| | 1 | // SPDX-License-Identifier: GPL-2.0 |
| | 2 | /* |
| | 3 | * linux/fs/fcntl.c |
| | 4 | * |
| | 5 | * Copyright (C) 1991, 1992 Linus Torvalds |
| | 6 | */ |
| | 7 | |
| | 8 | #include <linux/syscalls.h> |
| | 9 | #include <linux/init.h> |
| | 10 | #include <linux/mm.h> |
| | 11 | #include <linux/sched/task.h> |
| | 12 | #include <linux/fs.h> |
| | 13 | #include <linux/file.h> |
| | 14 | #include <linux/fdtable.h> |
| | 15 | #include <linux/capability.h> |
| | 16 | #include <linux/dnotify.h> |
| | 17 | #include <linux/slab.h> |
| | 18 | #include <linux/module.h> |
| | 19 | #include <linux/pipe_fs_i.h> |
| | 20 | #include <linux/security.h> |
| | 21 | #include <linux/ptrace.h> |
| | 22 | #include <linux/signal.h> |
| | 23 | #include <linux/rcupdate.h> |
| | 24 | #include <linux/pid_namespace.h> |
| | 25 | #include <linux/user_namespace.h> |
| | 26 | #include <linux/memfd.h> |
| | 27 | #include <linux/compat.h> |
| | 28 | |
| | 29 | #include <linux/poll.h> |
| | 30 | #include <asm/siginfo.h> |
| | 31 | #include <linux/uaccess.h> |
| | 32 | |
| | 33 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
| | 34 | |
| | 35 | int setfl(int fd, struct file *filp, unsigned long arg) |
| | 36 | { |
| | 37 | struct inode * inode = file_inode(filp); |
| | 38 | int error = 0; |
| | 39 | |
| | 40 | /* |
| | 41 | * O_APPEND cannot be cleared if the file is marked as append-only |
| | 42 | * and the file is open for write. |
| | 43 | */ |
| | 44 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) |
| | 45 | return -EPERM; |
| | 46 | |
| | 47 | /* O_NOATIME can only be set by the owner or superuser */ |
| | 48 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) |
| | 49 | if (!inode_owner_or_capable(inode)) |
| | 50 | return -EPERM; |
| | 51 | |
| | 52 | /* required for strict SunOS emulation */ |
| | 53 | if (O_NONBLOCK != O_NDELAY) |
| | 54 | if (arg & O_NDELAY) |
| | 55 | arg |= O_NONBLOCK; |
| | 56 | |
| | 57 | /* Pipe packetized mode is controlled by O_DIRECT flag */ |
| | 58 | if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) { |
| | 59 | if (!filp->f_mapping || !filp->f_mapping->a_ops || |
| | 60 | !filp->f_mapping->a_ops->direct_IO) |
| | 61 | return -EINVAL; |
| | 62 | } |
| | 63 | |
| | 64 | if (filp->f_op->check_flags) |
| | 65 | error = filp->f_op->check_flags(arg); |
| | 66 | if (!error && filp->f_op->setfl) |
| | 67 | error = filp->f_op->setfl(filp, arg); |
| | 68 | if (error) |
| | 69 | return error; |
| | 70 | |
| | 71 | /* |
| | 72 | * ->fasync() is responsible for setting the FASYNC bit. |
| | 73 | */ |
| | 74 | if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { |
| | 75 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
| | 76 | if (error < 0) |
| | 77 | goto out; |
| | 78 | if (error > 0) |
| | 79 | error = 0; |
| | 80 | } |
| | 81 | spin_lock(&filp->f_lock); |
| | 82 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
| | 83 | spin_unlock(&filp->f_lock); |
| | 84 | |
| | 85 | out: |
| | 86 | return error; |
| | 87 | } |
| | 88 | EXPORT_SYMBOL_GPL(setfl); |
| | 89 | |
| | 90 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
| | 91 | int force) |
| | 92 | { |
| | 93 | write_lock_irq(&filp->f_owner.lock); |
| | 94 | if (force || !filp->f_owner.pid) { |
| | 95 | put_pid(filp->f_owner.pid); |
| | 96 | filp->f_owner.pid = get_pid(pid); |
| | 97 | filp->f_owner.pid_type = type; |
| | 98 | |
| | 99 | if (pid) { |
| | 100 | const struct cred *cred = current_cred(); |
| | 101 | filp->f_owner.uid = cred->uid; |
| | 102 | filp->f_owner.euid = cred->euid; |
| | 103 | } |
| | 104 | } |
| | 105 | write_unlock_irq(&filp->f_owner.lock); |
| | 106 | } |
| | 107 | |
| | 108 | void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
| | 109 | int force) |
| | 110 | { |
| | 111 | security_file_set_fowner(filp); |
| | 112 | f_modown(filp, pid, type, force); |
| | 113 | } |
| | 114 | EXPORT_SYMBOL(__f_setown); |
| | 115 | |
| | 116 | int f_setown(struct file *filp, unsigned long arg, int force) |
| | 117 | { |
| | 118 | enum pid_type type; |
| | 119 | struct pid *pid = NULL; |
| | 120 | int who = arg, ret = 0; |
| | 121 | |
| | 122 | type = PIDTYPE_TGID; |
| | 123 | if (who < 0) { |
| | 124 | /* avoid overflow below */ |
| | 125 | if (who == INT_MIN) |
| | 126 | return -EINVAL; |
| | 127 | |
| | 128 | type = PIDTYPE_PGID; |
