fs/binfmt_elf_fdpic.c

   1 /* binfmt_elf_fdpic.c: FDPIC ELF binary format
   2  *
   3  * Copyright (C) 2003, 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  * Derived from binfmt_elf.c
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14
  15 #include <linux/fs.h>
  16 #include <linux/stat.h>
  17 #include <linux/sched.h>
  18 #include <linux/mm.h>
  19 #include <linux/mman.h>
  20 #include <linux/errno.h>
  21 #include <linux/signal.h>
  22 #include <linux/binfmts.h>
  23 #include <linux/string.h>
  24 #include <linux/file.h>
  25 #include <linux/fcntl.h>
  26 #include <linux/slab.h>
  27 #include <linux/highmem.h>
  28 #include <linux/personality.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/init.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/elf.h>
  33 #include <linux/elf-fdpic.h>
  34 #include <linux/elfcore.h>
  35
  36 #include <asm/uaccess.h>
  37 #include <asm/param.h>
  38 #include <asm/pgalloc.h>
  39
  40 typedef char *elf_caddr_t;
  41 #ifndef elf_addr_t
  42 #define elf_addr_t unsigned long
  43 #endif
  44
  45 #if 0
  46 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  47 #else
  48 #define kdebug(fmt, ...) do {} while(0)
  49 #endif
  50
  51 MODULE_LICENSE("GPL");
  52
  53 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  54 //static int load_elf_fdpic_library(struct file *);
  55 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file);
  56 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
  57                               struct file *file,
  58                               struct mm_struct *mm,
  59                               const char *what);
  60
  61 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
  62                                    struct mm_struct *mm,
  63                                    struct elf_fdpic_params *exec_params,
  64                                    struct elf_fdpic_params *interp_params);
  65
  66 #ifndef CONFIG_MMU
  67 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp);
  68 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
  69                                                    struct file *file,
  70                                                    struct mm_struct *mm);
  71 #endif
  72
  73 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
  74                                              struct file *file,
  75                                              struct mm_struct *mm);
  76
  77 static struct linux_binfmt elf_fdpic_format = {
  78         .module         = THIS_MODULE,
  79         .load_binary    = load_elf_fdpic_binary,
  80 //      .load_shlib     = load_elf_fdpic_library,
  81 //      .core_dump      = elf_fdpic_core_dump,
  82         .min_coredump   = ELF_EXEC_PAGESIZE,
  83 };
  84
  85 static int __init init_elf_fdpic_binfmt(void)  { return register_binfmt(&elf_fdpic_format); }
  86 static void __exit exit_elf_fdpic_binfmt(void) { unregister_binfmt(&elf_fdpic_format); }
  87
  88 module_init(init_elf_fdpic_binfmt)
  89 module_exit(exit_elf_fdpic_binfmt)
  90
  91 static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
  92 {
  93         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
  94                 return 0;
  95         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
  96                 return 0;
  97         if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
  98                 return 0;
  99         if (!file->f_op || !file->f_op->mmap)
 100                 return 0;
 101         return 1;
 102 }
 103
 104 /*****************************************************************************/
 105 /*
 106  * read the program headers table into memory
 107  */
 108 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file)
 109 {
 110         struct elf32_phdr *phdr;
 111         unsigned long size;
 112         int retval, loop;
 113
 114         if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 115                 return -ENOMEM;
 116         if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
 117                 return -ENOMEM;
 118
 119         size = params->hdr.e_phnum * sizeof(struct elf_phdr);
 120         params->phdrs = kmalloc(size, GFP_KERNEL);
 121         if (!params->phdrs)
 122                 return -ENOMEM;
 123
 124         retval = kernel_read(file, params->hdr.e_phoff, (char *) params->phdrs, size);
 125         if (retval < 0)
 126                 return retval;
 127
 128         /* determine stack size for this binary */
 129         phdr = params->phdrs;
 130         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 131                 if (phdr->p_type != PT_GNU_STACK)
 132                         continue;
 133
 134                 if (phdr->p_flags & PF_X)
 135                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
 136                 else
 137                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
 138
 139                 params->stack_size = phdr->p_memsz;
 140                 break;
 141         }
 142
 143         return 0;
 144 } /* end elf_fdpic_fetch_phdrs() */
 145
 146 /*****************************************************************************/
 147 /*
 148  * load an fdpic binary into various bits of memory
 149  */
 150 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 151 {
