init/initramfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/init.h>
   3 #include <linux/async.h>
   4 #include <linux/fs.h>
   5 #include <linux/slab.h>
   6 #include <linux/types.h>
   7 #include <linux/fcntl.h>
   8 #include <linux/delay.h>
   9 #include <linux/string.h>
  10 #include <linux/dirent.h>
  11 #include <linux/syscalls.h>
  12 #include <linux/utime.h>
  13 #include <linux/file.h>
  14 #include <linux/memblock.h>
  15 #include <linux/mm.h>
  16 #include <linux/namei.h>
  17 #include <linux/init_syscalls.h>
  18 #include <linux/umh.h>
  19
  20 static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
  21                 loff_t *pos)
  22 {
  23         ssize_t out = 0;
  24
  25         /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
  26         while (count) {
  27                 ssize_t rv = kernel_write(file, p, count, pos);
  28
  29                 if (rv < 0) {
  30                         if (rv == -EINTR || rv == -EAGAIN)
  31                                 continue;
  32                         return out ? out : rv;
  33                 } else if (rv == 0)
  34                         break;
  35
  36                 p += rv;
  37                 out += rv;
  38                 count -= rv;
  39         }
  40
  41         return out;
  42 }
  43
  44 static __initdata char *message;
  45 static void __init error(char *x)
  46 {
  47         if (!message)
  48                 message = x;
  49 }
  50
  51 static void panic_show_mem(const char *fmt, ...)
  52 {
  53         va_list args;
  54
  55         show_mem(0, NULL);
  56         va_start(args, fmt);
  57         panic(fmt, args);
  58         va_end(args);
  59 }
  60
  61 /* link hash */
  62
  63 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  64
  65 static __initdata struct hash {
  66         int ino, minor, major;
  67         umode_t mode;
  68         struct hash *next;
  69         char name[N_ALIGN(PATH_MAX)];
  70 } *head[32];
  71
  72 static inline int hash(int major, int minor, int ino)
  73 {
  74         unsigned long tmp = ino + minor + (major << 3);
  75         tmp += tmp >> 5;
  76         return tmp & 31;
  77 }
  78
  79 static char __init *find_link(int major, int minor, int ino,
  80                               umode_t mode, char *name)
  81 {
  82         struct hash **p, *q;
  83         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  84                 if ((*p)->ino != ino)
  85                         continue;
  86                 if ((*p)->minor != minor)
  87                         continue;
  88                 if ((*p)->major != major)
  89                         continue;
  90                 if (((*p)->mode ^ mode) & S_IFMT)
  91                         continue;
  92                 return (*p)->name;
  93         }
  94         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  95         if (!q)
  96                 panic_show_mem("can't allocate link hash entry");
  97         q->major = major;
  98         q->minor = minor;
  99         q->ino = ino;
 100         q->mode = mode;
 101         strcpy(q->name, name);
 102         q->next = NULL;
 103         *p = q;
 104         return NULL;
 105 }
 106
 107 static void __init free_hash(void)
 108 {
 109         struct hash **p, *q;
 110         for (p = head; p < head + 32; p++) {
 111                 while (*p) {
 112                         q = *p;
 113                         *p = q->next;
 114                         kfree(q);
 115                 }
 116         }
 117 }
 118
 119 static long __init do_utime(char *filename, time64_t mtime)
 120 {
 121         struct timespec64 t[2];
 122
 123         t[0].tv_sec = mtime;
 124         t[0].tv_nsec = 0;
 125         t[1].tv_sec = mtime;
 126         t[1].tv_nsec = 0;
 127         return init_utimes(filename, t);
 128 }
 129
 130 static __initdata LIST_HEAD(dir_list);
 131 struct dir_entry {
 132         struct list_head list;
 133         char *name;
 134         time64_t mtime;
 135 };
 136
 137 static void __init dir_add(const char *name, time64_t mtime)
 138 {
 139         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 140         if (!de)
 141                 panic_show_mem("can't allocate dir_entry buffer");
 142         INIT_LIST_HEAD(&de->list);
 143         de->name = kstrdup(name, GFP_KERNEL);
 144         de->mtime = mtime;
 145         list_add(&de->list, &dir_list);
 146 }
 147
 148 static void __init dir_utime(void)
 149 {
 150         struct dir_entry *de, *tmp;
 151         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 152                 list_del(&de->list);
 153                 do_utime(de->name, de->mtime);
 154                 kfree(de->name);
 155                 kfree(de);
 156         }
 157 }
 158
 159 static __initdata time64_t mtime;
 160
 161 /* cpio header parsing */
 162
 163 static __initdata unsigned long ino, major, minor, nlink;
 164 static __initdata umode_t mode;
 165 static __initdata unsigned long body_len, name_len;
 166 static __initdata uid_t uid;
 167 static __initdata gid_t gid;
 168 static __initdata unsigned rdev;
 169
 170 static void __init parse_header(char *s)
 171 {
 172         unsigned long parsed[12];
 173         char buf[9];
 174         int i;
 175
 176         buf[8] = '\0';
 177         for (i = 0, s += 6; i < 12; i++, s += 8) {
 178                 memcpy(buf, s, 8);
 179                 parsed[i] = simple_strtoul(buf, NULL, 16);
 180         }
 181         ino = parsed[0];
 182         mode = parsed[1];
 183         uid = parsed[2];
 184         gid = parsed[3];
 185         nlink = parsed[4];
 186         mtime = parsed[5]; /* breaks in y2106 */
 187         body_len = parsed[6];
 188         major = parsed[7];
 189         minor = parsed[8];
 190         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 191         name_len = parsed[11];
 192 }
 193
 194 /* FSM */
 195
 196 static __initdata enum state {
 197         Start,
 198         Collect,
 199         GotHeader,
 200         SkipIt,
 201         GotName,
 202         CopyFile,
 203         GotSymlink,
 204         Reset
 205 } state, next_state;
 206
 207 static __initdata char *victim;
 208 static unsigned long byte_count __initdata;
 209 static __initdata loff_t this_header, next_header;
 210
 211 static inline void __init eat(unsigned n)
 212 {
 213         victim += n;
 214         this_header += n;
 215         byte_count -= n;
 216 }
 217
 218 static __initdata char *collected;
 219 static long remains __initdata;
 220 static __initdata char *collect;
 221
 222 static void __init read_into(char *buf, unsigned size, enum state next)
 223 {
 224         if (byte_count >= size) {
 225                 collected = victim;
 226                 eat(size);
 227                 state = next;
 228         } else {
 229                 collect = collected = buf;
 230                 remains = size;
 231                 next_state = next;
 232                 state = Collect;
 233         }
 234 }
 235
 236 static __initdata char *header_buf, *symlink_buf, *name_buf;
 237
 238 static int __init do_start(void)
 239 {
 240         read_into(header_buf, 110, GotHeader);
 241         return 0;
 242 }
 243
 244 static int __init do_collect(void)
 245 {
 246         unsigned long n = remains;
 247         if (byte_count < n)
 248                 n = byte_count;
 249         memcpy(collect, victim, n);
 250         eat(n);
 251         collect += n;
 252         if ((remains -= n) != 0)
 253                 return 1;
 254         state = next_state;
 255         return 0;
 256 }
 257
 258 static int __init do_header(void)
 259 {
 260         if (memcmp(collected, "070707", 6)==0) {
 261                 error("incorrect cpio method used: use -H newc option");
 262                 return 1;
 263         }
 264         if (memcmp(collected, "070701", 6)) {
 265                 error("no cpio magic");
 266                 return 1;
 267         }
 268         parse_header(collected);
 269         next_header = this_header + N_ALIGN(name_len) + body_len;
 270         next_header = (next_header + 3) & ~3;
 271         state = SkipIt;
 272         if (name_len <= 0 || name_len > PATH_MAX)
 273                 return 0;
 274         if (S_ISLNK(mode)) {
 275                 if (body_len > PATH_MAX)
 276                         return 0;
 277                 collect = collected = symlink_buf;
 278                 remains = N_ALIGN(name_len) + body_len;
 279                 next_state = GotSymlink;
 280                 state = Collect;
 281                 return 0;
 282         }
 283         if (S_ISREG(mode) || !body_len)
 284                 read_into(name_buf, N_ALIGN(name_len), GotName);
 285         return 0;
 286 }
 287
 288 static int __init do_skip(void)
 289 {
 290         if (this_header + byte_count < next_header) {
 291                 eat(byte_count);
 292                 return 1;
 293         } else {
 294                 eat(next_header - this_header);
 295                 state = next_state;
 296                 return 0;
 297         }
 298 }
 299
 300 static int __init do_reset(void)
 301 {
 302         while (byte_count && *victim == '\0')
 303                 eat(1);
 304         if (byte_count && (this_header & 3))
 305                 error("broken padding");
 306         return 1;
 307 }
 308
 309 static void __init clean_path(char *path, umode_t fmode)
 310 {
 311         struct kstat st;
 312
 313         if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
 314             (st.mode ^ fmode) & S_IFMT) {
 315                 if (S_ISDIR(st.mode))
