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[PATCH] tty: ->signal->tty locking

Fix the locking of signal->tty.

Use ->sighand->siglock to protect ->signal->tty; this lock is already used
by most other members of ->signal/->sighand.  And unless we are 'current'
or the tasklist_lock is held we need ->siglock to access ->signal anyway.

(NOTE: sys_unshare() is broken wrt ->sighand locking rules)

Note that tty_mutex is held over tty destruction, so while holding
tty_mutex any tty pointer remains valid.  Otherwise the lifetime of ttys
are governed by their open file handles.  This leaves some holes for tty
access from signal->tty (or any other non file related tty access).

It solves the tty SLAB scribbles we were seeing.

(NOTE: the change from group_send_sig_info to __group_send_sig_info needs to
       be examined by someone familiar with the security framework, I think
       it is safe given the SEND_SIG_PRIV from other __group_send_sig_info
       invocations)

[schwidefsky@de.ibm.com: 3270 fix]
[akpm@osdl.org: various post-viro fixes]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
master
Peter Zijlstra 15 years ago
committed by Linus Torvalds
parent
commit
24ec839c43
  1. 4
      arch/sparc64/solaris/misc.c
  2. 7
      arch/um/kernel/exec.c
  3. 237
      drivers/char/tty_io.c
  4. 12
      drivers/s390/char/fs3270.c
  5. 14
      fs/dquot.c
  6. 1
      fs/open.c
  7. 11
      include/linux/tty.h
  8. 9
      kernel/acct.c
  9. 2
      kernel/auditsc.c
  10. 4
      kernel/exit.c
  11. 6
      kernel/sys.c
  12. 11
      security/selinux/hooks.c

4
arch/sparc64/solaris/misc.c

@ -423,9 +423,7 @@ asmlinkage int solaris_procids(int cmd, s32 pid, s32 pgid)
Solaris setpgrp and setsid? */
ret = sys_setpgid(0, 0);
if (ret) return ret;
mutex_lock(&tty_mutex);
current->signal->tty = NULL;
mutex_unlock(&tty_mutex);
proc_clear_tty(current);
return process_group(current);
}
case 2: /* getsid */

7
arch/um/kernel/exec.c

@ -39,12 +39,13 @@ static long execve1(char *file, char __user * __user *argv,
char __user *__user *env)
{
long error;
struct tty_struct *tty;
#ifdef CONFIG_TTY_LOG
mutex_lock(&tty_mutex);
task_lock(current); /* FIXME: is this needed ? */
log_exec(argv, current->signal->tty);
task_unlock(current);
tty = get_current_tty();
if (tty)
log_exec(argv, tty);
mutex_unlock(&tty_mutex);
#endif
error = do_execve(file, argv, env, &current->thread.regs);

