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[PATCH] Remove f_error field from struct file
[wrt350n-kernel.git] / fs / binfmt_elf_fdpic.c
blob134c9c0d1f54f6128e55da8b14d17d69a76080dc
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 #endif
298
299 /* do this so that we can load the interpreter, if need be
300 * - we will change some of these later
301 */
302 set_mm_counter(current->mm, rss, 0);
303
304 #ifdef CONFIG_MMU
305 retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack);
306 if (retval < 0) {
307 send_sig(SIGKILL, current, 0);
308 goto error_kill;
309 }
310 #endif
311
312 /* load the executable and interpreter into memory */
313 retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable");
314 if (retval < 0)
315 goto error_kill;
316
317 if (interpreter_name) {
318 retval = elf_fdpic_map_file(&interp_params, interpreter,
319 current->mm, "interpreter");
320 if (retval < 0) {
321 printk(KERN_ERR "Unable to load interpreter\n");
322 goto error_kill;
323 }
324
325 allow_write_access(interpreter);
326 fput(interpreter);
327 interpreter = NULL;
328 }
329
330 #ifdef CONFIG_MMU
331 if (!current->mm->start_brk)
332 current->mm->start_brk = current->mm->end_data;
333
334 current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk);
335
336 #else
337 /* create a stack and brk area big enough for everyone
338 * - the brk heap starts at the bottom and works up
339 * - the stack starts at the top and works down
340 */
341 stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
342 if (stack_size < PAGE_SIZE * 2)
343 stack_size = PAGE_SIZE * 2;
344
345 down_write(&current->mm->mmap_sem);
346 current->mm->start_brk = do_mmap(NULL,
347 0,
348 stack_size,
349 PROT_READ | PROT_WRITE | PROT_EXEC,
350 MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
351 0);
352
353 if (IS_ERR((void *) current->mm->start_brk)) {
354 up_write(&current->mm->mmap_sem);
355 retval = current->mm->start_brk;
356 current->mm->start_brk = 0;
357 goto error_kill;
358 }
359
360 if (do_mremap(current->mm->start_brk,
361 stack_size,
362 ksize((char *) current->mm->start_brk),
363 0, 0
364 ) == current->mm->start_brk
365 )
366 stack_size = ksize((char *) current->mm->start_brk);
367 up_write(&current->mm->mmap_sem);
368
369 current->mm->brk = current->mm->start_brk;
370 current->mm->context.end_brk = current->mm->start_brk;
371 current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
372 current->mm->start_stack = current->mm->start_brk + stack_size;
373 #endif
374
375 compute_creds(bprm);
376 current->flags &= ~PF_FORKNOEXEC;
377 if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0)
378 goto error_kill;
379
380 kdebug("- start_code %lx", (long) current->mm->start_code);
381 kdebug("- end_code %lx", (long) current->mm->end_code);
382 kdebug("- start_data %lx", (long) current->mm->start_data);
383 kdebug("- end_data %lx", (long) current->mm->end_data);
384 kdebug("- start_brk %lx", (long) current->mm->start_brk);
385 kdebug("- brk %lx", (long) current->mm->brk);
386 kdebug("- start_stack %lx", (long) current->mm->start_stack);
387
388 #ifdef ELF_FDPIC_PLAT_INIT
389 /*
390 * The ABI may specify that certain registers be set up in special
391 * ways (on i386 %edx is the address of a DT_FINI function, for
392 * example. This macro performs whatever initialization to
393 * the regs structure is required.
