init/initramfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Many of the syscalls used in this file expect some of the arguments
   4  * to be __user pointers not __kernel pointers.  To limit the sparse
   5  * noise, turn off sparse checking for this file.
   6  */
   7 #ifdef __CHECKER__
   8 #undef __CHECKER__
   9 #warning "Sparse checking disabled for this file"
  10 #endif
  11
  12 #include <linux/init.h>
  13 #include <linux/fs.h>
  14 #include <linux/slab.h>
  15 #include <linux/types.h>
  16 #include <linux/fcntl.h>
  17 #include <linux/delay.h>
  18 #include <linux/string.h>
  19 #include <linux/dirent.h>
  20 #include <linux/syscalls.h>
  21 #include <linux/utime.h>
  22 #include <linux/file.h>
  23
  24 static ssize_t __init xwrite(int fd, const char *p, size_t count)
  25 {
  26         ssize_t out = 0;
  27
  28         /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
  29         while (count) {
  30                 ssize_t rv = sys_write(fd, p, count);
  31
  32                 if (rv < 0) {
  33                         if (rv == -EINTR || rv == -EAGAIN)
  34                                 continue;
  35                         return out ? out : rv;
  36                 } else if (rv == 0)
  37                         break;
  38
  39                 p += rv;
  40                 out += rv;
  41                 count -= rv;
  42         }
  43
  44         return out;
  45 }
  46
  47 static __initdata char *message;
  48 static void __init error(char *x)
  49 {
  50         if (!message)
  51                 message = x;
  52 }
  53
  54 /* link hash */
  55
  56 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  57
  58 static __initdata struct hash {
  59         int ino, minor, major;
  60         umode_t mode;
  61         struct hash *next;
  62         char name[N_ALIGN(PATH_MAX)];
  63 } *head[32];
  64
  65 static inline int hash(int major, int minor, int ino)
  66 {
  67         unsigned long tmp = ino + minor + (major << 3);
  68         tmp += tmp >> 5;
  69         return tmp & 31;
  70 }
  71
  72 static char __init *find_link(int major, int minor, int ino,
  73                               umode_t mode, char *name)
  74 {
  75         struct hash **p, *q;
  76         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  77                 if ((*p)->ino != ino)
  78                         continue;
  79                 if ((*p)->minor != minor)
  80                         continue;
  81                 if ((*p)->major != major)
  82                         continue;
  83                 if (((*p)->mode ^ mode) & S_IFMT)
  84                         continue;
  85                 return (*p)->name;
  86         }
  87         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  88         if (!q)
  89                 panic("can't allocate link hash entry");
  90         q->major = major;
  91         q->minor = minor;
  92         q->ino = ino;
  93         q->mode = mode;
  94         strcpy(q->name, name);
  95         q->next = NULL;
  96         *p = q;
  97         return NULL;
  98 }
  99
 100 static void __init free_hash(void)
 101 {
 102         struct hash **p, *q;
 103         for (p = head; p < head + 32; p++) {
 104                 while (*p) {
 105                         q = *p;
 106                         *p = q->next;
 107                         kfree(q);
 108                 }
 109         }
 110 }
 111
 112 static long __init do_utime(char *filename, time64_t mtime)
 113 {
 114         struct timespec64 t[2];
 115
 116         t[0].tv_sec = mtime;
 117         t[0].tv_nsec = 0;
 118         t[1].tv_sec = mtime;
 119         t[1].tv_nsec = 0;
 120
 121         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
 122 }
 123
 124 static __initdata LIST_HEAD(dir_list);
 125 struct dir_entry {
 126         struct list_head list;
 127         char *name;
 128         time64_t mtime;
 129 };
 130
 131 static void __init dir_add(const char *name, time64_t mtime)
 132 {
 133         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 134         if (!de)
 135                 panic("can't allocate dir_entry buffer");
 136         INIT_LIST_HEAD(&de->list);
 137         de->name = kstrdup(name, GFP_KERNEL);
 138         de->mtime = mtime;
 139         list_add(&de->list, &dir_list);
 140 }
 141
 142 static void __init dir_utime(void)
 143 {
 144         struct dir_entry *de, *tmp;
 145         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 146                 list_del(&de->list);
