diff options
| -rw-r--r-- | drivers/char/selection.c | 2 | ||||
| -rw-r--r-- | drivers/char/tty_io.c | 29 | ||||
| -rw-r--r-- | drivers/char/vt.c | 12 | ||||
| -rw-r--r-- | drivers/char/vt_ioctl.c | 17 | ||||
| -rw-r--r-- | include/linux/vt_kern.h | 3 |
5 files changed, 36 insertions, 27 deletions
diff --git a/drivers/char/selection.c b/drivers/char/selection.c index 71093a9fc462..74cff839c857 100644 --- a/drivers/char/selection.c +++ b/drivers/char/selection.c @@ -33,7 +33,7 @@ extern void poke_blanked_console(void); /* Variables for selection control. */ /* Use a dynamic buffer, instead of static (Dec 1994) */ -struct vc_data *sel_cons; /* must not be disallocated */ +struct vc_data *sel_cons; /* must not be deallocated */ static volatile int sel_start = -1; /* cleared by clear_selection */ static int sel_end; static int sel_buffer_lth; diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index eb881cfa53e0..2a1e95b0f282 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2770,12 +2770,11 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) * actually has driver level meaning and triggers a VC resize. * * Locking: - * The console_sem is used to ensure we do not try and resize - * the console twice at once. - * FIXME: Two racing size sets may leave the console and kernel - * parameters disagreeing. Is this exploitable ? - * FIXME: Random values racing a window size get is wrong - * should lock here against that + * Called function use the console_sem is used to ensure we do + * not try and resize the console twice at once. + * The tty->termios_sem is used to ensure we don't double + * resize and get confused. Lock order - tty->termios.sem before + * console sem */ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, @@ -2785,17 +2784,17 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) return -EFAULT; + + down(&tty->termios_sem); if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) - return 0; + goto done; + #ifdef CONFIG_VT if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { - int rc; - - acquire_console_sem(); - rc = vc_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row); - release_console_sem(); - if (rc) - return -ENXIO; + if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row)) { + up(&tty->termios_sem); + return -ENXIO; + } } #endif if (tty->pgrp > 0) @@ -2804,6 +2803,8 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, kill_pg(real_tty->pgrp, SIGWINCH, 1); tty->winsize = tmp_ws; real_tty->winsize = tmp_ws; +done: + up(&tty->termios_sem); return 0; } diff --git a/drivers/char/vt.c b/drivers/char/vt.c index 0fca83ededff..b49f03375439 100644 --- a/drivers/char/vt.c +++ b/drivers/char/vt.c @@ -885,8 +885,17 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int lines) return err; } +int vc_lock_resize(struct vc_data *vc, unsigned int cols, unsigned int lines) +{ + int rc; + + acquire_console_sem(); + rc = vc_resize(vc, cols, lines); + release_console_sem(); + return rc; +} -void vc_disallocate(unsigned int currcons) +void vc_deallocate(unsigned int currcons) { WARN_CONSOLE_UNLOCKED(); @@ -3790,6 +3799,7 @@ EXPORT_SYMBOL(default_blu); EXPORT_SYMBOL(update_region); EXPORT_SYMBOL(redraw_screen); EXPORT_SYMBOL(vc_resize); +EXPORT_SYMBOL(vc_lock_resize); EXPORT_SYMBOL(fg_console); EXPORT_SYMBOL(console_blank_hook); EXPORT_SYMBOL(console_blanked); diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c index a5628a8b6620..a53e382cc107 100644 --- a/drivers/char/vt_ioctl.c +++ b/drivers/char/vt_ioctl.c @@ -96,7 +96,7 @@ do_kdsk_ioctl(int cmd, struct kbentry __user *user_kbe, int perm, struct kbd_str if (!perm) return -EPERM; if (!i && v == K_NOSUCHMAP) { - /* disallocate map */ + /* deallocate map */ key_map = key_maps[s]; if (s && key_map) { key_maps[s] = NULL; @@ -819,20 +819,20 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, if (arg > MAX_NR_CONSOLES) return -ENXIO; if (arg == 0) { - /* disallocate all unused consoles, but leave 0 */ + /* deallocate all unused consoles, but leave 0 */ acquire_console_sem(); for (i=1; i<MAX_NR_CONSOLES; i++) if (! VT_BUSY(i)) - vc_disallocate(i); + vc_deallocate(i); release_console_sem(); } else { - /* disallocate a single console, if possible */ + /* deallocate a single console, if possible */ arg--; if (VT_BUSY(arg)) return -EBUSY; if (arg) { /* leave 0 */ acquire_console_sem(); - vc_disallocate(arg); + vc_deallocate(arg); release_console_sem(); } } @@ -847,11 +847,8 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, if (get_user(ll, &vtsizes->v_rows) || get_user(cc, &vtsizes->v_cols)) return -EFAULT; - for (i = 0; i < MAX_NR_CONSOLES; i++) { - acquire_console_sem(); - vc_resize(vc_cons[i].d, cc, ll); - release_console_sem(); - } + for (i = 0; i < MAX_NR_CONSOLES; i++) + vc_lock_resize(vc_cons[i].d, cc, ll); return 0; } diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h index 918a29763aea..1009d3fe1fc2 100644 --- a/include/linux/vt_kern.h +++ b/include/linux/vt_kern.h @@ -33,7 +33,8 @@ extern int fg_console, last_console, want_console; int vc_allocate(unsigned int console); int vc_cons_allocated(unsigned int console); int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int lines); -void vc_disallocate(unsigned int console); +int vc_lock_resize(struct vc_data *vc, unsigned int cols, unsigned int lines); +void vc_deallocate(unsigned int console); void reset_palette(struct vc_data *vc); void do_blank_screen(int entering_gfx); void do_unblank_screen(int leaving_gfx); |