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tcp: add tcp_min_snd_mss sysctl
[linux-stable.git] / fs / binfmt_flat.c
blob5d6b94475f272629dc3f8c252749aff08790766d
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
46 /****************************************************************************/
47
48 /*
49 * User data (data section and bss) needs to be aligned.
50 * We pick 0x20 here because it is the max value elf2flt has always
51 * used in producing FLAT files, and because it seems to be large
52 * enough to make all the gcc alignment related tests happy.
53 */
54 #define FLAT_DATA_ALIGN (0x20)
55
56 /*
57 * User data (stack) also needs to be aligned.
58 * Here we can be a bit looser than the data sections since this
59 * needs to only meet arch ABI requirements.
60 */
61 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
62
63 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
64 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
65
66 struct lib_info {
67 struct {
68 unsigned long start_code; /* Start of text segment */
69 unsigned long start_data; /* Start of data segment */
70 unsigned long start_brk; /* End of data segment */
71 unsigned long text_len; /* Length of text segment */
72 unsigned long entry; /* Start address for this module */
73 unsigned long build_date; /* When this one was compiled */
74 bool loaded; /* Has this library been loaded? */
75 } lib_list[MAX_SHARED_LIBS];
76 };
77
78 #ifdef CONFIG_BINFMT_SHARED_FLAT
79 static int load_flat_shared_library(int id, struct lib_info *p);
80 #endif
81
82 static int load_flat_binary(struct linux_binprm *);
83 static int flat_core_dump(struct coredump_params *cprm);
84
85 static struct linux_binfmt flat_format = {
86 .module = THIS_MODULE,
87 .load_binary = load_flat_binary,
88 .core_dump = flat_core_dump,
89 .min_coredump = PAGE_SIZE
90 };
91
92 /****************************************************************************/
93 /*
94 * Routine writes a core dump image in the current directory.
95 * Currently only a stub-function.
96 */
97
98 static int flat_core_dump(struct coredump_params *cprm)
99 {
100 pr_warn("Process %s:%d received signr %d and should have core dumped\n",
101 current->comm, current->pid, cprm->siginfo->si_signo);
102 return 1;
103 }
104
105 /****************************************************************************/
106 /*
107 * create_flat_tables() parses the env- and arg-strings in new user
108 * memory and creates the pointer tables from them, and puts their
109 * addresses on the "stack", recording the new stack pointer value.
110 */
111
112 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
113 {
114 char __user *p;
115 unsigned long __user *sp;
116 long i, len;
117
118 p = (char __user *)arg_start;
119 sp = (unsigned long __user *)current->mm->start_stack;
120
121 sp -= bprm->envc + 1;
122 sp -= bprm->argc + 1;
123 sp -= flat_argvp_envp_on_stack() ? 2 : 0;
124 sp -= 1; /* &argc */
125
126 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
127 sp = (unsigned long __user *)current->mm->start_stack;
128
129 __put_user(bprm->argc, sp++);
130 if (flat_argvp_envp_on_stack()) {
131 unsigned long argv, envp;
132 argv = (unsigned long)(sp + 2);
133 envp = (unsigned long)(sp + 2 + bprm->argc + 1);
134 __put_user(argv, sp++);
135 __put_user(envp, sp++);
136 }
137
138 current->mm->arg_start = (unsigned long)p;
139 for (i = bprm->argc; i > 0; i--) {
140 __put_user((unsigned long)p, sp++);
141 len = strnlen_user(p, MAX_ARG_STRLEN);
142 if (!len || len > MAX_ARG_STRLEN)
143 return -EINVAL;
144 p += len;
145 }
146 __put_user(0, sp++);
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 __put_user((unsigned long)p, sp++);
152 len = strnlen_user(p, MAX_ARG_STRLEN);
153 if (!len || len > MAX_ARG_STRLEN)
154 return -EINVAL;
155 p += len;
156 }
157 __put_user(0, sp++);
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
180 static 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;
288 out_zlib:
289 zlib_inflateEnd(&strm);
290 out_free_buf:
291 kfree(buf);
292 out_free:
293 kfree(strm.workspace);
294 return retval;
295 }
296
297 #endif /* CONFIG_BINFMT_ZFLAT */
298
299 /****************************************************************************/
300
301 static unsigned long
