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linux-next/include/linux/tty.h
Eric W. Biederman 98a27ba485 tty: introduce no_tty and use it in selinux 
While researching the tty layer pid leaks I found a weird case in selinux when
we drop a controlling tty because of inadequate permissions we don't do the
normal hangup processing.  Which is a problem if it happens the session leader
has exec'd something that can no longer access the tty.

We already have code in the kernel to handle this case in the form of the
TIOCNOTTY ioctl.  So this patch factors out a helper function that is the
essence of that ioctl and calls it from the selinux code.

This removes the inconsistency in handling dropping of a controlling tty and
who knows it might even make some part of user space happy because it received
a SIGHUP it was expecting.

In addition since this removes the last user of proc_set_tty outside of
tty_io.c proc_set_tty is made static and removed from tty.h

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:04 -07:00

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#ifndef _LINUX_TTY_H
#define _LINUX_TTY_H
/*
* 'tty.h' defines some structures used by tty_io.c and some defines.
*/
#ifdef __KERNEL__
#include <linux/fs.h>
#include <linux/major.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/tty_driver.h>
#include <linux/tty_ldisc.h>
#include <linux/mutex.h>
#include <asm/system.h>
/*
* (Note: the *_driver.minor_start values 1, 64, 128, 192 are
* hardcoded at present.)
*/
#define NR_PTYS CONFIG_LEGACY_PTY_COUNT /* Number of legacy ptys */
#define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
#define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
#define NR_LDISCS 17
/* line disciplines */
#define N_TTY 0
#define N_SLIP 1
#define N_MOUSE 2
#define N_PPP 3
#define N_STRIP 4
#define N_AX25 5
#define N_X25 6 /* X.25 async */
#define N_6PACK 7
#define N_MASC 8 /* Reserved for Mobitex module <kaz@cafe.net> */
#define N_R3964 9 /* Reserved for Simatic R3964 module */
#define N_PROFIBUS_FDL 10 /* Reserved for Profibus <Dave@mvhi.com> */
#define N_IRDA 11 /* Linux IrDa - http://irda.sourceforge.net/ */
#define N_SMSBLOCK 12 /* SMS block mode - for talking to GSM data */
/* cards about SMS messages */
#define N_HDLC 13 /* synchronous HDLC */
#define N_SYNC_PPP 14 /* synchronous PPP */
#define N_HCI 15 /* Bluetooth HCI UART */
#define N_GIGASET_M101 16 /* Siemens Gigaset M101 serial DECT adapter */
/*
* This character is the same as _POSIX_VDISABLE: it cannot be used as
* a c_cc[] character, but indicates that a particular special character
* isn't in use (eg VINTR has no character etc)
*/
#define __DISABLED_CHAR '\0'
/*
* This is the flip buffer used for the tty driver. The buffer is
* located in the tty structure, and is used as a high speed interface
* between the tty driver and the tty line discipline.
*/
#define TTY_FLIPBUF_SIZE 512
struct tty_buffer {
struct tty_buffer *next;
char *char_buf_ptr;
unsigned char *flag_buf_ptr;
int used;
int size;
int commit;
int read;
/* Data points here */
unsigned long data[0];
};
struct tty_bufhead {
struct delayed_work work;
struct semaphore pty_sem;
spinlock_t lock;
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */
struct tty_buffer *free; /* Free queue head */
int memory_used; /* Buffer space used excluding free queue */
};
/*
* The pty uses char_buf and flag_buf as a contiguous buffer
*/
#define PTY_BUF_SIZE 4*TTY_FLIPBUF_SIZE
/*
* When a break, frame error, or parity error happens, these codes are
* stuffed into the flags buffer.
