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