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/mm.h>
  16 #include <linux/mman.h>
  17 #include <linux/errno.h>
  18 #include <linux/signal.h>
  19 #include <linux/binfmts.h>
  20 #include <linux/string.h>
  21 #include <linux/file.h>
  22 #include <linux/slab.h>
  23 #include <linux/personality.h>
  24 #include <linux/elfcore.h>
  25 #include <linux/init.h>
  26 #include <linux/highuid.h>
  27 #include <linux/compiler.h>
  28 #include <linux/highmem.h>
  29 #include <linux/pagemap.h>
  30 #include <linux/security.h>
  31 #include <linux/random.h>
  32 #include <linux/elf.h>
  33 #include <linux/utsname.h>
  34 #include <linux/coredump.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/param.h>
  37 #include <asm/page.h>
  38
  39 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
  40 static int load_elf_library(struct file *);
  41 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
  42                                 int, int, unsigned long);
  43
  44 /*
  45  * If we don't support core dumping, then supply a NULL so we
  46  * don't even try.
  47  */
  48 #ifdef CONFIG_ELF_CORE
  49 static int elf_core_dump(struct coredump_params *cprm);
  50 #else
  51 #define elf_core_dump   NULL
  52 #endif
  53
  54 #if ELF_EXEC_PAGESIZE > PAGE_SIZE
  55 #define ELF_MIN_ALIGN   ELF_EXEC_PAGESIZE
  56 #else
  57 #define ELF_MIN_ALIGN   PAGE_SIZE
  58 #endif
  59
  60 #ifndef ELF_CORE_EFLAGS
  61 #define ELF_CORE_EFLAGS 0
  62 #endif
  63
  64 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
  65 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
  66 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
  67
  68 static struct linux_binfmt elf_format = {
  69         .module         = THIS_MODULE,
  70         .load_binary    = load_elf_binary,
  71         .load_shlib     = load_elf_library,
  72         .core_dump      = elf_core_dump,
  73         .min_coredump   = ELF_EXEC_PAGESIZE,
  74 };
  75
  76 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
  77
  78 static int set_brk(unsigned long start, unsigned long end)
  79 {
  80         start = ELF_PAGEALIGN(start);
  81         end = ELF_PAGEALIGN(end);
  82         if (end > start) {
  83                 unsigned long addr;
  84                 down_write(&current->mm->mmap_sem);
  85                 addr = do_brk(start, end - start);
  86                 up_write(&current->mm->mmap_sem);
  87                 if (BAD_ADDR(addr))
  88                         return addr;
  89         }
  90         current->mm->start_brk = current->mm->brk = end;
  91         return 0;
  92 }
  93
  94 /* We need to explicitly zero any fractional pages
  95    after the data section (i.e. bss).  This would
  96    contain the junk from the file that should not
  97    be in memory
  98  */
  99 static int padzero(unsigned long elf_bss)
 100 {
 101         unsigned long nbyte;
 102
 103         nbyte = ELF_PAGEOFFSET(elf_bss);
 104         if (nbyte) {
 105                 nbyte = ELF_MIN_ALIGN - nbyte;
 106                 if (clear_user((void __user *) elf_bss, nbyte))
 107                         return -EFAULT;
 108         }
 109         return 0;
 110 }
 111
 112 /* Let's use some macros to make this stack manipulation a little clearer */
 113 #ifdef CONFIG_STACK_GROWSUP
 114 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
 115 #define STACK_ROUND(sp, items) \
 116         ((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
 117 #define STACK_ALLOC(sp, len) ({ \
 118         elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
 119         old_sp; })
 120 #else
 121 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
 122 #define STACK_ROUND(sp, items) \
 123         (((unsigned long) (sp - items)) &~ 15UL)
 124 #define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
 125 #endif
 126
 127 #ifndef ELF_BASE_PLATFORM
 128 /*
 129  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 130  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 131  * will be copied to the user stack in the same manner as AT_PLATFORM.
 132  */
 133 #define ELF_BASE_PLATFORM NULL
 134 #endif
 135
 136 static int
 137 create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
 138                 unsigned long load_addr, unsigned long interp_load_addr)
 139 {
 140         unsigned long p = bprm->p;
 141         int argc = bprm->argc;
 142         int envc = bprm->envc;
 143         elf_addr_t __user *argv;
 144         elf_addr_t __user *envp;
 145         elf_addr_t __user *sp;
 146         elf_addr_t __user *u_platform;
 147         elf_addr_t __user *u_base_platform;
 148         elf_addr_t __user *u_rand_bytes;
 149         const char *k_platform = ELF_PLATFORM;
 150         const char *k_base_platform = ELF_BASE_PLATFORM;
 151         unsigned char k_rand_bytes[16];
 152         int items;
 153         elf_addr_t *elf_info;
 154         int ei_index = 0;
 155         const struct cred *cred = current_cred();
 156         struct vm_area_struct *vma;
 157
 158         /*
 159          * In some cases (e.g. Hyper-Threading), we want to avoid L1
 160          * evictions by the processes running on the same package. One
 161          * thing we can do is to shuffle the initial stack for them.
