fs/binfmt_elf.c

   1 /*
   2  * linux/fs/binfmt_elf.c
   3  *
   4  * These are the functions used to load ELF format executables as used
   5  * on SVr4 machines.  Information on the format may be found in the book
   6  * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
   7  * Tools".
   8  *
   9  * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/fs.h>
  15 #include <linux/stat.h>
  16 #include <linux/time.h>
  17 #include <linux/mm.h>
  18 #include <linux/mman.h>
  19 #include <linux/a.out.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/ptrace.h>
  27 #include <linux/slab.h>
  28 #include <linux/shm.h>
  29 #include <linux/personality.h>
  30 #include <linux/elfcore.h>
  31 #include <linux/init.h>
  32 #include <linux/highuid.h>
  33 #include <linux/smp.h>
  34 #include <linux/smp_lock.h>
  35 #include <linux/compiler.h>
  36 #include <linux/highmem.h>
  37 #include <linux/pagemap.h>
  38 #include <linux/security.h>
  39 #include <linux/syscalls.h>
  40 #include <linux/random.h>
  41 #include <linux/elf.h>
  42 #include <asm/uaccess.h>
  43 #include <asm/param.h>
  44 #include <asm/page.h>
  45
  46 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  47 static int load_elf_library(struct file *);
  48 static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int);
  49 extern int dump_fpu (struct pt_regs *, elf_fpregset_t *);
  50
  51 #ifndef elf_addr_t
  52 #define elf_addr_t unsigned long
  53 #endif
  54
  55 /*
  56  * If we don't support core dumping, then supply a NULL so we
  57  * don't even try.
  58  */
  59 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
  60 static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file);
  61 #else
  62 #define elf_core_dump   NULL
  63 #endif
  64
  65 #if ELF_EXEC_PAGESIZE > PAGE_SIZE
  66 #define ELF_MIN_ALIGN   ELF_EXEC_PAGESIZE
  67 #else
  68 #define ELF_MIN_ALIGN   PAGE_SIZE
  69 #endif
  70
  71 #ifndef ELF_CORE_EFLAGS
  72 #define ELF_CORE_EFLAGS 0
  73 #endif
  74
  75 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
  76 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
  77 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
  78
  79 static struct linux_binfmt elf_format = {
  80                 .module         = THIS_MODULE,
  81                 .load_binary    = load_elf_binary,
  82                 .load_shlib     = load_elf_library,
  83                 .core_dump      = elf_core_dump,
  84                 .min_coredump   = ELF_EXEC_PAGESIZE
  85 };
  86
  87 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
  88
  89 static int set_brk(unsigned long start, unsigned long end)
  90 {
  91         start = ELF_PAGEALIGN(start);
  92         end = ELF_PAGEALIGN(end);
  93         if (end > start) {
  94                 unsigned long addr;
  95                 down_write(&current->mm->mmap_sem);
  96                 addr = do_brk(start, end - start);
  97                 up_write(&current->mm->mmap_sem);
  98                 if (BAD_ADDR(addr))
  99                         return addr;
 100         }
 101         current->mm->start_brk = current->mm->brk = end;
 102         return 0;
 103 }
 104
 105 /* We need to explicitly zero any fractional pages
 106    after the data section (i.e. bss).  This would
 107    contain the junk from the file that should not
 108    be in memory
 109  */
 110 static int padzero(unsigned long elf_bss)
 111 {
 112         unsigned long nbyte;
 113
 114         nbyte = ELF_PAGEOFFSET(elf_bss);
 115         if (nbyte) {
 116                 nbyte = ELF_MIN_ALIGN - nbyte;
 117                 if (clear_user((void __user *) elf_bss, nbyte))
 118                         return -EFAULT;
 119         }
 120         return 0;
 121 }
 122
 123 /* Let's use some macros to make this stack manipulation a litle clearer */
 124 #ifdef CONFIG_STACK_GROWSUP
 125 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
 126 #define STACK_ROUND(sp, items) \
 127         ((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
 128 #define STACK_ALLOC(sp, len) ({ \
 129         elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
 130         old_sp; })
 131 #else
 132 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
 133 #define STACK_ROUND(sp, items) \
 134         (((unsigned long) (sp - items)) &~ 15UL)
 135 #define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
 136 #endif
 137
 138 static int
 139 create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
 140                 int interp_aout, unsigned long load_addr,
 141                 unsigned long interp_load_addr)
 142 {
 143         unsigned long p = bprm->p;
 144         int argc = bprm->argc;
 145         int envc = bprm->envc;
 146         elf_addr_t __user *argv;
 147         elf_addr_t __user *envp;
 148         elf_addr_t __user *sp;
 149         elf_addr_t __user *u_platform;
 150         const char *k_platform = ELF_PLATFORM;
 151         int items;
 152         elf_addr_t *elf_info;
 153         int ei_index = 0;
 154         struct task_struct *tsk = current;
 155
 156         /*
 157          * If this architecture has a platform capability string, copy it
 158          * to userspace.  In some cases (Sparc), this info is impossible
 159          * for userspace to get any other way, in others (i386) it is
 160          * merely difficult.
 161          */
 162         u_platform = NULL;
 163         if (k_platform) {
 164                 size_t len = strlen(k_platform) + 1;
 165
 166                 /*
 167                  * In some cases (e.g. Hyper-Threading), we want to avoid L1
 168                  * evictions by the processes running on the same package. One
 169                  * thing we can do is to shuffle the initial stack for them.
 170                  */
 171
 172                 p = arch_align_stack(p);
 173
 174                 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 175                 if (__copy_to_user(u_platform, k_platform, len))
 176                         return -EFAULT;
 177         }
 178
 179         /* Create the ELF interpreter info */
 180         elf_info = (elf_addr_t *)current->mm->saved_auxv;
 181 #define NEW_AUX_ENT(id, val) \
 182         do { \
 183                 elf_info[ei_index++] = id; \
 184                 elf_info[ei_index++] = val; \
 185         } while (0)
 186
 187 #ifdef ARCH_DLINFO
 188         /*
 189          * ARCH_DLINFO must come first so PPC can do its special alignment of
 190          * AUXV.
