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