Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#include <linux/proc_fs.h>
2#include <linux/nsproxy.h>
3#include <linux/ptrace.h>
4#include <linux/namei.h>
5#include <linux/file.h>
6#include <linux/utsname.h>
7#include <net/net_namespace.h>
8#include <linux/ipc_namespace.h>
9#include <linux/pid_namespace.h>
10#include <linux/user_namespace.h>
11#include "internal.h"
12
13
14static const struct proc_ns_operations *ns_entries[] = {
15#ifdef CONFIG_NET_NS
16 &netns_operations,
17#endif
18#ifdef CONFIG_UTS_NS
19 &utsns_operations,
20#endif
21#ifdef CONFIG_IPC_NS
22 &ipcns_operations,
23#endif
24#ifdef CONFIG_PID_NS
25 &pidns_operations,
26 &pidns_for_children_operations,
27#endif
28#ifdef CONFIG_USER_NS
29 &userns_operations,
30#endif
31 &mntns_operations,
32#ifdef CONFIG_CGROUPS
33 &cgroupns_operations,
34#endif
35};
36
37static const char *proc_ns_get_link(struct dentry *dentry,
38 struct inode *inode,
39 struct delayed_call *done)
40{
41 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
42 struct task_struct *task;
43 struct path ns_path;
44 void *error = ERR_PTR(-EACCES);
45
46 if (!dentry)
47 return ERR_PTR(-ECHILD);
48
49 task = get_proc_task(inode);
50 if (!task)
51 return error;
52
53 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
54 error = ns_get_path(&ns_path, task, ns_ops);
55 if (!error)
56 nd_jump_link(&ns_path);
57 }
58 put_task_struct(task);
59 return error;
60}
61
62static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
63{
64 struct inode *inode = d_inode(dentry);
65 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
66 struct task_struct *task;
67 char name[50];
68 int res = -EACCES;
69
70 task = get_proc_task(inode);
71 if (!task)
72 return res;
73
74 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
75 res = ns_get_name(name, sizeof(name), task, ns_ops);
76 if (res >= 0)
77 res = readlink_copy(buffer, buflen, name);
78 }
79 put_task_struct(task);
80 return res;
81}
82
83static const struct inode_operations proc_ns_link_inode_operations = {
84 .readlink = proc_ns_readlink,
85 .get_link = proc_ns_get_link,
86 .setattr = proc_setattr,
87};
88
89static int proc_ns_instantiate(struct inode *dir,
90 struct dentry *dentry, struct task_struct *task, const void *ptr)
91{
92 const struct proc_ns_operations *ns_ops = ptr;
93 struct inode *inode;
94 struct proc_inode *ei;
95
96 inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO);
97 if (!inode)
98 goto out;
99
100 ei = PROC_I(inode);
101 inode->i_op = &proc_ns_link_inode_operations;
102 ei->ns_ops = ns_ops;
103
104 d_set_d_op(dentry, &pid_dentry_operations);
105 d_add(dentry, inode);
106 /* Close the race of the process dying before we return the dentry */
107 if (pid_revalidate(dentry, 0))
108 return 0;
109out:
110 return -ENOENT;
111}
112
113static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
114{
115 struct task_struct *task = get_proc_task(file_inode(file));
116 const struct proc_ns_operations **entry, **last;
117
118 if (!task)
119 return -ENOENT;
120
121 if (!dir_emit_dots(file, ctx))
122 goto out;
123 if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
124 goto out;
125 entry = ns_entries + (ctx->pos - 2);
126 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
127 while (entry <= last) {
128 const struct proc_ns_operations *ops = *entry;
129 if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
130 proc_ns_instantiate, task, ops))
131 break;
132 ctx->pos++;
133 entry++;
134 }
135out:
136 put_task_struct(task);
137 return 0;
138}
139
140const struct file_operations proc_ns_dir_operations = {
141 .read = generic_read_dir,
142 .iterate_shared = proc_ns_dir_readdir,
143 .llseek = generic_file_llseek,
144};
145
146static struct dentry *proc_ns_dir_lookup(struct inode *dir,
147 struct dentry *dentry, unsigned int flags)
148{
149 int error;
150 struct task_struct *task = get_proc_task(dir);
151 const struct proc_ns_operations **entry, **last;
152 unsigned int len = dentry->d_name.len;
153
154 error = -ENOENT;
155
156 if (!task)
157 goto out_no_task;
158
159 last = &ns_entries[ARRAY_SIZE(ns_entries)];
160 for (entry = ns_entries; entry < last; entry++) {
161 if (strlen((*entry)->name) != len)
162 continue;
163 if (!memcmp(dentry->d_name.name, (*entry)->name, len))
164 break;
165 }
166 if (entry == last)
167 goto out;
168
169 error = proc_ns_instantiate(dir, dentry, task, *entry);
170out:
171 put_task_struct(task);
172out_no_task:
173 return ERR_PTR(error);
174}
175
176const struct inode_operations proc_ns_dir_inode_operations = {
177 .lookup = proc_ns_dir_lookup,
178 .getattr = pid_getattr,
179 .setattr = proc_setattr,
180};