394 */
395 ELF_FDPIC_PLAT_INIT(regs,
396 exec_params.map_addr,
397 interp_params.map_addr,
398 interp_params.dynamic_addr ?: exec_params.dynamic_addr
399 );
400 #endif
401
402 /* everything is now ready... get the userspace context ready to roll */
403 start_thread(regs,
404 interp_params.entry_addr ?: exec_params.entry_addr,
405 current->mm->start_stack);
406
407 if (unlikely(current->ptrace & PT_PTRACED)) {
408 if (current->ptrace & PT_TRACE_EXEC)
409 ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
410 else
411 send_sig(SIGTRAP, current, 0);
412 }
413
414 retval = 0;
415
416 error:
417 if (interpreter) {
418 allow_write_access(interpreter);
419 fput(interpreter);
420 }
421 if (interpreter_name)
422 kfree(interpreter_name);
423 if (exec_params.phdrs)
424 kfree(exec_params.phdrs);
425 if (exec_params.loadmap)
426 kfree(exec_params.loadmap);
427 if (interp_params.phdrs)
428 kfree(interp_params.phdrs);
429 if (interp_params.loadmap)
430 kfree(interp_params.loadmap);
431 return retval;
432
433 /* unrecoverable error - kill the process */
434 error_kill:
435 send_sig(SIGSEGV, current, 0);
436 goto error;
437
438 } /* end load_elf_fdpic_binary() */
439
440 /*****************************************************************************/
441 /*
442 * present useful information to the program
443 */
444 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
445 struct mm_struct *mm,
446 struct elf_fdpic_params *exec_params,
447 struct elf_fdpic_params *interp_params)
448 {
449 unsigned long sp, csp, nitems;
450 elf_caddr_t *argv, *envp;
451 size_t platform_len = 0, len;
452 char *k_platform, *u_platform, *p;
453 long hwcap;
454 int loop;
455
456 /* we're going to shovel a whole load of stuff onto the stack */
457 #ifdef CONFIG_MMU
458 sp = bprm->p;
459 #else
460 sp = mm->start_stack;
461
462 /* stack the program arguments and environment */
463 if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
464 return -EFAULT;
465 #endif
466
467 /* get hold of platform and hardware capabilities masks for the machine
468 * we are running on. In some cases (Sparc), this info is impossible
469 * to get, in others (i386) it is merely difficult.
470 */
471 hwcap = ELF_HWCAP;
472 k_platform = ELF_PLATFORM;
473
474 if (k_platform) {
475 platform_len = strlen(k_platform) + 1;
476 sp -= platform_len;
477 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
478 return -EFAULT;
479 }
480
481 u_platform = (char *) sp;
482
483 #if defined(__i386__) && defined(CONFIG_SMP)
484 /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
485 * by the processes running on the same package. One thing we can do
486 * is to shuffle the initial stack for them.
487 *
488 * the conditionals here are unneeded, but kept in to make the
489 * code behaviour the same as pre change unless we have hyperthreaded
490 * processors. This keeps Mr Marcelo Person happier but should be
491 * removed for 2.5
492 */
493 if (smp_num_siblings > 1)
494 sp = sp - ((current->pid % 64) << 7);
495 #endif
496
497 sp &= ~7UL;
498
499 /* stack the load map(s) */
500 len = sizeof(struct elf32_fdpic_loadmap);
501 len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
502 sp = (sp - len) & ~7UL;
503 exec_params->map_addr = sp;
504
505 if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
506 return -EFAULT;
507
508 current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
509
510 if (interp_params->loadmap) {
511 len = sizeof(struct elf32_fdpic_loadmap);
512 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
513 sp = (sp - len) & ~7UL;
514 interp_params->map_addr = sp;
515
516 if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0)
517 return -EFAULT;
518
519 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
520 }
521
522 /* force 16 byte _final_ alignment here for generality */
523 #define DLINFO_ITEMS 13
524
525 nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
526 #ifdef DLINFO_ARCH_ITEMS
527 nitems += DLINFO_ARCH_ITEMS;
528 #endif
529
530 csp = sp;
531 sp -= nitems * 2 * sizeof(unsigned long);
532 sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */
533 sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */
534 sp -= 1 * sizeof(unsigned long); /* argc */
535
536 csp -= sp & 15UL;
537 sp -= sp & 15UL;
538
539 /* put the ELF interpreter info on the stack */
540 #define NEW_AUX_ENT(nr, id, val) \
541 do { \
542 struct { unsigned long _id, _val; } *ent = (void *) csp; \
543 __put_user((id), &ent[nr]._id); \
544 __put_user((val), &ent[nr]._val); \
545 } while (0)
546
547 csp -= 2 * sizeof(unsigned long);
548 NEW_AUX_ENT(0, AT_NULL, 0);
549 if (k_platform) {
550 csp -= 2 * sizeof(unsigned long);
551 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
552 }
553
554 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
555 NEW_AUX_ENT( 0, AT_HWCAP, hwcap);
556 NEW_AUX_ENT( 1, AT_PAGESZ, PAGE_SIZE);
557 NEW_AUX_ENT( 2, AT_CLKTCK, CLOCKS_PER_SEC);
558 NEW_AUX_ENT( 3, AT_PHDR, exec_params->ph_addr);
559 NEW_AUX_ENT( 4, AT_PHENT, sizeof(struct elf_phdr));
560 NEW_AUX_ENT( 5, AT_PHNUM, exec_params->hdr.e_phnum);
561 NEW_AUX_ENT( 6, AT_BASE, interp_params->elfhdr_addr);
562 NEW_AUX_ENT( 7, AT_FLAGS, 0);
563 NEW_AUX_ENT( 8, AT_ENTRY, exec_params->entry_addr);
564 NEW_AUX_ENT( 9, AT_UID, (elf_addr_t) current->uid);
565 NEW_AUX_ENT(10, AT_EUID, (elf_addr_t) current->euid);
566 NEW_AUX_ENT(11, AT_GID, (elf_addr_t) current->gid);
567 NEW_AUX_ENT(12, AT_EGID, (elf_addr_t) current->egid);
568
569 #ifdef ARCH_DLINFO
570 /* ARCH_DLINFO must come last so platform specific code can enforce
571 * special alignment requirements on the AUXV if necessary (eg. PPC).
572 */
573 ARCH_DLINFO;
574 #endif
575 #undef NEW_AUX_ENT
576
577 /* allocate room for argv[] and envv[] */
578 csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
579 envp = (elf_caddr_t *) csp;
580 csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
581 argv = (elf_caddr_t *) csp;
582
583 /* stack argc */
584 csp -= sizeof(unsigned long);
585 __put_user(bprm->argc, (unsigned long *) csp);
586
587 if (csp != sp)
588 BUG();
589
590 /* fill in the argv[] array */
591 #ifdef CONFIG_MMU
592 current->mm->arg_start = bprm->p;
593 #else
594 current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
595 #endif
596
597 p = (char *) current->mm->arg_start;
598 for (loop = bprm->argc; loop > 0; loop--) {
599 __put_user((elf_caddr_t) p, argv++);
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, argv);
606 current->mm->arg_end = (unsigned long) p;
607
608 /* fill in the envv[] array */
609 current->mm->env_start = (unsigned long) p;
610 for (loop = bprm->envc; loop > 0; loop--) {
611 __put_user((elf_caddr_t)(unsigned long) p, envp++);
612 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
613 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
614 return -EINVAL;
615 p += len;
616 }
617 __put_user(NULL, envp);
618 current->mm->env_end = (unsigned long) p;
619
620 mm->start_stack = (unsigned long) sp;
621 return 0;
622 } /* end create_elf_fdpic_tables() */
623
624 /*****************************************************************************/
625 /*
626 * transfer the program arguments and environment from the holding pages onto
627 * the stack
628 */
629 #ifndef CONFIG_MMU
630 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
631 {
632 unsigned long index, stop, sp;
633 char *src;
634 int ret = 0;
635
636 stop = bprm->p >> PAGE_SHIFT;
637 sp = *_sp;
638
639 for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
640 src = kmap(bprm->page[index]);
641 sp -= PAGE_SIZE;
642 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
643 ret = -EFAULT;
644 kunmap(bprm->page[index]);
645 if (ret < 0)
646 goto out;
647 }
648
649 *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
650
651 out:
652 return ret;
653 } /* end elf_fdpic_transfer_args_to_stack() */
654 #endif
655
656 /*****************************************************************************/
657 /*
658 * load the appropriate binary image (executable or interpreter) into memory
659 * - we assume no MMU is available
660 * - if no other PIC bits are set in params->hdr->e_flags
661 * - we assume that the LOADable segments in the binary are independently relocatable
662 * - we assume R/O executable segments are shareable
663 * - else
664 * - we assume the loadable parts of the image to require fixed displacement