302 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
303 {
304 unsigned long addr;
305 int id;
306 unsigned long start_brk;
307 unsigned long start_data;
308 unsigned long text_len;
309 unsigned long start_code;
310
311 #ifdef CONFIG_BINFMT_SHARED_FLAT
312 if (r == 0)
313 id = curid; /* Relocs of 0 are always self referring */
314 else {
315 id = (r >> 24) & 0xff; /* Find ID for this reloc */
316 r &= 0x00ffffff; /* Trim ID off here */
317 }
318 if (id >= MAX_SHARED_LIBS) {
319 pr_err("reference 0x%lx to shared library %d", r, id);
320 goto failed;
321 }
322 if (curid != id) {
323 if (internalp) {
324 pr_err("reloc address 0x%lx not in same module "
325 "(%d != %d)", r, curid, id);
326 goto failed;
327 } else if (!p->lib_list[id].loaded &&
328 load_flat_shared_library(id, p) < 0) {
329 pr_err("failed to load library %d", id);
330 goto failed;
331 }
332 /* Check versioning information (i.e. time stamps) */
333 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
334 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
335 pr_err("library %d is younger than %d", id, curid);
336 goto failed;
337 }
338 }
339 #else
340 id = 0;
341 #endif
342
343 start_brk = p->lib_list[id].start_brk;
344 start_data = p->lib_list[id].start_data;
345 start_code = p->lib_list[id].start_code;
346 text_len = p->lib_list[id].text_len;
347
348 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
349 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
350 r, start_brk-start_data+text_len, text_len);
351 goto failed;
352 }
353
354 if (r < text_len) /* In text segment */
355 addr = r + start_code;
356 else /* In data segment */
357 addr = r - text_len + start_data;
358
359 /* Range checked already above so doing the range tests is redundant...*/
360 return addr;
361
362 failed:
363 pr_cont(", killing %s!\n", current->comm);
364 send_sig(SIGSEGV, current, 0);
365
366 return RELOC_FAILED;
367 }
368
369 /****************************************************************************/
370
371 static void old_reloc(unsigned long rl)
372 {
373 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
374 flat_v2_reloc_t r;
375 unsigned long __user *ptr;
376 unsigned long val;
377
378 r.value = rl;
379 #if defined(CONFIG_COLDFIRE)
380 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
381 #else
382 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
383 #endif
384 get_user(val, ptr);
385
386 pr_debug("Relocation of variable at DATASEG+%x "
387 "(address %p, currently %lx) into segment %s\n",
388 r.reloc.offset, ptr, val, segment[r.reloc.type]);
389
390 switch (r.reloc.type) {
391 case OLD_FLAT_RELOC_TYPE_TEXT:
392 val += current->mm->start_code;
393 break;
394 case OLD_FLAT_RELOC_TYPE_DATA:
395 val += current->mm->start_data;
396 break;
397 case OLD_FLAT_RELOC_TYPE_BSS:
398 val += current->mm->end_data;
399 break;
400 default:
401 pr_err("Unknown relocation type=%x\n", r.reloc.type);
402 break;
403 }
404 put_user(val, ptr);
405
406 pr_debug("Relocation became %lx\n", val);
407 }
408
409 /****************************************************************************/
410
411 static int load_flat_file(struct linux_binprm *bprm,
412 struct lib_info *libinfo, int id, unsigned long *extra_stack)
413 {
414 struct flat_hdr *hdr;
415 unsigned long textpos, datapos, realdatastart;
416 u32 text_len, data_len, bss_len, stack_len, full_data, flags;
417 unsigned long len, memp, memp_size, extra, rlim;
418 u32 __user *reloc, *rp;
419 struct inode *inode;
420 int i, rev, relocs;
421 loff_t fpos;
422 unsigned long start_code, end_code;
423 ssize_t result;
424 int ret;
425
426 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
427 inode = file_inode(bprm->file);
428
429 text_len = ntohl(hdr->data_start);
430 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
431 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
432 stack_len = ntohl(hdr->stack_size);
433 if (extra_stack) {
434 stack_len += *extra_stack;
435 *extra_stack = stack_len;
436 }
437 relocs = ntohl(hdr->reloc_count);
438 flags = ntohl(hdr->flags);
439 rev = ntohl(hdr->rev);
440 full_data = data_len + relocs * sizeof(unsigned long);
441
442 if (strncmp(hdr->magic, "bFLT", 4)) {
443 /*
444 * Previously, here was a printk to tell people
445 * "BINFMT_FLAT: bad header magic".