 191          */
 192         ARCH_DLINFO;
 193 #endif
 194         NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
 195         NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
 196         NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
 197         NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
 198         NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
 199         NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
 200         NEW_AUX_ENT(AT_BASE, interp_load_addr);
 201         NEW_AUX_ENT(AT_FLAGS, 0);
 202         NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
 203         NEW_AUX_ENT(AT_UID, tsk->uid);
 204         NEW_AUX_ENT(AT_EUID, tsk->euid);
 205         NEW_AUX_ENT(AT_GID, tsk->gid);
 206         NEW_AUX_ENT(AT_EGID, tsk->egid);
 207         NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
 208         if (k_platform) {
 209                 NEW_AUX_ENT(AT_PLATFORM,
 210                             (elf_addr_t)(unsigned long)u_platform);
 211         }
 212         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
 213                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
 214         }
 215 #undef NEW_AUX_ENT
 216         /* AT_NULL is zero; clear the rest too */
 217         memset(&elf_info[ei_index], 0,
 218                sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
 219
 220         /* And advance past the AT_NULL entry.  */
 221         ei_index += 2;
 222
 223         sp = STACK_ADD(p, ei_index);
 224
 225         items = (argc + 1) + (envc + 1);
 226         if (interp_aout) {
 227                 items += 3; /* a.out interpreters require argv & envp too */
 228         } else {
 229                 items += 1; /* ELF interpreters only put argc on the stack */
 230         }
 231         bprm->p = STACK_ROUND(sp, items);
 232
 233         /* Point sp at the lowest address on the stack */
 234 #ifdef CONFIG_STACK_GROWSUP
 235         sp = (elf_addr_t __user *)bprm->p - items - ei_index;
 236         bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
 237 #else
 238         sp = (elf_addr_t __user *)bprm->p;
 239 #endif
 240
 241         /* Now, let's put argc (and argv, envp if appropriate) on the stack */
 242         if (__put_user(argc, sp++))
 243                 return -EFAULT;
 244         if (interp_aout) {
 245                 argv = sp + 2;
 246                 envp = argv + argc + 1;
 247                 __put_user((elf_addr_t)(unsigned long)argv, sp++);
 248                 __put_user((elf_addr_t)(unsigned long)envp, sp++);
 249         } else {
 250                 argv = sp;
 251                 envp = argv + argc + 1;
 252         }
 253
 254         /* Populate argv and envp */
 255         p = current->mm->arg_end = current->mm->arg_start;
 256         while (argc-- > 0) {
 257                 size_t len;
 258                 __put_user((elf_addr_t)p, argv++);
 259                 len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES);
 260                 if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
 261                         return 0;
 262                 p += len;
 263         }
 264         if (__put_user(0, argv))
 265                 return -EFAULT;
 266         current->mm->arg_end = current->mm->env_start = p;
 267         while (envc-- > 0) {
 268                 size_t len;
 269                 __put_user((elf_addr_t)p, envp++);
 270                 len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES);
 271                 if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
 272                         return 0;
 273                 p += len;
 274         }
 275         if (__put_user(0, envp))
 276                 return -EFAULT;
 277         current->mm->env_end = p;
 278
 279         /* Put the elf_info on the stack in the right place.  */
 280         sp = (elf_addr_t __user *)envp + 1;
 281         if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
 282                 return -EFAULT;
 283         return 0;
 284 }
 285
 286 #ifndef elf_map
 287
 288 static unsigned long elf_map(struct file *filep, unsigned long addr,
 289                 struct elf_phdr *eppnt, int prot, int type)
 290 {
 291         unsigned long map_addr;
 292         unsigned long pageoffset = ELF_PAGEOFFSET(eppnt->p_vaddr);
 293
 294         down_write(&current->mm->mmap_sem);
 295         /* mmap() will return -EINVAL if given a zero size, but a
 296          * segment with zero filesize is perfectly valid */
 297         if (eppnt->p_filesz + pageoffset)
 298                 map_addr = do_mmap(filep, ELF_PAGESTART(addr),
 299                                    eppnt->p_filesz + pageoffset, prot, type,
 300                                    eppnt->p_offset - pageoffset);
 301         else
 302                 map_addr = ELF_PAGESTART(addr);
 303         up_write(&current->mm->mmap_sem);
 304         return(map_addr);
 305 }
 306
 307 #endif /* !elf_map */
 308
 309 /* This is much more generalized than the library routine read function,
 310    so we keep this separate.  Technically the library read function
 311    is only provided so that we can read a.out libraries that have
 312    an ELF header */
 313
 314 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 315                 struct file *interpreter, unsigned long *interp_load_addr)
 316 {
 317         struct elf_phdr *elf_phdata;
 318         struct elf_phdr *eppnt;
 319         unsigned long load_addr = 0;
 320         int load_addr_set = 0;
 321         unsigned long last_bss = 0, elf_bss = 0;
 322         unsigned long error = ~0UL;
 323         int retval, i, size;
 324
 325         /* First of all, some simple consistency checks */
 326         if (interp_elf_ex->e_type != ET_EXEC &&
 327             interp_elf_ex->e_type != ET_DYN)
 328                 goto out;
 329         if (!elf_check_arch(interp_elf_ex))
 330                 goto out;
 331         if (!interpreter->f_op || !interpreter->f_op->mmap)
 332                 goto out;
 333
 334         /*
 335          * If the size of this structure has changed, then punt, since
 336          * we will be doing the wrong thing.
 337          */
 338         if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
 339                 goto out;
 340         if (interp_elf_ex->e_phnum < 1 ||
 341                 interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
 342                 goto out;
 343
 344         /* Now read in all of the header information */
 345         size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
 346         if (size > ELF_MIN_ALIGN)
 347                 goto out;
 348         elf_phdata = kmalloc(size, GFP_KERNEL);
 349         if (!elf_phdata)
 350                 goto out;
 351
 352         retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
 353                              (char *)elf_phdata,size);
 354         error = -EIO;
 355         if (retval != size) {
 356                 if (retval < 0)
 357                         error = retval;
 358                 goto out_close;
 359         }
 360
 361         eppnt = elf_phdata;
 362         for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
 363                 if (eppnt->p_type == PT_LOAD) {
 364                         int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
 365                         int elf_prot = 0;
 366                         unsigned long vaddr = 0;
 367                         unsigned long k, map_addr;
 368
 369                         if (eppnt->p_flags & PF_R)
 370                                 elf_prot = PROT_READ;
 371                         if (eppnt->p_flags & PF_W)
 372                                 elf_prot |= PROT_WRITE;
 373                         if (eppnt->p_flags & PF_X)
 374                                 elf_prot |= PROT_EXEC;
 375                         vaddr = eppnt->p_vaddr;
 376                         if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
 377                                 elf_type |= MAP_FIXED;
 378
 379                         map_addr = elf_map(interpreter, load_addr + vaddr,
 380                                            eppnt, elf_prot, elf_type);
 381                         error = map_addr;
 382                         if (BAD_ADDR(map_addr))
 383                                 goto out_close;
 384
 385                         if (!load_addr_set &&
 386                             interp_elf_ex->e_type == ET_DYN) {
 387                                 load_addr = map_addr - ELF_PAGESTART(vaddr);
 388                                 load_addr_set = 1;
 389                         }
 390
 391                         /*
 392                          * Check to see if the section's size will overflow the
 393                          * allowed task size. Note that p_filesz must always be
 394                          * <= p_memsize so it's only necessary to check p_memsz.
 395                          */
 396                         k = load_addr + eppnt->p_vaddr;
 397                         if (BAD_ADDR(k) ||
 398                             eppnt->p_filesz > eppnt->p_memsz ||
 399                             eppnt->p_memsz > TASK_SIZE ||
 400                             TASK_SIZE - eppnt->p_memsz < k) {
 401                                 error = -ENOMEM;
 402                                 goto out_close;
 403                         }
 404
 405                         /*
 406                          * Find the end of the file mapping for this phdr, and
 407                          * keep track of the largest address we see for this.
 408                          */
 409                         k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
 410                         if (k > elf_bss)
 411                                 elf_bss = k;
 412
 413                         /*
 414                          * Do the same thing for the memory mapping - between
 415                          * elf_bss and last_bss is the bss section.
 416                          */
 417                         k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
 418                         if (k > last_bss)
 419                                 last_bss = k;
 420                 }
 421         }
 422
 423         /*
 424          * Now fill out the bss section.  First pad the last page up
 425          * to the page boundary, and then perform a mmap to make sure
 426          * that there are zero-mapped pages up to and including the
 427          * last bss page.
