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1// SPDX-License-Identifier: GPL-2.0
2/****************************************************************************/
3/*
4 * linux/fs/binfmt_flat.c
5 *
6 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
7 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
8 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
9 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
10 * based heavily on:
11 *
12 * linux/fs/binfmt_aout.c:
13 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
14 * linux/fs/binfmt_flat.c for 2.0 kernel
15 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
16 * JAN/99 -- coded full program relocation (gerg@snapgear.com)
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/kernel.h>
22#include <linux/sched.h>
23#include <linux/sched/task_stack.h>
24#include <linux/mm.h>
25#include <linux/mman.h>
26#include <linux/errno.h>
27#include <linux/signal.h>
28#include <linux/string.h>
29#include <linux/fs.h>
30#include <linux/file.h>
31#include <linux/ptrace.h>
32#include <linux/user.h>
33#include <linux/slab.h>
34#include <linux/binfmts.h>
35#include <linux/personality.h>
36#include <linux/init.h>
37#include <linux/flat.h>
38#include <linux/uaccess.h>
39#include <linux/vmalloc.h>
40
41#include <asm/byteorder.h>
42#include <asm/unaligned.h>
43#include <asm/cacheflush.h>
44#include <asm/page.h>
45#include <asm/flat.h>
46
47#ifndef flat_get_relocate_addr
48#define flat_get_relocate_addr(rel) (rel)
49#endif
50
51/****************************************************************************/
52
53/*
54 * User data (data section and bss) needs to be aligned.
55 * We pick 0x20 here because it is the max value elf2flt has always
56 * used in producing FLAT files, and because it seems to be large
57 * enough to make all the gcc alignment related tests happy.
58 */
59#define FLAT_DATA_ALIGN (0x20)
60
61/*
62 * User data (stack) also needs to be aligned.
63 * Here we can be a bit looser than the data sections since this
64 * needs to only meet arch ABI requirements.
65 */
66#define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
67
68#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
69#define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
70
71#define MAX_SHARED_LIBS (1)
72
73#ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET
74#define DATA_START_OFFSET_WORDS (0)
75#else
76#define DATA_START_OFFSET_WORDS (MAX_SHARED_LIBS)
77#endif
78
79struct lib_info {
80 struct {
81 unsigned long start_code; /* Start of text segment */
82 unsigned long start_data; /* Start of data segment */
83 unsigned long start_brk; /* End of data segment */
84 unsigned long text_len; /* Length of text segment */
85 unsigned long entry; /* Start address for this module */
86 unsigned long build_date; /* When this one was compiled */
87 bool loaded; /* Has this library been loaded? */
88 } lib_list[MAX_SHARED_LIBS];
89};
90
91static int load_flat_binary(struct linux_binprm *);
92
93static struct linux_binfmt flat_format = {
94 .module = THIS_MODULE,
95 .load_binary = load_flat_binary,
96};
97
98
99/****************************************************************************/
100/*
101 * create_flat_tables() parses the env- and arg-strings in new user
102 * memory and creates the pointer tables from them, and puts their
103 * addresses on the "stack", recording the new stack pointer value.
104 */
105
106static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
107{
108 char __user *p;
109 unsigned long __user *sp;
110 long i, len;
111
112 p = (char __user *)arg_start;
113 sp = (unsigned long __user *)current->mm->start_stack;
114
115 sp -= bprm->envc + 1;
116 sp -= bprm->argc + 1;
117 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))
118 sp -= 2; /* argvp + envp */
119 sp -= 1; /* &argc */
120
121 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
122 sp = (unsigned long __user *)current->mm->start_stack;
123
124 if (put_user(bprm->argc, sp++))
125 return -EFAULT;
126 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
127 unsigned long argv, envp;
128 argv = (unsigned long)(sp + 2);
129 envp = (unsigned long)(sp + 2 + bprm->argc + 1);
130 if (put_user(argv, sp++) || put_user(envp, sp++))
131 return -EFAULT;
132 }
133
134 current->mm->arg_start = (unsigned long)p;
135 for (i = bprm->argc; i > 0; i--) {
136 if (put_user((unsigned long)p, sp++))
137 return -EFAULT;
138 len = strnlen_user(p, MAX_ARG_STRLEN);
139 if (!len || len > MAX_ARG_STRLEN)
140 return -EINVAL;
141 p += len;
142 }
143 if (put_user(0, sp++))
144 return -EFAULT;
145 current->mm->arg_end = (unsigned long)p;
146
147 current->mm->env_start = (unsigned long) p;
148 for (i = bprm->envc; i > 0; i--) {
149 if (put_user((unsigned long)p, sp++))
150 return -EFAULT;
151 len = strnlen_user(p, MAX_ARG_STRLEN);
152 if (!len || len > MAX_ARG_STRLEN)
153 return -EINVAL;
154 p += len;
155 }
156 if (put_user(0, sp++))
157 return -EFAULT;
158 current->mm->env_end = (unsigned long)p;
159
160 return 0;
161}
162
163/****************************************************************************/
164
165#ifdef CONFIG_BINFMT_ZFLAT
166
167#include <linux/zlib.h>
168
169#define LBUFSIZE 4000
170
171/* gzip flag byte */
172#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
173#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
174#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
175#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
176#define COMMENT 0x10 /* bit 4 set: file comment present */
177#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
178#define RESERVED 0xC0 /* bit 6,7: reserved */
179
180static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
181 long len, int fd)
182{
183 unsigned char *buf;
184 z_stream strm;
185 int ret, retval;
186
187 pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
188
189 memset(&strm, 0, sizeof(strm));
190 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
191 if (!strm.workspace)
192 return -ENOMEM;
193
194 buf = kmalloc(LBUFSIZE, GFP_KERNEL);
195 if (!buf) {
196 retval = -ENOMEM;
197 goto out_free;
198 }
199
200 /* Read in first chunk of data and parse gzip header. */
201 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
202
203 strm.next_in = buf;
204 strm.avail_in = ret;
205 strm.total_in = 0;
206
207 retval = -ENOEXEC;
208
209 /* Check minimum size -- gzip header */
210 if (ret < 10) {
211 pr_debug("file too small?\n");
212 goto out_free_buf;
213 }
214
215 /* Check gzip magic number */
216 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
217 pr_debug("unknown compression magic?\n");
218 goto out_free_buf;
219 }
220
221 /* Check gzip method */
222 if (buf[2] != 8) {
223 pr_debug("unknown compression method?\n");
224 goto out_free_buf;
225 }
226 /* Check gzip flags */
227 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
228 (buf[3] & RESERVED)) {
229 pr_debug("unknown flags?\n");
230 goto out_free_buf;
231 }
232
233 ret = 10;
234 if (buf[3] & EXTRA_FIELD) {
235 ret += 2 + buf[10] + (buf[11] << 8);
236 if (unlikely(ret >= LBUFSIZE)) {
237 pr_debug("buffer overflow (EXTRA)?\n");
238 goto out_free_buf;
239 }
240 }
241 if (buf[3] & ORIG_NAME) {
242 while (ret < LBUFSIZE && buf[ret++] != 0)
243 ;
244 if (unlikely(ret == LBUFSIZE)) {
245 pr_debug("buffer overflow (ORIG_NAME)?\n");
246 goto out_free_buf;
247 }
248 }
249 if (buf[3] & COMMENT) {
250 while (ret < LBUFSIZE && buf[ret++] != 0)
