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 #include <linux/initramfs.h>
  24
  25 static ssize_t __init xwrite(int fd, const char *p, size_t count)
  26 {
  27         ssize_t out = 0;
  28
  29         /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
  30         while (count) {
  31                 ssize_t rv = sys_write(fd, p, count);
  32
  33                 if (rv < 0) {
  34                         if (rv == -EINTR || rv == -EAGAIN)
  35                                 continue;
  36                         return out ? out : rv;
  37                 } else if (rv == 0)
  38                         break;
  39
  40                 p += rv;
  41                 out += rv;
  42                 count -= rv;
  43         }
  44
  45         return out;
  46 }
  47
  48 static __initdata char *message;
  49 static void __init error(char *x)
  50 {
  51         if (!message)
  52                 message = x;
  53 }
  54
  55 /* link hash */
  56
  57 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  58
  59 static __initdata struct hash {
  60         int ino, minor, major;
  61         umode_t mode;
  62         struct hash *next;
  63         char name[N_ALIGN(PATH_MAX)];
  64 } *head[32];
  65
  66 static inline int hash(int major, int minor, int ino)
  67 {
  68         unsigned long tmp = ino + minor + (major << 3);
  69         tmp += tmp >> 5;
  70         return tmp & 31;
  71 }
  72
  73 static char __init *find_link(int major, int minor, int ino,
  74                               umode_t mode, char *name)
  75 {
  76         struct hash **p, *q;
  77         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  78                 if ((*p)->ino != ino)
  79                         continue;
  80                 if ((*p)->minor != minor)
  81                         continue;
  82                 if ((*p)->major != major)
  83                         continue;
  84                 if (((*p)->mode ^ mode) & S_IFMT)
  85                         continue;
  86                 return (*p)->name;
  87         }
  88         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  89         if (!q)
  90                 panic("can't allocate link hash entry");
  91         q->major = major;
  92         q->minor = minor;
  93         q->ino = ino;
  94         q->mode = mode;
  95         strcpy(q->name, name);
  96         q->next = NULL;
  97         *p = q;
  98         return NULL;
  99 }
 100
 101 static void __init free_hash(void)
 102 {
 103         struct hash **p, *q;
 104         for (p = head; p < head + 32; p++) {
 105                 while (*p) {
 106                         q = *p;
 107                         *p = q->next;
 108                         kfree(q);
 109                 }
 110         }
 111 }
 112
 113 static long __init do_utime(char *filename, time_t mtime)
 114 {
 115         struct timespec64 t[2];
 116
 117         t[0].tv_sec = mtime;
 118         t[0].tv_nsec = 0;
 119         t[1].tv_sec = mtime;
 120         t[1].tv_nsec = 0;
 121
 122         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
 123 }
 124
 125 static __initdata LIST_HEAD(dir_list);
 126 struct dir_entry {
 127         struct list_head list;
 128         char *name;
 129         time_t mtime;
 130 };
 131
 132 static void __init dir_add(const char *name, time_t mtime)
 133 {
 134         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 135         if (!de)
 136                 panic("can't allocate dir_entry buffer");
 137         INIT_LIST_HEAD(&de->list);
 138         de->name = kstrdup(name, GFP_KERNEL);
 139         de->mtime = mtime;
 140         list_add(&de->list, &dir_list);
 141 }
 142
 143 static void __init dir_utime(void)
 144 {
 145         struct dir_entry *de, *tmp;
 146         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 147                 list_del(&de->list);
 148                 do_utime(de->name, de->mtime);
 149                 kfree(de->name);
 150                 kfree(de);
 151         }
 152 }
 153
 154 static __initdata time_t mtime;
 155
 156 /* cpio header parsing */
 157
 158 static __initdata unsigned long ino, major, minor, nlink;
 159 static __initdata umode_t mode;
 160 static __initdata unsigned long body_len, name_len;
 161 static __initdata uid_t uid;
 162 static __initdata gid_t gid;
 163 static __initdata unsigned rdev;
 164
 165 static void __init parse_header(char *s)
 166 {