 152         struct elf_fdpic_params exec_params, interp_params;
 153         struct elf_phdr *phdr;
 154         unsigned long stack_size;
 155         struct file *interpreter = NULL; /* to shut gcc up */
 156         char *interpreter_name = NULL;
 157         int executable_stack;
 158         int retval, i;
 159
 160         memset(&exec_params, 0, sizeof(exec_params));
 161         memset(&interp_params, 0, sizeof(interp_params));
 162
 163         exec_params.hdr = *(struct elfhdr *) bprm->buf;
 164         exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
 165
 166         /* check that this is a binary we know how to deal with */
 167         retval = -ENOEXEC;
 168         if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
 169                 goto error;
 170
 171         /* read the program header table */
 172         retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
 173         if (retval < 0)
 174                 goto error;
 175
 176         /* scan for a program header that specifies an interpreter */
 177         phdr = exec_params.phdrs;
 178
 179         for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
 180                 switch (phdr->p_type) {
 181                 case PT_INTERP:
 182                         retval = -ENOMEM;
 183                         if (phdr->p_filesz > PATH_MAX)
 184                                 goto error;
 185                         retval = -ENOENT;
 186                         if (phdr->p_filesz < 2)
 187                                 goto error;
 188
 189                         /* read the name of the interpreter into memory */
 190                         interpreter_name = (char *) kmalloc(phdr->p_filesz, GFP_KERNEL);
 191                         if (!interpreter_name)
 192                                 goto error;
 193
 194                         retval = kernel_read(bprm->file,
 195                                              phdr->p_offset,
 196                                              interpreter_name,
 197                                              phdr->p_filesz);
 198                         if (retval < 0)
 199                                 goto error;
 200
 201                         retval = -ENOENT;
 202                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
 203                                 goto error;
 204
 205                         kdebug("Using ELF interpreter %s", interpreter_name);
 206
 207                         /* replace the program with the interpreter */
 208                         interpreter = open_exec(interpreter_name);
 209                         retval = PTR_ERR(interpreter);
 210                         if (IS_ERR(interpreter)) {
 211                                 interpreter = NULL;
 212                                 goto error;
 213                         }
 214
 215                         retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE);
 216                         if (retval < 0)
 217                                 goto error;
 218
 219                         interp_params.hdr = *((struct elfhdr *) bprm->buf);
 220                         break;
 221
 222                 case PT_LOAD:
 223 #ifdef CONFIG_MMU
 224                         if (exec_params.load_addr == 0)
 225                                 exec_params.load_addr = phdr->p_vaddr;
 226 #endif
 227                         break;
 228                 }
 229
 230         }
 231
 232         if (elf_check_const_displacement(&exec_params.hdr))
 233                 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 234
 235         /* perform insanity checks on the interpreter */
 236         if (interpreter_name) {
 237                 retval = -ELIBBAD;
 238                 if (!is_elf_fdpic(&interp_params.hdr, interpreter))
 239                         goto error;
 240
 241                 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
 242
 243                 /* read the interpreter's program header table */
 244                 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
 245                 if (retval < 0)
 246                         goto error;
 247         }
 248
 249         stack_size = exec_params.stack_size;
 250         if (stack_size < interp_params.stack_size)
 251                 stack_size = interp_params.stack_size;
 252
 253         if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 254                 executable_stack = EXSTACK_ENABLE_X;
 255         else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 256                 executable_stack = EXSTACK_DISABLE_X;
 257         else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 258                 executable_stack = EXSTACK_ENABLE_X;
 259         else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 260                 executable_stack = EXSTACK_DISABLE_X;
 261         else
 262                 executable_stack = EXSTACK_DEFAULT;
 263
 264         retval = -ENOEXEC;
 265         if (stack_size == 0)
 266                 goto error;
 267
 268         if (elf_check_const_displacement(&interp_params.hdr))
 269                 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 270
 271         /* flush all traces of the currently running executable */