 316                         init_rmdir(path);
 317                 else
 318                         init_unlink(path);
 319         }
 320 }
 321
 322 static int __init maybe_link(void)
 323 {
 324         if (nlink >= 2) {
 325                 char *old = find_link(major, minor, ino, mode, collected);
 326                 if (old) {
 327                         clean_path(collected, 0);
 328                         return (init_link(old, collected) < 0) ? -1 : 1;
 329                 }
 330         }
 331         return 0;
 332 }
 333
 334 static __initdata struct file *wfile;
 335 static __initdata loff_t wfile_pos;
 336
 337 static int __init do_name(void)
 338 {
 339         state = SkipIt;
 340         next_state = Reset;
 341         if (strcmp(collected, "TRAILER!!!") == 0) {
 342                 free_hash();
 343                 return 0;
 344         }
 345         clean_path(collected, mode);
 346         if (S_ISREG(mode)) {
 347                 int ml = maybe_link();
 348                 if (ml >= 0) {
 349                         int openflags = O_WRONLY|O_CREAT;
 350                         if (ml != 1)
 351                                 openflags |= O_TRUNC;
 352                         wfile = filp_open(collected, openflags, mode);
 353                         if (IS_ERR(wfile))
 354                                 return 0;
 355                         wfile_pos = 0;
 356
 357                         vfs_fchown(wfile, uid, gid);
 358                         vfs_fchmod(wfile, mode);
 359                         if (body_len)
 360                                 vfs_truncate(&wfile->f_path, body_len);
 361                         state = CopyFile;
 362                 }
 363         } else if (S_ISDIR(mode)) {
 364                 init_mkdir(collected, mode);
 365                 init_chown(collected, uid, gid, 0);
 366                 init_chmod(collected, mode);
 367                 dir_add(collected, mtime);
 368         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 369                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 370                 if (maybe_link() == 0) {
 371                         init_mknod(collected, mode, rdev);
 372                         init_chown(collected, uid, gid, 0);
 373                         init_chmod(collected, mode);
 374                         do_utime(collected, mtime);
 375                 }
 376         }
 377         return 0;
 378 }
 379
 380 static int __init do_copy(void)
 381 {
 382         if (byte_count >= body_len) {
 383                 struct timespec64 t[2] = { };
 384                 if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
 385                         error("write error");
 386
 387                 t[0].tv_sec = mtime;
 388                 t[1].tv_sec = mtime;
 389                 vfs_utimes(&wfile->f_path, t);
 390
 391                 fput(wfile);
 392                 eat(body_len);
 393                 state = SkipIt;
 394                 return 0;
 395         } else {
 396                 if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
 397                         error("write error");
 398                 body_len -= byte_count;
 399                 eat(byte_count);
 400                 return 1;
 401         }
 402 }
 403
 404 static int __init do_symlink(void)
 405 {
 406         collected[N_ALIGN(name_len) + body_len] = '\0';
 407         clean_path(collected, 0);
 408         init_symlink(collected + N_ALIGN(name_len), collected);
 409         init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
 410         do_utime(collected, mtime);
 411         state = SkipIt;
 412         next_state = Reset;
 413         return 0;
 414 }
 415
 416 static __initdata int (*actions[])(void) = {
 417         [Start]         = do_start,
 418         [Collect]       = do_collect,
 419         [GotHeader]     = do_header,
 420         [SkipIt]        = do_skip,
 421         [GotName]       = do_name,
 422         [CopyFile]      = do_copy,
 423         [GotSymlink]    = do_symlink,
 424         [Reset]         = do_reset,
 425 };
 426
 427 static long __init write_buffer(char *buf, unsigned long len)
 428 {
 429         byte_count = len;
 430         victim = buf;
 431
 432         while (!actions[state]())
 433                 ;
 434         return len - byte_count;
 435 }
 436
 437 static long __init flush_buffer(void *bufv, unsigned long len)
 438 {
 439         char *buf = (char *) bufv;
 440         long written;
 441         long origLen = len;
 442         if (message)
 443                 return -1;
 444         while ((written = write_buffer(buf, len)) < len && !message) {
 445                 char c = buf[written];
 446                 if (c == '0') {
 447                         buf += written;
