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6b4e306a EB |
1 | #include <linux/proc_fs.h> |
2 | #include <linux/nsproxy.h> | |
3 | #include <linux/sched.h> | |
4 | #include <linux/ptrace.h> | |
5 | #include <linux/fs_struct.h> | |
6 | #include <linux/mount.h> | |
7 | #include <linux/path.h> | |
8 | #include <linux/namei.h> | |
9 | #include <linux/file.h> | |
10 | #include <linux/utsname.h> | |
11 | #include <net/net_namespace.h> | |
12 | #include <linux/mnt_namespace.h> | |
13 | #include <linux/ipc_namespace.h> | |
14 | #include <linux/pid_namespace.h> | |
15 | #include "internal.h" | |
16 | ||
17 | ||
18 | static const struct proc_ns_operations *ns_entries[] = { | |
13b6f576 EB |
19 | #ifdef CONFIG_NET_NS |
20 | &netns_operations, | |
21 | #endif | |
6b4e306a EB |
22 | }; |
23 | ||
24 | static const struct file_operations ns_file_operations = { | |
25 | .llseek = no_llseek, | |
26 | }; | |
27 | ||
28 | static struct dentry *proc_ns_instantiate(struct inode *dir, | |
29 | struct dentry *dentry, struct task_struct *task, const void *ptr) | |
30 | { | |
31 | const struct proc_ns_operations *ns_ops = ptr; | |
32 | struct inode *inode; | |
33 | struct proc_inode *ei; | |
34 | struct dentry *error = ERR_PTR(-ENOENT); | |
35 | ||
36 | inode = proc_pid_make_inode(dir->i_sb, task); | |
37 | if (!inode) | |
38 | goto out; | |
39 | ||
40 | ei = PROC_I(inode); | |
41 | inode->i_mode = S_IFREG|S_IRUSR; | |
42 | inode->i_fop = &ns_file_operations; | |
43 | ei->ns_ops = ns_ops; | |
44 | ei->ns = ns_ops->get(task); | |
45 | if (!ei->ns) | |
46 | goto out_iput; | |
47 | ||
48 | dentry->d_op = &pid_dentry_operations; | |
49 | d_add(dentry, inode); | |
50 | /* Close the race of the process dying before we return the dentry */ | |
51 | if (pid_revalidate(dentry, NULL)) | |
52 | error = NULL; | |
53 | out: | |
54 | return error; | |
55 | out_iput: | |
56 | iput(inode); | |
57 | goto out; | |
58 | } | |
59 | ||
60 | static int proc_ns_fill_cache(struct file *filp, void *dirent, | |
61 | filldir_t filldir, struct task_struct *task, | |
62 | const struct proc_ns_operations *ops) | |
63 | { | |
64 | return proc_fill_cache(filp, dirent, filldir, | |
65 | ops->name, strlen(ops->name), | |
66 | proc_ns_instantiate, task, ops); | |
67 | } | |
68 | ||
69 | static int proc_ns_dir_readdir(struct file *filp, void *dirent, | |
70 | filldir_t filldir) | |
71 | { | |
72 | int i; | |
73 | struct dentry *dentry = filp->f_path.dentry; | |
74 | struct inode *inode = dentry->d_inode; | |
75 | struct task_struct *task = get_proc_task(inode); | |
76 | const struct proc_ns_operations **entry, **last; | |
77 | ino_t ino; | |
78 | int ret; | |
79 | ||
80 | ret = -ENOENT; | |
81 | if (!task) | |
82 | goto out_no_task; | |
83 | ||
84 | ret = -EPERM; | |
85 | if (!ptrace_may_access(task, PTRACE_MODE_READ)) | |
86 | goto out; | |
87 | ||
88 | ret = 0; | |
89 | i = filp->f_pos; | |
90 | switch (i) { | |
91 | case 0: | |
92 | ino = inode->i_ino; | |
93 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
94 | goto out; | |
95 | i++; | |
96 | filp->f_pos++; | |
97 | /* fall through */ | |
98 | case 1: | |
99 | ino = parent_ino(dentry); | |
100 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
101 | goto out; | |
102 | i++; | |
103 | filp->f_pos++; | |
104 | /* fall through */ | |
105 | default: | |
106 | i -= 2; | |
107 | if (i >= ARRAY_SIZE(ns_entries)) { | |
108 | ret = 1; | |
109 | goto out; | |
110 | } | |
111 | entry = ns_entries + i; | |
112 | last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; | |
113 | while (entry <= last) { | |
114 | if (proc_ns_fill_cache(filp, dirent, filldir, | |
115 | task, *entry) < 0) | |
116 | goto out; | |
117 | filp->f_pos++; | |
118 | entry++; | |
119 | } | |
120 | } | |
121 | ||
122 | ret = 1; | |
123 | out: | |
124 | put_task_struct(task); | |
125 | out_no_task: | |
126 | return ret; | |
127 | } | |
128 | ||
129 | const struct file_operations proc_ns_dir_operations = { | |
130 | .read = generic_read_dir, | |
131 | .readdir = proc_ns_dir_readdir, | |
132 | }; | |
133 | ||
134 | static struct dentry *proc_ns_dir_lookup(struct inode *dir, | |
135 | struct dentry *dentry, struct nameidata *nd) | |
136 | { | |
137 | struct dentry *error; | |
138 | struct task_struct *task = get_proc_task(dir); | |
139 | const struct proc_ns_operations **entry, **last; | |
140 | unsigned int len = dentry->d_name.len; | |
141 | ||
142 | error = ERR_PTR(-ENOENT); | |
143 | ||
144 | if (!task) | |
145 | goto out_no_task; | |
146 | ||
147 | error = ERR_PTR(-EPERM); | |
148 | if (!ptrace_may_access(task, PTRACE_MODE_READ)) | |
149 | goto out; | |
150 | ||
151 | last = &ns_entries[ARRAY_SIZE(ns_entries) - 1]; | |
152 | for (entry = ns_entries; entry <= last; entry++) { | |
153 | if (strlen((*entry)->name) != len) | |
154 | continue; | |
155 | if (!memcmp(dentry->d_name.name, (*entry)->name, len)) | |
156 | break; | |
157 | } | |
158 | if (entry > last) | |
159 | goto out; | |
160 | ||
161 | error = proc_ns_instantiate(dir, dentry, task, *entry); | |
162 | out: | |
163 | put_task_struct(task); | |
164 | out_no_task: | |
165 | return error; | |
166 | } | |
167 | ||
168 | const struct inode_operations proc_ns_dir_inode_operations = { | |
169 | .lookup = proc_ns_dir_lookup, | |
170 | .getattr = pid_getattr, | |
171 | .setattr = proc_setattr, | |
172 | }; | |
173 | ||
174 | struct file *proc_ns_fget(int fd) | |
175 | { | |
176 | struct file *file; | |
177 | ||
178 | file = fget(fd); | |
179 | if (!file) | |
180 | return ERR_PTR(-EBADF); | |
181 | ||
182 | if (file->f_op != &ns_file_operations) | |
183 | goto out_invalid; | |
184 | ||
185 | return file; | |
186 | ||
187 | out_invalid: | |
188 | fput(file); | |
189 | return ERR_PTR(-EINVAL); | |
190 | } | |
191 |