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   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/errno.h>
  20 #include <linux/signal.h>
  21 #include <linux/binfmts.h>
  22 #include <linux/string.h>
  23 #include <linux/file.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/slab.h>
  27 #include <linux/shm.h>
  28 #include <linux/personality.h>
  29 #include <linux/elfcore.h>
  30 #include <linux/init.h>
  31 #include <linux/highuid.h>
  32 #include <linux/smp.h>
  33 #include <linux/compiler.h>
  34 #include <linux/highmem.h>
  35 #include <linux/pagemap.h>
  36 #include <linux/security.h>
  37 #include <linux/syscalls.h>
  38 #include <linux/random.h>
  39 #include <linux/elf.h>
  40 #include <linux/utsname.h>
  41 #include <asm/uaccess.h>
  42 #include <asm/param.h>
  43 #include <asm/page.h>
  44
  45 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  46 static int load_elf_library(struct file *);
  47 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
  48                                 int, int, unsigned long);
  49
  50 /*
  51  * If we don't support core dumping, then supply a NULL so we
  52  * don't even try.
  53  */
  54 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
  55 static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
  56 #else
  57 #define elf_core_dump   NULL
  58 #endif
  59
  60 #if ELF_EXEC_PAGESIZE > PAGE_SIZE
  61 #define ELF_MIN_ALIGN   ELF_EXEC_PAGESIZE
  62 #else
  63 #define ELF_MIN_ALIGN   PAGE_SIZE
  64 #endif
  65
  66 #ifndef ELF_CORE_EFLAGS
  67 #define ELF_CORE_EFLAGS 0
  68 #endif
  69
  70 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
  71 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
  72 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
  73
  74 static struct linux_binfmt elf_format = {
  75                 .module         = THIS_MODULE,
  76                 .load_binary    = load_elf_binary,
  77                 .load_shlib     = load_elf_library,
  78                 .core_dump      = elf_core_dump,
  79                 .min_coredump   = ELF_EXEC_PAGESIZE,
  80                 .hasvdso        = 1
  81 };
  82
  83 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
  84
  85 static int set_brk(unsigned long start, unsigned long end)
  86 {
  87         start = ELF_PAGEALIGN(start);
  88         end = ELF_PAGEALIGN(end);
  89         if (end > start) {
  90                 unsigned long addr;
  91                 down_write(&current->mm->mmap_sem);
  92                 addr = do_brk(start, end - start);
  93                 up_write(&current->mm->mmap_sem);
  94                 if (BAD_ADDR(addr))
  95                         return addr;
  96         }
  97         current->mm->start_brk = current->mm->brk = end;
  98         return 0;
  99 }
 100
 101 /* We need to explicitly zero any fractional pages
 102    after the data section (i.e. bss).  This would
 103    contain the junk from the file that should not
 104    be in memory
 105  */
 106 static int padzero(unsigned long elf_bss)
 107 {
 108         unsigned long nbyte;
 109
 110         nbyte = ELF_PAGEOFFSET(elf_bss);
 111         if (nbyte) {
 112                 nbyte = ELF_MIN_ALIGN - nbyte;
 113                 if (clear_user((void __user *) elf_bss, nbyte))
 114                         return -EFAULT;
 115         }
 116         return 0;
 117 }
 118
 119 /* Let's use some macros to make this stack manipulation a little clearer */
 120 #ifdef CONFIG_STACK_GROWSUP
 121 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
 122 #define STACK_ROUND(sp, items) \
 123         ((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
 124 #define STACK_ALLOC(sp, len) ({ \
 125         elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
 126         old_sp; })
 127 #else
 128 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
 129 #define STACK_ROUND(sp, items) \
 130         (((unsigned long) (sp - items)) &~ 15UL)
 131 #define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
 132 #endif
 133
 134 #ifndef ELF_BASE_PLATFORM
 135 /*
 136  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 137  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 138  * will be copied to the user stack in the same manner as AT_PLATFORM.
 139  */
 140 #define ELF_BASE_PLATFORM NULL
 141 #endif
 142
 143 static int
 144 create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
 145                 unsigned long load_addr, unsigned long interp_load_addr)
 146 {
 147         unsigned long p = bprm->p;
 148         int argc = bprm->argc;
 149         int envc = bprm->envc;
 150         elf_addr_t __user *argv;
 151         elf_addr_t __user *envp;
 152         elf_addr_t __user *sp;
 153         elf_addr_t __user *u_platform;
 154         elf_addr_t __user *u_base_platform;
 155         elf_addr_t __user *u_rand_bytes;
 156         const char *k_platform = ELF_PLATFORM;
 157         const char *k_base_platform = ELF_BASE_PLATFORM;
 158         unsigned char k_rand_bytes[16];
 159         int items;
 160         elf_addr_t *elf_info;
 161         int ei_index = 0;
 162         const struct cred *cred = current_cred();
 163         struct vm_area_struct *vma;
 164
 165         /*
 166          * In some cases (e.g. Hyper-Threading), we want to avoid L1
 167          * evictions by the processes running on the same package. One
 168          * thing we can do is to shuffle the initial stack for them.
 169          */
 170
 171         p = arch_align_stack(p);
 172
 173         /*
 174          * If this architecture has a platform capability string, copy it
 175          * to userspace.  In some cases (Sparc), this info is impossible
 176          * for userspace to get any other way, in others (i386) it is
 177          * merely difficult.
 178          */
 179         u_platform = NULL;
 180         if (k_platform) {
 181                 size_t len = strlen(k_platform) + 1;
 182
 183                 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 184                 if (__copy_to_user(u_platform, k_platform, len))
 185                         return -EFAULT;
 186         }
 187
 188         /*
 189          * If this architecture has a "base" platform capability
 190          * string, copy it to userspace.
 191          */
 192         u_base_platform = NULL;
 193         if (k_base_platform) {
 194                 size_t len = strlen(k_base_platform) + 1;
 195
 196                 u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 197                 if (__copy_to_user(u_base_platform, k_base_platform, len))
 198                         return -EFAULT;
 199         }
 200
 201         /*
 202          * Generate 16 random bytes for userspace PRNG seeding.
 203          */
 204         get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
 205         u_rand_bytes = (elf_addr_t __user *)
 206                        STACK_ALLOC(p, sizeof(k_rand_bytes));
 207         if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
 208                 return -EFAULT;
 209
 210         /* Create the ELF interpreter info */
 211         elf_info = (elf_addr_t *)current->mm->saved_auxv;
 212         /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
 213 #define NEW_AUX_ENT(id, val) \
 214         do { \
 215                 elf_info[ei_index++] = id; \
 216                 elf_info[ei_index++] = val; \
 217         } while (0)
 218
 219 #ifdef ARCH_DLINFO
 220         /*
 221          * ARCH_DLINFO must come first so PPC can do its special alignment of
 222          * AUXV.
 223          * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
 224          * ARCH_DLINFO changes
 225          */
 226         ARCH_DLINFO;
 227 #endif
 228         NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
 229         NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
 230         NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
 231         NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
 232         NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
 233         NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
 234         NEW_AUX_ENT(AT_BASE, interp_load_addr);
 235         NEW_AUX_ENT(AT_FLAGS, 0);
 236         NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
 237         NEW_AUX_ENT(AT_UID, cred->uid);
 238         NEW_AUX_ENT(AT_EUID, cred->euid);
 239         NEW_AUX_ENT(AT_GID, cred->gid);
 240         NEW_AUX_ENT(AT_EGID, cred->egid);
 241         NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
 242         NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
 243         NEW_AUX_ENT(AT_EXECFN, bprm->exec);
 244         if (k_platform) {
 245                 NEW_AUX_ENT(AT_PLATFORM,
 246                             (elf_addr_t)(unsigned long)u_platform);
 247         }
 248         if (k_base_platform) {
 249                 NEW_AUX_ENT(AT_BASE_PLATFORM,
 250                             (elf_addr_t)(unsigned long)u_base_platform);
 251         }
 252         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
 253                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
 254         }
 255 #undef NEW_AUX_ENT
 256         /* AT_NULL is zero; clear the rest too */
 257         memset(&elf_info[ei_index], 0,
 258                sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
 259
 260         /* And advance past the AT_NULL entry.  */
 261         ei_index += 2;
 262
 263         sp = STACK_ADD(p, ei_index);
 264
 265         items = (argc + 1) + (envc + 1) + 1;
 266         bprm->p = STACK_ROUND(sp, items);
 267
 268         /* Point sp at the lowest address on the stack */
 269 #ifdef CONFIG_STACK_GROWSUP
 270         sp = (elf_addr_t __user *)bprm->p - items - ei_index;
 271         bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
 272 #else
 273         sp = (elf_addr_t __user *)bprm->p;
 274 #endif
 275
 276
 277         /*
 278          * Grow the stack manually; some architectures have a limit on how
 279          * far ahead a user-space access may be in order to grow the stack.
