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 #include <linux/vs_cvirt.h>
  36
  37 #include <asm/uaccess.h>
  38 #include <asm/param.h>
  39 #include <asm/pgalloc.h>
  40
  41 typedef char *elf_caddr_t;
  42 #ifndef elf_addr_t
  43 #define elf_addr_t unsigned long
  44 #endif
  45
  46 #if 0
  47 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  48 #else
  49 #define kdebug(fmt, ...) do {} while(0)
  50 #endif
  51
  52 MODULE_LICENSE("GPL");
  53
  54 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  55 //static int load_elf_fdpic_library(struct file *);
  56 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file);
  57 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
  58                               struct file *file,
  59                               struct mm_struct *mm,
  60                               const char *what);
  61
  62 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
  63                                    struct mm_struct *mm,
  64                                    struct elf_fdpic_params *exec_params,
  65                                    struct elf_fdpic_params *interp_params);
  66
  67 #ifndef CONFIG_MMU
  68 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp);
  69 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
  70                                                    struct file *file,
  71                                                    struct mm_struct *mm);
  72 #endif
  73
  74 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
  75                                              struct file *file,
  76                                              struct mm_struct *mm);
  77
  78 static struct linux_binfmt elf_fdpic_format = {
  79         .module         = THIS_MODULE,
  80         .load_binary    = load_elf_fdpic_binary,
  81 //      .load_shlib     = load_elf_fdpic_library,
  82 //      .core_dump      = elf_fdpic_core_dump,
  83         .min_coredump   = ELF_EXEC_PAGESIZE,
  84 };
  85
  86 static int __init init_elf_fdpic_binfmt(void)  { return register_binfmt(&elf_fdpic_format); }
  87 static void __exit exit_elf_fdpic_binfmt(void) { unregister_binfmt(&elf_fdpic_format); }
  88
  89 module_init(init_elf_fdpic_binfmt)
  90 module_exit(exit_elf_fdpic_binfmt)
  91
  92 static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
  93 {
  94         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
  95                 return 0;
  96         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
  97                 return 0;
  98         if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
  99                 return 0;
 100         if (!file->f_op || !file->f_op->mmap)
 101                 return 0;
 102         return 1;
 103 }
 104
 105 /*****************************************************************************/
 106 /*
 107  * read the program headers table into memory
 108  */
 109 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file)
 110 {
 111         struct elf32_phdr *phdr;
 112         unsigned long size;
 113         int retval, loop;
 114
 115         if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 116                 return -ENOMEM;
 117         if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
 118                 return -ENOMEM;
 119
 120         size = params->hdr.e_phnum * sizeof(struct elf_phdr);
 121         params->phdrs = kmalloc(size, GFP_KERNEL);
 122         if (!params->phdrs)
 123                 return -ENOMEM;
 124
 125         retval = kernel_read(file, params->hdr.e_phoff, (char *) params->phdrs, size);
 126         if (retval < 0)
 127                 return retval;
 128
 129         /* determine stack size for this binary */
 130         phdr = params->phdrs;
 131         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 132                 if (phdr->p_type != PT_GNU_STACK)
 133                         continue;
 134
 135                 if (phdr->p_flags & PF_X)
 136                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
 137                 else
 138                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
 139
 140                 params->stack_size = phdr->p_memsz;
 141                 break;
 142         }
 143
 144         return 0;
 145 } /* end elf_fdpic_fetch_phdrs() */
 146
 147 /*****************************************************************************/
 148 /*
 149  * load an fdpic binary into various bits of memory
 150  */
 151 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 152 {
 153         struct elf_fdpic_params exec_params, interp_params;
 154         struct elf_phdr *phdr;
 155         unsigned long stack_size;
 156         struct file *interpreter = NULL; /* to shut gcc up */
 157         char *interpreter_name = NULL;
 158         int executable_stack;
 159         int retval, i;
 160
 161         memset(&exec_params, 0, sizeof(exec_params));
 162         memset(&interp_params, 0, sizeof(interp_params));
 163
 164         exec_params.hdr = *(struct elfhdr *) bprm->buf;
 165         exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
 166
 167         /* check that this is a binary we know how to deal with */
 168         retval = -ENOEXEC;
 169         if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
 170                 goto error;
 171
 172         /* read the program header table */
 173         retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
 174         if (retval < 0)
 175                 goto error;
 176
 177         /* scan for a program header that specifies an interpreter */
 178         phdr = exec_params.phdrs;
 179
 180         for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
 181                 switch (phdr->p_type) {
 182                 case PT_INTERP:
 183                         retval = -ENOMEM;
 184                         if (phdr->p_filesz > PATH_MAX)
