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   1 /* binfmt_elf_fdpic.c: FDPIC ELF binary format
   2  *
   3  * Copyright (C) 2003, 2004, 2006 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 *, struct pt_regs *);
  54 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
  55 static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
  56                               struct mm_struct *, const char *);
  57
  58 static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
  59                                    struct elf_fdpic_params *,
  60                                    struct elf_fdpic_params *);
  61
  62 #ifndef CONFIG_MMU
  63 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *,
  64                                             unsigned long *);
  65 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
  66                                                    struct file *,
  67                                                    struct mm_struct *);
  68 #endif
  69
  70 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
  71                                              struct file *, struct mm_struct *);
  72
  73 static struct linux_binfmt elf_fdpic_format = {
  74         .module         = THIS_MODULE,
  75         .load_binary    = load_elf_fdpic_binary,
  76 //      .core_dump      = elf_fdpic_core_dump,
  77         .min_coredump   = ELF_EXEC_PAGESIZE,
  78 };
  79
  80 static int __init init_elf_fdpic_binfmt(void)
  81 {
  82         return register_binfmt(&elf_fdpic_format);
  83 }
  84
  85 static void __exit exit_elf_fdpic_binfmt(void)
  86 {
  87         unregister_binfmt(&elf_fdpic_format);
  88 }
  89
  90 module_init(init_elf_fdpic_binfmt);
  91 module_exit(exit_elf_fdpic_binfmt);
  92
  93 static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
  94 {
  95         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
  96                 return 0;
  97         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
  98                 return 0;
  99         if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
 100                 return 0;
 101         if (!file->f_op || !file->f_op->mmap)
 102                 return 0;
 103         return 1;
 104 }
 105
 106 /*****************************************************************************/
 107 /*
 108  * read the program headers table into memory
 109  */
 110 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
 111                                  struct file *file)
 112 {
 113         struct elf32_phdr *phdr;
 114         unsigned long size;
 115         int retval, loop;
 116
 117         if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 118                 return -ENOMEM;
 119         if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
 120                 return -ENOMEM;
 121
 122         size = params->hdr.e_phnum * sizeof(struct elf_phdr);
 123         params->phdrs = kmalloc(size, GFP_KERNEL);
 124         if (!params->phdrs)
 125                 return -ENOMEM;
 126
 127         retval = kernel_read(file, params->hdr.e_phoff,
 128                              (char *) params->phdrs, size);
 129         if (retval < 0)
 130                 return retval;
 131
 132         /* determine stack size for this binary */
 133         phdr = params->phdrs;
 134         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 135                 if (phdr->p_type != PT_GNU_STACK)
 136                         continue;
 137
 138                 if (phdr->p_flags & PF_X)
 139                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
 140                 else
 141                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
 142
 143                 params->stack_size = phdr->p_memsz;
 144                 break;
 145         }
 146
 147         return 0;
 148 }
 149
 150 /*****************************************************************************/
 151 /*
 152  * load an fdpic binary into various bits of memory
 153  */
 154 static int load_elf_fdpic_binary(struct linux_binprm *bprm,
 155                                  struct pt_regs *regs)
 156 {
 157         struct elf_fdpic_params exec_params, interp_params;
 158         struct elf_phdr *phdr;
 159         unsigned long stack_size, entryaddr;
 160 #ifndef CONFIG_MMU
 161         unsigned long fullsize;
 162 #endif
 163 #ifdef ELF_FDPIC_PLAT_INIT
 164         unsigned long dynaddr;
 165 #endif
 166         struct file *interpreter = NULL; /* to shut gcc up */
 167         char *interpreter_name = NULL;
 168         int executable_stack;
 169         int retval, i;
 170
 171         memset(&exec_params, 0, sizeof(exec_params));
 172         memset(&interp_params, 0, sizeof(interp_params));
 173
 174         exec_params.hdr = *(struct elfhdr *) bprm->buf;
 175         exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
 176
 177         /* check that this is a binary we know how to deal with */
 178         retval = -ENOEXEC;
 179         if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
 180                 goto error;
 181
 182         /* read the program header table */
 183         retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
 184         if (retval < 0)
 185                 goto error;
 186
 187         /* scan for a program header that specifies an interpreter */
 188         phdr = exec_params.phdrs;
 189
 190         for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
 191                 switch (phdr->p_type) {
 192                 case PT_INTERP:
 193                         retval = -ENOMEM;
 194                         if (phdr->p_filesz > PATH_MAX)
 195                                 goto error;
 196                         retval = -ENOENT;
 197                         if (phdr->p_filesz < 2)
 198                                 goto error;
 199
 200                         /* read the name of the interpreter into memory */
 201                         interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
 202                         if (!interpreter_name)
 203                                 goto error;
 204
 205                         retval = kernel_read(bprm->file,
 206                                              phdr->p_offset,
 207                                              interpreter_name,
 208                                              phdr->p_filesz);
 209                         if (retval < 0)
 210                                 goto error;
 211
 212                         retval = -ENOENT;
 213                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
 214                                 goto error;
 215
 216                         kdebug("Using ELF interpreter %s", interpreter_name);
 217
 218                         /* replace the program with the interpreter */
 219                         interpreter = open_exec(interpreter_name);
 220                         retval = PTR_ERR(interpreter);
 221                         if (IS_ERR(interpreter)) {
 222                                 interpreter = NULL;
 223                                 goto error;
 224                         }
 225
 226                         retval = kernel_read(interpreter, 0, bprm->buf,
 227                                              BINPRM_BUF_SIZE);
 228                         if (retval < 0)
 229                                 goto error;
 230
 231                         interp_params.hdr = *((struct elfhdr *) bprm->buf);
 232                         break;
 233
 234                 case PT_LOAD:
 235 #ifdef CONFIG_MMU
 236                         if (exec_params.load_addr == 0)
 237                                 exec_params.load_addr = phdr->p_vaddr;
 238 #endif
 239                         break;
 240                 }
 241
 242         }
 243
 244         if (elf_check_const_displacement(&exec_params.hdr))
 245                 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 246
 247         /* perform insanity checks on the interpreter */
 248         if (interpreter_name) {
 249                 retval = -ELIBBAD;
 250                 if (!is_elf_fdpic(&interp_params.hdr, interpreter))
 251                         goto error;
 252
 253                 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
 254
 255                 /* read the interpreter's program header table */
 256                 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
 257                 if (retval < 0)
 258                         goto error;
 259         }
 260
 261         stack_size = exec_params.stack_size;
 262         if (stack_size < interp_params.stack_size)
 263                 stack_size = interp_params.stack_size;
 264
 265         if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 266                 executable_stack = EXSTACK_ENABLE_X;
 267         else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 268                 executable_stack = EXSTACK_DISABLE_X;
 269         else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 270                 executable_stack = EXSTACK_ENABLE_X;
 271         else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 272                 executable_stack = EXSTACK_DISABLE_X;
 273         else
 274                 executable_stack = EXSTACK_DEFAULT;
 275
 276         retval = -ENOEXEC;
 277         if (stack_size == 0)
 278                 goto error;
 279
 280         if (elf_check_const_displacement(&interp_params.hdr))
 281                 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 282
 283         /* flush all traces of the currently running executable */
 284         retval = flush_old_exec(bprm);
 285         if (retval)
 286                 goto error;
 287
 288         /* there's now no turning back... the old userspace image is dead,
 289          * defunct, deceased, etc. after this point we have to exit via
 290          * error_kill */
 291         set_personality(PER_LINUX_FDPIC);
 292         set_binfmt(&elf_fdpic_format);
 293
 294         current->mm->start_code = 0;
 295         current->mm->end_code = 0;
 296         current->mm->start_stack = 0;
 297         current->mm->start_data = 0;
 298         current->mm->end_data = 0;
 299         current->mm->context.exec_fdpic_loadmap = 0;
 300         current->mm->context.interp_fdpic_loadmap = 0;
 301
 302         current->flags &= ~PF_FORKNOEXEC;
 303
 304 #ifdef CONFIG_MMU
 305         elf_fdpic_arch_lay_out_mm(&exec_params,
 306                                   &interp_params,
 307                                   &current->mm->start_stack,
 308                                   &current->mm->start_brk);
 309
 310         retval = setup_arg_pages(bprm, current->mm->start_stack,
 311                                  executable_stack);
 312         if (retval < 0) {
 313                 send_sig(SIGKILL, current, 0);
 314                 goto error_kill;
 315         }
 316 #endif
 317
 318         /* load the executable and interpreter into memory */
 319         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
 320                                     "executable");
 321         if (retval < 0)
 322                 goto error_kill;
 323
 324         if (interpreter_name) {
 325                 retval = elf_fdpic_map_file(&interp_params, interpreter,
 326                                             current->mm, "interpreter");
 327                 if (retval < 0) {
 328                         printk(KERN_ERR "Unable to load interpreter\n");
 329                         goto error_kill;
 330                 }
 331