| | 129 | who = -who; |
| | 130 | } |
| | 131 | |
| | 132 | rcu_read_lock(); |
| | 133 | if (who) { |
| | 134 | pid = find_vpid(who); |
| | 135 | if (!pid) |
| | 136 | ret = -ESRCH; |
| | 137 | } |
| | 138 | |
| | 139 | if (!ret) |
| | 140 | __f_setown(filp, pid, type, force); |
| | 141 | rcu_read_unlock(); |
| | 142 | |
| | 143 | return ret; |
| | 144 | } |
| | 145 | EXPORT_SYMBOL(f_setown); |
| | 146 | |
| | 147 | void f_delown(struct file *filp) |
| | 148 | { |
| | 149 | f_modown(filp, NULL, PIDTYPE_TGID, 1); |
| | 150 | } |
| | 151 | |
| | 152 | pid_t f_getown(struct file *filp) |
| | 153 | { |
| | 154 | pid_t pid; |
| | 155 | read_lock(&filp->f_owner.lock); |
| | 156 | pid = pid_vnr(filp->f_owner.pid); |
| | 157 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
| | 158 | pid = -pid; |
| | 159 | read_unlock(&filp->f_owner.lock); |
| | 160 | return pid; |
| | 161 | } |
| | 162 | |
| | 163 | static int f_setown_ex(struct file *filp, unsigned long arg) |
| | 164 | { |
| | 165 | struct f_owner_ex __user *owner_p = (void __user *)arg; |
| | 166 | struct f_owner_ex owner; |
| | 167 | struct pid *pid; |
| | 168 | int type; |
| | 169 | int ret; |
| | 170 | |
| | 171 | ret = copy_from_user(&owner, owner_p, sizeof(owner)); |
| | 172 | if (ret) |
| | 173 | return -EFAULT; |
| | 174 | |
| | 175 | switch (owner.type) { |
| | 176 | case F_OWNER_TID: |
| | 177 | type = PIDTYPE_PID; |
| | 178 | break; |
| | 179 | |
| | 180 | case F_OWNER_PID: |
| | 181 | type = PIDTYPE_TGID; |
| | 182 | break; |
| | 183 | |
| | 184 | case F_OWNER_PGRP: |
| | 185 | type = PIDTYPE_PGID; |
| | 186 | break; |
| | 187 | |
| | 188 | default: |
| | 189 | return -EINVAL; |
| | 190 | } |
| | 191 | |
| | 192 | rcu_read_lock(); |
| | 193 | pid = find_vpid(owner.pid); |
| | 194 | if (owner.pid && !pid) |
| | 195 | ret = -ESRCH; |
| | 196 | else |
| | 197 | __f_setown(filp, pid, type, 1); |
| | 198 | rcu_read_unlock(); |
| | 199 | |
| | 200 | return ret; |
| | 201 | } |
| | 202 | |
| | 203 | static int f_getown_ex(struct file *filp, unsigned long arg) |
| | 204 | { |
| | 205 | struct f_owner_ex __user *owner_p = (void __user *)arg; |
| | 206 | struct f_owner_ex owner; |
| | 207 | int ret = 0; |
| | 208 | |
| | 209 | read_lock(&filp->f_owner.lock); |
| | 210 | owner.pid = pid_vnr(filp->f_owner.pid); |
| | 211 | switch (filp->f_owner.pid_type) { |
| | 212 | case PIDTYPE_PID: |
| | 213 | owner.type = F_OWNER_TID; |
| | 214 | break; |
| | 215 | |
| | 216 | case PIDTYPE_TGID: |
| | 217 | owner.type = F_OWNER_PID; |
| | 218 | break; |
| | 219 | |
| | 220 | case PIDTYPE_PGID: |
| | 221 | owner.type = F_OWNER_PGRP; |
| | 222 | break; |
| | 223 | |
| | 224 | default: |
| | 225 | WARN_ON(1); |
| | 226 | ret = -EINVAL; |
| | 227 | break; |
| | 228 | } |
| | 229 | read_unlock(&filp->f_owner.lock); |
| | 230 | |
| | 231 | if (!ret) { |
| | 232 | ret = copy_to_user(owner_p, &owner, sizeof(owner)); |
| | 233 | if (ret) |
| | 234 | ret = -EFAULT; |
| | 235 | } |
| | 236 | return ret; |
| | 237 | } |
| | 238 | |
| | 239 | #ifdef CONFIG_CHECKPOINT_RESTORE |
| | 240 | static int f_getowner_uids(struct file *filp, unsigned long arg) |
| | 241 | { |
| | 242 | struct user_namespace *user_ns = current_user_ns(); |
| | 243 | uid_t __user *dst = (void __user *)arg; |
| | 244 | uid_t src[2]; |
| | 245 | int err; |
| | 246 | |
| | 247 | read_lock(&filp->f_owner.lock); |
| | 248 | src[0] = from_kuid(user_ns, filp->f_owner.uid); |
| | 249 | src[1] = from_kuid(user_ns, filp->f_owner.euid); |
| | 250 | read_unlock(&filp->f_owner.lock); |
| | 251 | |
| | 252 | err = put_user(src[0], &dst[0]); |
| | 253 | err |= put_user(src[1], &dst[1]); |
| | 254 | |
| | 255 | return err; |
| | 256 | } |
| | 257 | #else |
| | 258 | static int f_getowner_uids(struct file *filp, unsigned long arg) |
| | 259 | { |
| | 260 | return -EINVAL; |
| | 261 | } |
| | 262 | #endif |
| | 263 | |
| | 264 | static bool rw_hint_valid(enum rw_hint hint) |
| | 265 | { |
| | 266 | switch (hint) { |
| | 267 | case RWF_WRITE_LIFE_NOT_SET: |
| | 268 | case RWH_WRITE_LIFE_NONE: |
| | 269 | case RWH_WRITE_LIFE_SHORT: |
| | 270 | case RWH_WRITE_LIFE_MEDIUM: |
| | 271 | case RWH_WRITE_LIFE_LONG: |
| | 272 | case RWH_WRITE_LIFE_EXTREME: |
| | 273 | return true; |
| | 274 | default: |
| | 275 | return false; |
| | 276 | } |
| | 277 | } |
| | 278 | |