446 * But for the kernel which also use ELF FD-PIC format, this
447 * error message is confusing.
448 * because a lot of people do not manage to produce good
449 */
450 ret = -ENOEXEC;
451 goto err;
452 }
453
454 if (flags & FLAT_FLAG_KTRACE)
455 pr_info("Loading file: %s\n", bprm->filename);
456
457 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
458 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
459 rev, FLAT_VERSION, OLD_FLAT_VERSION);
460 ret = -ENOEXEC;
461 goto err;
462 }
463
464 /* Don't allow old format executables to use shared libraries */
465 if (rev == OLD_FLAT_VERSION && id != 0) {
466 pr_err("shared libraries are not available before rev 0x%lx\n",
467 FLAT_VERSION);
468 ret = -ENOEXEC;
469 goto err;
470 }
471
472 /*
473 * Make sure the header params are sane.
474 * 28 bits (256 MB) is way more than reasonable in this case.
475 * If some top bits are set we have probable binary corruption.
476 */
477 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
478 pr_err("bad header\n");
479 ret = -ENOEXEC;
480 goto err;
481 }
482
483 /*
484 * fix up the flags for the older format, there were all kinds
485 * of endian hacks, this only works for the simple cases
486 */
487 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
488 flags = FLAT_FLAG_RAM;
489
490 #ifndef CONFIG_BINFMT_ZFLAT
491 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
492 pr_err("Support for ZFLAT executables is not enabled.\n");
493 ret = -ENOEXEC;
494 goto err;
495 }
496 #endif
497
498 /*
499 * Check initial limits. This avoids letting people circumvent
500 * size limits imposed on them by creating programs with large
501 * arrays in the data or bss.
502 */
503 rlim = rlimit(RLIMIT_DATA);
504 if (rlim >= RLIM_INFINITY)
505 rlim = ~0;
506 if (data_len + bss_len > rlim) {
507 ret = -ENOMEM;
508 goto err;
509 }
510
511 /* Flush all traces of the currently running executable */
512 if (id == 0) {
513 ret = flush_old_exec(bprm);
514 if (ret)
515 goto err;
516
517 /* OK, This is the point of no return */
518 set_personality(PER_LINUX_32BIT);
519 setup_new_exec(bprm);
520 }
521
522 /*
523 * calculate the extra space we need to map in
524 */
525 extra = max_t(unsigned long, bss_len + stack_len,
526 relocs * sizeof(unsigned long));
527
528 /*
529 * there are a couple of cases here, the separate code/data
530 * case, and then the fully copied to RAM case which lumps
531 * it all together.