 332                 allow_write_access(interpreter);
 333                 fput(interpreter);
 334                 interpreter = NULL;
 335         }
 336
 337 #ifdef CONFIG_MMU
 338         if (!current->mm->start_brk)
 339                 current->mm->start_brk = current->mm->end_data;
 340
 341         current->mm->brk = current->mm->start_brk =
 342                 PAGE_ALIGN(current->mm->start_brk);
 343
 344 #else
 345         /* create a stack and brk area big enough for everyone
 346          * - the brk heap starts at the bottom and works up
 347          * - the stack starts at the top and works down
 348          */
 349         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 350         if (stack_size < PAGE_SIZE * 2)
 351                 stack_size = PAGE_SIZE * 2;
 352
 353         down_write(&current->mm->mmap_sem);
 354         current->mm->start_brk = do_mmap(NULL, 0, stack_size,
 355                                          PROT_READ | PROT_WRITE | PROT_EXEC,
 356                                          MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
 357                                          0);
 358
 359         if (IS_ERR_VALUE(current->mm->start_brk)) {
 360                 up_write(&current->mm->mmap_sem);
 361                 retval = current->mm->start_brk;
 362                 current->mm->start_brk = 0;
 363                 goto error_kill;
 364         }
 365
 366         /* expand the stack mapping to use up the entire allocation granule */
 367         fullsize = ksize((char *) current->mm->start_brk);
 368         if (!IS_ERR_VALUE(do_mremap(current->mm->start_brk, stack_size,
 369                                     fullsize, 0, 0)))
 370                 stack_size = fullsize;
 371         up_write(&current->mm->mmap_sem);
 372
 373         current->mm->brk = current->mm->start_brk;
 374         current->mm->context.end_brk = current->mm->start_brk;
 375         current->mm->context.end_brk +=
 376                 (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
 377         current->mm->start_stack = current->mm->start_brk + stack_size;
 378 #endif
 379
 380         compute_creds(bprm);
 381         current->flags &= ~PF_FORKNOEXEC;
 382         if (create_elf_fdpic_tables(bprm, current->mm,
 383                                     &exec_params, &interp_params) < 0)
 384                 goto error_kill;
 385
 386         kdebug("- start_code  %lx", current->mm->start_code);
 387         kdebug("- end_code    %lx", current->mm->end_code);
 388         kdebug("- start_data  %lx", current->mm->start_data);
 389         kdebug("- end_data    %lx", current->mm->end_data);
 390         kdebug("- start_brk   %lx", current->mm->start_brk);
 391         kdebug("- brk         %lx", current->mm->brk);
 392         kdebug("- start_stack %lx", current->mm->start_stack);
 393
 394 #ifdef ELF_FDPIC_PLAT_INIT
 395         /*
 396          * The ABI may specify that certain registers be set up in special
 397          * ways (on i386 %edx is the address of a DT_FINI function, for
 398          * example.  This macro performs whatever initialization to
 399          * the regs structure is required.
 400          */
 401         dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
 402         ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
 403                             dynaddr);
 404 #endif
 405
 406         /* everything is now ready... get the userspace context ready to roll */
 407         entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
 408         start_thread(regs, entryaddr, current->mm->start_stack);
 409
 410         if (unlikely(current->ptrace & PT_PTRACED)) {
 411                 if (current->ptrace & PT_TRACE_EXEC)
 412                         ptrace_notify((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 413                 else
 414                         send_sig(SIGTRAP, current, 0);
 415         }
 416
 417         retval = 0;
 418
 419 error:
 420         if (interpreter) {
 421                 allow_write_access(interpreter);
 422                 fput(interpreter);
 423         }
 424         kfree(interpreter_name);
 425         kfree(exec_params.phdrs);
 426         kfree(exec_params.loadmap);
 427         kfree(interp_params.phdrs);
 428         kfree(interp_params.loadmap);
 429         return retval;
 430
 431         /* unrecoverable error - kill the process */
 432 error_kill:
 433         send_sig(SIGSEGV, current, 0);
 434         goto error;
 435
 436 }
 437
 438 /*****************************************************************************/
 439 /*
 440  * present useful information to the program
 441  */
 442 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 443                                    struct mm_struct *mm,
 444                                    struct elf_fdpic_params *exec_params,
 445                                    struct elf_fdpic_params *interp_params)
 446 {
 447         unsigned long sp, csp, nitems;
 448         elf_caddr_t __user *argv, *envp;
 449         size_t platform_len = 0, len;
 450         char *k_platform;
 451         char __user *u_platform, *p;
 452         long hwcap;
 453         int loop;
 454
 455         /* we're going to shovel a whole load of stuff onto the stack */
 456 #ifdef CONFIG_MMU
 457         sp = bprm->p;
 458 #else
 459         sp = mm->start_stack;
 460
 461         /* stack the program arguments and environment */
 462         if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
 463                 return -EFAULT;
 464 #endif
 465
 466         /* get hold of platform and hardware capabilities masks for the machine
 467          * we are running on.  In some cases (Sparc), this info is impossible
 468          * to get, in others (i386) it is merely difficult.