 162          */
 163
 164         p = arch_align_stack(p);
 165
 166         /*
 167          * If this architecture has a platform capability string, copy it
 168          * to userspace.  In some cases (Sparc), this info is impossible
 169          * for userspace to get any other way, in others (i386) it is
 170          * merely difficult.
 171          */
 172         u_platform = NULL;
 173         if (k_platform) {
 174                 size_t len = strlen(k_platform) + 1;
 175
 176                 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 177                 if (__copy_to_user(u_platform, k_platform, len))
 178                         return -EFAULT;
 179         }
 180
 181         /*
 182          * If this architecture has a "base" platform capability
 183          * string, copy it to userspace.
 184          */
 185         u_base_platform = NULL;
 186         if (k_base_platform) {
 187                 size_t len = strlen(k_base_platform) + 1;
 188
 189                 u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 190                 if (__copy_to_user(u_base_platform, k_base_platform, len))
 191                         return -EFAULT;
 192         }
 193
 194         /*
 195          * Generate 16 random bytes for userspace PRNG seeding.
 196          */
 197         get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
 198         u_rand_bytes = (elf_addr_t __user *)
 199                        STACK_ALLOC(p, sizeof(k_rand_bytes));
 200         if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
 201                 return -EFAULT;
 202
 203         /* Create the ELF interpreter info */
 204         elf_info = (elf_addr_t *)current->mm->saved_auxv;
 205         /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
 206 #define NEW_AUX_ENT(id, val) \
 207         do { \
 208                 elf_info[ei_index++] = id; \
 209                 elf_info[ei_index++] = val; \
 210         } while (0)
 211
 212 #ifdef ARCH_DLINFO
 213         /*
 214          * ARCH_DLINFO must come first so PPC can do its special alignment of
 215          * AUXV.
 216          * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
 217          * ARCH_DLINFO changes
 218          */
 219         ARCH_DLINFO;
 220 #endif
 221         NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
 222         NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
 223         NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
 224         NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
 225         NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
 226         NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
 227         NEW_AUX_ENT(AT_BASE, interp_load_addr);
 228         NEW_AUX_ENT(AT_FLAGS, 0);
 229         NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
 230         NEW_AUX_ENT(AT_UID, cred->uid);
 231         NEW_AUX_ENT(AT_EUID, cred->euid);
 232         NEW_AUX_ENT(AT_GID, cred->gid);
 233         NEW_AUX_ENT(AT_EGID, cred->egid);
 234         NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
 235         NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
 236         NEW_AUX_ENT(AT_EXECFN, bprm->exec);
 237         if (k_platform) {
 238                 NEW_AUX_ENT(AT_PLATFORM,
 239                             (elf_addr_t)(unsigned long)u_platform);
 240         }
 241         if (k_base_platform) {
 242                 NEW_AUX_ENT(AT_BASE_PLATFORM,
 243                             (elf_addr_t)(unsigned long)u_base_platform);
 244         }
 245         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
 246                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
 247         }
 248 #undef NEW_AUX_ENT
 249         /* AT_NULL is zero; clear the rest too */
 250         memset(&elf_info[ei_index], 0,
 251                sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
 252
 253         /* And advance past the AT_NULL entry.  */
 254         ei_index += 2;
 255
 256         sp = STACK_ADD(p, ei_index);
 257
 258         items = (argc + 1) + (envc + 1) + 1;
 259         bprm->p = STACK_ROUND(sp, items);
 260
 261         /* Point sp at the lowest address on the stack */
 262 #ifdef CONFIG_STACK_GROWSUP
 263         sp = (elf_addr_t __user *)bprm->p - items - ei_index;
 264         bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
 265 #else
 266         sp = (elf_addr_t __user *)bprm->p;
 267 #endif
 268
 269
 270         /*
 271          * Grow the stack manually; some architectures have a limit on how
 272          * far ahead a user-space access may be in order to grow the stack.
 273          */
 274         vma = find_extend_vma(current->mm, bprm->p);
 275         if (!vma)
 276                 return -EFAULT;
 277
 278         /* Now, let's put argc (and argv, envp if appropriate) on the stack */
 279         if (__put_user(argc, sp++))
 280                 return -EFAULT;
 281         argv = sp;
 282         envp = argv + argc + 1;
 283
 284         /* Populate argv and envp */
 285         p = current->mm->arg_end = current->mm->arg_start;
 286         while (argc-- > 0) {
 287                 size_t len;
 288                 if (__put_user((elf_addr_t)p, argv++))
 289                         return -EFAULT;
 290                 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
 291                 if (!len || len > MAX_ARG_STRLEN)
 292                         return -EINVAL;
 293                 p += len;
 294         }
 295         if (__put_user(0, argv))
 296                 return -EFAULT;
 297         current->mm->arg_end = current->mm->env_start = p;
 298         while (envc-- > 0) {
 299                 size_t len;
 300                 if (__put_user((elf_addr_t)p, envp++))
 301                         return -EFAULT;
 302                 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
 303                 if (!len || len > MAX_ARG_STRLEN)
 304                         return -EINVAL;
 305                 p += len;
 306         }
 307         if (__put_user(0, envp))
 308                 return -EFAULT;
 309         current->mm->env_end = p;
 310
 311         /* Put the elf_info on the stack in the right place.  */
 312         sp = (elf_addr_t __user *)envp + 1;
 313         if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
 314                 return -EFAULT;
 315         return 0;
 316 }
 317
 318 static unsigned long elf_map(struct file *filep, unsigned long addr,
 319                 struct elf_phdr *eppnt, int prot, int type,
 320                 unsigned long total_size)
 321 {
 322         unsigned long map_addr;
 323         unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
 324         unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
 325         addr = ELF_PAGESTART(addr);
 326         size = ELF_PAGEALIGN(size);
 327
 328         /* mmap() will return -EINVAL if given a zero size, but a
 329          * segment with zero filesize is perfectly valid */
 330         if (!size)
 331                 return addr;
 332
 333         down_write(&current->mm->mmap_sem);
 334         /*
 335         * total_size is the size of the ELF (interpreter) image.
