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> | |
9 | #include <linux/security.h> | |
ddd3e077 CG |
10 | #include <linux/file.h> |
11 | #include <linux/seq_file.h> | |
6c8c9031 | 12 | #include <linux/fs.h> |
faf60af1 CG |
13 | |
14 | #include <linux/proc_fs.h> | |
15 | ||
49d063cb | 16 | #include "../mount.h" |
faf60af1 CG |
17 | #include "internal.h" |
18 | #include "fd.h" | |
19 | ||
ddd3e077 | 20 | static int seq_show(struct seq_file *m, void *v) |
faf60af1 | 21 | { |
faf60af1 | 22 | struct files_struct *files = NULL; |
ddd3e077 CG |
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); | |
faf60af1 | 33 | |
faf60af1 | 34 | if (files) { |
771187d6 | 35 | unsigned int fd = proc_fd(m->private); |
ddd3e077 | 36 | |
faf60af1 CG |
37 | spin_lock(&files->file_lock); |
38 | file = fcheck_files(files, fd); | |
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); | |
50 | put_files_struct(files); | |
51 | } | |
ddd3e077 | 52 | |
6c8c9031 AV |
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); | |
ddd3e077 | 66 | |
6c8c9031 AV |
67 | out: |
68 | fput(file); | |
69 | return 0; | |
faf60af1 CG |
70 | } |
71 | ||
ddd3e077 CG |
72 | static int seq_fdinfo_open(struct inode *inode, struct file *file) |
73 | { | |
74 | return single_open(file, seq_show, inode); | |
75 | } | |
76 | ||
77 | static 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 | ||
1ae9bd8b AV |
84 | static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode) |
85 | { | |
86 | struct files_struct *files = get_files_struct(task); | |
87 | struct file *file; | |
88 | ||
89 | if (!files) | |
90 | return false; | |
91 | ||
92 | rcu_read_lock(); | |
93 | file = fcheck_files(files, fd); | |
94 | if (file) | |
95 | *mode = file->f_mode; | |
96 | rcu_read_unlock(); | |
97 | put_files_struct(files); | |
98 | return !!file; | |
99 | } | |
100 | ||
98836386 AV |
101 | static void tid_fd_update_inode(struct task_struct *task, struct inode *inode, |
102 | fmode_t f_mode) | |
103 | { | |
104 | task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); | |
105 | ||
106 | if (S_ISLNK(inode->i_mode)) { | |
107 | unsigned i_mode = S_IFLNK; | |
108 | if (f_mode & FMODE_READ) | |
109 | i_mode |= S_IRUSR | S_IXUSR; | |
110 | if (f_mode & FMODE_WRITE) | |
111 | i_mode |= S_IWUSR | S_IXUSR; | |
112 | inode->i_mode = i_mode; | |
113 | } | |
114 | security_task_to_inode(task, inode); | |
115 | } | |
116 | ||
faf60af1 CG |
117 | static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) |
118 | { | |
faf60af1 | 119 | struct task_struct *task; |
faf60af1 | 120 | struct inode *inode; |
771187d6 | 121 | unsigned int fd; |
faf60af1 CG |
122 | |
123 | if (flags & LOOKUP_RCU) | |
124 | return -ECHILD; | |
125 | ||
2b0143b5 | 126 | inode = d_inode(dentry); |
faf60af1 CG |
127 | task = get_proc_task(inode); |
128 | fd = proc_fd(inode); | |
129 | ||
130 | if (task) { | |
98836386 | 131 | fmode_t f_mode; |
1ae9bd8b | 132 | if (tid_fd_mode(task, fd, &f_mode)) { |
98836386 | 133 | tid_fd_update_inode(task, inode, f_mode); |
1ae9bd8b AV |
134 | put_task_struct(task); |
135 | return 1; | |
faf60af1 CG |
136 | } |
137 | put_task_struct(task); | |
138 | } | |
faf60af1 CG |
139 | return 0; |
140 | } | |
141 | ||
142 | static const struct dentry_operations tid_fd_dentry_operations = { | |
143 | .d_revalidate = tid_fd_revalidate, | |
144 | .d_delete = pid_delete_dentry, | |
145 | }; | |
146 | ||
147 | static int proc_fd_link(struct dentry *dentry, struct path *path) | |
148 | { | |
ddd3e077 CG |
149 | struct files_struct *files = NULL; |
150 | struct task_struct *task; | |
151 | int ret = -ENOENT; | |
152 | ||
