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[PATCH] Decrease number of pointer derefs in multipath.c
[linux.git] / fs / binfmt_elf_fdpic.c
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1da177e4
LT		 1/* binfmt_elf_fdpic.c: FDPIC ELF binary format
2 *
3 * Copyright (C) 2003, 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells ([email protected])
5 * Derived from binfmt_elf.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/module.h>
14
15#include <linux/fs.h>
16#include <linux/stat.h>
17#include <linux/sched.h>
18#include <linux/mm.h>
19#include <linux/mman.h>
20#include <linux/errno.h>
21#include <linux/signal.h>
22#include <linux/binfmts.h>
23#include <linux/string.h>
24#include <linux/file.h>
25#include <linux/fcntl.h>
26#include <linux/slab.h>
27#include <linux/highmem.h>
28#include <linux/personality.h>
29#include <linux/ptrace.h>
30#include <linux/init.h>
31#include <linux/smp_lock.h>
32#include <linux/elf.h>
33#include <linux/elf-fdpic.h>
34#include <linux/elfcore.h>
35
36#include <asm/uaccess.h>
37#include <asm/param.h>
38#include <asm/pgalloc.h>
39
40typedef char *elf_caddr_t;
41#ifndef elf_addr_t
42#define elf_addr_t unsigned long
43#endif
44
45#if 0
46#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
47#else
48#define kdebug(fmt, ...) do {} while(0)
49#endif
50
51MODULE_LICENSE("GPL");
52
53static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs);
54//static int load_elf_fdpic_library(struct file *);
55static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file);
56static int elf_fdpic_map_file(struct elf_fdpic_params *params,
57 struct file *file,
58 struct mm_struct *mm,
59 const char *what);
60
61static int create_elf_fdpic_tables(struct linux_binprm *bprm,
62 struct mm_struct *mm,
63 struct elf_fdpic_params *exec_params,
64 struct elf_fdpic_params *interp_params);
65
66#ifndef CONFIG_MMU
67static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp);
68static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
69 struct file *file,
70 struct mm_struct *mm);
71#endif
72
73static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
74 struct file *file,
75 struct mm_struct *mm);
76
77static struct linux_binfmt elf_fdpic_format = {
78 .module = THIS_MODULE,
79 .load_binary = load_elf_fdpic_binary,
80// .load_shlib = load_elf_fdpic_library,
81// .core_dump = elf_fdpic_core_dump,
82 .min_coredump = ELF_EXEC_PAGESIZE,
83};
84
85static int __init init_elf_fdpic_binfmt(void) { return register_binfmt(&elf_fdpic_format); }
86static void __exit exit_elf_fdpic_binfmt(void) { unregister_binfmt(&elf_fdpic_format); }
87
88module_init(init_elf_fdpic_binfmt)
89module_exit(exit_elf_fdpic_binfmt)
90
91static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
92{
93 if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
94 return 0;
95 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
96 return 0;
97 if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
98 return 0;
99 if (!file->f_op || !file->f_op->mmap)
100 return 0;
101 return 1;
102}
103
104/*****************************************************************************/
105/*
106 * read the program headers table into memory
107 */
108static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file)
109{
110 struct elf32_phdr *phdr;
111 unsigned long size;
112 int retval, loop;
113
114 if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
115 return -ENOMEM;
116 if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
117 return -ENOMEM;
118
119 size = params->hdr.e_phnum * sizeof(struct elf_phdr);
120 params->phdrs = kmalloc(size, GFP_KERNEL);
121 if (!params->phdrs)
122 return -ENOMEM;
123
124 retval = kernel_read(file, params->hdr.e_phoff, (char *) params->phdrs, size);
125 if (retval < 0)
126 return retval;
127
128 /* determine stack size for this binary */
129 phdr = params->phdrs;
130 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