 185                                 goto error;
 186                         retval = -ENOENT;
 187                         if (phdr->p_filesz < 2)
 188                                 goto error;
 189
 190                         /* read the name of the interpreter into memory */
 191                         interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
 192                         if (!interpreter_name)
 193                                 goto error;
 194
 195                         retval = kernel_read(bprm->file,
 196                                              phdr->p_offset,
 197                                              interpreter_name,
 198                                              phdr->p_filesz);
 199                         if (retval < 0)
 200                                 goto error;
 201
 202                         retval = -ENOENT;
 203                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
 204                                 goto error;
 205
 206                         kdebug("Using ELF interpreter %s", interpreter_name);
 207
 208                         /* replace the program with the interpreter */
 209                         interpreter = open_exec(interpreter_name);
 210                         retval = PTR_ERR(interpreter);
 211                         if (IS_ERR(interpreter)) {
 212                                 interpreter = NULL;
 213                                 goto error;
 214                         }
 215
 216                         retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE);
 217                         if (retval < 0)
 218                                 goto error;
 219
 220                         interp_params.hdr = *((struct elfhdr *) bprm->buf);
 221                         break;
 222
 223                 case PT_LOAD:
 224 #ifdef CONFIG_MMU
 225                         if (exec_params.load_addr == 0)
 226                                 exec_params.load_addr = phdr->p_vaddr;
 227 #endif
 228                         break;
 229                 }
 230
 231         }
 232
 233         if (elf_check_const_displacement(&exec_params.hdr))
 234                 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 235
 236         /* perform insanity checks on the interpreter */
 237         if (interpreter_name) {
 238                 retval = -ELIBBAD;
 239                 if (!is_elf_fdpic(&interp_params.hdr, interpreter))
 240                         goto error;
 241
 242                 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
 243
 244                 /* read the interpreter's program header table */
 245                 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
 246                 if (retval < 0)
 247                         goto error;
 248         }
 249
 250         stack_size = exec_params.stack_size;
 251         if (stack_size < interp_params.stack_size)
 252                 stack_size = interp_params.stack_size;
 253
 254         if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 255                 executable_stack = EXSTACK_ENABLE_X;
 256         else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 257                 executable_stack = EXSTACK_DISABLE_X;
 258         else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 259                 executable_stack = EXSTACK_ENABLE_X;
 260         else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 261                 executable_stack = EXSTACK_DISABLE_X;
 262         else
 263                 executable_stack = EXSTACK_DEFAULT;
 264
 265         retval = -ENOEXEC;
 266         if (stack_size == 0)
 267                 goto error;
 268
 269         if (elf_check_const_displacement(&interp_params.hdr))
 270                 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 271
 272         /* flush all traces of the currently running executable */
 273         retval = flush_old_exec(bprm);
 274         if (retval)
 275                 goto error;
 276
 277         /* there's now no turning back... the old userspace image is dead,
 278          * defunct, deceased, etc. after this point we have to exit via
 279          * error_kill */
 280         set_personality(PER_LINUX_FDPIC);
 281         set_binfmt(&elf_fdpic_format);
 282
 283         current->mm->start_code = 0;
 284         current->mm->end_code = 0;
 285         current->mm->start_stack = 0;
 286         current->mm->start_data = 0;
 287         current->mm->end_data = 0;
 288         current->mm->context.exec_fdpic_loadmap = 0;
 289         current->mm->context.interp_fdpic_loadmap = 0;
 290
 291         current->flags &= ~PF_FORKNOEXEC;
 292
 293 #ifdef CONFIG_MMU
 294         elf_fdpic_arch_lay_out_mm(&exec_params,
 295                                   &interp_params,
 296                                   &current->mm->start_stack,
 297                                   &current->mm->start_brk);
 298
 299         retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack);
 300         if (retval < 0) {
 301                 send_sig(SIGKILL, current, 0);
 302                 goto error_kill;
 303         }
 304 #endif
 305
 306         /* load the executable and interpreter into memory */
 307         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable");
 308         if (retval < 0)
 309                 goto error_kill;
 310
 311         if (interpreter_name) {
 312                 retval = elf_fdpic_map_file(&interp_params, interpreter,
 313                                             current->mm, "interpreter");
 314                 if (retval < 0) {
 315                         printk(KERN_ERR "Unable to load interpreter\n");
 316                         goto error_kill;
 317                 }
 318
 319                 allow_write_access(interpreter);
 320                 fput(interpreter);
