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10#include <linux/uaccess.h>
11
12#include <linux/errno.h>
13#include <linux/time.h>
14#include <linux/proc_fs.h>
15#include <linux/stat.h>
16#include <linux/init.h>
17#include <linux/sched.h>
18#include <linux/sched/stat.h>
19#include <linux/module.h>
20#include <linux/bitops.h>
21#include <linux/user_namespace.h>
22#include <linux/fs_context.h>
23#include <linux/mount.h>
24#include <linux/pid_namespace.h>
25#include <linux/fs_parser.h>
26#include <linux/cred.h>
27#include <linux/magic.h>
28#include <linux/slab.h>
29
30#include "internal.h"
31
32struct proc_fs_context {
33 struct pid_namespace *pid_ns;
34 unsigned int mask;
35 int hidepid;
36 int gid;
37};
38
39enum proc_param {
40 Opt_gid,
41 Opt_hidepid,
42};
43
44static const struct fs_parameter_spec proc_param_specs[] = {
45 fsparam_u32("gid", Opt_gid),
46 fsparam_u32("hidepid", Opt_hidepid),
47 {}
48};
49
50static const struct fs_parameter_description proc_fs_parameters = {
51 .name = "proc",
52 .specs = proc_param_specs,
53};
54
55static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
56{
57 struct proc_fs_context *ctx = fc->fs_private;
58 struct fs_parse_result result;
59 int opt;
60
61 opt = fs_parse(fc, &proc_fs_parameters, param, &result);
62 if (opt < 0)
63 return opt;
64
65 switch (opt) {
66 case Opt_gid:
67 ctx->gid = result.uint_32;
68 break;
69
70 case Opt_hidepid:
71 ctx->hidepid = result.uint_32;
72 if (ctx->hidepid < HIDEPID_OFF ||
73 ctx->hidepid > HIDEPID_INVISIBLE)
74 return invalf(fc, "proc: hidepid value must be between 0 and 2.\n");
75 break;
76
77 default:
78 return -EINVAL;
79 }
80
81 ctx->mask |= 1 << opt;
82 return 0;
83}
84
85static void proc_apply_options(struct super_block *s,
86 struct fs_context *fc,
87 struct pid_namespace *pid_ns,
88 struct user_namespace *user_ns)
89{
90 struct proc_fs_context *ctx = fc->fs_private;
91
92 if (ctx->mask & (1 << Opt_gid))
93 pid_ns->pid_gid = make_kgid(user_ns, ctx->gid);
94 if (ctx->mask & (1 << Opt_hidepid))
95 pid_ns->hide_pid = ctx->hidepid;
96}
97
98static int proc_fill_super(struct super_block *s, struct fs_context *fc)
99{
100 struct pid_namespace *pid_ns = get_pid_ns(s->s_fs_info);
101 struct inode *root_inode;
102 int ret;
103
104 proc_apply_options(s, fc, pid_ns, current_user_ns());
105
106
107 s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
108 s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
109 s->s_blocksize = 1024;
110 s->s_blocksize_bits = 10;
111 s->s_magic = PROC_SUPER_MAGIC;
112 s->s_op = &proc_sops;
113 s->s_time_gran = 1;
114
115
116
117
118
119
120 s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
121
122
123 s->s_shrink.seeks = 0;
124
125 pde_get(&proc_root);
126 root_inode = proc_get_inode(s, &proc_root);
127 if (!root_inode) {
128 pr_err("proc_fill_super: get root inode failed\n");
129 return -ENOMEM;
130 }
131
132 s->s_root = d_make_root(root_inode);
133 if (!s->s_root) {
134 pr_err("proc_fill_super: allocate dentry failed\n");
135 return -ENOMEM;
136 }
137
138 ret = proc_setup_self(s);
139 if (ret) {
140 return ret;
141 }
142 return proc_setup_thread_self(s);
143}
144
145static int proc_reconfigure(struct fs_context *fc)
146{
147 struct super_block *sb = fc->root->d_sb;
148 struct pid_namespace *pid = sb->s_fs_info;
149
150 sync_filesystem(sb);
151
152 proc_apply_options(sb, fc, pid, current_user_ns());
153 return 0;
154}
155
156static int proc_get_tree(struct fs_context *fc)
157{
158 struct proc_fs_context *ctx = fc->fs_private;
159
160 fc->s_fs_info = ctx->pid_ns;
161 return vfs_get_super(fc, vfs_get_keyed_super, proc_fill_super);
162}
163
164static void proc_fs_context_free(struct fs_context *fc)
165{
166 struct proc_fs_context *ctx = fc->fs_private;
167
168 put_pid_ns(ctx->pid_ns);
169 kfree(ctx);
170}
171
172static const struct fs_context_operations proc_fs_context_ops = {
173 .free = proc_fs_context_free,