 428          */
 429         if (padzero(elf_bss)) {
 430                 error = -EFAULT;
 431                 goto out_close;
 432         }
 433
 434         /* What we have mapped so far */
 435         elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
 436
 437         /* Map the last of the bss segment */
 438         if (last_bss > elf_bss) {
 439                 down_write(&current->mm->mmap_sem);
 440                 error = do_brk(elf_bss, last_bss - elf_bss);
 441                 up_write(&current->mm->mmap_sem);
 442                 if (BAD_ADDR(error))
 443                         goto out_close;
 444         }
 445
 446         *interp_load_addr = load_addr;
 447         error = ((unsigned long)interp_elf_ex->e_entry) + load_addr;
 448
 449 out_close:
 450         kfree(elf_phdata);
 451 out:
 452         return error;
 453 }
 454
 455 static unsigned long load_aout_interp(struct exec *interp_ex,
 456                 struct file *interpreter)
 457 {
 458         unsigned long text_data, elf_entry = ~0UL;
 459         char __user * addr;
 460         loff_t offset;
 461
 462         current->mm->end_code = interp_ex->a_text;
 463         text_data = interp_ex->a_text + interp_ex->a_data;
 464         current->mm->end_data = text_data;
 465         current->mm->brk = interp_ex->a_bss + text_data;
 466
 467         switch (N_MAGIC(*interp_ex)) {
 468         case OMAGIC:
 469                 offset = 32;
 470                 addr = (char __user *)0;
 471                 break;
 472         case ZMAGIC:
 473         case QMAGIC:
 474                 offset = N_TXTOFF(*interp_ex);
 475                 addr = (char __user *)N_TXTADDR(*interp_ex);
 476                 break;
 477         default:
 478                 goto out;
 479         }
 480
 481         down_write(&current->mm->mmap_sem);
 482         do_brk(0, text_data);
 483         up_write(&current->mm->mmap_sem);
 484         if (!interpreter->f_op || !interpreter->f_op->read)
 485                 goto out;
 486         if (interpreter->f_op->read(interpreter, addr, text_data, &offset) < 0)
 487                 goto out;
 488         flush_icache_range((unsigned long)addr,
 489                            (unsigned long)addr + text_data);
 490
 491         down_write(&current->mm->mmap_sem);
 492         do_brk(ELF_PAGESTART(text_data + ELF_MIN_ALIGN - 1),
 493                 interp_ex->a_bss);
 494         up_write(&current->mm->mmap_sem);
 495         elf_entry = interp_ex->a_entry;
 496
 497 out:
 498         return elf_entry;
 499 }
 500
 501 /*
 502  * These are the functions used to load ELF style executables and shared
 503  * libraries.  There is no binary dependent code anywhere else.
 504  */
 505
 506 #define INTERPRETER_NONE 0
 507 #define INTERPRETER_AOUT 1
 508 #define INTERPRETER_ELF 2
 509
 510 #ifndef STACK_RND_MASK
 511 #define STACK_RND_MASK 0x7ff            /* with 4K pages 8MB of VA */
 512 #endif
 513
 514 static unsigned long randomize_stack_top(unsigned long stack_top)
 515 {
 516         unsigned int random_variable = 0;
 517
 518         if ((current->flags & PF_RANDOMIZE) &&
 519                 !(current->personality & ADDR_NO_RANDOMIZE)) {
 520                 random_variable = get_random_int() & STACK_RND_MASK;
 521                 random_variable <<= PAGE_SHIFT;
 522         }
 523 #ifdef CONFIG_STACK_GROWSUP
 524         return PAGE_ALIGN(stack_top) + random_variable;
 525 #else
 526         return PAGE_ALIGN(stack_top) - random_variable;
 527 #endif
 528 }
 529
 530 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 531 {
 532         struct file *interpreter = NULL; /* to shut gcc up */
 533         unsigned long load_addr = 0, load_bias = 0;
 534         int load_addr_set = 0;
 535         char * elf_interpreter = NULL;
 536         unsigned int interpreter_type = INTERPRETER_NONE;
 537         unsigned char ibcs2_interpreter = 0;
 538         unsigned long error;
 539         struct elf_phdr *elf_ppnt, *elf_phdata;
 540         unsigned long elf_bss, elf_brk;
 541         int elf_exec_fileno;
 542         int retval, i;
 543         unsigned int size;
 544         unsigned long elf_entry, interp_load_addr = 0;
 545         unsigned long start_code, end_code, start_data, end_data;
 546         unsigned long reloc_func_desc = 0;
 547         char passed_fileno[6];
 548         struct files_struct *files;
 549         int have_pt_gnu_stack, executable_stack = EXSTACK_DEFAULT;
 550         unsigned long def_flags = 0;
 551         struct {
 552                 struct elfhdr elf_ex;
 553                 struct elfhdr interp_elf_ex;
 554                 struct exec interp_ex;
 555         } *loc;
 556
 557         loc = kmalloc(sizeof(*loc), GFP_KERNEL);
 558         if (!loc) {
 559                 retval = -ENOMEM;
 560                 goto out_ret;
 561         }
 562
 563         /* Get the exec-header */
 564         loc->elf_ex = *((struct elfhdr *)bprm->buf);
 565
 566         retval = -ENOEXEC;
 567         /* First of all, some simple consistency checks */
 568         if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 569                 goto out;
 570
 571         if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
 572                 goto out;
 573         if (!elf_check_arch(&loc->elf_ex))
 574                 goto out;
 575         if (!bprm->file->f_op||!bprm->file->f_op->mmap)
 576                 goto out;
 577
 578         /* Now read in all of the header information */
 579         if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
 580                 goto out;
 581         if (loc->elf_ex.e_phnum < 1 ||
 582                 loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
 583                 goto out;
 584         size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
 585         retval = -ENOMEM;
 586         elf_phdata = kmalloc(size, GFP_KERNEL);
 587         if (!elf_phdata)
 588                 goto out;
 589
 590         retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
 591                              (char *)elf_phdata, size);
 592         if (retval != size) {
 593                 if (retval >= 0)
 594                         retval = -EIO;
 595                 goto out_free_ph;
 596         }
 597
 598         files = current->files; /* Refcounted so ok */
 599         retval = unshare_files();
 600         if (retval < 0)
 601                 goto out_free_ph;
 602         if (files == current->files) {
 603                 put_files_struct(files);
 604                 files = NULL;
 605         }
 606
 607         /* exec will make our files private anyway, but for the a.out
 608            loader stuff we need to do it earlier */
 609         retval = get_unused_fd();
 610         if (retval < 0)
 611                 goto out_free_fh;
 612         get_file(bprm->file);
 613         fd_install(elf_exec_fileno = retval, bprm->file);
 614
 615         elf_ppnt = elf_phdata;
 616         elf_bss = 0;
 617         elf_brk = 0;
 618
 619         start_code = ~0UL;
 620         end_code = 0;
 621         start_data = 0;
 622         end_data = 0;
 623
 624         for (i = 0; i < loc->elf_ex.e_phnum; i++) {
 625                 if (elf_ppnt->p_type == PT_INTERP) {
 626                         /* This is the program interpreter used for
 627                          * shared libraries - for now assume that this
 628                          * is an a.out format binary
 629                          */
 630                         retval = -ENOEXEC;
 631                         if (elf_ppnt->p_filesz > PATH_MAX ||
 632                             elf_ppnt->p_filesz < 2)
 633                                 goto out_free_file;
 634
 635                         retval = -ENOMEM;
 636                         elf_interpreter = kmalloc(elf_ppnt->p_filesz,
 637                                                   GFP_KERNEL);
 638                         if (!elf_interpreter)
 639                                 goto out_free_file;
 640
 641                         retval = kernel_read(bprm->file, elf_ppnt->p_offset,
 642                                              elf_interpreter,
 643                                              elf_ppnt->p_filesz);
 644                         if (retval != elf_ppnt->p_filesz) {
 645                                 if (retval >= 0)
 646                                         retval = -EIO;
 647                                 goto out_free_interp;
 648                         }
 649                         /* make sure path is NULL terminated */
 650                         retval = -ENOEXEC;
 651                         if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
 652                                 goto out_free_interp;
 653
 654                         /* If the program interpreter is one of these two,
 655                          * then assume an iBCS2 image. Otherwise assume
 656                          * a native linux image.