| | 279 | static long fcntl_rw_hint(struct file *file, unsigned int cmd, |
| | 280 | unsigned long arg) |
| | 281 | { |
| | 282 | struct inode *inode = file_inode(file); |
| | 283 | u64 *argp = (u64 __user *)arg; |
| | 284 | enum rw_hint hint; |
| | 285 | u64 h; |
| | 286 | |
| | 287 | switch (cmd) { |
| | 288 | case F_GET_FILE_RW_HINT: |
| | 289 | h = file_write_hint(file); |
| | 290 | if (copy_to_user(argp, &h, sizeof(*argp))) |
| | 291 | return -EFAULT; |
| | 292 | return 0; |
| | 293 | case F_SET_FILE_RW_HINT: |
| | 294 | if (copy_from_user(&h, argp, sizeof(h))) |
| | 295 | return -EFAULT; |
| | 296 | hint = (enum rw_hint) h; |
| | 297 | if (!rw_hint_valid(hint)) |
| | 298 | return -EINVAL; |
| | 299 | |
| | 300 | spin_lock(&file->f_lock); |
| | 301 | file->f_write_hint = hint; |
| | 302 | spin_unlock(&file->f_lock); |
| | 303 | return 0; |
| | 304 | case F_GET_RW_HINT: |
| | 305 | h = inode->i_write_hint; |
| | 306 | if (copy_to_user(argp, &h, sizeof(*argp))) |
| | 307 | return -EFAULT; |
| | 308 | return 0; |
| | 309 | case F_SET_RW_HINT: |
| | 310 | if (copy_from_user(&h, argp, sizeof(h))) |
| | 311 | return -EFAULT; |
| | 312 | hint = (enum rw_hint) h; |
| | 313 | if (!rw_hint_valid(hint)) |
| | 314 | return -EINVAL; |
| | 315 | |
| | 316 | inode_lock(inode); |
| | 317 | inode->i_write_hint = hint; |
| | 318 | inode_unlock(inode); |
| | 319 | return 0; |
| | 320 | default: |
| | 321 | return -EINVAL; |
| | 322 | } |
| | 323 | } |
| | 324 | |
| | 325 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, |
| | 326 | struct file *filp) |
| | 327 | { |
| | 328 | void __user *argp = (void __user *)arg; |
| | 329 | struct flock flock; |
| | 330 | long err = -EINVAL; |
| | 331 | |
| | 332 | switch (cmd) { |
| | 333 | case F_DUPFD: |
| | 334 | err = f_dupfd(arg, filp, 0); |
| | 335 | break; |
| | 336 | case F_DUPFD_CLOEXEC: |
| | 337 | err = f_dupfd(arg, filp, O_CLOEXEC); |
| | 338 | break; |
| | 339 | case F_GETFD: |
| | 340 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; |
| | 341 | break; |
| | 342 | case F_SETFD: |
| | 343 | err = 0; |
| | 344 | set_close_on_exec(fd, arg & FD_CLOEXEC); |
| | 345 | break; |
| | 346 | case F_GETFL: |
| | 347 | err = filp->f_flags; |
| | 348 | break; |
| | 349 | case F_SETFL: |
| | 350 | err = setfl(fd, filp, arg); |
| | 351 | break; |
| | 352 | #if BITS_PER_LONG != 32 |
| | 353 | /* 32-bit arches must use fcntl64() */ |
| | 354 | case F_OFD_GETLK: |
| | 355 | #endif |
| | 356 | case F_GETLK: |
| | 357 | if (copy_from_user(&flock, argp, sizeof(flock))) |
| | 358 | return -EFAULT; |
| | 359 | err = fcntl_getlk(filp, cmd, &flock); |
| | 360 | if (!err && copy_to_user(argp, &flock, sizeof(flock))) |
| | 361 | return -EFAULT; |
| | 362 | break; |
| | 363 | #if BITS_PER_LONG != 32 |
| | 364 | /* 32-bit arches must use fcntl64() */ |
| | 365 | case F_OFD_SETLK: |
| | 366 | case F_OFD_SETLKW: |
| | 367 | #endif |
| | 368 | /* Fallthrough */ |
| | 369 | case F_SETLK: |
| | 370 | case F_SETLKW: |
| | 371 | if (copy_from_user(&flock, argp, sizeof(flock))) |
| | 372 | return -EFAULT; |
| | 373 | err = fcntl_setlk(fd, filp, cmd, &flock); |
| | 374 | break; |
| | 375 | case F_GETOWN: |
| | 376 | /* |
| | 377 | * XXX If f_owner is a process group, the |
| | 378 | * negative return value will get converted |
| | 379 | * into an error. Oops. If we keep the |
| | 380 | * current syscall conventions, the only way |
| | 381 | * to fix this will be in libc. |
| | 382 | */ |
| | 383 | err = f_getown(filp); |
| | 384 | force_successful_syscall_return(); |
| | 385 | break; |
| | 386 | case F_SETOWN: |
| | 387 | err = f_setown(filp, arg, 1); |
| | 388 | break; |
| | 389 | case F_GETOWN_EX: |
| | 390 | err = f_getown_ex(filp, arg); |
| | 391 | break; |
| | 392 | case F_SETOWN_EX: |
| | 393 | err = f_setown_ex(filp, arg); |
| | 394 | break; |
| | 395 | case F_GETOWNER_UIDS: |
| | 396 | err = f_getowner_uids(filp, arg); |
| | 397 | break; |
| | 398 | case F_GETSIG: |
| | 399 | err = filp->f_owner.signum; |
| | 400 | break; |
| | 401 | case F_SETSIG: |
| | 402 | /* arg == 0 restores default behaviour. */ |
| | 403 | if (!valid_signal(arg)) { |
| | 404 | break; |
| | 405 | } |
| | 406 | err = 0; |
| | 407 | filp->f_owner.signum = arg; |
| | 408 | break; |
| | 409 | case F_GETLEASE: |
| | 410 | err = fcntl_getlease(filp); |
| | 411 | break; |
| | 412 | case F_SETLEASE: |