 167         unsigned long parsed[12];
 168         char buf[9];
 169         int i;
 170
 171         buf[8] = '\0';
 172         for (i = 0, s += 6; i < 12; i++, s += 8) {
 173                 memcpy(buf, s, 8);
 174                 parsed[i] = simple_strtoul(buf, NULL, 16);
 175         }
 176         ino = parsed[0];
 177         mode = parsed[1];
 178         uid = parsed[2];
 179         gid = parsed[3];
 180         nlink = parsed[4];
 181         mtime = parsed[5];
 182         body_len = parsed[6];
 183         major = parsed[7];
 184         minor = parsed[8];
 185         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 186         name_len = parsed[11];
 187 }
 188
 189 /* FSM */
 190
 191 static __initdata enum state {
 192         Start,
 193         Collect,
 194         GotHeader,
 195         SkipIt,
 196         GotName,
 197         CopyFile,
 198         GotSymlink,
 199         Reset
 200 } state, next_state;
 201
 202 static __initdata char *victim;
 203 static unsigned long byte_count __initdata;
 204 static __initdata loff_t this_header, next_header;
 205
 206 static inline void __init eat(unsigned n)
 207 {
 208         victim += n;
 209         this_header += n;
 210         byte_count -= n;
 211 }
 212
 213 static __initdata char *vcollected;
 214 static __initdata char *collected;
 215 static long remains __initdata;
 216 static __initdata char *collect;
 217
 218 static void __init read_into(char *buf, unsigned size, enum state next)
 219 {
 220         if (byte_count >= size) {
 221                 collected = victim;
 222                 eat(size);
 223                 state = next;
 224         } else {
 225                 collect = collected = buf;
 226                 remains = size;
 227                 next_state = next;
 228                 state = Collect;
 229         }
 230 }
 231
 232 static __initdata char *header_buf, *symlink_buf, *name_buf;
 233
 234 static int __init do_start(void)
 235 {
 236         read_into(header_buf, 110, GotHeader);
 237         return 0;
 238 }
 239
 240 static int __init do_collect(void)
 241 {
 242         unsigned long n = remains;
 243         if (byte_count < n)
 244                 n = byte_count;
 245         memcpy(collect, victim, n);
 246         eat(n);
 247         collect += n;
 248         if ((remains -= n) != 0)
 249                 return 1;
 250         state = next_state;
 251         return 0;
 252 }
 253
 254 static int __init do_header(void)
 255 {
 256         if (memcmp(collected, "070707", 6)==0) {
 257                 error("incorrect cpio method used: use -H newc option");
 258                 return 1;
 259         }
 260         if (memcmp(collected, "070701", 6)) {
 261                 error("no cpio magic");
 262                 return 1;
 263         }
 264         parse_header(collected);
 265         next_header = this_header + N_ALIGN(name_len) + body_len;
 266         next_header = (next_header + 3) & ~3;
 267         state = SkipIt;
 268         if (name_len <= 0 || name_len > PATH_MAX)
 269                 return 0;
 270         if (S_ISLNK(mode)) {
 271                 if (body_len > PATH_MAX)
 272                         return 0;
 273                 collect = collected = symlink_buf;
 274                 remains = N_ALIGN(name_len) + body_len;
 275                 next_state = GotSymlink;
 276                 state = Collect;
 277                 return 0;
 278         }
 279         if (S_ISREG(mode) || !body_len)
 280                 read_into(name_buf, N_ALIGN(name_len), GotName);
 281         return 0;
 282 }
 283
 284 static int __init do_skip(void)
 285 {
 286         if (this_header + byte_count < next_header) {
 287                 eat(byte_count);
 288                 return 1;
 289         } else {
 290                 eat(next_header - this_header);
 291                 state = next_state;
 292                 return 0;
 293         }
 294 }
 295
 296 static int __init do_reset(void)
 297 {
 298         while (byte_count && *victim == '\0')
 299                 eat(1);
 300         if (byte_count && (this_header & 3))
 301                 error("broken padding");
 302         return 1;
 303 }
 304
 305 static int __init maybe_link(void)
 306 {
 307         if (nlink >= 2) {
 308                 char *old = find_link(major, minor, ino, mode, collected);
 309                 if (old)
 310                         return (sys_link(old, collected) < 0) ? -1 : 1;