 321                 interpreter = NULL;
 322         }
 323
 324 #ifdef CONFIG_MMU
 325         if (!current->mm->start_brk)
 326                 current->mm->start_brk = current->mm->end_data;
 327
 328         current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk);
 329
 330 #else
 331         /* create a stack and brk area big enough for everyone
 332          * - the brk heap starts at the bottom and works up
 333          * - the stack starts at the top and works down
 334          */
 335         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 336         if (stack_size < PAGE_SIZE * 2)
 337                 stack_size = PAGE_SIZE * 2;
 338
 339         down_write(&current->mm->mmap_sem);
 340         current->mm->start_brk = do_mmap(NULL,
 341                                          0,
 342                                          stack_size,
 343                                          PROT_READ | PROT_WRITE | PROT_EXEC,
 344                                          MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
 345                                          0);
 346
 347         if (IS_ERR((void *) current->mm->start_brk)) {
 348                 up_write(&current->mm->mmap_sem);
 349                 retval = current->mm->start_brk;
 350                 current->mm->start_brk = 0;
 351                 goto error_kill;
 352         }
 353
 354         if (do_mremap(current->mm->start_brk,
 355                       stack_size,
 356                       ksize((char *) current->mm->start_brk),
 357                       0, 0
 358                       ) == current->mm->start_brk
 359             )
 360                 stack_size = ksize((char *) current->mm->start_brk);
 361         up_write(&current->mm->mmap_sem);
 362
 363         current->mm->brk = current->mm->start_brk;
 364         current->mm->context.end_brk = current->mm->start_brk;
 365         current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
 366         current->mm->start_stack = current->mm->start_brk + stack_size;
 367 #endif
 368
 369         compute_creds(bprm);
 370         current->flags &= ~PF_FORKNOEXEC;
 371         if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0)
 372                 goto error_kill;
 373
 374         kdebug("- start_code  %lx",     (long) current->mm->start_code);
 375         kdebug("- end_code    %lx",     (long) current->mm->end_code);
 376         kdebug("- start_data  %lx",     (long) current->mm->start_data);
 377         kdebug("- end_data    %lx",     (long) current->mm->end_data);
 378         kdebug("- start_brk   %lx",     (long) current->mm->start_brk);
 379         kdebug("- brk         %lx",     (long) current->mm->brk);
 380         kdebug("- start_stack %lx",     (long) current->mm->start_stack);
 381
 382 #ifdef ELF_FDPIC_PLAT_INIT
 383         /*
 384          * The ABI may specify that certain registers be set up in special
 385          * ways (on i386 %edx is the address of a DT_FINI function, for
 386          * example.  This macro performs whatever initialization to
 387          * the regs structure is required.
 388          */
 389         ELF_FDPIC_PLAT_INIT(regs,
 390                             exec_params.map_addr,
 391                             interp_params.map_addr,
 392                             interp_params.dynamic_addr ?: exec_params.dynamic_addr
 393                             );
 394 #endif
 395
 396         /* everything is now ready... get the userspace context ready to roll */
 397         start_thread(regs,
 398                      interp_params.entry_addr ?: exec_params.entry_addr,
 399                      current->mm->start_stack);
 400
 401         if (unlikely(current->ptrace & PT_PTRACED)) {
 402                 if (current->ptrace & PT_TRACE_EXEC)
 403                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 404                 else
 405                         send_sig(SIGTRAP, current, 0);
 406         }
 407
 408         retval = 0;
 409
 410 error:
 411         if (interpreter) {
 412                 allow_write_access(interpreter);
 413                 fput(interpreter);
 414         }
 415         kfree(interpreter_name);
 416         kfree(exec_params.phdrs);
 417         kfree(exec_params.loadmap);
 418         kfree(interp_params.phdrs);
 419         kfree(interp_params.loadmap);
 420         return retval;
 421
 422         /* unrecoverable error - kill the process */
 423  error_kill:
 424         send_sig(SIGSEGV, current, 0);
 425         goto error;
 426
 427 } /* end load_elf_fdpic_binary() */
 428
 429 /*****************************************************************************/
 430 /*
 431  * present useful information to the program
 432  */
 433 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 434                                    struct mm_struct *mm,
 435                                    struct elf_fdpic_params *exec_params,
 436                                    struct elf_fdpic_params *interp_params)
 437 {
 438         unsigned long sp, csp, nitems;
 439         elf_caddr_t *argv, *envp;
 440         size_t platform_len = 0, len;
 441         char *k_platform, *u_platform, *p;
 442         long hwcap;
 443         int loop;
 444
 445         /* we're going to shovel a whole load of stuff onto the stack */
 446 #ifdef CONFIG_MMU
 447         sp = bprm->p;
 448 #else
 449         sp = mm->start_stack;
 450
 451         /* stack the program arguments and environment */
 452         if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
 453                 return -EFAULT;
 454 #endif
 455
 456         /* get hold of platform and hardware capabilities masks for the machine
 457          * we are running on.  In some cases (Sparc), this info is impossible
 458          * to get, in others (i386) it is merely difficult.