 280          */
 281         vma = find_extend_vma(current->mm, bprm->p);
 282         if (!vma)
 283                 return -EFAULT;
 284
 285         /* Now, let's put argc (and argv, envp if appropriate) on the stack */
 286         if (__put_user(argc, sp++))
 287                 return -EFAULT;
 288         argv = sp;
 289         envp = argv + argc + 1;
 290
 291         /* Populate argv and envp */
 292         p = current->mm->arg_end = current->mm->arg_start;
 293         while (argc-- > 0) {
 294                 size_t len;
 295                 if (__put_user((elf_addr_t)p, argv++))
 296                         return -EFAULT;
 297                 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
 298                 if (!len || len > MAX_ARG_STRLEN)
 299                         return -EINVAL;
 300                 p += len;
 301         }
 302         if (__put_user(0, argv))
 303                 return -EFAULT;
 304         current->mm->arg_end = current->mm->env_start = p;
 305         while (envc-- > 0) {
 306                 size_t len;
 307                 if (__put_user((elf_addr_t)p, envp++))
 308                         return -EFAULT;
 309                 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
 310                 if (!len || len > MAX_ARG_STRLEN)
 311                         return -EINVAL;
 312                 p += len;
 313         }
 314         if (__put_user(0, envp))
 315                 return -EFAULT;
 316         current->mm->env_end = p;
 317
 318         /* Put the elf_info on the stack in the right place.  */
 319         sp = (elf_addr_t __user *)envp + 1;
 320         if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
 321                 return -EFAULT;
 322         return 0;
 323 }
 324
 325 #ifndef elf_map
 326
 327 static unsigned long elf_map(struct file *filep, unsigned long addr,
 328                 struct elf_phdr *eppnt, int prot, int type,
 329                 unsigned long total_size)
 330 {
 331         unsigned long map_addr;
 332         unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
 333         unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
 334         addr = ELF_PAGESTART(addr);
 335         size = ELF_PAGEALIGN(size);
 336
 337         /* mmap() will return -EINVAL if given a zero size, but a
 338          * segment with zero filesize is perfectly valid */
 339         if (!size)
 340                 return addr;
 341
 342         down_write(&current->mm->mmap_sem);
 343         /*
 344         * total_size is the size of the ELF (interpreter) image.
 345         * The _first_ mmap needs to know the full size, otherwise
 346         * randomization might put this image into an overlapping
 347         * position with the ELF binary image. (since size < total_size)
 348         * So we first map the 'big' image - and unmap the remainder at
 349         * the end. (which unmap is needed for ELF images with holes.)
 350         */
 351         if (total_size) {
 352                 total_size = ELF_PAGEALIGN(total_size);
 353                 map_addr = do_mmap(filep, addr, total_size, prot, type, off);
 354                 if (!BAD_ADDR(map_addr))
 355                         do_munmap(current->mm, map_addr+size, total_size-size);
 356         } else
 357                 map_addr = do_mmap(filep, addr, size, prot, type, off);
 358
 359         up_write(&current->mm->mmap_sem);
 360         return(map_addr);
 361 }
 362
 363 #endif /* !elf_map */
 364
 365 static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
 366 {
 367         int i, first_idx = -1, last_idx = -1;
 368
 369         for (i = 0; i < nr; i++) {
 370                 if (cmds[i].p_type == PT_LOAD) {
 371                         last_idx = i;
 372                         if (first_idx == -1)
 373                                 first_idx = i;
 374                 }
 375         }
 376         if (first_idx == -1)
 377                 return 0;
 378
 379         return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
 380                                 ELF_PAGESTART(cmds[first_idx].p_vaddr);
 381 }
 382
 383
 384 /* This is much more generalized than the library routine read function,
 385    so we keep this separate.  Technically the library read function
 386    is only provided so that we can read a.out libraries that have
 387    an ELF header */
 388
 389 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 390                 struct file *interpreter, unsigned long *interp_map_addr,
 391                 unsigned long no_base)
 392 {
 393         struct elf_phdr *elf_phdata;
 394         struct elf_phdr *eppnt;
 395         unsigned long load_addr = 0;
 396         int load_addr_set = 0;
 397         unsigned long last_bss = 0, elf_bss = 0;
 398         unsigned long error = ~0UL;
 399         unsigned long total_size;
 400         int retval, i, size;
 401
 402         /* First of all, some simple consistency checks */
 403         if (interp_elf_ex->e_type != ET_EXEC &&
 404             interp_elf_ex->e_type != ET_DYN)
 405                 goto out;
 406         if (!elf_check_arch(interp_elf_ex))
 407                 goto out;
 408         if (!interpreter->f_op || !interpreter->f_op->mmap)
 409                 goto out;
 410
 411         /*
 412          * If the size of this structure has changed, then punt, since
 413          * we will be doing the wrong thing.
 414          */
 415         if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
 416                 goto out;
 417         if (interp_elf_ex->e_phnum < 1 ||
 418                 interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
 419                 goto out;
 420
 421         /* Now read in all of the header information */
 422         size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
 423         if (size > ELF_MIN_ALIGN)
 424                 goto out;
 425         elf_phdata = kmalloc(size, GFP_KERNEL);
 426         if (!elf_phdata)
 427                 goto out;
 428
 429         retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
 430                              (char *)elf_phdata,size);
 431         error = -EIO;
 432         if (retval != size) {
 433                 if (retval < 0)
 434                         error = retval;
 435                 goto out_close;
 436         }
 437
 438         total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
 439         if (!total_size) {
 440                 error = -EINVAL;
 441                 goto out_close;
 442         }
 443
 444         eppnt = elf_phdata;
 445         for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
 446                 if (eppnt->p_type == PT_LOAD) {
 447                         int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
 448                         int elf_prot = 0;
 449                         unsigned long vaddr = 0;
 450                         unsigned long k, map_addr;
 451
 452                         if (eppnt->p_flags & PF_R)
 453                                 elf_prot = PROT_READ;
 454                         if (eppnt->p_flags & PF_W)
 455                                 elf_prot |= PROT_WRITE;
 456                         if (eppnt->p_flags & PF_X)
 457                                 elf_prot |= PROT_EXEC;
 458                         vaddr = eppnt->p_vaddr;
 459                         if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
 460                                 elf_type |= MAP_FIXED;
 461                         else if (no_base && interp_elf_ex->e_type == ET_DYN)
 462                                 load_addr = -vaddr;
 463
 464                         map_addr = elf_map(interpreter, load_addr + vaddr,
 465                                         eppnt, elf_prot, elf_type, total_size);
 466                         total_size = 0;
 467                         if (!*interp_map_addr)
 468                                 *interp_map_addr = map_addr;
 469                         error = map_addr;
 470                         if (BAD_ADDR(map_addr))
 471                                 goto out_close;
 472
 473                         if (!load_addr_set &&
 474                             interp_elf_ex->e_type == ET_DYN) {
 475                                 load_addr = map_addr - ELF_PAGESTART(vaddr);
 476                                 load_addr_set = 1;
 477                         }
 478
 479                         /*
 480                          * Check to see if the section's size will overflow the
 481                          * allowed task size. Note that p_filesz must always be
 482                          * <= p_memsize so it's only necessary to check p_memsz.
 483                          */
 484                         k = load_addr + eppnt->p_vaddr;
 485                         if (BAD_ADDR(k) ||
 486                             eppnt->p_filesz > eppnt->p_memsz ||
 487                             eppnt->p_memsz > TASK_SIZE ||
 488                             TASK_SIZE - eppnt->p_memsz < k) {
 489                                 error = -ENOMEM;
 490                                 goto out_close;
 491                         }
 492
 493                         /*
 494                          * Find the end of the file mapping for this phdr, and
 495                          * keep track of the largest address we see for this.
 496                          */
 497                         k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
 498                         if (k > elf_bss)
 499                                 elf_bss = k;
 500
 501                         /*
 502                          * Do the same thing for the memory mapping - between
 503                          * elf_bss and last_bss is the bss section.
 504                          */
 505                         k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
 506                         if (k > last_bss)
 507                                 last_bss = k;
 508                 }
 509         }
 510
 511         /*
 512          * Now fill out the bss section.  First pad the last page up
 513          * to the page boundary, and then perform a mmap to make sure
 514          * that there are zero-mapped pages up to and including the
 515          * last bss page.
 516          */
 517         if (padzero(elf_bss)) {
 518                 error = -EFAULT;
 519                 goto out_close;
 520         }
 521
 522         /* What we have mapped so far */
 523         elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
 524
 525         /* Map the last of the bss segment */
 526         if (last_bss > elf_bss) {
 527                 down_write(&current->mm->mmap_sem);
 528                 error = do_brk(elf_bss, last_bss - elf_bss);
 529                 up_write(&current->mm->mmap_sem);
 530                 if (BAD_ADDR(error))
 531                         goto out_close;
 532         }
 533
 534         error = load_addr;
 535
 536 out_close:
 537         kfree(elf_phdata);
 538 out:
 539         return error;
 540 }
 541
 542 /*
 543  * These are the functions used to load ELF style executables and shared
 544  * libraries.  There is no binary dependent code anywhere else.