 147                 do_utime(de->name, de->mtime);
 148                 kfree(de->name);
 149                 kfree(de);
 150         }
 151 }
 152
 153 static __initdata time64_t mtime;
 154
 155 /* cpio header parsing */
 156
 157 static __initdata unsigned long ino, major, minor, nlink;
 158 static __initdata umode_t mode;
 159 static __initdata unsigned long body_len, name_len;
 160 static __initdata uid_t uid;
 161 static __initdata gid_t gid;
 162 static __initdata unsigned rdev;
 163
 164 static void __init parse_header(char *s)
 165 {
 166         unsigned long parsed[12];
 167         char buf[9];
 168         int i;
 169
 170         buf[8] = '\0';
 171         for (i = 0, s += 6; i < 12; i++, s += 8) {
 172                 memcpy(buf, s, 8);
 173                 parsed[i] = simple_strtoul(buf, NULL, 16);
 174         }
 175         ino = parsed[0];
 176         mode = parsed[1];
 177         uid = parsed[2];
 178         gid = parsed[3];
 179         nlink = parsed[4];
 180         mtime = parsed[5]; /* breaks in y2106 */
 181         body_len = parsed[6];
 182         major = parsed[7];
 183         minor = parsed[8];
 184         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 185         name_len = parsed[11];
 186 }
 187
 188 /* FSM */
 189
 190 static __initdata enum state {
 191         Start,
 192         Collect,
 193         GotHeader,
 194         SkipIt,
 195         GotName,
 196         CopyFile,
 197         GotSymlink,
 198         Reset
 199 } state, next_state;
 200
 201 static __initdata char *victim;
 202 static unsigned long byte_count __initdata;
 203 static __initdata loff_t this_header, next_header;
 204
 205 static inline void __init eat(unsigned n)
 206 {
 207         victim += n;
 208         this_header += n;
 209         byte_count -= n;
 210 }
 211
 212 static __initdata char *vcollected;
 213 static __initdata char *collected;
 214 static long remains __initdata;
 215 static __initdata char *collect;
 216
 217 static void __init read_into(char *buf, unsigned size, enum state next)
 218 {
 219         if (byte_count >= size) {
 220                 collected = victim;
 221                 eat(size);
 222                 state = next;
 223         } else {
 224                 collect = collected = buf;
 225                 remains = size;
 226                 next_state = next;
 227                 state = Collect;
 228         }
 229 }
 230
 231 static __initdata char *header_buf, *symlink_buf, *name_buf;
 232
 233 static int __init do_start(void)
 234 {
 235         read_into(header_buf, 110, GotHeader);
 236         return 0;
 237 }
 238
 239 static int __init do_collect(void)
 240 {
 241         unsigned long n = remains;
 242         if (byte_count < n)
 243                 n = byte_count;
 244         memcpy(collect, victim, n);
 245         eat(n);
 246         collect += n;
 247         if ((remains -= n) != 0)
 248                 return 1;
 249         state = next_state;
 250         return 0;
 251 }
 252
 253 static int __init do_header(void)
 254 {
 255         if (memcmp(collected, "070707", 6)==0) {
 256                 error("incorrect cpio method used: use -H newc option");
 257                 return 1;
 258         }
 259         if (memcmp(collected, "070701", 6)) {
 260                 error("no cpio magic");
 261                 return 1;
 262         }
 263         parse_header(collected);
 264         next_header = this_header + N_ALIGN(name_len) + body_len;
 265         next_header = (next_header + 3) & ~3;
 266         state = SkipIt;
 267         if (name_len <= 0 || name_len > PATH_MAX)
 268                 return 0;
 269         if (S_ISLNK(mode)) {
 270                 if (body_len > PATH_MAX)
 271                         return 0;
 272                 collect = collected = symlink_buf;
 273                 remains = N_ALIGN(name_len) + body_len;
 274                 next_state = GotSymlink;
 275                 state = Collect;
 276                 return 0;
 277         }
 278         if (S_ISREG(mode) || !body_len)
 279                 read_into(name_buf, N_ALIGN(name_len), GotName);
 280         return 0;
 281 }
 282
 283 static int __init do_skip(void)
 284 {
 285         if (this_header + byte_count < next_header) {
 286                 eat(byte_count);
 287                 return 1;
 288         } else {
 289                 eat(next_header - this_header);
 290                 state = next_state;
 291                 return 0;
 292         }
 293 }
 294
 295 static int __init do_reset(void)
 296 {