 469          */
 470         hwcap = ELF_HWCAP;
 471         k_platform = ELF_PLATFORM;
 472         u_platform = NULL;
 473
 474         if (k_platform) {
 475                 platform_len = strlen(k_platform) + 1;
 476                 sp -= platform_len;
 477                 u_platform = (char __user *) sp;
 478                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 479                         return -EFAULT;
 480         }
 481
 482 #if defined(__i386__) && defined(CONFIG_SMP)
 483         /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 484          * by the processes running on the same package. One thing we can do is
 485          * to shuffle the initial stack for them.
 486          *
 487          * the conditionals here are unneeded, but kept in to make the code
 488          * behaviour the same as pre change unless we have hyperthreaded
 489          * processors. This keeps Mr Marcelo Person happier but should be
 490          * removed for 2.5
 491          */
 492         if (smp_num_siblings > 1)
 493                 sp = sp - ((current->pid % 64) << 7);
 494 #endif
 495
 496         sp &= ~7UL;
 497
 498         /* stack the load map(s) */
 499         len = sizeof(struct elf32_fdpic_loadmap);
 500         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 501         sp = (sp - len) & ~7UL;
 502         exec_params->map_addr = sp;
 503
 504         if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
 505                 return -EFAULT;
 506
 507         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 508
 509         if (interp_params->loadmap) {
 510                 len = sizeof(struct elf32_fdpic_loadmap);
 511                 len += sizeof(struct elf32_fdpic_loadseg) *
 512                         interp_params->loadmap->nsegs;
 513                 sp = (sp - len) & ~7UL;
 514                 interp_params->map_addr = sp;
 515
 516                 if (copy_to_user((void __user *) sp, interp_params->loadmap,
 517                                  len) != 0)
 518                         return -EFAULT;
 519
 520                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 521         }
 522
 523         /* force 16 byte _final_ alignment here for generality */
 524 #define DLINFO_ITEMS 13
 525
 526         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
 527 #ifdef DLINFO_ARCH_ITEMS
 528         nitems += DLINFO_ARCH_ITEMS;
 529 #endif
 530
 531         csp = sp;
 532         sp -= nitems * 2 * sizeof(unsigned long);
 533         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 534         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 535         sp -= 1 * sizeof(unsigned long);                /* argc */
 536
 537         csp -= sp & 15UL;
 538         sp -= sp & 15UL;
 539
 540         /* put the ELF interpreter info on the stack */
 541 #define NEW_AUX_ENT(nr, id, val)                                        \
 542         do {                                                            \
 543                 struct { unsigned long _id, _val; } __user *ent;        \
 544                                                                         \
 545                 ent = (void __user *) csp;                              \
 546                 __put_user((id), &ent[nr]._id);                         \
 547                 __put_user((val), &ent[nr]._val);                       \
 548         } while (0)
 549
 550         csp -= 2 * sizeof(unsigned long);
 551         NEW_AUX_ENT(0, AT_NULL, 0);
 552         if (k_platform) {
 553                 csp -= 2 * sizeof(unsigned long);
 554                 NEW_AUX_ENT(0, AT_PLATFORM,
 555                             (elf_addr_t) (unsigned long) u_platform);
 556         }
 557
 558         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 559         NEW_AUX_ENT( 0, AT_HWCAP,       hwcap);
 560         NEW_AUX_ENT( 1, AT_PAGESZ,      PAGE_SIZE);
 561         NEW_AUX_ENT( 2, AT_CLKTCK,      CLOCKS_PER_SEC);
 562         NEW_AUX_ENT( 3, AT_PHDR,        exec_params->ph_addr);
 563         NEW_AUX_ENT( 4, AT_PHENT,       sizeof(struct elf_phdr));
 564         NEW_AUX_ENT( 5, AT_PHNUM,       exec_params->hdr.e_phnum);
 565         NEW_AUX_ENT( 6, AT_BASE,        interp_params->elfhdr_addr);
 566         NEW_AUX_ENT( 7, AT_FLAGS,       0);
 567         NEW_AUX_ENT( 8, AT_ENTRY,       exec_params->entry_addr);
 568         NEW_AUX_ENT( 9, AT_UID,         (elf_addr_t) current->uid);
 569         NEW_AUX_ENT(10, AT_EUID,        (elf_addr_t) current->euid);
 570         NEW_AUX_ENT(11, AT_GID,         (elf_addr_t) current->gid);
 571         NEW_AUX_ENT(12, AT_EGID,        (elf_addr_t) current->egid);
 572
 573 #ifdef ARCH_DLINFO
 574         /* ARCH_DLINFO must come last so platform specific code can enforce
 575          * special alignment requirements on the AUXV if necessary (eg. PPC).