251 ;
252 if (unlikely(ret == LBUFSIZE)) {
253 pr_debug("buffer overflow (COMMENT)?\n");
254 goto out_free_buf;
255 }
256 }
257
258 strm.next_in += ret;
259 strm.avail_in -= ret;
260
261 strm.next_out = dst;
262 strm.avail_out = len;
263 strm.total_out = 0;
264
265 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
266 pr_debug("zlib init failed?\n");
267 goto out_free_buf;
268 }
269
270 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
271 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
272 if (ret <= 0)
273 break;
274 len -= ret;
275
276 strm.next_in = buf;
277 strm.avail_in = ret;
278 strm.total_in = 0;
279 }
280
281 if (ret < 0) {
282 pr_debug("decompression failed (%d), %s\n",
283 ret, strm.msg);
284 goto out_zlib;
285 }
286
287 retval = 0;
288out_zlib:
289 zlib_inflateEnd(&strm);
290out_free_buf:
291 kfree(buf);
292out_free:
293 kfree(strm.workspace);
294 return retval;
295}
296
297#endif /* CONFIG_BINFMT_ZFLAT */
298
299/****************************************************************************/
300
301static unsigned long
302calc_reloc(unsigned long r, struct lib_info *p)
303{
304 unsigned long addr;
305 unsigned long start_brk;
306 unsigned long start_data;
307 unsigned long text_len;
308 unsigned long start_code;
309
310 start_brk = p->lib_list[0].start_brk;
311 start_data = p->lib_list[0].start_data;
312 start_code = p->lib_list[0].start_code;
313 text_len = p->lib_list[0].text_len;
314
315 if (r > start_brk - start_data + text_len) {
316 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
317 r, start_brk-start_data+text_len, text_len);
318 goto failed;
319 }
320
321 if (r < text_len) /* In text segment */
322 addr = r + start_code;
323 else /* In data segment */
324 addr = r - text_len + start_data;
325
326 /* Range checked already above so doing the range tests is redundant...*/
327 return addr;
328
329failed:
330 pr_cont(", killing %s!\n", current->comm);
331 send_sig(SIGSEGV, current, 0);
332
333 return RELOC_FAILED;
334}
335
336/****************************************************************************/
337
338#ifdef CONFIG_BINFMT_FLAT_OLD
339static void old_reloc(unsigned long rl)
340{
341 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
342 flat_v2_reloc_t r;
343 unsigned long __user *ptr;
344 unsigned long val;
345
346 r.value = rl;
347#if defined(CONFIG_COLDFIRE)
348 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
349#else
350 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
351#endif
352 get_user(val, ptr);
353
354 pr_debug("Relocation of variable at DATASEG+%x "
355 "(address %p, currently %lx) into segment %s\n",
356 r.reloc.offset, ptr, val, segment[r.reloc.type]);
357
358 switch (r.reloc.type) {
359 case OLD_FLAT_RELOC_TYPE_TEXT:
360 val += current->mm->start_code;
361 break;
362 case OLD_FLAT_RELOC_TYPE_DATA:
363 val += current->mm->start_data;
364 break;
365 case OLD_FLAT_RELOC_TYPE_BSS:
366 val += current->mm->end_data;
367 break;
368 default:
369 pr_err("Unknown relocation type=%x\n", r.reloc.type);
370 break;
371 }
372 put_user(val, ptr);
373
374 pr_debug("Relocation became %lx\n", val);
375}
376#endif /* CONFIG_BINFMT_FLAT_OLD */
377
378/****************************************************************************/
379
380static inline u32 __user *skip_got_header(u32 __user *rp)
381{
382 if (IS_ENABLED(CONFIG_RISCV)) {
383 /*
384 * RISC-V has a 16 byte GOT PLT header for elf64-riscv
385 * and 8 byte GOT PLT header for elf32-riscv.
386 * Skip the whole GOT PLT header, since it is reserved
387 * for the dynamic linker (ld.so).
388 */
389 u32 rp_val0, rp_val1;
390
391 if (get_user(rp_val0, rp))
392 return rp;
393 if (get_user(rp_val1, rp + 1))
394 return rp;
395
396 if (rp_val0 == 0xffffffff && rp_val1 == 0xffffffff)
397 rp += 4;
398 else if (rp_val0 == 0xffffffff)
399 rp += 2;
400 }
401 return rp;
402}
403
404static int load_flat_file(struct linux_binprm *bprm,
405 struct lib_info *libinfo, unsigned long *extra_stack)
406{
407 struct flat_hdr *hdr;
408 unsigned long textpos, datapos, realdatastart;
409 u32 text_len, data_len, bss_len, stack_len, full_data, flags;
410 unsigned long len, memp, memp_size, extra, rlim;
411 __be32 __user *reloc;
412 u32 __user *rp;
413 int i, rev, relocs;
414 loff_t fpos;
415 unsigned long start_code, end_code;
416 ssize_t result;
417 int ret;
418
419 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
420
421 text_len = ntohl(hdr->data_start);
422 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
423 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
424 stack_len = ntohl(hdr->stack_size);
425 if (extra_stack) {
426 stack_len += *extra_stack;
427 *extra_stack = stack_len;
428 }
429 relocs = ntohl(hdr->reloc_count);
430 flags = ntohl(hdr->flags);
431 rev = ntohl(hdr->rev);
432 full_data = data_len + relocs * sizeof(unsigned long);
433
434 if (strncmp(hdr->magic, "bFLT", 4)) {
435 /*
436 * Previously, here was a printk to tell people
437 * "BINFMT_FLAT: bad header magic".
438 * But for the kernel which also use ELF FD-PIC format, this
439 * error message is confusing.
440 * because a lot of people do not manage to produce good
441 */
442 ret = -ENOEXEC;
443 goto err;
444 }
445
446 if (flags & FLAT_FLAG_KTRACE)
447 pr_info("Loading file: %s\n", bprm->filename);
448
449#ifdef CONFIG_BINFMT_FLAT_OLD
450 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
451 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
452 rev, FLAT_VERSION, OLD_FLAT_VERSION);
453 ret = -ENOEXEC;
454 goto err;
455 }
456
457 /*
458 * fix up the flags for the older format, there were all kinds
459 * of endian hacks, this only works for the simple cases
460 */
461 if (rev == OLD_FLAT_VERSION &&
462 (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
463 flags = FLAT_FLAG_RAM;
464
465#else /* CONFIG_BINFMT_FLAT_OLD */
466 if (rev != FLAT_VERSION) {
467 pr_err("bad flat file version 0x%x (supported 0x%lx)\n",
468 rev, FLAT_VERSION);
469 ret = -ENOEXEC;
470 goto err;
471 }
472#endif /* !CONFIG_BINFMT_FLAT_OLD */
473
474 /*
475 * Make sure the header params are sane.
476 * 28 bits (256 MB) is way more than reasonable in this case.
477 * If some top bits are set we have probable binary corruption.
478 */
479 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
480 pr_err("bad header\n");
481 ret = -ENOEXEC;
482 goto err;
483 }
484
485#ifndef CONFIG_BINFMT_ZFLAT
486 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
487 pr_err("Support for ZFLAT executables is not enabled.\n");
488 ret = -ENOEXEC;
489 goto err;
490 }
491#endif
492
493 /*
494 * Check initial limits. This avoids letting people circumvent
495 * size limits imposed on them by creating programs with large
496 * arrays in the data or bss.
497 */
498 rlim = rlimit(RLIMIT_DATA);
499 if (rlim >= RLIM_INFINITY)
500 rlim = ~0;
501 if (data_len + bss_len > rlim) {
502 ret = -ENOMEM;
503 goto err;
504 }
505
506 /* Flush all traces of the currently running executable */
507 ret = begin_new_exec(bprm);
508 if (ret)
509 goto err;
510
511 /* OK, This is the point of no return */
512 set_personality(PER_LINUX_32BIT);
513 setup_new_exec(bprm);
514
515 /*
516 * calculate the extra space we need to map in
517 */
518 extra = max_t(unsigned long, bss_len + stack_len,
519 relocs * sizeof(unsigned long));
520
521 /*
522 * there are a couple of cases here, the separate code/data
523 * case, and then the fully copied to RAM case which lumps
524 * it all together.