174 .parse_param = proc_parse_param,
175 .get_tree = proc_get_tree,
176 .reconfigure = proc_reconfigure,
177};
178
179static int proc_init_fs_context(struct fs_context *fc)
180{
181 struct proc_fs_context *ctx;
182
183 ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL);
184 if (!ctx)
185 return -ENOMEM;
186
187 ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
188 put_user_ns(fc->user_ns);
189 fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
190 fc->fs_private = ctx;
191 fc->ops = &proc_fs_context_ops;
192 return 0;
193}
194
195static void proc_kill_sb(struct super_block *sb)
196{
197 struct pid_namespace *ns;
198
199 ns = (struct pid_namespace *)sb->s_fs_info;
200 if (ns->proc_self)
201 dput(ns->proc_self);
202 if (ns->proc_thread_self)
203 dput(ns->proc_thread_self);
204 kill_anon_super(sb);
205 put_pid_ns(ns);
206}
207
208static struct file_system_type proc_fs_type = {
209 .name = "proc",
210 .init_fs_context = proc_init_fs_context,
211 .parameters = &proc_fs_parameters,
212 .kill_sb = proc_kill_sb,
213 .fs_flags = FS_USERNS_MOUNT | FS_DISALLOW_NOTIFY_PERM,
214};
215
216void __init proc_root_init(void)
217{
218 proc_init_kmemcache();
219 set_proc_pid_nlink();
220 proc_self_init();
221 proc_thread_self_init();
222 proc_symlink("mounts", NULL, "self/mounts");
223
224 proc_net_init();
225 proc_mkdir("fs", NULL);
226 proc_mkdir("driver", NULL);
227 proc_create_mount_point("fs/nfsd");
228#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
229
230 proc_create_mount_point("openprom");
231#endif
232 proc_tty_init();
233 proc_mkdir("bus", NULL);
234 proc_sys_init();
235
236 register_filesystem(&proc_fs_type);
237}
238
239static int proc_root_getattr(const struct path *path, struct kstat *stat,
240 u32 request_mask, unsigned int query_flags)
241{
242 generic_fillattr(d_inode(path->dentry), stat);
243 stat->nlink = proc_root.nlink + nr_processes();
244 return 0;
245}
246
247static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
248{
249 if (!proc_pid_lookup(dentry, flags))
250 return NULL;
251
252 return proc_lookup(dir, dentry, flags);
253}
254
255static int proc_root_readdir(struct file *file, struct dir_context *ctx)
256{
257 if (ctx->pos < FIRST_PROCESS_ENTRY) {
258 int error = proc_readdir(file, ctx);
259 if (unlikely(error <= 0))
260 return error;
261 ctx->pos = FIRST_PROCESS_ENTRY;
262 }
263
264 return proc_pid_readdir(file, ctx);
265}
266
267
268
269
270
271
272static const struct file_operations proc_root_operations = {
273 .read = generic_read_dir,
274 .iterate_shared = proc_root_readdir,
275 .llseek = generic_file_llseek,
276};
277
278
279
280
281static const struct inode_operations proc_root_inode_operations = {
282 .lookup = proc_root_lookup,
283 .getattr = proc_root_getattr,
284};
285
286
287
288
289struct proc_dir_entry proc_root = {
290 .low_ino = PROC_ROOT_INO,
291 .namelen = 5,
292 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
293 .nlink = 2,
294 .refcnt = REFCOUNT_INIT(1),
295 .proc_iops = &proc_root_inode_operations,
296 .proc_fops = &proc_root_operations,
297 .parent = &proc_root,
298 .subdir = RB_ROOT,
299 .name = "/proc",
300};
301
302int pid_ns_prepare_proc(struct pid_namespace *ns)
303{
304 struct proc_fs_context *ctx;
305 struct fs_context *fc;
306 struct vfsmount *mnt;
307
308 fc = fs_context_for_mount(&proc_fs_type, SB_KERNMOUNT);
309 if (IS_ERR(fc))
310 return PTR_ERR(fc);
311
312 if (fc->user_ns != ns->user_ns) {
313 put_user_ns(fc->user_ns);
314 fc->user_ns = get_user_ns(ns->user_ns);
315 }
316
317 ctx = fc->fs_private;
318 if (ctx->pid_ns != ns) {
319 put_pid_ns(ctx->pid_ns);
320 get_pid_ns(ns);
321 ctx->pid_ns = ns;
322 }
323
324 mnt = fc_mount(fc);
325 put_fs_context(fc);
326 if (IS_ERR(mnt))
327 return PTR_ERR(mnt);
328
329 ns->proc_mnt = mnt;
330 return 0;
331}
332
333void pid_ns_release_proc(struct pid_namespace *ns)
334{
335 kern_unmount(ns->proc_mnt);
336}
337
