| Message ID | 20210222150251.12911-1-o.rempel@pengutronix.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [net,v3] net: introduce CAN specific pointer in the struct net_device | expand |
On Mon, 22 Feb 2021 16:02:51 +0100 Oleksij Rempel wrote: > Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using > ml_priv") the CAN framework uses per device specific data in the AF_CAN > protocol. For this purpose the struct net_device->ml_priv is used. Later > the ml_priv usage in CAN was extended for other users, one of them being > CAN_J1939. > > Later in the kernel ml_priv was converted to an union, used by other > drivers. E.g. the tun driver started storing it's stats pointer. > > Since tun devices can claim to be a CAN device, CAN specific protocols > will wrongly interpret this pointer, which will cause system crashes. > Mostly this issue is visible in the CAN_J1939 stack. > > To fix this issue, we request a dedicated CAN pointer within the > net_device struct. > > Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com > Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv") > Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically") > Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") > Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters") > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index ddf4cfc12615..6e25c6f0f190 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1584,6 +1584,16 @@ enum netdev_priv_flags { > #define IFF_L3MDEV_RX_HANDLER IFF_L3MDEV_RX_HANDLER > #define IFF_LIVE_RENAME_OK IFF_LIVE_RENAME_OK > > +/** > + * enum netdev_ml_priv_type - &struct net_device ml_priv_type > + * > + * This enum specifies the type of the struct net_device::ml_priv pointer. > + */ kdoc (scripts/kernel-doc -none include/linux/netdevice.h) is not happy about the fact enum values are not defined. Perhaps they will be sufficiently self-explanatory to not bother documenting? Maybe just: /* Specifies the type of the struct net_device::ml_priv pointer */ ? > +enum netdev_ml_priv_type { > + ML_PRIV_NONE, > + ML_PRIV_CAN, > +}; > + > /** > * struct net_device - The DEVICE structure. > * > @@ -1779,6 +1789,7 @@ enum netdev_priv_flags { > * @nd_net: Network namespace this network device is inside > * > * @ml_priv: Mid-layer private > + @ml_priv_type: Mid-layer private type missing '*' at the start of the line > * @lstats: Loopback statistics > * @tstats: Tunnel statistics > * @dstats: Dummy statistics > @@ -2094,8 +2105,10 @@ struct net_device { > possible_net_t nd_net; > > /* mid-layer private */ > + void *ml_priv; > + enum netdev_ml_priv_type ml_priv_type; > + > union { > - void *ml_priv; > struct pcpu_lstats __percpu *lstats; > struct pcpu_sw_netstats __percpu *tstats; > struct pcpu_dstats __percpu *dstats; > @@ -2286,6 +2299,29 @@ static inline void netdev_reset_rx_headroom(struct net_device *dev) > netdev_set_rx_headroom(dev, -1); > } > > +static inline void *netdev_get_ml_priv(struct net_device *dev, > + enum netdev_ml_priv_type type) > +{ > + if (dev->ml_priv_type != type) > + return NULL; > + > + return dev->ml_priv; > +} > + > +static inline void netdev_set_ml_priv(struct net_device *dev, > + void *ml_priv, > + enum netdev_ml_priv_type type) > +{ > + WARN_ONCE(dev->ml_priv_type && dev->ml_priv_type != type, > + "Overwriting already set ml_priv_type (%u) with different ml_priv_type (%u)!\n", > + dev->ml_priv_type, type); > + WARN_ONCE(!dev->ml_priv_type && dev->ml_priv, > + "Overwriting already set ml_priv and ml_priv_type is ML_PRIV_NONE!\n"); nit: do we need the _ONCE() this helper should be used on control path and relatively rarely, no? > + dev->ml_priv = ml_priv; > + dev->ml_priv_type = type; > +} > + > /* > * Net namespace inlines > */ > @@ -454,6 +455,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) > j1939_local_ecu_put(priv, jsk->addr.src_name, jsk->addr.sa); > } else { > struct net_device *ndev; > + struct can_ml_priv *can_ml; nit: rev xmas tree > > ndev = dev_get_by_index(net, addr->can_ifindex); > if (!ndev) {
