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