 297         while (byte_count && *victim == '\0')
 298                 eat(1);
 299         if (byte_count && (this_header & 3))
 300                 error("broken padding");
 301         return 1;
 302 }
 303
 304 static int __init maybe_link(void)
 305 {
 306         if (nlink >= 2) {
 307                 char *old = find_link(major, minor, ino, mode, collected);
 308                 if (old)
 309                         return (sys_link(old, collected) < 0) ? -1 : 1;
 310         }
 311         return 0;
 312 }
 313
 314 static void __init clean_path(char *path, umode_t fmode)
 315 {
 316         struct kstat st;
 317
 318         if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) {
 319                 if (S_ISDIR(st.mode))
 320                         sys_rmdir(path);
 321                 else
 322                         sys_unlink(path);
 323         }
 324 }
 325
 326 static __initdata int wfd;
 327
 328 static int __init do_name(void)
 329 {
 330         state = SkipIt;
 331         next_state = Reset;
 332         if (strcmp(collected, "TRAILER!!!") == 0) {
 333                 free_hash();
 334                 return 0;
 335         }
 336         clean_path(collected, mode);
 337         if (S_ISREG(mode)) {
 338                 int ml = maybe_link();
 339                 if (ml >= 0) {
 340                         int openflags = O_WRONLY|O_CREAT;
 341                         if (ml != 1)
 342                                 openflags |= O_TRUNC;
 343                         wfd = sys_open(collected, openflags, mode);
 344
 345                         if (wfd >= 0) {
 346                                 sys_fchown(wfd, uid, gid);
 347                                 sys_fchmod(wfd, mode);
 348                                 if (body_len)
 349                                         sys_ftruncate(wfd, body_len);
 350                                 vcollected = kstrdup(collected, GFP_KERNEL);
 351                                 state = CopyFile;
 352                         }
 353                 }
 354         } else if (S_ISDIR(mode)) {
 355                 sys_mkdir(collected, mode);
 356                 sys_chown(collected, uid, gid);
 357                 sys_chmod(collected, mode);
 358                 dir_add(collected, mtime);
 359         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 360                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 361                 if (maybe_link() == 0) {
 362                         sys_mknod(collected, mode, rdev);
 363                         sys_chown(collected, uid, gid);
 364                         sys_chmod(collected, mode);
 365                         do_utime(collected, mtime);
 366                 }
 367         }
 368         return 0;
 369 }
 370
 371 static int __init do_copy(void)
 372 {
 373         if (byte_count >= body_len) {
 374                 if (xwrite(wfd, victim, body_len) != body_len)
 375                         error("write error");
 376                 sys_close(wfd);
 377                 do_utime(vcollected, mtime);
 378                 kfree(vcollected);
 379                 eat(body_len);
 380                 state = SkipIt;
 381                 return 0;
 382         } else {
 383                 if (xwrite(wfd, victim, byte_count) != byte_count)
 384                         error("write error");
 385                 body_len -= byte_count;
 386                 eat(byte_count);
 387                 return 1;
 388         }
 389 }
 390
 391 static int __init do_symlink(void)
 392 {
 393         collected[N_ALIGN(name_len) + body_len] = '\0';
 394         clean_path(collected, 0);
 395         sys_symlink(collected + N_ALIGN(name_len), collected);
 396         sys_lchown(collected, uid, gid);
 397         do_utime(collected, mtime);
 398         state = SkipIt;
 399         next_state = Reset;
 400         return 0;
 401 }
 402
 403 static __initdata int (*actions[])(void) = {
 404         [Start]         = do_start,
 405         [Collect]       = do_collect,
 406         [GotHeader]     = do_header,
 407         [SkipIt]        = do_skip,
 408         [GotName]       = do_name,
 409         [CopyFile]      = do_copy,
 410         [GotSymlink]    = do_symlink,
 411         [Reset]         = do_reset,
 412 };
 413
 414 static long __init write_buffer(char *buf, unsigned long len)
 415 {
 416         byte_count = len;
 417         victim = buf;
 418
 419         while (!actions[state]())
 420                 ;
 421         return len - byte_count;
 422 }
