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