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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/sched/signal.h>
3#include <linux/errno.h>
4#include <linux/dcache.h>
5#include <linux/path.h>
6#include <linux/fdtable.h>
7#include <linux/namei.h>
8#include <linux/pid.h>
9#include <linux/security.h>
10#include <linux/file.h>
11#include <linux/seq_file.h>
12#include <linux/fs.h>
13
14#include <linux/proc_fs.h>
15
16#include "../mount.h"
17#include "internal.h"
18#include "fd.h"
19
20static int seq_show(struct seq_file *m, void *v)
21{
22 struct files_struct *files = NULL;
23 int f_flags = 0, ret = -ENOENT;
24 struct file *file = NULL;
25 struct task_struct *task;
26
27 task = get_proc_task(m->private);
28 if (!task)
29 return -ENOENT;
30
31 files = get_files_struct(task);
32 put_task_struct(task);
33
34 if (files) {
35 unsigned int fd = proc_fd(m->private);
36
37 spin_lock(&files->file_lock);
38 file = fcheck_files(files, fd);
39 if (file) {
40 struct fdtable *fdt = files_fdtable(files);
41
42 f_flags = file->f_flags;
43 if (close_on_exec(fd, fdt))
44 f_flags |= O_CLOEXEC;
45
46 get_file(file);
47 ret = 0;
48 }
49 spin_unlock(&files->file_lock);
50 put_files_struct(files);
51 }
52
53 if (ret)
54 return ret;
55
56 seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n",
57 (long long)file->f_pos, f_flags,
58 real_mount(file->f_path.mnt)->mnt_id);
59
60 show_fd_locks(m, file, files);
61 if (seq_has_overflowed(m))
62 goto out;
63
64 if (file->f_op->show_fdinfo)
65 file->f_op->show_fdinfo(m, file);
66
67out:
68 fput(file);
69 return 0;
70}
71
72static int seq_fdinfo_open(struct inode *inode, struct file *file)
73{
74 return single_open(file, seq_show, inode);
75}
76
77static const struct file_operations proc_fdinfo_file_operations = {
78 .open = seq_fdinfo_open,
79 .read = seq_read,
80 .llseek = seq_lseek,
81 .release = single_release,
82};
83
84static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
85{
86 struct files_struct *files;
87 struct task_struct *task;
88 struct inode *inode;
89 unsigned int fd;
90
91 if (flags & LOOKUP_RCU)
92 return -ECHILD;
93
94 inode = d_inode(dentry);
95 task = get_proc_task(inode);
96 fd = proc_fd(inode);
97
98 if (task) {
99 files = get_files_struct(task);
100 if (files) {
101 struct file *file;
102
103 rcu_read_lock();
104 file = fcheck_files(files, fd);
105 if (file) {
106 unsigned f_mode = file->f_mode;
107
108 rcu_read_unlock();
109 put_files_struct(files);
110
111 task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
112
113 if (S_ISLNK(inode->i_mode)) {
114 unsigned i_mode = S_IFLNK;
115 if (f_mode & FMODE_READ)
116 i_mode |= S_IRUSR | S_IXUSR;
117 if (f_mode & FMODE_WRITE)
118 i_mode |= S_IWUSR | S_IXUSR;
119 inode->i_mode = i_mode;
120 }
121
122 security_task_to_inode(task, inode);
123 put_task_struct(task);
124 return 1;
125 }
126 rcu_read_unlock();
127 put_files_struct(files);
128 }
129 put_task_struct(task);
130 }
131 return 0;
132}
133
134static const struct dentry_operations tid_fd_dentry_operations = {
135 .d_revalidate = tid_fd_revalidate,
136 .d_delete = pid_delete_dentry,
137};
138
139static int proc_fd_link(struct dentry *dentry, struct path *path)
140{
141 struct files_struct *files = NULL;
142 struct task_struct *task;
143 int ret = -ENOENT;
144
145 task = get_proc_task(d_inode(dentry));
146 if (task) {
147 files = get_files_struct(task);
148 put_task_struct(task);
149 }
150
151 if (files) {
152 unsigned int fd = proc_fd(d_inode(dentry));
153 struct file *fd_file;
154
155 spin_lock(&files->file_lock);
156 fd_file = fcheck_files(files, fd);
157 if (fd_file) {
158 *path = fd_file->f_path;
159 path_get(&fd_file->f_path);
160 ret = 0;
161 }
162 spin_unlock(&files->file_lock);
163 put_files_struct(files);
164 }
165
166 return ret;
167}
168
169static int
170proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
171 struct task_struct *task, const void *ptr)
172{
173 unsigned fd = (unsigned long)ptr;
174 struct proc_inode *ei;
175 struct inode *inode;
176
177 inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK);
178 if (!inode)
179 goto out;
180
181 ei = PROC_I(inode);
182 ei->fd = fd;
183