 576          */
 577         ARCH_DLINFO;
 578 #endif
 579 #undef NEW_AUX_ENT
 580
 581         /* allocate room for argv[] and envv[] */
 582         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 583         envp = (elf_caddr_t __user *) csp;
 584         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 585         argv = (elf_caddr_t __user *) csp;
 586
 587         /* stack argc */
 588         csp -= sizeof(unsigned long);
 589         __put_user(bprm->argc, (unsigned long __user *) csp);
 590
 591         BUG_ON(csp != sp);
 592
 593         /* fill in the argv[] array */
 594 #ifdef CONFIG_MMU
 595         current->mm->arg_start = bprm->p;
 596 #else
 597         current->mm->arg_start = current->mm->start_stack -
 598                 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 599 #endif
 600
 601         p = (char __user *) current->mm->arg_start;
 602         for (loop = bprm->argc; loop > 0; loop--) {
 603                 __put_user((elf_caddr_t) p, argv++);
 604                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 605                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 606                         return -EINVAL;
 607                 p += len;
 608         }
 609         __put_user(NULL, argv);
 610         current->mm->arg_end = (unsigned long) p;
 611
 612         /* fill in the envv[] array */
 613         current->mm->env_start = (unsigned long) p;
 614         for (loop = bprm->envc; loop > 0; loop--) {
 615                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
 616                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 617                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 618                         return -EINVAL;
 619                 p += len;
 620         }
 621         __put_user(NULL, envp);
 622         current->mm->env_end = (unsigned long) p;
 623
 624         mm->start_stack = (unsigned long) sp;
 625         return 0;
 626 }
 627
 628 /*****************************************************************************/
 629 /*
 630  * transfer the program arguments and environment from the holding pages onto
 631  * the stack
 632  */
 633 #ifndef CONFIG_MMU
 634 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm,
 635                                             unsigned long *_sp)
 636 {
 637         unsigned long index, stop, sp;
 638         char *src;
 639         int ret = 0;
 640
 641         stop = bprm->p >> PAGE_SHIFT;
 642         sp = *_sp;
 643
 644         for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
 645                 src = kmap(bprm->page[index]);
 646                 sp -= PAGE_SIZE;
 647                 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
 648                         ret = -EFAULT;
 649                 kunmap(bprm->page[index]);
 650                 if (ret < 0)
 651                         goto out;
 652         }
 653
 654         *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
 655
 656 out:
 657         return ret;
 658 }
 659 #endif
 660
 661 /*****************************************************************************/
 662 /*
 663  * load the appropriate binary image (executable or interpreter) into memory
 664  * - we assume no MMU is available
 665  * - if no other PIC bits are set in params->hdr->e_flags
 666  *   - we assume that the LOADable segments in the binary are independently relocatable
 667  *   - we assume R/O executable segments are shareable
 668  * - else
 669  *   - we assume the loadable parts of the image to require fixed displacement
 670  *   - the image is not shareable
 671  */
 672 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 673                               struct file *file,
 674                               struct mm_struct *mm,
 675                               const char *what)
 676 {
 677         struct elf32_fdpic_loadmap *loadmap;
 678 #ifdef CONFIG_MMU
 679         struct elf32_fdpic_loadseg *mseg;
 680 #endif
 681         struct elf32_fdpic_loadseg *seg;
 682         struct elf32_phdr *phdr;
 683         unsigned long load_addr, stop;
 684         unsigned nloads, tmp;
 685         size_t size;
 686         int loop, ret;
 687
 688         /* allocate a load map table */
 689         nloads = 0;
 690         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 691                 if (params->phdrs[loop].p_type == PT_LOAD)
 692                         nloads++;
 693
 694         if (nloads == 0)
 695                 return -ELIBBAD;
 696
 697         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 698         loadmap = kmalloc(size, GFP_KERNEL);
 699         if (!loadmap)
 700                 return -ENOMEM;
 701
 702         params->loadmap = loadmap;
 703         memset(loadmap, 0, size);
 704
 705         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 706         loadmap->nsegs = nloads;
 707
 708         load_addr = params->load_addr;
 709         seg = loadmap->segs;
 710
 711         /* map the requested LOADs into the memory space */
 712         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 713         case ELF_FDPIC_FLAG_CONSTDISP:
 714         case ELF_FDPIC_FLAG_CONTIGUOUS:
 715 #ifndef CONFIG_MMU
 716                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 717                 if (ret < 0)
 718                         return ret;
 719                 break;
 720 #endif
 721         default:
 722                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 723                 if (ret < 0)
 724                         return ret;
 725                 break;
 726         }
 727
