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 --- net/mptcp/ctrl.c | 605 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 605 insertions(+) create mode 100644 net/mptcp/ctrl.c (limited to 'net/mptcp/ctrl.c') diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c new file mode 100644 index 000000000..63c5747f0 --- /dev/null +++ b/net/mptcp/ctrl.c @@ -0,0 +1,605 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Multipath TCP + * + * Copyright (c) 2019, Tessares SA. + */ + +#ifdef CONFIG_SYSCTL +#include +#endif + +#include +#include + +#include "protocol.h" +#include "mib.h" + +#define MPTCP_SYSCTL_PATH "net/mptcp" + +static int mptcp_pernet_id; + +#ifdef CONFIG_SYSCTL +static int mptcp_pm_type_max = __MPTCP_PM_TYPE_MAX; +#endif + +struct mptcp_pernet { +#ifdef CONFIG_SYSCTL + struct ctl_table_header *ctl_table_hdr; +#endif + + unsigned int add_addr_timeout; + unsigned int blackhole_timeout; + unsigned int close_timeout; + unsigned int stale_loss_cnt; + atomic_t active_disable_times; + unsigned long active_disable_stamp; + u8 syn_retrans_before_tcp_fallback; + u8 mptcp_enabled; + u8 checksum_enabled; + u8 allow_join_initial_addr_port; + u8 pm_type; + u8 add_addr_v6_port_drop_ts; + char scheduler[MPTCP_SCHED_NAME_MAX]; + char path_manager[MPTCP_PM_NAME_MAX]; +}; + +static struct mptcp_pernet *mptcp_get_pernet(const struct net *net) +{ + return net_generic(net, mptcp_pernet_id); +} + +int mptcp_is_enabled(const struct net *net) +{ + return mptcp_get_pernet(net)->mptcp_enabled; +} + +unsigned int mptcp_get_add_addr_timeout(const struct net *net) +{ + return mptcp_get_pernet(net)->add_addr_timeout; +} + +int mptcp_is_checksum_enabled(const struct net *net) +{ + return mptcp_get_pernet(net)->checksum_enabled; +} + +int mptcp_allow_join_id0(const struct net *net) +{ + return mptcp_get_pernet(net)->allow_join_initial_addr_port; +} + +unsigned int mptcp_stale_loss_cnt(const struct net *net) +{ + return mptcp_get_pernet(net)->stale_loss_cnt; +} + +unsigned int mptcp_close_timeout(const struct sock *sk) +{ + if (sock_flag(sk, SOCK_DEAD)) + return TCP_TIMEWAIT_LEN; + return mptcp_get_pernet(sock_net(sk))->close_timeout; +} + +int mptcp_get_pm_type(const struct net *net) +{ + return mptcp_get_pernet(net)->pm_type; +} + +const char *mptcp_get_path_manager(const struct net *net) +{ + return mptcp_get_pernet(net)->path_manager; +} + +const char *mptcp_get_scheduler(const struct net *net) +{ + return mptcp_get_pernet(net)->scheduler; +} + +unsigned int mptcp_add_addr_v6_port_drop_ts(const struct net *net) +{ + return READ_ONCE(mptcp_get_pernet(net)->add_addr_v6_port_drop_ts); +} + +static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet) +{ + pernet->mptcp_enabled = 1; + pernet->add_addr_timeout = TCP_RTO_MAX; + pernet->blackhole_timeout = 3600; + pernet->syn_retrans_before_tcp_fallback = 2; + atomic_set(&pernet->active_disable_times, 0); + pernet->close_timeout = TCP_TIMEWAIT_LEN; + pernet->checksum_enabled = 0; + pernet->allow_join_initial_addr_port = 1; + pernet->stale_loss_cnt = 4; + pernet->pm_type = MPTCP_PM_TYPE_KERNEL; + strscpy(pernet->scheduler, "default", sizeof(pernet->scheduler)); + strscpy(pernet->path_manager, "kernel", sizeof(pernet->path_manager)); + pernet->add_addr_v6_port_drop_ts = 1; +} + +#ifdef CONFIG_SYSCTL +static int mptcp_set_scheduler(char *scheduler, const char *name) +{ + struct mptcp_sched_ops *sched; + int ret = 0; + + rcu_read_lock(); + sched = mptcp_sched_find(name); + if (sched) + strscpy(scheduler, name, MPTCP_SCHED_NAME_MAX); + else + ret = -ENOENT; + rcu_read_unlock(); + + return ret; +} + +static int proc_scheduler(const struct ctl_table *ctl, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + char (*scheduler)[MPTCP_SCHED_NAME_MAX] = ctl->data; + char val[MPTCP_SCHED_NAME_MAX]; + struct