 545  */
 546
 547 #define INTERPRETER_NONE 0
 548 #define INTERPRETER_ELF 2
 549
 550 #ifndef STACK_RND_MASK
 551 #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))     /* 8MB of VA */
 552 #endif
 553
 554 static unsigned long randomize_stack_top(unsigned long stack_top)
 555 {
 556         unsigned int random_variable = 0;
 557
 558         if ((current->flags & PF_RANDOMIZE) &&
 559                 !(current->personality & ADDR_NO_RANDOMIZE)) {
 560                 random_variable = get_random_int() & STACK_RND_MASK;
 561                 random_variable <<= PAGE_SHIFT;
 562         }
 563 #ifdef CONFIG_STACK_GROWSUP
 564         return PAGE_ALIGN(stack_top) + random_variable;
 565 #else
 566         return PAGE_ALIGN(stack_top) - random_variable;
 567 #endif
 568 }
 569
 570 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 571 {
 572         struct file *interpreter = NULL; /* to shut gcc up */
 573         unsigned long load_addr = 0, load_bias = 0;
 574         int load_addr_set = 0;
 575         char * elf_interpreter = NULL;
 576         unsigned long error;
 577         struct elf_phdr *elf_ppnt, *elf_phdata;
 578         unsigned long elf_bss, elf_brk;
 579         int elf_exec_fileno;
 580         int retval, i;
 581         unsigned int size;
 582         unsigned long elf_entry;
 583         unsigned long interp_load_addr = 0;
 584         unsigned long start_code, end_code, start_data, end_data;
 585         unsigned long reloc_func_desc = 0;
 586         int executable_stack = EXSTACK_DEFAULT;
 587         unsigned long def_flags = 0;
 588         struct {
 589                 struct elfhdr elf_ex;
 590                 struct elfhdr interp_elf_ex;
 591         } *loc;
 592
 593         loc = kmalloc(sizeof(*loc), GFP_KERNEL);
 594         if (!loc) {
 595                 retval = -ENOMEM;
 596                 goto out_ret;
 597         }
 598
 599         /* Get the exec-header */
 600         loc->elf_ex = *((struct elfhdr *)bprm->buf);
 601
 602         retval = -ENOEXEC;
 603         /* First of all, some simple consistency checks */
 604         if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 605                 goto out;
 606
 607         if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
 608                 goto out;
 609         if (!elf_check_arch(&loc->elf_ex))
 610                 goto out;
 611         if (!bprm->file->f_op||!bprm->file->f_op->mmap)
 612                 goto out;
 613
 614         /* Now read in all of the header information */
 615         if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
 616                 goto out;
 617         if (loc->elf_ex.e_phnum < 1 ||
 618                 loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
 619                 goto out;
 620         size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
 621         retval = -ENOMEM;
 622         elf_phdata = kmalloc(size, GFP_KERNEL);
 623         if (!elf_phdata)
 624                 goto out;
 625
 626         retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
 627                              (char *)elf_phdata, size);
 628         if (retval != size) {
 629                 if (retval >= 0)
 630                         retval = -EIO;
 631                 goto out_free_ph;
 632         }
 633
 634         retval = get_unused_fd();
 635         if (retval < 0)
 636                 goto out_free_ph;
 637         get_file(bprm->file);
 638         fd_install(elf_exec_fileno = retval, bprm->file);
 639
 640         elf_ppnt = elf_phdata;
 641         elf_bss = 0;
 642         elf_brk = 0;
 643
 644         start_code = ~0UL;
 645         end_code = 0;
 646         start_data = 0;
 647         end_data = 0;
 648
 649         for (i = 0; i < loc->elf_ex.e_phnum; i++) {
 650                 if (elf_ppnt->p_type == PT_INTERP) {
 651                         /* This is the program interpreter used for
 652                          * shared libraries - for now assume that this
 653                          * is an a.out format binary
 654                          */
 655                         retval = -ENOEXEC;
 656                         if (elf_ppnt->p_filesz > PATH_MAX ||
 657                             elf_ppnt->p_filesz < 2)
 658                                 goto out_free_file;
 659
 660                         retval = -ENOMEM;
 661                         elf_interpreter = kmalloc(elf_ppnt->p_filesz,
 662                                                   GFP_KERNEL);
 663                         if (!elf_interpreter)
 664                                 goto out_free_file;
 665
 666                         retval = kernel_read(bprm->file, elf_ppnt->p_offset,
 667                                              elf_interpreter,
 668                                              elf_ppnt->p_filesz);
 669                         if (retval != elf_ppnt->p_filesz) {
 670                                 if (retval >= 0)
 671                                         retval = -EIO;
 672                                 goto out_free_interp;
 673                         }
 674                         /* make sure path is NULL terminated */
 675                         retval = -ENOEXEC;
 676                         if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
 677                                 goto out_free_interp;
 678
 679                         /*
 680                          * The early SET_PERSONALITY here is so that the lookup
 681                          * for the interpreter happens in the namespace of the
 682                          * to-be-execed image.  SET_PERSONALITY can select an
 683                          * alternate root.
 684                          *
 685                          * However, SET_PERSONALITY is NOT allowed to switch
 686                          * this task into the new images's memory mapping
 687                          * policy - that is, TASK_SIZE must still evaluate to
 688                          * that which is appropriate to the execing application.
 689                          * This is because exit_mmap() needs to have TASK_SIZE
 690                          * evaluate to the size of the old image.
 691                          *
 692                          * So if (say) a 64-bit application is execing a 32-bit
 693                          * application it is the architecture's responsibility
 694                          * to defer changing the value of TASK_SIZE until the
 695                          * switch really is going to happen - do this in
 696                          * flush_thread().      - akpm
 697                          */
 698                         SET_PERSONALITY(loc->elf_ex);
 699
 700                         interpreter = open_exec(elf_interpreter);
 701                         retval = PTR_ERR(interpreter);
 702                         if (IS_ERR(interpreter))
 703                                 goto out_free_interp;
 704
 705                         /*
 706                          * If the binary is not readable then enforce
 707                          * mm->dumpable = 0 regardless of the interpreter's
 708                          * permissions.
 709                          */
 710                         if (file_permission(interpreter, MAY_READ) < 0)
 711                                 bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
 712
 713                         retval = kernel_read(interpreter, 0, bprm->buf,
 714                                              BINPRM_BUF_SIZE);
 715                         if (retval != BINPRM_BUF_SIZE) {
 716                                 if (retval >= 0)
 717                                         retval = -EIO;
 718                                 goto out_free_dentry;
 719                         }
 720
 721                         /* Get the exec headers */
 722                         loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
 723                         break;
 724                 }
 725                 elf_ppnt++;
 726         }
 727
 728         elf_ppnt = elf_phdata;
 729         for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
 730                 if (elf_ppnt->p_type == PT_GNU_STACK) {
 731                         if (elf_ppnt->p_flags & PF_X)
 732                                 executable_stack = EXSTACK_ENABLE_X;
 733                         else
 734                                 executable_stack = EXSTACK_DISABLE_X;
 735                         break;
 736                 }
 737
 738         /* Some simple consistency checks for the interpreter */
 739         if (elf_interpreter) {
 740                 retval = -ELIBBAD;
 741                 /* Not an ELF interpreter */
 742                 if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 743                         goto out_free_dentry;
 744                 /* Verify the interpreter has a valid arch */
 745                 if (!elf_check_arch(&loc->interp_elf_ex))
 746                         goto out_free_dentry;
 747         } else {
 748                 /* Executables without an interpreter also need a personality  */
 749                 SET_PERSONALITY(loc->elf_ex);
 750         }
 751
 752         /* Flush all traces of the currently running executable */
 753         retval = flush_old_exec(bprm);
 754         if (retval)
 755                 goto out_free_dentry;
 756
 757         /* OK, This is the point of no return */
 758         current->flags &= ~PF_FORKNOEXEC;
 759         current->mm->def_flags = def_flags;
 760
 761         /* Do this immediately, since STACK_TOP as used in setup_arg_pages
 762            may depend on the personality.  */
 763         SET_PERSONALITY(loc->elf_ex);
 764         if (elf_read_implies_exec(loc->elf_ex, executable_stack))
 765                 current->personality |= READ_IMPLIES_EXEC;
 766
 767         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 768                 current->flags |= PF_RANDOMIZE;
 769         arch_pick_mmap_layout(current->mm);
 770
 771         /* Do this so that we can load the interpreter, if need be.  We will
 772            change some of these later */
 773         current->mm->free_area_cache = current->mm->mmap_base;
 774         current->mm->cached_hole_size = 0;
 775         retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
 776                                  executable_stack);
 777         if (retval < 0) {
 778                 send_sig(SIGKILL, current, 0);
 779                 goto out_free_dentry;
 780         }
 781
 782         current->mm->start_stack = bprm->p;
 783
 784         /* Now we do a little grungy work by mmaping the ELF image into
 785            the correct location in memory. */
 786         for(i = 0, elf_ppnt = elf_phdata;
 787             i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
 788                 int elf_prot = 0, elf_flags;
 789                 unsigned long k, vaddr;
 790
 791                 if (elf_ppnt->p_type != PT_LOAD)
 792                         continue;
 793
 794                 if (unlikely (elf_brk > elf_bss)) {
 795                         unsigned long nbyte;
 796
 797                         /* There was a PT_LOAD segment with p_memsz > p_filesz
 798                            before this one. Map anonymous pages, if needed,
 799                            and clear the area.  */
 800                         retval = set_brk (elf_bss + load_bias,
 801                                           elf_brk + load_bias);
 802                         if (retval) {
 803                                 send_sig(SIGKILL, current, 0);
 804                                 goto out_free_dentry;
 805                         }
 806                         nbyte = ELF_PAGEOFFSET(elf_bss);
 807                         if (nbyte) {
 808                                 nbyte = ELF_MIN_ALIGN - nbyte;
 809                                 if (nbyte > elf_brk - elf_bss)
 810                                         nbyte = elf_brk - elf_bss;
 811                                 if (clear_user((void __user *)elf_bss +
 812                                                         load_bias, nbyte)) {
 813                                         /*
 814                                          * This bss-zeroing can fail if the ELF
 815                                          * file specifies odd protections. So
 816                                          * we don't check the return value
 817                                          */
 818                                 }
 819                         }
 820                 }
 821
 822                 if (elf_ppnt->p_flags & PF_R)
 823                         elf_prot |= PROT_READ;
 824                 if (elf_ppnt->p_flags & PF_W)
 825                         elf_prot |= PROT_WRITE;
 826                 if (elf_ppnt->p_flags & PF_X)
 827                         elf_prot |= PROT_EXEC;
 828
 829                 elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
 830
 831                 vaddr = elf_ppnt->p_vaddr;
 832                 if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
 833                         elf_flags |= MAP_FIXED;
 834                 } else if (loc->elf_ex.e_type == ET_DYN) {
 835                         /* Try and get dynamic programs out of the way of the
 836                          * default mmap base, as well as whatever program they
 837                          * might try to exec.  This is because the brk will
 838                          * follow the loader, and is not movable.  */
 839 #ifdef CONFIG_X86
 840                         load_bias = 0;
 841 #else
 842                         load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
 843 #endif
 844                 }
 845
 846                 error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
 847                                 elf_prot, elf_flags, 0);
 848                 if (BAD_ADDR(error)) {
 849                         send_sig(SIGKILL, current, 0);
 850                         retval = IS_ERR((void *)error) ?