 728         /* map the entry point */
 729         if (params->hdr.e_entry) {
 730                 seg = loadmap->segs;
 731                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 732                         if (params->hdr.e_entry >= seg->p_vaddr &&
 733                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
 734                                 params->entry_addr =
 735                                         (params->hdr.e_entry - seg->p_vaddr) +
 736                                         seg->addr;
 737                                 break;
 738                         }
 739                 }
 740         }
 741
 742         /* determine where the program header table has wound up if mapped */
 743         stop = params->hdr.e_phoff;
 744         stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
 745         phdr = params->phdrs;
 746
 747         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 748                 if (phdr->p_type != PT_LOAD)
 749                         continue;
 750
 751                 if (phdr->p_offset > params->hdr.e_phoff ||
 752                     phdr->p_offset + phdr->p_filesz < stop)
 753                         continue;
 754
 755                 seg = loadmap->segs;
 756                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 757                         if (phdr->p_vaddr >= seg->p_vaddr &&
 758                             phdr->p_vaddr + phdr->p_filesz <=
 759                             seg->p_vaddr + seg->p_memsz) {
 760                                 params->ph_addr =
 761                                         (phdr->p_vaddr - seg->p_vaddr) +
 762                                         seg->addr +
 763                                         params->hdr.e_phoff - phdr->p_offset;
 764                                 break;
 765                         }
 766                 }
 767                 break;
 768         }
 769
 770         /* determine where the dynamic section has wound up if there is one */
 771         phdr = params->phdrs;
 772         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 773                 if (phdr->p_type != PT_DYNAMIC)
 774                         continue;
 775
 776                 seg = loadmap->segs;
 777                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 778                         if (phdr->p_vaddr >= seg->p_vaddr &&
 779                             phdr->p_vaddr + phdr->p_memsz <=
 780                             seg->p_vaddr + seg->p_memsz) {
 781                                 params->dynamic_addr =
 782                                         (phdr->p_vaddr - seg->p_vaddr) +
 783                                         seg->addr;
 784
 785                                 /* check the dynamic section contains at least
 786                                  * one item, and that the last item is a NULL
 787                                  * entry */
 788                                 if (phdr->p_memsz == 0 ||
 789                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 790                                         goto dynamic_error;
 791
 792                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 793                                 if (((Elf32_Dyn *)
 794                                      params->dynamic_addr)[tmp - 1].d_tag != 0)
 795                                         goto dynamic_error;
 796                                 break;
 797                         }
 798                 }
 799                 break;
 800         }
 801
 802         /* now elide adjacent segments in the load map on MMU linux
 803          * - on uClinux the holes between may actually be filled with system
 804          *   stuff or stuff from other processes
 805          */
 806 #ifdef CONFIG_MMU
 807         nloads = loadmap->nsegs;
 808         mseg = loadmap->segs;
 809         seg = mseg + 1;
 810         for (loop = 1; loop < nloads; loop++) {
 811                 /* see if we have a candidate for merging */
 812                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 813                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 814                         if (load_addr == (seg->addr & PAGE_MASK)) {
 815                                 mseg->p_memsz +=
 816                                         load_addr -
 817                                         (mseg->addr + mseg->p_memsz);
 818                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 819                                 mseg->p_memsz += seg->p_memsz;
 820                                 loadmap->nsegs--;
 821                                 continue;
 822                         }
 823                 }
 824
 825                 mseg++;
 826                 if (mseg != seg)
 827                         *mseg = *seg;
 828         }
 829 #endif
 830
 831         kdebug("Mapped Object [%s]:", what);
 832         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 833         kdebug("- entry    : %lx", params->entry_addr);
 834         kdebug("- PHDR[]   : %lx", params->ph_addr);
 835         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 836         seg = loadmap->segs;
 837         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 838                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 839                        loop,
 840                        seg->addr, seg->addr + seg->p_memsz - 1,
 841                        seg->p_vaddr, seg->p_memsz);
 842
 843         return 0;
 844
 845 dynamic_error:
 846         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 847                what, file->f_dentry->d_inode->i_ino);
