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Diffstat (limited to 'net/can/isotp.c')
-rw-r--r--net/can/isotp.c29
1 files changed, 22 insertions, 7 deletions
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 02cbcb2ecf0d..d2a430b6a13b 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -56,6 +56,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
+#include <linux/spinlock.h>
#include <linux/hrtimer.h>
#include <linux/wait.h>
#include <linux/uio.h>
@@ -145,6 +146,7 @@ struct isotp_sock {
struct tpcon rx, tx;
struct list_head notifier;
wait_queue_head_t wait;
+ spinlock_t rx_lock; /* protect single thread state machine */
};
static LIST_HEAD(isotp_notifier_list);
@@ -615,11 +617,17 @@ static void isotp_rcv(struct sk_buff *skb, void *data)
n_pci_type = cf->data[ae] & 0xF0;
+ /* Make sure the state changes and data structures stay consistent at
+ * CAN frame reception time. This locking is not needed in real world
+ * use cases but the inconsistency can be triggered with syzkaller.
+ */
+ spin_lock(&so->rx_lock);
+
if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
/* check rx/tx path half duplex expectations */
if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
(so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
- return;
+ goto out_unlock;
}
switch (n_pci_type) {
@@ -668,6 +676,9 @@ static void isotp_rcv(struct sk_buff *skb, void *data)
isotp_rcv_cf(sk, cf, ae, skb);
break;
}
+
+out_unlock:
+ spin_unlock(&so->rx_lock);
}
static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
@@ -876,7 +887,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if (!size || size > MAX_MSG_LENGTH) {
err = -EINVAL;
- goto err_out;
+ goto err_out_drop;
}
/* take care of a potential SF_DL ESC offset for TX_DL > 8 */
@@ -886,24 +897,24 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) &&
(size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
err = -EINVAL;
- goto err_out;
+ goto err_out_drop;
}
err = memcpy_from_msg(so->tx.buf, msg, size);
if (err < 0)
- goto err_out;
+ goto err_out_drop;
dev = dev_get_by_index(sock_net(sk), so->ifindex);
if (!dev) {
err = -ENXIO;
- goto err_out;
+ goto err_out_drop;
}
skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
msg->msg_flags & MSG_DONTWAIT, &err);
if (!skb) {
dev_put(dev);
- goto err_out;
+ goto err_out_drop;
}
can_skb_reserve(skb);
@@ -965,7 +976,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if (err) {
pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
__func__, ERR_PTR(err));
- goto err_out;
+ goto err_out_drop;
}
if (wait_tx_done) {
@@ -978,6 +989,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
return size;
+err_out_drop:
+ /* drop this PDU and unlock a potential wait queue */
+ old_state = ISOTP_IDLE;
err_out:
so->tx.state = old_state;
if (so->tx.state == ISOTP_IDLE)
@@ -1444,6 +1458,7 @@ static int isotp_init(struct sock *sk)
so->txtimer.function = isotp_tx_timer_handler;
init_waitqueue_head(&so->wait);
+ spin_lock_init(&so->rx_lock);
spin_lock(&isotp_notifier_lock);
list_add_tail(&so->notifier, &isotp_notifier_list);