131 if (phdr->p_type != PT_GNU_STACK)
132 continue;
133
134 if (phdr->p_flags & PF_X)
135 params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
136 else
137 params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
138
139 params->stack_size = phdr->p_memsz;
140 break;
141 }
142
143 return 0;
144} /* end elf_fdpic_fetch_phdrs() */
145
146/*****************************************************************************/
147/*
148 * load an fdpic binary into various bits of memory
149 */
150static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs)
151{
152 struct elf_fdpic_params exec_params, interp_params;
153 struct elf_phdr *phdr;
154 unsigned long stack_size;
155 struct file *interpreter = NULL; /* to shut gcc up */
156 char *interpreter_name = NULL;
157 int executable_stack;
158 int retval, i;
159
160 memset(&exec_params, 0, sizeof(exec_params));
161 memset(&interp_params, 0, sizeof(interp_params));
162
163 exec_params.hdr = *(struct elfhdr *) bprm->buf;
164 exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
165
166 /* check that this is a binary we know how to deal with */
167 retval = -ENOEXEC;
168 if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
169 goto error;
170
171 /* read the program header table */
172 retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
173 if (retval < 0)
174 goto error;
175
176 /* scan for a program header that specifies an interpreter */
177 phdr = exec_params.phdrs;
178
179 for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
180 switch (phdr->p_type) {
181 case PT_INTERP:
182 retval = -ENOMEM;
183 if (phdr->p_filesz > PATH_MAX)
184 goto error;
185 retval = -ENOENT;
186 if (phdr->p_filesz < 2)
187 goto error;
188
189 /* read the name of the interpreter into memory */
190 interpreter_name = (char *) kmalloc(phdr->p_filesz, GFP_KERNEL);
191 if (!interpreter_name)
192 goto error;
193
194 retval = kernel_read(bprm->file,
195 phdr->p_offset,
196 interpreter_name,
197 phdr->p_filesz);
198 if (retval < 0)
199 goto error;
200
201 retval = -ENOENT;
202 if (interpreter_name[phdr->p_filesz - 1] != '\0')
203 goto error;
204
205 kdebug("Using ELF interpreter %s", interpreter_name);
206
207 /* replace the program with the interpreter */
208 interpreter = open_exec(interpreter_name);
209 retval = PTR_ERR(interpreter);
210 if (IS_ERR(interpreter)) {
211 interpreter = NULL;
212 goto error;
213 }
214
215 retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE);
216 if (retval < 0)
217 goto error;
218
219 interp_params.hdr = *((struct elfhdr *) bprm->buf);
220 break;
221
222 case PT_LOAD:
223#ifdef CONFIG_MMU
224 if (exec_params.load_addr == 0)
225 exec_params.load_addr = phdr->p_vaddr;
226#endif
227 break;
228 }
229
230 }
231
232 if (elf_check_const_displacement(&exec_params.hdr))
233 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
234
235 /* perform insanity checks on the interpreter */
236 if (interpreter_name) {
237 retval = -ELIBBAD;
238 if (!is_elf_fdpic(&interp_params.hdr, interpreter))
239 goto error;
240
241 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
242
243 /* read the interpreter's program header table */
244 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
245 if (retval < 0)
246 goto error;
247 }
248
249 stack_size = exec_params.stack_size;
250 if (stack_size < interp_params.stack_size)
251 stack_size = interp_params.stack_size;
252
253 if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
254 executable_stack = EXSTACK_ENABLE_X;
255 else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
256 executable_stack = EXSTACK_DISABLE_X;
257 else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
258 executable_stack = EXSTACK_ENABLE_X;
259 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
260 executable_stack = EXSTACK_DISABLE_X;
261 else
262 executable_stack = EXSTACK_DEFAULT;
263
264 retval = -ENOEXEC;
265 if (stack_size == 0)