525 */
526 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
527 /*
528 * this should give us a ROM ptr, but if it doesn't we don't
529 * really care
530 */
531 pr_debug("ROM mapping of file (we hope)\n");
532
533 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
534 MAP_PRIVATE, 0);
535 if (!textpos || IS_ERR_VALUE(textpos)) {
536 ret = textpos;
537 if (!textpos)
538 ret = -ENOMEM;
539 pr_err("Unable to mmap process text, errno %d\n", ret);
540 goto err;
541 }
542
543 len = data_len + extra +
544 DATA_START_OFFSET_WORDS * sizeof(unsigned long);
545 len = PAGE_ALIGN(len);
546 realdatastart = vm_mmap(NULL, 0, len,
547 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
548
549 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
550 ret = realdatastart;
551 if (!realdatastart)
552 ret = -ENOMEM;
553 pr_err("Unable to allocate RAM for process data, "
554 "errno %d\n", ret);
555 vm_munmap(textpos, text_len);
556 goto err;
557 }
558 datapos = ALIGN(realdatastart +
559 DATA_START_OFFSET_WORDS * sizeof(unsigned long),
560 FLAT_DATA_ALIGN);
561
562 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
563 data_len + bss_len + stack_len, datapos);
564
565 fpos = ntohl(hdr->data_start);
566#ifdef CONFIG_BINFMT_ZFLAT
567 if (flags & FLAT_FLAG_GZDATA) {
568 result = decompress_exec(bprm, fpos, (char *)datapos,
569 full_data, 0);
570 } else
571#endif
572 {
573 result = read_code(bprm->file, datapos, fpos,
574 full_data);
575 }
576 if (IS_ERR_VALUE(result)) {
577 ret = result;
578 pr_err("Unable to read data+bss, errno %d\n", ret);
579 vm_munmap(textpos, text_len);
580 vm_munmap(realdatastart, len);
581 goto err;
582 }
583
584 reloc = (__be32 __user *)
585 (datapos + (ntohl(hdr->reloc_start) - text_len));
586 memp = realdatastart;
587 memp_size = len;
588 } else {
589
590 len = text_len + data_len + extra +
591 DATA_START_OFFSET_WORDS * sizeof(u32);
592 len = PAGE_ALIGN(len);
593 textpos = vm_mmap(NULL, 0, len,
594 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
595
596 if (!textpos || IS_ERR_VALUE(textpos)) {
597 ret = textpos;
598 if (!textpos)
599 ret = -ENOMEM;
600 pr_err("Unable to allocate RAM for process text/data, "
601 "errno %d\n", ret);
602 goto err;
603 }
604
605 realdatastart = textpos + ntohl(hdr->data_start);
606 datapos = ALIGN(realdatastart +
607 DATA_START_OFFSET_WORDS * sizeof(u32),
608 FLAT_DATA_ALIGN);
609
610 reloc = (__be32 __user *)
611 (datapos + (ntohl(hdr->reloc_start) - text_len));
612 memp = textpos;
613 memp_size = len;
614#ifdef CONFIG_BINFMT_ZFLAT
615 /*
616 * load it all in and treat it like a RAM load from now on
617 */
618 if (flags & FLAT_FLAG_GZIP) {
619#ifndef CONFIG_MMU
620 result = decompress_exec(bprm, sizeof(struct flat_hdr),
621 (((char *)textpos) + sizeof(struct flat_hdr)),
622 (text_len + full_data
623 - sizeof(struct flat_hdr)),
624 0);
625 memmove((void *) datapos, (void *) realdatastart,
626 full_data);
627#else
628 /*
629 * This is used on MMU systems mainly for testing.
630 * Let's use a kernel buffer to simplify things.
631 */
632 long unz_text_len = text_len - sizeof(struct flat_hdr);
633 long unz_len = unz_text_len + full_data;
634 char *unz_data = vmalloc(unz_len);
635 if (!unz_data) {
636 result = -ENOMEM;
637 } else {
638 result = decompress_exec(bprm, sizeof(struct flat_hdr),
639 unz_data, unz_len, 0);
640 if (result == 0 &&
641 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
642 unz_data, unz_text_len) ||
643 copy_to_user((void __user *)datapos,
644 unz_data + unz_text_len, full_data)))
645 result = -EFAULT;
646 vfree(unz_data);
647 }
648#endif
649 } else if (flags & FLAT_FLAG_GZDATA) {
650 result = read_code(bprm->file, textpos, 0, text_len);
651 if (!IS_ERR_VALUE(result)) {
652#ifndef CONFIG_MMU
653 result = decompress_exec(bprm, text_len, (char *) datapos,
654 full_data, 0);
655#else
656 char *unz_data = vmalloc(full_data);
657 if (!unz_data) {
658 result = -ENOMEM;
659 } else {
660 result = decompress_exec(bprm, text_len,
661 unz_data, full_data, 0);
662 if (result == 0 &&
663 copy_to_user((void __user *)datapos,
664 unz_data, full_data))
665 result = -EFAULT;
666 vfree(unz_data);
667 }
668#endif
669 }
670 } else
671#endif /* CONFIG_BINFMT_ZFLAT */
672 {
673 result = read_code(bprm->file, textpos, 0, text_len);
674 if (!IS_ERR_VALUE(result))
675 result = read_code(bprm->file, datapos,
676 ntohl(hdr->data_start),
677 full_data);
678 }
679 if (IS_ERR_VALUE(result)) {
680 ret = result;
681 pr_err("Unable to read code+data+bss, errno %d\n", ret);
682 vm_munmap(textpos, text_len + data_len + extra +
683 DATA_START_OFFSET_WORDS * sizeof(u32));
684 goto err;
685 }
686 }
687
688 start_code = textpos + sizeof(struct flat_hdr);
689 end_code = textpos + text_len;
690 text_len -= sizeof(struct flat_hdr); /* the real code len */
691
692 /* The main program needs a little extra setup in the task structure */
693 current->mm->start_code = start_code;
694 current->mm->end_code = end_code;
695 current->mm->start_data = datapos;
696 current->mm->end_data = datapos + data_len;
697 /*
698 * set up the brk stuff, uses any slack left in data/bss/stack
699 * allocation. We put the brk after the bss (between the bss
700 * and stack) like other platforms.
701 * Userspace code relies on the stack pointer starting out at
702 * an address right at the end of a page.
703 */
704 current->mm->start_brk = datapos + data_len + bss_len;
705 current->mm->brk = (current->mm->start_brk + 3) & ~3;
706#ifndef CONFIG_MMU
707 current->mm->context.end_brk = memp + memp_size - stack_len;
708#endif
709
710 if (flags & FLAT_FLAG_KTRACE) {
711 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
712 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
713 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
714 "Load", bprm->filename,
715 start_code, end_code, datapos, datapos + data_len,
716 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
717 }
718
719 /* Store the current module values into the global library structure */
720 libinfo->lib_list[0].start_code = start_code;
721 libinfo->lib_list[0].start_data = datapos;
722 libinfo->lib_list[0].start_brk = datapos + data_len + bss_len;
723 libinfo->lib_list[0].text_len = text_len;
724 libinfo->lib_list[0].loaded = 1;
725 libinfo->lib_list[0].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
726 libinfo->lib_list[0].build_date = ntohl(hdr->build_date);
727
728 /*
729 * We just load the allocations into some temporary memory to
730 * help simplify all this mumbo jumbo
731 *
732 * We've got two different sections of relocation entries.
733 * The first is the GOT which resides at the beginning of the data segment
734 * and is terminated with a -1. This one can be relocated in place.
735 * The second is the extra relocation entries tacked after the image's
736 * data segment. These require a little more processing as the entry is
737 * really an offset into the image which contains an offset into the
738 * image.