665 * - the image is not shareable
666 */
667 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
668 struct file *file,
669 struct mm_struct *mm,
670 const char *what)
671 {
672 struct elf32_fdpic_loadmap *loadmap;
673 #ifdef CONFIG_MMU
674 struct elf32_fdpic_loadseg *mseg;
675 #endif
676 struct elf32_fdpic_loadseg *seg;
677 struct elf32_phdr *phdr;
678 unsigned long load_addr, stop;
679 unsigned nloads, tmp;
680 size_t size;
681 int loop, ret;
682
683 /* allocate a load map table */
684 nloads = 0;
685 for (loop = 0; loop < params->hdr.e_phnum; loop++)
686 if (params->phdrs[loop].p_type == PT_LOAD)
687 nloads++;
688
689 if (nloads == 0)
690 return -ELIBBAD;
691
692 size = sizeof(*loadmap) + nloads * sizeof(*seg);
693 loadmap = kmalloc(size, GFP_KERNEL);
694 if (!loadmap)
695 return -ENOMEM;
696
697 params->loadmap = loadmap;
698 memset(loadmap, 0, size);
699
700 loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
701 loadmap->nsegs = nloads;
702
703 load_addr = params->load_addr;
704 seg = loadmap->segs;
705
706 /* map the requested LOADs into the memory space */
707 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
708 case ELF_FDPIC_FLAG_CONSTDISP:
709 case ELF_FDPIC_FLAG_CONTIGUOUS:
710 #ifndef CONFIG_MMU
711 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
712 if (ret < 0)
713 return ret;
714 break;
715 #endif
716 default:
717 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
718 if (ret < 0)
719 return ret;
720 break;
721 }
722
723 /* map the entry point */
724 if (params->hdr.e_entry) {
725 seg = loadmap->segs;
726 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
727 if (params->hdr.e_entry >= seg->p_vaddr &&
728 params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
729 ) {
730 params->entry_addr =
731 (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
732 break;
733 }
734 }
735 }
736
737 /* determine where the program header table has wound up if mapped */
738 stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
739 phdr = params->phdrs;
740
741 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
742 if (phdr->p_type != PT_LOAD)
743 continue;
744
745 if (phdr->p_offset > params->hdr.e_phoff ||
746 phdr->p_offset + phdr->p_filesz < stop)
747 continue;
748
749 seg = loadmap->segs;
750 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
751 if (phdr->p_vaddr >= seg->p_vaddr &&
752 phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
753 ) {
754 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
755 params->hdr.e_phoff - phdr->p_offset;
756 break;
757 }
758 }
759 break;
760 }
761
762 /* determine where the dynamic section has wound up if there is one */
763 phdr = params->phdrs;
764 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
765 if (phdr->p_type != PT_DYNAMIC)
766 continue;
767
768 seg = loadmap->segs;
769 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
770 if (phdr->p_vaddr >= seg->p_vaddr &&
771 phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
772 ) {
773 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
774
775 /* check the dynamic section contains at least one item, and that
776 * the last item is a NULL entry */
777 if (phdr->p_memsz == 0 ||
778 phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
779 goto dynamic_error;
780
781 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
782 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
783 goto dynamic_error;
784 break;
785 }
786 }
787 break;
788 }
789
790 /* now elide adjacent segments in the load map on MMU linux
791 * - on uClinux the holes between may actually be filled with system stuff or stuff from
792 * other processes
793 */
794 #ifdef CONFIG_MMU
795 nloads = loadmap->nsegs;
796 mseg = loadmap->segs;
797 seg = mseg + 1;
798 for (loop = 1; loop < nloads; loop++) {
799 /* see if we have a candidate for merging */
800 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
801 load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
802 if (load_addr == (seg->addr & PAGE_MASK)) {
803 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
804 mseg->p_memsz += seg->addr & ~PAGE_MASK;