 272         retval = flush_old_exec(bprm);
 273         if (retval)
 274                 goto error;
 275
 276         /* there's now no turning back... the old userspace image is dead,
 277          * defunct, deceased, etc. after this point we have to exit via
 278          * error_kill */
 279         set_personality(PER_LINUX_FDPIC);
 280         set_binfmt(&elf_fdpic_format);
 281
 282         current->mm->start_code = 0;
 283         current->mm->end_code = 0;
 284         current->mm->start_stack = 0;
 285         current->mm->start_data = 0;
 286         current->mm->end_data = 0;
 287         current->mm->context.exec_fdpic_loadmap = 0;
 288         current->mm->context.interp_fdpic_loadmap = 0;
 289
 290         current->flags &= ~PF_FORKNOEXEC;
 291
 292 #ifdef CONFIG_MMU
 293         elf_fdpic_arch_lay_out_mm(&exec_params,
 294                                   &interp_params,
 295                                   &current->mm->start_stack,
 296                                   &current->mm->start_brk);
 297 #endif
 298
 299         /* do this so that we can load the interpreter, if need be
 300          * - we will change some of these later
 301          */
 302         set_mm_counter(current->mm, rss, 0);
 303
 304 #ifdef CONFIG_MMU
 305         retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack);
 306         if (retval < 0) {
 307                 send_sig(SIGKILL, current, 0);
 308                 goto error_kill;
 309         }
 310 #endif
 311
 312         /* load the executable and interpreter into memory */
 313         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable");
 314         if (retval < 0)
 315                 goto error_kill;
 316
 317         if (interpreter_name) {
 318                 retval = elf_fdpic_map_file(&interp_params, interpreter,
 319                                             current->mm, "interpreter");
 320                 if (retval < 0) {
 321                         printk(KERN_ERR "Unable to load interpreter\n");
 322                         goto error_kill;
 323                 }
 324
 325                 allow_write_access(interpreter);
 326                 fput(interpreter);
 327                 interpreter = NULL;
 328         }
 329
 330 #ifdef CONFIG_MMU
 331         if (!current->mm->start_brk)
 332                 current->mm->start_brk = current->mm->end_data;
 333
 334         current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk);
 335
 336 #else
 337         /* create a stack and brk area big enough for everyone
 338          * - the brk heap starts at the bottom and works up
 339          * - the stack starts at the top and works down
 340          */
 341         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 342         if (stack_size < PAGE_SIZE * 2)
 343                 stack_size = PAGE_SIZE * 2;
 344
 345         down_write(&current->mm->mmap_sem);
 346         current->mm->start_brk = do_mmap(NULL,
 347                                          0,
 348                                          stack_size,
 349                                          PROT_READ | PROT_WRITE | PROT_EXEC,
 350                                          MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
 351                                          0);
 352
 353         if (IS_ERR((void *) current->mm->start_brk)) {
 354                 up_write(&current->mm->mmap_sem);
 355                 retval = current->mm->start_brk;
 356                 current->mm->start_brk = 0;
 357                 goto error_kill;
 358         }
 359
 360         if (do_mremap(current->mm->start_brk,
 361                       stack_size,
 362                       ksize((char *) current->mm->start_brk),
 363                       0, 0
 364                       ) == current->mm->start_brk
 365             )
 366                 stack_size = ksize((char *) current->mm->start_brk);
 367         up_write(&current->mm->mmap_sem);
 368
 369         current->mm->brk = current->mm->start_brk;
 370         current->mm->context.end_brk = current->mm->start_brk;
 371         current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
 372         current->mm->start_stack = current->mm->start_brk + stack_size;
 373 #endif
 374
 375         compute_creds(bprm);
 376         current->flags &= ~PF_FORKNOEXEC;
 377         if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0)
 378                 goto error_kill;
 379
 380         kdebug("- start_code  %lx",     (long) current->mm->start_code);
 381         kdebug("- end_code    %lx",     (long) current->mm->end_code);
 382         kdebug("- start_data  %lx",     (long) current->mm->start_data);
 383         kdebug("- end_data    %lx",     (long) current->mm->end_data);
 384         kdebug("- start_brk   %lx",     (long) current->mm->start_brk);
 385         kdebug("- brk         %lx",     (long) current->mm->brk);
 386         kdebug("- start_stack %lx",     (long) current->mm->start_stack);
 387
 388 #ifdef ELF_FDPIC_PLAT_INIT
 389         /*
 390          * The ABI may specify that certain registers be set up in special
 391          * ways (on i386 %edx is the address of a DT_FINI function, for
 392          * example.  This macro performs whatever initialization to
 393          * the regs structure is required.