| | 413 | err = fcntl_setlease(fd, filp, arg); |
| | 414 | break; |
| | 415 | case F_NOTIFY: |
| | 416 | err = fcntl_dirnotify(fd, filp, arg); |
| | 417 | break; |
| | 418 | case F_SETPIPE_SZ: |
| | 419 | case F_GETPIPE_SZ: |
| | 420 | err = pipe_fcntl(filp, cmd, arg); |
| | 421 | break; |
| | 422 | case F_ADD_SEALS: |
| | 423 | case F_GET_SEALS: |
| | 424 | err = memfd_fcntl(filp, cmd, arg); |
| | 425 | break; |
| | 426 | case F_GET_RW_HINT: |
| | 427 | case F_SET_RW_HINT: |
| | 428 | case F_GET_FILE_RW_HINT: |
| | 429 | case F_SET_FILE_RW_HINT: |
| | 430 | err = fcntl_rw_hint(filp, cmd, arg); |
| | 431 | break; |
| | 432 | default: |
| | 433 | break; |
| | 434 | } |
| | 435 | return err; |
| | 436 | } |
| | 437 | |
| | 438 | static int check_fcntl_cmd(unsigned cmd) |
| | 439 | { |
| | 440 | switch (cmd) { |
| | 441 | case F_DUPFD: |
| | 442 | case F_DUPFD_CLOEXEC: |
| | 443 | case F_GETFD: |
| | 444 | case F_SETFD: |
| | 445 | case F_GETFL: |
| | 446 | return 1; |
| | 447 | } |
| | 448 | return 0; |
| | 449 | } |
| | 450 | |
| | 451 | SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
| | 452 | { |
| | 453 | struct fd f = fdget_raw(fd); |
| | 454 | long err = -EBADF; |
| | 455 | |
| | 456 | if (!f.file) |
| | 457 | goto out; |
| | 458 | |
| | 459 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
| | 460 | if (!check_fcntl_cmd(cmd)) |
| | 461 | goto out1; |
| | 462 | } |
| | 463 | |
| | 464 | err = security_file_fcntl(f.file, cmd, arg); |
| | 465 | if (!err) |
| | 466 | err = do_fcntl(fd, cmd, arg, f.file); |
| | 467 | |
| | 468 | out1: |
| | 469 | fdput(f); |
| | 470 | out: |
| | 471 | return err; |
| | 472 | } |
| | 473 | |
| | 474 | #if BITS_PER_LONG == 32 |
| | 475 | SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
| | 476 | unsigned long, arg) |
| | 477 | { |
| | 478 | void __user *argp = (void __user *)arg; |
| | 479 | struct fd f = fdget_raw(fd); |
| | 480 | struct flock64 flock; |
| | 481 | long err = -EBADF; |
| | 482 | |
| | 483 | if (!f.file) |
| | 484 | goto out; |
| | 485 | |
| | 486 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
| | 487 | if (!check_fcntl_cmd(cmd)) |
| | 488 | goto out1; |
| | 489 | } |
| | 490 | |
| | 491 | err = security_file_fcntl(f.file, cmd, arg); |
| | 492 | if (err) |
| | 493 | goto out1; |
| | 494 | |
| | 495 | switch (cmd) { |
| | 496 | case F_GETLK64: |
| | 497 | case F_OFD_GETLK: |
| | 498 | err = -EFAULT; |
| | 499 | if (copy_from_user(&flock, argp, sizeof(flock))) |
| | 500 | break; |
| | 501 | err = fcntl_getlk64(f.file, cmd, &flock); |
| | 502 | if (!err && copy_to_user(argp, &flock, sizeof(flock))) |
| | 503 | err = -EFAULT; |
| | 504 | break; |
| | 505 | case F_SETLK64: |
| | 506 | case F_SETLKW64: |
| | 507 | case F_OFD_SETLK: |
| | 508 | case F_OFD_SETLKW: |
| | 509 | err = -EFAULT; |
| | 510 | if (copy_from_user(&flock, argp, sizeof(flock))) |
| | 511 | break; |
| | 512 | err = fcntl_setlk64(fd, f.file, cmd, &flock); |
| | 513 | break; |
| | 514 | default: |
| | 515 | err = do_fcntl(fd, cmd, arg, f.file); |
| | 516 | break; |
| | 517 | } |
| | 518 | out1: |
| | 519 | fdput(f); |
| | 520 | out: |
| | 521 | return err; |
| | 522 | } |
| | 523 | #endif |
| | 524 | |
| | 525 | #ifdef CONFIG_COMPAT |
| | 526 | /* careful - don't use anywhere else */ |
| | 527 | #define copy_flock_fields(dst, src) \ |
| | 528 | (dst)->l_type = (src)->l_type; \ |
| | 529 | (dst)->l_whence = (src)->l_whence; \ |
| | 530 | (dst)->l_start = (src)->l_start; \ |
| | 531 | (dst)->l_len = (src)->l_len; \ |
| | 532 | (dst)->l_pid = (src)->l_pid; |
| | 533 | |
| | 534 | static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl) |
| | 535 | { |
| | 536 | struct compat_flock fl; |
| | 537 | |
| | 538 | if (copy_from_user(&fl, ufl, sizeof(struct compat_flock))) |
| | 539 | return -EFAULT; |
| | 540 | copy_flock_fields(kfl, &fl); |
| | 541 | return 0; |
| | 542 | } |
| | 543 | |
| | 544 | static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl) |
| | 545 | { |
| | 546 | struct compat_flock64 fl; |
| | 547 | |
| | 548 | if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64))) |
| | 549 | return -EFAULT; |
| | 550 | copy_flock_fields(kfl, &fl); |
| | 551 | return 0; |
| | 552 | } |
| | 553 | |
| | 554 | static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl) |
| | 555 | { |