532 */
533 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
534 /*
535 * this should give us a ROM ptr, but if it doesn't we don't
536 * really care
537 */
538 pr_debug("ROM mapping of file (we hope)\n");
539
540 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
541 MAP_PRIVATE|MAP_EXECUTABLE, 0);
542 if (!textpos || IS_ERR_VALUE(textpos)) {
543 ret = textpos;
544 if (!textpos)
545 ret = -ENOMEM;
546 pr_err("Unable to mmap process text, errno %d\n", ret);
547 goto err;
548 }
549
550 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
551 len = PAGE_ALIGN(len);
552 realdatastart = vm_mmap(NULL, 0, len,
553 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
554
555 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
556 ret = realdatastart;
557 if (!realdatastart)
558 ret = -ENOMEM;
559 pr_err("Unable to allocate RAM for process data, "
560 "errno %d\n", ret);
561 vm_munmap(textpos, text_len);
562 goto err;
563 }
564 datapos = ALIGN(realdatastart +
565 MAX_SHARED_LIBS * sizeof(unsigned long),
566 FLAT_DATA_ALIGN);
567
568 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
569 data_len + bss_len + stack_len, datapos);
570
571 fpos = ntohl(hdr->data_start);
572 #ifdef CONFIG_BINFMT_ZFLAT
573 if (flags & FLAT_FLAG_GZDATA) {
574 result = decompress_exec(bprm, fpos, (char *)datapos,
575 full_data, 0);
576 } else
577 #endif
578 {
579 result = read_code(bprm->file, datapos, fpos,
580 full_data);
581 }
582 if (IS_ERR_VALUE(result)) {
583 ret = result;
584 pr_err("Unable to read data+bss, errno %d\n", ret);
585 vm_munmap(textpos, text_len);
586 vm_munmap(realdatastart, len);
587 goto err;
588 }
589
590 reloc = (u32 __user *)
591 (datapos + (ntohl(hdr->reloc_start) - text_len));
592 memp = realdatastart;
593 memp_size = len;
594 } else {
595
596 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32);
597 len = PAGE_ALIGN(len);
598 textpos = vm_mmap(NULL, 0, len,
599 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
600
601 if (!textpos || IS_ERR_VALUE(textpos)) {
602 ret = textpos;
603 if (!textpos)
604 ret = -ENOMEM;
605 pr_err("Unable to allocate RAM for process text/data, "
606 "errno %d\n", ret);
607 goto err;
608 }
609
610 realdatastart = textpos + ntohl(hdr->data_start);
611 datapos = ALIGN(realdatastart +
612 MAX_SHARED_LIBS * sizeof(u32),
613 FLAT_DATA_ALIGN);
614
615 reloc = (u32 __user *)
616 (datapos + (ntohl(hdr->reloc_start) - text_len));
617 memp = textpos;
618 memp_size = len;
619 #ifdef CONFIG_BINFMT_ZFLAT
620 /*
621 * load it all in and treat it like a RAM load from now on
622 */
623 if (flags & FLAT_FLAG_GZIP) {
624 #ifndef CONFIG_MMU
625 result = decompress_exec(bprm, sizeof(struct flat_hdr),
626 (((char *)textpos) + sizeof(struct flat_hdr)),
627 (text_len + full_data
628 - sizeof(struct flat_hdr)),
629 0);
630 memmove((void *) datapos, (void *) realdatastart,
631 full_data);
632 #else
633 /*
634 * This is used on MMU systems mainly for testing.
635 * Let's use a kernel buffer to simplify things.