2b0143b5 | 153 | task = get_proc_task(d_inode(dentry)); |
ddd3e077 CG |
154 | if (task) { |
155 | files = get_files_struct(task); | |
156 | put_task_struct(task); | |
157 | } | |
158 | ||
159 | if (files) { | |
771187d6 | 160 | unsigned int fd = proc_fd(d_inode(dentry)); |
ddd3e077 CG |
161 | struct file *fd_file; |
162 | ||
163 | spin_lock(&files->file_lock); | |
164 | fd_file = fcheck_files(files, fd); | |
165 | if (fd_file) { | |
166 | *path = fd_file->f_path; | |
167 | path_get(&fd_file->f_path); | |
168 | ret = 0; | |
169 | } | |
170 | spin_unlock(&files->file_lock); | |
171 | put_files_struct(files); | |
172 | } | |
173 | ||
174 | return ret; | |
faf60af1 CG |
175 | } |
176 | ||
98836386 AV |
177 | struct fd_data { |
178 | fmode_t mode; | |
179 | unsigned fd; | |
180 | }; | |
181 | ||
0168b9e3 AV |
182 | static struct dentry *proc_fd_instantiate(struct dentry *dentry, |
183 | struct task_struct *task, const void *ptr) | |
faf60af1 | 184 | { |
98836386 | 185 | const struct fd_data *data = ptr; |
faf60af1 CG |
186 | struct proc_inode *ei; |
187 | struct inode *inode; | |
188 | ||
0168b9e3 | 189 | inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK); |
faf60af1 | 190 | if (!inode) |
0168b9e3 | 191 | return ERR_PTR(-ENOENT); |
faf60af1 CG |
192 | |
193 | ei = PROC_I(inode); | |
98836386 | 194 | ei->fd = data->fd; |
faf60af1 | 195 | |
faf60af1 CG |
196 | inode->i_op = &proc_pid_link_inode_operations; |
197 | inode->i_size = 64; | |
198 | ||
199 | ei->op.proc_get_link = proc_fd_link; | |
98836386 | 200 | tid_fd_update_inode(task, inode, data->mode); |
faf60af1 CG |
201 | |
202 | d_set_d_op(dentry, &tid_fd_dentry_operations); | |
0168b9e3 | 203 | return d_splice_alias(inode, dentry); |
faf60af1 CG |
204 | } |
205 | ||
206 | static struct dentry *proc_lookupfd_common(struct inode *dir, | |
207 | struct dentry *dentry, | |
208 | instantiate_t instantiate) | |
209 | { | |
210 | struct task_struct *task = get_proc_task(dir); | |
98836386 | 211 | struct fd_data data = {.fd = name_to_int(&dentry->d_name)}; |
0168b9e3 | 212 | struct dentry *result = ERR_PTR(-ENOENT); |
faf60af1 CG |
213 | |
214 | if (!task) | |
215 | goto out_no_task; | |
98836386 | 216 | if (data.fd == ~0U) |
faf60af1 | 217 | goto out; |
98836386 | 218 | if (!tid_fd_mode(task, data.fd, &data.mode)) |
1ae9bd8b | 219 | goto out; |
faf60af1 | 220 | |
0168b9e3 | 221 | result = instantiate(dentry, task, &data); |
faf60af1 CG |
222 | out: |
223 | put_task_struct(task); | |
224 | out_no_task: | |
0168b9e3 | 225 | return result; |
faf60af1 CG |
226 | } |
227 | ||
f0c3b509 AV |
228 | static int proc_readfd_common(struct file *file, struct dir_context *ctx, |
229 | instantiate_t instantiate) | |
faf60af1 | 230 | { |
f0c3b509 | 231 | struct task_struct *p = get_proc_task(file_inode(file)); |
faf60af1 | 232 | struct files_struct *files; |
f0c3b509 | 233 | unsigned int fd; |
faf60af1 | 234 | |
faf60af1 | 235 | if (!p) |
f0c3b509 | 236 | return -ENOENT; |
faf60af1 | 237 | |
f0c3b509 AV |
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++) { | |
98836386 AV |
248 | struct file *f; |
249 | struct fd_data data; | |
e3912ac3 | 250 | char name[10 + 1]; |
a4ef3895 | 251 | unsigned int len; |
f0c3b509 | 252 | |
98836386 AV |
253 | f = fcheck_files(files, fd); |
254 | if (!f) | |
f0c3b509 | 255 | continue; |
98836386 | 256 | data.mode = f->f_mode; |
f0c3b509 | 257 | rcu_read_unlock(); |
98836386 | 258 | data.fd = fd; |
f0c3b509 | 259 | |
771187d6 | 260 | len = snprintf(name, sizeof(name), "%u", fd); |
f0c3b509 AV |
261 | if (!proc_fill_cache(file, ctx, |
262 | name, len, instantiate, p, | |
