From bde02ca858448cf54a4226774dd1481f3bcc455e Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 30 Apr 2013 11:01:14 -0400 Subject: [PATCH] audit: use spin_lock_irqsave/restore in audit tty code 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 --- drivers/tty/tty_audit.c | 32 +++++++++++++++++++------------- kernel/audit.c | 10 ++++++---- 2 files changed, 25 insertions(+), 17 deletions(-) diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c index ea2e5ad7173..755d418019c 100644 --- a/drivers/tty/tty_audit.c +++ b/drivers/tty/tty_audit.c @@ -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(¤t->sighand->siglock); + spin_lock_irqsave(¤t->sighand->siglock, flags); buf = current->signal->tty_audit_buf; current->signal->tty_audit_buf = NULL; - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->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(¤t->sighand->siglock); + unsigned long flags; + + spin_lock_irqsave(¤t->sighand->siglock, flags); sig->audit_tty = current->signal->audit_tty; - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->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(¤t->sighand->siglock); + spin_lock_irqsave(¤t->sighand->siglock, flags); should_audit = current->signal->audit_tty; buf = current->signal->tty_audit_buf; if (buf) atomic_inc(&buf->count); - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->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(¤t->sighand->siglock); + spin_lock_irqsave(¤t->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(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->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(¤t->sighand->siglock); + spin_lock_irqsave(¤t->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(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->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(¤t->sighand->siglock); + spin_lock_irqsave(¤t->sighand->siglock, flags); if (likely(!current->signal->audit_tty)) { - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); return; } buf = current->signal->tty_audit_buf; if (buf) atomic_inc(&buf->count); - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); if (buf) { int major, minor; diff --git a/kernel/audit.c b/kernel/audit.c index 44803f25b23..241aa8593fa 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -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: -- 2.43.2