 459          */
 460         hwcap = ELF_HWCAP;
 461         k_platform = ELF_PLATFORM;
 462
 463         if (k_platform) {
 464                 platform_len = strlen(k_platform) + 1;
 465                 sp -= platform_len;
 466                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 467                         return -EFAULT;
 468         }
 469
 470         u_platform = (char *) sp;
 471
 472 #if defined(__i386__) && defined(CONFIG_SMP)
 473         /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 474          * by the processes running on the same package. One thing we can do
 475          * is to shuffle the initial stack for them.
 476          *
 477          * the conditionals here are unneeded, but kept in to make the
 478          * code behaviour the same as pre change unless we have hyperthreaded
 479          * processors. This keeps Mr Marcelo Person happier but should be
 480          * removed for 2.5
 481          */
 482         if (smp_num_siblings > 1)
 483                 sp = sp - ((current->pid % 64) << 7);
 484 #endif
 485
 486         sp &= ~7UL;
 487
 488         /* stack the load map(s) */
 489         len = sizeof(struct elf32_fdpic_loadmap);
 490         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 491         sp = (sp - len) & ~7UL;
 492         exec_params->map_addr = sp;
 493
 494         if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
 495                 return -EFAULT;
 496
 497         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 498
 499         if (interp_params->loadmap) {
 500                 len = sizeof(struct elf32_fdpic_loadmap);
 501                 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
 502                 sp = (sp - len) & ~7UL;
 503                 interp_params->map_addr = sp;
 504
 505                 if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0)
 506                         return -EFAULT;
 507
 508                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 509         }
 510
 511         /* force 16 byte _final_ alignment here for generality */
 512 #define DLINFO_ITEMS 13
 513
 514         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
 515 #ifdef DLINFO_ARCH_ITEMS
 516         nitems += DLINFO_ARCH_ITEMS;
 517 #endif
 518
 519         csp = sp;
 520         sp -= nitems * 2 * sizeof(unsigned long);
 521         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 522         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 523         sp -= 1 * sizeof(unsigned long);                /* argc */
 524
 525         csp -= sp & 15UL;
 526         sp -= sp & 15UL;
 527
 528         /* put the ELF interpreter info on the stack */
 529 #define NEW_AUX_ENT(nr, id, val)                                                \
 530         do {                                                                    \
 531                 struct { unsigned long _id, _val; } *ent = (void *) csp;        \
 532                 __put_user((id), &ent[nr]._id);                                 \
 533                 __put_user((val), &ent[nr]._val);                               \
 534         } while (0)
 535
 536         csp -= 2 * sizeof(unsigned long);
 537         NEW_AUX_ENT(0, AT_NULL, 0);
 538         if (k_platform) {
 539                 csp -= 2 * sizeof(unsigned long);
 540                 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
 541         }
 542
 543         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 544         NEW_AUX_ENT( 0, AT_HWCAP,               hwcap);
 545         NEW_AUX_ENT( 1, AT_PAGESZ,              PAGE_SIZE);
 546         NEW_AUX_ENT( 2, AT_CLKTCK,              CLOCKS_PER_SEC);
 547         NEW_AUX_ENT( 3, AT_PHDR,                exec_params->ph_addr);
 548         NEW_AUX_ENT( 4, AT_PHENT,               sizeof(struct elf_phdr));
 549         NEW_AUX_ENT( 5, AT_PHNUM,               exec_params->hdr.e_phnum);
 550         NEW_AUX_ENT( 6, AT_BASE,                interp_params->elfhdr_addr);
 551         NEW_AUX_ENT( 7, AT_FLAGS,               0);
 552         NEW_AUX_ENT( 8, AT_ENTRY,               exec_params->entry_addr);
 553         NEW_AUX_ENT( 9, AT_UID,                 (elf_addr_t) current->uid);
 554         NEW_AUX_ENT(10, AT_EUID,                (elf_addr_t) current->euid);
 555         NEW_AUX_ENT(11, AT_GID,                 (elf_addr_t) current->gid);
 556         NEW_AUX_ENT(12, AT_EGID,                (elf_addr_t) current->egid);
 557
 558 #ifdef ARCH_DLINFO
 559         /* ARCH_DLINFO must come last so platform specific code can enforce
 560          * special alignment requirements on the AUXV if necessary (eg. PPC).