739 */
740 if (flags & FLAT_FLAG_GOTPIC) {
741 rp = skip_got_header((u32 __user *) datapos);
742 for (; ; rp++) {
743 u32 addr, rp_val;
744 if (get_user(rp_val, rp))
745 return -EFAULT;
746 if (rp_val == 0xffffffff)
747 break;
748 if (rp_val) {
749 addr = calc_reloc(rp_val, libinfo);
750 if (addr == RELOC_FAILED) {
751 ret = -ENOEXEC;
752 goto err;
753 }
754 if (put_user(addr, rp))
755 return -EFAULT;
756 }
757 }
758 }
759
760 /*
761 * Now run through the relocation entries.
762 * We've got to be careful here as C++ produces relocatable zero
763 * entries in the constructor and destructor tables which are then
764 * tested for being not zero (which will always occur unless we're
765 * based from address zero). This causes an endless loop as __start
766 * is at zero. The solution used is to not relocate zero addresses.
767 * This has the negative side effect of not allowing a global data
768 * reference to be statically initialised to _stext (I've moved
769 * __start to address 4 so that is okay).
770 */
771 if (rev > OLD_FLAT_VERSION) {
772 for (i = 0; i < relocs; i++) {
773 u32 addr, relval;
774 __be32 tmp;
775
776 /*
777 * Get the address of the pointer to be
778 * relocated (of course, the address has to be
779 * relocated first).
780 */
781 if (get_user(tmp, reloc + i))
782 return -EFAULT;
783 relval = ntohl(tmp);
784 addr = flat_get_relocate_addr(relval);
785 rp = (u32 __user *)calc_reloc(addr, libinfo);
786 if (rp == (u32 __user *)RELOC_FAILED) {
787 ret = -ENOEXEC;
788 goto err;
789 }
790
791 /* Get the pointer's value. */
792 ret = flat_get_addr_from_rp(rp, relval, flags, &addr);
793 if (unlikely(ret))
794 goto err;
795
796 if (addr != 0) {
797 /*
798 * Do the relocation. PIC relocs in the data section are
799 * already in target order
800 */
801 if ((flags & FLAT_FLAG_GOTPIC) == 0) {
802 /*
803 * Meh, the same value can have a different
804 * byte order based on a flag..
805 */
806 addr = ntohl((__force __be32)addr);
807 }
808 addr = calc_reloc(addr, libinfo);
809 if (addr == RELOC_FAILED) {
810 ret = -ENOEXEC;
811 goto err;
812 }
813
814 /* Write back the relocated pointer. */
815 ret = flat_put_addr_at_rp(rp, addr, relval);
816 if (unlikely(ret))
817 goto err;
818 }
819 }
820#ifdef CONFIG_BINFMT_FLAT_OLD
821 } else {
822 for (i = 0; i < relocs; i++) {
823 __be32 relval;
824 if (get_user(relval, reloc + i))
825 return -EFAULT;
826 old_reloc(ntohl(relval));
827 }
828#endif /* CONFIG_BINFMT_FLAT_OLD */
829 }
830
831 flush_icache_user_range(start_code, end_code);
832
833 /* zero the BSS, BRK and stack areas */
834 if (clear_user((void __user *)(datapos + data_len), bss_len +
835 (memp + memp_size - stack_len - /* end brk */
836 libinfo->lib_list[0].start_brk) + /* start brk */
837 stack_len))
838 return -EFAULT;
839
840 return 0;
841err:
842 return ret;
843}
844
845
846/****************************************************************************/
847
848/*
849 * These are the functions used to load flat style executables and shared
850 * libraries. There is no binary dependent code anywhere else.
851 */
852
853static int load_flat_binary(struct linux_binprm *bprm)
854{
855 struct lib_info libinfo;
856 struct pt_regs *regs = current_pt_regs();
857 unsigned long stack_len = 0;
858 unsigned long start_addr;
859 int res;
860 int i, j;
861
862 memset(&libinfo, 0, sizeof(libinfo));
863
864 /*
865 * We have to add the size of our arguments to our stack size
866 * otherwise it's too easy for users to create stack overflows
867 * by passing in a huge argument list. And yes, we have to be
868 * pedantic and include space for the argv/envp array as it may have
869 * a lot of entries.
870 */
871#ifndef CONFIG_MMU
872 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
873#endif
874 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
875 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
876 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
877
878 res = load_flat_file(bprm, &libinfo, &stack_len);
879 if (res < 0)
880 return res;
881
882 /* Update data segment pointers for all libraries */
883 for (i = 0; i < MAX_SHARED_LIBS; i++) {
884 if (!libinfo.lib_list[i].loaded)
885 continue;
886 for (j = 0; j < MAX_SHARED_LIBS; j++) {
887 unsigned long val = libinfo.lib_list[j].loaded ?
888 libinfo.lib_list[j].start_data : UNLOADED_LIB;
889 unsigned long __user *p = (unsigned long __user *)
890 libinfo.lib_list[i].start_data;
891 p -= j + 1;
892 if (put_user(val, p))
893 return -EFAULT;
894 }
895 }
896
897 set_binfmt(&flat_format);
898
899#ifdef CONFIG_MMU
900 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
901 if (!res)
902 res = create_flat_tables(bprm, bprm->p);
903#else
904 /* Stash our initial stack pointer into the mm structure */
905 current->mm->start_stack =
906 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
907 pr_debug("sp=%lx\n", current->mm->start_stack);
908
909 /* copy the arg pages onto the stack */
910 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack);
911 if (!res)
912 res = create_flat_tables(bprm, current->mm->start_stack);
913#endif
914 if (res)
915 return res;
916
917 /* Fake some return addresses to ensure the call chain will
918 * initialise library in order for us. We are required to call
919 * lib 1 first, then 2, ... and finally the main program (id 0).
920 */
921 start_addr = libinfo.lib_list[0].entry;
922
923#ifdef FLAT_PLAT_INIT
924 FLAT_PLAT_INIT(regs);
925#endif
926
927 finalize_exec(bprm);
928 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
929 regs, start_addr, current->mm->start_stack);
930 start_thread(regs, start_addr, current->mm->start_stack);
931
932 return 0;
933}
934
935/****************************************************************************/
936
937static int __init init_flat_binfmt(void)
938{
939 register_binfmt(&flat_format);
940 return 0;
941}
942core_initcall(init_flat_binfmt);
943
944/****************************************************************************/
1// SPDX-License-Identifier: GPL-2.0
2/****************************************************************************/
3/*
4 * linux/fs/binfmt_flat.c
5 *
6 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
7 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
8 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
9 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
10 * based heavily on:
11 *
12 * linux/fs/binfmt_aout.c:
13 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
14 * linux/fs/binfmt_flat.c for 2.0 kernel
15 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
16 * JAN/99 -- coded full program relocation (gerg@snapgear.com)
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/kernel.h>
22#include <linux/sched.h>
23#include <linux/sched/task_stack.h>
24#include <linux/mm.h>
25#include <linux/mman.h>
26#include <linux/errno.h>
27#include <linux/signal.h>
28#include <linux/string.h>
29#include <linux/fs.h>
30#include <linux/file.h>
31#include <linux/ptrace.h>
32#include <linux/user.h>
33#include <linux/slab.h>
34#include <linux/binfmts.h>
35#include <linux/personality.h>
36#include <linux/init.h>
37#include <linux/flat.h>
38#include <linux/uaccess.h>
39#include <linux/vmalloc.h>
40
41#include <asm/byteorder.h>
42#include <asm/unaligned.h>
43#include <asm/cacheflush.h>
44#include <asm/page.h>
45#include <asm/flat.h>
46
47#ifndef flat_get_relocate_addr
48#define flat_get_relocate_addr(rel) (rel)
49#endif
50
51/****************************************************************************/
52
53/*
54 * User data (data section and bss) needs to be aligned.
55 * We pick 0x20 here because it is the max value elf2flt has always
56 * used in producing FLAT files, and because it seems to be large
57 * enough to make all the gcc alignment related tests happy.
