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