Linux-2.6.12-rc2
[linux-2.6.git] / fs / binfmt_elf_fdpic.c
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() */