| | 556 | struct compat_flock fl; |
| | 557 | |
| | 558 | memset(&fl, 0, sizeof(struct compat_flock)); |
| | 559 | copy_flock_fields(&fl, kfl); |
| | 560 | if (copy_to_user(ufl, &fl, sizeof(struct compat_flock))) |
| | 561 | return -EFAULT; |
| | 562 | return 0; |
| | 563 | } |
| | 564 | |
| | 565 | static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl) |
| | 566 | { |
| | 567 | struct compat_flock64 fl; |
| | 568 | |
| | 569 | BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start)); |
| | 570 | BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len)); |
| | 571 | |
| | 572 | memset(&fl, 0, sizeof(struct compat_flock64)); |
| | 573 | copy_flock_fields(&fl, kfl); |
| | 574 | if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64))) |
| | 575 | return -EFAULT; |
| | 576 | return 0; |
| | 577 | } |
| | 578 | #undef copy_flock_fields |
| | 579 | |
| | 580 | static unsigned int |
| | 581 | convert_fcntl_cmd(unsigned int cmd) |
| | 582 | { |
| | 583 | switch (cmd) { |
| | 584 | case F_GETLK64: |
| | 585 | return F_GETLK; |
| | 586 | case F_SETLK64: |
| | 587 | return F_SETLK; |
| | 588 | case F_SETLKW64: |
| | 589 | return F_SETLKW; |
| | 590 | } |
| | 591 | |
| | 592 | return cmd; |
| | 593 | } |
| | 594 | |
| | 595 | /* |
| | 596 | * GETLK was successful and we need to return the data, but it needs to fit in |
| | 597 | * the compat structure. |
| | 598 | * l_start shouldn't be too big, unless the original start + end is greater than |
| | 599 | * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return |
| | 600 | * -EOVERFLOW in that case. l_len could be too big, in which case we just |
| | 601 | * truncate it, and only allow the app to see that part of the conflicting lock |
| | 602 | * that might make sense to it anyway |
| | 603 | */ |
| | 604 | static int fixup_compat_flock(struct flock *flock) |
| | 605 | { |
| | 606 | if (flock->l_start > COMPAT_OFF_T_MAX) |
| | 607 | return -EOVERFLOW; |
| | 608 | if (flock->l_len > COMPAT_OFF_T_MAX) |
| | 609 | flock->l_len = COMPAT_OFF_T_MAX; |
| | 610 | return 0; |
| | 611 | } |
| | 612 | |
| | 613 | static long do_compat_fcntl64(unsigned int fd, unsigned int cmd, |
| | 614 | compat_ulong_t arg) |
| | 615 | { |
| | 616 | struct fd f = fdget_raw(fd); |
| | 617 | struct flock flock; |
| | 618 | long err = -EBADF; |
| | 619 | |
| | 620 | if (!f.file) |
| | 621 | return err; |
| | 622 | |
| | 623 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
| | 624 | if (!check_fcntl_cmd(cmd)) |
| | 625 | goto out_put; |
| | 626 | } |
| | 627 | |
| | 628 | err = security_file_fcntl(f.file, cmd, arg); |
| | 629 | if (err) |
| | 630 | goto out_put; |
| | 631 | |
| | 632 | switch (cmd) { |
| | 633 | case F_GETLK: |
| | 634 | err = get_compat_flock(&flock, compat_ptr(arg)); |
| | 635 | if (err) |
| | 636 | break; |
| | 637 | err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); |
| | 638 | if (err) |
| | 639 | break; |
| | 640 | err = fixup_compat_flock(&flock); |
| | 641 | if (!err) |
| | 642 | err = put_compat_flock(&flock, compat_ptr(arg)); |
| | 643 | break; |
| | 644 | case F_GETLK64: |
| | 645 | case F_OFD_GETLK: |
| | 646 | err = get_compat_flock64(&flock, compat_ptr(arg)); |
| | 647 | if (err) |
| | 648 | break; |
| | 649 | err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); |
| | 650 | if (!err) |
| | 651 | err = put_compat_flock64(&flock, compat_ptr(arg)); |
| | 652 | break; |
| | 653 | case F_SETLK: |
| | 654 | case F_SETLKW: |
| | 655 | err = get_compat_flock(&flock, compat_ptr(arg)); |
| | 656 | if (err) |
| | 657 | break; |
| | 658 | err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); |
| | 659 | break; |
| | 660 | case F_SETLK64: |
| | 661 | case F_SETLKW64: |
| | 662 | case F_OFD_SETLK: |
| | 663 | case F_OFD_SETLKW: |
| | 664 | err = get_compat_flock64(&flock, compat_ptr(arg)); |
| | 665 | if (err) |
| | 666 | break; |
| | 667 | err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock); |
| | 668 | break; |
| | 669 | default: |
| | 670 | err = do_fcntl(fd, cmd, arg, f.file); |
| | 671 | break; |
| | 672 | } |
| | 673 | out_put: |
| | 674 | fdput(f); |
| | 675 | return err; |
| | 676 | } |
| | 677 | |
| | 678 | COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
| | 679 | compat_ulong_t, arg) |
| | 680 | { |
| | 681 | return do_compat_fcntl64(fd, cmd, arg); |
| | 682 | } |