 851                                 PTR_ERR((void*)error) : -EINVAL;
 852                         goto out_free_dentry;
 853                 }
 854
 855                 if (!load_addr_set) {
 856                         load_addr_set = 1;
 857                         load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
 858                         if (loc->elf_ex.e_type == ET_DYN) {
 859                                 load_bias += error -
 860                                              ELF_PAGESTART(load_bias + vaddr);
 861                                 load_addr += load_bias;
 862                                 reloc_func_desc = load_bias;
 863                         }
 864                 }
 865                 k = elf_ppnt->p_vaddr;
 866                 if (k < start_code)
 867                         start_code = k;
 868                 if (start_data < k)
 869                         start_data = k;
 870
 871                 /*
 872                  * Check to see if the section's size will overflow the
 873                  * allowed task size. Note that p_filesz must always be
 874                  * <= p_memsz so it is only necessary to check p_memsz.
 875                  */
 876                 if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
 877                     elf_ppnt->p_memsz > TASK_SIZE ||
 878                     TASK_SIZE - elf_ppnt->p_memsz < k) {
 879                         /* set_brk can never work. Avoid overflows. */
 880                         send_sig(SIGKILL, current, 0);
 881                         retval = -EINVAL;
 882                         goto out_free_dentry;
 883                 }
 884
 885                 k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
 886
 887                 if (k > elf_bss)
 888                         elf_bss = k;
 889                 if ((elf_ppnt->p_flags & PF_X) && end_code < k)
 890                         end_code = k;
 891                 if (end_data < k)
 892                         end_data = k;
 893                 k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
 894                 if (k > elf_brk)
 895                         elf_brk = k;
 896         }
 897
 898         loc->elf_ex.e_entry += load_bias;
 899         elf_bss += load_bias;
 900         elf_brk += load_bias;
 901         start_code += load_bias;
 902         end_code += load_bias;
 903         start_data += load_bias;
 904         end_data += load_bias;
 905
 906         /* Calling set_brk effectively mmaps the pages that we need
 907          * for the bss and break sections.  We must do this before
 908          * mapping in the interpreter, to make sure it doesn't wind
 909          * up getting placed where the bss needs to go.
 910          */
 911         retval = set_brk(elf_bss, elf_brk);
 912         if (retval) {
 913                 send_sig(SIGKILL, current, 0);
 914                 goto out_free_dentry;
 915         }
 916         if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
 917                 send_sig(SIGSEGV, current, 0);
 918                 retval = -EFAULT; /* Nobody gets to see this, but.. */
 919                 goto out_free_dentry;
 920         }
 921
 922         if (elf_interpreter) {
 923                 unsigned long uninitialized_var(interp_map_addr);
 924
 925                 elf_entry = load_elf_interp(&loc->interp_elf_ex,
 926                                             interpreter,
 927                                             &interp_map_addr,
 928                                             load_bias);
 929                 if (!IS_ERR((void *)elf_entry)) {
 930                         /*
 931                          * load_elf_interp() returns relocation
 932                          * adjustment
 933                          */
 934                         interp_load_addr = elf_entry;
 935                         elf_entry += loc->interp_elf_ex.e_entry;
 936                 }
 937                 if (BAD_ADDR(elf_entry)) {
 938                         force_sig(SIGSEGV, current);
 939                         retval = IS_ERR((void *)elf_entry) ?
 940                                         (int)elf_entry : -EINVAL;
 941                         goto out_free_dentry;
 942                 }
 943                 reloc_func_desc = interp_load_addr;
 944
 945                 allow_write_access(interpreter);
 946                 fput(interpreter);
 947                 kfree(elf_interpreter);
 948         } else {
 949                 elf_entry = loc->elf_ex.e_entry;
 950                 if (BAD_ADDR(elf_entry)) {
 951                         force_sig(SIGSEGV, current);
 952                         retval = -EINVAL;
 953                         goto out_free_dentry;
 954                 }
 955         }
 956
 957         kfree(elf_phdata);
 958
 959         sys_close(elf_exec_fileno);
 960
 961         set_binfmt(&elf_format);
 962
 963 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 964         retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
 965         if (retval < 0) {
 966                 send_sig(SIGKILL, current, 0);
 967                 goto out;
 968         }
 969 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 970
 971         install_exec_creds(bprm);
 972         current->flags &= ~PF_FORKNOEXEC;
 973         retval = create_elf_tables(bprm, &loc->elf_ex,
 974                           load_addr, interp_load_addr);
 975         if (retval < 0) {
 976                 send_sig(SIGKILL, current, 0);
 977                 goto out;
 978         }
 979         /* N.B. passed_fileno might not be initialized? */
 980         current->mm->end_code = end_code;
 981         current->mm->start_code = start_code;
 982         current->mm->start_data = start_data;
 983         current->mm->end_data = end_data;
 984         current->mm->start_stack = bprm->p;
 985
 986 #ifdef arch_randomize_brk
 987         if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1))
 988                 current->mm->brk = current->mm->start_brk =
 989                         arch_randomize_brk(current->mm);
 990 #endif
 991
 992         if (current->personality & MMAP_PAGE_ZERO) {
 993                 /* Why this, you ask???  Well SVr4 maps page 0 as read-only,
 994                    and some applications "depend" upon this behavior.
 995                    Since we do not have the power to recompile these, we
 996                    emulate the SVr4 behavior. Sigh. */
 997                 down_write(&current->mm->mmap_sem);
 998                 error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
 999                                 MAP_FIXED | MAP_PRIVATE, 0);
1000                 up_write(&current->mm->mmap_sem);
1001         }
1002
1003 #ifdef ELF_PLAT_INIT
1004         /*
1005          * The ABI may specify that certain registers be set up in special
1006          * ways (on i386 %edx is the address of a DT_FINI function, for
1007          * example.  In addition, it may also specify (eg, PowerPC64 ELF)
1008          * that the e_entry field is the address of the function descriptor
1009          * for the startup routine, rather than the address of the startup
1010          * routine itself.  This macro performs whatever initialization to
1011          * the regs structure is required as well as any relocations to the
1012          * function descriptor entries when executing dynamically links apps.