 657                          */
 658                         if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 ||
 659                             strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0)
 660                                 ibcs2_interpreter = 1;
 661
 662                         /*
 663                          * The early SET_PERSONALITY here is so that the lookup
 664                          * for the interpreter happens in the namespace of the
 665                          * to-be-execed image.  SET_PERSONALITY can select an
 666                          * alternate root.
 667                          *
 668                          * However, SET_PERSONALITY is NOT allowed to switch
 669                          * this task into the new images's memory mapping
 670                          * policy - that is, TASK_SIZE must still evaluate to
 671                          * that which is appropriate to the execing application.
 672                          * This is because exit_mmap() needs to have TASK_SIZE
 673                          * evaluate to the size of the old image.
 674                          *
 675                          * So if (say) a 64-bit application is execing a 32-bit
 676                          * application it is the architecture's responsibility
 677                          * to defer changing the value of TASK_SIZE until the
 678                          * switch really is going to happen - do this in
 679                          * flush_thread().      - akpm
 680                          */
 681                         SET_PERSONALITY(loc->elf_ex, ibcs2_interpreter);
 682
 683                         interpreter = open_exec(elf_interpreter);
 684                         retval = PTR_ERR(interpreter);
 685                         if (IS_ERR(interpreter))
 686                                 goto out_free_interp;
 687                         retval = kernel_read(interpreter, 0, bprm->buf,
 688                                              BINPRM_BUF_SIZE);
 689                         if (retval != BINPRM_BUF_SIZE) {
 690                                 if (retval >= 0)
 691                                         retval = -EIO;
 692                                 goto out_free_dentry;
 693                         }
 694
 695                         /* Get the exec headers */
 696                         loc->interp_ex = *((struct exec *)bprm->buf);
 697                         loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
 698                         break;
 699                 }
 700                 elf_ppnt++;
 701         }
 702
 703         elf_ppnt = elf_phdata;
 704         for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
 705                 if (elf_ppnt->p_type == PT_GNU_STACK) {
 706                         if (elf_ppnt->p_flags & PF_X)
 707                                 executable_stack = EXSTACK_ENABLE_X;
 708                         else
 709                                 executable_stack = EXSTACK_DISABLE_X;
 710                         break;
 711                 }
 712         have_pt_gnu_stack = (i < loc->elf_ex.e_phnum);
 713
 714         /* Some simple consistency checks for the interpreter */
 715         if (elf_interpreter) {
 716                 interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;
 717
 718                 /* Now figure out which format our binary is */
 719                 if ((N_MAGIC(loc->interp_ex) != OMAGIC) &&
 720                     (N_MAGIC(loc->interp_ex) != ZMAGIC) &&
 721                     (N_MAGIC(loc->interp_ex) != QMAGIC))
 722                         interpreter_type = INTERPRETER_ELF;
 723
 724                 if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 725                         interpreter_type &= ~INTERPRETER_ELF;
 726
 727                 retval = -ELIBBAD;
 728                 if (!interpreter_type)
 729                         goto out_free_dentry;
 730
 731                 /* Make sure only one type was selected */
 732                 if ((interpreter_type & INTERPRETER_ELF) &&
 733                      interpreter_type != INTERPRETER_ELF) {
 734                         // FIXME - ratelimit this before re-enabling
 735                         // printk(KERN_WARNING "ELF: Ambiguous type, using ELF\n");
 736                         interpreter_type = INTERPRETER_ELF;
 737                 }
 738                 /* Verify the interpreter has a valid arch */
 739                 if ((interpreter_type == INTERPRETER_ELF) &&
 740                     !elf_check_arch(&loc->interp_elf_ex))
 741                         goto out_free_dentry;
 742         } else {
 743                 /* Executables without an interpreter also need a personality  */
 744                 SET_PERSONALITY(loc->elf_ex, ibcs2_interpreter);
 745         }
 746
 747         /* OK, we are done with that, now set up the arg stuff,
 748            and then start this sucker up */
 749         if ((!bprm->sh_bang) && (interpreter_type == INTERPRETER_AOUT)) {
 750                 char *passed_p = passed_fileno;
 751                 sprintf(passed_fileno, "%d", elf_exec_fileno);
 752
 753                 if (elf_interpreter) {
 754                         retval = copy_strings_kernel(1, &passed_p, bprm);
 755                         if (retval)
 756                                 goto out_free_dentry;
 757                         bprm->argc++;
 758                 }
 759         }
 760
 761         /* Flush all traces of the currently running executable */
 762         retval = flush_old_exec(bprm);
 763         if (retval)
 764                 goto out_free_dentry;
 765
 766         /* Discard our unneeded old files struct */
 767         if (files) {
 768                 put_files_struct(files);
 769                 files = NULL;
 770         }
 771
 772         /* OK, This is the point of no return */
 773         current->mm->start_data = 0;
 774         current->mm->end_data = 0;
 775         current->mm->end_code = 0;
 776         current->mm->mmap = NULL;
 777         current->flags &= ~PF_FORKNOEXEC;
 778         current->mm->def_flags = def_flags;
 779
 780         /* Do this immediately, since STACK_TOP as used in setup_arg_pages
 781            may depend on the personality.  */
 782         SET_PERSONALITY(loc->elf_ex, ibcs2_interpreter);
 783         if (elf_read_implies_exec(loc->elf_ex, executable_stack))
 784                 current->personality |= READ_IMPLIES_EXEC;
 785
 786         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 787                 current->flags |= PF_RANDOMIZE;
 788         arch_pick_mmap_layout(current->mm);
 789
 790         /* Do this so that we can load the interpreter, if need be.  We will
 791            change some of these later */
 792         current->mm->free_area_cache = current->mm->mmap_base;
 793         current->mm->cached_hole_size = 0;
 794         retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
 795                                  executable_stack);
 796         if (retval < 0) {
 797                 send_sig(SIGKILL, current, 0);
 798                 goto out_free_dentry;
 799         }
 800
 801         current->mm->start_stack = bprm->p;
 802
 803         /* Now we do a little grungy work by mmaping the ELF image into
 804            the correct location in memory.  At this point, we assume that
 805            the image should be loaded at fixed address, not at a variable
 806            address. */
 807         for(i = 0, elf_ppnt = elf_phdata;
 808             i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
 809                 int elf_prot = 0, elf_flags;
 810                 unsigned long k, vaddr;
 811
 812                 if (elf_ppnt->p_type != PT_LOAD)
 813                         continue;
 814
 815                 if (unlikely (elf_brk > elf_bss)) {
 816                         unsigned long nbyte;
 817
 818                         /* There was a PT_LOAD segment with p_memsz > p_filesz
 819                            before this one. Map anonymous pages, if needed,
 820                            and clear the area.  */
 821                         retval = set_brk (elf_bss + load_bias,
 822                                           elf_brk + load_bias);
 823                         if (retval) {
 824                                 send_sig(SIGKILL, current, 0);
 825                                 goto out_free_dentry;
 826                         }
 827                         nbyte = ELF_PAGEOFFSET(elf_bss);
 828                         if (nbyte) {
 829                                 nbyte = ELF_MIN_ALIGN - nbyte;
 830                                 if (nbyte > elf_brk - elf_bss)
 831                                         nbyte = elf_brk - elf_bss;
 832                                 if (clear_user((void __user *)elf_bss +
 833                                                         load_bias, nbyte)) {
 834                                         /*
 835                                          * This bss-zeroing can fail if the ELF
 836                                          * file specifies odd protections. So
 837                                          * we don't check the return value
 838                                          */
 839                                 }
 840                         }
 841                 }
 842
 843                 if (elf_ppnt->p_flags & PF_R)
 844                         elf_prot |= PROT_READ;
 845                 if (elf_ppnt->p_flags & PF_W)
 846                         elf_prot |= PROT_WRITE;
 847                 if (elf_ppnt->p_flags & PF_X)
 848                         elf_prot |= PROT_EXEC;
 849
 850                 elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
 851
 852                 vaddr = elf_ppnt->p_vaddr;
 853                 if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
 854                         elf_flags |= MAP_FIXED;
 855                 } else if (loc->elf_ex.e_type == ET_DYN) {
 856                         /* Try and get dynamic programs out of the way of the
 857                          * default mmap base, as well as whatever program they
 858                          * might try to exec.  This is because the brk will
 859                          * follow the loader, and is not movable.  */
 860                         load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
 861                 }
 862
 863                 error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
 864                                 elf_prot, elf_flags);
 865                 if (BAD_ADDR(error)) {
 866                         send_sig(SIGKILL, current, 0);
 867                         goto out_free_dentry;
 868                 }
 869
 870                 if (!load_addr_set) {
 871                         load_addr_set = 1;
 872                         load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
 873                         if (loc->elf_ex.e_type == ET_DYN) {
 874                                 load_bias += error -
 875                                              ELF_PAGESTART(load_bias + vaddr);
 876                                 load_addr += load_bias;
 877                                 reloc_func_desc = load_bias;
 878                         }
 879                 }
 880                 k = elf_ppnt->p_vaddr;
 881                 if (k < start_code)
 882                         start_code = k;
 883                 if (start_data < k)
 884                         start_data = k;
 885
 886                 /*
 887                  * Check to see if the section's size will overflow the
 888                  * allowed task size. Note that p_filesz must always be
 889                  * <= p_memsz so it is only necessary to check p_memsz.