| | 683 | |
| | 684 | COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, |
| | 685 | compat_ulong_t, arg) |
| | 686 | { |
| | 687 | switch (cmd) { |
| | 688 | case F_GETLK64: |
| | 689 | case F_SETLK64: |
| | 690 | case F_SETLKW64: |
| | 691 | case F_OFD_GETLK: |
| | 692 | case F_OFD_SETLK: |
| | 693 | case F_OFD_SETLKW: |
| | 694 | return -EINVAL; |
| | 695 | } |
| | 696 | return do_compat_fcntl64(fd, cmd, arg); |
| | 697 | } |
| | 698 | #endif |
| | 699 | |
| | 700 | /* Table to convert sigio signal codes into poll band bitmaps */ |
| | 701 | |
| | 702 | static const __poll_t band_table[NSIGPOLL] = { |
| | 703 | EPOLLIN | EPOLLRDNORM, /* POLL_IN */ |
| | 704 | EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */ |
| | 705 | EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */ |
| | 706 | EPOLLERR, /* POLL_ERR */ |
| | 707 | EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */ |
| | 708 | EPOLLHUP | EPOLLERR /* POLL_HUP */ |
| | 709 | }; |
| | 710 | |
| | 711 | static inline int sigio_perm(struct task_struct *p, |
| | 712 | struct fown_struct *fown, int sig) |
| | 713 | { |
| | 714 | const struct cred *cred; |
| | 715 | int ret; |
| | 716 | |
| | 717 | rcu_read_lock(); |
| | 718 | cred = __task_cred(p); |
| | 719 | ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || |
| | 720 | uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || |
| | 721 | uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && |
| | 722 | !security_file_send_sigiotask(p, fown, sig)); |
| | 723 | rcu_read_unlock(); |
| | 724 | return ret; |
| | 725 | } |
| | 726 | |
| | 727 | static void send_sigio_to_task(struct task_struct *p, |
| | 728 | struct fown_struct *fown, |
| | 729 | int fd, int reason, enum pid_type type) |
| | 730 | { |
| | 731 | /* |
| | 732 | * F_SETSIG can change ->signum lockless in parallel, make |
| | 733 | * sure we read it once and use the same value throughout. |
| | 734 | */ |
| | 735 | int signum = READ_ONCE(fown->signum); |
| | 736 | |
| | 737 | if (!sigio_perm(p, fown, signum)) |
| | 738 | return; |
| | 739 | |
| | 740 | switch (signum) { |
| | 741 | kernel_siginfo_t si; |
| | 742 | default: |
| | 743 | /* Queue a rt signal with the appropriate fd as its |
| | 744 | value. We use SI_SIGIO as the source, not |
| | 745 | SI_KERNEL, since kernel signals always get |
| | 746 | delivered even if we can't queue. Failure to |
| | 747 | queue in this case _should_ be reported; we fall |
| | 748 | back to SIGIO in that case. --sct */ |
| | 749 | clear_siginfo(&si); |
| | 750 | si.si_signo = signum; |
| | 751 | si.si_errno = 0; |
| | 752 | si.si_code = reason; |
| | 753 | /* |
| | 754 | * Posix definies POLL_IN and friends to be signal |
| | 755 | * specific si_codes for SIG_POLL. Linux extended |
| | 756 | * these si_codes to other signals in a way that is |
| | 757 | * ambiguous if other signals also have signal |
| | 758 | * specific si_codes. In that case use SI_SIGIO instead |
| | 759 | * to remove the ambiguity. |
| | 760 | */ |
| | 761 | if ((signum != SIGPOLL) && sig_specific_sicodes(signum)) |
| | 762 | si.si_code = SI_SIGIO; |
| | 763 | |
| | 764 | /* Make sure we are called with one of the POLL_* |
| | 765 | reasons, otherwise we could leak kernel stack into |
| | 766 | userspace. */ |
| | 767 | BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL)); |
| | 768 | if (reason - POLL_IN >= NSIGPOLL) |
| | 769 | si.si_band = ~0L; |
| | 770 | else |
| | 771 | si.si_band = mangle_poll(band_table[reason - POLL_IN]); |
| | 772 | si.si_fd = fd; |
| | 773 | if (!do_send_sig_info(signum, &si, p, type)) |
| | 774 | break; |
| | 775 | /* fall-through - fall back on the old plain SIGIO signal */ |
| | 776 | case 0: |
| | 777 | do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type); |
| | 778 | } |
| | 779 | } |
| | 780 | |
| | 781 | void send_sigio(struct fown_struct *fown, int fd, int band) |
| | 782 | { |
| | 783 | struct task_struct *p; |
| | 784 | enum pid_type type; |
| | 785 | struct pid *pid; |
| | 786 | |
| | 787 | read_lock(&fown->lock); |
| | 788 | |
| | 789 | type = fown->pid_type; |
| | 790 | pid = fown->pid; |
| | 791 | if (!pid) |
| | 792 | goto out_unlock_fown; |
| | 793 | |
| | 794 | if (type <= PIDTYPE_TGID) { |
| | 795 | rcu_read_lock(); |
| | 796 | p = pid_task(pid, PIDTYPE_PID); |
| | 797 | if (p) |
