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