From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/net/wan/lapbether.c | 537 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 537 insertions(+) create mode 100644 drivers/net/wan/lapbether.c (limited to 'drivers/net/wan/lapbether.c') diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c new file mode 100644 index 000000000..c3630a829 --- /dev/null +++ b/drivers/net/wan/lapbether.c @@ -0,0 +1,537 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * "LAPB via ethernet" driver release 001 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * This is a "pseudo" network driver to allow LAPB over Ethernet. + * + * This driver can use any ethernet destination address, and can be + * limited to accept frames from one dedicated ethernet card only. + * + * History + * LAPBETH 001 Jonathan Naylor Cloned from bpqether.c + * 2000-10-29 Henner Eisen lapb_data_indication() return status. + * 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; + +/* If this number is made larger, check that the temporary string buffer + * in lapbeth_new_device is large enough to store the probe device name. + */ +#define MAXLAPBDEV 100 + +struct lapbethdev { + struct list_head node; + struct net_device *ethdev; /* link to ethernet device */ + struct net_device *axdev; /* lapbeth device (lapb#) */ + bool up; + spinlock_t up_lock; /* Protects "up" */ + struct sk_buff_head rx_queue; + struct napi_struct napi; +}; + +static LIST_HEAD(lapbeth_devices); + +static void lapbeth_connected(struct net_device *dev, int reason); +static void lapbeth_disconnected(struct net_device *dev, int reason); + +/* ------------------------------------------------------------------------ */ + +/* Get the LAPB device for the ethernet device + */ +static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) +{ + struct lapbethdev *lapbeth; + + list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node, lockdep_rtnl_is_held()) { + if (lapbeth->ethdev == dev) + return lapbeth; + } + return NULL; +} + +static __inline__ int dev_is_ethdev(struct net_device *dev) +{ + return dev->type == ARPHRD_ETHER && !netdev_need_ops_lock(dev); +} + +/* ------------------------------------------------------------------------ */ + +static int lapbeth_napi_poll(struct napi_struct *napi, int budget) +{ + struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev, + napi); + struct sk_buff *skb; + int processed = 0; + + for (; processed < budget; ++processed) { + skb = skb_dequeue(&lapbeth->rx_queue); + if (!skb) + break; + netif_receive_skb_core(skb); + } + + if (processed < budget) + napi_complete(napi); + + return processed; +} + +/* Receive a LAPB frame via an ethernet interface. + */ +static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, + struct packet_type *ptype, struct net_device *orig_dev) +{ + int len, err; + struct lapbethdev *lapbeth; + + if (dev_net(dev) != &init_net) + goto drop; + + skb = skb_share_check(skb, GFP_ATOMIC); + if (!skb) + return NET_RX_DROP; + + if (!pskb_may_pull(skb, 2)) + goto drop; + + rcu_read_lock(); + lapbeth = lapbeth_get_x25_dev(dev); + if (!lapbeth) + goto drop_unlock_rcu; + spin_lock_bh(&lapbeth->up_lock); + if (!lapbeth->up) + goto drop_unlock; + + len = skb->data[0] + skb->data[1] * 256; + dev->stats.rx_packets++; + dev->stats.rx_bytes += len; + + skb_pull(skb, 2); /* Remove the length bytes */ + skb_trim(skb, len); /* Set the length of the data */ + + err = lapb_data_received(lapbeth->axdev, skb); + if (err != LAPB_OK) { + printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); + goto drop_unlock; + } +out: + spin_unlock_bh(&lapbeth->up_lock); + rcu_read_unlock(); + return 0; +drop_unlock: + kfree_skb(skb); + goto out; +drop_unlock_rcu: + rcu_read_unlock(); +drop: + kfree_skb(skb); + return 0; +} + +static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) +{ + struct lapbethdev *lapbeth = netdev_priv(dev); + unsigned char *ptr; + + if (skb_cow(skb, 1)) { + kfree_skb(skb); + return NET_RX_DROP; + } + + skb_push(skb, 1); + + ptr = skb->data; + *ptr = X25_IFACE_DATA; + + skb->protocol = x25_type_trans(skb, dev); + + skb_queue_tail(&lapbeth->rx_queue, skb); + napi_schedule(&lapbeth->napi); + return