 336         * The _first_ mmap needs to know the full size, otherwise
 337         * randomization might put this image into an overlapping
 338         * position with the ELF binary image. (since size < total_size)
 339         * So we first map the 'big' image - and unmap the remainder at
 340         * the end. (which unmap is needed for ELF images with holes.)
 341         */
 342         if (total_size) {
 343                 total_size = ELF_PAGEALIGN(total_size);
 344                 map_addr = do_mmap(filep, addr, total_size, prot, type, off);
 345                 if (!BAD_ADDR(map_addr))
 346                         do_munmap(current->mm, map_addr+size, total_size-size);
 347         } else
 348                 map_addr = do_mmap(filep, addr, size, prot, type, off);
 349
 350         up_write(&current->mm->mmap_sem);
 351         return(map_addr);
 352 }
 353
 354 static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
 355 {
 356         int i, first_idx = -1, last_idx = -1;
 357
 358         for (i = 0; i < nr; i++) {
 359                 if (cmds[i].p_type == PT_LOAD) {
 360                         last_idx = i;
 361                         if (first_idx == -1)
 362                                 first_idx = i;
 363                 }
 364         }
 365         if (first_idx == -1)
 366                 return 0;
 367
 368         return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
 369                                 ELF_PAGESTART(cmds[first_idx].p_vaddr);
 370 }
 371
 372
 373 /* This is much more generalized than the library routine read function,
 374    so we keep this separate.  Technically the library read function
 375    is only provided so that we can read a.out libraries that have
 376    an ELF header */
 377
 378 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 379                 struct file *interpreter, unsigned long *interp_map_addr,
 380                 unsigned long no_base)
 381 {
 382         struct elf_phdr *elf_phdata;
 383         struct elf_phdr *eppnt;
 384         unsigned long load_addr = 0;
 385         int load_addr_set = 0;
 386         unsigned long last_bss = 0, elf_bss = 0;
 387         unsigned long error = ~0UL;
 388         unsigned long total_size;
 389         int retval, i, size;
 390
 391         /* First of all, some simple consistency checks */
 392         if (interp_elf_ex->e_type != ET_EXEC &&
 393             interp_elf_ex->e_type != ET_DYN)
 394                 goto out;
 395         if (!elf_check_arch(interp_elf_ex))
 396                 goto out;
 397         if (!interpreter->f_op || !interpreter->f_op->mmap)
 398                 goto out;
 399
 400         /*
 401          * If the size of this structure has changed, then punt, since
 402          * we will be doing the wrong thing.
 403          */
 404         if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
 405                 goto out;
 406         if (interp_elf_ex->e_phnum < 1 ||
 407                 interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
 408                 goto out;
 409
 410         /* Now read in all of the header information */
 411         size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
 412         if (size > ELF_MIN_ALIGN)
 413                 goto out;
 414         elf_phdata = kmalloc(size, GFP_KERNEL);
 415         if (!elf_phdata)
 416                 goto out;
 417
 418         retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
 419                              (char *)elf_phdata, size);
 420         error = -EIO;
 421         if (retval != size) {
 422                 if (retval < 0)
 423                         error = retval;
 424                 goto out_close;
 425         }
 426
 427         total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
 428         if (!total_size) {
 429                 error = -EINVAL;
 430                 goto out_close;
 431         }
 432
 433         eppnt = elf_phdata;
 434         for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
 435                 if (eppnt->p_type == PT_LOAD) {
 436                         int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
 437                         int elf_prot = 0;
 438                         unsigned long vaddr = 0;
 439                         unsigned long k, map_addr;
 440
 441                         if (eppnt->p_flags & PF_R)
 442                                 elf_prot = PROT_READ;
 443                         if (eppnt->p_flags & PF_W)
 444                                 elf_prot |= PROT_WRITE;
 445                         if (eppnt->p_flags & PF_X)
 446                                 elf_prot |= PROT_EXEC;
 447                         vaddr = eppnt->p_vaddr;
 448                         if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
 449                                 elf_type |= MAP_FIXED;
 450                         else if (no_base && interp_elf_ex->e_type == ET_DYN)
 451                                 load_addr = -vaddr;
 452
 453                         map_addr = elf_map(interpreter, load_addr + vaddr,
 454                                         eppnt, elf_prot, elf_type, total_size);
 455                         total_size = 0;
 456                         if (!*interp_map_addr)
 457                                 *interp_map_addr = map_addr;
 458                         error = map_addr;
 459                         if (BAD_ADDR(map_addr))
 460                                 goto out_close;
 461
 462                         if (!load_addr_set &&
 463                             interp_elf_ex->e_type == ET_DYN) {
 464                                 load_addr = map_addr - ELF_PAGESTART(vaddr);
 465                                 load_addr_set = 1;
 466                         }
 467
 468                         /*
 469                          * Check to see if the section's size will overflow the
 470                          * allowed task size. Note that p_filesz must always be
 471                          * <= p_memsize so it's only necessary to check p_memsz.