58 */
59#define FLAT_DATA_ALIGN (0x20)
60
61/*
62 * User data (stack) also needs to be aligned.
63 * Here we can be a bit looser than the data sections since this
64 * needs to only meet arch ABI requirements.
65 */
66#define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
67
68#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
69#define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
70
71#ifdef CONFIG_BINFMT_SHARED_FLAT
72#define MAX_SHARED_LIBS (4)
73#else
74#define MAX_SHARED_LIBS (1)
75#endif
76
77#ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET
78#define DATA_START_OFFSET_WORDS (0)
79#else
80#define DATA_START_OFFSET_WORDS (MAX_SHARED_LIBS)
81#endif
82
83struct lib_info {
84 struct {
85 unsigned long start_code; /* Start of text segment */
86 unsigned long start_data; /* Start of data segment */
87 unsigned long start_brk; /* End of data segment */
88 unsigned long text_len; /* Length of text segment */
89 unsigned long entry; /* Start address for this module */
90 unsigned long build_date; /* When this one was compiled */
91 bool loaded; /* Has this library been loaded? */
92 } lib_list[MAX_SHARED_LIBS];
93};
94
95#ifdef CONFIG_BINFMT_SHARED_FLAT
96static int load_flat_shared_library(int id, struct lib_info *p);
97#endif
98
99static int load_flat_binary(struct linux_binprm *);
100static int flat_core_dump(struct coredump_params *cprm);
101
102static struct linux_binfmt flat_format = {
103 .module = THIS_MODULE,
104 .load_binary = load_flat_binary,
105 .core_dump = flat_core_dump,
106 .min_coredump = PAGE_SIZE
107};
108
109/****************************************************************************/
110/*
111 * Routine writes a core dump image in the current directory.
112 * Currently only a stub-function.
113 */
114
115static int flat_core_dump(struct coredump_params *cprm)
116{
117 pr_warn("Process %s:%d received signr %d and should have core dumped\n",
118 current->comm, current->pid, cprm->siginfo->si_signo);
119 return 1;
120}
121
122/****************************************************************************/
123/*
124 * create_flat_tables() parses the env- and arg-strings in new user
125 * memory and creates the pointer tables from them, and puts their
126 * addresses on the "stack", recording the new stack pointer value.
127 */
128
129static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
130{
131 char __user *p;
132 unsigned long __user *sp;
133 long i, len;
134
135 p = (char __user *)arg_start;
136 sp = (unsigned long __user *)current->mm->start_stack;
137
138 sp -= bprm->envc + 1;
139 sp -= bprm->argc + 1;
140 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))
141 sp -= 2; /* argvp + envp */
142 sp -= 1; /* &argc */
143
144 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
145 sp = (unsigned long __user *)current->mm->start_stack;
146
147 if (put_user(bprm->argc, sp++))
148 return -EFAULT;
149 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
150 unsigned long argv, envp;
151 argv = (unsigned long)(sp + 2);
152 envp = (unsigned long)(sp + 2 + bprm->argc + 1);
153 if (put_user(argv, sp++) || put_user(envp, sp++))
154 return -EFAULT;
155 }
156
157 current->mm->arg_start = (unsigned long)p;
158 for (i = bprm->argc; i > 0; i--) {
159 if (put_user((unsigned long)p, sp++))
160 return -EFAULT;
161 len = strnlen_user(p, MAX_ARG_STRLEN);
162 if (!len || len > MAX_ARG_STRLEN)
163 return -EINVAL;
164 p += len;
165 }
166 if (put_user(0, sp++))
167 return -EFAULT;
168 current->mm->arg_end = (unsigned long)p;
169
170 current->mm->env_start = (unsigned long) p;
171 for (i = bprm->envc; i > 0; i--) {
172 if (put_user((unsigned long)p, sp++))
173 return -EFAULT;
174 len = strnlen_user(p, MAX_ARG_STRLEN);
175 if (!len || len > MAX_ARG_STRLEN)
176 return -EINVAL;
177 p += len;
178 }
179 if (put_user(0, sp++))
180 return -EFAULT;
181 current->mm->env_end = (unsigned long)p;
182
183 return 0;
184}
185
186/****************************************************************************/
187
188#ifdef CONFIG_BINFMT_ZFLAT
189
190#include <linux/zlib.h>
191
192#define LBUFSIZE 4000
193
194/* gzip flag byte */
195#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
196#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
197#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
198#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
199#define COMMENT 0x10 /* bit 4 set: file comment present */
200#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
201#define RESERVED 0xC0 /* bit 6,7: reserved */
202
203static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
204 long len, int fd)
205{
206 unsigned char *buf;
207 z_stream strm;
208 int ret, retval;
209
210 pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
211
212 memset(&strm, 0, sizeof(strm));
213 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
214 if (!strm.workspace)
215 return -ENOMEM;
216
217 buf = kmalloc(LBUFSIZE, GFP_KERNEL);
218 if (!buf) {
219 retval = -ENOMEM;
220 goto out_free;
221 }
222
223 /* Read in first chunk of data and parse gzip header. */
224 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
225
226 strm.next_in = buf;
227 strm.avail_in = ret;
228 strm.total_in = 0;
229
230 retval = -ENOEXEC;
231
232 /* Check minimum size -- gzip header */
233 if (ret < 10) {
234 pr_debug("file too small?\n");
235 goto out_free_buf;
236 }
237
238 /* Check gzip magic number */
239 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
240 pr_debug("unknown compression magic?\n");
241 goto out_free_buf;
242 }
243
244 /* Check gzip method */
245 if (buf[2] != 8) {
246 pr_debug("unknown compression method?\n");
247 goto out_free_buf;
248 }
249 /* Check gzip flags */
250 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
251 (buf[3] & RESERVED)) {
252 pr_debug("unknown flags?\n");
253 goto out_free_buf;
254 }
255
256 ret = 10;
257 if (buf[3] & EXTRA_FIELD) {
258 ret += 2 + buf[10] + (buf[11] << 8);
259 if (unlikely(ret >= LBUFSIZE)) {
260 pr_debug("buffer overflow (EXTRA)?\n");
261 goto out_free_buf;
262 }
263 }
264 if (buf[3] & ORIG_NAME) {
265 while (ret < LBUFSIZE && buf[ret++] != 0)
266 ;
267 if (unlikely(ret == LBUFSIZE)) {
268 pr_debug("buffer overflow (ORIG_NAME)?\n");
269 goto out_free_buf;
270 }
271 }
272 if (buf[3] & COMMENT) {
273 while (ret < LBUFSIZE && buf[ret++] != 0)
274 ;
275 if (unlikely(ret == LBUFSIZE)) {
276 pr_debug("buffer overflow (COMMENT)?\n");
277 goto out_free_buf;
278 }
279 }
280
281 strm.next_in += ret;
282 strm.avail_in -= ret;
283
284 strm.next_out = dst;
285 strm.avail_out = len;
286 strm.total_out = 0;
287
288 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
289 pr_debug("zlib init failed?\n");
290 goto out_free_buf;
291 }
292
293 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
294 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
295 if (ret <= 0)
296 break;
297 len -= ret;
298
299 strm.next_in = buf;
300 strm.avail_in = ret;
301 strm.total_in = 0;
302 }
303
304 if (ret < 0) {
305 pr_debug("decompression failed (%d), %s\n",
306 ret, strm.msg);
307 goto out_zlib;
308 }
309
310 retval = 0;
311out_zlib:
312 zlib_inflateEnd(&strm);
313out_free_buf:
314 kfree(buf);
315out_free:
316 kfree(strm.workspace);