NET_RX_SUCCESS; +} + +/* Send a LAPB frame via an ethernet interface + */ +static netdev_tx_t lapbeth_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct lapbethdev *lapbeth = netdev_priv(dev); + int err; + + spin_lock_bh(&lapbeth->up_lock); + if (!lapbeth->up) + goto drop; + + /* There should be a pseudo header of 1 byte added by upper layers. + * Check to make sure it is there before reading it. + */ + if (skb->len < 1) + goto drop; + + switch (skb->data[0]) { + case X25_IFACE_DATA: + break; + case X25_IFACE_CONNECT: + err = lapb_connect_request(dev); + if (err == LAPB_CONNECTED) + lapbeth_connected(dev, LAPB_OK); + else if (err != LAPB_OK) + pr_err("lapb_connect_request error: %d\n", err); + goto drop; + case X25_IFACE_DISCONNECT: + err = lapb_disconnect_request(dev); + if (err == LAPB_NOTCONNECTED) + lapbeth_disconnected(dev, LAPB_OK); + else if (err != LAPB_OK) + pr_err("lapb_disconnect_request err: %d\n", err); + fallthrough; + default: + goto drop; + } + + skb_pull(skb, 1); + + err = lapb_data_request(dev, skb); + if (err != LAPB_OK) { + pr_err("lapb_data_request error - %d\n", err); + goto drop; + } +out: + spin_unlock_bh(&lapbeth->up_lock); + return NETDEV_TX_OK; +drop: + kfree_skb(skb); + goto out; +} + +static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) +{ + struct lapbethdev *lapbeth = netdev_priv(ndev); + unsigned char *ptr; + struct net_device *dev; + int size = skb->len; + + ptr = skb_push(skb, 2); + + *ptr++ = size % 256; + *ptr++ = size / 256; + + ndev->stats.tx_packets++; + ndev->stats.tx_bytes += size; + + skb->dev = dev = lapbeth->ethdev; + + skb->protocol = htons(ETH_P_DEC); + + skb_reset_network_header(skb); + + dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); + + dev_queue_xmit(skb); +} + +static void lapbeth_connected(struct net_device *dev, int reason) +{ + struct lapbethdev *lapbeth = netdev_priv(dev); + unsigned char *ptr; + struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); + + if (!skb) + return; + + ptr = skb_put(skb, 1); + *ptr = X25_IFACE_CONNECT; + + skb->protocol = x25_type_trans(skb, dev); + + skb_queue_tail(&lapbeth->rx_queue, skb); + napi_schedule(&lapbeth->napi); +} + +static void lapbeth_disconnected(struct net_device *dev, int reason) +{ + struct lapbethdev *lapbeth = netdev_priv(dev); + unsigned char *ptr; + struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC); + + if (!skb) + return; + + ptr = skb_put(skb, 1); + *ptr = X25_IFACE_DISCONNECT; + + skb->protocol = x25_type_trans(skb, dev); + + skb_queue_tail(&lapbeth->rx_queue, skb); + napi_schedule(&lapbeth->napi); +} + +/* Set AX.25 callsign + */ +static int lapbeth_set_mac_address(struct net_device *dev, void *addr) +{ + struct sockaddr *sa = addr; + + dev_addr_set(dev, sa->sa_data); + return 0; +} + +static const struct lapb_register_struct lapbeth_callbacks = { + .connect_confirmation = lapbeth_connected, + .connect_indication = lapbeth_connected, + .disconnect_confirmation = lapbeth_disconnected, + .disconnect_indication = lapbeth_disconnected, + .data_indication = lapbeth_data_indication, + .data_transmit = lapbeth_data_transmit, +}; + +/* open/close a device + */ +static int lapbeth_open(struct net_device *dev) +{ + struct lapbethdev *lapbeth = netdev_priv(dev); + int err; + + napi_enable(&lapbeth->napi); + + err = lapb_register(dev, &lapbeth_callbacks); + if (err != LAPB_OK) { + napi_disable(&lapbeth->napi); + pr_err("lapb_register error: %d\n", err); + return -ENODEV; + } + + spin_lock_bh(&lapbeth->up_lock); + lapbeth->up = true; + spin_unlock_bh(&lapbeth->up_lock); + + return 0; +} + +static int lapbeth_close(struct net_device *dev) +{ + struct lapbethdev *lapbeth = netdev_priv(dev); + int err; + + spin_lock_bh(&lapbeth->up_lock); + lapbeth->up = false; + spin_unlock_bh(&lapbeth->up_lock); + + err = lapb_unregister(dev); + if (err != LAPB_OK) + pr_err("lapb_unregister error: %d\n", err); + + napi_disable(&lapbeth->napi); + + return 0; +} + +/* ------------------------------------------------------------------------ */ + +static const struct net_device_ops