 448                         len -= written;
 449                         state = Start;
 450                 } else if (c == 0) {
 451                         buf += written;
 452                         len -= written;
 453                         state = Reset;
 454                 } else
 455                         error("junk within compressed archive");
 456         }
 457         return origLen;
 458 }
 459
 460 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
 461
 462 #include <linux/decompress/generic.h>
 463
 464 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 465 {
 466         long written;
 467         decompress_fn decompress;
 468         const char *compress_name;
 469         static __initdata char msg_buf[64];
 470
 471         header_buf = kmalloc(110, GFP_KERNEL);
 472         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 473         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 474
 475         if (!header_buf || !symlink_buf || !name_buf)
 476                 panic_show_mem("can't allocate buffers");
 477
 478         state = Start;
 479         this_header = 0;
 480         message = NULL;
 481         while (!message && len) {
 482                 loff_t saved_offset = this_header;
 483                 if (*buf == '0' && !(this_header & 3)) {
 484                         state = Start;
 485                         written = write_buffer(buf, len);
 486                         buf += written;
 487                         len -= written;
 488                         continue;
 489                 }
 490                 if (!*buf) {
 491                         buf++;
 492                         len--;
 493                         this_header++;
 494                         continue;
 495                 }
 496                 this_header = 0;
 497                 decompress = decompress_method(buf, len, &compress_name);
 498                 pr_debug("Detected %s compressed data\n", compress_name);
 499                 if (decompress) {
 500                         int res = decompress(buf, len, NULL, flush_buffer, NULL,
 501                                    &my_inptr, error);
 502                         if (res)
 503                                 error("decompressor failed");
 504                 } else if (compress_name) {
 505                         if (!message) {
 506                                 snprintf(msg_buf, sizeof msg_buf,
 507                                          "compression method %s not configured",
 508                                          compress_name);
 509                                 message = msg_buf;
 510                         }
 511                 } else
 512                         error("invalid magic at start of compressed archive");
 513                 if (state != Reset)
 514                         error("junk at the end of compressed archive");
 515                 this_header = saved_offset + my_inptr;
 516                 buf += my_inptr;
 517                 len -= my_inptr;
 518         }
 519         dir_utime();
 520         kfree(name_buf);
 521         kfree(symlink_buf);
 522         kfree(header_buf);
 523         return message;
 524 }
 525
 526 static int __initdata do_retain_initrd;
 527
 528 static int __init retain_initrd_param(char *str)
 529 {
 530         if (*str)
 531                 return 0;
 532         do_retain_initrd = 1;
 533         return 1;
 534 }
 535 __setup("retain_initrd", retain_initrd_param);
 536
 537 #ifdef CONFIG_ARCH_HAS_KEEPINITRD
 538 static int __init keepinitrd_setup(char *__unused)
 539 {
 540         do_retain_initrd = 1;
 541         return 1;
 542 }
 543 __setup("keepinitrd", keepinitrd_setup);
 544 #endif
 545
 546 static bool __initdata initramfs_async = true;
 547 static int __init initramfs_async_setup(char *str)
 548 {
 549         strtobool(str, &initramfs_async);
 550         return 1;
 551 }
 552 __setup("initramfs_async=", initramfs_async_setup);
 553
 554 extern char __initramfs_start[];
 555 extern unsigned long __initramfs_size;
 556 #include <linux/initrd.h>
 557 #include <linux/kexec.h>
 558
 559 void __init reserve_initrd_mem(void)
 560 {
 561         phys_addr_t start;
 562         unsigned long size;
 563
 564         /* Ignore the virtul address computed during device tree parsing */
 565         initrd_start = initrd_end = 0;
 566
 567         if (!phys_initrd_size)
 568                 return;
 569         /*
 570          * Round the memory region to page boundaries as per free_initrd_mem()
 571          * This allows us to detect whether the pages overlapping the initrd
 572          * are in use, but more importantly, reserves the entire set of pages
 573          * as we don't want these pages allocated for other purposes.