ctl_table tbl = { + .data = val, + .maxlen = MPTCP_SCHED_NAME_MAX, + }; + int ret; + + strscpy(val, *scheduler, MPTCP_SCHED_NAME_MAX); + + ret = proc_dostring(&tbl, write, buffer, lenp, ppos); + if (write && ret == 0) + ret = mptcp_set_scheduler(*scheduler, val); + + return ret; +} + +static int proc_available_schedulers(const struct ctl_table *ctl, + int write, void *buffer, + size_t *lenp, loff_t *ppos) +{ + struct ctl_table tbl = { .maxlen = MPTCP_SCHED_BUF_MAX, }; + int ret; + + tbl.data = kmalloc(tbl.maxlen, GFP_USER); + if (!tbl.data) + return -ENOMEM; + + mptcp_get_available_schedulers(tbl.data, MPTCP_SCHED_BUF_MAX); + ret = proc_dostring(&tbl, write, buffer, lenp, ppos); + kfree(tbl.data); + + return ret; +} + +static int proc_blackhole_detect_timeout(const struct ctl_table *table, + int write, void *buffer, size_t *lenp, + loff_t *ppos) +{ + struct mptcp_pernet *pernet = container_of(table->data, + struct mptcp_pernet, + blackhole_timeout); + int ret; + + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + if (write && ret == 0) + atomic_set(&pernet->active_disable_times, 0); + + return ret; +} + +static int mptcp_set_path_manager(char *path_manager, const char *name) +{ + struct mptcp_pm_ops *pm_ops; + int ret = 0; + + rcu_read_lock(); + pm_ops = mptcp_pm_find(name); + if (pm_ops) + strscpy(path_manager, name, MPTCP_PM_NAME_MAX); + else + ret = -ENOENT; + rcu_read_unlock(); + + return ret; +} + +static int proc_path_manager(const struct ctl_table *ctl, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct mptcp_pernet *pernet = container_of(ctl->data, + struct mptcp_pernet, + path_manager); + char (*path_manager)[MPTCP_PM_NAME_MAX] = ctl->data; + char pm_name[MPTCP_PM_NAME_MAX]; + const struct ctl_table tbl = { + .data = pm_name, + .maxlen = MPTCP_PM_NAME_MAX, + }; + int ret; + + strscpy(pm_name, *path_manager, MPTCP_PM_NAME_MAX); + + ret = proc_dostring(&tbl, write, buffer, lenp, ppos); + if (write && ret == 0) { + ret = mptcp_set_path_manager(*path_manager, pm_name); + if (ret == 0) { + u8 pm_type = __MPTCP_PM_TYPE_NR; + + if (strncmp(pm_name, "kernel", MPTCP_PM_NAME_MAX) == 0) + pm_type = MPTCP_PM_TYPE_KERNEL; + else if (strncmp(pm_name, "userspace", MPTCP_PM_NAME_MAX) == 0) + pm_type = MPTCP_PM_TYPE_USERSPACE; + pernet->pm_type = pm_type; + } + } + + return ret; +} + +static int proc_pm_type(const struct ctl_table *ctl, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct mptcp_pernet *pernet = container_of(ctl->data, + struct mptcp_pernet, + pm_type); + int ret; + + ret = proc_dou8vec_minmax(ctl, write, buffer, lenp, ppos); + if (write && ret == 0) { + u8 pm_type = READ_ONCE(*(u8 *)ctl->data); + char *pm_name = ""; + + if (pm_type == MPTCP_PM_TYPE_KERNEL) + pm_name = "kernel"; + else if (pm_type == MPTCP_PM_TYPE_USERSPACE) + pm_name = "userspace"; + mptcp_set_path_manager(pernet->path_manager, pm_name); + } + + return ret; +} + +static int proc_available_path_managers(const struct ctl_table *ctl, + int write, void *buffer, + size_t *lenp, loff_t *ppos) +{ + struct ctl_table tbl = { .maxlen = MPTCP_PM_BUF_MAX, }; + int ret; + + tbl.data = kmalloc(tbl.maxlen, GFP_USER); + if (!tbl.data) + return -ENOMEM; + + mptcp_pm_get_available(tbl.data, MPTCP_PM_BUF_MAX); + ret = proc_dostring(&tbl, write, buffer, lenp, ppos); + kfree(tbl.data); + + return ret; +} + +static struct ctl_table mptcp_sysctl_table[] = { + { + .procname = "enabled", + .maxlen = sizeof(u8), + .mode = 0644, + /* users with CAP_NET_ADMIN or root (not and) can change this + * value, same as other sysctl or the 'net' tree. + */ + .