266 goto error;
267
268 if (elf_check_const_displacement(&interp_params.hdr))
269 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
270
271 /* flush all traces of the currently running executable */
272 retval = flush_old_exec(bprm);
273 if (retval)
274 goto error;
275
276 /* there's now no turning back... the old userspace image is dead,
277 * defunct, deceased, etc. after this point we have to exit via
278 * error_kill */
279 set_personality(PER_LINUX_FDPIC);
280 set_binfmt(&elf_fdpic_format);
281
282 current->mm->start_code = 0;
283 current->mm->end_code = 0;
284 current->mm->start_stack = 0;
285 current->mm->start_data = 0;
286 current->mm->end_data = 0;
287 current->mm->context.exec_fdpic_loadmap = 0;
288 current->mm->context.interp_fdpic_loadmap = 0;
289
290 current->flags &= ~PF_FORKNOEXEC;
291
292#ifdef CONFIG_MMU
293 elf_fdpic_arch_lay_out_mm(&exec_params,
294 &interp_params,
295 &current->mm->start_stack,
296 &current->mm->start_brk);
1da177e4 297
1da177e4
LT		 298 retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack);
299 if (retval < 0) {
300 send_sig(SIGKILL, current, 0);
301 goto error_kill;
302 }
303#endif
304
305 /* load the executable and interpreter into memory */
306 retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable");
307 if (retval < 0)
308 goto error_kill;
309
310 if (interpreter_name) {
311 retval = elf_fdpic_map_file(&interp_params, interpreter,
312 current->mm, "interpreter");
313 if (retval < 0) {
314 printk(KERN_ERR "Unable to load interpreter\n");
315 goto error_kill;
316 }
317
318 allow_write_access(interpreter);
319 fput(interpreter);
320 interpreter = NULL;
321 }
322
323#ifdef CONFIG_MMU
324 if (!current->mm->start_brk)
325 current->mm->start_brk = current->mm->end_data;
326
327 current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk);
328
329#else
330 /* create a stack and brk area big enough for everyone
331 * - the brk heap starts at the bottom and works up
332 * - the stack starts at the top and works down
333 */
334 stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
335 if (stack_size < PAGE_SIZE * 2)
336 stack_size = PAGE_SIZE * 2;
337
338 down_write(&current->mm->mmap_sem);
339 current->mm->start_brk = do_mmap(NULL,
340 0,
341 stack_size,
342 PROT_READ | PROT_WRITE | PROT_EXEC,
343 MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
344 0);
345
346 if (IS_ERR((void *) current->mm->start_brk)) {
347 up_write(&current->mm->mmap_sem);
348 retval = current->mm->start_brk;
349 current->mm->start_brk = 0;
350 goto error_kill;
351 }
352
353 if (do_mremap(current->mm->start_brk,
354 stack_size,
355 ksize((char *) current->mm->start_brk),
356 0, 0
357 ) == current->mm->start_brk
358 )
359 stack_size = ksize((char *) current->mm->start_brk);
360 up_write(&current->mm->mmap_sem);
361
362 current->mm->brk = current->mm->start_brk;
363 current->mm->context.end_brk = current->mm->start_brk;
364 current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
365 current->mm->start_stack = current->mm->start_brk + stack_size;
366#endif
367
368 compute_creds(bprm);
369 current->flags &= ~PF_FORKNOEXEC;
370 if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0)
371 goto error_kill;
372
373 kdebug("- start_code %lx", (long) current->mm->start_code);
374 kdebug("- end_code %lx", (long) current->mm->end_code);
375 kdebug("- start_data %lx", (long) current->mm->start_data);
376 kdebug("- end_data %lx", (long) current->mm->end_data);
377 kdebug("- start_brk %lx", (long) current->mm->start_brk);
378 kdebug("- brk %lx", (long) current->mm->brk);
379 kdebug("- start_stack %lx", (long) current->mm->start_stack);
380
381#ifdef ELF_FDPIC_PLAT_INIT
382 /*
383 * The ABI may specify that certain registers be set up in special
384 * ways (on i386 %edx is the address of a DT_FINI function, for
385 * example. This macro performs whatever initialization to
386 * the regs structure is required.
387 */
388 ELF_FDPIC_PLAT_INIT(regs,
389 exec_params.map_addr,
390 interp_params.map_addr,
391 interp_params.dynamic_addr ?: exec_params.dynamic_addr
392 );
393#endif
394
395 /* everything is now ready... get the userspace context ready to roll */
396 start_thread(regs,
397 interp_params.entry_addr ?: exec_params.entry_addr,
398 current->mm->start_stack);
399
400 if (unlikely(current->ptrace & PT_PTRACED)) {
401 if (current->ptrace & PT_TRACE_EXEC)
402 ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
403 else
404 send_sig(SIGTRAP, current, 0);
405 }
406
407 retval = 0;
408
409error:
410 if (interpreter) {
411 allow_write_access(interpreter);
412 fput(interpreter);
413 }
f99d49ad
JJ		 414 kfree(interpreter_name);
415 kfree(exec_params.phdrs);
416 kfree(exec_params.loadmap);
417 kfree(interp_params.phdrs);
418 kfree(interp_params.loadmap);
1da177e4
LT		 419 return retval;
420
421 /* unrecoverable error - kill the process */
422 error_kill:
423 send_sig(SIGSEGV, current, 0);
424 goto error;
425
426} /* end load_elf_fdpic_binary() */
427
428/*****************************************************************************/
429/*
430 * present useful information to the program
431 */
432static int create_elf_fdpic_tables(struct linux_binprm *bprm,
433 struct mm_struct *mm,
434 struct elf_fdpic_params *exec_params,
435 struct elf_fdpic_params *interp_params)
436{
437 unsigned long sp, csp, nitems;
438 elf_caddr_t *argv, *envp;
439 size_t platform_len = 0, len;
440 char *k_platform, *u_platform, *p;
441 long hwcap;
442 int loop;
443
444 /* we're going to shovel a whole load of stuff onto the stack */
445#ifdef CONFIG_MMU
446 sp = bprm->p;
447#else
448 sp = mm->start_stack;
449
450 /* stack the program arguments and environment */
451 if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
452 return -EFAULT;
453#endif
454
455 /* get hold of platform and hardware capabilities masks for the machine
456 * we are running on. In some cases (Sparc), this info is impossible
457 * to get, in others (i386) it is merely difficult.
458 */
459 hwcap = ELF_HWCAP;
460 k_platform = ELF_PLATFORM;
461
462 if (k_platform) {
463 platform_len = strlen(k_platform) + 1;
464 sp -= platform_len;
465 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
466 return -EFAULT;
467 }
468
469 u_platform = (char *) sp;
470
471#if defined(__i386__) && defined(CONFIG_SMP)
472 /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
473 * by the processes running on the same package. One thing we can do
474 * is to shuffle the initial stack for them.
475 *
476 * the conditionals here are unneeded, but kept in to make the
477 * code behaviour the same as pre change unless we have hyperthreaded
478 * processors. This keeps Mr Marcelo Person happier but should be
479 * removed for 2.5
480 */
481 if (smp_num_siblings > 1)
482 sp = sp - ((current->pid % 64) << 7);
483#endif
484
485 sp &= ~7UL;
486
487 /* stack the load map(s) */
488 len = sizeof(struct elf32_fdpic_loadmap);
489 len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
490 sp = (sp - len) & ~7UL;
491 exec_params->map_addr = sp;
492
493 if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
494 return -EFAULT;
495
496 current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
497
498 if (interp_params->loadmap) {
499 len = sizeof(struct elf32_fdpic_loadmap);
500 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
501 sp = (sp - len) & ~7UL;
502 interp_params->map_addr = sp;
503
504 if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0)
505 return -EFAULT;
506
507 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
508 }
509
510 /* force 16 byte _final_ alignment here for generality */
511#define DLINFO_ITEMS 13
512
513 nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
514#ifdef DLINFO_ARCH_ITEMS
515 nitems += DLINFO_ARCH_ITEMS;
516#endif
517
518 csp = sp;
519 sp -= nitems * 2 * sizeof(unsigned long);
520 sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */
521 sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */
522 sp -= 1 * sizeof(unsigned long); /* argc */
523
524 csp -= sp & 15UL;
525 sp -= sp & 15UL;
526
527 /* put the ELF interpreter info on the stack */
528#define NEW_AUX_ENT(nr, id, val) \
529 do { \
530 struct { unsigned long _id, _val; } *ent = (void *) csp; \
531 __put_user((id), &ent[nr]._id); \
532 __put_user((val), &ent[nr]._val); \
533 } while (0)
534
535 csp -= 2 * sizeof(unsigned long);
536 NEW_AUX_ENT(0, AT_NULL, 0);
537 if (k_platform) {
538 csp -= 2 * sizeof(unsigned long);
539 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
540 }
541
542 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
543 NEW_AUX_ENT( 0, AT_HWCAP, hwcap);
544 NEW_AUX_ENT( 1, AT_PAGESZ, PAGE_SIZE);
545 NEW_AUX_ENT( 2, AT_CLKTCK, CLOCKS_PER_SEC);
546 NEW_AUX_ENT( 3, AT_PHDR, exec_params->ph_addr);
547 NEW_AUX_ENT( 4, AT_PHENT, sizeof(struct elf_phdr));
548 NEW_AUX_ENT( 5, AT_PHNUM, exec_params->hdr.e_phnum);
549 NEW_AUX_ENT( 6, AT_BASE, interp_params->elfhdr_addr);
550 NEW_AUX_ENT( 7, AT_FLAGS, 0);
551 NEW_AUX_ENT( 8, AT_ENTRY, exec_params->entry_addr);
552 NEW_AUX_ENT( 9, AT_UID, (elf_addr_t) current->uid);
553 NEW_AUX_ENT(10, AT_EUID, (elf_addr_t) current->euid);
554 NEW_AUX_ENT(11, AT_GID, (elf_addr_t) current->gid);
555 NEW_AUX_ENT(12, AT_EGID, (elf_addr_t) current->egid);
556
557#ifdef ARCH_DLINFO
558 /* ARCH_DLINFO must come last so platform specific code can enforce
559 * special alignment requirements on the AUXV if necessary (eg. PPC).
560 */
561 ARCH_DLINFO;
562#endif
563#undef NEW_AUX_ENT
564
565 /* allocate room for argv[] and envv[] */
566 csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
567 envp = (elf_caddr_t *) csp;
568 csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
569 argv = (elf_caddr_t *) csp;
570
571 /* stack argc */
572 csp -= sizeof(unsigned long);
573 __put_user(bprm->argc, (unsigned long *) csp);
574
575 if (csp != sp)
576 BUG();
577
578 /* fill in the argv[] array */
579#ifdef CONFIG_MMU
580 current->mm->arg_start = bprm->p;
581#else
582 current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
583#endif
584
585 p = (char *) current->mm->arg_start;
586 for (loop = bprm->argc; loop > 0; loop--) {
587 __put_user((elf_caddr_t) p, argv++);
588 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
589 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
590 return -EINVAL;
591 p += len;
592 }
593 __put_user(NULL, argv);
594 current->mm->arg_end = (unsigned long) p;
595
596 /* fill in the envv[] array */
597 current->mm->env_start = (unsigned long) p;
598 for (loop = bprm->envc; loop > 0; loop--) {
599 __put_user((elf_caddr_t)(unsigned long) p, envp++);
600 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
601 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
602 return -EINVAL;
603 p += len;
604 }
605 __put_user(NULL, envp);
606 current->mm->env_end = (unsigned long) p;
607
608 mm->start_stack = (unsigned long) sp;
609 return 0;
610} /* end create_elf_fdpic_tables() */
611
612/*****************************************************************************/
613/*
614 * transfer the program arguments and environment from the holding pages onto
615 * the stack
616 */
617#ifndef CONFIG_MMU
618static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
619{
620 unsigned long index, stop, sp;
621 char *src;
622 int ret = 0;
623
624 stop = bprm->p >> PAGE_SHIFT;
625 sp = *_sp;
626
627 for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
628 src = kmap(bprm->page[index]);
629 sp -= PAGE_SIZE;
630 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
631 ret = -EFAULT;
632 kunmap(bprm->page[index]);
633 if (ret < 0)
634 goto out;
635 }
636
637 *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
638
639 out:
640 return ret;
641} /* end elf_fdpic_transfer_args_to_stack() */
642#endif
643
644/*****************************************************************************/
645/*
646 * load the appropriate binary image (executable or interpreter) into memory
647 * - we assume no MMU is available
648 * - if no other PIC bits are set in params->hdr->e_flags
649 * - we assume that the LOADable segments in the binary are independently relocatable
650 * - we assume R/O executable segments are shareable
651 * - else
652 * - we assume the loadable parts of the image to require fixed displacement
653 * - the image is not shareable
654 */
655static int elf_fdpic_map_file(struct elf_fdpic_params *params,
656 struct file *file,
657 struct mm_struct *mm,
658 const char *what)
659{
660 struct elf32_fdpic_loadmap *loadmap;
661#ifdef CONFIG_MMU
662 struct elf32_fdpic_loadseg *mseg;
663#endif
664 struct elf32_fdpic_loadseg *seg;
665 struct elf32_phdr *phdr;
666 unsigned long load_addr, stop;
667 unsigned nloads, tmp;
668 size_t size;
669 int loop, ret;
670
671 /* allocate a load map table */
672 nloads = 0;
673 for (loop = 0; loop < params->hdr.e_phnum; loop++)
674 if (params->phdrs[loop].p_type == PT_LOAD)
675 nloads++;
676
677 if (nloads == 0)
678 return -ELIBBAD;
679
680 size = sizeof(*loadmap) + nloads * sizeof(*seg);
681 loadmap = kmalloc(size, GFP_KERNEL);
682 if (!loadmap)
683 return -ENOMEM;
684
685 params->loadmap = loadmap;
686 memset(loadmap, 0, size);
687
688 loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
689 loadmap->nsegs = nloads;
690