 394          */
 395         ELF_FDPIC_PLAT_INIT(regs,
 396                             exec_params.map_addr,
 397                             interp_params.map_addr,
 398                             interp_params.dynamic_addr ?: exec_params.dynamic_addr
 399                             );
 400 #endif
 401
 402         /* everything is now ready... get the userspace context ready to roll */
 403         start_thread(regs,
 404                      interp_params.entry_addr ?: exec_params.entry_addr,
 405                      current->mm->start_stack);
 406
 407         if (unlikely(current->ptrace & PT_PTRACED)) {
 408                 if (current->ptrace & PT_TRACE_EXEC)
 409                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 410                 else
 411                         send_sig(SIGTRAP, current, 0);
 412         }
 413
 414         retval = 0;
 415
 416 error:
 417         if (interpreter) {
 418                 allow_write_access(interpreter);
 419                 fput(interpreter);
 420         }
 421         if (interpreter_name)
 422                 kfree(interpreter_name);
 423         if (exec_params.phdrs)
 424                 kfree(exec_params.phdrs);
 425         if (exec_params.loadmap)
 426                 kfree(exec_params.loadmap);
 427         if (interp_params.phdrs)
 428                 kfree(interp_params.phdrs);
 429         if (interp_params.loadmap)
 430                 kfree(interp_params.loadmap);
 431         return retval;
 432
 433         /* unrecoverable error - kill the process */
 434  error_kill:
 435         send_sig(SIGSEGV, current, 0);
 436         goto error;
 437
 438 } /* end load_elf_fdpic_binary() */
 439
 440 /*****************************************************************************/
 441 /*
 442  * present useful information to the program
 443  */
 444 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 445                                    struct mm_struct *mm,
 446                                    struct elf_fdpic_params *exec_params,
 447                                    struct elf_fdpic_params *interp_params)
 448 {
 449         unsigned long sp, csp, nitems;
 450         elf_caddr_t *argv, *envp;
 451         size_t platform_len = 0, len;
 452         char *k_platform, *u_platform, *p;
 453         long hwcap;
 454         int loop;
 455
 456         /* we're going to shovel a whole load of stuff onto the stack */
 457 #ifdef CONFIG_MMU
 458         sp = bprm->p;
 459 #else
 460         sp = mm->start_stack;
 461
 462         /* stack the program arguments and environment */
 463         if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
 464                 return -EFAULT;
 465 #endif
 466
 467         /* get hold of platform and hardware capabilities masks for the machine
 468          * we are running on.  In some cases (Sparc), this info is impossible
 469          * to get, in others (i386) it is merely difficult.
 470          */
 471         hwcap = ELF_HWCAP;
 472         k_platform = ELF_PLATFORM;
 473
 474         if (k_platform) {
 475                 platform_len = strlen(k_platform) + 1;
 476                 sp -= platform_len;
 477                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 478                         return -EFAULT;
 479         }
 480
 481         u_platform = (char *) sp;
 482
 483 #if defined(__i386__) && defined(CONFIG_SMP)
 484         /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 485          * by the processes running on the same package. One thing we can do
 486          * is to shuffle the initial stack for them.
 487          *
 488          * the conditionals here are unneeded, but kept in to make the
 489          * code behaviour the same as pre change unless we have hyperthreaded
 490          * processors. This keeps Mr Marcelo Person happier but should be
 491          * removed for 2.5
 492          */
 493         if (smp_num_siblings > 1)
 494                 sp = sp - ((current->pid % 64) << 7);
 495 #endif
 496
 497         sp &= ~7UL;
 498
 499         /* stack the load map(s) */
 500         len = sizeof(struct elf32_fdpic_loadmap);
 501         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 502         sp = (sp - len) & ~7UL;
 503         exec_params->map_addr = sp;
 504
 505         if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
 506                 return -EFAULT;
 507
 508         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 509
 510         if (interp_params->loadmap) {
 511                 len = sizeof(struct elf32_fdpic_loadmap);
 512                 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
 513                 sp = (sp - len) & ~7UL;
 514                 interp_params->map_addr = sp;
 515
 516                 if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0)
 517                         return -EFAULT;
 518
 519                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 520         }
 521
 522         /* force 16 byte _final_ alignment here for generality */
 523 #define DLINFO_ITEMS 13
 524
 525         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
 526 #ifdef DLINFO_ARCH_ITEMS
 527         nitems += DLINFO_ARCH_ITEMS;
 528 #endif
 529
 530         csp = sp;
 531         sp -= nitems * 2 * sizeof(unsigned long);
 532         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 533         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 534         sp -= 1 * sizeof(unsigned long);                /* argc */
 535
 536         csp -= sp & 15UL;
 537         sp -= sp & 15UL;
 538
 539         /* put the ELF interpreter info on the stack */
 540 #define NEW_AUX_ENT(nr, id, val)                                                \
 541         do {                                                                    \
 542                 struct { unsigned long _id, _val; } *ent = (void *) csp;        \
