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         // current->mm->rss = 0;
 303         vx_rsspages_sub(current->mm, current->mm->rss);
 304
 305 #ifdef CONFIG_MMU
 306         retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack);
 307         if (retval < 0) {
 308                 send_sig(SIGKILL, current, 0);
 309                 goto error_kill;
 310         }
 311 #endif
 312
 313         /* load the executable and interpreter into memory */
 314         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable");
 315         if (retval < 0)
 316                 goto error_kill;
 317
 318         if (interpreter_name) {
 319                 retval = elf_fdpic_map_file(&interp_params, interpreter,
 320                                             current->mm, "interpreter");
 321                 if (retval < 0) {
 322                         printk(KERN_ERR "Unable to load interpreter\n");
 323                         goto error_kill;
 324                 }
 325
 326                 allow_write_access(interpreter);
 327                 fput(interpreter);
 328                 interpreter = NULL;
 329         }
 330
 331 #ifdef CONFIG_MMU
 332         if (!current->mm->start_brk)
 333                 current->mm->start_brk = current->mm->end_data;
 334
 335         current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk);
 336
 337 #else
 338         /* create a stack and brk area big enough for everyone
 339          * - the brk heap starts at the bottom and works up
 340          * - the stack starts at the top and works down
 341          */
 342         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 343         if (stack_size < PAGE_SIZE * 2)
 344                 stack_size = PAGE_SIZE * 2;
 345
 346         down_write(&current->mm->mmap_sem);
 347         current->mm->start_brk = do_mmap(NULL,
 348                                          0,
 349                                          stack_size,
 350                                          PROT_READ | PROT_WRITE | PROT_EXEC,
 351                                          MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN,
 352                                          0);
 353
 354         if (IS_ERR((void *) current->mm->start_brk)) {
 355                 up_write(&current->mm->mmap_sem);
 356                 retval = current->mm->start_brk;
 357                 current->mm->start_brk = 0;
 358                 goto error_kill;
 359         }
 360
 361         if (do_mremap(current->mm->start_brk,
 362                       stack_size,
 363                       ksize((char *) current->mm->start_brk),
 364                       0, 0
 365                       ) == current->mm->start_brk
 366             )
 367                 stack_size = ksize((char *) current->mm->start_brk);
 368         up_write(&current->mm->mmap_sem);
 369
 370         current->mm->brk = current->mm->start_brk;
 371         current->mm->context.end_brk = current->mm->start_brk;
 372         current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
 373         current->mm->start_stack = current->mm->start_brk + stack_size;
 374 #endif
 375
 376         compute_creds(bprm);
 377         current->flags &= ~PF_FORKNOEXEC;
 378         if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0)
 379                 goto error_kill;
 380
 381         kdebug("- start_code  %lx",     (long) current->mm->start_code);
 382         kdebug("- end_code    %lx",     (long) current->mm->end_code);
 383         kdebug("- start_data  %lx",     (long) current->mm->start_data);
 384         kdebug("- end_data    %lx",     (long) current->mm->end_data);
 385         kdebug("- start_brk   %lx",     (long) current->mm->start_brk);
 386         kdebug("- brk         %lx",     (long) current->mm->brk);
 387         kdebug("- start_stack %lx",     (long) current->mm->start_stack);
 388
 389 #ifdef ELF_FDPIC_PLAT_INIT
 390         /*
 391          * The ABI may specify that certain registers be set up in special
 392          * ways (on i386 %edx is the address of a DT_FINI function, for
 393          * example.  This macro performs whatever initialization to
 394          * the regs structure is required.
