Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/ssh/sshd/../sshpty.c	Lines:	2	68	2.9 %
Date:	2017-11-07	Branches:	1	44	2.3 %


/* $OpenBSD: sshpty.c,v 1.31 2016/11/29 03:54:50 dtucker Exp $ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * Allocating a pseudo-terminal, and making it the controlling tty.
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <paths.h>
#include <pwd.h>
#include <stdarg.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <util.h>

#include "sshpty.h"
#include "log.h"

#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif

/*
 * Allocates and opens a pty.  Returns 0 if no pty could be allocated, or
 * nonzero if a pty was successfully allocated.  On success, open file
 * descriptors for the pty and tty sides and the name of the tty side are
 * returned (the buffer must be able to hold at least 64 characters).
 */

int
pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
{
	char buf[64];
	int i;

	i = openpty(ptyfd, ttyfd, buf, NULL, NULL);
	if (i < 0) {
		error("openpty: %.100s", strerror(errno));
		return 0;
	}
	strlcpy(namebuf, buf, namebuflen);	/* possible truncation */
	return 1;
}

/* Releases the tty.  Its ownership is returned to root, and permissions to 0666. */

void
pty_release(const char *tty)
{
	if (chown(tty, (uid_t) 0, (gid_t) 0) < 0)
		error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno));
	if (chmod(tty, (mode_t) 0666) < 0)
		error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno));
}

/* Makes the tty the process's controlling tty and sets it to sane modes. */

void
pty_make_controlling_tty(int *ttyfd, const char *tty)
{
	int fd;

	/* First disconnect from the old controlling tty. */
#ifdef TIOCNOTTY
	fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
	if (fd >= 0) {
		(void) ioctl(fd, TIOCNOTTY, NULL);
		close(fd);
	}
#endif /* TIOCNOTTY */
	if (setsid() < 0)
		error("setsid: %.100s", strerror(errno));

	/*
	 * Verify that we are successfully disconnected from the controlling
	 * tty.
	 */
	fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
	if (fd >= 0) {
		error("Failed to disconnect from controlling tty.");
		close(fd);
	}
	/* Make it our controlling tty. */
#ifdef TIOCSCTTY
	debug("Setting controlling tty using TIOCSCTTY.");
	if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
		error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
#endif /* TIOCSCTTY */
	fd = open(tty, O_RDWR);
	if (fd < 0)
		error("%.100s: %.100s", tty, strerror(errno));
	else
		close(fd);

	/* Verify that we now have a controlling tty. */
	fd = open(_PATH_TTY, O_WRONLY);
	if (fd < 0)
		error("open /dev/tty failed - could not set controlling tty: %.100s",
		    strerror(errno));
	else
		close(fd);
}

/* Changes the window size associated with the pty. */

void
pty_change_window_size(int ptyfd, u_int row, u_int col,
	u_int xpixel, u_int ypixel)
{
	struct winsize w;

	/* may truncate u_int -> u_short */
	w.ws_row = row;
	w.ws_col = col;
	w.ws_xpixel = xpixel;
	w.ws_ypixel = ypixel;
	(void) ioctl(ptyfd, TIOCSWINSZ, &w);
}

void
pty_setowner(struct passwd *pw, const char *tty)
{
	struct group *grp;
	gid_t gid;
	mode_t mode;
	struct stat st;

	/* Determine the group to make the owner of the tty. */
	grp = getgrnam("tty");
	gid = (grp != NULL) ? grp->gr_gid : pw->pw_gid;
	mode = (grp != NULL) ? 0620 : 0600;