| | 798 | send_sigio_to_task(p, fown, fd, band, type); |
| | 799 | rcu_read_unlock(); |
| | 800 | } else { |
| | 801 | read_lock(&tasklist_lock); |
| | 802 | do_each_pid_task(pid, type, p) { |
| | 803 | send_sigio_to_task(p, fown, fd, band, type); |
| | 804 | } while_each_pid_task(pid, type, p); |
| | 805 | read_unlock(&tasklist_lock); |
| | 806 | } |
| | 807 | out_unlock_fown: |
| | 808 | read_unlock(&fown->lock); |
| | 809 | } |
| | 810 | |
| | 811 | static void send_sigurg_to_task(struct task_struct *p, |
| | 812 | struct fown_struct *fown, enum pid_type type) |
| | 813 | { |
| | 814 | if (sigio_perm(p, fown, SIGURG)) |
| | 815 | do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type); |
| | 816 | } |
| | 817 | |
| | 818 | int send_sigurg(struct fown_struct *fown) |
| | 819 | { |
| | 820 | struct task_struct *p; |
| | 821 | enum pid_type type; |
| | 822 | struct pid *pid; |
| | 823 | int ret = 0; |
| | 824 | |
| | 825 | read_lock(&fown->lock); |
| | 826 | |
| | 827 | type = fown->pid_type; |
| | 828 | pid = fown->pid; |
| | 829 | if (!pid) |
| | 830 | goto out_unlock_fown; |
| | 831 | |
| | 832 | ret = 1; |
| | 833 | |
| | 834 | if (type <= PIDTYPE_TGID) { |
| | 835 | rcu_read_lock(); |
| | 836 | p = pid_task(pid, PIDTYPE_PID); |
| | 837 | if (p) |
| | 838 | send_sigurg_to_task(p, fown, type); |
| | 839 | rcu_read_unlock(); |
| | 840 | } else { |
| | 841 | read_lock(&tasklist_lock); |
| | 842 | do_each_pid_task(pid, type, p) { |
| | 843 | send_sigurg_to_task(p, fown, type); |
| | 844 | } while_each_pid_task(pid, type, p); |
| | 845 | read_unlock(&tasklist_lock); |
| | 846 | } |
| | 847 | out_unlock_fown: |
| | 848 | read_unlock(&fown->lock); |
| | 849 | return ret; |
| | 850 | } |
| | 851 | |
| | 852 | static DEFINE_SPINLOCK(fasync_lock); |
| | 853 | static struct kmem_cache *fasync_cache __read_mostly; |
| | 854 | |
| | 855 | static void fasync_free_rcu(struct rcu_head *head) |
| | 856 | { |
| | 857 | kmem_cache_free(fasync_cache, |
| | 858 | container_of(head, struct fasync_struct, fa_rcu)); |
| | 859 | } |
| | 860 | |
| | 861 | /* |
| | 862 | * Remove a fasync entry. If successfully removed, return |
| | 863 | * positive and clear the FASYNC flag. If no entry exists, |
| | 864 | * do nothing and return 0. |
| | 865 | * |
| | 866 | * NOTE! It is very important that the FASYNC flag always |
| | 867 | * match the state "is the filp on a fasync list". |
| | 868 | * |
| | 869 | */ |
| | 870 | int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) |
| | 871 | { |
| | 872 | struct fasync_struct *fa, **fp; |
| | 873 | int result = 0; |
| | 874 | |
| | 875 | spin_lock(&filp->f_lock); |
| | 876 | spin_lock(&fasync_lock); |
| | 877 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
| | 878 | if (fa->fa_file != filp) |
| | 879 | continue; |
| | 880 | |
| | 881 | write_lock_irq(&fa->fa_lock); |
| | 882 | fa->fa_file = NULL; |
| | 883 | write_unlock_irq(&fa->fa_lock); |
| | 884 | |
| | 885 | *fp = fa->fa_next; |
| | 886 | call_rcu(&fa->fa_rcu, fasync_free_rcu); |
| | 887 | filp->f_flags &= ~FASYNC; |
| | 888 | result = 1; |
| | 889 | break; |
| | 890 | } |
| | 891 | spin_unlock(&fasync_lock); |
| | 892 | spin_unlock(&filp->f_lock); |
| | 893 | return result; |
| | 894 | } |
| | 895 | |
| | 896 | struct fasync_struct *fasync_alloc(void) |
| | 897 | { |
| | 898 | return kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
| | 899 | } |
| | 900 | |
| | 901 | /* |
| | 902 | * NOTE! This can be used only for unused fasync entries: |
| | 903 | * entries that actually got inserted on the fasync list |
| | 904 | * need to be released by rcu - see fasync_remove_entry. |
| | 905 | */ |
| | 906 | void fasync_free(struct fasync_struct *new) |
| | 907 | { |
| | 908 | kmem_cache_free(fasync_cache, new); |
| | 909 | } |
| | 910 | |
| | 911 | /* |
| | 912 | * Insert a new entry into the fasync list. Return the pointer to the |
| | 913 | * old one if we didn't use the new one. |
| | 914 | * |
| | 915 | * NOTE! It is very important that the FASYNC flag always |
| | 916 | * match the state "is the filp on a fasync list". |
| | 917 | */ |
| | 918 | struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) |
| | 919 | { |
| | 920 | struct fasync_struct *fa, **fp; |
| | 921 | |
| | 922 | spin_lock(&filp->f_lock); |
| | 923 | spin_lock(&fasync_lock); |
| | 924 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
