init/initramfs.c

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