceProcess(0, 1);
	}

	#endif /* HAVE_CYGWIN */