 395          */
 396         ELF_FDPIC_PLAT_INIT(regs,
 397                             exec_params.map_addr,
 398                             interp_params.map_addr,
 399                             interp_params.dynamic_addr ?: exec_params.dynamic_addr
 400                             );
 401 #endif
 402
 403         /* everything is now ready... get the userspace context ready to roll */
 404         start_thread(regs,
 405                      interp_params.entry_addr ?: exec_params.entry_addr,
 406                      current->mm->start_stack);
 407
 408         if (unlikely(current->ptrace & PT_PTRACED)) {
 409                 if (current->ptrace & PT_TRACE_EXEC)
 410                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 411                 else
 412                         send_sig(SIGTRAP, current, 0);
 413         }
 414
 415         retval = 0;
 416
 417 error:
 418         if (interpreter) {
 419                 allow_write_access(interpreter);
 420                 fput(interpreter);
 421         }
 422         if (interpreter_name)
 423                 kfree(interpreter_name);
 424         if (exec_params.phdrs)
 425                 kfree(exec_params.phdrs);
 426         if (exec_params.loadmap)
 427                 kfree(exec_params.loadmap);
 428         if (interp_params.phdrs)
 429                 kfree(interp_params.phdrs);
 430         if (interp_params.loadmap)
 431                 kfree(interp_params.loadmap);
 432         return retval;
 433
 434         /* unrecoverable error - kill the process */
 435  error_kill:
 436         send_sig(SIGSEGV, current, 0);
 437         goto error;
 438
 439 } /* end load_elf_fdpic_binary() */
 440
 441 /*****************************************************************************/
 442 /*
 443  * present useful information to the program
 444  */
 445 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 446                                    struct mm_struct *mm,
 447                                    struct elf_fdpic_params *exec_params,
 448                                    struct elf_fdpic_params *interp_params)
 449 {
 450         unsigned long sp, csp, nitems;
 451         elf_caddr_t *argv, *envp;
 452         size_t platform_len = 0, len;
 453         char *k_platform, *u_platform, *p;
 454         long hwcap;
 455         int loop;
 456
 457         /* we're going to shovel a whole load of stuff onto the stack */
 458 #ifdef CONFIG_MMU
 459         sp = bprm->p;
 460 #else
 461         sp = mm->start_stack;
 462
 463         /* stack the program arguments and environment */
 464         if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
 465                 return -EFAULT;
 466 #endif
 467
 468         /* get hold of platform and hardware capabilities masks for the machine
 469          * we are running on.  In some cases (Sparc), this info is impossible
 470          * to get, in others (i386) it is merely difficult.
 471          */
 472         hwcap = ELF_HWCAP;
 473         k_platform = ELF_PLATFORM;
 474
 475         if (k_platform) {
 476                 platform_len = strlen(k_platform) + 1;
 477                 sp -= platform_len;
 478                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 479                         return -EFAULT;
 480         }
 481
 482         u_platform = (char *) sp;
 483
 484 #if defined(__i386__) && defined(CONFIG_SMP)
 485         /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 486          * by the processes running on the same package. One thing we can do
 487          * is to shuffle the initial stack for them.
 488          *
 489          * the conditionals here are unneeded, but kept in to make the
 490          * code behaviour the same as pre change unless we have hyperthreaded
 491          * processors. This keeps Mr Marcelo Person happier but should be
 492          * removed for 2.5
 493          */
 494         if (smp_num_siblings > 1)
 495                 sp = sp - ((current->pid % 64) << 7);
 496 #endif
 497
 498         sp &= ~7UL;
 499
 500         /* stack the load map(s) */
 501         len = sizeof(struct elf32_fdpic_loadmap);
 502         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 503         sp = (sp - len) & ~7UL;
 504         exec_params->map_addr = sp;
 505
 506         if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0)
 507                 return -EFAULT;
 508
 509         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 510
 511         if (interp_params->loadmap) {
 512                 len = sizeof(struct elf32_fdpic_loadmap);
 513                 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs;
 514                 sp = (sp - len) & ~7UL;
 515                 interp_params->map_addr = sp;
 516
 517                 if (copy_to_user((void *) sp, interp_params->loadmap, 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; } *ent = (void *) csp;        \
 544                 __put_user((id), &ent[nr]._id);                                 \
 545                 __put_user((val), &ent[nr]._val);                               \
 546         } while (0)
 547
 548         csp -= 2 * sizeof(unsigned long);
 549         NEW_AUX_ENT(0, AT_NULL, 0);
 550         if (k_platform) {
 551                 csp -= 2 * sizeof(unsigned long);
 552                 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
 553         }
 554
 555         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 556         NEW_AUX_ENT( 0, AT_HWCAP,               hwcap);
 557         NEW_AUX_ENT( 1, AT_PAGESZ,              PAGE_SIZE);
 558         NEW_AUX_ENT( 2, AT_CLKTCK,              CLOCKS_PER_SEC);
 559         NEW_AUX_ENT( 3, AT_PHDR,                exec_params->ph_addr);
 560         NEW_AUX_ENT( 4, AT_PHENT,               sizeof(struct elf_phdr));
 561         NEW_AUX_ENT( 5, AT_PHNUM,               exec_params->hdr.e_phnum);
 562         NEW_AUX_ENT( 6, AT_BASE,                interp_params->elfhdr_addr);
 563         NEW_AUX_ENT( 7, AT_FLAGS,               0);
 564         NEW_AUX_ENT( 8, AT_ENTRY,               exec_params->entry_addr);
 565         NEW_AUX_ENT( 9, AT_UID,                 (elf_addr_t) current->uid);
 566         NEW_AUX_ENT(10, AT_EUID,                (elf_addr_t) current->euid);
 567         NEW_AUX_ENT(11, AT_GID,                 (elf_addr_t) current->gid);
 568         NEW_AUX_ENT(12, AT_EGID,                (elf_addr_t) current->egid);
 569
 570 #ifdef ARCH_DLINFO
 571         /* ARCH_DLINFO must come last so platform specific code can enforce
 572          * special alignment requirements on the AUXV if necessary (eg. PPC).