| | 925 | if (fa->fa_file != filp) |
| | 926 | continue; |
| | 927 | |
| | 928 | write_lock_irq(&fa->fa_lock); |
| | 929 | fa->fa_fd = fd; |
| | 930 | write_unlock_irq(&fa->fa_lock); |
| | 931 | goto out; |
| | 932 | } |
| | 933 | |
| | 934 | rwlock_init(&new->fa_lock); |
| | 935 | new->magic = FASYNC_MAGIC; |
| | 936 | new->fa_file = filp; |
| | 937 | new->fa_fd = fd; |
| | 938 | new->fa_next = *fapp; |
| | 939 | rcu_assign_pointer(*fapp, new); |
| | 940 | filp->f_flags |= FASYNC; |
| | 941 | |
| | 942 | out: |
| | 943 | spin_unlock(&fasync_lock); |
| | 944 | spin_unlock(&filp->f_lock); |
| | 945 | return fa; |
| | 946 | } |
| | 947 | |
| | 948 | /* |
| | 949 | * Add a fasync entry. Return negative on error, positive if |
| | 950 | * added, and zero if did nothing but change an existing one. |
| | 951 | */ |
| | 952 | static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) |
| | 953 | { |
| | 954 | struct fasync_struct *new; |
| | 955 | |
| | 956 | new = fasync_alloc(); |
| | 957 | if (!new) |
| | 958 | return -ENOMEM; |
| | 959 | |
| | 960 | /* |
| | 961 | * fasync_insert_entry() returns the old (update) entry if |
| | 962 | * it existed. |
| | 963 | * |
| | 964 | * So free the (unused) new entry and return 0 to let the |
| | 965 | * caller know that we didn't add any new fasync entries. |
| | 966 | */ |
| | 967 | if (fasync_insert_entry(fd, filp, fapp, new)) { |
| | 968 | fasync_free(new); |
| | 969 | return 0; |
| | 970 | } |
| | 971 | |
| | 972 | return 1; |
| | 973 | } |
| | 974 | |
| | 975 | /* |
| | 976 | * fasync_helper() is used by almost all character device drivers |
| | 977 | * to set up the fasync queue, and for regular files by the file |
| | 978 | * lease code. It returns negative on error, 0 if it did no changes |
| | 979 | * and positive if it added/deleted the entry. |
| | 980 | */ |
| | 981 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) |
| | 982 | { |
| | 983 | if (!on) |
| | 984 | return fasync_remove_entry(filp, fapp); |
| | 985 | return fasync_add_entry(fd, filp, fapp); |
| | 986 | } |
| | 987 | |
| | 988 | EXPORT_SYMBOL(fasync_helper); |
| | 989 | |
| | 990 | /* |
| | 991 | * rcu_read_lock() is held |
| | 992 | */ |
| | 993 | static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) |
| | 994 | { |
| | 995 | while (fa) { |
| | 996 | struct fown_struct *fown; |
| | 997 | |
| | 998 | if (fa->magic != FASYNC_MAGIC) { |
| | 999 | printk(KERN_ERR "kill_fasync: bad magic number in " |
| | 1000 | "fasync_struct!\n"); |
| | 1001 | return; |
| | 1002 | } |
| | 1003 | read_lock(&fa->fa_lock); |
| | 1004 | if (fa->fa_file) { |
| | 1005 | fown = &fa->fa_file->f_owner; |
| | 1006 | /* Don't send SIGURG to processes which have not set a |
| | 1007 | queued signum: SIGURG has its own default signalling |
| | 1008 | mechanism. */ |
| | 1009 | if (!(sig == SIGURG && fown->signum == 0)) |
| | 1010 | send_sigio(fown, fa->fa_fd, band); |
| | 1011 | } |
| | 1012 | read_unlock(&fa->fa_lock); |
| | 1013 | fa = rcu_dereference(fa->fa_next); |
| | 1014 | } |
| | 1015 | } |
| | 1016 | |
| | 1017 | void kill_fasync(struct fasync_struct **fp, int sig, int band) |
| | 1018 | { |
| | 1019 | /* First a quick test without locking: usually |
| | 1020 | * the list is empty. |
| | 1021 | */ |
| | 1022 | if (*fp) { |
| | 1023 | rcu_read_lock(); |
| | 1024 | kill_fasync_rcu(rcu_dereference(*fp), sig, band); |
| | 1025 | rcu_read_unlock(); |
| | 1026 | } |
| | 1027 | } |
| | 1028 | EXPORT_SYMBOL(kill_fasync); |
| | 1029 | |
| | 1030 | static int __init fcntl_init(void) |
| | 1031 | { |
| | 1032 | /* |
| | 1033 | * Please add new bits here to ensure allocation uniqueness. |
| | 1034 | * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY |
| | 1035 | * is defined as O_NONBLOCK on some platforms and not on others. |
| | 1036 | */ |
| | 1037 | BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != |
| | 1038 | HWEIGHT32( |
| | 1039 | (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) | |
| | 1040 | __FMODE_EXEC | __FMODE_NONOTIFY)); |
| | 1041 | |
| | 1042 | fasync_cache = kmem_cache_create("fasync_cache", |
| | 1043 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
| | 1044 | return 0; |
| | 1045 | } |
| | 1046 | |
| | 1047 | module_init(fcntl_init) |
projects / mirror_ubuntu-focal-kernel.git / blame_incremental