1013          */
1014         ELF_PLAT_INIT(regs, reloc_func_desc);
1015 #endif
1016
1017         start_thread(regs, elf_entry, bprm->p);
1018         retval = 0;
1019 out:
1020         kfree(loc);
1021 out_ret:
1022         return retval;
1023
1024         /* error cleanup */
1025 out_free_dentry:
1026         allow_write_access(interpreter);
1027         if (interpreter)
1028                 fput(interpreter);
1029 out_free_interp:
1030         kfree(elf_interpreter);
1031 out_free_file:
1032         sys_close(elf_exec_fileno);
1033 out_free_ph:
1034         kfree(elf_phdata);
1035         goto out;
1036 }
1037
1038 /* This is really simpleminded and specialized - we are loading an
1039    a.out library that is given an ELF header. */
1040 static int load_elf_library(struct file *file)
1041 {
1042         struct elf_phdr *elf_phdata;
1043         struct elf_phdr *eppnt;
1044         unsigned long elf_bss, bss, len;
1045         int retval, error, i, j;
1046         struct elfhdr elf_ex;
1047
1048         error = -ENOEXEC;
1049         retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
1050         if (retval != sizeof(elf_ex))
1051                 goto out;
1052
1053         if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1054                 goto out;
1055
1056         /* First of all, some simple consistency checks */
1057         if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1058             !elf_check_arch(&elf_ex) || !file->f_op || !file->f_op->mmap)
1059                 goto out;
1060
1061         /* Now read in all of the header information */
1062
1063         j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1064         /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1065
1066         error = -ENOMEM;
1067         elf_phdata = kmalloc(j, GFP_KERNEL);
1068         if (!elf_phdata)
1069                 goto out;
1070
1071         eppnt = elf_phdata;
1072         error = -ENOEXEC;
1073         retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
1074         if (retval != j)
1075                 goto out_free_ph;
1076
1077         for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1078                 if ((eppnt + i)->p_type == PT_LOAD)
1079                         j++;
1080         if (j != 1)
1081                 goto out_free_ph;
1082
1083         while (eppnt->p_type != PT_LOAD)
1084                 eppnt++;
1085
1086         /* Now use mmap to map the library into memory. */
1087         down_write(&current->mm->mmap_sem);
1088         error = do_mmap(file,
1089                         ELF_PAGESTART(eppnt->p_vaddr),
1090                         (eppnt->p_filesz +
1091                          ELF_PAGEOFFSET(eppnt->p_vaddr)),
1092                         PROT_READ | PROT_WRITE | PROT_EXEC,
1093                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
1094                         (eppnt->p_offset -
1095                          ELF_PAGEOFFSET(eppnt->p_vaddr)));
1096         up_write(&current->mm->mmap_sem);
1097         if (error != ELF_PAGESTART(eppnt->p_vaddr))
1098                 goto out_free_ph;
1099
1100         elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
1101         if (padzero(elf_bss)) {
1102                 error = -EFAULT;
1103                 goto out_free_ph;
1104         }
1105
1106         len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
1107                             ELF_MIN_ALIGN - 1);
1108         bss = eppnt->p_memsz + eppnt->p_vaddr;
1109         if (bss > len) {
1110                 down_write(&current->mm->mmap_sem);
1111                 do_brk(len, bss - len);
1112                 up_write(&current->mm->mmap_sem);
1113         }
1114         error = 0;
1115
1116 out_free_ph:
1117         kfree(elf_phdata);
1118 out:
1119         return error;
1120 }
1121
1122 /*
1123  * Note that some platforms still use traditional core dumps and not
1124  * the ELF core dump.  Each platform can select it as appropriate.
1125  */
1126 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
1127
1128 /*
1129  * ELF core dumper
1130  *
1131  * Modelled on fs/exec.c:aout_core_dump()
1132  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1133  */
1134 /*
1135  * These are the only things you should do on a core-file: use only these
1136  * functions to write out all the necessary info.
1137  */
1138 static int dump_write(struct file *file, const void *addr, int nr)
1139 {
1140         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
1141 }
1142
1143 static int dump_seek(struct file *file, loff_t off)
1144 {
1145         if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
1146                 if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
1147                         return 0;
1148         } else {
1149                 char *buf = (char *)get_zeroed_page(GFP_KERNEL);
1150                 if (!buf)
1151                         return 0;
1152                 while (off > 0) {
1153                         unsigned long n = off;
1154                         if (n > PAGE_SIZE)
1155                                 n = PAGE_SIZE;
1156                         if (!dump_write(file, buf, n))
1157                                 return 0;
1158                         off -= n;
1159                 }
1160                 free_page((unsigned long)buf);
1161         }
1162         return 1;
1163 }
1164
1165 /*
1166  * Decide what to dump of a segment, part, all or none.
1167  */
1168 static unsigned long vma_dump_size(struct vm_area_struct *vma,
1169                                    unsigned long mm_flags)
1170 {
1171 #define FILTER(type)    (mm_flags & (1UL << MMF_DUMP_##type))
1172
1173         /* The vma can be set up to tell us the answer directly.  */
1174         if (vma->vm_flags & VM_ALWAYSDUMP)
1175                 goto whole;
1176
1177         /* Hugetlb memory check */
1178         if (vma->vm_flags & VM_HUGETLB) {
1179                 if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
1180                         goto whole;
1181                 if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
1182                         goto whole;
1183         }
1184
1185         /* Do not dump I/O mapped devices or special mappings */
1186         if (vma->vm_flags & (VM_IO | VM_RESERVED))
1187                 return 0;
1188
1189         /* By default, dump shared memory if mapped from an anonymous file. */
1190         if (vma->vm_flags & VM_SHARED) {
1191                 if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ?
1192                     FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
1193                         goto whole;
1194                 return 0;
1195         }
1196
1197         /* Dump segments that have been written to.  */
1198         if (vma->anon_vma && FILTER(ANON_PRIVATE))
1199                 goto whole;
1200         if (vma->vm_file == NULL)
1201                 return 0;
1202
1203         if (FILTER(MAPPED_PRIVATE))
1204                 goto whole;
1205
1206         /*
1207          * If this looks like the beginning of a DSO or executable mapping,
1208          * check for an ELF header.  If we find one, dump the first page to
1209          * aid in determining what was mapped here.
1210          */
1211         if (FILTER(ELF_HEADERS) &&
1212             vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
1213                 u32 __user *header = (u32 __user *) vma->vm_start;
1214                 u32 word;
1215                 mm_segment_t fs = get_fs();
1216                 /*
1217                  * Doing it this way gets the constant folded by GCC.
1218                  */
1219                 union {
1220                         u32 cmp;
1221                         char elfmag[SELFMAG];
1222                 } magic;
1223                 BUILD_BUG_ON(SELFMAG != sizeof word);
1224                 magic.elfmag[EI_MAG0] = ELFMAG0;
1225                 magic.elfmag[EI_MAG1] = ELFMAG1;
1226                 magic.elfmag[EI_MAG2] = ELFMAG2;
1227                 magic.elfmag[EI_MAG3] = ELFMAG3;
1228                 /*
1229                  * Switch to the user "segment" for get_user(),
1230                  * then put back what elf_core_dump() had in place.
1231                  */
1232                 set_fs(USER_DS);
1233                 if (unlikely(get_user(word, header)))
1234                         word = 0;
1235                 set_fs(fs);
1236                 if (word == magic.cmp)
1237                         return PAGE_SIZE;
1238         }
1239
1240 #undef  FILTER
1241
1242         return 0;
1243
1244 whole:
1245         return vma->vm_end - vma->vm_start;
1246 }
1247
1248 /* An ELF note in memory */
1249 struct memelfnote
1250 {
1251         const char *name;
1252         int type;
1253         unsigned int datasz;
1254         void *data;
1255 };
1256
1257 static int notesize(struct memelfnote *en)
1258 {
1259         int sz;
1260
1261         sz = sizeof(struct elf_note);
1262         sz += roundup(strlen(en->name) + 1, 4);
1263         sz += roundup(en->datasz, 4);
1264
1265         return sz;
1266 }
1267
1268 #define DUMP_WRITE(addr, nr, foffset)   \
1269         do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
1270
1271 static int alignfile(struct file *file, loff_t *foffset)
1272 {
1273         static const char buf[4] = { 0, };
1274         DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
1275         return 1;
1276 }
1277
1278 static int writenote(struct memelfnote *men, struct file *file,
1279                         loff_t *foffset)
1280 {
1281         struct elf_note en;
1282         en.n_namesz = strlen(men->name) + 1;
1283         en.n_descsz = men->datasz;
1284         en.n_type = men->type;
1285
1286         DUMP_WRITE(&en, sizeof(en), foffset);
1287         DUMP_WRITE(men->name, en.n_namesz, foffset);
1288         if (!alignfile(file, foffset))
1289                 return 0;
1290         DUMP_WRITE(men->data, men->datasz, foffset);
1291         if (!alignfile(file, foffset))
1292                 return 0;
1293
1294         return 1;
1295 }
1296 #undef DUMP_WRITE
1297
1298 #define DUMP_WRITE(addr, nr)    \
1299         if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
1300                 goto end_coredump;
1301 #define DUMP_SEEK(off)  \
1302         if (!dump_seek(file, (off))) \
1303                 goto end_coredump;
1304
1305 static void fill_elf_header(struct elfhdr *elf, int segs,
1306                             u16 machine, u32 flags, u8 osabi)
1307 {
1308         memset(elf, 0, sizeof(*elf));
1309
1310         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1311         elf->e_ident[EI_CLASS] = ELF_CLASS;
1312         elf->e_ident[EI_DATA] = ELF_DATA;
1313         elf->e_ident[EI_VERSION] = EV_CURRENT;
1314         elf->e_ident[EI_OSABI] = ELF_OSABI;
1315
1316         elf->e_type = ET_CORE;
1317         elf->e_machine = machine;
1318         elf->e_version = EV_CURRENT;
1319         elf->e_phoff = sizeof(struct elfhdr);
1320         elf->e_flags = flags;
1321         elf->e_ehsize = sizeof(struct elfhdr);
1322         elf->e_phentsize = sizeof(struct elf_phdr);
1323         elf->e_phnum = segs;
1324
1325         return;
1326 }
1327
1328 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1329 {
1330         phdr->p_type = PT_NOTE;
1331         phdr->p_offset = offset;
1332         phdr->p_vaddr = 0;
1333         phdr->p_paddr = 0;
1334         phdr->p_filesz = sz;
1335         phdr->p_memsz = 0;
1336         phdr->p_flags = 0;
1337         phdr->p_align = 0;
1338         return;
1339 }
1340
1341 static void fill_note(struct memelfnote *note, const char *name, int type,
1342                 unsigned int sz, void *data)
1343 {
1344         note->name = name;
1345         note->type = type;
1346         note->datasz = sz;
1347         note->data = data;
1348         return;
1349 }
1350
1351 /*
1352  * fill up all the fields in prstatus from the given task struct, except
1353  * registers which need to be filled up separately.