 543                 __put_user((id), &ent[nr]._id);                                 \
 544                 __put_user((val), &ent[nr]._val);                               \
 545         } while (0)
 546
 547         csp -= 2 * sizeof(unsigned long);
 548         NEW_AUX_ENT(0, AT_NULL, 0);
 549         if (k_platform) {
 550                 csp -= 2 * sizeof(unsigned long);
 551                 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
 552         }
 553
 554         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 555         NEW_AUX_ENT( 0, AT_HWCAP,               hwcap);
 556         NEW_AUX_ENT( 1, AT_PAGESZ,              PAGE_SIZE);
 557         NEW_AUX_ENT( 2, AT_CLKTCK,              CLOCKS_PER_SEC);
 558         NEW_AUX_ENT( 3, AT_PHDR,                exec_params->ph_addr);
 559         NEW_AUX_ENT( 4, AT_PHENT,               sizeof(struct elf_phdr));
 560         NEW_AUX_ENT( 5, AT_PHNUM,               exec_params->hdr.e_phnum);
 561         NEW_AUX_ENT( 6, AT_BASE,                interp_params->elfhdr_addr);
 562         NEW_AUX_ENT( 7, AT_FLAGS,               0);
 563         NEW_AUX_ENT( 8, AT_ENTRY,               exec_params->entry_addr);
 564         NEW_AUX_ENT( 9, AT_UID,                 (elf_addr_t) current->uid);
 565         NEW_AUX_ENT(10, AT_EUID,                (elf_addr_t) current->euid);
 566         NEW_AUX_ENT(11, AT_GID,                 (elf_addr_t) current->gid);
 567         NEW_AUX_ENT(12, AT_EGID,                (elf_addr_t) current->egid);
 568
 569 #ifdef ARCH_DLINFO
 570         /* ARCH_DLINFO must come last so platform specific code can enforce
 571          * special alignment requirements on the AUXV if necessary (eg. PPC).
 572          */
 573         ARCH_DLINFO;
 574 #endif
 575 #undef NEW_AUX_ENT
 576
 577         /* allocate room for argv[] and envv[] */
 578         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 579         envp = (elf_caddr_t *) csp;
 580         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 581         argv = (elf_caddr_t *) csp;
 582
 583         /* stack argc */
 584         csp -= sizeof(unsigned long);
 585         __put_user(bprm->argc, (unsigned long *) csp);
 586
 587         if (csp != sp)
 588                 BUG();
 589
 590         /* fill in the argv[] array */
 591 #ifdef CONFIG_MMU
 592         current->mm->arg_start = bprm->p;
 593 #else
 594         current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 595 #endif
 596
 597         p = (char *) current->mm->arg_start;
 598         for (loop = bprm->argc; loop > 0; loop--) {
 599                 __put_user((elf_caddr_t) p, argv++);
 600                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 601                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 602                         return -EINVAL;
 603                 p += len;
 604         }
 605         __put_user(NULL, argv);
 606         current->mm->arg_end = (unsigned long) p;
 607
 608         /* fill in the envv[] array */
 609         current->mm->env_start = (unsigned long) p;
 610         for (loop = bprm->envc; loop > 0; loop--) {
 611                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
 612                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 613                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 614                         return -EINVAL;
 615                 p += len;
 616         }
 617         __put_user(NULL, envp);
 618         current->mm->env_end = (unsigned long) p;
 619
 620         mm->start_stack = (unsigned long) sp;
 621         return 0;
 622 } /* end create_elf_fdpic_tables() */
 623
 624 /*****************************************************************************/
 625 /*
 626  * transfer the program arguments and environment from the holding pages onto
 627  * the stack
 628  */
 629 #ifndef CONFIG_MMU
 630 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
 631 {
 632         unsigned long index, stop, sp;
 633         char *src;
 634         int ret = 0;
 635
 636         stop = bprm->p >> PAGE_SHIFT;
 637         sp = *_sp;
 638
 639         for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
 640                 src = kmap(bprm->page[index]);
 641                 sp -= PAGE_SIZE;
 642                 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
 643                         ret = -EFAULT;
 644                 kunmap(bprm->page[index]);
 645                 if (ret < 0)
 646                         goto out;
 647         }
 648
 649         *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
 650
 651  out:
 652         return ret;
 653 } /* end elf_fdpic_transfer_args_to_stack() */
 654 #endif
 655
 656 /*****************************************************************************/
 657 /*
 658  * load the appropriate binary image (executable or interpreter) into memory
 659  * - we assume no MMU is available
 660  * - if no other PIC bits are set in params->hdr->e_flags
 661  *   - we assume that the LOADable segments in the binary are independently relocatable
 662  *   - we assume R/O executable segments are shareable
 663  * - else
 664  *   - we assume the loadable parts of the image to require fixed displacement
 665  *   - the image is not shareable
 666  */
 667 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 668                               struct file *file,
 669                               struct mm_struct *mm,
 670                               const char *what)
 671 {
 672         struct elf32_fdpic_loadmap *loadmap;
 673 #ifdef CONFIG_MMU
 674         struct elf32_fdpic_loadseg *mseg;
 675 #endif
 676         struct elf32_fdpic_loadseg *seg;
 677         struct elf32_phdr *phdr;
 678         unsigned long load_addr, stop;
 679         unsigned nloads, tmp;
 680         size_t size;
 681         int loop, ret;
 682
 683         /* allocate a load map table */
 684         nloads = 0;
