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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#include <linux/fs.h>
12
13#include <linux/proc_fs.h>
14
15#include "../mount.h"
16#include "internal.h"
17#include "fd.h"
18
19static int seq_show(struct seq_file *m, void *v)
20{
21 struct files_struct *files = NULL;
22 int f_flags = 0, ret = -ENOENT;
23 struct file *file = NULL;
24 struct task_struct *task;
25
26 task = get_proc_task(m->private);
27 if (!task)
28 return -ENOENT;
29
30 files = get_files_struct(task);
31 put_task_struct(task);
32
33 if (files) {
34 unsigned int fd = proc_fd(m->private);
35
36 spin_lock(&files->file_lock);
37 file = fcheck_files(files, fd);
38 if (file) {
39 struct fdtable *fdt = files_fdtable(files);
40
41 f_flags = file->f_flags;
42 if (close_on_exec(fd, fdt))
43 f_flags |= O_CLOEXEC;
44
45 get_file(file);
46 ret = 0;
47 }
48 spin_unlock(&files->file_lock);
49 put_files_struct(files);
50 }
51
52 if (ret)
53 return ret;
54
55 seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n",
56 (long long)file->f_pos, f_flags,
57 real_mount(file->f_path.mnt)->mnt_id);
58
59 show_fd_locks(m, file, files);
60 if (seq_has_overflowed(m))
61 goto out;
62
63 if (file->f_op->show_fdinfo)
64 file->f_op->show_fdinfo(m, file);
65
66out:
67 fput(file);
68 return 0;
69}
70
71static int seq_fdinfo_open(struct inode *inode, struct file *file)
72{
73 return single_open(file, seq_show, inode);
74}
75
76static const struct file_operations proc_fdinfo_file_operations = {
77 .open = seq_fdinfo_open,
78 .read = seq_read,
79 .llseek = seq_lseek,
80 .release = single_release,
81};
82
83static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
84{
85 struct files_struct *files;
86 struct task_struct *task;
87 const struct cred *cred;
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 if (task_dumpable(task)) {
112 rcu_read_lock();
113 cred = __task_cred(task);
114 inode->i_uid = cred->euid;
115 inode->i_gid = cred->egid;
116 rcu_read_unlock();
117 } else {
118 inode->i_uid = GLOBAL_ROOT_UID;
119 inode->i_gid = GLOBAL_ROOT_GID;
120 }
121
122 if (S_ISLNK(inode->i_mode)) {
123 unsigned i_mode = S_IFLNK;
124 if (f_mode & FMODE_READ)
125 i_mode |= S_IRUSR | S_IXUSR;
126 if (f_mode & FMODE_WRITE)
127 i_mode |= S_IWUSR | S_IXUSR;
128 inode->i_mode = i_mode;
129 }
130
131 security_task_to_inode(task, inode);
132 put_task_struct(task);
133 return 1;
134 }
135 rcu_read_unlock();
136 put_files_struct(files);
137 }
138 put_task_struct(task);
139 }
140 return 0;
141}
142
143static const struct dentry_operations tid_fd_dentry_operations = {
144 .d_revalidate = tid_fd_revalidate,
145 .d_delete = pid_delete_dentry,
146};
147
148static int proc_fd_link(struct dentry *dentry, struct path *path)
149{
150 struct files_struct *files = NULL;
151 struct task_struct *task;
152 int ret = -ENOENT;
153
154 task = get_proc_task(d_inode(dentry));
155 if (task) {
156 files = get_files_struct(task);
157 put_task_struct(task);
158 }
159
160 if (files) {
161 unsigned int fd = proc_fd(d_inode(dentry));
162 struct file *fd_file;
163
164 spin_lock(&files->file_lock);
165 fd_file = fcheck_files(files, fd);
166 if (fd_file) {
167 *path = fd_file->f_path;
168 path_get(&fd_file->f_path);
169 ret = 0;
170 }
171 spin_unlock(&files->file_lock);
172 put_files_struct(files);
173 }
174
175 return ret;
176}
177
178static int
179proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
180 struct task_struct *task, const void *ptr)
181{
182 unsigned fd = (unsigned long)ptr;
183 struct proc_inode *ei;
184 struct inode *inode;
185
186 inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK);
187 if (!inode)
188 goto out;
189
190 ei = PROC_I(inode);
191 ei->fd = fd;
192
193 inode->i_op = &proc_pid_link_inode_operations;
194 inode->i_size = 64;
195
196 ei->op.proc_get_link = proc_fd_link;
197
198 d_set_d_op(dentry, &tid_fd_dentry_operations);
199 d_add(dentry, inode);
200
201 /* Close the race of the process dying before we return the dentry */
202 if (tid_fd_revalidate(dentry, 0))
203 return 0;
204 out:
205 return -ENOENT;
206}
207
208static struct dentry *proc_lookupfd_common(struct inode *dir,
209 struct dentry *dentry,
210 instantiate_t instantiate)
211{
212 struct task_struct *task = get_proc_task(dir);
213 int result = -ENOENT;
214 unsigned fd = name_to_int(&dentry->d_name);
215
216 if (!task)
217 goto out_no_task;
218 if (fd == ~0U)
219 goto out;
220
221 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
222out:
223 put_task_struct(task);
224out_no_task:
225 return ERR_PTR(result);
226}
227
228static int proc_readfd_common(struct file *file, struct dir_context *ctx,
229 instantiate_t instantiate)
230{
231 struct task_struct *p = get_proc_task(file_inode(file));
232 struct files_struct *files;
233 unsigned int fd;
234
235 if (!p)
236 return -ENOENT;
237
238 if (!dir_emit_dots(file, ctx))
239 goto out;
240 files = get_files_struct(p);
241 if (!files)
242 goto out;
243
244 rcu_read_lock();
245 for (fd = ctx->pos - 2;
246 fd < files_fdtable(files)->max_fds;
247 fd++, ctx->pos++) {
248 char name[PROC_NUMBUF];
249 int len;
250
251 if (!fcheck_files(files, fd))
252 continue;
253 rcu_read_unlock();
254
255 len = snprintf(name, sizeof(name), "%u", fd);
256 if (!proc_fill_cache(file, ctx,
257 name, len, instantiate, p,
258 (void *)(unsigned long)fd))
259 goto out_fd_loop;
260 cond_resched();
261 rcu_read_lock();
262 }
263 rcu_read_unlock();
264out_fd_loop:
265 put_files_struct(files);
266out:
267 put_task_struct(p);
268 return 0;
269}
270
271static int proc_readfd(struct file *file, struct dir_context *ctx)
272{
273 return proc_readfd_common(file, ctx, proc_fd_instantiate);
274}
275
276const struct file_operations proc_fd_operations = {
277 .read = generic_read_dir,
278 .iterate_shared = proc_readfd,
279 .llseek = generic_file_llseek,
280};
281
282static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
283 unsigned int flags)
284{
285 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
286}
287
288/*
289 * /proc/pid/fd needs a special permission handler so that a process can still
290 * access /proc/self/fd after it has executed a setuid().
291 */
292int proc_fd_permission(struct inode *inode, int mask)
293{
294 struct task_struct *p;
295 int rv;
296
297 rv = generic_permission(inode, mask);
298 if (rv == 0)
299 return rv;
300
301 rcu_read_lock();
302 p = pid_task(proc_pid(inode), PIDTYPE_PID);
303 if (p && same_thread_group(p, current))
304 rv = 0;
305 rcu_read_unlock();
306
307 return rv;
308}
309
310const struct inode_operations proc_fd_inode_operations = {
311 .lookup = proc_lookupfd,
312 .permission = proc_fd_permission,
313 .setattr = proc_setattr,
314};
315
316static int
317proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
318 struct task_struct *task, const void *ptr)
319{
320 unsigned fd = (unsigned long)ptr;
321 struct proc_inode *ei;
322 struct inode *inode;
323
324 inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR);
325 if (!inode)
326 goto out;
327
328 ei = PROC_I(inode);
329 ei->fd = fd;
330
331 inode->i_fop = &proc_fdinfo_file_operations;
332
333 d_set_d_op(dentry, &tid_fd_dentry_operations);
334 d_add(dentry, inode);
335
336 /* Close the race of the process dying before we return the dentry */
337 if (tid_fd_revalidate(dentry, 0))
338 return 0;
339 out:
340 return -ENOENT;
341}
342
343static struct dentry *
344proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
345{
346 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
347}
348
349static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
350{
351 return proc_readfd_common(file, ctx,
352 proc_fdinfo_instantiate);
353}
354
355const struct inode_operations proc_fdinfo_inode_operations = {
356 .lookup = proc_lookupfdinfo,
357 .setattr = proc_setattr,
358};
359
360const struct file_operations proc_fdinfo_operations = {
361 .read = generic_read_dir,
362 .iterate_shared = proc_readfdinfo,
363 .llseek = generic_file_llseek,
364};