636 */
637 long unz_text_len = text_len - sizeof(struct flat_hdr);
638 long unz_len = unz_text_len + full_data;
639 char *unz_data = vmalloc(unz_len);
640 if (!unz_data) {
641 result = -ENOMEM;
642 } else {
643 result = decompress_exec(bprm, sizeof(struct flat_hdr),
644 unz_data, unz_len, 0);
645 if (result == 0 &&
646 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
647 unz_data, unz_text_len) ||
648 copy_to_user((void __user *)datapos,
649 unz_data + unz_text_len, full_data)))
650 result = -EFAULT;
651 vfree(unz_data);
652 }
653 #endif
654 } else if (flags & FLAT_FLAG_GZDATA) {
655 result = read_code(bprm->file, textpos, 0, text_len);
656 if (!IS_ERR_VALUE(result)) {
657 #ifndef CONFIG_MMU
658 result = decompress_exec(bprm, text_len, (char *) datapos,
659 full_data, 0);
660 #else
661 char *unz_data = vmalloc(full_data);
662 if (!unz_data) {
663 result = -ENOMEM;
664 } else {
665 result = decompress_exec(bprm, text_len,
666 unz_data, full_data, 0);
667 if (result == 0 &&
668 copy_to_user((void __user *)datapos,
669 unz_data, full_data))
670 result = -EFAULT;
671 vfree(unz_data);
672 }
673 #endif
674 }
675 } else
676 #endif /* CONFIG_BINFMT_ZFLAT */
677 {
678 result = read_code(bprm->file, textpos, 0, text_len);
679 if (!IS_ERR_VALUE(result))
680 result = read_code(bprm->file, datapos,
681 ntohl(hdr->data_start),
682 full_data);
683 }
684 if (IS_ERR_VALUE(result)) {
685 ret = result;
686 pr_err("Unable to read code+data+bss, errno %d\n", ret);
687 vm_munmap(textpos, text_len + data_len + extra +
688 MAX_SHARED_LIBS * sizeof(u32));
689 goto err;
690 }
691 }
692
693 start_code = textpos + sizeof(struct flat_hdr);
694 end_code = textpos + text_len;
695 text_len -= sizeof(struct flat_hdr); /* the real code len */
696
697 /* The main program needs a little extra setup in the task structure */
698 if (id == 0) {
699 current->mm->start_code = start_code;
700 current->mm->end_code = end_code;
701 current->mm->start_data = datapos;
702 current->mm->end_data = datapos + data_len;
703 /*
704 * set up the brk stuff, uses any slack left in data/bss/stack
705 * allocation. We put the brk after the bss (between the bss
706 * and stack) like other platforms.
707 * Userspace code relies on the stack pointer starting out at
708 * an address right at the end of a page.
709 */
710 current->mm->start_brk = datapos + data_len + bss_len;
711 current->mm->brk = (current->mm->start_brk + 3) & ~3;
712 #ifndef CONFIG_MMU
713 current->mm->context.end_brk = memp + memp_size - stack_len;
714 #endif
715 }
716
717 if (flags & FLAT_FLAG_KTRACE) {
718 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
719 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
720 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
721 id ? "Lib" : "Load", bprm->filename,
722 start_code, end_code, datapos, datapos + data_len,
723 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
724 }
725
726 /* Store the current module values into the global library structure */
727 libinfo->lib_list[id].start_code = start_code;
728 libinfo->lib_list[id].start_data = datapos;
729 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
730 libinfo->lib_list[id].text_len = text_len;
731 libinfo->lib_list[id].loaded = 1;
732 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
733 libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
734
735 /*
736 * We just load the allocations into some temporary memory to
737 * help simplify all this mumbo jumbo
738 *
739 * We've got two different sections of relocation entries.
740 * The first is the GOT which resides at the beginning of the data segment
741 * and is terminated with a -1. This one can be relocated in place.
742 * The second is the extra relocation entries tacked after the image's
743 * data segment. These require a little more processing as the entry is
744 * really an offset into the image which contains an offset into the
745 * image.
746 */
747 if (flags & FLAT_FLAG_GOTPIC) {
748 for (rp = (u32 __user *)datapos; ; rp++) {
749 u32 addr, rp_val;
750 if (get_user(rp_val, rp))
751 return -EFAULT;
752 if (rp_val == 0xffffffff)
753 break;
754 if (rp_val) {
755 addr = calc_reloc(rp_val, libinfo, id, 0);
756 if (addr == RELOC_FAILED) {
757 ret = -ENOEXEC;
758 goto err;
759 }
760 if (put_user(addr, rp))
761 return -EFAULT;
762 }
763 }
764 }
765
766 /*
767 * Now run through the relocation entries.