 848         return -ELIBBAD;
 849 }
 850
 851 /*****************************************************************************/
 852 /*
 853  * map a file with constant displacement under uClinux
 854  */
 855 #ifndef CONFIG_MMU
 856 static int elf_fdpic_map_file_constdisp_on_uclinux(
 857         struct elf_fdpic_params *params,
 858         struct file *file,
 859         struct mm_struct *mm)
 860 {
 861         struct elf32_fdpic_loadseg *seg;
 862         struct elf32_phdr *phdr;
 863         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 864         loff_t fpos;
 865         int loop, ret;
 866
 867         load_addr = params->load_addr;
 868         seg = params->loadmap->segs;
 869
 870         /* determine the bounds of the contiguous overall allocation we must
 871          * make */
 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                 if (base > phdr->p_vaddr)
 878                         base = phdr->p_vaddr;
 879                 if (top < phdr->p_vaddr + phdr->p_memsz)
 880                         top = phdr->p_vaddr + phdr->p_memsz;
 881         }
 882
 883         /* allocate one big anon block for everything */
 884         mflags = MAP_PRIVATE;
 885         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 886                 mflags |= MAP_EXECUTABLE;
 887
 888         down_write(&mm->mmap_sem);
 889         maddr = do_mmap(NULL, load_addr, top - base,
 890                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 891         up_write(&mm->mmap_sem);
 892         if (IS_ERR_VALUE(maddr))
 893                 return (int) maddr;
 894
 895         if (load_addr != 0)
 896                 load_addr += PAGE_ALIGN(top - base);
 897
 898         /* and then load the file segments into it */
 899         phdr = params->phdrs;
 900         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 901                 if (params->phdrs[loop].p_type != PT_LOAD)
 902                         continue;
 903
 904                 fpos = phdr->p_offset;
 905
 906                 seg->addr = maddr + (phdr->p_vaddr - base);
 907                 seg->p_vaddr = phdr->p_vaddr;
 908                 seg->p_memsz = phdr->p_memsz;
 909
 910                 ret = file->f_op->read(file, (void *) seg->addr,
 911                                        phdr->p_filesz, &fpos);
 912                 if (ret < 0)
 913                         return ret;
 914
 915                 /* map the ELF header address if in this segment */
 916                 if (phdr->p_offset == 0)
 917                         params->elfhdr_addr = seg->addr;
 918
 919                 /* clear any space allocated but not loaded */
 920                 if (phdr->p_filesz < phdr->p_memsz)
 921                         clear_user((void *) (seg->addr + phdr->p_filesz),
 922                                    phdr->p_memsz - phdr->p_filesz);
 923
 924                 if (mm) {
 925                         if (phdr->p_flags & PF_X) {
 926                                 mm->start_code = seg->addr;
 927                                 mm->end_code = seg->addr + phdr->p_memsz;
 928                         } else if (!mm->start_data) {
 929                                 mm->start_data = seg->addr;
 930 #ifndef CONFIG_MMU
 931                                 mm->end_data = seg->addr + phdr->p_memsz;
 932 #endif
 933                         }
 934
 935 #ifdef CONFIG_MMU
 936                         if (seg->addr + phdr->p_memsz > mm->end_data)
 937                                 mm->end_data = seg->addr + phdr->p_memsz;
 938 #endif
 939                 }
 940
 941                 seg++;
 942         }
 943
 944         return 0;
 945 }
 946 #endif
 947
 948 /*****************************************************************************/
 949 /*
 950  * map a binary by direct mmap() of the individual PT_LOAD segments
 951  */
 952 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 953                                              struct file *file,
 954                                              struct mm_struct *mm)
 955 {
 956         struct elf32_fdpic_loadseg *seg;
 957         struct elf32_phdr *phdr;
 958         unsigned long load_addr, delta_vaddr;
 959         int loop, dvset;
 960
 961         load_addr = params->load_addr;
 962         delta_vaddr = 0;
 963         dvset = 0;
 964
 965         seg = params->loadmap->segs;
 966
 967         /* deal with each load segment separately */
 968         phdr = params->phdrs;
 969         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 970                 unsigned long maddr, disp, excess, excess1;
 971                 int prot = 0, flags;
 972
 973                 if (phdr->p_type != PT_LOAD)
 974                         continue;
 975
 976                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
 977                        (unsigned long) phdr->p_vaddr,
 978                        (unsigned long) phdr->p_offset,
 979                        (unsigned long) phdr->p_filesz,
 980                        (unsigned long) phdr->p_memsz);
 981
 982                 /* determine the mapping parameters */
 983                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
 984                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
 985                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
 986
 987                 flags = MAP_PRIVATE | MAP_DENYWRITE;
 988                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 989                         flags |= MAP_EXECUTABLE;
 990
 991                 maddr = 0;
 992