 423
 424 static long __init flush_buffer(void *bufv, unsigned long len)
 425 {
 426         char *buf = (char *) bufv;
 427         long written;
 428         long origLen = len;
 429         if (message)
 430                 return -1;
 431         while ((written = write_buffer(buf, len)) < len && !message) {
 432                 char c = buf[written];
 433                 if (c == '0') {
 434                         buf += written;
 435                         len -= written;
 436                         state = Start;
 437                 } else if (c == 0) {
 438                         buf += written;
 439                         len -= written;
 440                         state = Reset;
 441                 } else
 442                         error("junk in compressed archive");
 443         }
 444         return origLen;
 445 }
 446
 447 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
 448
 449 #include <linux/decompress/generic.h>
 450
 451 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 452 {
 453         long written;
 454         decompress_fn decompress;
 455         const char *compress_name;
 456         static __initdata char msg_buf[64];
 457
 458         header_buf = kmalloc(110, GFP_KERNEL);
 459         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 460         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 461
 462         if (!header_buf || !symlink_buf || !name_buf)
 463                 panic("can't allocate buffers");
 464
 465         state = Start;
 466         this_header = 0;
 467         message = NULL;
 468         while (!message && len) {
 469                 loff_t saved_offset = this_header;
 470                 if (*buf == '0' && !(this_header & 3)) {
 471                         state = Start;
 472                         written = write_buffer(buf, len);
 473                         buf += written;
 474                         len -= written;
 475                         continue;
 476                 }
 477                 if (!*buf) {
 478                         buf++;
 479                         len--;
 480                         this_header++;
 481                         continue;
 482                 }
 483                 this_header = 0;
 484                 decompress = decompress_method(buf, len, &compress_name);
 485                 pr_debug("Detected %s compressed data\n", compress_name);
 486                 if (decompress) {
 487                         int res = decompress(buf, len, NULL, flush_buffer, NULL,
 488                                    &my_inptr, error);
 489                         if (res)
 490                                 error("decompressor failed");
 491                 } else if (compress_name) {
 492                         if (!message) {
 493                                 snprintf(msg_buf, sizeof msg_buf,
 494                                          "compression method %s not configured",
 495                                          compress_name);
 496                                 message = msg_buf;
 497                         }
 498                 } else
 499                         error("junk in compressed archive");
 500                 if (state != Reset)
 501                         error("junk in compressed archive");
 502                 this_header = saved_offset + my_inptr;
 503                 buf += my_inptr;
 504                 len -= my_inptr;
 505         }
 506         dir_utime();
 507         kfree(name_buf);
 508         kfree(symlink_buf);
 509         kfree(header_buf);
 510         return message;
 511 }
 512
 513 static int __initdata do_retain_initrd;
 514
 515 static int __init retain_initrd_param(char *str)
 516 {
 517         if (*str)
 518                 return 0;
 519         do_retain_initrd = 1;
 520         return 1;
 521 }
 522 __setup("retain_initrd", retain_initrd_param);
 523
 524 extern char __initramfs_start[];
 525 extern unsigned long __initramfs_size;
 526 #include <linux/initrd.h>
 527 #include <linux/kexec.h>
 528
 529 static void __init free_initrd(void)
 530 {
 531 #ifdef CONFIG_KEXEC_CORE
 532         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 533         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 534 #endif
 535         if (do_retain_initrd)
 536                 goto skip;
 537
 538 #ifdef CONFIG_KEXEC_CORE
 539         /*
 540          * If the initrd region is overlapped with crashkernel reserved region,
 541          * free only memory that is not part of crashkernel region.
