diff options
| -rw-r--r-- | drivers/char/tty_io.c | 24 | ||||
| -rw-r--r-- | include/linux/kernel.h | 3 | ||||
| -rw-r--r-- | kernel/exit.c | 16 |
3 files changed, 26 insertions, 17 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index abfe24d28c5..95f3596189c 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2990,7 +2990,8 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { - pid_t pgrp; + struct pid *pgrp; + pid_t pgrp_nr; int retval = tty_check_change(real_tty); if (retval == -EIO) @@ -3001,14 +3002,23 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t (current->signal->tty != real_tty) || (real_tty->session != process_session(current))) return -ENOTTY; - if (get_user(pgrp, p)) + if (get_user(pgrp_nr, p)) return -EFAULT; - if (pgrp < 0) + if (pgrp_nr < 0) return -EINVAL; - if (session_of_pgrp(pgrp) != process_session(current)) - return -EPERM; - real_tty->pgrp = pgrp; - return 0; + rcu_read_lock(); + pgrp = find_pid(pgrp_nr); + retval = -ESRCH; + if (!pgrp) + goto out_unlock; + retval = -EPERM; + if (session_of_pgrp(pgrp) != task_session(current)) + goto out_unlock; + retval = 0; + real_tty->pgrp = pgrp_nr; +out_unlock: + rcu_read_unlock(); + return retval; } /** diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3531764318f..9ddf25c2153 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -134,7 +134,8 @@ extern unsigned long long memparse(char *ptr, char **retptr); extern int core_kernel_text(unsigned long addr); extern int __kernel_text_address(unsigned long addr); extern int kernel_text_address(unsigned long addr); -extern int session_of_pgrp(int pgrp); +struct pid; +extern struct pid *session_of_pgrp(struct pid *pgrp); extern void dump_thread(struct pt_regs *regs, struct user *dump); diff --git a/kernel/exit.c b/kernel/exit.c index 14f17033f56..3ac6a7a6f85 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -185,21 +185,19 @@ repeat: * This checks not only the pgrp, but falls back on the pid if no * satisfactory pgrp is found. I dunno - gdb doesn't work correctly * without this... + * + * The caller must hold rcu lock or the tasklist lock. */ -int session_of_pgrp(int pgrp) +struct pid *session_of_pgrp(struct pid *pgrp) { struct task_struct *p; - int sid = 0; - - read_lock(&tasklist_lock); + struct pid *sid = NULL; - p = find_task_by_pid_type(PIDTYPE_PGID, pgrp); + p = pid_task(pgrp, PIDTYPE_PGID); if (p == NULL) - p = find_task_by_pid(pgrp); + p = pid_task(pgrp, PIDTYPE_PID); if (p != NULL) - sid = process_session(p); - - read_unlock(&tasklist_lock); + sid = task_session(p); return sid; } |