 472                          */
 473                         k = load_addr + eppnt->p_vaddr;
 474                         if (BAD_ADDR(k) ||
 475                             eppnt->p_filesz > eppnt->p_memsz ||
 476                             eppnt->p_memsz > TASK_SIZE ||
 477                             TASK_SIZE - eppnt->p_memsz < k) {
 478                                 error = -ENOMEM;
 479                                 goto out_close;
 480                         }
 481
 482                         /*
 483                          * Find the end of the file mapping for this phdr, and
 484                          * keep track of the largest address we see for this.
 485                          */
 486                         k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
 487                         if (k > elf_bss)
 488                                 elf_bss = k;
 489
 490                         /*
 491                          * Do the same thing for the memory mapping - between
 492                          * elf_bss and last_bss is the bss section.
 493                          */
 494                         k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
 495                         if (k > last_bss)
 496                                 last_bss = k;
 497                 }
 498         }
 499
 500         if (last_bss > elf_bss) {
 501                 /*
 502                  * Now fill out the bss section.  First pad the last page up
 503                  * to the page boundary, and then perform a mmap to make sure
 504                  * that there are zero-mapped pages up to and including the
 505                  * last bss page.
 506                  */
 507                 if (padzero(elf_bss)) {
 508                         error = -EFAULT;
 509                         goto out_close;
 510                 }
 511
 512                 /* What we have mapped so far */
 513                 elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
 514
 515                 /* Map the last of the bss segment */
 516                 down_write(&current->mm->mmap_sem);
 517                 error = do_brk(elf_bss, last_bss - elf_bss);
 518                 up_write(&current->mm->mmap_sem);
 519                 if (BAD_ADDR(error))
 520                         goto out_close;
 521         }
 522
 523         error = load_addr;
 524
 525 out_close:
 526         kfree(elf_phdata);
 527 out:
 528         return error;
 529 }
 530
 531 /*
 532  * These are the functions used to load ELF style executables and shared
 533  * libraries.  There is no binary dependent code anywhere else.
 534  */
 535
 536 #define INTERPRETER_NONE 0
 537 #define INTERPRETER_ELF 2
 538
 539 #ifndef STACK_RND_MASK
 540 #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))     /* 8MB of VA */
 541 #endif
 542
 543 static unsigned long randomize_stack_top(unsigned long stack_top)
 544 {
 545         unsigned int random_variable = 0;
 546
 547         if ((current->flags & PF_RANDOMIZE) &&
 548                 !(current->personality & ADDR_NO_RANDOMIZE)) {
 549                 random_variable = get_random_int() & STACK_RND_MASK;
 550                 random_variable <<= PAGE_SHIFT;
 551         }
 552 #ifdef CONFIG_STACK_GROWSUP
 553         return PAGE_ALIGN(stack_top) + random_variable;
 554 #else
 555         return PAGE_ALIGN(stack_top) - random_variable;
 556 #endif
 557 }
 558
 559 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 560 {
 561         struct file *interpreter = NULL; /* to shut gcc up */
 562         unsigned long load_addr = 0, load_bias = 0;
 563         int load_addr_set = 0;
 564         char * elf_interpreter = NULL;
 565         unsigned long error;
 566         struct elf_phdr *elf_ppnt, *elf_phdata;
 567         unsigned long elf_bss, elf_brk;
 568         int retval, i;
 569         unsigned int size;
 570         unsigned long elf_entry;
 571         unsigned long interp_load_addr = 0;
 572         unsigned long start_code, end_code, start_data, end_data;
 573         unsigned long reloc_func_desc = 0;
 574         int executable_stack = EXSTACK_DEFAULT;
 575         unsigned long def_flags = 0;
 576         struct {
 577                 struct elfhdr elf_ex;
 578                 struct elfhdr interp_elf_ex;
 579         } *loc;
 580
 581         loc = kmalloc(sizeof(*loc), GFP_KERNEL);
 582         if (!loc) {
 583                 retval = -ENOMEM;
 584                 goto out_ret;
 585         }
 586
 587         /* Get the exec-header */
 588         loc->elf_ex = *((struct elfhdr *)bprm->buf);
 589
 590         retval = -ENOEXEC;
 591         /* First of all, some simple consistency checks */
 592         if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 593                 goto out;
 594
 595         if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
 596                 goto out;
 597         if (!elf_check_arch(&loc->elf_ex))
 598                 goto out;
 599         if (!bprm->file->f_op || !bprm->file->f_op->mmap)
 600                 goto out;
 601
 602         /* Now read in all of the header information */
 603         if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
 604                 goto out;
 605         if (loc->elf_ex.e_phnum < 1 ||
 606                 loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
 607                 goto out;
 608         size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
 609         retval = -ENOMEM;
 610         elf_phdata = kmalloc(size, GFP_KERNEL);
 611         if (!elf_phdata)
 612                 goto out;
 613
 614         retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
 615                              (char *)elf_phdata, size);
 616         if (retval != size) {
 617                 if (retval >= 0)
 618                         retval = -EIO;
 619                 goto out_free_ph;
 620         }
 621