 311         }
 312         return 0;
 313 }
 314
 315 static void __init clean_path(char *path, umode_t fmode)
 316 {
 317         struct kstat st;
 318
 319         if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) {
 320                 if (S_ISDIR(st.mode))
 321                         sys_rmdir(path);
 322                 else
 323                         sys_unlink(path);
 324         }
 325 }
 326
 327 static __initdata int wfd;
 328
 329 static int __init do_name(void)
 330 {
 331         state = SkipIt;
 332         next_state = Reset;
 333         if (strcmp(collected, "TRAILER!!!") == 0) {
 334                 free_hash();
 335                 return 0;
 336         }
 337         clean_path(collected, mode);
 338         if (S_ISREG(mode)) {
 339                 int ml = maybe_link();
 340                 if (ml >= 0) {
 341                         int openflags = O_WRONLY|O_CREAT;
 342                         if (ml != 1)
 343                                 openflags |= O_TRUNC;
 344                         wfd = sys_open(collected, openflags, mode);
 345
 346                         if (wfd >= 0) {
 347                                 sys_fchown(wfd, uid, gid);
 348                                 sys_fchmod(wfd, mode);
 349                                 if (body_len)
 350                                         sys_ftruncate(wfd, body_len);
 351                                 vcollected = kstrdup(collected, GFP_KERNEL);
 352                                 state = CopyFile;
 353                         }
 354                 }
 355         } else if (S_ISDIR(mode)) {
 356                 sys_mkdir(collected, mode);
 357                 sys_chown(collected, uid, gid);
 358                 sys_chmod(collected, mode);
 359                 dir_add(collected, mtime);
 360         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 361                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 362                 if (maybe_link() == 0) {
 363                         sys_mknod(collected, mode, rdev);
 364                         sys_chown(collected, uid, gid);
 365                         sys_chmod(collected, mode);
 366                         do_utime(collected, mtime);
 367                 }
 368         }
 369         return 0;
 370 }
 371
 372 static int __init do_copy(void)
 373 {
 374         if (byte_count >= body_len) {
 375                 if (xwrite(wfd, victim, body_len) != body_len)
 376                         error("write error");
 377                 sys_close(wfd);
 378                 do_utime(vcollected, mtime);
 379                 kfree(vcollected);
 380                 eat(body_len);
 381                 state = SkipIt;
 382                 return 0;
 383         } else {
 384                 if (xwrite(wfd, victim, byte_count) != byte_count)
 385                         error("write error");
 386                 body_len -= byte_count;
 387                 eat(byte_count);
 388                 return 1;
 389         }
 390 }
 391
 392 static int __init do_symlink(void)
 393 {
 394         collected[N_ALIGN(name_len) + body_len] = '\0';
 395         clean_path(collected, 0);
 396         sys_symlink(collected + N_ALIGN(name_len), collected);
 397         sys_lchown(collected, uid, gid);
 398         do_utime(collected, mtime);
 399         state = SkipIt;
 400         next_state = Reset;
 401         return 0;
 402 }
 403
 404 static __initdata int (*actions[])(void) = {
 405         [Start]         = do_start,
 406         [Collect]       = do_collect,
 407         [GotHeader]     = do_header,
 408         [SkipIt]        = do_skip,
 409         [GotName]       = do_name,
 410         [CopyFile]      = do_copy,
 411         [GotSymlink]    = do_symlink,
 412         [Reset]         = do_reset,
 413 };
 414
 415 static long __init write_buffer(char *buf, unsigned long len)
 416 {
 417         byte_count = len;
 418         victim = buf;
 419
 420         while (!actions[state]())
 421                 ;
 422         return len - byte_count;
 423 }
 424
 425 static long __init flush_buffer(void *bufv, unsigned long len)
 426 {
 427         char *buf = (char *) bufv;
 428         long written;
 429         long origLen = len;
 430         if (message)
 431                 return -1;
 432         while ((written = write_buffer(buf, len)) < len && !message) {