768 * We've got to be careful here as C++ produces relocatable zero
769 * entries in the constructor and destructor tables which are then
770 * tested for being not zero (which will always occur unless we're
771 * based from address zero). This causes an endless loop as __start
772 * is at zero. The solution used is to not relocate zero addresses.
773 * This has the negative side effect of not allowing a global data
774 * reference to be statically initialised to _stext (I've moved
775 * __start to address 4 so that is okay).
776 */
777 if (rev > OLD_FLAT_VERSION) {
778 u32 __maybe_unused persistent = 0;
779 for (i = 0; i < relocs; i++) {
780 u32 addr, relval;
781
782 /*
783 * Get the address of the pointer to be
784 * relocated (of course, the address has to be
785 * relocated first).
786 */
787 if (get_user(relval, reloc + i))
788 return -EFAULT;
789 relval = ntohl(relval);
790 if (flat_set_persistent(relval, &persistent))
791 continue;
792 addr = flat_get_relocate_addr(relval);
793 rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
794 if (rp == (u32 __user *)RELOC_FAILED) {
795 ret = -ENOEXEC;
796 goto err;
797 }
798
799 /* Get the pointer's value. */
800 ret = flat_get_addr_from_rp(rp, relval, flags,
801 &addr, &persistent);
802 if (unlikely(ret))
803 goto err;
804
805 if (addr != 0) {
806 /*
807 * Do the relocation. PIC relocs in the data section are
808 * already in target order
809 */
810 if ((flags & FLAT_FLAG_GOTPIC) == 0)
811 addr = ntohl(addr);
812 addr = calc_reloc(addr, libinfo, id, 0);
813 if (addr == RELOC_FAILED) {
814 ret = -ENOEXEC;
815 goto err;
816 }
817
818 /* Write back the relocated pointer. */
819 ret = flat_put_addr_at_rp(rp, addr, relval);
820 if (unlikely(ret))
821 goto err;
822 }
823 }
824 } else {
825 for (i = 0; i < relocs; i++) {
826 u32 relval;
827 if (get_user(relval, reloc + i))
828 return -EFAULT;
829 relval = ntohl(relval);
830 old_reloc(relval);
831 }
832 }
833
834 flush_icache_range(start_code, end_code);
835
836 /* zero the BSS, BRK and stack areas */
837 if (clear_user((void __user *)(datapos + data_len), bss_len +
838 (memp + memp_size - stack_len - /* end brk */
839 libinfo->lib_list[id].start_brk) + /* start brk */
840 stack_len))
841 return -EFAULT;
842
843 return 0;
844 err:
845 return ret;
846 }
847
848
849 /****************************************************************************/
850 #ifdef CONFIG_BINFMT_SHARED_FLAT
851
852 /*
853 * Load a shared library into memory. The library gets its own data
854 * segment (including bss) but not argv/argc/environ.
855 */
856
857 static int load_flat_shared_library(int id, struct lib_info *libs)
858 {
859 struct linux_binprm bprm;
860 int res;
861 char buf[16];
862
863 memset(&bprm, 0, sizeof(bprm));
864
865 /* Create the file name */
866 sprintf(buf, "/lib/lib%d.so", id);
867
868 /* Open the file up */
869 bprm.filename = buf;
870 bprm.file = open_exec(bprm.filename);
871 res = PTR_ERR(bprm.file);
872 if (IS_ERR(bprm.file))
873 return res;
874
875 bprm.cred = prepare_exec_creds();
876 res = -ENOMEM;
877 if (!bprm.cred)
878 goto out;
879
880 /* We don't really care about recalculating credentials at this point
881 * as we're past the point of no return and are dealing with shared
882 * libraries.