	/*
	 * Change owner and mode of the tty as required.
	 * Warn but continue if filesystem is read-only and the uids match/
	 * tty is owned by root.
	 */
	if (stat(tty, &st))
		fatal("stat(%.100s) failed: %.100s", tty,
		    strerror(errno));

	if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
		if (chown(tty, pw->pw_uid, gid) < 0) {
			if (errno == EROFS &&
			    (st.st_uid == pw->pw_uid || st.st_uid == 0))
				debug("chown(%.100s, %u, %u) failed: %.100s",
				    tty, (u_int)pw->pw_uid, (u_int)gid,
				    strerror(errno));
			else
				fatal("chown(%.100s, %u, %u) failed: %.100s",
				    tty, (u_int)pw->pw_uid, (u_int)gid,
				    strerror(errno));
		}
	}

	if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
		if (chmod(tty, mode) < 0) {
			if (errno == EROFS &&
			    (st.st_mode & (S_IRGRP | S_IROTH)) == 0)
				debug("chmod(%.100s, 0%o) failed: %.100s",
				    tty, (u_int)mode, strerror(errno));
			else
				fatal("chmod(%.100s, 0%o) failed: %.100s",
				    tty, (u_int)mode, strerror(errno));
		}
	}
}

/* Disconnect from the controlling tty. */
void
disconnect_controlling_tty(void)
{
	int fd;

