git.oblomov.eu Git - linux-2.6/blob - 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
 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() */