883 */
884 bprm.called_set_creds = 1;
885
886 res = prepare_binprm(&bprm);
887
888 if (!res)
889 res = load_flat_file(&bprm, libs, id, NULL);
890
891 abort_creds(bprm.cred);
892
893 out:
894 allow_write_access(bprm.file);
895 fput(bprm.file);
896
897 return res;
898 }
899
900 #endif /* CONFIG_BINFMT_SHARED_FLAT */
901 /****************************************************************************/
902
903 /*
904 * These are the functions used to load flat style executables and shared
905 * libraries. There is no binary dependent code anywhere else.
906 */
907
908 static int load_flat_binary(struct linux_binprm *bprm)
909 {
910 struct lib_info libinfo;
911 struct pt_regs *regs = current_pt_regs();
912 unsigned long stack_len = 0;
913 unsigned long start_addr;
914 int res;
915 int i, j;
916
917 memset(&libinfo, 0, sizeof(libinfo));
918
919 /*
920 * We have to add the size of our arguments to our stack size
921 * otherwise it's too easy for users to create stack overflows
922 * by passing in a huge argument list. And yes, we have to be
923 * pedantic and include space for the argv/envp array as it may have
924 * a lot of entries.
925 */
926 #ifndef CONFIG_MMU
927 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
928 #endif
929 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
930 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
931 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
932
933 res = load_flat_file(bprm, &libinfo, 0, &stack_len);
934 if (res < 0)
935 return res;
936
937 /* Update data segment pointers for all libraries */
938 for (i = 0; i < MAX_SHARED_LIBS; i++) {
939 if (!libinfo.lib_list[i].loaded)
940 continue;
941 for (j = 0; j < MAX_SHARED_LIBS; j++) {
942 unsigned long val = libinfo.lib_list[j].loaded ?
943 libinfo.lib_list[j].start_data : UNLOADED_LIB;
944 unsigned long __user *p = (unsigned long __user *)
945 libinfo.lib_list[i].start_data;
946 p -= j + 1;
947 if (put_user(val, p))
948 return -EFAULT;
949 }
950 }
951
952 install_exec_creds(bprm);
953
954 set_binfmt(&flat_format);
955
956 #ifdef CONFIG_MMU
957 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
958 if (!res)
959 res = create_flat_tables(bprm, bprm->p);
960 #else
961 /* Stash our initial stack pointer into the mm structure */
962 current->mm->start_stack =
963 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
964 pr_debug("sp=%lx\n", current->mm->start_stack);
965
966 /* copy the arg pages onto the stack */
967 res = transfer_args_to_stack(bprm, &current->mm->start_stack);
968 if (!res)
969 res = create_flat_tables(bprm, current->mm->start_stack);
970 #endif
971 if (res)
972 return res;
973
974 /* Fake some return addresses to ensure the call chain will
975 * initialise library in order for us. We are required to call
976 * lib 1 first, then 2, ... and finally the main program (id 0).
977 */
978 start_addr = libinfo.lib_list[0].entry;
979
980 #ifdef CONFIG_BINFMT_SHARED_FLAT
981 for (i = MAX_SHARED_LIBS-1; i > 0; i--) {
982 if (libinfo.lib_list[i].loaded) {
983 /* Push previos first to call address */
984 unsigned long __user *sp;
985 current->mm->start_stack -= sizeof(unsigned long);
986 sp = (unsigned long __user *)current->mm->start_stack;
987 __put_user(start_addr, sp);
988 start_addr = libinfo.lib_list[i].entry;
989 }
990 }
991 #endif
992
993 #ifdef FLAT_PLAT_INIT
994 FLAT_PLAT_INIT(regs);
995 #endif
996
997 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
998 regs, start_addr, current->mm->start_stack);
999 start_thread(regs, start_addr, current->mm->start_stack);
1000
1001 return 0;
1002 }
1003
1004 /****************************************************************************/
1005
1006 static int __init init_flat_binfmt(void)
1007 {
1008 register_binfmt(&flat_format);
1009 return 0;
1010 }
1011 core_initcall(init_flat_binfmt);
1012
1013 /****************************************************************************/
Linux kernel stable tree