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE + }, + { + .procname = "add_addr_timeout", + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { + .procname = "checksum_enabled", + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE + }, + { + .procname = "allow_join_initial_addr_port", + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE + }, + { + .procname = "stale_loss_cnt", + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_douintvec_minmax, + }, + { + .procname = "pm_type", + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_pm_type, + .extra1 = SYSCTL_ZERO, + .extra2 = &mptcp_pm_type_max + }, + { + .procname = "scheduler", + .maxlen = MPTCP_SCHED_NAME_MAX, + .mode = 0644, + .proc_handler = proc_scheduler, + }, + { + .procname = "available_schedulers", + .maxlen = MPTCP_SCHED_BUF_MAX, + .mode = 0444, + .proc_handler = proc_available_schedulers, + }, + { + .procname = "close_timeout", + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_jiffies, + }, + { + .procname = "blackhole_timeout", + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_blackhole_detect_timeout, + .extra1 = SYSCTL_ZERO, + }, + { + .procname = "syn_retrans_before_tcp_fallback", + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_dou8vec_minmax, + }, + { + .procname = "path_manager", + .maxlen = MPTCP_PM_NAME_MAX, + .mode = 0644, + .proc_handler = proc_path_manager, + }, + { + .procname = "available_path_managers", + .maxlen = MPTCP_PM_BUF_MAX, + .mode = 0444, + .proc_handler = proc_available_path_managers, + }, + { + .procname = "add_addr_v6_port_drop_ts", + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE + }, +}; + +static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet) +{ + struct ctl_table_header *hdr; + struct ctl_table *table; + + table = mptcp_sysctl_table; + if (!net_eq(net, &init_net)) { + table = kmemdup(table, sizeof(mptcp_sysctl_table), GFP_KERNEL); + if (!table) + goto err_alloc; + } + + table[0].data = &pernet->mptcp_enabled; + table[1].data = &pernet->add_addr_timeout; + table[2].data = &pernet->checksum_enabled; + table[3].data = &pernet->allow_join_initial_addr_port; + table[4].data = &pernet->stale_loss_cnt; + table[5].data = &pernet->pm_type; + table[6].data = &pernet->scheduler; + /* table[7] is for available_schedulers which is read-only info */ + table[8].data = &pernet->close_timeout; + table[9].data = &pernet->blackhole_timeout; + table[10].data = &pernet->syn_retrans_before_tcp_fallback; + table[11].data = &pernet->path_manager; + /* table[12] is for available_path_managers which is read-only info */ + table[13].data = &pernet->add_addr_v6_port_drop_ts; + + hdr = register_net_sysctl_sz(net, MPTCP_SYSCTL_PATH, table, + ARRAY_SIZE(mptcp_sysctl_table)); + if (!hdr) + goto err_reg; + + pernet->ctl_table_hdr = hdr; + + return 0; + +err_reg: + if (!net_eq(net, &init_net)) + kfree(table); +err_alloc: + return -ENOMEM; +} + +static void mptcp_pernet_del_table(struct mptcp_pernet *pernet) +{ + const struct ctl_table *table = pernet->ctl_table_hdr->ctl_table_arg; + + unregister_net_sysctl_table(pernet->ctl_table_hdr); + + kfree(table); +} + +#else + +static int mptcp_pernet_new_table(struct net *net, struct mptcp_pernet *pernet) +{ + return 0; +} + +static void mptcp_pernet_del_table(struct mptcp_pernet *pernet) {} + +#endif /* CONFIG_SYSCTL */ + +/* The following code block is to deal with middle box issues with MPTCP, + * similar to what is done with TFO. + * The proposed solution is to disable active MPTCP globally when SYN+MPC are + * dropped, while SYN without MPC aren't. In this case, active side MPTCP is + * disabled globally for 1hr at first. Then if it happens again, it is disabled + * for 2h, then 4h, 8h, ... + * The timeout is reset back to 1hr when a successful active MPTCP connection is + * fully established. + */ + +/* Disable active MPTCP and record current jiffies and active_disable_times */ +void mptcp_active_disable(struct sock *sk) +{ + struct net *net = sock_net(sk); + struct mptcp_pernet *pernet; + + pernet = mptcp_get_pernet(net); + + if (!READ_ONCE(pernet->blackhole_timeout)) + return; + + /* Paired with READ_ONCE() in mptcp_active_should_disable() */ + WRITE_ONCE(pernet->active_disable_stamp, jiffies); + + /* Paired with smp_rmb() in mptcp_active_should_disable(). + * We want pernet->active_disable_stamp to be updated first. + */ + smp_mb__before_atomic(); + atomic_inc(&pernet->active_disable_times); + + MPTCP_INC_STATS(net, MPTCP_MIB_BLACKHOLE); +} + +/* Calculate timeout for MPTCP active disable + * Return true if we are still in the active MPTCP disable period + * Return false if timeout already expired and we should use active MPTCP + */ +bool mptcp_active_should_disable(struct sock *ssk) +{ + struct net *net = sock_net(ssk); + unsigned int blackhole_timeout; + struct mptcp_pernet *pernet; + unsigned long timeout; + int disable_times; + int multiplier; + + pernet = mptcp_get_pernet(net); + blackhole_timeout = READ_ONCE(pernet->blackhole_timeout); + + if (!blackhole_timeout) + return false; + + disable_times = atomic_read(&pernet->active_disable_times); + if (!disable_times) + return false; + + /* Paired with smp_mb__before_atomic() in mptcp_active_disable() */ + smp_rmb(); + + /* Limit timeout to max: 2^6 * initial timeout */ + multiplier = 1 << min(disable_times - 1, 6); + + /* Paired with the WRITE_ONCE() in mptcp_active_disable(). */ + timeout = READ_ONCE(pernet->active_disable_stamp) + + multiplier * blackhole_timeout * HZ; + + return time_before(jiffies, timeout); +} + +/* Enable active MPTCP and reset active_disable_times if needed */ +void mptcp_active_enable(struct sock *sk) +{ + struct mptcp_pernet *pernet = mptcp_get_pernet(sock_net(sk)); + + if (atomic_read(&pernet->active_disable_times)) { + struct net_device *dev; + struct dst_entry *dst; + + rcu_read_lock(); + dst = __sk_dst_get(sk); + dev = dst ? dst_dev_rcu(dst) : NULL; + if (!(dev && (dev->flags & IFF_LOOPBACK))) + atomic_set(&pernet->active_disable_times, 0); + rcu_read_unlock(); + } +} + +/* Check the number of retransmissions, and fallback to TCP if needed */ +void mptcp_active_detect_blackhole(struct sock *ssk, bool expired) +{ + struct mptcp_subflow_context *subflow; + u8 timeouts, to_max; + struct net *net; + + /* Only check MPTCP SYN ... */ + if (likely(!sk_is_mptcp(ssk) || ssk->sk_state != TCP_SYN_SENT)) + return; + + subflow = mptcp_subflow_ctx(ssk); + + /* ... + MP_CAPABLE */ + if (!subflow->request_mptcp) { + /* Mark as blackhole iif the 1st non-MPTCP SYN is accepted */ + subflow->mpc_drop = 0; + return; + } + + net = sock_net(ssk); + timeouts = inet_csk(ssk)->icsk_retransmits; + to_max = mptcp_get_pernet(net)->syn_retrans_before_tcp_fallback; + + if (timeouts == to_max || (timeouts < to_max && expired)) { + subflow->mpc_drop = 1; + mptcp_early_fallback(mptcp_sk(subflow->conn), subflow, + MPTCP_MIB_MPCAPABLEACTIVEDROP); + } +} + +static int __net_init mptcp_net_init(struct net *net) +{ + struct mptcp_pernet *pernet = mptcp_get_pernet(net); + + mptcp_pernet_set_defaults(pernet); + + return mptcp_pernet_new_table(net, pernet); +} + +/* Note: the callback will only be called per extra netns */ +static void __net_exit mptcp_net_exit(struct net *net) +{ + struct mptcp_pernet *pernet = mptcp_get_pernet(net); + + mptcp_pernet_del_table(pernet); +} + +static struct pernet_operations mptcp_pernet_ops = { + .init = mptcp_net_init, + .exit = mptcp_net_exit, + .id = &mptcp_pernet_id, + .size = sizeof(struct mptcp_pernet), +}; + +void __init mptcp_init(void) +{ + mptcp_join_cookie_init(); + mptcp_proto_init(); + + if (register_pernet_subsys(&mptcp_pernet_ops) < 0) + panic("Failed to register MPTCP pernet subsystem.\n"); +} + +#if IS_ENABLED(CONFIG_MPTCP_IPV6) +int __init mptcpv6_init(void) +{ + int err; + + err = mptcp_proto_v6_init(); + + return err; +} +#endif -- cgit v1.3.1