Hi Jakub, On Mon, Feb 22, 2021 at 05:30:12PM -0800, Jakub Kicinski wrote: > On Mon, 22 Feb 2021 16:02:51 +0100 Oleksij Rempel wrote: > > Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using > > ml_priv") the CAN framework uses per device specific data in the AF_CAN > > protocol. For this purpose the struct net_device->ml_priv is used. Later > > the ml_priv usage in CAN was extended for other users, one of them being > > CAN_J1939. > > > > Later in the kernel ml_priv was converted to an union, used by other > > drivers. E.g. the tun driver started storing it's stats pointer. > > > > Since tun devices can claim to be a CAN device, CAN specific protocols > > will wrongly interpret this pointer, which will cause system crashes. > > Mostly this issue is visible in the CAN_J1939 stack. > > > > To fix this issue, we request a dedicated CAN pointer within the > > net_device struct. > > > > Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com > > Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv") > > Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically") > > Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") > > Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters") > > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> > > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > > index ddf4cfc12615..6e25c6f0f190 100644 > > --- a/include/linux/netdevice.h > > +++ b/include/linux/netdevice.h > > @@ -1584,6 +1584,16 @@ enum netdev_priv_flags { > > #define IFF_L3MDEV_RX_HANDLER IFF_L3MDEV_RX_HANDLER > > #define IFF_LIVE_RENAME_OK IFF_LIVE_RENAME_OK > > > > +/** > > + * enum netdev_ml_priv_type - &struct net_device ml_priv_type > > + * > > + * This enum specifies the type of the struct net_device::ml_priv pointer. > > + */ > > kdoc (scripts/kernel-doc -none include/linux/netdevice.h) is not happy > about the fact enum values are not defined. Perhaps they will be > sufficiently self-explanatory to not bother documenting? > > Maybe just: > > /* Specifies the type of the struct net_device::ml_priv pointer */ > > ? sounds good, done. > > +enum netdev_ml_priv_type { > > + ML_PRIV_NONE, > > + ML_PRIV_CAN, > > +}; > > + > > /** > > * struct net_device - The DEVICE structure. > > * > > @@ -1779,6 +1789,7 @@ enum netdev_priv_flags { > > * @nd_net: Network namespace this network device is inside > > * > > * @ml_priv: Mid-layer private > > + @ml_priv_type: Mid-layer private type > > missing '*' at the start of the line done > > * @lstats: Loopback statistics > > * @tstats: Tunnel statistics > > * @dstats: Dummy statistics > > @@ -2094,8 +2105,10 @@ struct net_device { > > possible_net_t nd_net; > > > > /* mid-layer private */ > > + void *ml_priv; > > + enum netdev_ml_priv_type ml_priv_type; > > + > > union { > > - void *ml_priv; > > struct pcpu_lstats __percpu *lstats; > > struct pcpu_sw_netstats __percpu *tstats; > > struct pcpu_dstats __percpu *dstats; > > @@ -2286,6 +2299,29 @@ static inline void netdev_reset_rx_headroom(struct net_device *dev) > > netdev_set_rx_headroom(dev, -1); > > } > > > > +static inline void *netdev_get_ml_priv(struct net_device *dev, > > + enum netdev_ml_priv_type type) > > +{ > > + if (dev->ml_priv_type != type) > > + return NULL; > > + > > + return dev->ml_priv; > > +} > > + > > +static inline void netdev_set_ml_priv(struct net_device *dev, > > + void *ml_priv, > > + enum netdev_ml_priv_type type) > > +{ > > + WARN_ONCE(dev->ml_priv_type && dev->ml_priv_type != type, > > + "Overwriting already set ml_priv_type (%u) with different ml_priv_type (%u)!