317 return retval;
318}
319
320#endif /* CONFIG_BINFMT_ZFLAT */
321
322/****************************************************************************/
323
324static unsigned long
325calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
326{
327 unsigned long addr;
328 int id;
329 unsigned long start_brk;
330 unsigned long start_data;
331 unsigned long text_len;
332 unsigned long start_code;
333
334#ifdef CONFIG_BINFMT_SHARED_FLAT
335 if (r == 0)
336 id = curid; /* Relocs of 0 are always self referring */
337 else {
338 id = (r >> 24) & 0xff; /* Find ID for this reloc */
339 r &= 0x00ffffff; /* Trim ID off here */
340 }
341 if (id >= MAX_SHARED_LIBS) {
342 pr_err("reference 0x%lx to shared library %d", r, id);
343 goto failed;
344 }
345 if (curid != id) {
346 if (internalp) {
347 pr_err("reloc address 0x%lx not in same module "
348 "(%d != %d)", r, curid, id);
349 goto failed;
350 } else if (!p->lib_list[id].loaded &&
351 load_flat_shared_library(id, p) < 0) {
352 pr_err("failed to load library %d", id);
353 goto failed;
354 }
355 /* Check versioning information (i.e. time stamps) */
356 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
357 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
358 pr_err("library %d is younger than %d", id, curid);
359 goto failed;
360 }
361 }
362#else
363 id = 0;
364#endif
365
366 start_brk = p->lib_list[id].start_brk;
367 start_data = p->lib_list[id].start_data;
368 start_code = p->lib_list[id].start_code;
369 text_len = p->lib_list[id].text_len;
370
371 if (r > start_brk - start_data + text_len) {
372 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
373 r, start_brk-start_data+text_len, text_len);
374 goto failed;
375 }
376
377 if (r < text_len) /* In text segment */
378 addr = r + start_code;
379 else /* In data segment */
380 addr = r - text_len + start_data;
381
382 /* Range checked already above so doing the range tests is redundant...*/
383 return addr;
384
385failed:
386 pr_cont(", killing %s!\n", current->comm);
387 send_sig(SIGSEGV, current, 0);
388
389 return RELOC_FAILED;
390}
391
392/****************************************************************************/
393
394#ifdef CONFIG_BINFMT_FLAT_OLD
395static void old_reloc(unsigned long rl)
396{
397 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
398 flat_v2_reloc_t r;
399 unsigned long __user *ptr;
400 unsigned long val;
401
402 r.value = rl;
403#if defined(CONFIG_COLDFIRE)
404 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
405#else
406 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
407#endif
408 get_user(val, ptr);
409
410 pr_debug("Relocation of variable at DATASEG+%x "
411 "(address %p, currently %lx) into segment %s\n",
412 r.reloc.offset, ptr, val, segment[r.reloc.type]);
413
414 switch (r.reloc.type) {
415 case OLD_FLAT_RELOC_TYPE_TEXT:
416 val += current->mm->start_code;
417 break;
418 case OLD_FLAT_RELOC_TYPE_DATA:
419 val += current->mm->start_data;
420 break;
421 case OLD_FLAT_RELOC_TYPE_BSS:
422 val += current->mm->end_data;
423 break;
424 default:
425 pr_err("Unknown relocation type=%x\n", r.reloc.type);
426 break;
427 }
428 put_user(val, ptr);
429
430 pr_debug("Relocation became %lx\n", val);
431}
432#endif /* CONFIG_BINFMT_FLAT_OLD */
433
434/****************************************************************************/
435
436static int load_flat_file(struct linux_binprm *bprm,
437 struct lib_info *libinfo, int id, unsigned long *extra_stack)
438{
439 struct flat_hdr *hdr;
440 unsigned long textpos, datapos, realdatastart;
441 u32 text_len, data_len, bss_len, stack_len, full_data, flags;
442 unsigned long len, memp, memp_size, extra, rlim;
443 __be32 __user *reloc;
444 u32 __user *rp;
445 int i, rev, relocs;
446 loff_t fpos;
447 unsigned long start_code, end_code;
448 ssize_t result;
449 int ret;
450
451 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
452
453 text_len = ntohl(hdr->data_start);
454 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
455 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
456 stack_len = ntohl(hdr->stack_size);
457 if (extra_stack) {
458 stack_len += *extra_stack;
459 *extra_stack = stack_len;
460 }
461 relocs = ntohl(hdr->reloc_count);
462 flags = ntohl(hdr->flags);
463 rev = ntohl(hdr->rev);
464 full_data = data_len + relocs * sizeof(unsigned long);
465
466 if (strncmp(hdr->magic, "bFLT", 4)) {
467 /*
468 * Previously, here was a printk to tell people
469 * "BINFMT_FLAT: bad header magic".
470 * But for the kernel which also use ELF FD-PIC format, this
471 * error message is confusing.
472 * because a lot of people do not manage to produce good
473 */
474 ret = -ENOEXEC;
475 goto err;
476 }
477
478 if (flags & FLAT_FLAG_KTRACE)
479 pr_info("Loading file: %s\n", bprm->filename);
480
481#ifdef CONFIG_BINFMT_FLAT_OLD
482 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
483 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
484 rev, FLAT_VERSION, OLD_FLAT_VERSION);
485 ret = -ENOEXEC;
486 goto err;
487 }
488
489 /* Don't allow old format executables to use shared libraries */
490 if (rev == OLD_FLAT_VERSION && id != 0) {
491 pr_err("shared libraries are not available before rev 0x%lx\n",
492 FLAT_VERSION);
493 ret = -ENOEXEC;
494 goto err;
495 }
496
497 /*
498 * fix up the flags for the older format, there were all kinds
499 * of endian hacks, this only works for the simple cases
500 */
501 if (rev == OLD_FLAT_VERSION &&
502 (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
503 flags = FLAT_FLAG_RAM;
504
505#else /* CONFIG_BINFMT_FLAT_OLD */
506 if (rev != FLAT_VERSION) {
507 pr_err("bad flat file version 0x%x (supported 0x%lx)\n",
508 rev, FLAT_VERSION);
509 ret = -ENOEXEC;
510 goto err;
511 }
512#endif /* !CONFIG_BINFMT_FLAT_OLD */
513
514 /*
515 * Make sure the header params are sane.
516 * 28 bits (256 MB) is way more than reasonable in this case.
517 * If some top bits are set we have probable binary corruption.
518 */
519 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
520 pr_err("bad header\n");
521 ret = -ENOEXEC;
522 goto err;
523 }
524
525#ifndef CONFIG_BINFMT_ZFLAT
526 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
527 pr_err("Support for ZFLAT executables is not enabled.\n");
528 ret = -ENOEXEC;
529 goto err;
530 }
531#endif
532
533 /*
534 * Check initial limits. This avoids letting people circumvent
535 * size limits imposed on them by creating programs with large
536 * arrays in the data or bss.
537 */
538 rlim = rlimit(RLIMIT_DATA);
539 if (rlim >= RLIM_INFINITY)
540 rlim = ~0;
541 if (data_len + bss_len > rlim) {
542 ret = -ENOMEM;
543 goto err;
544 }
545
546 /* Flush all traces of the currently running executable */
547 if (id == 0) {
548 ret = begin_new_exec(bprm);
549 if (ret)
550 goto err;
551
552 /* OK, This is the point of no return */
553 set_personality(PER_LINUX_32BIT);
554 setup_new_exec(bprm);
555 }
556
557 /*
558 * calculate the extra space we need to map in
559 */
560 extra = max_t(unsigned long, bss_len + stack_len,
561 relocs * sizeof(unsigned long));
562
563 /*
564 * there are a couple of cases here, the separate code/data
565 * case, and then the fully copied to RAM case which lumps
566 * it all together.