 573          */
 574         ARCH_DLINFO;
 575 #endif
 576 #undef NEW_AUX_ENT
 577
 578         /* allocate room for argv[] and envv[] */
 579         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 580         envp = (elf_caddr_t *) csp;
 581         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 582         argv = (elf_caddr_t *) csp;
 583
 584         /* stack argc */
 585         csp -= sizeof(unsigned long);
 586         __put_user(bprm->argc, (unsigned long *) csp);
 587
 588         if (csp != sp)
 589                 BUG();
 590
 591         /* fill in the argv[] array */
 592 #ifdef CONFIG_MMU
 593         current->mm->arg_start = bprm->p;
 594 #else
 595         current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 596 #endif
 597
 598         p = (char *) current->mm->arg_start;
 599         for (loop = bprm->argc; loop > 0; loop--) {
 600                 __put_user((elf_caddr_t) p, argv++);
 601                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 602                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 603                         return -EINVAL;
 604                 p += len;
 605         }
 606         __put_user(NULL, argv);
 607         current->mm->arg_end = (unsigned long) p;
 608
 609         /* fill in the envv[] array */
 610         current->mm->env_start = (unsigned long) p;
 611         for (loop = bprm->envc; loop > 0; loop--) {
 612                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
 613                 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES);
 614                 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES)
 615                         return -EINVAL;
 616                 p += len;
 617         }
 618         __put_user(NULL, envp);
 619         current->mm->env_end = (unsigned long) p;
 620
 621         mm->start_stack = (unsigned long) sp;
 622         return 0;
 623 } /* end create_elf_fdpic_tables() */
 624
 625 /*****************************************************************************/
 626 /*
 627  * transfer the program arguments and environment from the holding pages onto
 628  * the stack
 629  */
 630 #ifndef CONFIG_MMU
 631 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp)
 632 {
 633         unsigned long index, stop, sp;
 634         char *src;
 635         int ret = 0;
 636
 637         stop = bprm->p >> PAGE_SHIFT;
 638         sp = *_sp;
 639
 640         for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
 641                 src = kmap(bprm->page[index]);
 642                 sp -= PAGE_SIZE;
 643                 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
 644                         ret = -EFAULT;
 645                 kunmap(bprm->page[index]);
 646                 if (ret < 0)
 647                         goto out;
 648         }
 649
 650         *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
 651
 652  out:
 653         return ret;
 654 } /* end elf_fdpic_transfer_args_to_stack() */
 655 #endif
 656
 657 /*****************************************************************************/
 658 /*
 659  * load the appropriate binary image (executable or interpreter) into memory
 660  * - we assume no MMU is available
 661  * - if no other PIC bits are set in params->hdr->e_flags
 662  *   - we assume that the LOADable segments in the binary are independently relocatable
 663  *   - we assume R/O executable segments are shareable
 664  * - else
 665  *   - we assume the loadable parts of the image to require fixed displacement
 666  *   - the image is not shareable
 667  */
 668 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 669                               struct file *file,
 670                               struct mm_struct *mm,
 671                               const char *what)
 672 {
 673         struct elf32_fdpic_loadmap *loadmap;
 674 #ifdef CONFIG_MMU
 675         struct elf32_fdpic_loadseg *mseg;
 676 #endif
 677         struct elf32_fdpic_loadseg *seg;
 678         struct elf32_phdr *phdr;
 679         unsigned long load_addr, stop;
 680         unsigned nloads, tmp;
 681         size_t size;
 682         int loop, ret;
 683
 684         /* allocate a load map table */
 685         nloads = 0;
 686         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 687                 if (params->phdrs[loop].p_type == PT_LOAD)
 688                         nloads++;
 689
 690         if (nloads == 0)
 691                 return -ELIBBAD;
 692
 693         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 694         loadmap = kmalloc(size, GFP_KERNEL);
 695         if (!loadmap)
 696                 return -ENOMEM;
 697
 698         params->loadmap = loadmap;
 699         memset(loadmap, 0, size);
 700
 701         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 702         loadmap->nsegs = nloads;
 703
 704         load_addr = params->load_addr;
 705         seg = loadmap->segs;
 706
 707         /* map the requested LOADs into the memory space */
 708         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 709         case ELF_FDPIC_FLAG_CONSTDISP:
 710         case ELF_FDPIC_FLAG_CONTIGUOUS:
 711 #ifndef CONFIG_MMU
 712                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 713                 if (ret < 0)
 714                         return ret;
 715                 break;
 716 #endif
 717         default:
 718                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 719                 if (ret < 0)
 720                         return ret;