237
drivers/char/tty_io.c

@ -126,7 +126,7 @@ EXPORT_SYMBOL(tty_std_termios);
LIST_HEAD(tty_drivers); /* linked list of tty drivers */
/* Semaphore to protect creating and releasing a tty. This is shared with
/* Mutex to protect creating and releasing a tty. This is shared with
vt.c for deeply disgusting hack reasons */
DEFINE_MUTEX(tty_mutex);
EXPORT_SYMBOL(tty_mutex);
@ -250,7 +250,7 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
"!= #fd's(%d) in %s\n",
tty->name, tty->count, count, routine);
return count;
}
}
#endif
return 0;
}
@ -259,18 +259,6 @@ static int check_tty_count(struct tty_struct *tty, const char *routine)
* Tty buffer allocation management
*/
/**
* tty_buffer_free_all - free buffers used by a tty
* @tty: tty to free from
*
* Remove all the buffers pending on a tty whether queued with data
* or in the free ring. Must be called when the tty is no longer in use
*
* Locking: none
*/
/**
* tty_buffer_free_all - free buffers used by a tty
* @tty: tty to free from
@ -614,7 +602,7 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
* they are not on hot paths so a little discipline won't do
* any harm.
*
* Locking: takes termios_sem
* Locking: takes termios_mutex
*/
static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
@ -915,7 +903,7 @@ static void tty_ldisc_enable(struct tty_struct *tty)
* context.
*
* Locking: takes tty_ldisc_lock.
* called functions take termios_sem
* called functions take termios_mutex
*/
static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
@ -1267,12 +1255,12 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
*
* Locking:
* BKL
* redirect lock for undoing redirection
* file list lock for manipulating list of ttys
* tty_ldisc_lock from called functions
* termios_sem resetting termios data
* tasklist_lock to walk task list for hangup event
*
* redirect lock for undoing redirection
* file list lock for manipulating list of ttys
* tty_ldisc_lock from called functions
* termios_mutex resetting termios data
* tasklist_lock to walk task list for hangup event
* ->siglock to protect ->signal/->sighand
*/
static void do_tty_hangup(struct work_struct *work)
{
@ -1354,14 +1342,18 @@ static void do_tty_hangup(struct work_struct *work)
read_lock(&tasklist_lock);
if (tty->session > 0) {
do_each_task_pid(tty->session, PIDTYPE_SID, p) {
spin_lock_irq(&p->sighand->siglock);
if (p->signal->tty == tty)
p->signal->tty = NULL;
if (!p->signal->leader)
if (!p->signal->leader) {
spin_unlock_irq(&p->sighand->siglock);
continue;
group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
}
__group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
__group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
if (tty->pgrp > 0)
p->signal->tty_old_pgrp = tty->pgrp;
spin_unlock_irq(&p->sighand->siglock);
} while_each_task_pid(tty->session, PIDTYPE_SID, p);
}
read_unlock(&tasklist_lock);
@ -1453,6 +1445,14 @@ int tty_hung_up_p(struct file * filp)
EXPORT_SYMBOL(tty_hung_up_p);
static void session_clear_tty(pid_t session)
{
struct task_struct *p;
do_each_task_pid(session, PIDTYPE_SID, p) {
proc_clear_tty(p);
} while_each_task_pid(session, PIDTYPE_SID, p);
}
/**
* disassociate_ctty - disconnect controlling tty
* @on_exit: true if exiting so need to "hang up" the session
@ -1469,31 +1469,35 @@ EXPORT_SYMBOL(tty_hung_up_p);
* The argument on_exit is set to 1 if called when a process is
* exiting; it is 0 if called by the ioctl TIOCNOTTY.
*
* Locking: tty_mutex is taken to protect current->signal->tty
* Locking:
* BKL is taken for hysterical raisins
* Tasklist lock is taken (under tty_mutex) to walk process
* lists for the session.
* tty_mutex is taken to protect tty
* ->siglock is taken to protect ->signal/->sighand
* tasklist_lock is taken to walk process list for sessions
* ->siglock is taken to protect ->signal/->sighand
*/
void disassociate_ctty(int on_exit)
{
struct tty_struct *tty;
struct task_struct *p;
int tty_pgrp = -1;
int session;
lock_kernel();
mutex_lock(&tty_mutex);
tty = current->signal->tty;
tty = get_current_tty();
if (tty) {
tty_pgrp = tty->pgrp;
mutex_unlock(&tty_mutex);
/* XXX: here we race, there is nothing protecting tty */
if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
tty_vhangup(tty);
} else {
if (current->signal->tty_old_pgrp) {
kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);
kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);
pid_t old_pgrp = current->signal->tty_old_pgrp;
if (old_pgrp) {
kill_pg(old_pgrp, SIGHUP, on_exit);
kill_pg(old_pgrp, SIGCONT, on_exit);
}
mutex_unlock(&tty_mutex);
unlock_kernel();
@ -1505,19 +1509,29 @@ void disassociate_ctty(int on_exit)
kill_pg(tty_pgrp, SIGCONT, on_exit);
}
/* Must lock changes to tty_old_pgrp */
mutex_lock(&tty_mutex);
spin_lock_irq(&current->sighand->siglock);
current->signal->tty_old_pgrp = 0;
tty->session = 0;
tty->pgrp = -1;
session = current->signal->session;
spin_unlock_irq(&current->sighand->siglock);
mutex_lock(&tty_mutex);
/* It is possible that do_tty_hangup has free'd this tty */
tty = get_current_tty();
if (tty) {
tty->session = 0;
tty->pgrp = 0;
} else {
#ifdef TTY_DEBUG_HANGUP
printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
" = NULL", tty);
#endif
}
mutex_unlock(&tty_mutex);
/* Now clear signal->tty under the lock */
read_lock(&tasklist_lock);
do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
} while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
session_clear_tty(session);
read_unlock(&tasklist_lock);
mutex_unlock(&tty_mutex);
unlock_kernel();
}
@ -2337,16 +2351,10 @@ static void release_dev(struct file * filp)
* tty.
*/
if (tty_closing || o_tty_closing) {
struct task_struct *p;
read_lock(&tasklist_lock);
do_each_task_pid(tty->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
} while_each_task_pid(tty->session, PIDTYPE_SID, p);
session_clear_tty(tty->session);
if (o_tty)
do_each_task_pid(o_tty->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
} while_each_task_pid(o_tty->session, PIDTYPE_SID, p);
session_clear_tty(o_tty->session);
read_unlock(&tasklist_lock);
}
@ -2443,9 +2451,9 @@ static void release_dev(struct file * filp)