 890                  */
 891                 if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
 892                     elf_ppnt->p_memsz > TASK_SIZE ||
 893                     TASK_SIZE - elf_ppnt->p_memsz < k) {
 894                         /* set_brk can never work. Avoid overflows. */
 895                         send_sig(SIGKILL, current, 0);
 896                         goto out_free_dentry;
 897                 }
 898
 899                 k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
 900
 901                 if (k > elf_bss)
 902                         elf_bss = k;
 903                 if ((elf_ppnt->p_flags & PF_X) && end_code < k)
 904                         end_code = k;
 905                 if (end_data < k)
 906                         end_data = k;
 907                 k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
 908                 if (k > elf_brk)
 909                         elf_brk = k;
 910         }
 911
 912         loc->elf_ex.e_entry += load_bias;
 913         elf_bss += load_bias;
 914         elf_brk += load_bias;
 915         start_code += load_bias;
 916         end_code += load_bias;
 917         start_data += load_bias;
 918         end_data += load_bias;
 919
 920         /* Calling set_brk effectively mmaps the pages that we need
 921          * for the bss and break sections.  We must do this before
 922          * mapping in the interpreter, to make sure it doesn't wind
 923          * up getting placed where the bss needs to go.
 924          */
 925         retval = set_brk(elf_bss, elf_brk);
 926         if (retval) {
 927                 send_sig(SIGKILL, current, 0);
 928                 goto out_free_dentry;
 929         }
 930         if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
 931                 send_sig(SIGSEGV, current, 0);
 932                 retval = -EFAULT; /* Nobody gets to see this, but.. */
 933                 goto out_free_dentry;
 934         }
 935
 936         if (elf_interpreter) {
 937                 if (interpreter_type == INTERPRETER_AOUT)
 938                         elf_entry = load_aout_interp(&loc->interp_ex,
 939                                                      interpreter);
 940                 else
 941                         elf_entry = load_elf_interp(&loc->interp_elf_ex,
 942                                                     interpreter,
 943                                                     &interp_load_addr);
 944                 if (BAD_ADDR(elf_entry)) {
 945                         force_sig(SIGSEGV, current);
 946                         retval = IS_ERR((void *)elf_entry) ?
 947                                         (int)elf_entry : -EINVAL;
 948                         goto out_free_dentry;
 949                 }
 950                 reloc_func_desc = interp_load_addr;
 951
 952                 allow_write_access(interpreter);
 953                 fput(interpreter);
 954                 kfree(elf_interpreter);
 955         } else {
 956                 elf_entry = loc->elf_ex.e_entry;
 957                 if (BAD_ADDR(elf_entry)) {
 958                         force_sig(SIGSEGV, current);
 959                         retval = -EINVAL;
 960                         goto out_free_dentry;
 961                 }
 962         }
 963
 964         kfree(elf_phdata);
 965
 966         if (interpreter_type != INTERPRETER_AOUT)
 967                 sys_close(elf_exec_fileno);
 968
 969         set_binfmt(&elf_format);
 970
 971 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 972         retval = arch_setup_additional_pages(bprm, executable_stack);
 973         if (retval < 0) {
 974                 send_sig(SIGKILL, current, 0);
 975                 goto out;
 976         }
 977 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 978
 979         compute_creds(bprm);
 980         current->flags &= ~PF_FORKNOEXEC;
 981         create_elf_tables(bprm, &loc->elf_ex,
 982                           (interpreter_type == INTERPRETER_AOUT),
 983                           load_addr, interp_load_addr);
 984         /* N.B. passed_fileno might not be initialized? */
 985         if (interpreter_type == INTERPRETER_AOUT)
 986                 current->mm->arg_start += strlen(passed_fileno) + 1;
 987         current->mm->end_code = end_code;
 988         current->mm->start_code = start_code;
 989         current->mm->start_data = start_data;
 990         current->mm->end_data = end_data;
 991         current->mm->start_stack = bprm->p;
 992
 993         if (current->personality & MMAP_PAGE_ZERO) {
 994                 /* Why this, you ask???  Well SVr4 maps page 0 as read-only,
 995                    and some applications "depend" upon this behavior.
 996                    Since we do not have the power to recompile these, we
 997                    emulate the SVr4 behavior. Sigh. */
 998                 down_write(&current->mm->mmap_sem);
 999                 error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
1000                                 MAP_FIXED | MAP_PRIVATE, 0);
1001                 up_write(&current->mm->mmap_sem);
1002         }
1003
1004 #ifdef ELF_PLAT_INIT
1005         /*
1006          * The ABI may specify that certain registers be set up in special
1007          * ways (on i386 %edx is the address of a DT_FINI function, for
1008          * example.  In addition, it may also specify (eg, PowerPC64 ELF)
1009          * that the e_entry field is the address of the function descriptor
1010          * for the startup routine, rather than the address of the startup
1011          * routine itself.  This macro performs whatever initialization to
1012          * the regs structure is required as well as any relocations to the
1013          * function descriptor entries when executing dynamically links apps.