1354  */
1355 static void fill_prstatus(struct elf_prstatus *prstatus,
1356                 struct task_struct *p, long signr)
1357 {
1358         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1359         prstatus->pr_sigpend = p->pending.signal.sig[0];
1360         prstatus->pr_sighold = p->blocked.sig[0];
1361         prstatus->pr_pid = task_pid_vnr(p);
1362         prstatus->pr_ppid = task_pid_vnr(p->real_parent);
1363         prstatus->pr_pgrp = task_pgrp_vnr(p);
1364         prstatus->pr_sid = task_session_vnr(p);
1365         if (thread_group_leader(p)) {
1366                 struct task_cputime cputime;
1367
1368                 /*
1369                  * This is the record for the group leader.  It shows the
1370                  * group-wide total, not its individual thread total.
1371                  */
1372                 thread_group_cputime(p, &cputime);
1373                 cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1374                 cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1375         } else {
1376                 cputime_to_timeval(p->utime, &prstatus->pr_utime);
1377                 cputime_to_timeval(p->stime, &prstatus->pr_stime);
1378         }
1379         cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1380         cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1381 }
1382
1383 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1384                        struct mm_struct *mm)
1385 {
1386         const struct cred *cred;
1387         unsigned int i, len;
1388
1389         /* first copy the parameters from user space */
1390         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1391
1392         len = mm->arg_end - mm->arg_start;
1393         if (len >= ELF_PRARGSZ)
1394                 len = ELF_PRARGSZ-1;
1395         if (copy_from_user(&psinfo->pr_psargs,
1396                            (const char __user *)mm->arg_start, len))
1397                 return -EFAULT;
1398         for(i = 0; i < len; i++)
1399                 if (psinfo->pr_psargs[i] == 0)
1400                         psinfo->pr_psargs[i] = ' ';
1401         psinfo->pr_psargs[len] = 0;
1402
1403         psinfo->pr_pid = task_pid_vnr(p);
1404         psinfo->pr_ppid = task_pid_vnr(p->real_parent);
1405         psinfo->pr_pgrp = task_pgrp_vnr(p);
1406         psinfo->pr_sid = task_session_vnr(p);
1407
1408         i = p->state ? ffz(~p->state) + 1 : 0;
1409         psinfo->pr_state = i;
1410         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1411         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1412         psinfo->pr_nice = task_nice(p);
1413         psinfo->pr_flag = p->flags;
1414         rcu_read_lock();
1415         cred = __task_cred(p);
1416         SET_UID(psinfo->pr_uid, cred->uid);
1417         SET_GID(psinfo->pr_gid, cred->gid);
1418         rcu_read_unlock();
1419         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1420
1421         return 0;
1422 }
1423
1424 static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
1425 {
1426         elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
1427         int i = 0;
1428         do
1429                 i += 2;
1430         while (auxv[i - 2] != AT_NULL);
1431         fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
1432 }
1433
1434 #ifdef CORE_DUMP_USE_REGSET
1435 #include <linux/regset.h>
1436
1437 struct elf_thread_core_info {
1438         struct elf_thread_core_info *next;
1439         struct task_struct *task;
1440         struct elf_prstatus prstatus;
1441         struct memelfnote notes[0];
1442 };
1443
1444 struct elf_note_info {
1445         struct elf_thread_core_info *thread;
1446         struct memelfnote psinfo;
1447         struct memelfnote auxv;
1448         size_t size;
1449         int thread_notes;
1450 };
1451
1452 /*
1453  * When a regset has a writeback hook, we call it on each thread before
1454  * dumping user memory.  On register window machines, this makes sure the
1455  * user memory backing the register data is up to date before we read it.
1456  */
1457 static void do_thread_regset_writeback(struct task_struct *task,
1458                                        const struct user_regset *regset)
1459 {
1460         if (regset->writeback)
1461                 regset->writeback(task, regset, 1);
1462 }
1463
1464 static int fill_thread_core_info(struct elf_thread_core_info *t,
1465                                  const struct user_regset_view *view,
1466                                  long signr, size_t *total)
1467 {
1468         unsigned int i;
1469
1470         /*
1471          * NT_PRSTATUS is the one special case, because the regset data
1472          * goes into the pr_reg field inside the note contents, rather
1473          * than being the whole note contents.  We fill the reset in here.
1474          * We assume that regset 0 is NT_PRSTATUS.
1475          */
1476         fill_prstatus(&t->prstatus, t->task, signr);
1477         (void) view->regsets[0].get(t->task, &view->regsets[0],
1478                                     0, sizeof(t->prstatus.pr_reg),
1479                                     &t->prstatus.pr_reg, NULL);
1480
1481         fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
1482                   sizeof(t->prstatus), &t->prstatus);
1483         *total += notesize(&t->notes[0]);
1484
1485         do_thread_regset_writeback(t->task, &view->regsets[0]);
1486
1487         /*
1488          * Each other regset might generate a note too.  For each regset
1489          * that has no core_note_type or is inactive, we leave t->notes[i]
1490          * all zero and we'll know to skip writing it later.
1491          */
1492         for (i = 1; i < view->n; ++i) {
1493                 const struct user_regset *regset = &view->regsets[i];
1494                 do_thread_regset_writeback(t->task, regset);
1495                 if (regset->core_note_type &&
1496                     (!regset->active || regset->active(t->task, regset))) {
1497                         int ret;
1498                         size_t size = regset->n * regset->size;
1499                         void *data = kmalloc(size, GFP_KERNEL);
1500                         if (unlikely(!data))
1501                                 return 0;
1502                         ret = regset->get(t->task, regset,
1503                                           0, size, data, NULL);
1504                         if (unlikely(ret))
1505                                 kfree(data);
1506                         else {
1507                                 if (regset->core_note_type != NT_PRFPREG)
1508                                         fill_note(&t->notes[i], "LINUX",
1509                                                   regset->core_note_type,
1510                                                   size, data);
1511                                 else {
1512                                         t->prstatus.pr_fpvalid = 1;
1513                                         fill_note(&t->notes[i], "CORE",
1514                                                   NT_PRFPREG, size, data);
1515                                 }
1516                                 *total += notesize(&t->notes[i]);
1517                         }
1518                 }
1519         }
1520
1521         return 1;
1522 }
1523
1524 static int fill_note_info(struct elfhdr *elf, int phdrs,
1525                           struct elf_note_info *info,
1526                           long signr, struct pt_regs *regs)
1527 {
1528         struct task_struct *dump_task = current;
1529         const struct user_regset_view *view = task_user_regset_view(dump_task);
1530         struct elf_thread_core_info *t;
1531         struct elf_prpsinfo *psinfo;
1532         struct core_thread *ct;
1533         unsigned int i;
1534
1535         info->size = 0;
1536         info->thread = NULL;
1537
1538         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1539         fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1540
1541         if (psinfo == NULL)
1542                 return 0;
1543
1544         /*
1545          * Figure out how many notes we're going to need for each thread.
1546          */
1547         info->thread_notes = 0;
1548         for (i = 0; i < view->n; ++i)
1549                 if (view->regsets[i].core_note_type != 0)
1550                         ++info->thread_notes;
1551
1552         /*
1553          * Sanity check.  We rely on regset 0 being in NT_PRSTATUS,
1554          * since it is our one special case.