* The termios state of a pty is reset on first open so that
* settings don't persist across reuse.
*
* Locking: tty_mutex protects current->signal->tty, get_tty_driver and
* init_dev work. tty->count should protect the rest.
* task_lock is held to update task details for sessions
* Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
* tty->count should protect the rest.
* ->siglock protects ->signal/->sighand
*/
static int tty_open(struct inode * inode, struct file * filp)
@ -2467,12 +2475,13 @@ retry_open:
mutex_lock(&tty_mutex);
if (device == MKDEV(TTYAUX_MAJOR,0)) {
if (!current->signal->tty) {
tty = get_current_tty();
if (!tty) {
mutex_unlock(&tty_mutex);
return -ENXIO;
}
driver = current->signal->tty->driver;
index = current->signal->tty->index;
driver = tty->driver;
index = tty->index;
filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
/* noctty = 1; */
goto got_driver;
@ -2547,17 +2556,16 @@ got_driver:
filp->f_op = &tty_fops;
goto retry_open;
}
mutex_lock(&tty_mutex);
spin_lock_irq(&current->sighand->siglock);
if (!noctty &&
current->signal->leader &&
!current->signal->tty &&
tty->session == 0) {
task_lock(current);
current->signal->tty = tty;
task_unlock(current);
current->signal->tty_old_pgrp = 0;
tty->session = current->signal->session;
tty->pgrp = process_group(current);
}
tty->session == 0)
__proc_set_tty(current, tty);
spin_unlock_irq(&current->sighand->siglock);
mutex_unlock(&tty_mutex);
return 0;
}
@ -2747,7 +2755,7 @@ static int tiocsti(struct tty_struct *tty, char __user *p)
*
* Copies the kernel idea of the window size into the user buffer.
*
* Locking: tty->termios_sem is taken to ensure the winsize data
* Locking: tty->termios_mutex is taken to ensure the winsize data
* is consistent.
*/
@ -2774,8 +2782,8 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
* Locking:
* 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
* The tty->termios_mutex is used to ensure we don't double
* resize and get confused. Lock order - tty->termios_mutex before
* console sem
*/
@ -2880,25 +2888,28 @@ static int fionbio(struct file *file, int __user *p)
* leader to set this tty as the controlling tty for the session.
*
* Locking:
* Takes tasklist lock internally to walk sessions
* Takes task_lock() when updating signal->tty
* Takes tty_mutex() to protect tty instance
*
* Takes tasklist_lock internally to walk sessions
* Takes ->siglock() when updating signal->tty
*/
static int tiocsctty(struct tty_struct *tty, int arg)
{
struct task_struct *p;
int ret = 0;
if (current->signal->leader &&
(current->signal->session == tty->session))
return 0;
return ret;
mutex_lock(&tty_mutex);
/*
* The process must be a session leader and
* not have a controlling tty already.
*/
if (!current->signal->leader || current->signal->tty)
return -EPERM;
if (!current->signal->leader || current->signal->tty) {
ret = -EPERM;
goto unlock;
}
if (tty->session > 0) {
/*
* This tty is already the controlling
@ -2908,24 +2919,18 @@ static int tiocsctty(struct tty_struct *tty, int arg)
/*
* Steal it away
*/
read_lock(&tasklist_lock);
do_each_task_pid(tty->session, PIDTYPE_SID, p) {
p->signal->tty = NULL;
} while_each_task_pid(tty->session, PIDTYPE_SID, p);
session_clear_tty(tty->session);
read_unlock(&tasklist_lock);
} else
return -EPERM;
} else {
ret = -EPERM;
goto unlock;
}
}
mutex_lock(&tty_mutex);
task_lock(current);
current->signal->tty = tty;
task_unlock(current);
proc_set_tty(current, tty);
unlock:
mutex_unlock(&tty_mutex);
current->signal->tty_old_pgrp = 0;
tty->session = current->signal->session;
tty->pgrp = process_group(current);
return 0;
return ret;
}
/**
@ -2937,7 +2942,7 @@ static int tiocsctty(struct tty_struct *tty, int arg)
* Obtain the process group of the tty. If there is no process group
* return an error.
*
* Locking: none. Reference to ->signal->tty is safe.
* Locking: none. Reference to current->signal->tty is safe.
*/
static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@ -2995,7 +3000,7 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
* Obtain the session id of the tty. If there is no session
* return an error.
*
* Locking: none. Reference to ->signal->tty is safe.
* Locking: none. Reference to current->signal->tty is safe.
*/
static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@ -3214,14 +3219,11 @@ int tty_ioctl(struct inode * inode, struct file * file,
clear_bit(TTY_EXCLUSIVE, &tty->flags);
return 0;
case TIOCNOTTY:
/* FIXME: taks lock or tty_mutex ? */
if (current->signal->tty != tty)
return -ENOTTY;
if (current->signal->leader)
disassociate_ctty(0);
task_lock(current);
current->signal->tty = NULL;
task_unlock(current);
proc_clear_tty(current);
return 0;
case TIOCSCTTY:
return tiocsctty(tty, arg);
@ -3321,7 +3323,7 @@ static void __do_SAK(struct work_struct *work)
if (!tty)
return;
session = tty->session;
session = tty->session;
/* We don't want an ldisc switch during this */
disc = tty_ldisc_ref(tty);
@ -3834,9 +3836,52 @@ int tty_unregister_driver(struct tty_driver *driver)
cdev_del(&driver->cdev);
return 0;
}
EXPORT_SYMBOL(tty_unregister_driver);
dev_t tty_devnum(struct tty_struct *tty)
{
return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
}
EXPORT_SYMBOL(tty_devnum);
void proc_clear_tty(struct task_struct *p)
{
spin_lock_irq(&p->sighand->siglock);
p->signal->tty = NULL;
spin_unlock_irq(&p->sighand->siglock);
}
EXPORT_SYMBOL(proc_clear_tty);
void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
{
if (tty) {
tty->session = tsk->signal->session;
tty->pgrp = process_group(tsk);
}
tsk->signal->tty = tty;
tsk->signal->tty_old_pgrp = 0;
}
void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
{
spin_lock_irq(&tsk->sighand->siglock);
__proc_set_tty(tsk, tty);
spin_unlock_irq(&tsk->sighand->siglock);
}
struct tty_struct *get_current_tty(void)
{
struct tty_struct *tty;
WARN_ON_ONCE(!mutex_is_locked(&tty_mutex));
tty = current->signal->tty;
/*
* session->tty can be changed/cleared from under us, make sure we
* issue the load. The obtained pointer, when not NULL, is valid as
* long as we hold tty_mutex.
*/
barrier();
return tty;
}
/*
* Initialize the console device. This is called *early*, so