691 load_addr = params->load_addr;
692 seg = loadmap->segs;
693
694 /* map the requested LOADs into the memory space */
695 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
696 case ELF_FDPIC_FLAG_CONSTDISP:
697 case ELF_FDPIC_FLAG_CONTIGUOUS:
698#ifndef CONFIG_MMU
699 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
700 if (ret < 0)
701 return ret;
702 break;
703#endif
704 default:
705 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
706 if (ret < 0)
707 return ret;
708 break;
709 }
710
711 /* map the entry point */
712 if (params->hdr.e_entry) {
713 seg = loadmap->segs;
714 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
715 if (params->hdr.e_entry >= seg->p_vaddr &&
716 params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
717 ) {
718 params->entry_addr =
719 (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
720 break;
721 }
722 }
723 }
724
725 /* determine where the program header table has wound up if mapped */
726 stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
727 phdr = params->phdrs;
728
729 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
730 if (phdr->p_type != PT_LOAD)
731 continue;
732
733 if (phdr->p_offset > params->hdr.e_phoff ||
734 phdr->p_offset + phdr->p_filesz < stop)
735 continue;
736
737 seg = loadmap->segs;
738 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
739 if (phdr->p_vaddr >= seg->p_vaddr &&
740 phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
741 ) {
742 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
743 params->hdr.e_phoff - phdr->p_offset;
744 break;
745 }
746 }
747 break;
748 }
749
750 /* determine where the dynamic section has wound up if there is one */
751 phdr = params->phdrs;
752 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
753 if (phdr->p_type != PT_DYNAMIC)
754 continue;
755
756 seg = loadmap->segs;
757 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
758 if (phdr->p_vaddr >= seg->p_vaddr &&
759 phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
760 ) {
761 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
762
763 /* check the dynamic section contains at least one item, and that
764 * the last item is a NULL entry */
765 if (phdr->p_memsz == 0 ||
766 phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
767 goto dynamic_error;
768
769 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
770 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
771 goto dynamic_error;
772 break;
773 }
774 }
775 break;
776 }
777
778 /* now elide adjacent segments in the load map on MMU linux
779 * - on uClinux the holes between may actually be filled with system stuff or stuff from
780 * other processes
781 */
782#ifdef CONFIG_MMU
783 nloads = loadmap->nsegs;
784 mseg = loadmap->segs;
785 seg = mseg + 1;
786 for (loop = 1; loop < nloads; loop++) {
787 /* see if we have a candidate for merging */
788 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
789 load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
790 if (load_addr == (seg->addr & PAGE_MASK)) {
791 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
792 mseg->p_memsz += seg->addr & ~PAGE_MASK;
793 mseg->p_memsz += seg->p_memsz;
794 loadmap->nsegs--;
795 continue;
796 }
797 }
798
799 mseg++;
800 if (mseg != seg)
801 *mseg = *seg;
802 }
803#endif
804
805 kdebug("Mapped Object [%s]:", what);
806 kdebug("- elfhdr : %lx", params->elfhdr_addr);
807 kdebug("- entry : %lx", params->entry_addr);
808 kdebug("- PHDR[] : %lx", params->ph_addr);
809 kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
810 seg = loadmap->segs;
811 for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
812 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
813 loop,
814 seg->addr, seg->addr + seg->p_memsz - 1,
815 seg->p_vaddr, seg->p_memsz);
816
817 return 0;
818
819 dynamic_error:
820 printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
821 what, file->f_dentry->d_inode->i_ino);
822 return -ELIBBAD;
823} /* end elf_fdpic_map_file() */
824
825/*****************************************************************************/
826/*
827 * map a file with constant displacement under uClinux
828 */
829#ifndef CONFIG_MMU
830static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
831 struct file *file,
832 struct mm_struct *mm)
833{
834 struct elf32_fdpic_loadseg *seg;
835 struct elf32_phdr *phdr;
836 unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
837 loff_t fpos;
838 int loop, ret;
839
840 load_addr = params->load_addr;
841 seg = params->loadmap->segs;
842
843 /* determine the bounds of the contiguous overall allocation we must make */
844 phdr = params->phdrs;
845 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
846 if (params->phdrs[loop].p_type != PT_LOAD)
847 continue;
848
849 if (base > phdr->p_vaddr)
850 base = phdr->p_vaddr;
851 if (top < phdr->p_vaddr + phdr->p_memsz)
852 top = phdr->p_vaddr + phdr->p_memsz;
853 }
854
855 /* allocate one big anon block for everything */
856 mflags = MAP_PRIVATE;
857 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
858 mflags |= MAP_EXECUTABLE;
859
860 down_write(&mm->mmap_sem);
861 maddr = do_mmap(NULL, load_addr, top - base,
862 PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
863 up_write(&mm->mmap_sem);
864 if (IS_ERR((void *) maddr))
865 return (int) maddr;
866
867 if (load_addr != 0)
868 load_addr += PAGE_ALIGN(top - base);
869
870 /* and then load the file segments into it */
871 phdr = params->phdrs;
872 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
873 if (params->phdrs[loop].p_type != PT_LOAD)
874 continue;
875
876 fpos = phdr->p_offset;
877
878 seg->addr = maddr + (phdr->p_vaddr - base);
879 seg->p_vaddr = phdr->p_vaddr;
880 seg->p_memsz = phdr->p_memsz;
881
882 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
883 if (ret < 0)
884 return ret;
885
886 /* map the ELF header address if in this segment */
887 if (phdr->p_offset == 0)
888 params->elfhdr_addr = seg->addr;
889
890 /* clear any space allocated but not loaded */
891 if (phdr->p_filesz < phdr->p_memsz)
892 clear_user((void *) (seg->addr + phdr->p_filesz),
893 phdr->p_memsz - phdr->p_filesz);
894
895 if (mm) {
896 if (phdr->p_flags & PF_X) {
897 mm->start_code = seg->addr;
898 mm->end_code = seg->addr + phdr->p_memsz;
899 }
900 else if (!mm->start_data) {
901 mm->start_data = seg->addr;
902#ifndef CONFIG_MMU
903 mm->end_data = seg->addr + phdr->p_memsz;
904#endif
905 }
906
907#ifdef CONFIG_MMU
908 if (seg->addr + phdr->p_memsz > mm->end_data)
909 mm->end_data = seg->addr + phdr->p_memsz;
910#endif
911 }
912
913 seg++;
914 }
915
916 return 0;
917} /* end elf_fdpic_map_file_constdisp_on_uclinux() */
918#endif
919
920/*****************************************************************************/
921/*
922 * map a binary by direct mmap() of the individual PT_LOAD segments
923 */
924static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
925 struct file *file,
926 struct mm_struct *mm)
927{
928 struct elf32_fdpic_loadseg *seg;
929 struct elf32_phdr *phdr;
930 unsigned long load_addr, delta_vaddr;
931 int loop, dvset;
932
933 load_addr = params->load_addr;
934 delta_vaddr = 0;
935 dvset = 0;
936
937 seg = params->loadmap->segs;
938
939 /* deal with each load segment separately */
940 phdr = params->phdrs;
941 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
942 unsigned long maddr, disp, excess, excess1;
943 int prot = 0, flags;
944
945 if (phdr->p_type != PT_LOAD)
946 continue;
947
948 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
949 (unsigned long) phdr->p_vaddr,
950 (unsigned long) phdr->p_offset,
951 (unsigned long) phdr->p_filesz,
952 (unsigned long) phdr->p_memsz);