 685         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 686                 if (params->phdrs[loop].p_type == PT_LOAD)
 687                         nloads++;
 688
 689         if (nloads == 0)
 690                 return -ELIBBAD;
 691
 692         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 693         loadmap = kmalloc(size, GFP_KERNEL);
 694         if (!loadmap)
 695                 return -ENOMEM;
 696
 697         params->loadmap = loadmap;
 698         memset(loadmap, 0, size);
 699
 700         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 701         loadmap->nsegs = nloads;
 702
 703         load_addr = params->load_addr;
 704         seg = loadmap->segs;
 705
 706         /* map the requested LOADs into the memory space */
 707         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 708         case ELF_FDPIC_FLAG_CONSTDISP:
 709         case ELF_FDPIC_FLAG_CONTIGUOUS:
 710 #ifndef CONFIG_MMU
 711                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 712                 if (ret < 0)
 713                         return ret;
 714                 break;
 715 #endif
 716         default:
 717                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 718                 if (ret < 0)
 719                         return ret;
 720                 break;
 721         }
 722
 723         /* map the entry point */
 724         if (params->hdr.e_entry) {
 725                 seg = loadmap->segs;
 726                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 727                         if (params->hdr.e_entry >= seg->p_vaddr &&
 728                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
 729                             ) {
 730                                 params->entry_addr =
 731                                         (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
 732                                 break;
 733                         }
 734                 }
 735         }
 736
 737         /* determine where the program header table has wound up if mapped */
 738         stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
 739         phdr = params->phdrs;
 740
 741         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 742                 if (phdr->p_type != PT_LOAD)
 743                         continue;
 744
 745                 if (phdr->p_offset > params->hdr.e_phoff ||
 746                     phdr->p_offset + phdr->p_filesz < stop)
 747                         continue;
 748
 749                 seg = loadmap->segs;
 750                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 751                         if (phdr->p_vaddr >= seg->p_vaddr &&
 752                             phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
 753                             ) {
 754                                 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
 755                                         params->hdr.e_phoff - phdr->p_offset;
 756                                 break;
 757                         }
 758                 }
 759                 break;
 760         }
 761
 762         /* determine where the dynamic section has wound up if there is one */
 763         phdr = params->phdrs;
 764         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 765                 if (phdr->p_type != PT_DYNAMIC)
 766                         continue;
 767
 768                 seg = loadmap->segs;
 769                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 770                         if (phdr->p_vaddr >= seg->p_vaddr &&
 771                             phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
 772                             ) {
 773                                 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
 774
 775                                 /* check the dynamic section contains at least one item, and that
 776                                  * the last item is a NULL entry */
 777                                 if (phdr->p_memsz == 0 ||
 778                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 779                                         goto dynamic_error;
 780
 781                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 782                                 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
 783                                         goto dynamic_error;
 784                                 break;
 785                         }
 786                 }
 787                 break;
 788         }
 789
 790         /* now elide adjacent segments in the load map on MMU linux
 791          * - on uClinux the holes between may actually be filled with system stuff or stuff from
 792          *   other processes
 793          */
 794 #ifdef CONFIG_MMU
 795         nloads = loadmap->nsegs;
 796         mseg = loadmap->segs;
 797         seg = mseg + 1;
 798         for (loop = 1; loop < nloads; loop++) {
 799                 /* see if we have a candidate for merging */
 800                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 801                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 802                         if (load_addr == (seg->addr & PAGE_MASK)) {
 803                                 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
 804                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 805                                 mseg->p_memsz += seg->p_memsz;
 806                                 loadmap->nsegs--;
 807                                 continue;
 808                         }
 809                 }
 810
 811                 mseg++;
 812                 if (mseg != seg)
 813                         *mseg = *seg;
 814         }
 815 #endif
 816
 817         kdebug("Mapped Object [%s]:", what);
 818         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 819         kdebug("- entry    : %lx", params->entry_addr);