 622         elf_ppnt = elf_phdata;
 623         elf_bss = 0;
 624         elf_brk = 0;
 625
 626         start_code = ~0UL;
 627         end_code = 0;
 628         start_data = 0;
 629         end_data = 0;
 630
 631         for (i = 0; i < loc->elf_ex.e_phnum; i++) {
 632                 if (elf_ppnt->p_type == PT_INTERP) {
 633                         /* This is the program interpreter used for
 634                          * shared libraries - for now assume that this
 635                          * is an a.out format binary
 636                          */
 637                         retval = -ENOEXEC;
 638                         if (elf_ppnt->p_filesz > PATH_MAX ||
 639                             elf_ppnt->p_filesz < 2)
 640                                 goto out_free_ph;
 641
 642                         retval = -ENOMEM;
 643                         elf_interpreter = kmalloc(elf_ppnt->p_filesz,
 644                                                   GFP_KERNEL);
 645                         if (!elf_interpreter)
 646                                 goto out_free_ph;
 647
 648                         retval = kernel_read(bprm->file, elf_ppnt->p_offset,
 649                                              elf_interpreter,
 650                                              elf_ppnt->p_filesz);
 651                         if (retval != elf_ppnt->p_filesz) {
 652                                 if (retval >= 0)
 653                                         retval = -EIO;
 654                                 goto out_free_interp;
 655                         }
 656                         /* make sure path is NULL terminated */
 657                         retval = -ENOEXEC;
 658                         if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
 659                                 goto out_free_interp;
 660
 661                         interpreter = open_exec(elf_interpreter);
 662                         retval = PTR_ERR(interpreter);
 663                         if (IS_ERR(interpreter))
 664                                 goto out_free_interp;
 665
 666                         /*
 667                          * If the binary is not readable then enforce
 668                          * mm->dumpable = 0 regardless of the interpreter's
 669                          * permissions.
 670                          */
 671                         if (file_permission(interpreter, MAY_READ) < 0)
 672                                 bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
 673
 674                         retval = kernel_read(interpreter, 0, bprm->buf,
 675                                              BINPRM_BUF_SIZE);
 676                         if (retval != BINPRM_BUF_SIZE) {
 677                                 if (retval >= 0)
 678                                         retval = -EIO;
 679                                 goto out_free_dentry;
 680                         }
 681
 682                         /* Get the exec headers */
 683                         loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
 684                         break;
 685                 }
 686                 elf_ppnt++;
 687         }
 688
 689         elf_ppnt = elf_phdata;
 690         for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
 691                 if (elf_ppnt->p_type == PT_GNU_STACK) {
 692                         if (elf_ppnt->p_flags & PF_X)
 693                                 executable_stack = EXSTACK_ENABLE_X;
 694                         else
 695                                 executable_stack = EXSTACK_DISABLE_X;
 696                         break;
 697                 }
 698
 699         /* Some simple consistency checks for the interpreter */
 700         if (elf_interpreter) {
 701                 retval = -ELIBBAD;
 702                 /* Not an ELF interpreter */
 703                 if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 704                         goto out_free_dentry;
 705                 /* Verify the interpreter has a valid arch */
 706                 if (!elf_check_arch(&loc->interp_elf_ex))
 707                         goto out_free_dentry;
 708         }
 709
 710         /* Flush all traces of the currently running executable */
 711         retval = flush_old_exec(bprm);
 712         if (retval)
 713                 goto out_free_dentry;
 714
 715         /* OK, This is the point of no return */
 716         current->flags &= ~PF_FORKNOEXEC;
 717         current->mm->def_flags = def_flags;
 718
 719         /* Do this immediately, since STACK_TOP as used in setup_arg_pages
 720            may depend on the personality.  */
 721         SET_PERSONALITY(loc->elf_ex);
 722         if (elf_read_implies_exec(loc->elf_ex, executable_stack))
 723                 current->personality |= READ_IMPLIES_EXEC;
 724
 725         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 726                 current->flags |= PF_RANDOMIZE;
 727
 728         setup_new_exec(bprm);
 729
 730         /* Do this so that we can load the interpreter, if need be.  We will
 731            change some of these later */
 732         current->mm->free_area_cache = current->mm->mmap_base;
 733         current->mm->cached_hole_size = 0;
 734         retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
 735                                  executable_stack);
 736         if (retval < 0) {
 737                 send_sig(SIGKILL, current, 0);
 738                 goto out_free_dentry;
 739         }
 740
 741         current->mm->start_stack = bprm->p;
 742
 743         /* Now we do a little grungy work by mmapping the ELF image into
 744            the correct location in memory. */
 745         for(i = 0, elf_ppnt = elf_phdata;
 746             i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
 747                 int elf_prot = 0, elf_flags;
 748                 unsigned long k, vaddr;