184 inode->i_op = &proc_pid_link_inode_operations;
185 inode->i_size = 64;
186
187 ei->op.proc_get_link = proc_fd_link;
188
189 d_set_d_op(dentry, &tid_fd_dentry_operations);
190 d_add(dentry, inode);
191
192 /* Close the race of the process dying before we return the dentry */
193 if (tid_fd_revalidate(dentry, 0))
194 return 0;
195 out:
196 return -ENOENT;
197}
198
199static struct dentry *proc_lookupfd_common(struct inode *dir,
200 struct dentry *dentry,
201 instantiate_t instantiate)
202{
203 struct task_struct *task = get_proc_task(dir);
204 int result = -ENOENT;
205 unsigned fd = name_to_int(&dentry->d_name);
206
207 if (!task)
208 goto out_no_task;
209 if (fd == ~0U)
210 goto out;
211
212 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
213out:
214 put_task_struct(task);
215out_no_task:
216 return ERR_PTR(result);
217}
218
219static int proc_readfd_common(struct file *file, struct dir_context *ctx,
220 instantiate_t instantiate)
221{
222 struct task_struct *p = get_proc_task(file_inode(file));
223 struct files_struct *files;
224 unsigned int fd;
225
226 if (!p)
227 return -ENOENT;
228
229 if (!dir_emit_dots(file, ctx))
230 goto out;
231 files = get_files_struct(p);
232 if (!files)
233 goto out;
234
235 rcu_read_lock();
236 for (fd = ctx->pos - 2;
237 fd < files_fdtable(files)->max_fds;
238 fd++, ctx->pos++) {
239 char name[10 + 1];
240 int len;
241
242 if (!fcheck_files(files, fd))
243 continue;
244 rcu_read_unlock();
245
246 len = snprintf(name, sizeof(name), "%u", fd);
247 if (!proc_fill_cache(file, ctx,
248 name, len, instantiate, p,
249 (void *)(unsigned long)fd))
250 goto out_fd_loop;
251 cond_resched();
252 rcu_read_lock();
253 }
254 rcu_read_unlock();
255out_fd_loop:
256 put_files_struct(files);
257out:
258 put_task_struct(p);
259 return 0;
260}
261
262static int proc_readfd(struct file *file, struct dir_context *ctx)
263{
264 return proc_readfd_common(file, ctx, proc_fd_instantiate);
265}
266
267const struct file_operations proc_fd_operations = {
268 .read = generic_read_dir,
269 .iterate_shared = proc_readfd,
270 .llseek = generic_file_llseek,
271};
272
273static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
274 unsigned int flags)
275{
276 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
277}
278
279/*
280 * /proc/pid/fd needs a special permission handler so that a process can still
281 * access /proc/self/fd after it has executed a setuid().
282 */
283int proc_fd_permission(struct inode *inode, int mask)
284{
285 struct task_struct *p;
286 int rv;
287
288 rv = generic_permission(inode, mask);
289 if (rv == 0)
290 return rv;
291
292 rcu_read_lock();
293 p = pid_task(proc_pid(inode), PIDTYPE_PID);
294 if (p && same_thread_group(p, current))
295 rv = 0;
296 rcu_read_unlock();
297
298 return rv;
299}
300
301const struct inode_operations proc_fd_inode_operations = {
302 .lookup = proc_lookupfd,
303 .permission = proc_fd_permission,
304 .setattr = proc_setattr,
305};
306
307static int
308proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
309 struct task_struct *task, const void *ptr)
310{
311 unsigned fd = (unsigned long)ptr;
312 struct proc_inode *ei;
313 struct inode *inode;
314
315 inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR);
316 if (!inode)
317 goto out;
318
319 ei = PROC_I(inode);
320 ei->fd = fd;
321
322 inode->i_fop = &proc_fdinfo_file_operations;
323
324 d_set_d_op(dentry, &tid_fd_dentry_operations);
325 d_add(dentry, inode);
326
327 /* Close the race of the process dying before we return the dentry */
328 if (tid_fd_revalidate(dentry, 0))
329 return 0;
330 out:
331 return -ENOENT;
332}
333
334static struct dentry *
335proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
336{
337 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
338}
339
340static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
341{
342 return proc_readfd_common(file, ctx,
343 proc_fdinfo_instantiate);
344}
345
346const struct inode_operations proc_fdinfo_inode_operations = {
347 .lookup = proc_lookupfdinfo,
348 .setattr = proc_setattr,
349};
350
351const struct file_operations proc_fdinfo_operations = {
352 .read = generic_read_dir,