567 */
568 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
569 /*
570 * this should give us a ROM ptr, but if it doesn't we don't
571 * really care
572 */
573 pr_debug("ROM mapping of file (we hope)\n");
574
575 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
576 MAP_PRIVATE, 0);
577 if (!textpos || IS_ERR_VALUE(textpos)) {
578 ret = textpos;
579 if (!textpos)
580 ret = -ENOMEM;
581 pr_err("Unable to mmap process text, errno %d\n", ret);
582 goto err;
583 }
584
585 len = data_len + extra +
586 DATA_START_OFFSET_WORDS * sizeof(unsigned long);
587 len = PAGE_ALIGN(len);
588 realdatastart = vm_mmap(NULL, 0, len,
589 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
590
591 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
592 ret = realdatastart;
593 if (!realdatastart)
594 ret = -ENOMEM;
595 pr_err("Unable to allocate RAM for process data, "
596 "errno %d\n", ret);
597 vm_munmap(textpos, text_len);
598 goto err;
599 }
600 datapos = ALIGN(realdatastart +
601 DATA_START_OFFSET_WORDS * sizeof(unsigned long),
602 FLAT_DATA_ALIGN);
603
604 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
605 data_len + bss_len + stack_len, datapos);
606
607 fpos = ntohl(hdr->data_start);
608#ifdef CONFIG_BINFMT_ZFLAT
609 if (flags & FLAT_FLAG_GZDATA) {
610 result = decompress_exec(bprm, fpos, (char *)datapos,
611 full_data, 0);
612 } else
613#endif
614 {
615 result = read_code(bprm->file, datapos, fpos,
616 full_data);
617 }
618 if (IS_ERR_VALUE(result)) {
619 ret = result;
620 pr_err("Unable to read data+bss, errno %d\n", ret);
621 vm_munmap(textpos, text_len);
622 vm_munmap(realdatastart, len);
623 goto err;
624 }
625
626 reloc = (__be32 __user *)
627 (datapos + (ntohl(hdr->reloc_start) - text_len));
628 memp = realdatastart;
629 memp_size = len;
630 } else {
631
632 len = text_len + data_len + extra +
633 DATA_START_OFFSET_WORDS * sizeof(u32);
634 len = PAGE_ALIGN(len);
635 textpos = vm_mmap(NULL, 0, len,
636 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
637
638 if (!textpos || IS_ERR_VALUE(textpos)) {
639 ret = textpos;
640 if (!textpos)
641 ret = -ENOMEM;
642 pr_err("Unable to allocate RAM for process text/data, "
643 "errno %d\n", ret);
644 goto err;
645 }
646
647 realdatastart = textpos + ntohl(hdr->data_start);
648 datapos = ALIGN(realdatastart +
649 DATA_START_OFFSET_WORDS * sizeof(u32),
650 FLAT_DATA_ALIGN);
651
652 reloc = (__be32 __user *)
653 (datapos + (ntohl(hdr->reloc_start) - text_len));
654 memp = textpos;
655 memp_size = len;
656#ifdef CONFIG_BINFMT_ZFLAT
657 /*
658 * load it all in and treat it like a RAM load from now on
659 */
660 if (flags & FLAT_FLAG_GZIP) {
661#ifndef CONFIG_MMU
662 result = decompress_exec(bprm, sizeof(struct flat_hdr),
663 (((char *)textpos) + sizeof(struct flat_hdr)),
664 (text_len + full_data
665 - sizeof(struct flat_hdr)),
666 0);
667 memmove((void *) datapos, (void *) realdatastart,
668 full_data);
669#else
670 /*
671 * This is used on MMU systems mainly for testing.
672 * Let's use a kernel buffer to simplify things.
673 */
674 long unz_text_len = text_len - sizeof(struct flat_hdr);
675 long unz_len = unz_text_len + full_data;
676 char *unz_data = vmalloc(unz_len);
677 if (!unz_data) {
678 result = -ENOMEM;
679 } else {
680 result = decompress_exec(bprm, sizeof(struct flat_hdr),
681 unz_data, unz_len, 0);
682 if (result == 0 &&
683 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
684 unz_data, unz_text_len) ||
685 copy_to_user((void __user *)datapos,
686 unz_data + unz_text_len, full_data)))
687 result = -EFAULT;
688 vfree(unz_data);
689 }
690#endif
691 } else if (flags & FLAT_FLAG_GZDATA) {
692 result = read_code(bprm->file, textpos, 0, text_len);
693 if (!IS_ERR_VALUE(result)) {
694#ifndef CONFIG_MMU
695 result = decompress_exec(bprm, text_len, (char *) datapos,
696 full_data, 0);
697#else
698 char *unz_data = vmalloc(full_data);
699 if (!unz_data) {
700 result = -ENOMEM;
701 } else {
702 result = decompress_exec(bprm, text_len,
703 unz_data, full_data, 0);
704 if (result == 0 &&
705 copy_to_user((void __user *)datapos,
706 unz_data, full_data))
707 result = -EFAULT;
708 vfree(unz_data);
709 }
710#endif
711 }
712 } else
713#endif /* CONFIG_BINFMT_ZFLAT */
714 {
715 result = read_code(bprm->file, textpos, 0, text_len);
716 if (!IS_ERR_VALUE(result))
717 result = read_code(bprm->file, datapos,
718 ntohl(hdr->data_start),
719 full_data);
720 }
721 if (IS_ERR_VALUE(result)) {
722 ret = result;
723 pr_err("Unable to read code+data+bss, errno %d\n", ret);
724 vm_munmap(textpos, text_len + data_len + extra +
725 DATA_START_OFFSET_WORDS * sizeof(u32));
726 goto err;
727 }
728 }
729
730 start_code = textpos + sizeof(struct flat_hdr);
731 end_code = textpos + text_len;
732 text_len -= sizeof(struct flat_hdr); /* the real code len */
733
734 /* The main program needs a little extra setup in the task structure */
735 if (id == 0) {
736 current->mm->start_code = start_code;
737 current->mm->end_code = end_code;
738 current->mm->start_data = datapos;
739 current->mm->end_data = datapos + data_len;
740 /*
741 * set up the brk stuff, uses any slack left in data/bss/stack
742 * allocation. We put the brk after the bss (between the bss
743 * and stack) like other platforms.
744 * Userspace code relies on the stack pointer starting out at
745 * an address right at the end of a page.
746 */
747 current->mm->start_brk = datapos + data_len + bss_len;
748 current->mm->brk = (current->mm->start_brk + 3) & ~3;
749#ifndef CONFIG_MMU
750 current->mm->context.end_brk = memp + memp_size - stack_len;
751#endif
752 }
753
754 if (flags & FLAT_FLAG_KTRACE) {
755 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
756 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
757 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
758 id ? "Lib" : "Load", bprm->filename,
759 start_code, end_code, datapos, datapos + data_len,
760 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
761 }
762
763 /* Store the current module values into the global library structure */
764 libinfo->lib_list[id].start_code = start_code;
765 libinfo->lib_list[id].start_data = datapos;
766 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
767 libinfo->lib_list[id].text_len = text_len;
768 libinfo->lib_list[id].loaded = 1;
769 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
770 libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
771
772 /*
773 * We just load the allocations into some temporary memory to
774 * help simplify all this mumbo jumbo
775 *
776 * We've got two different sections of relocation entries.
777 * The first is the GOT which resides at the beginning of the data segment
778 * and is terminated with a -1. This one can be relocated in place.
779 * The second is the extra relocation entries tacked after the image's
780 * data segment. These require a little more processing as the entry is
781 * really an offset into the image which contains an offset into the
782 * image.
783 */
784 if (flags & FLAT_FLAG_GOTPIC) {
785 for (rp = (u32 __user *)datapos; ; rp++) {
786 u32 addr, rp_val;
787 if (get_user(rp_val, rp))
788 return -EFAULT;
789 if (rp_val == 0xffffffff)
790 break;
791 if (rp_val) {
792 addr = calc_reloc(rp_val, libinfo, id, 0);
793 if (addr == RELOC_FAILED) {
794 ret = -ENOEXEC;
795 goto err;
796 }
797 if (put_user(addr, rp))
798 return -EFAULT;
799 }
800 }
801 }
802
803 /*
804 * Now run through the relocation entries.