\n", > > + dev->ml_priv_type, type); > > + WARN_ONCE(!dev->ml_priv_type && dev->ml_priv, > > + "Overwriting already set ml_priv and ml_priv_type is ML_PRIV_NONE!\n"); > > nit: do we need the _ONCE() this helper should be used on control path > and relatively rarely, no? I have no strong opinion right now. Changed to WARN() > > + dev->ml_priv = ml_priv; > > + dev->ml_priv_type = type; > > +} > > + > > /* > > * Net namespace inlines > > */ > > > @@ -454,6 +455,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) > > j1939_local_ecu_put(priv, jsk->addr.src_name, jsk->addr.sa); > > } else { > > struct net_device *ndev; > > + struct can_ml_priv *can_ml; > > nit: rev xmas treei done > > > > > ndev = dev_get_by_index(net, addr->can_ifindex); > > if (!ndev) { > Thank you, Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c index d9281ae853f8..311d8564d611 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -239,6 +239,7 @@ void can_setup(struct net_device *dev) struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max, unsigned int txqs, unsigned int rxqs) { + struct can_ml_priv *can_ml; struct net_device *dev; struct can_priv *priv; int size; @@ -270,7 +271,8 @@ struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max, priv = netdev_priv(dev); priv->dev = dev; - dev->ml_priv = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN); + can_ml = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN); + can_set_ml_priv(dev, can_ml); if (echo_skb_max) { priv->echo_skb_max = echo_skb_max; diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c index a1bd1be09548..30c8d53c9745 100644 --- a/drivers/net/can/slcan.c +++ b/drivers/net/can/slcan.c @@ -516,6 +516,7 @@ static struct slcan *slc_alloc(void) int i; char name[IFNAMSIZ]; struct net_device *dev = NULL; + struct can_ml_priv *can_ml; struct slcan *sl; int size; @@ -538,7 +539,8 @@ static struct slcan *slc_alloc(void) dev->base_addr = i; sl = netdev_priv(dev); - dev->ml_priv = (void *)sl + ALIGN(sizeof(*sl), NETDEV_ALIGN); + can_ml = (void *)sl + ALIGN(sizeof(*sl), NETDEV_ALIGN); + can_set_ml_priv(dev, can_ml); /* Initialize channel control data */ sl->magic = SLCAN_MAGIC; diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c index 39ca14b0585d..067705e2850b 100644 --- a/drivers/net/can/vcan.c +++ b/drivers/net/can/vcan.c @@ -153,7 +153,7 @@ static void vcan_setup(struct net_device *dev) dev->addr_len = 0; dev->tx_queue_len = 0; dev->flags = IFF_NOARP; - dev->ml_priv = netdev_priv(dev); + can_set_ml_priv(dev, netdev_priv(dev)); /* set flags according to driver capabilities */ if (echo) diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c index f9a524c5f6d6..8861a7d875e7 100644 --- a/drivers/net/can/vxcan.c +++ b/drivers/net/can/vxcan.c @@ -141,6 +141,8 @@ static const struct net_device_ops vxcan_netdev_ops = { static void vxcan_setup(struct net_device *dev) { + struct can_ml_priv *can_ml; + dev->type = ARPHRD_CAN; dev->mtu = CANFD_MTU; dev->hard_header_len = 0; @@ -149,7 +151,9 @@ static void vxcan_setup(struct net_device *dev) dev->flags = (IFF_NOARP|IFF_ECHO); dev->netdev_ops = &vxcan_netdev_ops; dev->needs_free_netdev = true; - dev->ml_priv = netdev_priv(dev) + ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN); + + can_ml = netdev_priv(dev) + ALIGN(sizeof(struct vxcan_priv), NETDEV_ALIGN); + can_set_ml_priv(dev, can_ml); } /* forward declaration for rtnl_create_link() */ diff --git a/include/linux/can/can-ml.h b/include/linux/can/can-ml.h index 2f5d731ae251..8afa92d15a66 100644 --- a/include/linux/can/can-ml.h +++ b/include/linux/can/can-ml.h @@ -44,6 +44,7 @@ #include <linux/can.h> #include <linux/list.h> +#include <linux/netdevice.h> #define CAN_SFF_RCV_ARRAY_SZ (1 << CAN_SFF_ID_BITS) #define CAN_EFF_RCV_HASH_BITS 10 @@ -65,4 +66,15 @@ struct can_ml_priv { #endif }; +static inline struct can_ml_priv *can_get_ml_priv(struct net_device *dev) +{ + return netdev_get_ml_priv(dev, ML_PRIV_CAN); +} + +static inline void can_set_ml_priv(struct net_device *dev, + struct can_ml_priv *ml_priv) +{ + netdev_set_ml_priv(dev, ml_priv, ML_PRIV_CAN); +} + #endif /* CAN_ML_H */ diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index ddf4cfc12615..6e25c6f0f190 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1584,6 +1584,16 @@ enum netdev_priv_flags { #define IFF_L3MDEV_RX_HANDLER IFF_L3MDEV_RX_HANDLER #define IFF_LIVE_RENAME_OK IFF_LIVE_RENAME_OK +/** + * enum netdev_ml_priv_type - &struct net_device ml_priv_type + * + * This enum specifies the type of the struct net_device::ml_priv pointer. + */ +enum netdev_ml_priv_type { + ML_PRIV_NONE, + ML_PRIV_CAN, +}; + /** * struct net_device - The DEVICE structure. * @@ -1779,6 +1789,7 @@ enum netdev_priv_flags { * @nd_net: Network namespace this network device is inside * * @ml_priv: Mid-layer private + @ml_priv_type: Mid-layer private type * @lstats: Loopback statistics * @tstats: Tunnel statistics * @dstats: Dummy statistics @@ -2094,8 +2105,10 @@ struct net_device { possible_net_t nd_net; /* mid-layer private */ + void *ml_priv; + enum netdev_ml_priv_type ml_priv_type; + union { - void *ml_priv; struct pcpu_lstats __percpu *lstats; struct pcpu_sw_netstats __percpu *tstats; struct pcpu_dstats __percpu *dstats; @@ -2286,6 +2299,29 @@ static inline void netdev_reset_rx_headroom(struct net_device *dev) netdev_set_rx_headroom(dev, -1); } +static inline void *netdev_get_ml_priv(struct net_device *dev, + enum netdev_ml_priv_type type) +{ + if (dev->ml_priv_type != type) + return NULL; + + return dev->ml_priv; +} + +static inline void netdev_set_ml_priv(struct net_device *dev, + void *ml_priv, + enum netdev_ml_priv_type type) +{ + WARN_ONCE(dev->ml_priv_type && dev->ml_priv_type != type, + "Overwriting already set ml_priv_type (%u) with different ml_priv_type (%u)!\n", + dev->ml_priv_type, type); + WARN_ONCE(!dev->ml_priv_type && dev->ml_priv, + "Overwriting already set ml_priv and ml_priv_type is ML_PRIV_NONE!\n"); + + dev->ml_priv = ml_priv; + dev->ml_priv_type = type; +} + /* * Net namespace inlines */ diff --git a/net/can/af_can.c b/net/can/af_can.c index 837bb8af0ec3..cce2af10eb3e 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -304,8 +304,8 @@ static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net, struct net_device *dev) { if (dev) { - struct can_ml_priv *ml_priv = dev->ml_priv; - return &ml_priv->dev_rcv_lists; + struct can_ml_priv *can_ml = can_get_ml_priv(dev); + return &can_ml->dev_rcv_lists; } else { return net->can.rx_alldev_list; } @@ -790,25 +790,6 @@ void can_proto_unregister(const struct can_proto *cp) } EXPORT_SYMBOL(can_proto_unregister); -/* af_can notifier to create/remove CAN netdevice specific structs */ -static int can_notifier(struct notifier_block *nb, unsigned long msg, - void *ptr) -{ - struct net_device *dev = netdev_notifier_info_to_dev(ptr); - - if (dev->type != ARPHRD_CAN) - return NOTIFY_DONE; - - switch (msg) { - case NETDEV_REGISTER: - WARN(!dev->ml_priv, - "No CAN mid layer private allocated, please fix your driver and use alloc_candev()!