1014          */
1015         ELF_PLAT_INIT(regs, reloc_func_desc);
1016 #endif
1017
1018         start_thread(regs, elf_entry, bprm->p);
1019         if (unlikely(current->ptrace & PT_PTRACED)) {
1020                 if (current->ptrace & PT_TRACE_EXEC)
1021                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
1022                 else
1023                         send_sig(SIGTRAP, current, 0);
1024         }
1025         retval = 0;
1026 out:
1027         kfree(loc);
1028 out_ret:
1029         return retval;
1030
1031         /* error cleanup */
1032 out_free_dentry:
1033         allow_write_access(interpreter);
1034         if (interpreter)
1035                 fput(interpreter);
1036 out_free_interp:
1037         kfree(elf_interpreter);
1038 out_free_file:
1039         sys_close(elf_exec_fileno);
1040 out_free_fh:
1041         if (files) {
1042                 put_files_struct(current->files);
1043                 current->files = files;
1044         }
1045 out_free_ph:
1046         kfree(elf_phdata);
1047         goto out;
1048 }
1049
1050 /* This is really simpleminded and specialized - we are loading an
1051    a.out library that is given an ELF header. */
1052 static int load_elf_library(struct file *file)
1053 {
1054         struct elf_phdr *elf_phdata;
1055         struct elf_phdr *eppnt;
1056         unsigned long elf_bss, bss, len;
1057         int retval, error, i, j;
1058         struct elfhdr elf_ex;
1059
1060         error = -ENOEXEC;
1061         retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
1062         if (retval != sizeof(elf_ex))
1063                 goto out;
1064
1065         if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1066                 goto out;
1067
1068         /* First of all, some simple consistency checks */
1069         if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1070             !elf_check_arch(&elf_ex) || !file->f_op || !file->f_op->mmap)
1071                 goto out;
1072
1073         /* Now read in all of the header information */
1074
1075         j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1076         /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1077
1078         error = -ENOMEM;
1079         elf_phdata = kmalloc(j, GFP_KERNEL);
1080         if (!elf_phdata)
1081                 goto out;
1082
1083         eppnt = elf_phdata;
1084         error = -ENOEXEC;
1085         retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
1086         if (retval != j)
1087                 goto out_free_ph;
1088
1089         for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1090                 if ((eppnt + i)->p_type == PT_LOAD)
1091                         j++;
1092         if (j != 1)
1093                 goto out_free_ph;
1094
1095         while (eppnt->p_type != PT_LOAD)
1096                 eppnt++;
1097
1098         /* Now use mmap to map the library into memory. */
1099         down_write(&current->mm->mmap_sem);
1100         error = do_mmap(file,
1101                         ELF_PAGESTART(eppnt->p_vaddr),
1102                         (eppnt->p_filesz +
1103                          ELF_PAGEOFFSET(eppnt->p_vaddr)),
1104                         PROT_READ | PROT_WRITE | PROT_EXEC,
1105                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
1106                         (eppnt->p_offset -
1107                          ELF_PAGEOFFSET(eppnt->p_vaddr)));
1108         up_write(&current->mm->mmap_sem);
1109         if (error != ELF_PAGESTART(eppnt->p_vaddr))
1110                 goto out_free_ph;
1111
1112         elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
1113         if (padzero(elf_bss)) {
1114                 error = -EFAULT;
1115                 goto out_free_ph;
1116         }
1117
1118         len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
1119                             ELF_MIN_ALIGN - 1);
1120         bss = eppnt->p_memsz + eppnt->p_vaddr;
1121         if (bss > len) {
1122                 down_write(&current->mm->mmap_sem);
1123                 do_brk(len, bss - len);
1124                 up_write(&current->mm->mmap_sem);
1125         }
1126         error = 0;
1127
1128 out_free_ph:
1129         kfree(elf_phdata);
1130 out:
1131         return error;
1132 }
1133
1134 /*
1135  * Note that some platforms still use traditional core dumps and not
1136  * the ELF core dump.  Each platform can select it as appropriate.
1137  */
1138 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
1139
1140 /*
1141  * ELF core dumper
1142  *
1143  * Modelled on fs/exec.c:aout_core_dump()
1144  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1145  */
1146 /*
1147  * These are the only things you should do on a core-file: use only these
1148  * functions to write out all the necessary info.
1149  */
1150 static int dump_write(struct file *file, const void *addr, int nr)
1151 {
1152         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
1153 }
1154
1155 static int dump_seek(struct file *file, loff_t off)
1156 {
1157         if (file->f_op->llseek) {
1158                 if (file->f_op->llseek(file, off, 0) != off)
1159                         return 0;
1160         } else
1161                 file->f_pos = off;
1162         return 1;
1163 }
1164
1165 /*
1166  * Decide whether a segment is worth dumping; default is yes to be
1167  * sure (missing info is worse than too much; etc).
1168  * Personally I'd include everything, and use the coredump limit...
1169  *
1170  * I think we should skip something. But I am not sure how. H.J.
1171  */
1172 static int maydump(struct vm_area_struct *vma)
1173 {
1174         /* Do not dump I/O mapped devices or special mappings */
1175         if (vma->vm_flags & (VM_IO | VM_RESERVED))
1176                 return 0;
1177
1178         /* Dump shared memory only if mapped from an anonymous file. */
1179         if (vma->vm_flags & VM_SHARED)
1180                 return vma->vm_file->f_dentry->d_inode->i_nlink == 0;
1181
1182         /* If it hasn't been written to, don't write it out */
1183         if (!vma->anon_vma)
1184                 return 0;
1185
1186         return 1;
1187 }
1188
1189 /* An ELF note in memory */
1190 struct memelfnote
1191 {
1192         const char *name;
1193         int type;
1194         unsigned int datasz;
1195         void *data;
1196 };
1197
1198 static int notesize(struct memelfnote *en)
1199 {
1200         int sz;
1201
1202         sz = sizeof(struct elf_note);
1203         sz += roundup(strlen(en->name) + 1, 4);
1204         sz += roundup(en->datasz, 4);
1205
1206         return sz;
1207 }
1208
1209 #define DUMP_WRITE(addr, nr)    \
1210         do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
1211 #define DUMP_SEEK(off)  \
1212         do { if (!dump_seek(file, (off))) return 0; } while(0)
1213
1214 static int writenote(struct memelfnote *men, struct file *file)
1215 {
1216         struct elf_note en;
1217
1218         en.n_namesz = strlen(men->name) + 1;
1219         en.n_descsz = men->datasz;
1220         en.n_type = men->type;
1221
1222         DUMP_WRITE(&en, sizeof(en));
1223         DUMP_WRITE(men->name, en.n_namesz);
1224         /* XXX - cast from long long to long to avoid need for libgcc.a */
1225         DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));      /* XXX */
1226         DUMP_WRITE(men->data, men->datasz);
1227         DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));      /* XXX */
1228
1229         return 1;
1230 }
1231 #undef DUMP_WRITE
1232 #undef DUMP_SEEK
1233
1234 #define DUMP_WRITE(addr, nr)    \
1235         if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
1236                 goto end_coredump;
1237 #define DUMP_SEEK(off)  \
1238         if (!dump_seek(file, (off))) \
1239                 goto end_coredump;
1240
1241 static void fill_elf_header(struct elfhdr *elf, int segs)
1242 {
1243         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1244         elf->e_ident[EI_CLASS] = ELF_CLASS;
1245         elf->e_ident[EI_DATA] = ELF_DATA;
1246         elf->e_ident[EI_VERSION] = EV_CURRENT;
1247         elf->e_ident[EI_OSABI] = ELF_OSABI;
1248         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1249
1250         elf->e_type = ET_CORE;
1251         elf->e_machine = ELF_ARCH;
1252         elf->e_version = EV_CURRENT;
1253         elf->e_entry = 0;
1254         elf->e_phoff = sizeof(struct elfhdr);
1255         elf->e_shoff = 0;
1256         elf->e_flags = ELF_CORE_EFLAGS;
1257         elf->e_ehsize = sizeof(struct elfhdr);
1258         elf->e_phentsize = sizeof(struct elf_phdr);
1259         elf->e_phnum = segs;
1260         elf->e_shentsize = 0;
1261         elf->e_shnum = 0;
1262         elf->e_shstrndx = 0;
1263         return;
1264 }
1265
1266 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1267 {
1268         phdr->p_type = PT_NOTE;
1269         phdr->p_offset = offset;
1270         phdr->p_vaddr = 0;
1271         phdr->p_paddr = 0;
1272         phdr->p_filesz = sz;
1273         phdr->p_memsz = 0;
1274         phdr->p_flags = 0;
1275         phdr->p_align = 0;
1276         return;
1277 }
1278
1279 static void fill_note(struct memelfnote *note, const char *name, int type,
1280                 unsigned int sz, void *data)
1281 {
1282         note->name = name;
1283         note->type = type;
1284         note->datasz = sz;
1285         note->data = data;
1286         return;
1287 }
1288
1289 /*
1290  * fill up all the fields in prstatus from the given task struct, except
1291  * registers which need to be filled up separately.