805 * We've got to be careful here as C++ produces relocatable zero
806 * entries in the constructor and destructor tables which are then
807 * tested for being not zero (which will always occur unless we're
808 * based from address zero). This causes an endless loop as __start
809 * is at zero. The solution used is to not relocate zero addresses.
810 * This has the negative side effect of not allowing a global data
811 * reference to be statically initialised to _stext (I've moved
812 * __start to address 4 so that is okay).
813 */
814 if (rev > OLD_FLAT_VERSION) {
815 for (i = 0; i < relocs; i++) {
816 u32 addr, relval;
817 __be32 tmp;
818
819 /*
820 * Get the address of the pointer to be
821 * relocated (of course, the address has to be
822 * relocated first).
823 */
824 if (get_user(tmp, reloc + i))
825 return -EFAULT;
826 relval = ntohl(tmp);
827 addr = flat_get_relocate_addr(relval);
828 rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
829 if (rp == (u32 __user *)RELOC_FAILED) {
830 ret = -ENOEXEC;
831 goto err;
832 }
833
834 /* Get the pointer's value. */
835 ret = flat_get_addr_from_rp(rp, relval, flags, &addr);
836 if (unlikely(ret))
837 goto err;
838
839 if (addr != 0) {
840 /*
841 * Do the relocation. PIC relocs in the data section are
842 * already in target order
843 */
844 if ((flags & FLAT_FLAG_GOTPIC) == 0) {
845 /*
846 * Meh, the same value can have a different
847 * byte order based on a flag..
848 */
849 addr = ntohl((__force __be32)addr);
850 }
851 addr = calc_reloc(addr, libinfo, id, 0);
852 if (addr == RELOC_FAILED) {
853 ret = -ENOEXEC;
854 goto err;
855 }
856
857 /* Write back the relocated pointer. */
858 ret = flat_put_addr_at_rp(rp, addr, relval);
859 if (unlikely(ret))
860 goto err;
861 }
862 }
863#ifdef CONFIG_BINFMT_FLAT_OLD
864 } else {
865 for (i = 0; i < relocs; i++) {
866 __be32 relval;
867 if (get_user(relval, reloc + i))
868 return -EFAULT;
869 old_reloc(ntohl(relval));
870 }
871#endif /* CONFIG_BINFMT_FLAT_OLD */
872 }
873
874 flush_icache_user_range(start_code, end_code);
875
876 /* zero the BSS, BRK and stack areas */
877 if (clear_user((void __user *)(datapos + data_len), bss_len +
878 (memp + memp_size - stack_len - /* end brk */
879 libinfo->lib_list[id].start_brk) + /* start brk */
880 stack_len))
881 return -EFAULT;
882
883 return 0;
884err:
885 return ret;
886}
887
888
889/****************************************************************************/
890#ifdef CONFIG_BINFMT_SHARED_FLAT
891
892/*
893 * Load a shared library into memory. The library gets its own data
894 * segment (including bss) but not argv/argc/environ.
895 */
896
897static int load_flat_shared_library(int id, struct lib_info *libs)
898{
899 /*
900 * This is a fake bprm struct; only the members "buf", "file" and
901 * "filename" are actually used.
902 */
903 struct linux_binprm bprm;
904 int res;
905 char buf[16];
906 loff_t pos = 0;
907
908 memset(&bprm, 0, sizeof(bprm));
909
910 /* Create the file name */
911 sprintf(buf, "/lib/lib%d.so", id);
912
913 /* Open the file up */
914 bprm.filename = buf;
915 bprm.file = open_exec(bprm.filename);
916 res = PTR_ERR(bprm.file);
917 if (IS_ERR(bprm.file))
918 return res;
919
920 res = kernel_read(bprm.file, bprm.buf, BINPRM_BUF_SIZE, &pos);
921
922 if (res >= 0)
923 res = load_flat_file(&bprm, libs, id, NULL);
924
925 allow_write_access(bprm.file);
926 fput(bprm.file);
927
928 return res;
929}
930
931#endif /* CONFIG_BINFMT_SHARED_FLAT */
932/****************************************************************************/
933
934/*
935 * These are the functions used to load flat style executables and shared
936 * libraries. There is no binary dependent code anywhere else.
937 */
938
939static int load_flat_binary(struct linux_binprm *bprm)
940{
941 struct lib_info libinfo;
942 struct pt_regs *regs = current_pt_regs();
943 unsigned long stack_len = 0;
944 unsigned long start_addr;
945 int res;
946 int i, j;
947
948 memset(&libinfo, 0, sizeof(libinfo));
949
950 /*
951 * We have to add the size of our arguments to our stack size
952 * otherwise it's too easy for users to create stack overflows
953 * by passing in a huge argument list. And yes, we have to be
954 * pedantic and include space for the argv/envp array as it may have
955 * a lot of entries.
956 */
957#ifndef CONFIG_MMU
958 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
959#endif
960 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
961 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
962 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
963
964 res = load_flat_file(bprm, &libinfo, 0, &stack_len);
965 if (res < 0)
966 return res;
967
968 /* Update data segment pointers for all libraries */
969 for (i = 0; i < MAX_SHARED_LIBS; i++) {
970 if (!libinfo.lib_list[i].loaded)
971 continue;
972 for (j = 0; j < MAX_SHARED_LIBS; j++) {
973 unsigned long val = libinfo.lib_list[j].loaded ?
974 libinfo.lib_list[j].start_data : UNLOADED_LIB;
975 unsigned long __user *p = (unsigned long __user *)
976 libinfo.lib_list[i].start_data;
977 p -= j + 1;
978 if (put_user(val, p))
979 return -EFAULT;
980 }
981 }
982
983 set_binfmt(&flat_format);
984
985#ifdef CONFIG_MMU
986 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
987 if (!res)
988 res = create_flat_tables(bprm, bprm->p);
989#else
990 /* Stash our initial stack pointer into the mm structure */
991 current->mm->start_stack =
992 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
993 pr_debug("sp=%lx\n", current->mm->start_stack);
994
995 /* copy the arg pages onto the stack */
996 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack);
997 if (!res)
998 res = create_flat_tables(bprm, current->mm->start_stack);
999#endif
1000 if (res)
1001 return res;
1002
1003 /* Fake some return addresses to ensure the call chain will
1004 * initialise library in order for us. We are required to call
1005 * lib 1 first, then 2, ... and finally the main program (id 0).
1006 */
1007 start_addr = libinfo.lib_list[0].entry;
1008
1009#ifdef CONFIG_BINFMT_SHARED_FLAT
1010 for (i = MAX_SHARED_LIBS-1; i > 0; i--) {
1011 if (libinfo.lib_list[i].loaded) {
1012 /* Push previos first to call address */
1013 unsigned long __user *sp;
1014 current->mm->start_stack -= sizeof(unsigned long);
1015 sp = (unsigned long __user *)current->mm->start_stack;
1016 if (put_user(start_addr, sp))
1017 return -EFAULT;
1018 start_addr = libinfo.lib_list[i].entry;
1019 }
1020 }
1021#endif
1022
1023#ifdef FLAT_PLAT_INIT
1024 FLAT_PLAT_INIT(regs);
1025#endif
1026
1027 finalize_exec(bprm);
1028 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
1029 regs, start_addr, current->mm->start_stack);
1030 start_thread(regs, start_addr, current->mm->start_stack);
1031
1032 return 0;
1033}
1034
1035/****************************************************************************/
1036
1037static int __init init_flat_binfmt(void)
1038{
1039 register_binfmt(&flat_format);
1040 return 0;
1041}
1042core_initcall(init_flat_binfmt);
1043
1044/****************************************************************************/