 561          */
 562         ARCH_DLINFO;
 563 #endif
 564 #undef NEW_AUX_ENT
 565
 566         /* allocate room for argv[] and envv[] */
 567         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 568         envp = (elf_caddr_t *) csp;
 569         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 570         argv = (elf_caddr_t *) csp;
 571
 572         /* stack argc */
 573         csp -= sizeof(unsigned long);
 574         __put_user(bprm->argc, (unsigned long *) csp);
 575
 576         if (csp != sp)
 577                 BUG();
 578
 579         /* fill in the argv[] array */
 580 #ifdef CONFIG_MMU
 581         current->mm->arg_start = bprm->p;
 582 #else
 583         current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 584 #endif
 585
 586         p = (char *) current->mm->arg_start;
 587         for (loop = bprm->argc; loop > 0; loop--) {
 588                 __put_user((elf_caddr_t) p, argv++);
 589                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 590                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 591                         return -EINVAL;
 592                 p += len;
 593         }
 594         __put_user(NULL, argv);
 595         current->mm->arg_end = (unsigned long) p;
 596
 597         /* fill in the envv[] array */
 598         current->mm->env_start = (unsigned long) p;
 599         for (loop = bprm->envc; loop > 0; loop--) {
 600                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
 601                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 602                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 603                         return -EINVAL;
 604                 p += len;
 605         }
 606         __put_user(NULL, envp);
 607         current->mm->env_end = (unsigned long) p;
 608
 609         mm->start_stack = (unsigned long) sp;
 610         return 0;
 611 } /* end create_elf_fdpic_tables() */
 612
 613 /*****************************************************************************/
 614 /*
 615  * transfer the program arguments and environment from the holding pages onto
 616  * the stack
 617  */
 618 #ifndef CONFIG_MMU
 619 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
 620 {
 621         unsigned long index, stop, sp;
 622         char *src;
 623         int ret = 0;
 624
 625         stop = bprm->p >> PAGE_SHIFT;
 626         sp = *_sp;
 627
 628         for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
 629                 src = kmap(bprm->page[index]);
 630                 sp -= PAGE_SIZE;
 631                 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
 632                         ret = -EFAULT;
 633                 kunmap(bprm->page[index]);
 634                 if (ret < 0)
 635                         goto out;
 636         }
 637
 638         *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
 639
 640  out:
 641         return ret;
 642 } /* end elf_fdpic_transfer_args_to_stack() */
 643 #endif
 644
 645 /*****************************************************************************/
 646 /*
 647  * load the appropriate binary image (executable or interpreter) into memory
 648  * - we assume no MMU is available
 649  * - if no other PIC bits are set in params->hdr->e_flags
 650  *   - we assume that the LOADable segments in the binary are independently relocatable
 651  *   - we assume R/O executable segments are shareable
 652  * - else
 653  *   - we assume the loadable parts of the image to require fixed displacement
 654  *   - the image is not shareable
 655  */
 656 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 657                               struct file *file,
 658                               struct mm_struct *mm,
 659                               const char *what)
 660 {
 661         struct elf32_fdpic_loadmap *loadmap;
 662 #ifdef CONFIG_MMU
 663         struct elf32_fdpic_loadseg *mseg;
 664 #endif
 665         struct elf32_fdpic_loadseg *seg;
 666         struct elf32_phdr *phdr;
 667         unsigned long load_addr, stop;
 668         unsigned nloads, tmp;
 669         size_t size;
 670         int loop, ret;
 671
 672         /* allocate a load map table */
 673         nloads = 0;
 674         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 675                 if (params->phdrs[loop].p_type == PT_LOAD)
 676                         nloads++;
 677
 678         if (nloads == 0)
 679                 return -ELIBBAD;
 680
 681         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 682         loadmap = kmalloc(size, GFP_KERNEL);
 683         if (!loadmap)
 684                 return -ENOMEM;
 685
 686         params->loadmap = loadmap;
 687         memset(loadmap, 0, size);
 688
 689         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 690         loadmap->nsegs = nloads;
 691
 692         load_addr = params->load_addr;
 693         seg = loadmap->segs;
 694
 695         /* map the requested LOADs into the memory space */
 696         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 697         case ELF_FDPIC_FLAG_CONSTDISP:
 698         case ELF_FDPIC_FLAG_CONTIGUOUS:
 699 #ifndef CONFIG_MMU
 700                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 701                 if (ret < 0)
 702                         return ret;
 703                 break;
 704 #endif
 705         default:
 706                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 707                 if (ret < 0)
 708                         return ret;
 709                 break;
 710         }
 711
 712         /* map the entry point */
 713         if (params->hdr.e_entry) {
 714                 seg = loadmap->segs;
 715                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 716                         if (params->hdr.e_entry >= seg->p_vaddr &&
 717                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
 718                             ) {
 719                                 params->entry_addr =
 720                                         (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
 721                                 break;
 722                         }
 723                 }
 724         }
 725
 726         /* determine where the program header table has wound up if mapped */
 727         stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
 728         phdr = params->phdrs;
 729
 730         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 731                 if (phdr->p_type != PT_LOAD)
 732                         continue;
 733
 734                 if (phdr->p_offset > params->hdr.e_phoff ||
 735                     phdr->p_offset + phdr->p_filesz < stop)
 736                         continue;
 737
 738                 seg = loadmap->segs;
 739                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 740                         if (phdr->p_vaddr >= seg->p_vaddr &&
 741                             phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
 742                             ) {
 743                                 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
 744                                         params->hdr.e_phoff - phdr->p_offset;
 745                                 break;
 746                         }
 747                 }
 748                 break;
 749         }
 750
 751         /* determine where the dynamic section has wound up if there is one */
 752         phdr = params->phdrs;
 753         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 754                 if (phdr->p_type != PT_DYNAMIC)
 755                         continue;
 756
 757                 seg = loadmap->segs;
 758                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 759                         if (phdr->p_vaddr >= seg->p_vaddr &&
 760                             phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
 761                             ) {
 762                                 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
 763
 764                                 /* check the dynamic section contains at least one item, and that
 765                                  * the last item is a NULL entry */
 766                                 if (phdr->p_memsz == 0 ||
 767                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 768                                         goto dynamic_error;
 769
 770                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 771                                 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
 772                                         goto dynamic_error;
 773                                 break;
 774                         }
 775                 }
 776                 break;
 777         }
 778
 779         /* now elide adjacent segments in the load map on MMU linux
 780          * - on uClinux the holes between may actually be filled with system stuff or stuff from
 781          *   other processes
 782          */
 783 #ifdef CONFIG_MMU
 784         nloads = loadmap->nsegs;
 785         mseg = loadmap->segs;
 786         seg = mseg + 1;
 787         for (loop = 1; loop < nloads; loop++) {
 788                 /* see if we have a candidate for merging */
 789                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 790                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 791                         if (load_addr == (seg->addr & PAGE_MASK)) {
 792                                 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
 793                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 794                                 mseg->p_memsz += seg->p_memsz;
 795                                 loadmap->nsegs--;
 796                                 continue;
 797                         }
 798                 }
 799
 800                 mseg++;
 801                 if (mseg != seg)
 802                         *mseg = *seg;
 803         }
 804 #endif
 805
 806         kdebug("Mapped Object [%s]:", what);
 807         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 808         kdebug("- entry    : %lx", params->entry_addr);
 809         kdebug("- PHDR[]   : %lx", params->ph_addr);
 810         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 811         seg = loadmap->segs;
 812         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 813                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 814                        loop,
 815                        seg->addr, seg->addr + seg->p_memsz - 1,
 816                        seg->p_vaddr, seg->p_memsz);
 817
 818         return 0;
 819
 820  dynamic_error:
 821         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 822                what, file->f_dentry->d_inode->i_ino);
 823         return -ELIBBAD;
 824 } /* end elf_fdpic_map_file() */
 825
 826 /*****************************************************************************/
 827 /*
 828  * map a file with constant displacement under uClinux
 829  */
 830 #ifndef CONFIG_MMU
 831 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
 832                                                    struct file *file,
 833                                                    struct mm_struct *mm)
 834 {
 835         struct elf32_fdpic_loadseg *seg;
 836         struct elf32_phdr *phdr;
 837         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 838         loff_t fpos;
 839         int loop, ret;
 840
 841         load_addr = params->load_addr;
 842         seg = params->loadmap->segs;
 843
 844         /* determine the bounds of the contiguous overall allocation we must make */
 845         phdr = params->phdrs;
 846         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 847                 if (params->phdrs[loop].p_type != PT_LOAD)
 848                         continue;
 849
 850                 if (base > phdr->p_vaddr)
 851                         base = phdr->p_vaddr;
 852                 if (top < phdr->p_vaddr + phdr->p_memsz)
 853                         top = phdr->p_vaddr + phdr->p_memsz;
 854         }
 855
 856         /* allocate one big anon block for everything */
 857         mflags = MAP_PRIVATE;
 858         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 859                 mflags |= MAP_EXECUTABLE;
 860
 861         down_write(&mm->mmap_sem);
 862         maddr = do_mmap(NULL, load_addr, top - base,
 863                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 864         up_write(&mm->mmap_sem);
 865         if (IS_ERR((void *) maddr))
 866                 return (int) maddr;
 867
 868         if (load_addr != 0)
 869                 load_addr += PAGE_ALIGN(top - base);
 870
 871         /* and then load the file segments into it */
 872         phdr = params->phdrs;
 873         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 874                 if (params->phdrs[loop].p_type != PT_LOAD)
 875                         continue;
 876
 877                 fpos = phdr->p_offset;
 878
 879                 seg->addr = maddr + (phdr->p_vaddr - base);
 880                 seg->p_vaddr = phdr->p_vaddr;
 881                 seg->p_memsz = phdr->p_memsz;
 882
 883                 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
 884                 if (ret < 0)
 885                         return ret;
 886
 887                 /* map the ELF header address if in this segment */
 888                 if (phdr->p_offset == 0)
 889                         params->elfhdr_addr = seg->addr;
 890
 891                 /* clear any space allocated but not loaded */
 892                 if (phdr->p_filesz < phdr->p_memsz)
 893                         clear_user((void *) (seg->addr + phdr->p_filesz),
 894                                    phdr->p_memsz - phdr->p_filesz);
 895
 896                 if (mm) {
 897                         if (phdr->p_flags & PF_X) {
 898                                 mm->start_code = seg->addr;
 899                                 mm->end_code = seg->addr + phdr->p_memsz;
 900                         }
 901                         else if (!mm->start_data) {
 902                                 mm->start_data = seg->addr;
 903 #ifndef CONFIG_MMU
 904                                 mm->end_data = seg->addr + phdr->p_memsz;
 905 #endif
 906                         }
 907
 908 #ifdef CONFIG_MMU
 909                         if (seg->addr + phdr->p_memsz > mm->end_data)
 910                                 mm->end_data = seg->addr + phdr->p_memsz;
 911 #endif
 912                 }
 913
 914                 seg++;
 915         }
 916
 917         return 0;
 918 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */
 919 #endif
 920
 921 /*****************************************************************************/
 922 /*
 923  * map a binary by direct mmap() of the individual PT_LOAD segments
 924  */
 925 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 926                                              struct file *file,
 927                                              struct mm_struct *mm)
 928 {
 929         struct elf32_fdpic_loadseg *seg;
 930         struct elf32_phdr *phdr;
 931         unsigned long load_addr, delta_vaddr;
 932         int loop, dvset;
 933
 934         load_addr = params->load_addr;
 935         delta_vaddr = 0;
 936         dvset = 0;
 937
 938         seg = params->loadmap->segs;
 939
 940         /* deal with each load segment separately */
 941         phdr = params->phdrs;
 942         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 943                 unsigned long maddr, disp, excess, excess1;
 944                 int prot = 0, flags;
 945
 946                 if (phdr->p_type != PT_LOAD)
 947                         continue;
 948
 949                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
 950                        (unsigned long) phdr->p_vaddr,
 951                        (unsigned long) phdr->p_offset,
 952                        (unsigned long) phdr->p_filesz,
 953                        (unsigned long) phdr->p_memsz);
 954
 955                 /* determine the mapping parameters */
 956                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
 957                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
 958                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
 959
 960                 flags = MAP_PRIVATE | MAP_DENYWRITE;
 961                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 962                         flags |= MAP_EXECUTABLE;
 963
 964                 maddr = 0;
 965
 966                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 967                 case ELF_FDPIC_FLAG_INDEPENDENT:
 968                         /* PT_LOADs are independently locatable */
 969                         break;
 970
 971                 case ELF_FDPIC_FLAG_HONOURVADDR:
 972                         /* the specified virtual address must be honoured */
 973                         maddr = phdr->p_vaddr;
 974                         flags |= MAP_FIXED;
 975                         break;
 976
 977                 case ELF_FDPIC_FLAG_CONSTDISP:
 978                         /* constant displacement
 979                          * - can be mapped anywhere, but must be mapped as a unit
 980                          */
 981                         if (!dvset) {
 982                                 maddr = load_addr;
 983                                 delta_vaddr = phdr->p_vaddr;
 984                                 dvset = 1;
 985                         }
 986                         else {
 987                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
 988                                 flags |= MAP_FIXED;
 989                         }
 990                         break;
 991
 992                 case ELF_FDPIC_FLAG_CONTIGUOUS:
 993                         /* contiguity handled later */
 994                         break;
 995
 996                 default:
 997                         BUG();
 998                 }
 999
1000                 maddr &= PAGE_MASK;
1001
1002                 /* create the mapping */
1003                 disp = phdr->p_vaddr & ~PAGE_MASK;
1004                 down_write(&mm->mmap_sem);
1005                 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1006                                 phdr->p_offset - disp);
1007                 up_write(&mm->mmap_sem);
1008
1009                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1010                        loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1011                        maddr);
1012
1013                 if (IS_ERR((void *) maddr))
1014                         return (int) maddr;
1015
1016                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1017                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1018
1019                 seg->addr = maddr + disp;
1020                 seg->p_vaddr = phdr->p_vaddr;
1021                 seg->p_memsz = phdr->p_memsz;
1022
1023                 /* map the ELF header address if in this segment */
1024                 if (phdr->p_offset == 0)
1025                         params->elfhdr_addr = seg->addr;
1026
1027                 /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1028                 if (prot & PROT_WRITE && disp > 0) {
1029                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1030                         clear_user((void *) maddr, disp);
1031                         maddr += disp;
1032                 }
1033
1034                 /* clear any space allocated but not loaded
1035                  * - on uClinux we can just clear the lot
1036                  * - on MMU linux we'll get a SIGBUS beyond the last page
1037                  *   extant in the file
1038                  */
1039                 excess = phdr->p_memsz - phdr->p_filesz;
1040                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1041
1042 #ifdef CONFIG_MMU
1043
1044                 if (excess > excess1) {
1045                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1046                         unsigned long xmaddr;
1047
1048                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1049                         down_write(&mm->mmap_sem);
1050                         xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1051                         up_write(&mm->mmap_sem);
1052
1053                         kdebug("mmap[%d] <anon>"
1054                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1055                                loop, xaddr, excess - excess1, prot, flags, xmaddr);
1056
1057                         if (xmaddr != xaddr)
1058                                 return -ENOMEM;
1059                 }
1060
1061                 if (prot & PROT_WRITE && excess1 > 0) {
1062                         kdebug("clear[%d] ad=%lx sz=%lx",
1063                                loop, maddr + phdr->p_filesz, excess1);
1064                         clear_user((void *) maddr + phdr->p_filesz, excess1);
1065                 }
1066
1067 #else
1068                 if (excess > 0) {
1069                         kdebug("clear[%d] ad=%lx sz=%lx",
1070                                loop, maddr + phdr->p_filesz, excess);
1071                         clear_user((void *) maddr + phdr->p_filesz, excess);
1072                 }
1073 #endif
1074
1075                 if (mm) {
1076                         if (phdr->p_flags & PF_X) {
1077                                 mm->start_code = maddr;
1078                                 mm->end_code = maddr + phdr->p_memsz;
1079                         }
1080                         else if (!mm->start_data) {
1081                                 mm->start_data = maddr;
1082                                 mm->end_data = maddr + phdr->p_memsz;
1083                         }
1084                 }
1085
1086                 seg++;
1087         }
1088
1089         return 0;
1090 } /* end elf_fdpic_map_file_by_direct_mmap() */