1292  */
1293 static void fill_prstatus(struct elf_prstatus *prstatus,
1294                 struct task_struct *p, long signr)
1295 {
1296         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1297         prstatus->pr_sigpend = p->pending.signal.sig[0];
1298         prstatus->pr_sighold = p->blocked.sig[0];
1299         prstatus->pr_pid = p->pid;
1300         prstatus->pr_ppid = p->parent->pid;
1301         prstatus->pr_pgrp = process_group(p);
1302         prstatus->pr_sid = p->signal->session;
1303         if (thread_group_leader(p)) {
1304                 /*
1305                  * This is the record for the group leader.  Add in the
1306                  * cumulative times of previous dead threads.  This total
1307                  * won't include the time of each live thread whose state
1308                  * is included in the core dump.  The final total reported
1309                  * to our parent process when it calls wait4 will include
1310                  * those sums as well as the little bit more time it takes
1311                  * this and each other thread to finish dying after the
1312                  * core dump synchronization phase.
1313                  */
1314                 cputime_to_timeval(cputime_add(p->utime, p->signal->utime),
1315                                    &prstatus->pr_utime);
1316                 cputime_to_timeval(cputime_add(p->stime, p->signal->stime),
1317                                    &prstatus->pr_stime);
1318         } else {
1319                 cputime_to_timeval(p->utime, &prstatus->pr_utime);
1320                 cputime_to_timeval(p->stime, &prstatus->pr_stime);
1321         }
1322         cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1323         cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1324 }
1325
1326 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1327                        struct mm_struct *mm)
1328 {
1329         unsigned int i, len;
1330
1331         /* first copy the parameters from user space */
1332         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1333
1334         len = mm->arg_end - mm->arg_start;
1335         if (len >= ELF_PRARGSZ)
1336                 len = ELF_PRARGSZ-1;
1337         if (copy_from_user(&psinfo->pr_psargs,
1338                            (const char __user *)mm->arg_start, len))
1339                 return -EFAULT;
1340         for(i = 0; i < len; i++)
1341                 if (psinfo->pr_psargs[i] == 0)
1342                         psinfo->pr_psargs[i] = ' ';
1343         psinfo->pr_psargs[len] = 0;
1344
1345         psinfo->pr_pid = p->pid;
1346         psinfo->pr_ppid = p->parent->pid;
1347         psinfo->pr_pgrp = process_group(p);
1348         psinfo->pr_sid = p->signal->session;
1349
1350         i = p->state ? ffz(~p->state) + 1 : 0;
1351         psinfo->pr_state = i;
1352         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1353         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1354         psinfo->pr_nice = task_nice(p);
1355         psinfo->pr_flag = p->flags;
1356         SET_UID(psinfo->pr_uid, p->uid);
1357         SET_GID(psinfo->pr_gid, p->gid);
1358         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1359
1360         return 0;
1361 }
1362
1363 /* Here is the structure in which status of each thread is captured. */
1364 struct elf_thread_status
1365 {
1366         struct list_head list;
1367         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1368         elf_fpregset_t fpu;             /* NT_PRFPREG */
1369         struct task_struct *thread;
1370 #ifdef ELF_CORE_COPY_XFPREGS
1371         elf_fpxregset_t xfpu;           /* NT_PRXFPREG */
1372 #endif
1373         struct memelfnote notes[3];
1374         int num_notes;
1375 };
1376
1377 /*
1378  * In order to add the specific thread information for the elf file format,
1379  * we need to keep a linked list of every threads pr_status and then create
1380  * a single section for them in the final core file.
1381  */
1382 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1383 {
1384         int sz = 0;
1385         struct task_struct *p = t->thread;
1386         t->num_notes = 0;
1387
1388         fill_prstatus(&t->prstatus, p, signr);
1389         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1390
1391         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1392                   &(t->prstatus));
1393         t->num_notes++;
1394         sz += notesize(&t->notes[0]);
1395
1396         if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
1397                                                                 &t->fpu))) {
1398                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1399                           &(t->fpu));
1400                 t->num_notes++;
1401                 sz += notesize(&t->notes[1]);
1402         }
1403
1404 #ifdef ELF_CORE_COPY_XFPREGS
1405         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1406                 fill_note(&t->notes[2], "LINUX", NT_PRXFPREG, sizeof(t->xfpu),
1407                           &t->xfpu);
1408                 t->num_notes++;
1409                 sz += notesize(&t->notes[2]);
1410         }
1411 #endif
1412         return sz;
1413 }
1414
1415 /*
1416  * Actual dumper
1417  *
1418  * This is a two-pass process; first we find the offsets of the bits,
1419  * and then they are actually written out.  If we run out of core limit
1420  * we just truncate.
1421  */
1422 static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file)
1423 {
1424 #define NUM_NOTES       6
1425         int has_dumped = 0;
1426         mm_segment_t fs;
1427         int segs;
1428         size_t size = 0;
1429         int i;
1430         struct vm_area_struct *vma;
1431         struct elfhdr *elf = NULL;
1432         loff_t offset = 0, dataoff;
1433         unsigned long limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
1434         int numnote;
1435         struct memelfnote *notes = NULL;
1436         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
1437         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
1438         struct task_struct *g, *p;
1439         LIST_HEAD(thread_list);
1440         struct list_head *t;
1441         elf_fpregset_t *fpu = NULL;
1442 #ifdef ELF_CORE_COPY_XFPREGS
1443         elf_fpxregset_t *xfpu = NULL;
1444 #endif
1445         int thread_status_size = 0;
1446         elf_addr_t *auxv;
1447
1448         /*
1449          * We no longer stop all VM operations.
1450          *
1451          * This is because those proceses that could possibly change map_count
1452          * or the mmap / vma pages are now blocked in do_exit on current
1453          * finishing this core dump.
1454          *
1455          * Only ptrace can touch these memory addresses, but it doesn't change
1456          * the map_count or the pages allocated. So no possibility of crashing
1457          * exists while dumping the mm->vm_next areas to the core file.
1458          */
1459
1460         /* alloc memory for large data structures: too large to be on stack */
1461         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1462         if (!elf)
1463                 goto cleanup;
1464         prstatus = kmalloc(sizeof(*prstatus), GFP_KERNEL);
1465         if (!prstatus)
1466                 goto cleanup;
1467         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1468         if (!psinfo)
1469                 goto cleanup;
1470         notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
1471         if (!notes)
1472                 goto cleanup;
1473         fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1474         if (!fpu)
1475                 goto cleanup;
1476 #ifdef ELF_CORE_COPY_XFPREGS
1477         xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1478         if (!xfpu)
1479                 goto cleanup;
1480 #endif
1481
1482         if (signr) {
1483                 struct elf_thread_status *tmp;
1484                 read_lock(&tasklist_lock);
1485                 do_each_thread(g,p)
1486                         if (current->mm == p->mm && current != p) {
1487                                 tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
1488                                 if (!tmp) {
1489                                         read_unlock(&tasklist_lock);
1490                                         goto cleanup;
1491                                 }
1492                                 INIT_LIST_HEAD(&tmp->list);
1493                                 tmp->thread = p;
1494                                 list_add(&tmp->list, &thread_list);
1495                         }
1496                 while_each_thread(g,p);
1497                 read_unlock(&tasklist_lock);
1498                 list_for_each(t, &thread_list) {
1499                         struct elf_thread_status *tmp;
1500                         int sz;
1501
1502                         tmp = list_entry(t, struct elf_thread_status, list);
1503                         sz = elf_dump_thread_status(signr, tmp);
1504                         thread_status_size += sz;
1505                 }
1506         }
1507         /* now collect the dump for the current */
1508         memset(prstatus, 0, sizeof(*prstatus));
1509         fill_prstatus(prstatus, current, signr);
1510         elf_core_copy_regs(&prstatus->pr_reg, regs);
1511
1512         segs = current->mm->map_count;
1513 #ifdef ELF_CORE_EXTRA_PHDRS
1514         segs += ELF_CORE_EXTRA_PHDRS;
1515 #endif
1516
1517         /* Set up header */
1518         fill_elf_header(elf, segs + 1); /* including notes section */
1519
1520         has_dumped = 1;
1521         current->flags |= PF_DUMPCORE;
1522
1523         /*
1524          * Set up the notes in similar form to SVR4 core dumps made
1525          * with info from their /proc.