 820         kdebug("- PHDR[]   : %lx", params->ph_addr);
 821         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 822         seg = loadmap->segs;
 823         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 824                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 825                        loop,
 826                        seg->addr, seg->addr + seg->p_memsz - 1,
 827                        seg->p_vaddr, seg->p_memsz);
 828
 829         return 0;
 830
 831  dynamic_error:
 832         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 833                what, file->f_dentry->d_inode->i_ino);
 834         return -ELIBBAD;
 835 } /* end elf_fdpic_map_file() */
 836
 837 /*****************************************************************************/
 838 /*
 839  * map a file with constant displacement under uClinux
 840  */
 841 #ifndef CONFIG_MMU
 842 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
 843                                                    struct file *file,
 844                                                    struct mm_struct *mm)
 845 {
 846         struct elf32_fdpic_loadseg *seg;
 847         struct elf32_phdr *phdr;
 848         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 849         loff_t fpos;
 850         int loop, ret;
 851
 852         load_addr = params->load_addr;
 853         seg = params->loadmap->segs;
 854
 855         /* determine the bounds of the contiguous overall allocation we must make */
 856         phdr = params->phdrs;
 857         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 858                 if (params->phdrs[loop].p_type != PT_LOAD)
 859                         continue;
 860
 861                 if (base > phdr->p_vaddr)
 862                         base = phdr->p_vaddr;
 863                 if (top < phdr->p_vaddr + phdr->p_memsz)
 864                         top = phdr->p_vaddr + phdr->p_memsz;
 865         }
 866
 867         /* allocate one big anon block for everything */
 868         mflags = MAP_PRIVATE;
 869         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 870                 mflags |= MAP_EXECUTABLE;
 871
 872         down_write(&mm->mmap_sem);
 873         maddr = do_mmap(NULL, load_addr, top - base,
 874                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 875         up_write(&mm->mmap_sem);
 876         if (IS_ERR((void *) maddr))
 877                 return (int) maddr;
 878
 879         if (load_addr != 0)
 880                 load_addr += PAGE_ALIGN(top - base);
 881
 882         /* and then load the file segments into it */
 883         phdr = params->phdrs;
 884         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 885                 if (params->phdrs[loop].p_type != PT_LOAD)
 886                         continue;
 887
 888                 fpos = phdr->p_offset;
 889
 890                 seg->addr = maddr + (phdr->p_vaddr - base);
 891                 seg->p_vaddr = phdr->p_vaddr;
 892                 seg->p_memsz = phdr->p_memsz;
 893
 894                 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
 895                 if (ret < 0)
 896                         return ret;
 897
 898                 /* map the ELF header address if in this segment */
 899                 if (phdr->p_offset == 0)
 900                         params->elfhdr_addr = seg->addr;
 901
 902                 /* clear any space allocated but not loaded */
 903                 if (phdr->p_filesz < phdr->p_memsz)
 904                         clear_user((void *) (seg->addr + phdr->p_filesz),
 905                                    phdr->p_memsz - phdr->p_filesz);
 906
 907                 if (mm) {
 908                         if (phdr->p_flags & PF_X) {
 909                                 mm->start_code = seg->addr;
 910                                 mm->end_code = seg->addr + phdr->p_memsz;
 911                         }
 912                         else if (!mm->start_data) {
 913                                 mm->start_data = seg->addr;
 914 #ifndef CONFIG_MMU
 915                                 mm->end_data = seg->addr + phdr->p_memsz;
 916 #endif
 917                         }
 918
 919 #ifdef CONFIG_MMU
 920                         if (seg->addr + phdr->p_memsz > mm->end_data)
 921                                 mm->end_data = seg->addr + phdr->p_memsz;
 922 #endif
 923                 }
 924
 925                 seg++;
 926         }
 927
 928         return 0;
 929 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */
 930 #endif
 931
 932 /*****************************************************************************/
 933 /*
 934  * map a binary by direct mmap() of the individual PT_LOAD segments
 935  */
 936 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 937                                              struct file *file,
 938                                              struct mm_struct *mm)
 939 {
 940         struct elf32_fdpic_loadseg *seg;
 941         struct elf32_phdr *phdr;
 942         unsigned long load_addr, delta_vaddr;
 943         int loop, dvset;
 944
 945         load_addr = params->load_addr;
 946         delta_vaddr = 0;
 947         dvset = 0;
 948
 949         seg = params->loadmap->segs;
 950
 951         /* deal with each load segment separately */
 952         phdr = params->phdrs;
 953         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 954                 unsigned long maddr, disp, excess, excess1;
 955                 int prot = 0, flags;
 956
 957                 if (phdr->p_type != PT_LOAD)
 958                         continue;
 959
 960                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
 961                        (unsigned long) phdr->p_vaddr,
 962                        (unsigned long) phdr->p_offset,
 963                        (unsigned long) phdr->p_filesz,
 964                        (unsigned long) phdr->p_memsz);
 965
 966                 /* determine the mapping parameters */
