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authorThomas Gleixner <tglx@linutronix.de>2009-12-09 14:19:41 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2010-10-30 08:45:42 -0400
commitab263f47c9781a644de8b28013434b645082922e (patch)
treebae72a448f5d5f37fb5c762a4c336fe731523dfd
parentaudit: Do not send uninitialized data for AUDIT_TTY_GET (diff)
downloadlinux-dev-ab263f47c9781a644de8b28013434b645082922e.tar.xz
linux-dev-ab263f47c9781a644de8b28013434b645082922e.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> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--kernel/audit.c30
1 files changed, 14 insertions, 16 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index 57f4038694d1..77770a034d59 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -873,17 +873,16 @@ 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,
@@ -893,22 +892,21 @@ 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: