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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 (dhowells@redhat.com)
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
40 typedef 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
51 MODULE_LICENSE("GPL");
52
53 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs);
54 //static int load_elf_fdpic_library(struct file *);
55 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file);
56 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
57 struct file *file,
58 struct mm_struct *mm,
59 const char *what);
60
61 static 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
67 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp);
68 static 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
73 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
74 struct file *file,
75 struct mm_struct *mm);
76
77 static 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
85 static int __init init_elf_fdpic_binfmt(void) { return register_binfmt(&elf_fdpic_format); }
86 static void __exit exit_elf_fdpic_binfmt(void) { unregister_binfmt(&elf_fdpic_format); }
87
88 module_init(init_elf_fdpic_binfmt)
89 module_exit(exit_elf_fdpic_binfmt)
90
91 static 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 */
108 static 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 */
150 static 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);
297
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
409 error:
410 if (interpreter) {
411 allow_write_access(interpreter);
412 fput(interpreter);
413 }
414 if (interpreter_name)
415 kfree(interpreter_name);
416 if (exec_params.phdrs)
417 kfree(exec_params.phdrs);
418 if (exec_params.loadmap)
419 kfree(exec_params.loadmap);
420 if (interp_params.phdrs)
421 kfree(interp_params.phdrs);
422 if (interp_params.loadmap)
423 kfree(interp_params.loadmap);
424 return retval;
425
426 /* unrecoverable error - kill the process */
427 error_kill:
428 send_sig(SIGSEGV, current, 0);
429 goto error;
430
431 } /* end load_elf_fdpic_binary() */
432
433 /*****************************************************************************/
434 /*
435 * present useful information to the program
436 */
437 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
438 struct mm_struct *mm,
439 struct elf_fdpic_params *exec_params,
440 struct elf_fdpic_params *interp_params)
441 {
442 unsigned long sp, csp, nitems;
443 elf_caddr_t *argv, *envp;
444 size_t platform_len = 0, len;
445 char *k_platform, *u_platform, *p;
446 long hwcap;
447 int loop;
448
449 /* we're going to shovel a whole load of stuff onto the stack */
450 #ifdef CONFIG_MMU
451 sp = bprm->p;
452 #else
453 sp = mm->start_stack;
454
455 /* stack the program arguments and environment */
456 if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
457 return -EFAULT;
458 #endif
459
460 /* get hold of platform and hardware capabilities masks for the machine
461 * we are running on. In some cases (Sparc), this info is impossible
462 * to get, in others (i386) it is merely difficult.
463 */
464 hwcap = ELF_HWCAP;
465 k_platform = ELF_PLATFORM;
466
467 if (k_platform) {
468 platform_len = strlen(k_platform) + 1;
469 sp -= platform_len;
470 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
471 return -EFAULT;
472 }
473
474 u_platform = (char *) sp;
475
476 #if defined(__i386__) && defined(CONFIG_SMP)
477 /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
478 * by the processes running on the same package. One thing we can do
479 * is to shuffle the initial stack for them.
480 *
481 * the conditionals here are unneeded, but kept in to make the
482 * code behaviour the same as pre change unless we have hyperthreaded
483 * processors. This keeps Mr Marcelo Person happier but should be
484 * removed for 2.5
485 */
486 if (smp_num_siblings > 1)
487 sp = sp - ((current->pid % 64) << 7);
488 #endif
489
490 sp &= ~7UL;
491
492 /* stack the load map(s) */
493 len = sizeof(struct elf32_fdpic_loadmap);
494 len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
495 sp = (sp - len) & ~7UL;
496 exec_params->map_addr = sp;
497
498 if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
499 return -EFAULT;
500
501 current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
502
503 if (interp_params->loadmap) {
504 len = sizeof(struct elf32_fdpic_loadmap);
505 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
506 sp = (sp - len) & ~7UL;
507 interp_params->map_addr = sp;
508
509 if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0)
510 return -EFAULT;
511
512 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
513 }
514
515 /* force 16 byte _final_ alignment here for generality */
516 #define DLINFO_ITEMS 13
517
518 nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
519 #ifdef DLINFO_ARCH_ITEMS
520 nitems += DLINFO_ARCH_ITEMS;
521 #endif
522
523 csp = sp;
524 sp -= nitems * 2 * sizeof(unsigned long);
525 sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */
526 sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */
527 sp -= 1 * sizeof(unsigned long); /* argc */
528
529 csp -= sp & 15UL;
530 sp -= sp & 15UL;
531
532 /* put the ELF interpreter info on the stack */
533 #define NEW_AUX_ENT(nr, id, val) \
534 do { \
535 struct { unsigned long _id, _val; } *ent = (void *) csp; \
536 __put_user((id), &ent[nr]._id); \
537 __put_user((val), &ent[nr]._val); \
538 } while (0)
539
540 csp -= 2 * sizeof(unsigned long);
541 NEW_AUX_ENT(0, AT_NULL, 0);
542 if (k_platform) {
543 csp -= 2 * sizeof(unsigned long);
544 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
545 }
546
547 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
548 NEW_AUX_ENT( 0, AT_HWCAP, hwcap);
549 NEW_AUX_ENT( 1, AT_PAGESZ, PAGE_SIZE);
550 NEW_AUX_ENT( 2, AT_CLKTCK, CLOCKS_PER_SEC);
551 NEW_AUX_ENT( 3, AT_PHDR, exec_params->ph_addr);
552 NEW_AUX_ENT( 4, AT_PHENT, sizeof(struct elf_phdr));
553 NEW_AUX_ENT( 5, AT_PHNUM, exec_params->hdr.e_phnum);
554 NEW_AUX_ENT( 6, AT_BASE, interp_params->elfhdr_addr);
555 NEW_AUX_ENT( 7, AT_FLAGS, 0);
556 NEW_AUX_ENT( 8, AT_ENTRY, exec_params->entry_addr);
557 NEW_AUX_ENT( 9, AT_UID, (elf_addr_t) current->uid);
558 NEW_AUX_ENT(10, AT_EUID, (elf_addr_t) current->euid);
559 NEW_AUX_ENT(11, AT_GID, (elf_addr_t) current->gid);
560 NEW_AUX_ENT(12, AT_EGID, (elf_addr_t) current->egid);
561
562 #ifdef ARCH_DLINFO
563 /* ARCH_DLINFO must come last so platform specific code can enforce
564 * special alignment requirements on the AUXV if necessary (eg. PPC).
565 */
566 ARCH_DLINFO;
567 #endif
568 #undef NEW_AUX_ENT
569
570 /* allocate room for argv[] and envv[] */
571 csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
572 envp = (elf_caddr_t *) csp;
573 csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
574 argv = (elf_caddr_t *) csp;
575
576 /* stack argc */
577 csp -= sizeof(unsigned long);
578 __put_user(bprm->argc, (unsigned long *) csp);
579
580 if (csp != sp)
581 BUG();
582
583 /* fill in the argv[] array */
584 #ifdef CONFIG_MMU
585 current->mm->arg_start = bprm->p;
586 #else
587 current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
588 #endif
589
590 p = (char *) current->mm->arg_start;
591 for (loop = bprm->argc; loop > 0; loop--) {
592 __put_user((elf_caddr_t) p, argv++);
593 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
594 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
595 return -EINVAL;
596 p += len;
597 }
598 __put_user(NULL, argv);
599 current->mm->arg_end = (unsigned long) p;
600
601 /* fill in the envv[] array */
602 current->mm->env_start = (unsigned long) p;
603 for (loop = bprm->envc; loop > 0; loop--) {
604 __put_user((elf_caddr_t)(unsigned long) p, envp++);
605 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
606 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
607 return -EINVAL;
608 p += len;
609 }
610 __put_user(NULL, envp);
611 current->mm->env_end = (unsigned long) p;
612
613 mm->start_stack = (unsigned long) sp;
614 return 0;
615 } /* end create_elf_fdpic_tables() */
616
617 /*****************************************************************************/
618 /*
619 * transfer the program arguments and environment from the holding pages onto
620 * the stack
621 */
622 #ifndef CONFIG_MMU
623 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
624 {
625 unsigned long index, stop, sp;
626 char *src;
627 int ret = 0;
628
629 stop = bprm->p >> PAGE_SHIFT;
630 sp = *_sp;
631
632 for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
633 src = kmap(bprm->page[index]);
634 sp -= PAGE_SIZE;
635 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
636 ret = -EFAULT;
637 kunmap(bprm->page[index]);
638 if (ret < 0)
639 goto out;
640 }
641
642 *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
643
644 out:
645 return ret;
646 } /* end elf_fdpic_transfer_args_to_stack() */
647 #endif
648
649 /*****************************************************************************/
650 /*
651 * load the appropriate binary image (executable or interpreter) into memory
652 * - we assume no MMU is available
653 * - if no other PIC bits are set in params->hdr->e_flags
654 * - we assume that the LOADable segments in the binary are independently relocatable
655 * - we assume R/O executable segments are shareable
656 * - else
657 * - we assume the loadable parts of the image to require fixed displacement
658 * - the image is not shareable
659 */
660 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
661 struct file *file,
662 struct mm_struct *mm,
663 const char *what)
664 {
665 struct elf32_fdpic_loadmap *loadmap;
666 #ifdef CONFIG_MMU
667 struct elf32_fdpic_loadseg *mseg;
668 #endif
669 struct elf32_fdpic_loadseg *seg;
670 struct elf32_phdr *phdr;
671 unsigned long load_addr, stop;
672 unsigned nloads, tmp;
673 size_t size;
674 int loop, ret;
675
676 /* allocate a load map table */
677 nloads = 0;
678 for (loop = 0; loop < params->hdr.e_phnum; loop++)
679 if (params->phdrs[loop].p_type == PT_LOAD)
680 nloads++;
681
682 if (nloads == 0)
683 return -ELIBBAD;
684
685 size = sizeof(*loadmap) + nloads * sizeof(*seg);
686 loadmap = kmalloc(size, GFP_KERNEL);
687 if (!loadmap)
688 return -ENOMEM;
689
690 params->loadmap = loadmap;
691 memset(loadmap, 0, size);
692
693 loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
694 loadmap->nsegs = nloads;
695
696 load_addr = params->load_addr;
697 seg = loadmap->segs;
698
699 /* map the requested LOADs into the memory space */
700 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
701 case ELF_FDPIC_FLAG_CONSTDISP:
702 case ELF_FDPIC_FLAG_CONTIGUOUS:
703 #ifndef CONFIG_MMU
704 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
705 if (ret < 0)
706 return ret;
707 break;
708 #endif
709 default:
710 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
711 if (ret < 0)
712 return ret;
713 break;
714 }
715
716 /* map the entry point */
717 if (params->hdr.e_entry) {
718 seg = loadmap->segs;
719 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
720 if (params->hdr.e_entry >= seg->p_vaddr &&
721 params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
722 ) {
723 params->entry_addr =
724 (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
725 break;
726 }
727 }
728 }
729
730 /* determine where the program header table has wound up if mapped */
731 stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
732 phdr = params->phdrs;
733
734 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
735 if (phdr->p_type != PT_LOAD)
736 continue;
737
738 if (phdr->p_offset > params->hdr.e_phoff ||
739 phdr->p_offset + phdr->p_filesz < stop)
740 continue;
741
742 seg = loadmap->segs;
743 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
744 if (phdr->p_vaddr >= seg->p_vaddr &&
745 phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
746 ) {
747 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
748 params->hdr.e_phoff - phdr->p_offset;
749 break;
750 }
751 }
752 break;
753 }
754
755 /* determine where the dynamic section has wound up if there is one */
756 phdr = params->phdrs;
757 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
758 if (phdr->p_type != PT_DYNAMIC)
759 continue;
760
761 seg = loadmap->segs;
762 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
763 if (phdr->p_vaddr >= seg->p_vaddr &&
764 phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
765 ) {
766 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
767
768 /* check the dynamic section contains at least one item, and that
769 * the last item is a NULL entry */
770 if (phdr->p_memsz == 0 ||
771 phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
772 goto dynamic_error;
773
774 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
775 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
776 goto dynamic_error;
777 break;
778 }
779 }
780 break;
781 }
782
783 /* now elide adjacent segments in the load map on MMU linux
784 * - on uClinux the holes between may actually be filled with system stuff or stuff from
785 * other processes
786 */
787 #ifdef CONFIG_MMU
788 nloads = loadmap->nsegs;
789 mseg = loadmap->segs;
790 seg = mseg + 1;
791 for (loop = 1; loop < nloads; loop++) {
792 /* see if we have a candidate for merging */
793 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
794 load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
795 if (load_addr == (seg->addr & PAGE_MASK)) {
796 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
797 mseg->p_memsz += seg->addr & ~PAGE_MASK;
798 mseg->p_memsz += seg->p_memsz;
799 loadmap->nsegs--;
800 continue;
801 }
802 }
803
804 mseg++;
805 if (mseg != seg)
806 *mseg = *seg;
807 }
808 #endif
809
810 kdebug("Mapped Object [%s]:", what);
811 kdebug("- elfhdr : %lx", params->elfhdr_addr);
812 kdebug("- entry : %lx", params->entry_addr);
813 kdebug("- PHDR[] : %lx", params->ph_addr);
814 kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
815 seg = loadmap->segs;
816 for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
817 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
818 loop,
819 seg->addr, seg->addr + seg->p_memsz - 1,
820 seg->p_vaddr, seg->p_memsz);
821
822 return 0;
823
824 dynamic_error:
825 printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
826 what, file->f_dentry->d_inode->i_ino);
827 return -ELIBBAD;
828 } /* end elf_fdpic_map_file() */
829
830 /*****************************************************************************/
831 /*
832 * map a file with constant displacement under uClinux
833 */
834 #ifndef CONFIG_MMU
835 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
836 struct file *file,
837 struct mm_struct *mm)
838 {
839 struct elf32_fdpic_loadseg *seg;
840 struct elf32_phdr *phdr;
841 unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
842 loff_t fpos;
843 int loop, ret;
844
845 load_addr = params->load_addr;
846 seg = params->loadmap->segs;
847
848 /* determine the bounds of the contiguous overall allocation we must make */
849 phdr = params->phdrs;
850 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
851 if (params->phdrs[loop].p_type != PT_LOAD)
852 continue;
853
854 if (base > phdr->p_vaddr)
855 base = phdr->p_vaddr;
856 if (top < phdr->p_vaddr + phdr->p_memsz)
857 top = phdr->p_vaddr + phdr->p_memsz;
858 }
859
860 /* allocate one big anon block for everything */
861 mflags = MAP_PRIVATE;
862 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
863 mflags |= MAP_EXECUTABLE;
864
865 down_write(&mm->mmap_sem);
866 maddr = do_mmap(NULL, load_addr, top - base,
867 PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
868 up_write(&mm->mmap_sem);
869 if (IS_ERR((void *) maddr))
870 return (int) maddr;
871
872 if (load_addr != 0)
873 load_addr += PAGE_ALIGN(top - base);
874
875 /* and then load the file segments into it */
876 phdr = params->phdrs;
877 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
878 if (params->phdrs[loop].p_type != PT_LOAD)
879 continue;
880
881 fpos = phdr->p_offset;
882
883 seg->addr = maddr + (phdr->p_vaddr - base);
884 seg->p_vaddr = phdr->p_vaddr;
885 seg->p_memsz = phdr->p_memsz;
886
887 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
888 if (ret < 0)
889 return ret;
890
891 /* map the ELF header address if in this segment */
892 if (phdr->p_offset == 0)
893 params->elfhdr_addr = seg->addr;
894
895 /* clear any space allocated but not loaded */
896 if (phdr->p_filesz < phdr->p_memsz)
897 clear_user((void *) (seg->addr + phdr->p_filesz),
898 phdr->p_memsz - phdr->p_filesz);
899
900 if (mm) {
901 if (phdr->p_flags & PF_X) {
902 mm->start_code = seg->addr;
903 mm->end_code = seg->addr + phdr->p_memsz;
904 }
905 else if (!mm->start_data) {
906 mm->start_data = seg->addr;
907 #ifndef CONFIG_MMU
908 mm->end_data = seg->addr + phdr->p_memsz;
909 #endif
910 }
911
912 #ifdef CONFIG_MMU
913 if (seg->addr + phdr->p_memsz > mm->end_data)
914 mm->end_data = seg->addr + phdr->p_memsz;
915 #endif
916 }
917
918 seg++;
919 }
920
921 return 0;
922 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */
923 #endif
924
925 /*****************************************************************************/
926 /*
927 * map a binary by direct mmap() of the individual PT_LOAD segments
928 */
929 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
930 struct file *file,
931 struct mm_struct *mm)
932 {
933 struct elf32_fdpic_loadseg *seg;
934 struct elf32_phdr *phdr;
935 unsigned long load_addr, delta_vaddr;
936 int loop, dvset;
937
938 load_addr = params->load_addr;
939 delta_vaddr = 0;
940 dvset = 0;
941
942 seg = params->loadmap->segs;
943
944 /* deal with each load segment separately */
945 phdr = params->phdrs;
946 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
947 unsigned long maddr, disp, excess, excess1;
948 int prot = 0, flags;
949
950 if (phdr->p_type != PT_LOAD)
951 continue;
952
953 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
954 (unsigned long) phdr->p_vaddr,
955 (unsigned long) phdr->p_offset,
956 (unsigned long) phdr->p_filesz,
957 (unsigned long) phdr->p_memsz);
958
959 /* determine the mapping parameters */
960 if (phdr->p_flags & PF_R) prot |= PROT_READ;
961 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
962 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
963
964 flags = MAP_PRIVATE | MAP_DENYWRITE;
965 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
966 flags |= MAP_EXECUTABLE;
967
968 maddr = 0;
969
970 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
971 case ELF_FDPIC_FLAG_INDEPENDENT:
972 /* PT_LOADs are independently locatable */
973 break;
974
975 case ELF_FDPIC_FLAG_HONOURVADDR:
976 /* the specified virtual address must be honoured */
977 maddr = phdr->p_vaddr;
978 flags |= MAP_FIXED;
979 break;
980
981 case ELF_FDPIC_FLAG_CONSTDISP:
982 /* constant displacement
983 * - can be mapped anywhere, but must be mapped as a unit
984 */
985 if (!dvset) {
986 maddr = load_addr;
987 delta_vaddr = phdr->p_vaddr;
988 dvset = 1;
989 }
990 else {
991 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
992 flags |= MAP_FIXED;
993 }
994 break;
995
996 case ELF_FDPIC_FLAG_CONTIGUOUS:
997 /* contiguity handled later */
998 break;
999
1000 default:
1001 BUG();
1002 }
1003
1004 maddr &= PAGE_MASK;
1005
1006 /* create the mapping */
1007 disp = phdr->p_vaddr & ~PAGE_MASK;
1008 down_write(&mm->mmap_sem);
1009 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1010 phdr->p_offset - disp);
1011 up_write(&mm->mmap_sem);
1012
1013 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1014 loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1015 maddr);
1016
1017 if (IS_ERR((void *) maddr))
1018 return (int) maddr;
1019
1020 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1021 load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1022
1023 seg->addr = maddr + disp;
1024 seg->p_vaddr = phdr->p_vaddr;
1025 seg->p_memsz = phdr->p_memsz;
1026
1027 /* map the ELF header address if in this segment */
1028 if (phdr->p_offset == 0)
1029 params->elfhdr_addr = seg->addr;
1030
1031 /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1032 if (prot & PROT_WRITE && disp > 0) {
1033 kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1034 clear_user((void *) maddr, disp);
1035 maddr += disp;
1036 }
1037
1038 /* clear any space allocated but not loaded
1039 * - on uClinux we can just clear the lot
1040 * - on MMU linux we'll get a SIGBUS beyond the last page
1041 * extant in the file
1042 */
1043 excess = phdr->p_memsz - phdr->p_filesz;
1044 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1045
1046 #ifdef CONFIG_MMU
1047
1048 if (excess > excess1) {
1049 unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1050 unsigned long xmaddr;
1051
1052 flags |= MAP_FIXED | MAP_ANONYMOUS;
1053 down_write(&mm->mmap_sem);
1054 xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1055 up_write(&mm->mmap_sem);
1056
1057 kdebug("mmap[%d] <anon>"
1058 " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1059 loop, xaddr, excess - excess1, prot, flags, xmaddr);
1060
1061 if (xmaddr != xaddr)
1062 return -ENOMEM;
1063 }
1064
1065 if (prot & PROT_WRITE && excess1 > 0) {
1066 kdebug("clear[%d] ad=%lx sz=%lx",
1067 loop, maddr + phdr->p_filesz, excess1);
1068 clear_user((void *) maddr + phdr->p_filesz, excess1);
1069 }
1070
1071 #else
1072 if (excess > 0) {
1073 kdebug("clear[%d] ad=%lx sz=%lx",
1074 loop, maddr + phdr->p_filesz, excess);
1075 clear_user((void *) maddr + phdr->p_filesz, excess);
1076 }
1077 #endif
1078
1079 if (mm) {
1080 if (phdr->p_flags & PF_X) {
1081 mm->start_code = maddr;
1082 mm->end_code = maddr + phdr->p_memsz;
1083 }
1084 else if (!mm->start_data) {
1085 mm->start_data = maddr;
1086 mm->end_data = maddr + phdr->p_memsz;
1087 }
1088 }
1089
1090 seg++;
1091 }
1092
1093 return 0;
1094 } /* end elf_fdpic_map_file_by_direct_mmap() */
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