12
drivers/s390/char/fs3270.c

@ -424,11 +424,15 @@ fs3270_open(struct inode *inode, struct file *filp)
minor = iminor(filp->f_dentry->d_inode);
/* Check for minor 0 multiplexer. */
if (minor == 0) {
if (!current->signal->tty)
struct tty_struct *tty;
mutex_lock(&tty_mutex);
tty = get_current_tty();
if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
mutex_unlock(&tty_mutex);
return -ENODEV;
if (current->signal->tty->driver->major != IBM_TTY3270_MAJOR)
return -ENODEV;
minor = current->signal->tty->index + RAW3270_FIRSTMINOR;
}
minor = tty->index + RAW3270_FIRSTMINOR;
mutex_unlock(&tty_mutex);
}
/* Check if some other program is already using fullscreen mode. */
fp = (struct fs3270 *) raw3270_find_view(&fs3270_fn, minor);

14
fs/dquot.c

@ -828,6 +828,7 @@ static inline int need_print_warning(struct dquot *dquot)
static void print_warning(struct dquot *dquot, const char warntype)
{
char *msg = NULL;
struct tty_struct *tty;
int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
@ -835,14 +836,15 @@ static void print_warning(struct dquot *dquot, const char warntype)
return;
mutex_lock(&tty_mutex);
if (!current->signal->tty)
tty = get_current_tty();
if (!tty)
goto out_lock;
tty_write_message(current->signal->tty, dquot->dq_sb->s_id);
tty_write_message(tty, dquot->dq_sb->s_id);
if (warntype == ISOFTWARN || warntype == BSOFTWARN)
tty_write_message(current->signal->tty, ": warning, ");
tty_write_message(tty, ": warning, ");
else
tty_write_message(current->signal->tty, ": write failed, ");
tty_write_message(current->signal->tty, quotatypes[dquot->dq_type]);
tty_write_message(tty, ": write failed, ");
tty_write_message(tty, quotatypes[dquot->dq_type]);
switch (warntype) {
case IHARDWARN:
msg = " file limit reached.\r\n";
@ -863,7 +865,7 @@ static void print_warning(struct dquot *dquot, const char warntype)
msg = " block quota exceeded.\r\n";
break;
}
tty_write_message(current->signal->tty, msg);
tty_write_message(tty, msg);
out_lock:
mutex_unlock(&tty_mutex);
}