 542          */
 543         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 544                 /*
 545                  * Initialize initrd memory region since the kexec boot does
 546                  * not do.
 547                  */
 548                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 549                 if (initrd_start < crashk_start)
 550                         free_initrd_mem(initrd_start, crashk_start);
 551                 if (initrd_end > crashk_end)
 552                         free_initrd_mem(crashk_end, initrd_end);
 553         } else
 554 #endif
 555                 free_initrd_mem(initrd_start, initrd_end);
 556 skip:
 557         initrd_start = 0;
 558         initrd_end = 0;
 559 }
 560
 561 #ifdef CONFIG_BLK_DEV_RAM
 562 #define BUF_SIZE 1024
 563 static void __init clean_rootfs(void)
 564 {
 565         int fd;
 566         void *buf;
 567         struct linux_dirent64 *dirp;
 568         int num;
 569
 570         fd = sys_open("/", O_RDONLY, 0);
 571         WARN_ON(fd < 0);
 572         if (fd < 0)
 573                 return;
 574         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 575         WARN_ON(!buf);
 576         if (!buf) {
 577                 sys_close(fd);
 578                 return;
 579         }
 580
 581         dirp = buf;
 582         num = sys_getdents64(fd, dirp, BUF_SIZE);
 583         while (num > 0) {
 584                 while (num > 0) {
 585                         struct kstat st;
 586                         int ret;
 587
 588                         ret = vfs_lstat(dirp->d_name, &st);
 589                         WARN_ON_ONCE(ret);
 590                         if (!ret) {
 591                                 if (S_ISDIR(st.mode))
 592                                         sys_rmdir(dirp->d_name);
 593                                 else
 594                                         sys_unlink(dirp->d_name);
 595                         }
 596
 597                         num -= dirp->d_reclen;
 598                         dirp = (void *)dirp + dirp->d_reclen;
 599                 }
 600                 dirp = buf;
 601                 memset(buf, 0, BUF_SIZE);
 602                 num = sys_getdents64(fd, dirp, BUF_SIZE);
 603         }
 604
 605         sys_close(fd);
 606         kfree(buf);
 607 }
 608 #endif
 609
 610 static int __init populate_rootfs(void)
 611 {
 612         /* Load the built in initramfs */
 613         char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 614         if (err)
 615                 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
 616         /* If available load the bootloader supplied initrd */
 617         if (initrd_start && !IS_ENABLED(CONFIG_INITRAMFS_FORCE)) {
 618 #ifdef CONFIG_BLK_DEV_RAM
 619                 int fd;
 620                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 621                 err = unpack_to_rootfs((char *)initrd_start,
 622                         initrd_end - initrd_start);
 623                 if (!err) {
 624                         free_initrd();
 625                         goto done;
 626                 } else {
 627                         clean_rootfs();
 628                         unpack_to_rootfs(__initramfs_start, __initramfs_size);
 629                 }
 630                 printk(KERN_INFO "rootfs image is not initramfs (%s)"
 631                                 "; looks like an initrd\n", err);
 632                 fd = sys_open("/initrd.image",
 633                               O_WRONLY|O_CREAT, 0700);
 634                 if (fd >= 0) {
 635                         ssize_t written = xwrite(fd, (char *)initrd_start,
 636                                                 initrd_end - initrd_start);
 637
 638                         if (written != initrd_end - initrd_start)
 639                                 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 640                                        written, initrd_end - initrd_start);
 641
 642                         sys_close(fd);
 643                         free_initrd();
 644                 }
 645         done:
 646                 /* empty statement */;
 647 #else
 648                 printk(KERN_INFO "Unpacking initramfs...\n");
 649                 err = unpack_to_rootfs((char *)initrd_start,
 650                         initrd_end - initrd_start);
 651                 if (err)
 652                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 653                 free_initrd();
 654 #endif
 655         }
 656         flush_delayed_fput();
 657         /*
 658          * Try loading default modules from initramfs.  This gives
 659          * us a chance to load before device_initcalls.
 660          */
 661         load_default_modules();
 662
 663         return 0;
 664 }
 665 rootfs_initcall(populate_rootfs);