 433                 char c = buf[written];
 434                 if (c == '0') {
 435                         buf += written;
 436                         len -= written;
 437                         state = Start;
 438                 } else if (c == 0) {
 439                         buf += written;
 440                         len -= written;
 441                         state = Reset;
 442                 } else
 443                         error("junk in compressed archive");
 444         }
 445         return origLen;
 446 }
 447
 448 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
 449
 450 #include <linux/decompress/generic.h>
 451
 452 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 453 {
 454         long written;
 455         decompress_fn decompress;
 456         const char *compress_name;
 457         static __initdata char msg_buf[64];
 458
 459         header_buf = kmalloc(110, GFP_KERNEL);
 460         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 461         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 462
 463         if (!header_buf || !symlink_buf || !name_buf)
 464                 panic("can't allocate buffers");
 465
 466         state = Start;
 467         this_header = 0;
 468         message = NULL;
 469         while (!message && len) {
 470                 loff_t saved_offset = this_header;
 471                 if (*buf == '0' && !(this_header & 3)) {
 472                         state = Start;
 473                         written = write_buffer(buf, len);
 474                         buf += written;
 475                         len -= written;
 476                         continue;
 477                 }
 478                 if (!*buf) {
 479                         buf++;
 480                         len--;
 481                         this_header++;
 482                         continue;
 483                 }
 484                 this_header = 0;
 485                 decompress = decompress_method(buf, len, &compress_name);
 486                 pr_debug("Detected %s compressed data\n", compress_name);
 487                 if (decompress) {
 488                         int res = decompress(buf, len, NULL, flush_buffer, NULL,
 489                                    &my_inptr, error);
 490                         if (res)
 491                                 error("decompressor failed");
 492                 } else if (compress_name) {
 493                         if (!message) {
 494                                 snprintf(msg_buf, sizeof msg_buf,
 495                                          "compression method %s not configured",
 496                                          compress_name);
 497                                 message = msg_buf;
 498                         }
 499                 } else
 500                         error("junk in compressed archive");
 501                 if (state != Reset)
 502                         error("junk in compressed archive");
 503                 this_header = saved_offset + my_inptr;
 504                 buf += my_inptr;
 505                 len -= my_inptr;
 506         }
 507         dir_utime();
 508         kfree(name_buf);
 509         kfree(symlink_buf);
 510         kfree(header_buf);
 511         return message;
 512 }
 513
 514 static int __initdata do_retain_initrd;
 515
 516 static int __init retain_initrd_param(char *str)
 517 {
 518         if (*str)
 519                 return 0;
 520         do_retain_initrd = 1;
 521         return 1;
 522 }
 523 __setup("retain_initrd", retain_initrd_param);
 524
 525 extern char __initramfs_start[];
 526 extern unsigned long __initramfs_size;
 527 #include <linux/initrd.h>
 528 #include <linux/kexec.h>
 529
 530 static void __init free_initrd(void)
 531 {
 532 #ifdef CONFIG_KEXEC_CORE
 533         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 534         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 535 #endif
 536         if (do_retain_initrd)
 537                 goto skip;
 538
 539 #ifdef CONFIG_KEXEC_CORE
 540         /*
 541          * If the initrd region is overlapped with crashkernel reserved region,
 542          * free only memory that is not part of crashkernel region.
 543          */
 544         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 545                 /*
 546                  * Initialize initrd memory region since the kexec boot does
 547                  * not do.
