From: Oliver Hartkopp Commit 4e096a18867a ("net: introduce CAN specific pointer in the struct net_device") introduced an explicit way to assign the midlayer private pointer (dev->ml_priv) to named users like ML_PRIV_CAN. A valid pointer returned by can_get_ml_priv() therefore identifies a real CAN device. The referenced commit only converted the j1939 and proc code to this check, while the other parts of the CAN subsystem still rely on dev->type == ARPHRD_CAN. The TUNSETLINK ioctl allows a down TUN/TAP device to set its hardware type to ARPHRD_CAN while dev->ml_priv remains NULL. Such a repurposed netdevice passes the ARPHRD_CAN checks and triggers a NULL pointer dereference when CAN filters are created and when they are removed, e.g. by the CAN protocols' netdevice notifier handlers. This only requires owning a TUN/TAP device or CAP_NET_ADMIN in an unprivileged user namespace. Convert the remaining ARPHRD_CAN checks in af_can, bcm, gw, isotp and raw to can_get_ml_priv(). Fixes: 4e096a18867a ("net: introduce CAN specific pointer in the struct net_device") Cc: stable@kernel.org Cc: Oleksij Rempel Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20261012164802.94113-1-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde --- net/can/af_can.c | 15 ++++++--------- net/can/bcm.c | 7 ++++--- net/can/gw.c | 7 ++++--- net/can/isotp.c | 5 +++-- net/can/raw.c | 4 ++-- 5 files changed, 19 insertions(+), 19 deletions(-) diff --git a/net/can/af_can.c b/net/can/af_can.c index 34fe3b28d576..dc27ace43719 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -226,7 +226,7 @@ int can_send(struct sk_buff *skb, int loop) goto inval_skb; } - if (unlikely(skb->dev->type != ARPHRD_CAN)) { + if (unlikely(!can_get_ml_priv(skb->dev))) { err = -EPERM; goto inval_skb; } @@ -452,7 +452,7 @@ int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id, /* insert new receiver (dev,canid,mask) -> (func,data) */ - if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev))) + if (dev && !can_get_ml_priv(dev)) return -ENODEV; if (dev && !net_eq(net, dev_net(dev))) @@ -519,7 +519,7 @@ void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; struct can_dev_rcv_lists *dev_rcv_lists; - if (dev && dev->type != ARPHRD_CAN) + if (dev && !can_get_ml_priv(dev)) return; if (dev && !net_eq(net, dev_net(dev))) @@ -684,8 +684,7 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev, { struct can_skb_ext *csx = can_skb_ext_find(skb); - if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || - !csx || !can_is_can_skb(skb))) { + if (unlikely(!can_get_ml_priv(dev) || !csx || !can_is_can_skb(skb))) { pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n", dev->type, skb->len); @@ -710,8 +709,7 @@ static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, { struct can_skb_ext *csx = can_skb_ext_find(skb); - if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || - !csx || !can_is_canfd_skb(skb))) { + if (unlikely(!can_get_ml_priv(dev) || !csx || !can_is_canfd_skb(skb))) { pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n", dev->type, skb->len); @@ -736,8 +734,7 @@ static int canxl_rcv(struct sk_buff *skb, struct net_device *dev, { struct can_skb_ext *csx = can_skb_ext_find(skb); - if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || - !csx || !can_is_canxl_skb(skb))) { + if (unlikely(!can_get_ml_priv(dev) || !csx || !can_is_canxl_skb(skb))) { pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n", dev->type, skb->len); diff --git a/net/can/bcm.c b/net/can/bcm.c index 3d637a1e0ac1..60406439a13f 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -54,6 +54,7 @@ #include #include #include +#include #include #include #include @@ -1719,7 +1720,7 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) goto out_release; } - if (dev->type != ARPHRD_CAN) { + if (!can_get_ml_priv(dev)) { dev_put(dev); ret = -ENODEV; goto out_release; @@ -1867,7 +1868,7 @@ static int bcm_notifier(struct notifier_block *nb, unsigned long msg, { struct net_device *dev = netdev_notifier_info_to_dev(ptr); - if (dev->type != ARPHRD_CAN) + if (!can_get_ml_priv(dev)) return NOTIFY_DONE; if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN) return NOTIFY_DONE; @@ -2024,7 +2025,7 @@ static int bcm_connect(struct socket *sock, struct sockaddr_unsized *uaddr, int ret = -ENODEV; goto fail; } - if (dev->type != ARPHRD_CAN) { + if (!can_get_ml_priv(dev)) { dev_put(dev); ret = -ENODEV; goto fail; diff --git a/net/can/gw.c b/net/can/gw.c index 5793cb2420ed..54bb5bd3242a 100644 --- a/net/can/gw.c +++ b/net/can/gw.c @@ -52,6 +52,7 @@ #include #include #include +#include #include #include #include @@ -612,7 +613,7 @@ static int cgw_notifier(struct notifier_block *nb, struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct net *net = dev_net(dev); - if (dev->type != ARPHRD_CAN) + if (!can_get_ml_priv(dev)) return NOTIFY_DONE; if (msg == NETDEV_UNREGISTER) { @@ -1163,7 +1164,7 @@ static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh, if (!gwj->src.dev) goto out; - if (gwj->src.dev->type != ARPHRD_CAN) + if (!can_get_ml_priv(gwj->src.dev)) goto out; gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx); @@ -1171,7 +1172,7 @@ static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh, if (!gwj->dst.dev) goto out; - if (gwj->dst.dev->type != ARPHRD_CAN) + if (!can_get_ml_priv(gwj->dst.dev)) goto out; /* is sending the skb back to the incoming interface intended? */ diff --git a/net/can/isotp.c b/net/can/isotp.c index f5dc9d04bd68..6c28802c0605 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -65,6 +65,7 @@ #include #include #include +#include #include #include #include @@ -1610,7 +1611,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int l err = -ENODEV; goto out; } - if (dev->type != ARPHRD_CAN) { + if (!can_get_ml_priv(dev)) { err = -ENODEV; goto out_put_dev; } @@ -1897,7 +1898,7 @@ static int isotp_notifier(struct notifier_block *nb, unsigned long msg, { struct net_device *dev = netdev_notifier_info_to_dev(ptr); - if (dev->type != ARPHRD_CAN) + if (!can_get_ml_priv(dev)) return NOTIFY_DONE; if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN) return NOTIFY_DONE; diff --git a/net/can/raw.c b/net/can/raw.c index 6944ebab3feb..ad611906b308 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -348,7 +348,7 @@ static int raw_notifier(struct notifier_block *nb, unsigned long msg, { struct net_device *dev = netdev_notifier_info_to_dev(ptr); - if (dev->type != ARPHRD_CAN) + if (!can_get_ml_priv(dev)) return NOTIFY_DONE; if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN) return NOTIFY_DONE; @@ -491,7 +491,7 @@ static int raw_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int len err = -ENODEV; goto out; } - if (dev->type != ARPHRD_CAN) { + if (!can_get_ml_priv(dev)) { err = -ENODEV; goto out_put_dev; } -- 2.53.0