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