From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- fs/proc/proc_net.c | 426 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 426 insertions(+) create mode 100644 fs/proc/proc_net.c (limited to 'fs/proc/proc_net.c') diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c new file mode 100644 index 000000000..00cc385bc --- /dev/null +++ b/fs/proc/proc_net.c @@ -0,0 +1,426 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/fs/proc/net.c + * + * Copyright (C) 2007 + * + * Author: Eric Biederman + * + * proc net directory handling functions + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "internal.h" + +static inline struct net *PDE_NET(struct proc_dir_entry *pde) +{ + return pde->parent->data; +} + +static struct net *get_proc_net(const struct inode *inode) +{ + return maybe_get_net(PDE_NET(PDE(inode))); +} + +static int seq_open_net(struct inode *inode, struct file *file) +{ + unsigned int state_size = PDE(inode)->state_size; + struct seq_net_private *p; + struct net *net; + + WARN_ON_ONCE(state_size < sizeof(*p)); + + if (file->f_mode & FMODE_WRITE && !PDE(inode)->write) + return -EACCES; + + net = get_proc_net(inode); + if (!net) + return -ENXIO; + + p = __seq_open_private(file, PDE(inode)->seq_ops, state_size); + if (!p) { + put_net(net); + return -ENOMEM; + } +#ifdef CONFIG_NET_NS + p->net = net; + netns_tracker_alloc(net, &p->ns_tracker, GFP_KERNEL); +#endif + return 0; +} + +static void seq_file_net_put_net(struct seq_file *seq) +{ +#ifdef CONFIG_NET_NS + struct seq_net_private *priv = seq->private; + + put_net_track(priv->net, &priv->ns_tracker); +#else + put_net(&init_net); +#endif +} + +static int seq_release_net(struct inode *ino, struct file *f) +{ + struct seq_file *seq = f->private_data; + + seq_file_net_put_net(seq); + seq_release_private(ino, f); + return 0; +} + +static const struct proc_ops proc_net_seq_ops = { + .proc_open = seq_open_net, + .proc_read = seq_read, + .proc_write = proc_simple_write, + .proc_lseek = seq_lseek, + .proc_release = seq_release_net, +}; + +int bpf_iter_init_seq_net(void *priv_data, struct bpf_iter_aux_info *aux) +{ +#ifdef CONFIG_NET_NS + struct seq_net_private *p = priv_data; + + p->net = get_net_track(current->nsproxy->net_ns, &p->ns_tracker, + GFP_KERNEL); +#endif + return 0; +} + +void bpf_iter_fini_seq_net(void *priv_data) +{ +#ifdef CONFIG_NET_NS + struct seq_net_private *p = priv_data; + + put_net_track(p->net, &p->ns_tracker); +#endif +} + +struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode, + struct proc_dir_entry *parent, const struct seq_operations *ops, + unsigned int state_size, void *data) +{ + struct proc_dir_entry *p; + + p = proc_create_reg(name, mode, &parent, data); + if (!p) + return NULL; + pde_force_lookup(p); + p->proc_ops = &proc_net_seq_ops; + p->seq_ops = ops; + p->state_size = state_size; + return proc_register(parent, p); +} +EXPORT_SYMBOL_GPL(proc_create_net_data); + +/** + * proc_create_net_data_write - Create a writable net_ns-specific proc file + * @name: The name of the file. + * @mode: The file's access mode. + * @parent: The parent directory in which to create. + * @ops: The seq_file ops with which to read the file. + * @write: The write method with which to 'modify' the file. + * @state_size: The size of the per-file private state to allocate. + * @data: Data for retrieval by pde_data(). + * + * Create a network namespaced proc file in the @parent directory with the + * specified @name and @mode that allows reading of a file that displays a + * series of elements and also provides for the file accepting writes that have + * some arbitrary effect. + * + * The functions in the @ops table are used to iterate over items to be + * presented and extract the readable content using the seq_file interface. + * + * The @write function is called with the data copied into a kernel space + * scratch buffer and has a NUL appended for convenience. The buffer may be + * modified by the @write function. @write should return 0 on success. + * + * The @data value is accessible from the @show and @write functions by calling + * pde_data() on the file inode. The network namespace must be accessed by + * calling seq_file_net() on the seq_file struct. + */ +struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode, + struct proc_dir_entry *parent, + const struct seq_operations *ops, + proc_write_t write, + unsigned int state_size, void *data) +{ + struct proc_dir_entry *p; + + p = proc_create_reg(name, mode, &parent, data); + if (!p) + return NULL; + pde_force_lookup(p); + p->proc_ops = &proc_net_seq_ops; + p->seq_ops = ops; + p->state_size = state_size; + p->write = write; + return proc_register(parent, p); +} +EXPORT_SYMBOL_GPL(proc_create_net_data_write); + +static int single_open_net(struct inode *inode, struct file *file) +{ + struct proc_dir_entry *de = PDE(inode); + struct net *net; + int err; + + net = get_proc_net(inode); + if (!net) + return -ENXIO; + + err = single_open(file, de->single_show, net); + if (err) + put_net(net); + return err; +} + +static int single_release_net(struct inode *ino, struct file *f) +{ + struct seq_file *seq = f->private_data; + put_net(seq->private); + return single_release(ino, f); +} + +static const struct proc_ops proc_net_single_ops = { + .proc_open = single_open_net, + .proc_read = seq_read, + .proc_write = proc_simple_write, + .proc_lseek = seq_lseek, + .proc_release = single_release_net, +}; + +struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode, + struct proc_dir_entry *parent, + int (*show)(struct