*/
#define TTY_NORMAL 0
#define TTY_BREAK 1
#define TTY_FRAME 2
#define TTY_PARITY 3
#define TTY_OVERRUN 4
#define INTR_CHAR(tty) ((tty)->termios->c_cc[VINTR])
#define QUIT_CHAR(tty) ((tty)->termios->c_cc[VQUIT])
#define ERASE_CHAR(tty) ((tty)->termios->c_cc[VERASE])
#define KILL_CHAR(tty) ((tty)->termios->c_cc[VKILL])
#define EOF_CHAR(tty) ((tty)->termios->c_cc[VEOF])
#define TIME_CHAR(tty) ((tty)->termios->c_cc[VTIME])
#define MIN_CHAR(tty) ((tty)->termios->c_cc[VMIN])
#define SWTC_CHAR(tty) ((tty)->termios->c_cc[VSWTC])
#define START_CHAR(tty) ((tty)->termios->c_cc[VSTART])
#define STOP_CHAR(tty) ((tty)->termios->c_cc[VSTOP])
#define SUSP_CHAR(tty) ((tty)->termios->c_cc[VSUSP])
#define EOL_CHAR(tty) ((tty)->termios->c_cc[VEOL])
#define REPRINT_CHAR(tty) ((tty)->termios->c_cc[VREPRINT])
#define DISCARD_CHAR(tty) ((tty)->termios->c_cc[VDISCARD])
#define WERASE_CHAR(tty) ((tty)->termios->c_cc[VWERASE])
#define LNEXT_CHAR(tty) ((tty)->termios->c_cc[VLNEXT])
#define EOL2_CHAR(tty) ((tty)->termios->c_cc[VEOL2])
#define _I_FLAG(tty,f) ((tty)->termios->c_iflag & (f))
#define _O_FLAG(tty,f) ((tty)->termios->c_oflag & (f))
#define _C_FLAG(tty,f) ((tty)->termios->c_cflag & (f))
#define _L_FLAG(tty,f) ((tty)->termios->c_lflag & (f))
#define I_IGNBRK(tty) _I_FLAG((tty),IGNBRK)
#define I_BRKINT(tty) _I_FLAG((tty),BRKINT)
#define I_IGNPAR(tty) _I_FLAG((tty),IGNPAR)
#define I_PARMRK(tty) _I_FLAG((tty),PARMRK)
#define I_INPCK(tty) _I_FLAG((tty),INPCK)
#define I_ISTRIP(tty) _I_FLAG((tty),ISTRIP)
#define I_INLCR(tty) _I_FLAG((tty),INLCR)
#define I_IGNCR(tty) _I_FLAG((tty),IGNCR)
#define I_ICRNL(tty) _I_FLAG((tty),ICRNL)
#define I_IUCLC(tty) _I_FLAG((tty),IUCLC)
#define I_IXON(tty) _I_FLAG((tty),IXON)
#define I_IXANY(tty) _I_FLAG((tty),IXANY)
#define I_IXOFF(tty) _I_FLAG((tty),IXOFF)
#define I_IMAXBEL(tty) _I_FLAG((tty),IMAXBEL)
#define I_IUTF8(tty) _I_FLAG((tty),IUTF8)
#define O_OPOST(tty) _O_FLAG((tty),OPOST)
#define O_OLCUC(tty) _O_FLAG((tty),OLCUC)
#define O_ONLCR(tty) _O_FLAG((tty),ONLCR)
#define O_OCRNL(tty) _O_FLAG((tty),OCRNL)
#define O_ONOCR(tty) _O_FLAG((tty),ONOCR)
#define O_ONLRET(tty) _O_FLAG((tty),ONLRET)
#define O_OFILL(tty) _O_FLAG((tty),OFILL)
#define O_OFDEL(tty) _O_FLAG((tty),OFDEL)
#define O_NLDLY(tty) _O_FLAG((tty),NLDLY)
#define O_CRDLY(tty) _O_FLAG((tty),CRDLY)
#define O_TABDLY(tty) _O_FLAG((tty),TABDLY)
#define O_BSDLY(tty) _O_FLAG((tty),BSDLY)
#define O_VTDLY(tty) _O_FLAG((tty),VTDLY)
#define O_FFDLY(tty) _O_FLAG((tty),FFDLY)
#define C_BAUD(tty) _C_FLAG((tty),CBAUD)
#define C_CSIZE(tty) _C_FLAG((tty),CSIZE)
#define C_CSTOPB(tty) _C_FLAG((tty),CSTOPB)
#define C_CREAD(tty) _C_FLAG((tty),CREAD)
#define C_PARENB(tty) _C_FLAG((tty),PARENB)
#define C_PARODD(tty) _C_FLAG((tty),PARODD)
#define C_HUPCL(tty) _C_FLAG((tty),HUPCL)
#define C_CLOCAL(tty) _C_FLAG((tty),CLOCAL)
#define C_CIBAUD(tty) _C_FLAG((tty),CIBAUD)
#define C_CRTSCTS(tty) _C_FLAG((tty),CRTSCTS)