1555          */
1556         if (unlikely(info->thread_notes == 0) ||
1557             unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
1558                 WARN_ON(1);
1559                 return 0;
1560         }
1561
1562         /*
1563          * Initialize the ELF file header.
1564          */
1565         fill_elf_header(elf, phdrs,
1566                         view->e_machine, view->e_flags, view->ei_osabi);
1567
1568         /*
1569          * Allocate a structure for each thread.
1570          */
1571         for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
1572                 t = kzalloc(offsetof(struct elf_thread_core_info,
1573                                      notes[info->thread_notes]),
1574                             GFP_KERNEL);
1575                 if (unlikely(!t))
1576                         return 0;
1577
1578                 t->task = ct->task;
1579                 if (ct->task == dump_task || !info->thread) {
1580                         t->next = info->thread;
1581                         info->thread = t;
1582                 } else {
1583                         /*
1584                          * Make sure to keep the original task at
1585                          * the head of the list.
1586                          */
1587                         t->next = info->thread->next;
1588                         info->thread->next = t;
1589                 }
1590         }
1591
1592         /*
1593          * Now fill in each thread's information.
1594          */
1595         for (t = info->thread; t != NULL; t = t->next)
1596                 if (!fill_thread_core_info(t, view, signr, &info->size))
1597                         return 0;
1598
1599         /*
1600          * Fill in the two process-wide notes.
1601          */
1602         fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
1603         info->size += notesize(&info->psinfo);
1604
1605         fill_auxv_note(&info->auxv, current->mm);
1606         info->size += notesize(&info->auxv);
1607
1608         return 1;
1609 }
1610
1611 static size_t get_note_info_size(struct elf_note_info *info)
1612 {
1613         return info->size;
1614 }
1615
1616 /*
1617  * Write all the notes for each thread.  When writing the first thread, the
1618  * process-wide notes are interleaved after the first thread-specific note.
1619  */
1620 static int write_note_info(struct elf_note_info *info,
1621                            struct file *file, loff_t *foffset)
1622 {
1623         bool first = 1;
1624         struct elf_thread_core_info *t = info->thread;
1625
1626         do {
1627                 int i;
1628
1629                 if (!writenote(&t->notes[0], file, foffset))
1630                         return 0;
1631
1632                 if (first && !writenote(&info->psinfo, file, foffset))
1633                         return 0;
1634                 if (first && !writenote(&info->auxv, file, foffset))
1635                         return 0;
1636
1637                 for (i = 1; i < info->thread_notes; ++i)
1638                         if (t->notes[i].data &&
1639                             !writenote(&t->notes[i], file, foffset))
1640                                 return 0;
1641
1642                 first = 0;
1643                 t = t->next;
1644         } while (t);
1645
1646         return 1;
1647 }
1648
1649 static void free_note_info(struct elf_note_info *info)
1650 {
1651         struct elf_thread_core_info *threads = info->thread;
1652         while (threads) {
1653                 unsigned int i;
1654                 struct elf_thread_core_info *t = threads;
1655                 threads = t->next;
1656                 WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
1657                 for (i = 1; i < info->thread_notes; ++i)
1658                         kfree(t->notes[i].data);
1659                 kfree(t);
1660         }
1661         kfree(info->psinfo.data);
1662 }
1663
1664 #else
1665
1666 /* Here is the structure in which status of each thread is captured. */
1667 struct elf_thread_status
1668 {
1669         struct list_head list;
1670         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1671         elf_fpregset_t fpu;             /* NT_PRFPREG */
1672         struct task_struct *thread;
1673 #ifdef ELF_CORE_COPY_XFPREGS
1674         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1675 #endif
1676         struct memelfnote notes[3];
1677         int num_notes;
1678 };
1679
1680 /*
1681  * In order to add the specific thread information for the elf file format,
1682  * we need to keep a linked list of every threads pr_status and then create
1683  * a single section for them in the final core file.
1684  */
1685 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1686 {
1687         int sz = 0;
1688         struct task_struct *p = t->thread;
1689         t->num_notes = 0;
1690
1691         fill_prstatus(&t->prstatus, p, signr);
1692         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1693
1694         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1695                   &(t->prstatus));
1696         t->num_notes++;
1697         sz += notesize(&t->notes[0]);
1698
1699         if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
1700                                                                 &t->fpu))) {
1701                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1702                           &(t->fpu));
1703                 t->num_notes++;
1704                 sz += notesize(&t->notes[1]);
1705         }
1706
1707 #ifdef ELF_CORE_COPY_XFPREGS
1708         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1709                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1710                           sizeof(t->xfpu), &t->xfpu);
1711                 t->num_notes++;
1712                 sz += notesize(&t->notes[2]);
1713         }
1714 #endif
1715         return sz;
1716 }
1717
1718 struct elf_note_info {
1719         struct memelfnote *notes;
1720         struct elf_prstatus *prstatus;  /* NT_PRSTATUS */
1721         struct elf_prpsinfo *psinfo;    /* NT_PRPSINFO */
1722         struct list_head thread_list;
1723         elf_fpregset_t *fpu;
1724 #ifdef ELF_CORE_COPY_XFPREGS
1725         elf_fpxregset_t *xfpu;
1726 #endif
1727         int thread_status_size;
1728         int numnote;
1729 };
1730
1731 static int fill_note_info(struct elfhdr *elf, int phdrs,
1732                           struct elf_note_info *info,
1733                           long signr, struct pt_regs *regs)
1734 {
1735 #define NUM_NOTES       6
1736         struct list_head *t;
1737
1738         info->notes = NULL;
1739         info->prstatus = NULL;
1740         info->psinfo = NULL;
1741         info->fpu = NULL;
1742 #ifdef ELF_CORE_COPY_XFPREGS
1743         info->xfpu = NULL;
1744 #endif
1745         INIT_LIST_HEAD(&info->thread_list);
1746
1747         info->notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote),
1748                               GFP_KERNEL);
1749         if (!info->notes)
1750                 return 0;
1751         info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
1752         if (!info->psinfo)
1753                 return 0;
1754         info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
1755         if (!info->prstatus)
1756                 return 0;
1757         info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
1758         if (!info->fpu)
1759                 return 0;
1760 #ifdef ELF_CORE_COPY_XFPREGS
1761         info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
1762         if (!info->xfpu)
1763                 return 0;
1764 #endif
1765
1766         info->thread_status_size = 0;
1767         if (signr) {
1768                 struct core_thread *ct;
1769                 struct elf_thread_status *ets;
1770
1771                 for (ct = current->mm->core_state->dumper.next;
1772                                                 ct; ct = ct->next) {
1773                         ets = kzalloc(sizeof(*ets), GFP_KERNEL);
1774                         if (!ets)
1775                                 return 0;
1776
1777                         ets->thread = ct->task;
1778                         list_add(&ets->list, &info->thread_list);
1779                 }
1780
1781                 list_for_each(t, &info->thread_list) {
1782                         int sz;
1783
1784                         ets = list_entry(t, struct elf_thread_status, list);
1785                         sz = elf_dump_thread_status(signr, ets);
1786                         info->thread_status_size += sz;
1787                 }
1788         }
1789         /* now collect the dump for the current */
1790         memset(info->prstatus, 0, sizeof(*info->prstatus));
1791         fill_prstatus(info->prstatus, current, signr);
1792         elf_core_copy_regs(&info->prstatus->pr_reg, regs);
1793
1794         /* Set up header */
1795         fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS, ELF_OSABI);
1796
1797         /*
1798          * Set up the notes in similar form to SVR4 core dumps made
1799          * with info from their /proc.