 749
 750                 if (elf_ppnt->p_type != PT_LOAD)
 751                         continue;
 752
 753                 if (unlikely (elf_brk > elf_bss)) {
 754                         unsigned long nbyte;
 755
 756                         /* There was a PT_LOAD segment with p_memsz > p_filesz
 757                            before this one. Map anonymous pages, if needed,
 758                            and clear the area.  */
 759                         retval = set_brk(elf_bss + load_bias,
 760                                          elf_brk + load_bias);
 761                         if (retval) {
 762                                 send_sig(SIGKILL, current, 0);
 763                                 goto out_free_dentry;
 764                         }
 765                         nbyte = ELF_PAGEOFFSET(elf_bss);
 766                         if (nbyte) {
 767                                 nbyte = ELF_MIN_ALIGN - nbyte;
 768                                 if (nbyte > elf_brk - elf_bss)
 769                                         nbyte = elf_brk - elf_bss;
 770                                 if (clear_user((void __user *)elf_bss +
 771                                                         load_bias, nbyte)) {
 772                                         /*
 773                                          * This bss-zeroing can fail if the ELF
 774                                          * file specifies odd protections. So
 775                                          * we don't check the return value
 776                                          */
 777                                 }
 778                         }
 779                 }
 780
 781                 if (elf_ppnt->p_flags & PF_R)
 782                         elf_prot |= PROT_READ;
 783                 if (elf_ppnt->p_flags & PF_W)
 784                         elf_prot |= PROT_WRITE;
 785                 if (elf_ppnt->p_flags & PF_X)
 786                         elf_prot |= PROT_EXEC;
 787
 788                 elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
 789
 790                 vaddr = elf_ppnt->p_vaddr;
 791                 if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
 792                         elf_flags |= MAP_FIXED;
 793                 } else if (loc->elf_ex.e_type == ET_DYN) {
 794                         /* Try and get dynamic programs out of the way of the
 795                          * default mmap base, as well as whatever program they
 796                          * might try to exec.  This is because the brk will
 797                          * follow the loader, and is not movable.  */
 798 #if defined(CONFIG_X86) || defined(CONFIG_ARM)
 799                         load_bias = 0;
 800 #else
 801                         load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
 802 #endif
 803                 }
 804
 805                 error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
 806                                 elf_prot, elf_flags, 0);
 807                 if (BAD_ADDR(error)) {
 808                         send_sig(SIGKILL, current, 0);
 809                         retval = IS_ERR((void *)error) ?
 810                                 PTR_ERR((void*)error) : -EINVAL;
 811                         goto out_free_dentry;
 812                 }
 813
 814                 if (!load_addr_set) {
 815                         load_addr_set = 1;
 816                         load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
 817                         if (loc->elf_ex.e_type == ET_DYN) {
 818                                 load_bias += error -
 819                                              ELF_PAGESTART(load_bias + vaddr);
 820                                 load_addr += load_bias;
 821                                 reloc_func_desc = load_bias;
 822                         }
 823                 }
 824                 k = elf_ppnt->p_vaddr;
 825                 if (k < start_code)
 826                         start_code = k;
 827                 if (start_data < k)
 828                         start_data = k;
 829
 830                 /*
 831                  * Check to see if the section's size will overflow the
 832                  * allowed task size. Note that p_filesz must always be
 833                  * <= p_memsz so it is only necessary to check p_memsz.
 834                  */
 835                 if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
 836                     elf_ppnt->p_memsz > TASK_SIZE ||
 837                     TASK_SIZE - elf_ppnt->p_memsz < k) {
 838                         /* set_brk can never work. Avoid overflows. */
 839                         send_sig(SIGKILL, current, 0);
 840                         retval = -EINVAL;
 841                         goto out_free_dentry;
 842                 }
 843
 844                 k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
 845
 846                 if (k > elf_bss)
 847                         elf_bss = k;
 848                 if ((elf_ppnt->p_flags & PF_X) && end_code < k)
 849                         end_code = k;
 850                 if (end_data < k)
 851                         end_data = k;
 852                 k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
 853                 if (k > elf_brk)
 854                         elf_brk = k;
 855         }
 856
 857         loc->elf_ex.e_entry += load_bias;
 858         elf_bss += load_bias;
 859         elf_brk += load_bias;
 860         start_code += load_bias;
 861         end_code += load_bias;
 862         start_data += load_bias;
 863         end_data += load_bias;
 864
 865         /* Calling set_brk effectively mmaps the pages that we need
 866          * for the bss and break sections.  We must do this before
 867          * mapping in the interpreter, to make sure it doesn't wind
 868          * up getting placed where the bss needs to go.