#define L_ISIG(tty) _L_FLAG((tty),ISIG)
#define L_ICANON(tty) _L_FLAG((tty),ICANON)
#define L_XCASE(tty) _L_FLAG((tty),XCASE)
#define L_ECHO(tty) _L_FLAG((tty),ECHO)
#define L_ECHOE(tty) _L_FLAG((tty),ECHOE)
#define L_ECHOK(tty) _L_FLAG((tty),ECHOK)
#define L_ECHONL(tty) _L_FLAG((tty),ECHONL)
#define L_NOFLSH(tty) _L_FLAG((tty),NOFLSH)
#define L_TOSTOP(tty) _L_FLAG((tty),TOSTOP)
#define L_ECHOCTL(tty) _L_FLAG((tty),ECHOCTL)
#define L_ECHOPRT(tty) _L_FLAG((tty),ECHOPRT)
#define L_ECHOKE(tty) _L_FLAG((tty),ECHOKE)
#define L_FLUSHO(tty) _L_FLAG((tty),FLUSHO)
#define L_PENDIN(tty) _L_FLAG((tty),PENDIN)
#define L_IEXTEN(tty) _L_FLAG((tty),IEXTEN)
struct device;
/*
* Where all of the state associated with a tty is kept while the tty
* is open. Since the termios state should be kept even if the tty
* has been closed --- for things like the baud rate, etc --- it is
* not stored here, but rather a pointer to the real state is stored
* here. Possible the winsize structure should have the same
* treatment, but (1) the default 80x24 is usually right and (2) it's
* most often used by a windowing system, which will set the correct
* size each time the window is created or resized anyway.
* - TYT, 9/14/92
*/
struct tty_struct {
int magic;
struct tty_driver *driver;
int index;
struct tty_ldisc ldisc;
struct mutex termios_mutex;
struct ktermios *termios, *termios_locked;
char name[64];
struct pid *pgrp;
struct pid *session;
unsigned long flags;
int count;
struct winsize winsize;
unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
unsigned char low_latency:1, warned:1;
unsigned char ctrl_status;
unsigned int receive_room; /* Bytes free for queue */
struct tty_struct *link;
struct fasync_struct *fasync;
struct tty_bufhead buf;
int alt_speed; /* For magic substitution of 38400 bps */
wait_queue_head_t write_wait;
wait_queue_head_t read_wait;
struct work_struct hangup_work;
void *disc_data;
void *driver_data;
struct list_head tty_files;
#define N_TTY_BUF_SIZE 4096
/*
* The following is data for the N_TTY line discipline. For
* historical reasons, this is included in the tty structure.
*/
unsigned int column;
unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
unsigned char closing:1;
unsigned short minimum_to_wake;
unsigned long overrun_time;
int num_overrun;
unsigned long process_char_map[256/(8*sizeof(unsigned long))];
char *read_buf;
int read_head;
int read_tail;
int read_cnt;
unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
int canon_data;
unsigned long canon_head;
unsigned int canon_column;
struct mutex atomic_read_lock;
struct mutex atomic_write_lock;
unsigned char *write_buf;
int write_cnt;
spinlock_t read_lock;
/* If the tty has a pending do_SAK, queue it here - akpm */
struct work_struct SAK_work;
};
/* tty magic number */
#define TTY_MAGIC 0x5401
/*
* These bits are used in the flags field of the tty structure.