 574          */
 575         start = round_down(phys_initrd_start, PAGE_SIZE);
 576         size = phys_initrd_size + (phys_initrd_start - start);
 577         size = round_up(size, PAGE_SIZE);
 578
 579         if (!memblock_is_region_memory(start, size)) {
 580                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
 581                        (u64)start, size);
 582                 goto disable;
 583         }
 584
 585         if (memblock_is_region_reserved(start, size)) {
 586                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
 587                        (u64)start, size);
 588                 goto disable;
 589         }
 590
 591         memblock_reserve(start, size);
 592         /* Now convert initrd to virtual addresses */
 593         initrd_start = (unsigned long)__va(phys_initrd_start);
 594         initrd_end = initrd_start + phys_initrd_size;
 595         initrd_below_start_ok = 1;
 596
 597         return;
 598 disable:
 599         pr_cont(" - disabling initrd\n");
 600         initrd_start = 0;
 601         initrd_end = 0;
 602 }
 603
 604 void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
 605 {
 606 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
 607         unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
 608         unsigned long aligned_end = ALIGN(end, PAGE_SIZE);
 609
 610         memblock_free(__pa(aligned_start), aligned_end - aligned_start);
 611 #endif
 612
 613         free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
 614                         "initrd");
 615 }
 616
 617 #ifdef CONFIG_KEXEC_CORE
 618 static bool __init kexec_free_initrd(void)
 619 {
 620         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 621         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 622
 623         /*
 624          * If the initrd region is overlapped with crashkernel reserved region,
 625          * free only memory that is not part of crashkernel region.
 626          */
 627         if (initrd_start >= crashk_end || initrd_end <= crashk_start)
 628                 return false;
 629
 630         /*
 631          * Initialize initrd memory region since the kexec boot does not do.
 632          */
 633         memset((void *)initrd_start, 0, initrd_end - initrd_start);
 634         if (initrd_start < crashk_start)
 635                 free_initrd_mem(initrd_start, crashk_start);
 636         if (initrd_end > crashk_end)
 637                 free_initrd_mem(crashk_end, initrd_end);
 638         return true;
 639 }
 640 #else
 641 static inline bool kexec_free_initrd(void)
 642 {
 643         return false;
 644 }
 645 #endif /* CONFIG_KEXEC_CORE */
 646
 647 #ifdef CONFIG_BLK_DEV_RAM
 648 static void __init populate_initrd_image(char *err)
 649 {
 650         ssize_t written;
 651         struct file *file;
 652         loff_t pos = 0;
 653
 654         unpack_to_rootfs(__initramfs_start, __initramfs_size);
 655
 656         printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
 657                         err);
 658         file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
 659         if (IS_ERR(file))
 660                 return;
 661
 662         written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
 663                         &pos);
 664         if (written != initrd_end - initrd_start)
 665                 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 666                        written, initrd_end - initrd_start);
 667         fput(file);
 668 }
 669 #endif /* CONFIG_BLK_DEV_RAM */
 670
 671 static void __init do_populate_rootfs(void *unused, async_cookie_t cookie)
 672 {
 673         /* Load the built in initramfs */
 674         char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 675         if (err)
 676                 panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */
 677
 678         if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
 679                 goto done;
 680
 681         if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
 682                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 683         else
 684                 printk(KERN_INFO "Unpacking initramfs...\n");
 685
 686         err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
 687         if (err) {
 688 #ifdef CONFIG_BLK_DEV_RAM
 689                 populate_initrd_image(err);
 690 #else
 691                 printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 692 #endif
 693         }
 694
 695 done:
 696         /*
 697          * If the initrd region is overlapped with crashkernel reserved region,
 698          * free only memory that is not part of crashkernel region.
 699          */
 700         if (!do_retain_initrd && initrd_start && !kexec_free_initrd())
 701                 free_initrd_mem(initrd_start, initrd_end);
 702         initrd_start = 0;
 703         initrd_end = 0;
 704
 705         flush_delayed_fput();
 706 }
 707
 708 static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);
 709 static async_cookie_t initramfs_cookie;
 710
 711 void wait_for_initramfs(void)
 712 {
 713         if (!initramfs_cookie) {
 714                 /*
 715                  * Something before rootfs_initcall wants to access
 716                  * the filesystem/initramfs. Probably a bug. Make a
 717                  * note, avoid deadlocking the machine, and let the
 718                  * caller's access fail as it used to.
 719                  */
 720                 pr_warn_once("wait_for_initramfs() called before rootfs_initcalls\n");
 721                 return;
 722         }
 723         async_synchronize_cookie_domain(initramfs_cookie + 1, &initramfs_domain);
 724 }
 725 EXPORT_SYMBOL_GPL(wait_for_initramfs);
 726
 727 static int __init populate_rootfs(void)
 728 {
 729         initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL,
 730                                                  &initramfs_domain);
 731         usermodehelper_enable();
 732         if (!initramfs_async)
 733                 wait_for_initramfs();
 734         return 0;
 735 }
 736 rootfs_initcall(populate_rootfs);