 869          */
 870         retval = set_brk(elf_bss, elf_brk);
 871         if (retval) {
 872                 send_sig(SIGKILL, current, 0);
 873                 goto out_free_dentry;
 874         }
 875         if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
 876                 send_sig(SIGSEGV, current, 0);
 877                 retval = -EFAULT; /* Nobody gets to see this, but.. */
 878                 goto out_free_dentry;
 879         }
 880
 881         if (elf_interpreter) {
 882                 unsigned long uninitialized_var(interp_map_addr);
 883
 884                 elf_entry = load_elf_interp(&loc->interp_elf_ex,
 885                                             interpreter,
 886                                             &interp_map_addr,
 887                                             load_bias);
 888                 if (!IS_ERR((void *)elf_entry)) {
 889                         /*
 890                          * load_elf_interp() returns relocation
 891                          * adjustment
 892                          */
 893                         interp_load_addr = elf_entry;
 894                         elf_entry += loc->interp_elf_ex.e_entry;
 895                 }
 896                 if (BAD_ADDR(elf_entry)) {
 897                         force_sig(SIGSEGV, current);
 898                         retval = IS_ERR((void *)elf_entry) ?
 899                                         (int)elf_entry : -EINVAL;
 900                         goto out_free_dentry;
 901                 }
 902                 reloc_func_desc = interp_load_addr;
 903
 904                 allow_write_access(interpreter);
 905                 fput(interpreter);
 906                 kfree(elf_interpreter);
 907         } else {
 908                 elf_entry = loc->elf_ex.e_entry;
 909                 if (BAD_ADDR(elf_entry)) {
 910                         force_sig(SIGSEGV, current);
 911                         retval = -EINVAL;
 912                         goto out_free_dentry;
 913                 }
 914         }
 915
 916         kfree(elf_phdata);
 917
 918         set_binfmt(&elf_format);
 919
 920 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 921         retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
 922         if (retval < 0) {
 923                 send_sig(SIGKILL, current, 0);
 924                 goto out;
 925         }
 926 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 927
 928         install_exec_creds(bprm);
 929         current->flags &= ~PF_FORKNOEXEC;
 930         retval = create_elf_tables(bprm, &loc->elf_ex,
 931                           load_addr, interp_load_addr);
 932         if (retval < 0) {
 933                 send_sig(SIGKILL, current, 0);
 934                 goto out;
 935         }
 936         /* N.B. passed_fileno might not be initialized? */
 937         current->mm->end_code = end_code;
 938         current->mm->start_code = start_code;
 939         current->mm->start_data = start_data;
 940         current->mm->end_data = end_data;
 941         current->mm->start_stack = bprm->p;
 942
 943 #ifdef arch_randomize_brk
 944         if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1))
 945                 current->mm->brk = current->mm->start_brk =
 946                         arch_randomize_brk(current->mm);
 947 #endif
 948
 949         if (current->personality & MMAP_PAGE_ZERO) {
 950                 /* Why this, you ask???  Well SVr4 maps page 0 as read-only,
 951                    and some applications "depend" upon this behavior.
 952                    Since we do not have the power to recompile these, we
 953                    emulate the SVr4 behavior. Sigh. */
 954                 down_write(&current->mm->mmap_sem);
 955                 error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
 956                                 MAP_FIXED | MAP_PRIVATE, 0);
 957                 up_write(&current->mm->mmap_sem);
 958         }
 959
 960 #ifdef ELF_PLAT_INIT
 961         /*
 962          * The ABI may specify that certain registers be set up in special
 963          * ways (on i386 %edx is the address of a DT_FINI function, for
 964          * example.  In addition, it may also specify (eg, PowerPC64 ELF)
 965          * that the e_entry field is the address of the function descriptor
 966          * for the startup routine, rather than the address of the startup
 967          * routine itself.  This macro performs whatever initialization to
 968          * the regs structure is required as well as any relocations to the
 969          * function descriptor entries when executing dynamically links apps.
