audit: use spin_lock_irqsave/restore in audit tty code
Eric Paris [Tue, 30 Apr 2013 15:01:14 +0000 (11:01 -0400)]
Some of the callers of the audit tty function use spin_lock_irqsave/restore.
We were using the forced always enable version, which seems really bad.
Since I don't know every one of these code paths well enough, it makes
sense to just switch everything to the safe version.  Maybe it's a
little overzealous, but it's a lot better than an unlucky deadlock when
we return to a caller with irq enabled and they expect it to be
disabled.

Signed-off-by: Eric Paris <eparis@redhat.com>

drivers/tty/tty_audit.c
kernel/audit.c

index ea2e5ad..755d418 100644 (file)
@@ -111,11 +111,12 @@ static void tty_audit_buf_push(struct tty_audit_buf *buf)
 void tty_audit_exit(void)
 {
        struct tty_audit_buf *buf;
+       unsigned long flags;
 
-       spin_lock_irq(&current->sighand->siglock);
+       spin_lock_irqsave(&current->sighand->siglock, flags);
        buf = current->signal->tty_audit_buf;
        current->signal->tty_audit_buf = NULL;
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_unlock_irqrestore(&current->sighand->siglock, flags);
        if (!buf)
                return;
 
@@ -133,9 +134,11 @@ void tty_audit_exit(void)
  */
 void tty_audit_fork(struct signal_struct *sig)
 {
-       spin_lock_irq(&current->sighand->siglock);
+       unsigned long flags;
+
+       spin_lock_irqsave(&current->sighand->siglock, flags);
        sig->audit_tty = current->signal->audit_tty;
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_unlock_irqrestore(&current->sighand->siglock, flags);
 }
 
 /**
@@ -145,13 +148,14 @@ void tty_audit_tiocsti(struct tty_struct *tty, char ch)
 {
        struct tty_audit_buf *buf;
        int major, minor, should_audit;
+       unsigned long flags;
 
-       spin_lock_irq(&current->sighand->siglock);
+       spin_lock_irqsave(&current->sighand->siglock, flags);
        should_audit = current->signal->audit_tty;
        buf = current->signal->tty_audit_buf;
        if (buf)
                atomic_inc(&buf->count);
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
        major = tty->driver->major;
        minor = tty->driver->minor_start + tty->index;
@@ -221,10 +225,11 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
                unsigned icanon)
 {
        struct tty_audit_buf *buf, *buf2;
+       unsigned long flags;
 
        buf = NULL;
        buf2 = NULL;
-       spin_lock_irq(&current->sighand->siglock);
+       spin_lock_irqsave(&current->sighand->siglock, flags);
        if (likely(!current->signal->audit_tty))
                goto out;
        buf = current->signal->tty_audit_buf;
@@ -232,7 +237,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
                atomic_inc(&buf->count);
                goto out;
        }
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
        buf2 = tty_audit_buf_alloc(tty->driver->major,
                                   tty->driver->minor_start + tty->index,
@@ -242,7 +247,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
                return NULL;
        }
 
-       spin_lock_irq(&current->sighand->siglock);
+       spin_lock_irqsave(&current->sighand->siglock, flags);
        if (!current->signal->audit_tty)
                goto out;
        buf = current->signal->tty_audit_buf;
@@ -254,7 +259,7 @@ static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty,
        atomic_inc(&buf->count);
        /* Fall through */
  out:
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_unlock_irqrestore(&current->sighand->siglock, flags);
        if (buf2)
                tty_audit_buf_free(buf2);
        return buf;
@@ -317,16 +322,17 @@ void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
 void tty_audit_push(struct tty_struct *tty)
 {
        struct tty_audit_buf *buf;
+       unsigned long flags;
 
-       spin_lock_irq(&current->sighand->siglock);
+       spin_lock_irqsave(&current->sighand->siglock, flags);
        if (likely(!current->signal->audit_tty)) {
-               spin_unlock_irq(&current->sighand->siglock);
+               spin_unlock_irqrestore(&current->sighand->siglock, flags);
                return;
        }
        buf = current->signal->tty_audit_buf;
        if (buf)
                atomic_inc(&buf->count);
-       spin_unlock_irq(&current->sighand->siglock);
+       spin_unlock_irqrestore(&current->sighand->siglock, flags);
 
        if (buf) {
                int major, minor;
index 44803f2..241aa85 100644 (file)
@@ -804,10 +804,11 @@ 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 = current;
+               unsigned long flags;
 
-               spin_lock_irq(&tsk->sighand->siglock);
+               spin_lock_irqsave(&tsk->sighand->siglock, flags);
                s.enabled = tsk->signal->audit_tty != 0;
-               spin_unlock_irq(&tsk->sighand->siglock);
+               spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
 
                audit_send_reply(NETLINK_CB(skb).portid, seq,
                                 AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
@@ -816,6 +817,7 @@ 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 = current;
+               unsigned long flags;
 
                if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
                        return -EINVAL;
@@ -823,9 +825,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                if (s->enabled != 0 && s->enabled != 1)
                        return -EINVAL;
 
-               spin_lock_irq(&tsk->sighand->siglock);
+               spin_lock_irqsave(&tsk->sighand->siglock, flags);
                tsk->signal->audit_tty = s->enabled != 0;
-               spin_unlock_irq(&tsk->sighand->siglock);
+               spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
                break;
        }
        default: