Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
3f07c014 | 2 | #include <linux/sched/signal.h> |
faf60af1 CG |
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> | |
7bc3fa01 | 9 | #include <linux/ptrace.h> |
f1f1f256 | 10 | #include <linux/bitmap.h> |
faf60af1 | 11 | #include <linux/security.h> |
ddd3e077 CG |
12 | #include <linux/file.h> |
13 | #include <linux/seq_file.h> | |
6c8c9031 | 14 | #include <linux/fs.h> |
faf60af1 CG |
15 | |
16 | #include <linux/proc_fs.h> | |
17 | ||
49d063cb | 18 | #include "../mount.h" |
faf60af1 CG |
19 | #include "internal.h" |
20 | #include "fd.h" | |
21 | ||
ddd3e077 | 22 | static int seq_show(struct seq_file *m, void *v) |
faf60af1 | 23 | { |
faf60af1 | 24 | struct files_struct *files = NULL; |
ddd3e077 CG |
25 | int f_flags = 0, ret = -ENOENT; |
26 | struct file *file = NULL; | |
27 | struct task_struct *task; | |
28 | ||
29 | task = get_proc_task(m->private); | |
30 | if (!task) | |
31 | return -ENOENT; | |
32 | ||
775e0656 EB |
33 | task_lock(task); |
34 | files = task->files; | |
faf60af1 | 35 | if (files) { |
771187d6 | 36 | unsigned int fd = proc_fd(m->private); |
ddd3e077 | 37 | |
faf60af1 | 38 | spin_lock(&files->file_lock); |
120ce2b0 | 39 | file = files_lookup_fd_locked(files, fd); |
faf60af1 | 40 | if (file) { |
ddd3e077 | 41 | struct fdtable *fdt = files_fdtable(files); |
faf60af1 | 42 | |
c6f3d811 | 43 | f_flags = file->f_flags; |
faf60af1 CG |
44 | if (close_on_exec(fd, fdt)) |
45 | f_flags |= O_CLOEXEC; | |
46 | ||
ddd3e077 CG |
47 | get_file(file); |
48 | ret = 0; | |
faf60af1 CG |
49 | } |
50 | spin_unlock(&files->file_lock); | |
faf60af1 | 51 | } |
775e0656 EB |
52 | task_unlock(task); |
53 | put_task_struct(task); | |
ddd3e077 | 54 | |
6c8c9031 AV |
55 | if (ret) |
56 | return ret; | |
57 | ||
3845f256 | 58 | seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n", |
6c8c9031 | 59 | (long long)file->f_pos, f_flags, |
3845f256 KS |
60 | real_mount(file->f_path.mnt)->mnt_id, |
61 | file_inode(file)->i_ino); | |
6c8c9031 | 62 | |
775e0656 | 63 | /* show_fd_locks() never deferences files so a stale value is safe */ |
6c8c9031 AV |
64 | show_fd_locks(m, file, files); |
65 | if (seq_has_overflowed(m)) | |
66 | goto out; | |
67 | ||
68 | if (file->f_op->show_fdinfo) | |
69 | file->f_op->show_fdinfo(m, file); | |
ddd3e077 | 70 | |
6c8c9031 AV |
71 | out: |
72 | fput(file); | |
73 | return 0; | |
faf60af1 CG |
74 | } |
75 | ||
1927e498 | 76 | static int proc_fdinfo_access_allowed(struct inode *inode) |
ddd3e077 | 77 | { |
7bc3fa01 KS |
78 | bool allowed = false; |
79 | struct task_struct *task = get_proc_task(inode); | |
80 | ||
81 | if (!task) | |
82 | return -ESRCH; | |
83 | ||
84 | allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS); | |
85 | put_task_struct(task); | |
86 | ||
87 | if (!allowed) | |
88 | return -EACCES; | |
89 | ||
1927e498 KS |
90 | return 0; |
91 | } | |
92 | ||
93 | static int seq_fdinfo_open(struct inode *inode, struct file *file) | |
94 | { | |
95 | int ret = proc_fdinfo_access_allowed(inode); | |
96 | ||
97 | if (ret) | |
98 | return ret; | |
99 | ||
ddd3e077 CG |
100 | return single_open(file, seq_show, inode); |
101 | } | |
102 | ||
103 | static const struct file_operations proc_fdinfo_file_operations = { | |
104 | .open = seq_fdinfo_open, | |
105 | .read = seq_read, | |
106 | .llseek = seq_lseek, | |
107 | .release = single_release, | |
108 | }; | |
109 | ||
1ae9bd8b AV |
110 | static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode) |
111 | { | |
1ae9bd8b AV |
112 | struct file *file; |
113 | ||
1ae9bd8b | 114 | rcu_read_lock(); |
64eb661f | 115 | file = task_lookup_fd_rcu(task, fd); |
1ae9bd8b AV |
116 | if (file) |
117 | *mode = file->f_mode; | |
118 | rcu_read_unlock(); | |
1ae9bd8b AV |
119 | return !!file; |
120 | } | |
121 | ||
98836386 AV |
122 | static void tid_fd_update_inode(struct task_struct *task, struct inode *inode, |
123 | fmode_t f_mode) | |
124 | { | |
125 | task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); | |
126 | ||
127 | if (S_ISLNK(inode->i_mode)) { | |
128 | unsigned i_mode = S_IFLNK; | |
129 | if (f_mode & FMODE_READ) | |
130 | i_mode |= S_IRUSR | S_IXUSR; | |
131 | if (f_mode & FMODE_WRITE) | |
132 | i_mode |= S_IWUSR | S_IXUSR; | |
133 | inode->i_mode = i_mode; | |
134 | } | |
135 | security_task_to_inode(task, inode); | |
136 | } | |
137 | ||
faf60af1 CG |
138 | static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) |
139 | { | |
faf60af1 | 140 | struct task_struct *task; |
faf60af1 | 141 | struct inode *inode; |
771187d6 | 142 | unsigned int fd; |
faf60af1 CG |
143 | |
144 | if (flags & LOOKUP_RCU) | |
145 | return -ECHILD; | |
146 | ||
2b0143b5 | 147 | inode = d_inode(dentry); |
faf60af1 CG |
148 | task = get_proc_task(inode); |
149 | fd = proc_fd(inode); | |
150 | ||
151 | if (task) { | |
98836386 | 152 | fmode_t f_mode; |
1ae9bd8b | 153 | if (tid_fd_mode(task, fd, &f_mode)) { |
98836386 | 154 | tid_fd_update_inode(task, inode, f_mode); |
1ae9bd8b AV |
155 | put_task_struct(task); |
156 | return 1; | |
faf60af1 CG |
157 | } |
158 | put_task_struct(task); | |
159 | } | |
faf60af1 CG |
160 | return 0; |
161 | } | |
162 | ||
163 | static const struct dentry_operations tid_fd_dentry_operations = { | |
164 | .d_revalidate = tid_fd_revalidate, | |
165 | .d_delete = pid_delete_dentry, | |
166 | }; | |
167 | ||
168 | static int proc_fd_link(struct dentry *dentry, struct path *path) | |
169 | { | |
ddd3e077 CG |
170 | struct task_struct *task; |
171 | int ret = -ENOENT; | |
172 | ||
2b0143b5 | 173 | task = get_proc_task(d_inode(dentry)); |
ddd3e077 | 174 | if (task) { |
771187d6 | 175 | unsigned int fd = proc_fd(d_inode(dentry)); |
ddd3e077 CG |
176 | struct file *fd_file; |
177 | ||
439be326 | 178 | fd_file = fget_task(task, fd); |
ddd3e077 CG |
179 | if (fd_file) { |
180 | *path = fd_file->f_path; | |
181 | path_get(&fd_file->f_path); | |
182 | ret = 0; | |
439be326 | 183 | fput(fd_file); |
ddd3e077 | 184 | } |
439be326 | 185 | put_task_struct(task); |
ddd3e077 CG |
186 | } |
187 | ||
188 | return ret; | |
faf60af1 CG |
189 | } |
190 | ||
98836386 AV |
191 | struct fd_data { |
192 | fmode_t mode; | |
193 | unsigned fd; | |
194 | }; | |
195 | ||
0168b9e3 AV |
196 | static struct dentry *proc_fd_instantiate(struct dentry *dentry, |
197 | struct task_struct *task, const void *ptr) | |
faf60af1 | 198 | { |
98836386 | 199 | const struct fd_data *data = ptr; |
faf60af1 CG |
200 | struct proc_inode *ei; |
201 | struct inode *inode; | |
202 | ||
0168b9e3 | 203 | inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK); |
faf60af1 | 204 | if (!inode) |
0168b9e3 | 205 | return ERR_PTR(-ENOENT); |
faf60af1 CG |
206 | |
207 | ei = PROC_I(inode); | |
98836386 | 208 | ei->fd = data->fd; |
faf60af1 | 209 | |
faf60af1 CG |
210 | inode->i_op = &proc_pid_link_inode_operations; |
211 | inode->i_size = 64; | |
212 | ||
213 | ei->op.proc_get_link = proc_fd_link; | |
98836386 | 214 | tid_fd_update_inode(task, inode, data->mode); |
faf60af1 CG |
215 | |
216 | d_set_d_op(dentry, &tid_fd_dentry_operations); | |
0168b9e3 | 217 | return d_splice_alias(inode, dentry); |
faf60af1 CG |
218 | } |
219 | ||
220 | static struct dentry *proc_lookupfd_common(struct inode *dir, | |
221 | struct dentry *dentry, | |
222 | instantiate_t instantiate) | |
223 | { | |
224 | struct task_struct *task = get_proc_task(dir); | |
98836386 | 225 | struct fd_data data = {.fd = name_to_int(&dentry->d_name)}; |
0168b9e3 | 226 | struct dentry *result = ERR_PTR(-ENOENT); |
faf60af1 CG |
227 | |
228 | if (!task) | |
229 | goto out_no_task; | |
98836386 | 230 | if (data.fd == ~0U) |
faf60af1 | 231 | goto out; |
98836386 | 232 | if (!tid_fd_mode(task, data.fd, &data.mode)) |
1ae9bd8b | 233 | goto out; |
faf60af1 | 234 | |
0168b9e3 | 235 | result = instantiate(dentry, task, &data); |
faf60af1 CG |
236 | out: |
237 | put_task_struct(task); | |
238 | out_no_task: | |
0168b9e3 | 239 | return result; |
faf60af1 CG |
240 | } |
241 | ||
f0c3b509 AV |
242 | static int proc_readfd_common(struct file *file, struct dir_context *ctx, |
243 | instantiate_t instantiate) | |
faf60af1 | 244 | { |
f0c3b509 | 245 | struct task_struct *p = get_proc_task(file_inode(file)); |
f0c3b509 | 246 | unsigned int fd; |
faf60af1 | 247 | |
faf60af1 | 248 | if (!p) |
f0c3b509 | 249 | return -ENOENT; |
faf60af1 | 250 | |
f0c3b509 AV |
251 | if (!dir_emit_dots(file, ctx)) |
252 | goto out; | |
f0c3b509 AV |
253 | |
254 | rcu_read_lock(); | |
5b17b618 | 255 | for (fd = ctx->pos - 2;; fd++) { |
98836386 AV |
256 | struct file *f; |
257 | struct fd_data data; | |
e3912ac3 | 258 | char name[10 + 1]; |
a4ef3895 | 259 | unsigned int len; |
f0c3b509 | 260 | |
5b17b618 EB |
261 | f = task_lookup_next_fd_rcu(p, &fd); |
262 | ctx->pos = fd + 2LL; | |
98836386 | 263 | if (!f) |
5b17b618 | 264 | break; |
98836386 | 265 | data.mode = f->f_mode; |
f0c3b509 | 266 | rcu_read_unlock(); |
98836386 | 267 | data.fd = fd; |
f0c3b509 | 268 | |
771187d6 | 269 | len = snprintf(name, sizeof(name), "%u", fd); |
f0c3b509 AV |
270 | if (!proc_fill_cache(file, ctx, |
271 | name, len, instantiate, p, | |
98836386 | 272 | &data)) |
5b17b618 | 273 | goto out; |
3cc4a84e | 274 | cond_resched(); |
f0c3b509 | 275 | rcu_read_lock(); |
faf60af1 | 276 | } |
f0c3b509 | 277 | rcu_read_unlock(); |
faf60af1 CG |
278 | out: |
279 | put_task_struct(p); | |
f0c3b509 | 280 | return 0; |
faf60af1 CG |
281 | } |
282 | ||
f1f1f256 IB |
283 | static int proc_readfd_count(struct inode *inode, loff_t *count) |
284 | { | |
285 | struct task_struct *p = get_proc_task(inode); | |
286 | struct fdtable *fdt; | |
287 | ||
288 | if (!p) | |
289 | return -ENOENT; | |
290 | ||
291 | task_lock(p); | |
292 | if (p->files) { | |
293 | rcu_read_lock(); | |
294 | ||
295 | fdt = files_fdtable(p->files); | |
296 | *count = bitmap_weight(fdt->open_fds, fdt->max_fds); | |
297 | ||
298 | rcu_read_unlock(); | |
299 | } | |
300 | task_unlock(p); | |
301 | ||
302 | put_task_struct(p); | |
303 | ||
304 | return 0; | |
305 | } | |
306 | ||
f0c3b509 | 307 | static int proc_readfd(struct file *file, struct dir_context *ctx) |
faf60af1 | 308 | { |
f0c3b509 | 309 | return proc_readfd_common(file, ctx, proc_fd_instantiate); |
faf60af1 CG |
310 | } |
311 | ||
312 | const struct file_operations proc_fd_operations = { | |
313 | .read = generic_read_dir, | |
f50752ea AV |
314 | .iterate_shared = proc_readfd, |
315 | .llseek = generic_file_llseek, | |
faf60af1 CG |
316 | }; |
317 | ||
318 | static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry, | |
319 | unsigned int flags) | |
320 | { | |
321 | return proc_lookupfd_common(dir, dentry, proc_fd_instantiate); | |
322 | } | |
323 | ||
324 | /* | |
325 | * /proc/pid/fd needs a special permission handler so that a process can still | |
326 | * access /proc/self/fd after it has executed a setuid(). | |
327 | */ | |
549c7297 CB |
328 | int proc_fd_permission(struct user_namespace *mnt_userns, |
329 | struct inode *inode, int mask) | |
faf60af1 | 330 | { |
54708d28 ON |
331 | struct task_struct *p; |
332 | int rv; | |
333 | ||
47291baa | 334 | rv = generic_permission(&init_user_ns, inode, mask); |
faf60af1 | 335 | if (rv == 0) |
54708d28 ON |
336 | return rv; |
337 | ||
338 | rcu_read_lock(); | |
339 | p = pid_task(proc_pid(inode), PIDTYPE_PID); | |
340 | if (p && same_thread_group(p, current)) | |
faf60af1 | 341 | rv = 0; |
54708d28 ON |
342 | rcu_read_unlock(); |
343 | ||
faf60af1 CG |
344 | return rv; |
345 | } | |
346 | ||
b74d24f7 | 347 | static int proc_fd_getattr(struct mnt_idmap *idmap, |
f1f1f256 IB |
348 | const struct path *path, struct kstat *stat, |
349 | u32 request_mask, unsigned int query_flags) | |
350 | { | |
351 | struct inode *inode = d_inode(path->dentry); | |
352 | int rv = 0; | |
353 | ||
b74d24f7 | 354 | generic_fillattr(&nop_mnt_idmap, inode, stat); |
f1f1f256 IB |
355 | |
356 | /* If it's a directory, put the number of open fds there */ | |
357 | if (S_ISDIR(inode->i_mode)) { | |
358 | rv = proc_readfd_count(inode, &stat->size); | |
359 | if (rv < 0) | |
360 | return rv; | |
361 | } | |
362 | ||
363 | return rv; | |
364 | } | |
365 | ||
faf60af1 CG |
366 | const struct inode_operations proc_fd_inode_operations = { |
367 | .lookup = proc_lookupfd, | |
368 | .permission = proc_fd_permission, | |
f1f1f256 | 369 | .getattr = proc_fd_getattr, |
faf60af1 CG |
370 | .setattr = proc_setattr, |
371 | }; | |
372 | ||
0168b9e3 AV |
373 | static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, |
374 | struct task_struct *task, const void *ptr) | |
faf60af1 | 375 | { |
98836386 | 376 | const struct fd_data *data = ptr; |
faf60af1 CG |
377 | struct proc_inode *ei; |
378 | struct inode *inode; | |
379 | ||
7bc3fa01 | 380 | inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO); |
faf60af1 | 381 | if (!inode) |
0168b9e3 | 382 | return ERR_PTR(-ENOENT); |
faf60af1 CG |
383 | |
384 | ei = PROC_I(inode); | |
98836386 | 385 | ei->fd = data->fd; |
faf60af1 | 386 | |
faf60af1 | 387 | inode->i_fop = &proc_fdinfo_file_operations; |
98836386 | 388 | tid_fd_update_inode(task, inode, 0); |
faf60af1 CG |
389 | |
390 | d_set_d_op(dentry, &tid_fd_dentry_operations); | |
0168b9e3 | 391 | return d_splice_alias(inode, dentry); |
faf60af1 CG |
392 | } |
393 | ||
394 | static struct dentry * | |
395 | proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
396 | { | |
397 | return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate); | |
398 | } | |
399 | ||
f0c3b509 | 400 | static int proc_readfdinfo(struct file *file, struct dir_context *ctx) |
faf60af1 | 401 | { |
f0c3b509 | 402 | return proc_readfd_common(file, ctx, |
faf60af1 CG |
403 | proc_fdinfo_instantiate); |
404 | } | |
405 | ||
1927e498 KS |
406 | static int proc_open_fdinfo(struct inode *inode, struct file *file) |
407 | { | |
408 | int ret = proc_fdinfo_access_allowed(inode); | |
409 | ||
410 | if (ret) | |
411 | return ret; | |
412 | ||
413 | return 0; | |
414 | } | |
415 | ||
faf60af1 CG |
416 | const struct inode_operations proc_fdinfo_inode_operations = { |
417 | .lookup = proc_lookupfdinfo, | |
418 | .setattr = proc_setattr, | |
419 | }; | |
420 | ||
421 | const struct file_operations proc_fdinfo_operations = { | |
1927e498 | 422 | .open = proc_open_fdinfo, |
faf60af1 | 423 | .read = generic_read_dir, |
f50752ea AV |
424 | .iterate_shared = proc_readfdinfo, |
425 | .llseek = generic_file_llseek, | |
faf60af1 | 426 | }; |