1
fs/open.c

@ -1087,6 +1087,7 @@ EXPORT_SYMBOL(sys_close);
asmlinkage long sys_vhangup(void)
{
if (capable(CAP_SYS_TTY_CONFIG)) {
/* XXX: this needs locking */
tty_vhangup(current->signal->tty);
return 0;
}

11
include/linux/tty.h

@ -309,6 +309,12 @@ 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 void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
extern void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
extern struct tty_struct *get_current_tty(void);
extern struct mutex tty_mutex;
/* n_tty.c */
@ -335,10 +341,5 @@ extern void console_print(const char *);
extern int vt_ioctl(struct tty_struct *tty, struct file * file,
unsigned int cmd, unsigned long arg);
static inline dev_t tty_devnum(struct tty_struct *tty)
{
return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
}
#endif /* __KERNEL__ */
#endif

9
kernel/acct.c

@ -428,6 +428,7 @@ static void do_acct_process(struct file *file)
u64 elapsed;
u64 run_time;
struct timespec uptime;
struct tty_struct *tty;
/*
* First check to see if there is enough free_space to continue
@ -485,12 +486,8 @@ static void do_acct_process(struct file *file)
#endif
mutex_lock(&tty_mutex);
/* FIXME: Whoever is responsible for current->signal locking needs
to use the same locking all over the kernel and document it */
read_lock(&tasklist_lock);
ac.ac_tty = current->signal->tty ?
old_encode_dev(tty_devnum(current->signal->tty)) : 0;
read_unlock(&tasklist_lock);
tty = get_current_tty();
ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
mutex_unlock(&tty_mutex);
spin_lock_irq(&current->sighand->siglock);

2
kernel/auditsc.c

@ -826,10 +826,12 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
context->return_code);
mutex_lock(&tty_mutex);
read_lock(&tasklist_lock);
if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
tty = tsk->signal->tty->name;
else
tty = "(none)";
read_unlock(&tasklist_lock);
audit_log_format(ab,
" a0=%lx a1=%lx a2=%lx a3=%lx items=%d"
" ppid=%d pid=%d auid=%u uid=%u gid=%u"

4
kernel/exit.c

@ -384,9 +384,7 @@ void daemonize(const char *name, ...)
exit_mm(current);
set_special_pids(1, 1);
mutex_lock(&tty_mutex);
current->signal->tty = NULL;
mutex_unlock(&tty_mutex);
proc_clear_tty(current);
/* Block and flush all signals */
sigfillset(&blocked);

6
kernel/sys.c

@ -1484,7 +1484,6 @@ asmlinkage long sys_setsid(void)
pid_t session;
int err = -EPERM;
mutex_lock(&tty_mutex);
write_lock_irq(&tasklist_lock);
/* Fail if I am already a session leader */
@ -1504,12 +1503,15 @@ asmlinkage long sys_setsid(void)
group_leader->signal->leader = 1;
__set_special_pids(session, session);
spin_lock(&group_leader->sighand->siglock);
group_leader->signal->tty = NULL;
group_leader->signal->tty_old_pgrp = 0;
spin_unlock(&group_leader->sighand->siglock);
err = process_group(group_leader);
out:
write_unlock_irq(&tasklist_lock);
mutex_unlock(&tty_mutex);
return err;
}

11
security/selinux/hooks.c

@ -1695,9 +1695,10 @@ static inline void flush_unauthorized_files(struct files_struct * files)
struct tty_struct *tty;
struct fdtable *fdt;
long j = -1;
int drop_tty = 0;
mutex_lock(&tty_mutex);
tty = current->signal->tty;
tty = get_current_tty();
if (tty) {
file_list_lock();
file = list_entry(tty->tty_files.next, typeof(*file), f_u.fu_list);
@ -1710,12 +1711,14 @@ static inline void flush_unauthorized_files(struct files_struct * files)
struct inode *inode = file->f_dentry->d_inode;
if (inode_has_perm(current, inode,
FILE__READ | FILE__WRITE, NULL)) {
/* Reset controlling tty. */
current->signal->tty = NULL;
current->signal->tty_old_pgrp = 0;
drop_tty = 1;
}
}
file_list_unlock();
/* Reset controlling tty. */
if (drop_tty)
proc_set_tty(current, NULL);
}
mutex_unlock(&tty_mutex);

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