805 mseg->p_memsz += seg->p_memsz;
806 loadmap->nsegs--;
807 continue;
808 }
809 }
810
811 mseg++;
812 if (mseg != seg)
813 *mseg = *seg;
814 }
815 #endif
816
817 kdebug("Mapped Object [%s]:", what);
818 kdebug("- elfhdr : %lx", params->elfhdr_addr);
819 kdebug("- entry : %lx", params->entry_addr);
820 kdebug("- PHDR[] : %lx", params->ph_addr);
821 kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
822 seg = loadmap->segs;
823 for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
824 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
825 loop,
826 seg->addr, seg->addr + seg->p_memsz - 1,
827 seg->p_vaddr, seg->p_memsz);
828
829 return 0;
830
831 dynamic_error:
832 printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
833 what, file->f_dentry->d_inode->i_ino);
834 return -ELIBBAD;
835 } /* end elf_fdpic_map_file() */
836
837 /*****************************************************************************/
838 /*
839 * map a file with constant displacement under uClinux
840 */
841 #ifndef CONFIG_MMU
842 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
843 struct file *file,
844 struct mm_struct *mm)
845 {
846 struct elf32_fdpic_loadseg *seg;
847 struct elf32_phdr *phdr;
848 unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
849 loff_t fpos;
850 int loop, ret;
851
852 load_addr = params->load_addr;
853 seg = params->loadmap->segs;
854
855 /* determine the bounds of the contiguous overall allocation we must make */
856 phdr = params->phdrs;
857 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
858 if (params->phdrs[loop].p_type != PT_LOAD)
859 continue;
860
861 if (base > phdr->p_vaddr)
862 base = phdr->p_vaddr;
863 if (top < phdr->p_vaddr + phdr->p_memsz)
864 top = phdr->p_vaddr + phdr->p_memsz;
865 }
866
867 /* allocate one big anon block for everything */
868 mflags = MAP_PRIVATE;
869 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
870 mflags |= MAP_EXECUTABLE;
871
872 down_write(&mm->mmap_sem);
873 maddr = do_mmap(NULL, load_addr, top - base,
874 PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
875 up_write(&mm->mmap_sem);
876 if (IS_ERR((void *) maddr))
877 return (int) maddr;
878
879 if (load_addr != 0)
880 load_addr += PAGE_ALIGN(top - base);
881
882 /* and then load the file segments into it */
883 phdr = params->phdrs;
884 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
885 if (params->phdrs[loop].p_type != PT_LOAD)
886 continue;
887
888 fpos = phdr->p_offset;
889
890 seg->addr = maddr + (phdr->p_vaddr - base);
891 seg->p_vaddr = phdr->p_vaddr;
892 seg->p_memsz = phdr->p_memsz;
893
894 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
895 if (ret < 0)
896 return ret;
897
898 /* map the ELF header address if in this segment */
899 if (phdr->p_offset == 0)
900 params->elfhdr_addr = seg->addr;
901
902 /* clear any space allocated but not loaded */
903 if (phdr->p_filesz < phdr->p_memsz)
904 clear_user((void *) (seg->addr + phdr->p_filesz),
905 phdr->p_memsz - phdr->p_filesz);
906
907 if (mm) {
908 if (phdr->p_flags & PF_X) {
909 mm->start_code = seg->addr;
910 mm->end_code = seg->addr + phdr->p_memsz;
911 }
912 else if (!mm->start_data) {
913 mm->start_data = seg->addr;
914 #ifndef CONFIG_MMU
915 mm->end_data = seg->addr + phdr->p_memsz;
916 #endif
917 }
918
919 #ifdef CONFIG_MMU
920 if (seg->addr + phdr->p_memsz > mm->end_data)
921 mm->end_data = seg->addr + phdr->p_memsz;
922 #endif
923 }
924
925 seg++;
926 }
927
928 return 0;
929 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */
930 #endif
931
932 /*****************************************************************************/
933 /*
934 * map a binary by direct mmap() of the individual PT_LOAD segments
935 */
936 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
937 struct file *file,
938 struct mm_struct *mm)
939 {
940 struct elf32_fdpic_loadseg *seg;
941 struct elf32_phdr *phdr;
942 unsigned long load_addr, delta_vaddr;
943 int loop, dvset;
944
945 load_addr = params->load_addr;
946 delta_vaddr = 0;
947 dvset = 0;
948
949 seg = params->loadmap->segs;
950
951 /* deal with each load segment separately */
952 phdr = params->phdrs;
953 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