98836386 | 263 | &data)) |
f0c3b509 | 264 | goto out_fd_loop; |
3cc4a84e | 265 | cond_resched(); |
f0c3b509 | 266 | rcu_read_lock(); |
faf60af1 | 267 | } |
f0c3b509 AV |
268 | rcu_read_unlock(); |
269 | out_fd_loop: | |
270 | put_files_struct(files); | |
faf60af1 CG |
271 | out: |
272 | put_task_struct(p); | |
f0c3b509 | 273 | return 0; |
faf60af1 CG |
274 | } |
275 | ||
f0c3b509 | 276 | static int proc_readfd(struct file *file, struct dir_context *ctx) |
faf60af1 | 277 | { |
f0c3b509 | 278 | return proc_readfd_common(file, ctx, proc_fd_instantiate); |
faf60af1 CG |
279 | } |
280 | ||
281 | const struct file_operations proc_fd_operations = { | |
282 | .read = generic_read_dir, | |
f50752ea AV |
283 | .iterate_shared = proc_readfd, |
284 | .llseek = generic_file_llseek, | |
faf60af1 CG |
285 | }; |
286 | ||
287 | static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry, | |
288 | unsigned int flags) | |
289 | { | |
290 | return proc_lookupfd_common(dir, dentry, proc_fd_instantiate); | |
291 | } | |
292 | ||
293 | /* | |
294 | * /proc/pid/fd needs a special permission handler so that a process can still | |
295 | * access /proc/self/fd after it has executed a setuid(). | |
296 | */ | |
297 | int proc_fd_permission(struct inode *inode, int mask) | |
298 | { | |
54708d28 ON |
299 | struct task_struct *p; |
300 | int rv; | |
301 | ||
302 | rv = generic_permission(inode, mask); | |
faf60af1 | 303 | if (rv == 0) |
54708d28 ON |
304 | return rv; |
305 | ||
306 | rcu_read_lock(); | |
307 | p = pid_task(proc_pid(inode), PIDTYPE_PID); | |
308 | if (p && same_thread_group(p, current)) | |
faf60af1 | 309 | rv = 0; |
54708d28 ON |
310 | rcu_read_unlock(); |
311 | ||
faf60af1 CG |
312 | return rv; |
313 | } | |
314 | ||
315 | const struct inode_operations proc_fd_inode_operations = { | |
316 | .lookup = proc_lookupfd, | |
317 | .permission = proc_fd_permission, | |
318 | .setattr = proc_setattr, | |
319 | }; | |
320 | ||
0168b9e3 AV |
321 | static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, |
322 | struct task_struct *task, const void *ptr) | |
faf60af1 | 323 | { |
98836386 | 324 | const struct fd_data *data = ptr; |
faf60af1 CG |
325 | struct proc_inode *ei; |
326 | struct inode *inode; | |
327 | ||
0168b9e3 | 328 | inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUSR); |
faf60af1 | 329 | if (!inode) |
0168b9e3 | 330 | return ERR_PTR(-ENOENT); |
faf60af1 CG |
331 | |
332 | ei = PROC_I(inode); | |
98836386 | 333 | ei->fd = data->fd; |
faf60af1 | 334 | |
faf60af1 | 335 | inode->i_fop = &proc_fdinfo_file_operations; |
98836386 | 336 | tid_fd_update_inode(task, inode, 0); |
faf60af1 CG |
337 | |
338 | d_set_d_op(dentry, &tid_fd_dentry_operations); | |
0168b9e3 | 339 | return d_splice_alias(inode, dentry); |
faf60af1 CG |
340 | } |
341 | ||
342 | static struct dentry * | |
343 | proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
344 | { | |
345 | return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate); | |
346 | } | |
347 | ||
f0c3b509 | 348 | static int proc_readfdinfo(struct file *file, struct dir_context *ctx) |
faf60af1 | 349 | { |
f0c3b509 | 350 | return proc_readfd_common(file, ctx, |
faf60af1 CG |
351 | proc_fdinfo_instantiate); |
352 | } | |
353 | ||
354 | const struct inode_operations proc_fdinfo_inode_operations = { | |
355 | .lookup = proc_lookupfdinfo, | |
356 | .setattr = proc_setattr, | |
357 | }; | |
358 | ||
359 | const struct file_operations proc_fdinfo_operations = { | |
360 | .read = generic_read_dir, | |
f50752ea AV |
361 | .iterate_shared = proc_readfdinfo, |
362 | .llseek = generic_file_llseek, | |
faf60af1 | 363 | }; |