 993                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 994                 case ELF_FDPIC_FLAG_INDEPENDENT:
 995                         /* PT_LOADs are independently locatable */
 996                         break;
 997
 998                 case ELF_FDPIC_FLAG_HONOURVADDR:
 999                         /* the specified virtual address must be honoured */
1000                         maddr = phdr->p_vaddr;
1001                         flags |= MAP_FIXED;
1002                         break;
1003
1004                 case ELF_FDPIC_FLAG_CONSTDISP:
1005                         /* constant displacement
1006                          * - can be mapped anywhere, but must be mapped as a
1007                          *   unit
1008                          */
1009                         if (!dvset) {
1010                                 maddr = load_addr;
1011                                 delta_vaddr = phdr->p_vaddr;
1012                                 dvset = 1;
1013                         } else {
1014                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1015                                 flags |= MAP_FIXED;
1016                         }
1017                         break;
1018
1019                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1020                         /* contiguity handled later */
1021                         break;
1022
1023                 default:
1024                         BUG();
1025                 }
1026
1027                 maddr &= PAGE_MASK;
1028
1029                 /* create the mapping */
1030                 disp = phdr->p_vaddr & ~PAGE_MASK;
1031                 down_write(&mm->mmap_sem);
1032                 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1033                                 phdr->p_offset - disp);
1034                 up_write(&mm->mmap_sem);
1035
1036                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1037                        loop, phdr->p_memsz + disp, prot, flags,
1038                        phdr->p_offset - disp, maddr);
1039
1040                 if (IS_ERR_VALUE(maddr))
1041                         return (int) maddr;
1042
1043                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1044                     ELF_FDPIC_FLAG_CONTIGUOUS)
1045                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1046
1047                 seg->addr = maddr + disp;
1048                 seg->p_vaddr = phdr->p_vaddr;
1049                 seg->p_memsz = phdr->p_memsz;
1050
1051                 /* map the ELF header address if in this segment */
1052                 if (phdr->p_offset == 0)
1053                         params->elfhdr_addr = seg->addr;
1054
1055                 /* clear the bit between beginning of mapping and beginning of
1056                  * PT_LOAD */
1057                 if (prot & PROT_WRITE && disp > 0) {
1058                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1059                         clear_user((void __user *) maddr, disp);
1060                         maddr += disp;
1061                 }
1062
1063                 /* clear any space allocated but not loaded
1064                  * - on uClinux we can just clear the lot
1065                  * - on MMU linux we'll get a SIGBUS beyond the last page
1066                  *   extant in the file
1067                  */
1068                 excess = phdr->p_memsz - phdr->p_filesz;
1069                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1070
1071 #ifdef CONFIG_MMU
1072                 if (excess > excess1) {
1073                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1074                         unsigned long xmaddr;
1075
1076                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1077                         down_write(&mm->mmap_sem);
1078                         xmaddr = do_mmap(NULL, xaddr, excess - excess1,
1079                                          prot, flags, 0);
1080                         up_write(&mm->mmap_sem);
1081
1082                         kdebug("mmap[%d] <anon>"
1083                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1084                                loop, xaddr, excess - excess1, prot, flags,
1085                                xmaddr);
1086
1087                         if (xmaddr != xaddr)
1088                                 return -ENOMEM;
1089                 }
1090
1091                 if (prot & PROT_WRITE && excess1 > 0) {
1092                         kdebug("clear[%d] ad=%lx sz=%lx",
1093                                loop, maddr + phdr->p_filesz, excess1);
1094                         clear_user((void __user *) maddr + phdr->p_filesz,
1095                                    excess1);
1096                 }
1097
1098 #else
1099                 if (excess > 0) {
1100                         kdebug("clear[%d] ad=%lx sz=%lx",
1101                                loop, maddr + phdr->p_filesz, excess);
1102                         clear_user((void *) maddr + phdr->p_filesz, excess);
1103                 }
1104 #endif
1105
1106                 if (mm) {
1107                         if (phdr->p_flags & PF_X) {
1108                                 mm->start_code = maddr;
1109                                 mm->end_code = maddr + phdr->p_memsz;
1110                         } else if (!mm->start_data) {
1111                                 mm->start_data = maddr;
1112                                 mm->end_data = maddr + phdr->p_memsz;
1113                         }
1114                 }
1115
1116                 seg++;
1117         }
1118
1119         return 0;
1120 }