 967                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
 968                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
 969                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
 970
 971                 flags = MAP_PRIVATE | MAP_DENYWRITE;
 972                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 973                         flags |= MAP_EXECUTABLE;
 974
 975                 maddr = 0;
 976
 977                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 978                 case ELF_FDPIC_FLAG_INDEPENDENT:
 979                         /* PT_LOADs are independently locatable */
 980                         break;
 981
 982                 case ELF_FDPIC_FLAG_HONOURVADDR:
 983                         /* the specified virtual address must be honoured */
 984                         maddr = phdr->p_vaddr;
 985                         flags |= MAP_FIXED;
 986                         break;
 987
 988                 case ELF_FDPIC_FLAG_CONSTDISP:
 989                         /* constant displacement
 990                          * - can be mapped anywhere, but must be mapped as a unit
 991                          */
 992                         if (!dvset) {
 993                                 maddr = load_addr;
 994                                 delta_vaddr = phdr->p_vaddr;
 995                                 dvset = 1;
 996                         }
 997                         else {
 998                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
 999                                 flags |= MAP_FIXED;
1000                         }
1001                         break;
1002
1003                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1004                         /* contiguity handled later */
1005                         break;
1006
1007                 default:
1008                         BUG();
1009                 }
1010
1011                 maddr &= PAGE_MASK;
1012
1013                 /* create the mapping */
1014                 disp = phdr->p_vaddr & ~PAGE_MASK;
1015                 down_write(&mm->mmap_sem);
1016                 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1017                                 phdr->p_offset - disp);
1018                 up_write(&mm->mmap_sem);
1019
1020                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1021                        loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1022                        maddr);
1023
1024                 if (IS_ERR((void *) maddr))
1025                         return (int) maddr;
1026
1027                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1028                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1029
1030                 seg->addr = maddr + disp;
1031                 seg->p_vaddr = phdr->p_vaddr;
1032                 seg->p_memsz = phdr->p_memsz;
1033
1034                 /* map the ELF header address if in this segment */
1035                 if (phdr->p_offset == 0)
1036                         params->elfhdr_addr = seg->addr;
1037
1038                 /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1039                 if (prot & PROT_WRITE && disp > 0) {
1040                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1041                         clear_user((void *) maddr, disp);
1042                         maddr += disp;
1043                 }
1044
1045                 /* clear any space allocated but not loaded
1046                  * - on uClinux we can just clear the lot
1047                  * - on MMU linux we'll get a SIGBUS beyond the last page
1048                  *   extant in the file
1049                  */
1050                 excess = phdr->p_memsz - phdr->p_filesz;
1051                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1052
1053 #ifdef CONFIG_MMU
1054
1055                 if (excess > excess1) {
1056                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1057                         unsigned long xmaddr;
1058
1059                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1060                         down_write(&mm->mmap_sem);
1061                         xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1062                         up_write(&mm->mmap_sem);
1063
1064                         kdebug("mmap[%d] <anon>"
1065                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1066                                loop, xaddr, excess - excess1, prot, flags, xmaddr);
1067
1068                         if (xmaddr != xaddr)
1069                                 return -ENOMEM;
1070                 }
1071
1072                 if (prot & PROT_WRITE && excess1 > 0) {
1073                         kdebug("clear[%d] ad=%lx sz=%lx",
1074                                loop, maddr + phdr->p_filesz, excess1);
1075                         clear_user((void *) maddr + phdr->p_filesz, excess1);
1076                 }
1077
1078 #else
1079                 if (excess > 0) {
1080                         kdebug("clear[%d] ad=%lx sz=%lx",
1081                                loop, maddr + phdr->p_filesz, excess);
1082                         clear_user((void *) maddr + phdr->p_filesz, excess);
1083                 }
1084 #endif
1085
1086                 if (mm) {
1087                         if (phdr->p_flags & PF_X) {
1088                                 mm->start_code = maddr;
1089                                 mm->end_code = maddr + phdr->p_memsz;
1090                         }
1091                         else if (!mm->start_data) {
1092                                 mm->start_data = maddr;
1093                                 mm->end_data = maddr + phdr->p_memsz;
1094                         }
1095                 }
1096
1097                 seg++;
1098         }
1099
1100         return 0;
1101 } /* end elf_fdpic_map_file_by_direct_mmap() */