1800          */
1801
1802         fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
1803                   sizeof(*info->prstatus), info->prstatus);
1804         fill_psinfo(info->psinfo, current->group_leader, current->mm);
1805         fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
1806                   sizeof(*info->psinfo), info->psinfo);
1807
1808         info->numnote = 2;
1809
1810         fill_auxv_note(&info->notes[info->numnote++], current->mm);
1811
1812         /* Try to dump the FPU. */
1813         info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs,
1814                                                                info->fpu);
1815         if (info->prstatus->pr_fpvalid)
1816                 fill_note(info->notes + info->numnote++,
1817                           "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
1818 #ifdef ELF_CORE_COPY_XFPREGS
1819         if (elf_core_copy_task_xfpregs(current, info->xfpu))
1820                 fill_note(info->notes + info->numnote++,
1821                           "LINUX", ELF_CORE_XFPREG_TYPE,
1822                           sizeof(*info->xfpu), info->xfpu);
1823 #endif
1824
1825         return 1;
1826
1827 #undef NUM_NOTES
1828 }
1829
1830 static size_t get_note_info_size(struct elf_note_info *info)
1831 {
1832         int sz = 0;
1833         int i;
1834
1835         for (i = 0; i < info->numnote; i++)
1836                 sz += notesize(info->notes + i);
1837
1838         sz += info->thread_status_size;
1839
1840         return sz;
1841 }
1842
1843 static int write_note_info(struct elf_note_info *info,
1844                            struct file *file, loff_t *foffset)
1845 {
1846         int i;
1847         struct list_head *t;
1848
1849         for (i = 0; i < info->numnote; i++)
1850                 if (!writenote(info->notes + i, file, foffset))
1851                         return 0;
1852
1853         /* write out the thread status notes section */
1854         list_for_each(t, &info->thread_list) {
1855                 struct elf_thread_status *tmp =
1856                                 list_entry(t, struct elf_thread_status, list);
1857
1858                 for (i = 0; i < tmp->num_notes; i++)
1859                         if (!writenote(&tmp->notes[i], file, foffset))
1860                                 return 0;
1861         }
1862
1863         return 1;
1864 }
1865
1866 static void free_note_info(struct elf_note_info *info)
1867 {
1868         while (!list_empty(&info->thread_list)) {
1869                 struct list_head *tmp = info->thread_list.next;
1870                 list_del(tmp);
1871                 kfree(list_entry(tmp, struct elf_thread_status, list));
1872         }
1873
1874         kfree(info->prstatus);
1875         kfree(info->psinfo);
1876         kfree(info->notes);
1877         kfree(info->fpu);
1878 #ifdef ELF_CORE_COPY_XFPREGS
1879         kfree(info->xfpu);
1880 #endif
1881 }
1882
1883 #endif
1884
1885 static struct vm_area_struct *first_vma(struct task_struct *tsk,
1886                                         struct vm_area_struct *gate_vma)
1887 {
1888         struct vm_area_struct *ret = tsk->mm->mmap;
1889
1890         if (ret)
1891                 return ret;
1892         return gate_vma;
1893 }
1894 /*
1895  * Helper function for iterating across a vma list.  It ensures that the caller
1896  * will visit `gate_vma' prior to terminating the search.
1897  */
1898 static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
1899                                         struct vm_area_struct *gate_vma)
1900 {
1901         struct vm_area_struct *ret;
1902
1903         ret = this_vma->vm_next;
1904         if (ret)
1905                 return ret;
1906         if (this_vma == gate_vma)
1907                 return NULL;
1908         return gate_vma;
1909 }
1910
1911 /*
1912  * Actual dumper
1913  *
1914  * This is a two-pass process; first we find the offsets of the bits,
1915  * and then they are actually written out.  If we run out of core limit
1916  * we just truncate.
1917  */
1918 static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
1919 {
1920         int has_dumped = 0;
1921         mm_segment_t fs;
1922         int segs;
1923         size_t size = 0;
1924         struct vm_area_struct *vma, *gate_vma;
1925         struct elfhdr *elf = NULL;
1926         loff_t offset = 0, dataoff, foffset;
1927         unsigned long mm_flags;
1928         struct elf_note_info info;
1929
1930         /*
1931          * We no longer stop all VM operations.
1932          *
1933          * This is because those proceses that could possibly change map_count
1934          * or the mmap / vma pages are now blocked in do_exit on current
1935          * finishing this core dump.
1936          *
1937          * Only ptrace can touch these memory addresses, but it doesn't change
1938          * the map_count or the pages allocated. So no possibility of crashing
1939          * exists while dumping the mm->vm_next areas to the core file.
1940          */
1941
1942         /* alloc memory for large data structures: too large to be on stack */
1943         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1944         if (!elf)
1945                 goto out;
1946
1947         segs = current->mm->map_count;
1948 #ifdef ELF_CORE_EXTRA_PHDRS
1949         segs += ELF_CORE_EXTRA_PHDRS;
1950 #endif
1951
1952         gate_vma = get_gate_vma(current);
1953         if (gate_vma != NULL)
1954                 segs++;
1955
1956         /*
1957          * Collect all the non-memory information about the process for the
1958          * notes.  This also sets up the file header.
1959          */
1960         if (!fill_note_info(elf, segs + 1, /* including notes section */
1961                             &info, signr, regs))
1962                 goto cleanup;
1963
1964         has_dumped = 1;
1965         current->flags |= PF_DUMPCORE;
1966
1967         fs = get_fs();
1968         set_fs(KERNEL_DS);
1969
1970         DUMP_WRITE(elf, sizeof(*elf));
1971         offset += sizeof(*elf);                         /* Elf header */
1972         offset += (segs + 1) * sizeof(struct elf_phdr); /* Program headers */
1973         foffset = offset;
1974
1975         /* Write notes phdr entry */
1976         {
1977                 struct elf_phdr phdr;
1978                 size_t sz = get_note_info_size(&info);
1979
1980                 sz += elf_coredump_extra_notes_size();
1981
1982                 fill_elf_note_phdr(&phdr, sz, offset);
1983                 offset += sz;
1984                 DUMP_WRITE(&phdr, sizeof(phdr));
1985         }
1986
1987         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1988
1989         /*
1990          * We must use the same mm->flags while dumping core to avoid
1991          * inconsistency between the program headers and bodies, otherwise an
1992          * unusable core file can be generated.
1993          */
1994         mm_flags = current->mm->flags;
1995
1996         /* Write program headers for segments dump */
1997         for (vma = first_vma(current, gate_vma); vma != NULL;
1998                         vma = next_vma(vma, gate_vma)) {
1999                 struct elf_phdr phdr;
2000
2001                 phdr.p_type = PT_LOAD;
2002                 phdr.p_offset = offset;
2003                 phdr.p_vaddr = vma->vm_start;
2004                 phdr.p_paddr = 0;
2005                 phdr.p_filesz = vma_dump_size(vma, mm_flags);
2006                 phdr.p_memsz = vma->vm_end - vma->vm_start;
2007                 offset += phdr.p_filesz;
2008                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
2009                 if (vma->vm_flags & VM_WRITE)
2010                         phdr.p_flags |= PF_W;
2011                 if (vma->vm_flags & VM_EXEC)
2012                         phdr.p_flags |= PF_X;
2013                 phdr.p_align = ELF_EXEC_PAGESIZE;
2014
2015                 DUMP_WRITE(&phdr, sizeof(phdr));
2016         }
2017
2018 #ifdef ELF_CORE_WRITE_EXTRA_PHDRS
2019         ELF_CORE_WRITE_EXTRA_PHDRS;
2020 #endif
2021
2022         /* write out the notes section */
2023         if (!write_note_info(&info, file, &foffset))
2024                 goto end_coredump;
2025
2026         if (elf_coredump_extra_notes_write(file, &foffset))
2027                 goto end_coredump;
2028
2029         /* Align to page */
2030         DUMP_SEEK(dataoff - foffset);
2031
2032         for (vma = first_vma(current, gate_vma); vma != NULL;
2033                         vma = next_vma(vma, gate_vma)) {
2034                 unsigned long addr;
2035                 unsigned long end;
2036
2037                 end = vma->vm_start + vma_dump_size(vma, mm_flags);
2038
2039                 for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
2040                         struct page *page;
2041                         struct vm_area_struct *tmp_vma;
2042
2043                         if (get_user_pages(current, current->mm, addr, 1, 0, 1,
2044                                                 &page, &tmp_vma) <= 0) {
2045                                 DUMP_SEEK(PAGE_SIZE);
2046                         } else {
2047                                 if (page == ZERO_PAGE(0)) {
2048                                         if (!dump_seek(file, PAGE_SIZE)) {
2049                                                 page_cache_release(page);
2050                                                 goto end_coredump;
2051                                         }
2052                                 } else {
2053                                         void *kaddr;
2054                                         flush_cache_page(tmp_vma, addr,
2055                                                          page_to_pfn(page));
2056                                         kaddr = kmap(page);
2057                                         if ((size += PAGE_SIZE) > limit ||
2058                                             !dump_write(file, kaddr,
2059                                             PAGE_SIZE)) {
2060                                                 kunmap(page);
2061                                                 page_cache_release(page);
2062                                                 goto end_coredump;
2063                                         }
2064                                         kunmap(page);
2065                                 }
2066                                 page_cache_release(page);
2067                         }
2068                 }
2069         }
2070
2071 #ifdef ELF_CORE_WRITE_EXTRA_DATA
2072         ELF_CORE_WRITE_EXTRA_DATA;
2073 #endif
2074
2075 end_coredump:
2076         set_fs(fs);
2077
2078 cleanup:
2079         free_note_info(&info);
2080         kfree(elf);
2081 out:
2082         return has_dumped;
2083 }
2084
2085 #endif          /* USE_ELF_CORE_DUMP */
2086
2087 static int __init init_elf_binfmt(void)
2088 {
2089         return register_binfmt(&elf_format);
2090 }
2091
2092 static void __exit exit_elf_binfmt(void)
2093 {
2094         /* Remove the COFF and ELF loaders. */
2095         unregister_binfmt(&elf_format);
2096 }
2097
2098 core_initcall(init_elf_binfmt);
2099 module_exit(exit_elf_binfmt);
2100 MODULE_LICENSE("GPL");