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#endif
27#ifdef CONFIG_USER_NS
28 &userns_operations,
29#endif
30 &mntns_operations,
31#ifdef CONFIG_CGROUPS
32 &cgroupns_operations,
33#endif
34};
35
36static const char *proc_ns_get_link(struct dentry *dentry,
37 struct inode *inode,
38 struct delayed_call *done)
39{
40 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
41 struct task_struct *task;
42 struct path ns_path;
43 void *error = ERR_PTR(-EACCES);
44
45 if (!dentry)
46 return ERR_PTR(-ECHILD);
47
48 task = get_proc_task(inode);
49 if (!task)
50 return error;
51
52 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
53 error = ns_get_path(&ns_path, task, ns_ops);
54 if (!error)
55 nd_jump_link(&ns_path);
56 }
57 put_task_struct(task);
58 return error;
59}
60
61static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
62{
63 struct inode *inode = d_inode(dentry);
64 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
65 struct task_struct *task;
66 char name[50];
67 int res = -EACCES;
68
69 task = get_proc_task(inode);
70 if (!task)
71 return res;
72
73 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
74 res = ns_get_name(name, sizeof(name), task, ns_ops);
75 if (res >= 0)
76 res = readlink_copy(buffer, buflen, name);
77 }
78 put_task_struct(task);
79 return res;
80}
81
82static const struct inode_operations proc_ns_link_inode_operations = {
83 .readlink = proc_ns_readlink,
84 .get_link = proc_ns_get_link,
85 .setattr = proc_setattr,
86};
87
88static int proc_ns_instantiate(struct inode *dir,
89 struct dentry *dentry, struct task_struct *task, const void *ptr)
90{
91 const struct proc_ns_operations *ns_ops = ptr;
92 struct inode *inode;
93 struct proc_inode *ei;
94
95 inode = proc_pid_make_inode(dir->i_sb, task);
96 if (!inode)
97 goto out;
98
99 ei = PROC_I(inode);
100 inode->i_mode = S_IFLNK|S_IRWXUGO;
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 = proc_ns_dir_readdir,
143};
144
145static struct dentry *proc_ns_dir_lookup(struct inode *dir,
146 struct dentry *dentry, unsigned int flags)
147{
148 int error;
149 struct task_struct *task = get_proc_task(dir);
150 const struct proc_ns_operations **entry, **last;
151 unsigned int len = dentry->d_name.len;
152
153 error = -ENOENT;
154
155 if (!task)
156 goto out_no_task;
157
158 last = &ns_entries[ARRAY_SIZE(ns_entries)];
159 for (entry = ns_entries; entry < last; entry++) {
160 if (strlen((*entry)->name) != len)
161 continue;
162 if (!memcmp(dentry->d_name.name, (*entry)->name, len))
163 break;
164 }
165 if (entry == last)
166 goto out;
167
168 error = proc_ns_instantiate(dir, dentry, task, *entry);
169out:
170 put_task_struct(task);
171out_no_task:
172 return ERR_PTR(error);
173}
174
175const struct inode_operations proc_ns_dir_inode_operations = {
176 .lookup = proc_ns_dir_lookup,
177 .getattr = pid_getattr,
178 .setattr = proc_setattr,
179};