 548                  */
 549                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 550                 if (initrd_start < crashk_start)
 551                         free_initrd_mem(initrd_start, crashk_start);
 552                 if (initrd_end > crashk_end)
 553                         free_initrd_mem(crashk_end, initrd_end);
 554         } else
 555 #endif
 556                 free_initrd_mem(initrd_start, initrd_end);
 557 skip:
 558         initrd_start = 0;
 559         initrd_end = 0;
 560 }
 561
 562 #ifdef CONFIG_BLK_DEV_RAM
 563 #define BUF_SIZE 1024
 564 static void __init clean_rootfs(void)
 565 {
 566         int fd;
 567         void *buf;
 568         struct linux_dirent64 *dirp;
 569         int num;
 570
 571         fd = sys_open("/", O_RDONLY, 0);
 572         WARN_ON(fd < 0);
 573         if (fd < 0)
 574                 return;
 575         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 576         WARN_ON(!buf);
 577         if (!buf) {
 578                 sys_close(fd);
 579                 return;
 580         }
 581
 582         dirp = buf;
 583         num = sys_getdents64(fd, dirp, BUF_SIZE);
 584         while (num > 0) {
 585                 while (num > 0) {
 586                         struct kstat st;
 587                         int ret;
 588
 589                         ret = vfs_lstat(dirp->d_name, &st);
 590                         WARN_ON_ONCE(ret);
 591                         if (!ret) {
 592                                 if (S_ISDIR(st.mode))
 593                                         sys_rmdir(dirp->d_name);
 594                                 else
 595                                         sys_unlink(dirp->d_name);
 596                         }
 597
 598                         num -= dirp->d_reclen;
 599                         dirp = (void *)dirp + dirp->d_reclen;
 600                 }
 601                 dirp = buf;
 602                 memset(buf, 0, BUF_SIZE);
 603                 num = sys_getdents64(fd, dirp, BUF_SIZE);
 604         }
 605
 606         sys_close(fd);
 607         kfree(buf);
 608 }
 609 #endif
 610
 611 static int __initdata do_skip_initramfs;
 612
 613 static int __init skip_initramfs_param(char *str)
 614 {
 615         if (*str)
 616                 return 0;
 617         do_skip_initramfs = 1;
 618         return 1;
 619 }
 620 __setup("skip_initramfs", skip_initramfs_param);
 621
 622 static int __init populate_rootfs(void)
 623 {
 624         char *err;
 625
 626 //      if (do_skip_initramfs) {
 627 //              if (initrd_start)
 628 //                      free_initrd();
 629 //              return default_rootfs();
 630 //      }
 631
 632         /* Load the built in initramfs */
 633         err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 634         if (err)
 635                 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
 636         /* If available load the bootloader supplied initrd */
 637         if (initrd_start && !IS_ENABLED(CONFIG_INITRAMFS_FORCE)) {
 638 #ifdef CONFIG_BLK_DEV_RAM
 639                 int fd;
 640                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 641                 err = unpack_to_rootfs((char *)initrd_start,
 642                         initrd_end - initrd_start);
 643                 if (!err) {
 644                         free_initrd();
 645                         goto done;
 646                 } else {
 647                         clean_rootfs();
 648                         unpack_to_rootfs(__initramfs_start, __initramfs_size);
 649                 }
 650                 printk(KERN_INFO "rootfs image is not initramfs (%s)"
 651                                 "; looks like an initrd\n", err);
 652                 fd = sys_open("/initrd.image",
 653                               O_WRONLY|O_CREAT, 0700);
 654                 if (fd >= 0) {
 655                         ssize_t written = xwrite(fd, (char *)initrd_start,
 656                                                 initrd_end - initrd_start);
 657
 658                         if (written != initrd_end - initrd_start)
 659                                 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 660                                        written, initrd_end - initrd_start);
 661
 662                         sys_close(fd);
 663                         free_initrd();
 664                 }
 665         done:
 666                 /* empty statement */;
 667 #else
 668                 printk(KERN_INFO "Unpacking initramfs...\n");
 669                 err = unpack_to_rootfs((char *)initrd_start,
 670                         initrd_end - initrd_start);
 671                 if (err)
 672                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 673                 free_initrd();
 674 #endif
 675         }
 676         flush_delayed_fput();
 677         /*
 678          * Try loading default modules from initramfs.  This gives
 679          * us a chance to load before device_initcalls.
 680          */
 681         load_default_modules();
 682
 683         return 0;
 684 }
 685 rootfs_initcall(populate_rootfs);