954 unsigned long maddr, disp, excess, excess1;
955 int prot = 0, flags;
956
957 if (phdr->p_type != PT_LOAD)
958 continue;
959
960 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
961 (unsigned long) phdr->p_vaddr,
962 (unsigned long) phdr->p_offset,
963 (unsigned long) phdr->p_filesz,
964 (unsigned long) phdr->p_memsz);
965
966 /* determine the mapping parameters */
967 if (phdr->p_flags & PF_R) prot |= PROT_READ;
968 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
969 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
970
971 flags = MAP_PRIVATE | MAP_DENYWRITE;
972 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
973 flags |= MAP_EXECUTABLE;
974
975 maddr = 0;
976
977 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
978 case ELF_FDPIC_FLAG_INDEPENDENT:
979 /* PT_LOADs are independently locatable */
980 break;
981
982 case ELF_FDPIC_FLAG_HONOURVADDR:
983 /* the specified virtual address must be honoured */
984 maddr = phdr->p_vaddr;
985 flags |= MAP_FIXED;
986 break;
987
988 case ELF_FDPIC_FLAG_CONSTDISP:
989 /* constant displacement
990 * - can be mapped anywhere, but must be mapped as a unit
991 */
992 if (!dvset) {
993 maddr = load_addr;
994 delta_vaddr = phdr->p_vaddr;
995 dvset = 1;
996 }
997 else {
998 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
999 flags |= MAP_FIXED;
1000 }
1001 break;
1002
1003 case ELF_FDPIC_FLAG_CONTIGUOUS:
1004 /* contiguity handled later */
1005 break;
1006
1007 default:
1008 BUG();
1009 }
1010
1011 maddr &= PAGE_MASK;
1012
1013 /* create the mapping */
1014 disp = phdr->p_vaddr & ~PAGE_MASK;
1015 down_write(&mm->mmap_sem);
1016 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1017 phdr->p_offset - disp);
1018 up_write(&mm->mmap_sem);
1019
1020 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1021 loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1022 maddr);
1023
1024 if (IS_ERR((void *) maddr))
1025 return (int) maddr;
1026
1027 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1028 load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1029
1030 seg->addr = maddr + disp;
1031 seg->p_vaddr = phdr->p_vaddr;
1032 seg->p_memsz = phdr->p_memsz;
1033
1034 /* map the ELF header address if in this segment */
1035 if (phdr->p_offset == 0)
1036 params->elfhdr_addr = seg->addr;
1037
1038 /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1039 if (prot & PROT_WRITE && disp > 0) {
1040 kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1041 clear_user((void *) maddr, disp);
1042 maddr += disp;
1043 }
1044
1045 /* clear any space allocated but not loaded
1046 * - on uClinux we can just clear the lot
1047 * - on MMU linux we'll get a SIGBUS beyond the last page
1048 * extant in the file
1049 */
1050 excess = phdr->p_memsz - phdr->p_filesz;
1051 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1052
1053 #ifdef CONFIG_MMU
1054
1055 if (excess > excess1) {
1056 unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1057 unsigned long xmaddr;
1058
1059 flags |= MAP_FIXED | MAP_ANONYMOUS;
1060 down_write(&mm->mmap_sem);
1061 xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1062 up_write(&mm->mmap_sem);
1063
1064 kdebug("mmap[%d] <anon>"
1065 " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1066 loop, xaddr, excess - excess1, prot, flags, xmaddr);
1067
1068 if (xmaddr != xaddr)
1069 return -ENOMEM;
1070 }
1071
1072 if (prot & PROT_WRITE && excess1 > 0) {
1073 kdebug("clear[%d] ad=%lx sz=%lx",
1074 loop, maddr + phdr->p_filesz, excess1);
1075 clear_user((void *) maddr + phdr->p_filesz, excess1);
1076 }
1077
1078 #else
1079 if (excess > 0) {
1080 kdebug("clear[%d] ad=%lx sz=%lx",
1081 loop, maddr + phdr->p_filesz, excess);
1082 clear_user((void *) maddr + phdr->p_filesz, excess);
1083 }
1084 #endif
1085
1086 if (mm) {
1087 if (phdr->p_flags & PF_X) {
1088 mm->start_code = maddr;
1089 mm->end_code = maddr + phdr->p_memsz;
1090 }
1091 else if (!mm->start_data) {
1092 mm->start_data = maddr;
1093 mm->end_data = maddr + phdr->p_memsz;
1094 }
1095 }
1096
1097 seg++;
1098 }
1099
1100 return 0;
1101 } /* end elf_fdpic_map_file_by_direct_mmap() */
WRT350N Kernel Patches