953
954 /* determine the mapping parameters */
955 if (phdr->p_flags & PF_R) prot |= PROT_READ;
956 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
957 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
958
959 flags = MAP_PRIVATE | MAP_DENYWRITE;
960 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
961 flags |= MAP_EXECUTABLE;
962
963 maddr = 0;
964
965 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
966 case ELF_FDPIC_FLAG_INDEPENDENT:
967 /* PT_LOADs are independently locatable */
968 break;
969
970 case ELF_FDPIC_FLAG_HONOURVADDR:
971 /* the specified virtual address must be honoured */
972 maddr = phdr->p_vaddr;
973 flags |= MAP_FIXED;
974 break;
975
976 case ELF_FDPIC_FLAG_CONSTDISP:
977 /* constant displacement
978 * - can be mapped anywhere, but must be mapped as a unit
979 */
980 if (!dvset) {
981 maddr = load_addr;
982 delta_vaddr = phdr->p_vaddr;
983 dvset = 1;
984 }
985 else {
986 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
987 flags |= MAP_FIXED;
988 }
989 break;
990
991 case ELF_FDPIC_FLAG_CONTIGUOUS:
992 /* contiguity handled later */
993 break;
994
995 default:
996 BUG();
997 }
998
999 maddr &= PAGE_MASK;
1000
1001 /* create the mapping */
1002 disp = phdr->p_vaddr & ~PAGE_MASK;
1003 down_write(&mm->mmap_sem);
1004 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1005 phdr->p_offset - disp);
1006 up_write(&mm->mmap_sem);
1007
1008 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1009 loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1010 maddr);
1011
1012 if (IS_ERR((void *) maddr))
1013 return (int) maddr;
1014
1015 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1016 load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1017
1018 seg->addr = maddr + disp;
1019 seg->p_vaddr = phdr->p_vaddr;
1020 seg->p_memsz = phdr->p_memsz;
1021
1022 /* map the ELF header address if in this segment */
1023 if (phdr->p_offset == 0)
1024 params->elfhdr_addr = seg->addr;
1025
1026 /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1027 if (prot & PROT_WRITE && disp > 0) {
1028 kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1029 clear_user((void *) maddr, disp);
1030 maddr += disp;
1031 }
1032
1033 /* clear any space allocated but not loaded
1034 * - on uClinux we can just clear the lot
1035 * - on MMU linux we'll get a SIGBUS beyond the last page
1036 * extant in the file
1037 */
1038 excess = phdr->p_memsz - phdr->p_filesz;
1039 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1040
1041#ifdef CONFIG_MMU
1042
1043 if (excess > excess1) {
1044 unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1045 unsigned long xmaddr;
1046
1047 flags |= MAP_FIXED | MAP_ANONYMOUS;
1048 down_write(&mm->mmap_sem);
1049 xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1050 up_write(&mm->mmap_sem);
1051
1052 kdebug("mmap[%d] <anon>"
1053 " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1054 loop, xaddr, excess - excess1, prot, flags, xmaddr);
1055
1056 if (xmaddr != xaddr)
1057 return -ENOMEM;
1058 }
1059
1060 if (prot & PROT_WRITE && excess1 > 0) {
1061 kdebug("clear[%d] ad=%lx sz=%lx",
1062 loop, maddr + phdr->p_filesz, excess1);
1063 clear_user((void *) maddr + phdr->p_filesz, excess1);
1064 }
1065
1066#else
1067 if (excess > 0) {
1068 kdebug("clear[%d] ad=%lx sz=%lx",
1069 loop, maddr + phdr->p_filesz, excess);
1070 clear_user((void *) maddr + phdr->p_filesz, excess);
1071 }
1072#endif
1073
1074 if (mm) {
1075 if (phdr->p_flags & PF_X) {
1076 mm->start_code = maddr;
1077 mm->end_code = maddr + phdr->p_memsz;
1078 }
1079 else if (!mm->start_data) {
1080 mm->start_data = maddr;
1081 mm->end_data = maddr + phdr->p_memsz;
1082 }
1083 }
1084
1085 seg++;
1086 }
1087
1088 return 0;
1089} /* end elf_fdpic_map_file_by_direct_mmap() */
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