\n"); - break; - } - - return NOTIFY_DONE; -} - static int can_pernet_init(struct net *net) { spin_lock_init(&net->can.rcvlists_lock); @@ -876,11 +857,6 @@ static const struct net_proto_family can_family_ops = { .owner = THIS_MODULE, }; -/* notifier block for netdevice event */ -static struct notifier_block can_netdev_notifier __read_mostly = { - .notifier_call = can_notifier, -}; - static struct pernet_operations can_pernet_ops __read_mostly = { .init = can_pernet_init, .exit = can_pernet_exit, @@ -911,17 +887,12 @@ static __init int can_init(void) err = sock_register(&can_family_ops); if (err) goto out_sock; - err = register_netdevice_notifier(&can_netdev_notifier); - if (err) - goto out_notifier; dev_add_pack(&can_packet); dev_add_pack(&canfd_packet); return 0; -out_notifier: - sock_unregister(PF_CAN); out_sock: unregister_pernet_subsys(&can_pernet_ops); out_pernet: @@ -935,7 +906,6 @@ static __exit void can_exit(void) /* protocol unregister */ dev_remove_pack(&canfd_packet); dev_remove_pack(&can_packet); - unregister_netdevice_notifier(&can_netdev_notifier); sock_unregister(PF_CAN); unregister_pernet_subsys(&can_pernet_ops); diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index bb914d8b4216..da3a7a7bcff2 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -140,9 +140,9 @@ static struct j1939_priv *j1939_priv_create(struct net_device *ndev) static inline void j1939_priv_set(struct net_device *ndev, struct j1939_priv *priv) { - struct can_ml_priv *can_ml_priv = ndev->ml_priv; + struct can_ml_priv *can_ml = can_get_ml_priv(ndev); - can_ml_priv->j1939_priv = priv; + can_ml->j1939_priv = priv; } static void __j1939_priv_release(struct kref *kref) @@ -211,12 +211,9 @@ static void __j1939_rx_release(struct kref *kref) /* get pointer to priv without increasing ref counter */ static inline struct j1939_priv *j1939_ndev_to_priv(struct net_device *ndev) { - struct can_ml_priv *can_ml_priv = ndev->ml_priv; + struct can_ml_priv *can_ml = can_get_ml_priv(ndev); - if (!can_ml_priv) - return NULL; - - return can_ml_priv->j1939_priv; + return can_ml->j1939_priv; } static struct j1939_priv *j1939_priv_get_by_ndev_locked(struct net_device *ndev) @@ -225,9 +222,6 @@ static struct j1939_priv *j1939_priv_get_by_ndev_locked(struct net_device *ndev) lockdep_assert_held(&j1939_netdev_lock); - if (ndev->type != ARPHRD_CAN) - return NULL; - priv = j1939_ndev_to_priv(ndev); if (priv) j1939_priv_get(priv); @@ -348,15 +342,16 @@ static int j1939_netdev_notify(struct notifier_block *nb, unsigned long msg, void *data) { struct net_device *ndev = netdev_notifier_info_to_dev(data); + struct can_ml_priv *can_ml = can_get_ml_priv(ndev); struct j1939_priv *priv; + if (!can_ml) + goto notify_done; + priv = j1939_priv_get_by_ndev(ndev); if (!priv) goto notify_done; - if (ndev->type != ARPHRD_CAN) - goto notify_put; - switch (msg) { case NETDEV_DOWN: j1939_cancel_active_session(priv, NULL); @@ -365,7 +360,6 @@ static int j1939_netdev_notify(struct notifier_block *nb, break; } -notify_put: j1939_priv_put(priv); notify_done: diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index f23966526a88..4e4a510d82f9 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -12,6 +12,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/can/can-ml.h> #include <linux/can/core.h> #include <linux/can/skb.h> #include <linux/errqueue.h> @@ -454,6 +455,7 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) j1939_local_ecu_put(priv, jsk->addr.src_name, jsk->addr.sa); } else { struct net_device *ndev; + struct can_ml_priv *can_ml; ndev = dev_get_by_index(net, addr->can_ifindex); if (!ndev) { @@ -461,15 +463,8 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) goto out_release_sock; } - if (ndev->type != ARPHRD_CAN) { - dev_put(ndev); - ret = -ENODEV; - goto out_release_sock; - } - - if (!ndev->ml_priv) { - netdev_warn_once(ndev, - "No CAN mid layer private allocated, please fix your driver and use alloc_candev()!\n"); + can_ml = can_get_ml_priv(ndev); + if (!can_ml) { dev_put(ndev); ret = -ENODEV; goto out_release_sock; diff --git a/net/can/proc.c b/net/can/proc.c index 5ea8695f507e..b15760b5c1cc 100644 --- a/net/can/proc.c +++ b/net/can/proc.c @@ -322,8 +322,11 @@ static int can_rcvlist_proc_show(struct seq_file *m, void *v) /* receive list for registered CAN devices */ for_each_netdev_rcu(net, dev) { - if (dev->type == ARPHRD_CAN && dev->ml_priv) - can_rcvlist_proc_show_one(m, idx, dev, dev->ml_priv); + struct can_ml_priv *can_ml = can_get_ml_priv(dev); + + if (can_ml) + can_rcvlist_proc_show_one(m, idx, dev, + &can_ml->dev_rcv_lists); } rcu_read_unlock(); @@ -375,8 +378,10 @@ static int can_rcvlist_sff_proc_show(struct seq_file *m, void *v) /* sff receive list for registered CAN devices */ for_each_netdev_rcu(net, dev) { - if (dev->type == ARPHRD_CAN && dev->ml_priv) { - dev_rcv_lists = dev->ml_priv; + struct can_ml_priv *can_ml = can_get_ml_priv(dev); + + if (can_ml) { + dev_rcv_lists = &can_ml->dev_rcv_lists; can_rcvlist_proc_show_array(m, dev, dev_rcv_lists->rx_sff, ARRAY_SIZE(dev_rcv_lists->rx_sff)); } @@ -406,8 +411,10 @@ static int can_rcvlist_eff_proc_show(struct seq_file *m, void *v) /* eff receive list for registered CAN devices */ for_each_netdev_rcu(net, dev) { - if (dev->type == ARPHRD_CAN && dev->ml_priv) { - dev_rcv_lists = dev->ml_priv; + struct can_ml_priv *can_ml = can_get_ml_priv(dev); + + if (can_ml) { + dev_rcv_lists = &can_ml->dev_rcv_lists; can_rcvlist_proc_show_array(m, dev, dev_rcv_lists->rx_eff, ARRAY_SIZE(dev_rcv_lists->rx_eff)); }
Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv") the CAN framework uses per device specific data in the AF_CAN protocol. For this purpose the struct net_device->ml_priv is used. Later the ml_priv usage in CAN was extended for other users, one of them being CAN_J1939. Later in the kernel ml_priv was converted to an union, used by other drivers. E.g. the tun driver started storing it's stats pointer. Since tun devices can claim to be a CAN device, CAN specific protocols will wrongly interpret this pointer, which will cause system crashes. Mostly this issue is visible in the CAN_J1939 stack. To fix this issue, we request a dedicated CAN pointer within the net_device struct. Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv") Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically") Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters") Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- drivers/net/can/dev/dev.c | 4 +++- drivers/net/can/slcan.c | 4 +++- drivers/net/can/vcan.c | 2 +- drivers/net/can/vxcan.c | 6 +++++- include/linux/can/can-ml.h | 12 ++++++++++++ include/linux/netdevice.h | 38 +++++++++++++++++++++++++++++++++++++- net/can/af_can.c | 34 ++-------------------------------- net/can/j1939/main.c | 22 ++++++++-------------- net/can/j1939/socket.c | 13 ++++--------- net/can/proc.c | 19 +++++++++++++------ 10 files changed, 88 insertions(+), 66 deletions(-)