 721                 break;
 722         }
 723
 724         /* map the entry point */
 725         if (params->hdr.e_entry) {
 726                 seg = loadmap->segs;
 727                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 728                         if (params->hdr.e_entry >= seg->p_vaddr &&
 729                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz
 730                             ) {
 731                                 params->entry_addr =
 732                                         (params->hdr.e_entry - seg->p_vaddr) + seg->addr;
 733                                 break;
 734                         }
 735                 }
 736         }
 737
 738         /* determine where the program header table has wound up if mapped */
 739         stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr);
 740         phdr = params->phdrs;
 741
 742         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 743                 if (phdr->p_type != PT_LOAD)
 744                         continue;
 745
 746                 if (phdr->p_offset > params->hdr.e_phoff ||
 747                     phdr->p_offset + phdr->p_filesz < stop)
 748                         continue;
 749
 750                 seg = loadmap->segs;
 751                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 752                         if (phdr->p_vaddr >= seg->p_vaddr &&
 753                             phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz
 754                             ) {
 755                                 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr +
 756                                         params->hdr.e_phoff - phdr->p_offset;
 757                                 break;
 758                         }
 759                 }
 760                 break;
 761         }
 762
 763         /* determine where the dynamic section has wound up if there is one */
 764         phdr = params->phdrs;
 765         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 766                 if (phdr->p_type != PT_DYNAMIC)
 767                         continue;
 768
 769                 seg = loadmap->segs;
 770                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 771                         if (phdr->p_vaddr >= seg->p_vaddr &&
 772                             phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz
 773                             ) {
 774                                 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr;
 775
 776                                 /* check the dynamic section contains at least one item, and that
 777                                  * the last item is a NULL entry */
 778                                 if (phdr->p_memsz == 0 ||
 779                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 780                                         goto dynamic_error;
 781
 782                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 783                                 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0)
 784                                         goto dynamic_error;
 785                                 break;
 786                         }
 787                 }
 788                 break;
 789         }
 790
 791         /* now elide adjacent segments in the load map on MMU linux
 792          * - on uClinux the holes between may actually be filled with system stuff or stuff from
 793          *   other processes
 794          */
 795 #ifdef CONFIG_MMU
 796         nloads = loadmap->nsegs;
 797         mseg = loadmap->segs;
 798         seg = mseg + 1;
 799         for (loop = 1; loop < nloads; loop++) {
 800                 /* see if we have a candidate for merging */
 801                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 802                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 803                         if (load_addr == (seg->addr & PAGE_MASK)) {
 804                                 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz);
 805                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 806                                 mseg->p_memsz += seg->p_memsz;
 807                                 loadmap->nsegs--;
 808                                 continue;
 809                         }
 810                 }
 811
 812                 mseg++;
 813                 if (mseg != seg)
 814                         *mseg = *seg;
 815         }
 816 #endif
 817
 818         kdebug("Mapped Object [%s]:", what);
 819         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 820         kdebug("- entry    : %lx", params->entry_addr);
 821         kdebug("- PHDR[]   : %lx", params->ph_addr);
 822         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 823         seg = loadmap->segs;
 824         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 825                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 826                        loop,
 827                        seg->addr, seg->addr + seg->p_memsz - 1,
 828                        seg->p_vaddr, seg->p_memsz);
 829
 830         return 0;
 831
 832  dynamic_error:
 833         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 834                what, file->f_dentry->d_inode->i_ino);
 835         return -ELIBBAD;
 836 } /* end elf_fdpic_map_file() */
 837
 838 /*****************************************************************************/
 839 /*
 840  * map a file with constant displacement under uClinux
 841  */