*
* So that interrupts won't be able to mess up the queues,
* copy_to_cooked must be atomic with respect to itself, as must
* tty->write. Thus, you must use the inline functions set_bit() and
* clear_bit() to make things atomic.
*/
#define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */
#define TTY_IO_ERROR 1 /* Canse an I/O error (may be no ldisc too) */
#define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */
#define TTY_EXCLUSIVE 3 /* Exclusive open mode */
#define TTY_DEBUG 4 /* Debugging */
#define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
#define TTY_PUSH 6 /* n_tty private */
#define TTY_CLOSING 7 /* ->close() in progress */
#define TTY_LDISC 9 /* Line discipline attached */
#define TTY_HW_COOK_OUT 14 /* Hardware can do output cooking */
#define TTY_HW_COOK_IN 15 /* Hardware can do input cooking */
#define TTY_PTY_LOCK 16 /* pty private */
#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
#define TTY_HUPPED 18 /* Post driver->hangup() */
#define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
extern void tty_write_flush(struct tty_struct *);
extern struct ktermios tty_std_termios;
extern int kmsg_redirect;
extern void console_init(void);
extern int vcs_init(void);
extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
const char *routine);
extern char *tty_name(struct tty_struct *tty, char *buf);
extern void tty_wait_until_sent(struct tty_struct * tty, long timeout);
extern int tty_check_change(struct tty_struct * tty);
extern void stop_tty(struct tty_struct * tty);
extern void start_tty(struct tty_struct * tty);
extern int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc);
extern int tty_unregister_ldisc(int disc);
extern int tty_register_driver(struct tty_driver *driver);
extern int tty_unregister_driver(struct tty_driver *driver);
extern struct device *tty_register_device(struct tty_driver *driver,
unsigned index, struct device *dev);
extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
int buflen);
extern void tty_write_message(struct tty_struct *tty, char *msg);
extern int is_current_pgrp_orphaned(void);
extern int is_ignored(int sig);
extern int tty_signal(int sig, struct tty_struct *tty);
extern void tty_hangup(struct tty_struct * tty);
extern void tty_vhangup(struct tty_struct * tty);
extern void tty_unhangup(struct file *filp);
extern int tty_hung_up_p(struct file * filp);
extern void do_SAK(struct tty_struct *tty);
extern void __do_SAK(struct tty_struct *tty);
extern void disassociate_ctty(int priv);
extern void no_tty(void);
extern void tty_flip_buffer_push(struct tty_struct *tty);
extern speed_t tty_get_baud_rate(struct tty_struct *tty);
extern speed_t tty_termios_baud_rate(struct ktermios *termios);
extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
extern void tty_ldisc_deref(struct tty_ldisc *);
extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
extern struct tty_ldisc *tty_ldisc_get(int);
extern void tty_ldisc_put(int);
extern void tty_wakeup(struct tty_struct *tty);
extern void tty_ldisc_flush(struct tty_struct *tty);
extern int tty_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg);
extern dev_t tty_devnum(struct tty_struct *tty);
extern void proc_clear_tty(struct task_struct *p);
extern struct tty_struct *get_current_tty(void);
extern struct mutex tty_mutex;
/* n_tty.c */
extern struct tty_ldisc tty_ldisc_N_TTY;
/* tty_ioctl.c */
extern int n_tty_ioctl(struct tty_struct * tty, struct file * file,
unsigned int cmd, unsigned long arg);
/* serial.c */
extern void serial_console_init(void);
/* pcxx.c */
extern int pcxe_open(struct tty_struct *tty, struct file *filp);
/* printk.c */
extern void console_print(const char *);
/* vt.c */
extern int vt_ioctl(struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg);
#endif /* __KERNEL__ */
#endif
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