lapbeth_netdev_ops = { + .ndo_open = lapbeth_open, + .ndo_stop = lapbeth_close, + .ndo_start_xmit = lapbeth_xmit, + .ndo_set_mac_address = lapbeth_set_mac_address, +}; + +static void lapbeth_setup(struct net_device *dev) +{ + netdev_lockdep_set_classes(dev); + dev->netdev_ops = &lapbeth_netdev_ops; + dev->needs_free_netdev = true; + dev->type = ARPHRD_X25; + dev->hard_header_len = 0; + dev->mtu = 1000; + dev->addr_len = 0; +} + +/* Setup a new device. + */ +static int lapbeth_new_device(struct net_device *dev) +{ + struct net_device *ndev; + struct lapbethdev *lapbeth; + int rc = -ENOMEM; + + ASSERT_RTNL(); + + if (dev->type != ARPHRD_ETHER) + return -EINVAL; + + ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN, + lapbeth_setup); + if (!ndev) + goto out; + + /* When transmitting data: + * first this driver removes a pseudo header of 1 byte, + * then the lapb module prepends an LAPB header of at most 3 bytes, + * then this driver prepends a length field of 2 bytes, + * then the underlying Ethernet device prepends its own header. + */ + ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len + + dev->needed_headroom; + ndev->needed_tailroom = dev->needed_tailroom; + + lapbeth = netdev_priv(ndev); + lapbeth->axdev = ndev; + + dev_hold(dev); + lapbeth->ethdev = dev; + + lapbeth->up = false; + spin_lock_init(&lapbeth->up_lock); + + skb_queue_head_init(&lapbeth->rx_queue); + netif_napi_add_weight(ndev, &lapbeth->napi, lapbeth_napi_poll, 16); + + rc = -EIO; + if (register_netdevice(ndev)) + goto fail; + + list_add_rcu(&lapbeth->node, &lapbeth_devices); + rc = 0; +out: + return rc; +fail: + dev_put(dev); + free_netdev(ndev); + goto out; +} + +/* Free a lapb network device. + */ +static void lapbeth_free_device(struct lapbethdev *lapbeth) +{ + dev_put(lapbeth->ethdev); + list_del_rcu(&lapbeth->node); + unregister_netdevice(lapbeth->axdev); +} + +/* Handle device status changes. + * + * Called from notifier with RTNL held. + */ +static int lapbeth_device_event(struct notifier_block *this, + unsigned long event, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct lapbethdev *lapbeth; + + if (dev_net(dev) != &init_net) + return NOTIFY_DONE; + + lapbeth = lapbeth_get_x25_dev(dev); + if (!dev_is_ethdev(dev) && !lapbeth) + return NOTIFY_DONE; + + switch (event) { + case NETDEV_UP: + /* New ethernet device -> new LAPB interface */ + if (!lapbeth) + lapbeth_new_device(dev); + break; + case NETDEV_GOING_DOWN: + /* ethernet device closes -> close LAPB interface */ + if (lapbeth) + dev_close(lapbeth->axdev); + break; + case NETDEV_UNREGISTER: + /* ethernet device disappears -> remove LAPB interface */ + if (lapbeth) + lapbeth_free_device(lapbeth); + break; + case NETDEV_PRE_TYPE_CHANGE: + /* Our underlying device type must not change. */ + if (lapbeth) + return NOTIFY_BAD; + } + + return NOTIFY_DONE; +} + +/* ------------------------------------------------------------------------ */ + +static struct packet_type lapbeth_packet_type __read_mostly = { + .type = cpu_to_be16(ETH_P_DEC), + .func = lapbeth_rcv, +}; + +static struct notifier_block lapbeth_dev_notifier = { + .notifier_call = lapbeth_device_event, +}; + +static const char banner[] __initconst = + KERN_INFO "LAPB Ethernet driver version 0.02\n"; + +static int __init lapbeth_init_driver(void) +{ + int err; + + dev_add_pack(&lapbeth_packet_type); + + err = register_netdevice_notifier(&lapbeth_dev_notifier); + if (err) { + dev_remove_pack(&lapbeth_packet_type); + return err; + } + + printk(banner); + + return 0; +} +module_init(lapbeth_init_driver); + +static void __exit lapbeth_cleanup_driver(void) +{ + struct lapbethdev *lapbeth; + struct list_head *entry, *tmp; + + dev_remove_pack(&lapbeth_packet_type); + unregister_netdevice_notifier(&lapbeth_dev_notifier); + + rtnl_lock(); + list_for_each_safe(entry, tmp, &lapbeth_devices) { + lapbeth = list_entry(entry, struct lapbethdev, node); + + dev_put(lapbeth->ethdev); + unregister_netdevice(lapbeth->axdev); + } + rtnl_unlock(); +} +module_exit(lapbeth_cleanup_driver); + +MODULE_AUTHOR("Jonathan Naylor "); +MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1