	if ((fd = open(_PATH_TTY, O_RDWR | O_NOCTTY)) >= 0) {
		(void) ioctl(fd, TIOCNOTTY, NULL);
		close(fd);
	}
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: sshpty.c,v 1.31 2016/11/29 03:54:50 dtucker Exp $ */
2			/*
3			* Author: Tatu Ylonen <ylo@cs.hut.fi>
4			* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5			* All rights reserved
6			* Allocating a pseudo-terminal, and making it the controlling tty.
7			*
8			* As far as I am concerned, the code I have written for this software
9			* can be used freely for any purpose. Any derived versions of this
10			* software must be clearly marked as such, and if the derived work is
11			* incompatible with the protocol description in the RFC file, it must be
12			* called by a name other than "ssh" or "Secure Shell".
13			*/
14
15			#include <sys/types.h>
16			#include <sys/ioctl.h>
17			#include <sys/stat.h>
18
19			#include <errno.h>
20			#include <fcntl.h>
21			#include <grp.h>
22			#include <paths.h>
23			#include <pwd.h>
24			#include <stdarg.h>
25			#include <string.h>
26			#include <termios.h>
27			#include <unistd.h>
28			#include <util.h>
29
30			#include "sshpty.h"
31			#include "log.h"
32
33			#ifndef O_NOCTTY
34			#define O_NOCTTY 0
35			#endif
36
37			/*
38			* Allocates and opens a pty. Returns 0 if no pty could be allocated, or
39			* nonzero if a pty was successfully allocated. On success, open file
40			* descriptors for the pty and tty sides and the name of the tty side are
41			* returned (the buffer must be able to hold at least 64 characters).
42			*/
43
44			int
45			pty_allocate(int ptyfd, int ttyfd, char *namebuf, size_t namebuflen)
46			{
47			char buf[64];
48			int i;
49
50			i = openpty(ptyfd, ttyfd, buf, NULL, NULL);
51			if (i < 0) {
52			error("openpty: %.100s", strerror(errno));
53			return 0;
54			}
55			strlcpy(namebuf, buf, namebuflen); /* possible truncation */
56			return 1;
57			}
58
59			/* Releases the tty. Its ownership is returned to root, and permissions to 0666. */
60
61			void
62			pty_release(const char *tty)
63			{
64			if (chown(tty, (uid_t) 0, (gid_t) 0) < 0)
65			error("chown %.100s 0 0 failed: %.100s", tty, strerror(errno));
66			if (chmod(tty, (mode_t) 0666) < 0)
67			error("chmod %.100s 0666 failed: %.100s", tty, strerror(errno));
68			}
69
70			/* Makes the tty the process's controlling tty and sets it to sane modes. */
71
72			void
73			pty_make_controlling_tty(int ttyfd, const char tty)
74			{
75			int fd;
76
77			/* First disconnect from the old controlling tty. */
78			#ifdef TIOCNOTTY
79			fd = open(_PATH_TTY, O_RDWR \| O_NOCTTY);
80			if (fd >= 0) {
81			(void) ioctl(fd, TIOCNOTTY, NULL);
82			close(fd);
83			}
84			#endif /* TIOCNOTTY */
85			if (setsid() < 0)
86			error("setsid: %.100s", strerror(errno));
87
88			/*
89			* Verify that we are successfully disconnected from the controlling
90			* tty.
91			*/
92			fd = open(_PATH_TTY, O_RDWR \| O_NOCTTY);
93			if (fd >= 0) {
94			error("Failed to disconnect from controlling tty.");
95			close(fd);
96			}
97			/* Make it our controlling tty. */
98			#ifdef TIOCSCTTY
99			debug("Setting controlling tty using TIOCSCTTY.");
100			if (ioctl(*ttyfd, TIOCSCTTY, NULL) < 0)
101			error("ioctl(TIOCSCTTY): %.100s", strerror(errno));
102			#endif /* TIOCSCTTY */
103			fd = open(tty, O_RDWR);
104			if (fd < 0)
105			error("%.100s: %.100s", tty, strerror(errno));
106			else
107			close(fd);
108
109			/* Verify that we now have a controlling tty. */
110			fd = open(_PATH_TTY, O_WRONLY);
111			if (fd < 0)
112			error("open /dev/tty failed - could not set controlling tty: %.100s",
113			strerror(errno));
114			else
115			close(fd);
116			}
117
118			/* Changes the window size associated with the pty. */
119
120			void
121			pty_change_window_size(int ptyfd, u_int row, u_int col,
122			u_int xpixel, u_int ypixel)
123			{
124			struct winsize w;
125
126			/* may truncate u_int -> u_short */
127			w.ws_row = row;
128			w.ws_col = col;
129			w.ws_xpixel = xpixel;
130			w.ws_ypixel = ypixel;
131			(void) ioctl(ptyfd, TIOCSWINSZ, &w);
132			}
133
134			void
135			pty_setowner(struct passwd pw, const char tty)
136			{
137			struct group *grp;
138			gid_t gid;
139			mode_t mode;
140			struct stat st;
141
142			/* Determine the group to make the owner of the tty. */
143			grp = getgrnam("tty");
144			gid = (grp != NULL) ? grp->gr_gid : pw->pw_gid;
145			mode = (grp != NULL) ? 0620 : 0600;
146
147			/*
148			* Change owner and mode of the tty as required.
149			* Warn but continue if filesystem is read-only and the uids match/
150			* tty is owned by root.
151			*/
152			if (stat(tty, &st))
153			fatal("stat(%.100s) failed: %.100s", tty,
154			strerror(errno));
155
156			if (st.st_uid != pw->pw_uid \|\| st.st_gid != gid) {
157			if (chown(tty, pw->pw_uid, gid) < 0) {
158			if (errno == EROFS &&
159			(st.st_uid == pw->pw_uid \|\| st.st_uid == 0))
160			debug("chown(%.100s, %u, %u) failed: %.100s",
161			tty, (u_int)pw->pw_uid, (u_int)gid,
162			strerror(errno));
163			else
164			fatal("chown(%.100s, %u, %u) failed: %.100s",
165			tty, (u_int)pw->pw_uid, (u_int)gid,
166			strerror(errno));
167			}
168			}
169
170			if ((st.st_mode & (S_IRWXU\|S_IRWXG\|S_IRWXO)) != mode) {
171			if (chmod(tty, mode) < 0) {
172			if (errno == EROFS &&
173			(st.st_mode & (S_IRGRP \| S_IROTH)) == 0)
174			debug("chmod(%.100s, 0%o) failed: %.100s",
175			tty, (u_int)mode, strerror(errno));
176			else
177			fatal("chmod(%.100s, 0%o) failed: %.100s",
178			tty, (u_int)mode, strerror(errno));
179			}
180			}
181			}
182
183			/* Disconnect from the controlling tty. */
184			void
185			disconnect_controlling_tty(void)
186			{
187			int fd;
188
189	✗✓	12	if ((fd = open(_PATH_TTY, O_RDWR \| O_NOCTTY)) >= 0) {
190			(void) ioctl(fd, TIOCNOTTY, NULL);
191			close(fd);
192			}
193		6	}