seq_file *, void *), void *data) +{ + struct proc_dir_entry *p; + + p = proc_create_reg(name, mode, &parent, data); + if (!p) + return NULL; + pde_force_lookup(p); + p->proc_ops = &proc_net_single_ops; + p->single_show = show; + return proc_register(parent, p); +} +EXPORT_SYMBOL_GPL(proc_create_net_single); + +/** + * proc_create_net_single_write - Create a writable net_ns-specific proc file + * @name: The name of the file. + * @mode: The file's access mode. + * @parent: The parent directory in which to create. + * @show: The seqfile show method with which to read the file. + * @write: The write method with which to 'modify' the file. + * @data: Data for retrieval by pde_data(). + * + * Create a network-namespaced proc file in the @parent directory with the + * specified @name and @mode that allows reading of a file that displays a + * single element rather than a series and also provides for the file accepting + * writes that have some arbitrary effect. + * + * The @show function is called to extract the readable content via the + * seq_file interface. + * + * The @write function is called with the data copied into a kernel space + * scratch buffer and has a NUL appended for convenience. The buffer may be + * modified by the @write function. @write should return 0 on success. + * + * The @data value is accessible from the @show and @write functions by calling + * pde_data() on the file inode. The network namespace must be accessed by + * calling seq_file_single_net() on the seq_file struct. + */ +struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode, + struct proc_dir_entry *parent, + int (*show)(struct seq_file *, void *), + proc_write_t write, + void *data) +{ + struct proc_dir_entry *p; + + p = proc_create_reg(name, mode, &parent, data); + if (!p) + return NULL; + pde_force_lookup(p); + p->proc_ops = &proc_net_single_ops; + p->single_show = show; + p->write = write; + return proc_register(parent, p); +} +EXPORT_SYMBOL_GPL(proc_create_net_single_write); + +static struct net *get_proc_task_net(struct inode *dir) +{ + struct task_struct *task; + struct nsproxy *ns; + struct net *net = NULL; + struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb); + + rcu_read_lock(); + task = pid_task(proc_pid(dir), PIDTYPE_PID); + if (task != NULL) { + task_lock(task); + ns = task->nsproxy; + if (ns != NULL) + net = get_net(ns->net_ns); + task_unlock(task); + } + rcu_read_unlock(); + + if (net && (fs_info->pidonly == PROC_PIDONLY_ON) && + security_capable(fs_info->mounter_cred, net->user_ns, CAP_NET_ADMIN, CAP_OPT_NONE) < 0) { + put_net(net); + net = NULL; + } + + return net; +} + +static struct dentry *proc_tgid_net_lookup(struct inode *dir, + struct dentry *dentry, unsigned int flags) +{ + struct dentry *de; + struct net *net; + + de = ERR_PTR(-ENOENT); + net = get_proc_task_net(dir); + if (net != NULL) { + de = proc_lookup_de(dir, dentry, net->proc_net); + put_net(net); + } + return de; +} + +static int proc_tgid_net_getattr(struct mnt_idmap *idmap, + const struct path *path, struct kstat *stat, + u32 request_mask, unsigned int query_flags) +{ + struct inode *inode = d_inode(path->dentry); + struct net *net; + + net = get_proc_task_net(inode); + + generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); + + if (net != NULL) { + stat->nlink = net->proc_net->nlink; + put_net(net); + } + + return 0; +} + +const struct inode_operations proc_net_inode_operations = { + .lookup = proc_tgid_net_lookup, + .getattr = proc_tgid_net_getattr, + .setattr = proc_nochmod_setattr, +}; + +static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx) +{ + int ret; + struct net *net; + + ret = -EINVAL; + net = get_proc_task_net(file_inode(file)); + if (net != NULL) { + ret = proc_readdir_de(file, ctx, net->proc_net); + put_net(net); + } + return ret; +} + +const struct file_operations proc_net_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate_shared = proc_tgid_net_readdir, +}; + +static __net_init int proc_net_ns_init(struct net *net) +{ + struct proc_dir_entry *netd, *net_statd; + kuid_t uid; + kgid_t gid; + int err; + + /* + * This PDE acts only as an anchor for /proc/${pid}/net hierarchy. + * Corresponding inode (PDE(inode) == net->proc_net) is never + * instantiated therefore blanket zeroing is fine. + * net->proc_net_stat inode is instantiated normally. + */ + err = -ENOMEM; + netd = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL); + if (!netd) + goto out; + + netd->subdir = RB_ROOT; + netd->data = net; + netd->nlink = 2; + netd->namelen = 3; + netd->parent = &proc_root; + netd->name = netd->inline_name; + memcpy(netd->name, "net", 4); + + uid = make_kuid(net->user_ns, 0); + if (!uid_valid(uid)) + uid = netd->uid; + + gid = make_kgid(net->user_ns, 0); + if (!gid_valid(gid)) + gid = netd->gid; + + proc_set_user(netd, uid, gid); + + /* Seed dentry revalidation for /proc/${pid}/net */ + pde_force_lookup(netd); + + err = -EEXIST; + net_statd = proc_net_mkdir(net, "stat", netd); + if (!net_statd) + goto free_net; + + net->proc_net = netd; + net->proc_net_stat = net_statd; + return 0; + +free_net: + pde_free(netd); +out: + return err; +} + +static __net_exit void proc_net_ns_exit(struct net *net) +{ + remove_proc_entry("stat", net->proc_net); + pde_free(net->proc_net); +} + +static struct pernet_operations __net_initdata proc_net_ns_ops = { + .init = proc_net_ns_init, + .exit = proc_net_ns_exit, +}; + +int __init proc_net_init(void) +{ + proc_symlink("net", NULL, "self/net"); + + return register_pernet_subsys(&proc_net_ns_ops); +} -- cgit v1.3.1