353 .iterate_shared = proc_readfdinfo,
354 .llseek = generic_file_llseek,
355};
1#include <linux/sched.h>
2#include <linux/errno.h>
3#include <linux/dcache.h>
4#include <linux/path.h>
5#include <linux/fdtable.h>
6#include <linux/namei.h>
7#include <linux/pid.h>
8#include <linux/security.h>
9#include <linux/file.h>
10#include <linux/seq_file.h>
11
12#include <linux/proc_fs.h>
13
14#include "../mount.h"
15#include "internal.h"
16#include "fd.h"
17
18static int seq_show(struct seq_file *m, void *v)
19{
20 struct files_struct *files = NULL;
21 int f_flags = 0, ret = -ENOENT;
22 struct file *file = NULL;
23 struct task_struct *task;
24
25 task = get_proc_task(m->private);
26 if (!task)
27 return -ENOENT;
28
29 files = get_files_struct(task);
30 put_task_struct(task);
31
32 if (files) {
33 int fd = proc_fd(m->private);
34
35 spin_lock(&files->file_lock);
36 file = fcheck_files(files, fd);
37 if (file) {
38 struct fdtable *fdt = files_fdtable(files);
39
40 f_flags = file->f_flags;
41 if (close_on_exec(fd, fdt))
42 f_flags |= O_CLOEXEC;
43
44 get_file(file);
45 ret = 0;
46 }
47 spin_unlock(&files->file_lock);
48 put_files_struct(files);
49 }
50
51 if (!ret) {
52 seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n",
53 (long long)file->f_pos, f_flags,
54 real_mount(file->f_path.mnt)->mnt_id);
55 if (file->f_op->show_fdinfo)
56 ret = file->f_op->show_fdinfo(m, file);
57 fput(file);
58 }
59
60 return ret;
61}
62
63static int seq_fdinfo_open(struct inode *inode, struct file *file)
64{
65 return single_open(file, seq_show, inode);
66}
67
68static const struct file_operations proc_fdinfo_file_operations = {
69 .open = seq_fdinfo_open,
70 .read = seq_read,
71 .llseek = seq_lseek,
72 .release = single_release,
73};
74
75static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
76{
77 struct files_struct *files;
78 struct task_struct *task;
79 const struct cred *cred;
80 struct inode *inode;
81 int fd;
82
83 if (flags & LOOKUP_RCU)
84 return -ECHILD;
85
86 inode = dentry->d_inode;
87 task = get_proc_task(inode);
88 fd = proc_fd(inode);
89
90 if (task) {
91 files = get_files_struct(task);
92 if (files) {
93 struct file *file;
94
95 rcu_read_lock();
96 file = fcheck_files(files, fd);
97 if (file) {
98 unsigned f_mode = file->f_mode;
99
100 rcu_read_unlock();
101 put_files_struct(files);
102
103 if (task_dumpable(task)) {
104 rcu_read_lock();
105 cred = __task_cred(task);
106 inode->i_uid = cred->euid;
107 inode->i_gid = cred->egid;
108 rcu_read_unlock();
109 } else {
110 inode->i_uid = GLOBAL_ROOT_UID;
111 inode->i_gid = GLOBAL_ROOT_GID;
112 }
113
114 if (S_ISLNK(inode->i_mode)) {
115 unsigned i_mode = S_IFLNK;
116 if (f_mode & FMODE_READ)
117 i_mode |= S_IRUSR | S_IXUSR;
118 if (f_mode & FMODE_WRITE)
119 i_mode |= S_IWUSR | S_IXUSR;
120 inode->i_mode = i_mode;
121 }
122
123 security_task_to_inode(task, inode);
124 put_task_struct(task);
125 return 1;
126 }
127 rcu_read_unlock();
128 put_files_struct(files);
129 }
130 put_task_struct(task);
131 }
132
133 d_drop(dentry);
134 return 0;
135}
136
137static const struct dentry_operations tid_fd_dentry_operations = {
138 .d_revalidate = tid_fd_revalidate,
139 .d_delete = pid_delete_dentry,
140};
141
142static int proc_fd_link(struct dentry *dentry, struct path *path)
143{
144 struct files_struct *files = NULL;
145 struct task_struct *task;
146 int ret = -ENOENT;
147
148 task = get_proc_task(dentry->d_inode);
149 if (task) {
150 files = get_files_struct(task);
151 put_task_struct(task);
152 }
153
154 if (files) {
155 int fd = proc_fd(dentry->d_inode);
156 struct file *fd_file;
157
158 spin_lock(&files->file_lock);
159 fd_file = fcheck_files(files, fd);
160 if (fd_file) {
161 *path = fd_file->f_path;
162 path_get(&fd_file->f_path);
163 ret = 0;
164 }
165 spin_unlock(&files->file_lock);
166 put_files_struct(files);
167 }
168
169 return ret;
170}
171
172static int
173proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
174 struct task_struct *task, const void *ptr)
175{
176 unsigned fd = (unsigned long)ptr;
177 struct proc_inode *ei;
178 struct inode *inode;
179
180 inode = proc_pid_make_inode(dir->i_sb, task);
181 if (!inode)
182 goto out;
183
184 ei = PROC_I(inode);
185 ei->fd = fd;
186
187 inode->i_mode = S_IFLNK;
188 inode->i_op = &proc_pid_link_inode_operations;
189 inode->i_size = 64;
190
191 ei->op.proc_get_link = proc_fd_link;
192
193 d_set_d_op(dentry, &tid_fd_dentry_operations);
194 d_add(dentry, inode);
195
196 /* Close the race of the process dying before we return the dentry */
197 if (tid_fd_revalidate(dentry, 0))
198 return 0;
199 out:
200 return -ENOENT;
201}
202
203static struct dentry *proc_lookupfd_common(struct inode *dir,
204 struct dentry *dentry,
205 instantiate_t instantiate)
206{
207 struct task_struct *task = get_proc_task(dir);
208 int result = -ENOENT;
209 unsigned fd = name_to_int(dentry);
210
211 if (!task)
212 goto out_no_task;
213 if (fd == ~0U)
214 goto out;
215
216 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
217out:
218 put_task_struct(task);
219out_no_task:
220 return ERR_PTR(result);
221}
222
223static int proc_readfd_common(struct file *file, struct dir_context *ctx,
224 instantiate_t instantiate)
225{
226 struct task_struct *p = get_proc_task(file_inode(file));
227 struct files_struct *files;
228 unsigned int fd;
229
230 if (!p)
231 return -ENOENT;
232
233 if (!dir_emit_dots(file, ctx))
234 goto out;
235 files = get_files_struct(p);
236 if (!files)
237 goto out;
238
239 rcu_read_lock();
240 for (fd = ctx->pos - 2;
241 fd < files_fdtable(files)->max_fds;
242 fd++, ctx->pos++) {
243 char name[PROC_NUMBUF];
244 int len;
245
246 if (!fcheck_files(files, fd))
247 continue;
248 rcu_read_unlock();
249
250 len = snprintf(name, sizeof(name), "%d", fd);
251 if (!proc_fill_cache(file, ctx,
252 name, len, instantiate, p,
253 (void *)(unsigned long)fd))
254 goto out_fd_loop;
255 rcu_read_lock();
256 }
257 rcu_read_unlock();
258out_fd_loop:
259 put_files_struct(files);
260out:
261 put_task_struct(p);
262 return 0;
263}
264
265static int proc_readfd(struct file *file, struct dir_context *ctx)
266{
267 return proc_readfd_common(file, ctx, proc_fd_instantiate);
268}
269
270const struct file_operations proc_fd_operations = {
271 .read = generic_read_dir,
272 .iterate = proc_readfd,
273 .llseek = default_llseek,
274};
275
276static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
277 unsigned int flags)
278{
279 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
280}
281
282/*
283 * /proc/pid/fd needs a special permission handler so that a process can still
284 * access /proc/self/fd after it has executed a setuid().
285 */
286int proc_fd_permission(struct inode *inode, int mask)
287{
288 int rv = generic_permission(inode, mask);
289 if (rv == 0)
290 return 0;
291 if (task_tgid(current) == proc_pid(inode))
292 rv = 0;
293 return rv;
294}
295
296const struct inode_operations proc_fd_inode_operations = {
297 .lookup = proc_lookupfd,
298 .permission = proc_fd_permission,
299 .setattr = proc_setattr,
300};
301
302static int
303proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
304 struct task_struct *task, const void *ptr)
305{
306 unsigned fd = (unsigned long)ptr;
307 struct proc_inode *ei;
308 struct inode *inode;
309
310 inode = proc_pid_make_inode(dir->i_sb, task);
311 if (!inode)
312 goto out;
313
314 ei = PROC_I(inode);
315 ei->fd = fd;
316
317 inode->i_mode = S_IFREG | S_IRUSR;
318 inode->i_fop = &proc_fdinfo_file_operations;
319
320 d_set_d_op(dentry, &tid_fd_dentry_operations);
321 d_add(dentry, inode);
322
323 /* Close the race of the process dying before we return the dentry */
324 if (tid_fd_revalidate(dentry, 0))
325 return 0;
326 out:
327 return -ENOENT;
328}
329
330static struct dentry *
331proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
332{
333 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
334}
335
336static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
337{
338 return proc_readfd_common(file, ctx,
339 proc_fdinfo_instantiate);
340}
341
342const struct inode_operations proc_fdinfo_inode_operations = {
343 .lookup = proc_lookupfdinfo,
344 .setattr = proc_setattr,
345};
346
347const struct file_operations proc_fdinfo_operations = {
348 .read = generic_read_dir,
349 .iterate = proc_readfdinfo,
350 .llseek = default_llseek,
351};