 842 #ifndef CONFIG_MMU
 843 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params,
 844                                                    struct file *file,
 845                                                    struct mm_struct *mm)
 846 {
 847         struct elf32_fdpic_loadseg *seg;
 848         struct elf32_phdr *phdr;
 849         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 850         loff_t fpos;
 851         int loop, ret;
 852
 853         load_addr = params->load_addr;
 854         seg = params->loadmap->segs;
 855
 856         /* determine the bounds of the contiguous overall allocation we must make */
 857         phdr = params->phdrs;
 858         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 859                 if (params->phdrs[loop].p_type != PT_LOAD)
 860                         continue;
 861
 862                 if (base > phdr->p_vaddr)
 863                         base = phdr->p_vaddr;
 864                 if (top < phdr->p_vaddr + phdr->p_memsz)
 865                         top = phdr->p_vaddr + phdr->p_memsz;
 866         }
 867
 868         /* allocate one big anon block for everything */
 869         mflags = MAP_PRIVATE;
 870         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 871                 mflags |= MAP_EXECUTABLE;
 872
 873         down_write(&mm->mmap_sem);
 874         maddr = do_mmap(NULL, load_addr, top - base,
 875                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 876         up_write(&mm->mmap_sem);
 877         if (IS_ERR((void *) maddr))
 878                 return (int) maddr;
 879
 880         if (load_addr != 0)
 881                 load_addr += PAGE_ALIGN(top - base);
 882
 883         /* and then load the file segments into it */
 884         phdr = params->phdrs;
 885         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 886                 if (params->phdrs[loop].p_type != PT_LOAD)
 887                         continue;
 888
 889                 fpos = phdr->p_offset;
 890
 891                 seg->addr = maddr + (phdr->p_vaddr - base);
 892                 seg->p_vaddr = phdr->p_vaddr;
 893                 seg->p_memsz = phdr->p_memsz;
 894
 895                 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos);
 896                 if (ret < 0)
 897                         return ret;
 898
 899                 /* map the ELF header address if in this segment */
 900                 if (phdr->p_offset == 0)
 901                         params->elfhdr_addr = seg->addr;
 902
 903                 /* clear any space allocated but not loaded */
 904                 if (phdr->p_filesz < phdr->p_memsz)
 905                         clear_user((void *) (seg->addr + phdr->p_filesz),
 906                                    phdr->p_memsz - phdr->p_filesz);
 907
 908                 if (mm) {
 909                         if (phdr->p_flags & PF_X) {
 910                                 mm->start_code = seg->addr;
 911                                 mm->end_code = seg->addr + phdr->p_memsz;
 912                         }
 913                         else if (!mm->start_data) {
 914                                 mm->start_data = seg->addr;
 915 #ifndef CONFIG_MMU
 916                                 mm->end_data = seg->addr + phdr->p_memsz;
 917 #endif
 918                         }
 919
 920 #ifdef CONFIG_MMU
 921                         if (seg->addr + phdr->p_memsz > mm->end_data)
 922                                 mm->end_data = seg->addr + phdr->p_memsz;
 923 #endif
 924                 }
 925
 926                 seg++;
 927         }
 928
 929         return 0;
 930 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */
 931 #endif
 932
 933 /*****************************************************************************/
 934 /*
 935  * map a binary by direct mmap() of the individual PT_LOAD segments
 936  */
 937 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 938                                              struct file *file,
 939                                              struct mm_struct *mm)
 940 {
 941         struct elf32_fdpic_loadseg *seg;
 942         struct elf32_phdr *phdr;
 943         unsigned long load_addr, delta_vaddr;
 944         int loop, dvset;
 945
 946         load_addr = params->load_addr;
 947         delta_vaddr = 0;
 948         dvset = 0;
 949
 950         seg = params->loadmap->segs;
 951
 952         /* deal with each load segment separately */
 953         phdr = params->phdrs;
 954         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 955                 unsigned long maddr, disp, excess, excess1;
 956                 int prot = 0, flags;
 957
 958                 if (phdr->p_type != PT_LOAD)
 959                         continue;
 960
 961                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
 962                        (unsigned long) phdr->p_vaddr,
 963                        (unsigned long) phdr->p_offset,
 964                        (unsigned long) phdr->p_filesz,
 965                        (unsigned long) phdr->p_memsz);
 966
 967                 /* determine the mapping parameters */
 968                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
 969                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
 970                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
 971
 972                 flags = MAP_PRIVATE | MAP_DENYWRITE;
 973                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 974                         flags |= MAP_EXECUTABLE;
