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};
32
33static const char *proc_ns_get_link(struct dentry *dentry,
34 struct inode *inode,
35 struct delayed_call *done)
36{
37 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
38 struct task_struct *task;
39 struct path ns_path;
40 void *error = ERR_PTR(-EACCES);
41
42 if (!dentry)
43 return ERR_PTR(-ECHILD);
44
45 task = get_proc_task(inode);
46 if (!task)
47 return error;
48
49 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
50 error = ns_get_path(&ns_path, task, ns_ops);
51 if (!error)
52 nd_jump_link(&ns_path);
53 }
54 put_task_struct(task);
55 return error;
56}
57
58static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
59{
60 struct inode *inode = d_inode(dentry);
61 const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
62 struct task_struct *task;
63 char name[50];
64 int res = -EACCES;
65
66 task = get_proc_task(inode);
67 if (!task)
68 return res;
69
70 if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
71 res = ns_get_name(name, sizeof(name), task, ns_ops);
72 if (res >= 0)
73 res = readlink_copy(buffer, buflen, name);
74 }
75 put_task_struct(task);
76 return res;
77}
78
79static const struct inode_operations proc_ns_link_inode_operations = {
80 .readlink = proc_ns_readlink,
81 .get_link = proc_ns_get_link,
82 .setattr = proc_setattr,
83};
84
85static int proc_ns_instantiate(struct inode *dir,
86 struct dentry *dentry, struct task_struct *task, const void *ptr)
87{
88 const struct proc_ns_operations *ns_ops = ptr;
89 struct inode *inode;
90 struct proc_inode *ei;
91
92 inode = proc_pid_make_inode(dir->i_sb, task);
93 if (!inode)
94 goto out;
95
96 ei = PROC_I(inode);
97 inode->i_mode = S_IFLNK|S_IRWXUGO;
98 inode->i_op = &proc_ns_link_inode_operations;
99 ei->ns_ops = ns_ops;
100
101 d_set_d_op(dentry, &pid_dentry_operations);
102 d_add(dentry, inode);
103 /* Close the race of the process dying before we return the dentry */
104 if (pid_revalidate(dentry, 0))
105 return 0;
106out:
107 return -ENOENT;
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 = proc_ns_dir_readdir,
140};
141
142static struct dentry *proc_ns_dir_lookup(struct inode *dir,
143 struct dentry *dentry, unsigned int flags)
144{
145 int error;
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
150 error = -ENOENT;
151
152 if (!task)
153 goto out_no_task;
154
155 last = &ns_entries[ARRAY_SIZE(ns_entries)];
156 for (entry = ns_entries; entry < last; entry++) {
157 if (strlen((*entry)->name) != len)
158 continue;
159 if (!memcmp(dentry->d_name.name, (*entry)->name, len))
160 break;
161 }
162 if (entry == last)
163 goto out;
164
165 error = proc_ns_instantiate(dir, dentry, task, *entry);
166out:
167 put_task_struct(task);
168out_no_task:
169 return ERR_PTR(error);
170}
171
172const struct inode_operations proc_ns_dir_inode_operations = {
173 .lookup = proc_ns_dir_lookup,
174 .getattr = pid_getattr,
175 .setattr = proc_setattr,
176};