1526          */
1527
1528         fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1529         fill_psinfo(psinfo, current->group_leader, current->mm);
1530         fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1531
1532         numnote = 2;
1533
1534         auxv = (elf_addr_t *)current->mm->saved_auxv;
1535
1536         i = 0;
1537         do
1538                 i += 2;
1539         while (auxv[i - 2] != AT_NULL);
1540         fill_note(&notes[numnote++], "CORE", NT_AUXV,
1541                   i * sizeof(elf_addr_t), auxv);
1542
1543         /* Try to dump the FPU. */
1544         if ((prstatus->pr_fpvalid =
1545              elf_core_copy_task_fpregs(current, regs, fpu)))
1546                 fill_note(notes + numnote++,
1547                           "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1548 #ifdef ELF_CORE_COPY_XFPREGS
1549         if (elf_core_copy_task_xfpregs(current, xfpu))
1550                 fill_note(notes + numnote++,
1551                           "LINUX", NT_PRXFPREG, sizeof(*xfpu), xfpu);
1552 #endif
1553
1554         fs = get_fs();
1555         set_fs(KERNEL_DS);
1556
1557         DUMP_WRITE(elf, sizeof(*elf));
1558         offset += sizeof(*elf);                         /* Elf header */
1559         offset += (segs+1) * sizeof(struct elf_phdr);   /* Program headers */
1560
1561         /* Write notes phdr entry */
1562         {
1563                 struct elf_phdr phdr;
1564                 int sz = 0;
1565
1566                 for (i = 0; i < numnote; i++)
1567                         sz += notesize(notes + i);
1568
1569                 sz += thread_status_size;
1570
1571                 fill_elf_note_phdr(&phdr, sz, offset);
1572                 offset += sz;
1573                 DUMP_WRITE(&phdr, sizeof(phdr));
1574         }
1575
1576         /* Page-align dumped data */
1577         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1578
1579         /* Write program headers for segments dump */
1580         for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
1581                 struct elf_phdr phdr;
1582                 size_t sz;
1583
1584                 sz = vma->vm_end - vma->vm_start;
1585
1586                 phdr.p_type = PT_LOAD;
1587                 phdr.p_offset = offset;
1588                 phdr.p_vaddr = vma->vm_start;
1589                 phdr.p_paddr = 0;
1590                 phdr.p_filesz = maydump(vma) ? sz : 0;
1591                 phdr.p_memsz = sz;
1592                 offset += phdr.p_filesz;
1593                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1594                 if (vma->vm_flags & VM_WRITE)
1595                         phdr.p_flags |= PF_W;
1596                 if (vma->vm_flags & VM_EXEC)
1597                         phdr.p_flags |= PF_X;
1598                 phdr.p_align = ELF_EXEC_PAGESIZE;
1599
1600                 DUMP_WRITE(&phdr, sizeof(phdr));
1601         }
1602
1603 #ifdef ELF_CORE_WRITE_EXTRA_PHDRS
1604         ELF_CORE_WRITE_EXTRA_PHDRS;
1605 #endif
1606
1607         /* write out the notes section */
1608         for (i = 0; i < numnote; i++)
1609                 if (!writenote(notes + i, file))
1610                         goto end_coredump;
1611
1612         /* write out the thread status notes section */
1613         list_for_each(t, &thread_list) {
1614                 struct elf_thread_status *tmp =
1615                                 list_entry(t, struct elf_thread_status, list);
1616
1617                 for (i = 0; i < tmp->num_notes; i++)
1618                         if (!writenote(&tmp->notes[i], file))
1619                                 goto end_coredump;
1620         }
1621
1622         DUMP_SEEK(dataoff);
1623
1624         for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
1625                 unsigned long addr;
1626
1627                 if (!maydump(vma))
1628                         continue;
1629
1630                 for (addr = vma->vm_start;
1631                      addr < vma->vm_end;
1632                      addr += PAGE_SIZE) {
1633                         struct page *page;
1634                         struct vm_area_struct *vma;
1635
1636                         if (get_user_pages(current, current->mm, addr, 1, 0, 1,
1637                                                 &page, &vma) <= 0) {
1638                                 DUMP_SEEK(file->f_pos + PAGE_SIZE);
1639                         } else {
1640                                 if (page == ZERO_PAGE(addr)) {
1641                                         DUMP_SEEK(file->f_pos + PAGE_SIZE);
1642                                 } else {
1643                                         void *kaddr;
1644                                         flush_cache_page(vma, addr,
1645                                                          page_to_pfn(page));
1646                                         kaddr = kmap(page);
1647                                         if ((size += PAGE_SIZE) > limit ||
1648                                             !dump_write(file, kaddr,
1649                                             PAGE_SIZE)) {
1650                                                 kunmap(page);
1651                                                 page_cache_release(page);
1652                                                 goto end_coredump;
1653                                         }
1654                                         kunmap(page);
1655                                 }
1656                                 page_cache_release(page);
1657                         }
1658                 }
1659         }
1660
1661 #ifdef ELF_CORE_WRITE_EXTRA_DATA
1662         ELF_CORE_WRITE_EXTRA_DATA;
1663 #endif
1664
1665         if (file->f_pos != offset) {
1666                 /* Sanity check */
1667                 printk(KERN_WARNING
1668                        "elf_core_dump: file->f_pos (%Ld) != offset (%Ld)\n",
1669                        file->f_pos, offset);
1670         }
1671
1672 end_coredump:
1673         set_fs(fs);
1674
1675 cleanup:
1676         while (!list_empty(&thread_list)) {
1677                 struct list_head *tmp = thread_list.next;
1678                 list_del(tmp);
1679                 kfree(list_entry(tmp, struct elf_thread_status, list));
1680         }
1681
1682         kfree(elf);
1683         kfree(prstatus);
1684         kfree(psinfo);
1685         kfree(notes);
1686         kfree(fpu);
1687 #ifdef ELF_CORE_COPY_XFPREGS
1688         kfree(xfpu);
1689 #endif
1690         return has_dumped;
1691 #undef NUM_NOTES
1692 }
1693
1694 #endif          /* USE_ELF_CORE_DUMP */
1695
1696 static int __init init_elf_binfmt(void)
1697 {
1698         return register_binfmt(&elf_format);
1699 }
1700
1701 static void __exit exit_elf_binfmt(void)
1702 {
1703         /* Remove the COFF and ELF loaders. */
1704         unregister_binfmt(&elf_format);
1705 }
1706
1707 core_initcall(init_elf_binfmt);
1708 module_exit(exit_elf_binfmt);
1709 MODULE_LICENSE("GPL");