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| author | Thomas Gleixner <tglx@linutronix.de> | 2009-12-09 14:33:48 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2010-02-21 20:20:07 +0100 |
| commit | 378cc63c24b6c9b9269c05475fbefeb8335790b3 (patch) | |
| tree | bb7c70e1192199236d448e3e1760a978f73ea15d | |
| parent | 4c9a0a35cd3c2984a3c58bc22c7214472d01c9c9 (diff) | |
| download | lwn-378cc63c24b6c9b9269c05475fbefeb8335790b3.tar.gz lwn-378cc63c24b6c9b9269c05475fbefeb8335790b3.zip | |
audit: Use rcu for task lookup protection
Protect the task lookups in audit_receive_msg() with rcu_read_lock()
instead of tasklist_lock and use lock/unlock_sighand to protect
against the exit race.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
| -rw-r--r-- | kernel/audit.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index bf307ddf7d03..8ccf8d5a874c 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -880,17 +880,16 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) case AUDIT_TTY_GET: { struct audit_tty_status s; struct task_struct *tsk; + unsigned long flags; - read_lock(&tasklist_lock); + rcu_read_lock(); tsk = find_task_by_vpid(pid); - if (!tsk) - err = -ESRCH; - else { - spin_lock_irq(&tsk->sighand->siglock); + if (tsk && lock_task_sighand(tsk, &flags)) { s.enabled = tsk->signal->audit_tty != 0; - spin_unlock_irq(&tsk->sighand->siglock); - } - read_unlock(&tasklist_lock); + unlock_task_sighand(tsk, &flags); + } else + err = -ESRCH; + rcu_read_unlock(); if (!err) audit_send_reply(NETLINK_CB(skb).pid, seq, @@ -900,22 +899,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) case AUDIT_TTY_SET: { struct audit_tty_status *s; struct task_struct *tsk; + unsigned long flags; if (nlh->nlmsg_len < sizeof(struct audit_tty_status)) return -EINVAL; s = data; if (s->enabled != 0 && s->enabled != 1) return -EINVAL; - read_lock(&tasklist_lock); + rcu_read_lock(); tsk = find_task_by_vpid(pid); - if (!tsk) - err = -ESRCH; - else { - spin_lock_irq(&tsk->sighand->siglock); + if (tsk && lock_task_sighand(tsk, &flags)) { tsk->signal->audit_tty = s->enabled != 0; - spin_unlock_irq(&tsk->sighand->siglock); - } - read_unlock(&tasklist_lock); + unlock_task_sighand(tsk, &flags); + } else + err = -ESRCH; + rcu_read_unlock(); break; } default: |