 975
 976                 maddr = 0;
 977
 978                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 979                 case ELF_FDPIC_FLAG_INDEPENDENT:
 980                         /* PT_LOADs are independently locatable */
 981                         break;
 982
 983                 case ELF_FDPIC_FLAG_HONOURVADDR:
 984                         /* the specified virtual address must be honoured */
 985                         maddr = phdr->p_vaddr;
 986                         flags |= MAP_FIXED;
 987                         break;
 988
 989                 case ELF_FDPIC_FLAG_CONSTDISP:
 990                         /* constant displacement
 991                          * - can be mapped anywhere, but must be mapped as a unit
 992                          */
 993                         if (!dvset) {
 994                                 maddr = load_addr;
 995                                 delta_vaddr = phdr->p_vaddr;
 996                                 dvset = 1;
 997                         }
 998                         else {
 999                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1000                                 flags |= MAP_FIXED;
1001                         }
1002                         break;
1003
1004                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1005                         /* contiguity handled later */
1006                         break;
1007
1008                 default:
1009                         BUG();
1010                 }
1011
1012                 maddr &= PAGE_MASK;
1013
1014                 /* create the mapping */
1015                 disp = phdr->p_vaddr & ~PAGE_MASK;
1016                 down_write(&mm->mmap_sem);
1017                 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1018                                 phdr->p_offset - disp);
1019                 up_write(&mm->mmap_sem);
1020
1021                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1022                        loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp,
1023                        maddr);
1024
1025                 if (IS_ERR((void *) maddr))
1026                         return (int) maddr;
1027
1028                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS)
1029                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1030
1031                 seg->addr = maddr + disp;
1032                 seg->p_vaddr = phdr->p_vaddr;
1033                 seg->p_memsz = phdr->p_memsz;
1034
1035                 /* map the ELF header address if in this segment */
1036                 if (phdr->p_offset == 0)
1037                         params->elfhdr_addr = seg->addr;
1038
1039                 /* clear the bit between beginning of mapping and beginning of PT_LOAD */
1040                 if (prot & PROT_WRITE && disp > 0) {
1041                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1042                         clear_user((void *) maddr, disp);
1043                         maddr += disp;
1044                 }
1045
1046                 /* clear any space allocated but not loaded
1047                  * - on uClinux we can just clear the lot
1048                  * - on MMU linux we'll get a SIGBUS beyond the last page
1049                  *   extant in the file
1050                  */
1051                 excess = phdr->p_memsz - phdr->p_filesz;
1052                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1053
1054 #ifdef CONFIG_MMU
1055
1056                 if (excess > excess1) {
1057                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1058                         unsigned long xmaddr;
1059
1060                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1061                         down_write(&mm->mmap_sem);
1062                         xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0);
1063                         up_write(&mm->mmap_sem);
1064
1065                         kdebug("mmap[%d] <anon>"
1066                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1067                                loop, xaddr, excess - excess1, prot, flags, xmaddr);
1068
1069                         if (xmaddr != xaddr)
1070                                 return -ENOMEM;
1071                 }
1072
1073                 if (prot & PROT_WRITE && excess1 > 0) {
1074                         kdebug("clear[%d] ad=%lx sz=%lx",
1075                                loop, maddr + phdr->p_filesz, excess1);
1076                         clear_user((void *) maddr + phdr->p_filesz, excess1);
1077                 }
1078
1079 #else
1080                 if (excess > 0) {
1081                         kdebug("clear[%d] ad=%lx sz=%lx",
1082                                loop, maddr + phdr->p_filesz, excess);
1083                         clear_user((void *) maddr + phdr->p_filesz, excess);
1084                 }
1085 #endif
1086
1087                 if (mm) {
1088                         if (phdr->p_flags & PF_X) {
1089                                 mm->start_code = maddr;
1090                                 mm->end_code = maddr + phdr->p_memsz;
1091                         }
1092                         else if (!mm->start_data) {
1093                                 mm->start_data = maddr;
1094                                 mm->end_data = maddr + phdr->p_memsz;
1095                         }
1096                 }
1097
1098                 seg++;
1099         }
1100
1101         return 0;
1102 } /* end elf_fdpic_map_file_by_direct_mmap() */