 970          */
 971         ELF_PLAT_INIT(regs, reloc_func_desc);
 972 #endif
 973
 974         start_thread(regs, elf_entry, bprm->p);
 975         retval = 0;
 976 out:
 977         kfree(loc);
 978 out_ret:
 979         return retval;
 980
 981         /* error cleanup */
 982 out_free_dentry:
 983         allow_write_access(interpreter);
 984         if (interpreter)
 985                 fput(interpreter);
 986 out_free_interp:
 987         kfree(elf_interpreter);
 988 out_free_ph:
 989         kfree(elf_phdata);
 990         goto out;
 991 }
 992
 993 /* This is really simpleminded and specialized - we are loading an
 994    a.out library that is given an ELF header. */
 995 static int load_elf_library(struct file *file)
 996 {
 997         struct elf_phdr *elf_phdata;
 998         struct elf_phdr *eppnt;
 999         unsigned long elf_bss, bss, len;
1000         int retval, error, i, j;
1001         struct elfhdr elf_ex;
1002
1003         error = -ENOEXEC;
1004         retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
1005         if (retval != sizeof(elf_ex))
1006                 goto out;
1007
1008         if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1009                 goto out;
1010
1011         /* First of all, some simple consistency checks */
1012         if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1013             !elf_check_arch(&elf_ex) || !file->f_op || !file->f_op->mmap)
1014                 goto out;
1015
1016         /* Now read in all of the header information */
1017
1018         j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1019         /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1020
1021         error = -ENOMEM;
1022         elf_phdata = kmalloc(j, GFP_KERNEL);
1023         if (!elf_phdata)
1024                 goto out;
1025
1026         eppnt = elf_phdata;
1027         error = -ENOEXEC;
1028         retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
1029         if (retval != j)
1030                 goto out_free_ph;
1031
1032         for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1033                 if ((eppnt + i)->p_type == PT_LOAD)
1034                         j++;
1035         if (j != 1)
1036                 goto out_free_ph;
1037
1038         while (eppnt->p_type != PT_LOAD)
1039                 eppnt++;
1040
1041         /* Now use mmap to map the library into memory. */
1042         down_write(&current->mm->mmap_sem);
1043         error = do_mmap(file,
1044                         ELF_PAGESTART(eppnt->p_vaddr),
1045                         (eppnt->p_filesz +
1046                          ELF_PAGEOFFSET(eppnt->p_vaddr)),
1047                         PROT_READ | PROT_WRITE | PROT_EXEC,
1048                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
1049                         (eppnt->p_offset -
1050                          ELF_PAGEOFFSET(eppnt->p_vaddr)));
1051         up_write(&current->mm->mmap_sem);
1052         if (error != ELF_PAGESTART(eppnt->p_vaddr))
1053                 goto out_free_ph;
1054
1055         elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
1056         if (padzero(elf_bss)) {
1057                 error = -EFAULT;
1058                 goto out_free_ph;
1059         }
1060
1061         len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
1062                             ELF_MIN_ALIGN - 1);
1063         bss = eppnt->p_memsz + eppnt->p_vaddr;
1064         if (bss > len) {
1065                 down_write(&current->mm->mmap_sem);
1066                 do_brk(len, bss - len);
1067                 up_write(&current->mm->mmap_sem);
1068         }
1069         error = 0;
1070
1071 out_free_ph:
1072         kfree(elf_phdata);
1073 out:
1074         return error;
1075 }
1076
1077 #ifdef CONFIG_ELF_CORE
1078 /*
1079  * ELF core dumper
1080  *
1081  * Modelled on fs/exec.c:aout_core_dump()
1082  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1083  */
1084
1085 /*
1086  * Decide what to dump of a segment, part, all or none.
1087  */
1088 static unsigned long vma_dump_size(struct vm_area_struct *vma,
1089                                    unsigned long mm_flags)
1090 {
1091 #define FILTER(type)    (mm_flags & (1UL << MMF_DUMP_##type))
1092
1093         /* The vma can be set up to tell us the answer directly.  */
1094         if (vma->vm_flags & VM_ALWAYSDUMP)
1095                 goto whole;
1096
1097         /* Hugetlb memory check */
1098         if (vma->vm_flags & VM_HUGETLB) {
1099                 if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
1100                         goto whole;
1101                 if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
1102                         goto whole;
1103         }
1104
1105         /* Do not dump I/O mapped devices or special mappings */
1106         if (vma->vm_flags & (VM_IO | VM_RESERVED))
1107                 return 0;
1108
1109         /* By default, dump shared memory if mapped from an anonymous file. */
1110         if (vma->vm_flags & VM_SHARED) {
1111                 if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ?
1112                     FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
1113                         goto whole;
1114                 return 0;
1115         }
1116
1117         /* Dump segments that have been written to.  */
1118         if (vma->anon_vma && FILTER(ANON_PRIVATE))
1119                 goto whole;
1120         if (vma->vm_file == NULL)
1121                 return 0;
1122
1123         if (FILTER(MAPPED_PRIVATE))
1124                 goto whole;
1125
1126         /*
1127          * If this looks like the beginning of a DSO or executable mapping,
1128          * check for an ELF header.  If we find one, dump the first page to
1129          * aid in determining what was mapped here.
1130          */
1131         if (FILTER(ELF_HEADERS) &&
1132             vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
1133                 u32 __user *header = (u32 __user *) vma->vm_start;
1134                 u32 word;
1135                 mm_segment_t fs = get_fs();
1136                 /*
1137                  * Doing it this way gets the constant folded by GCC.
1138                  */
1139                 union {
1140                         u32 cmp;
1141                         char elfmag[SELFMAG];
1142                 } magic;
1143                 BUILD_BUG_ON(SELFMAG != sizeof word);
1144                 magic.elfmag[EI_MAG0] = ELFMAG0;
1145                 magic.elfmag[EI_MAG1] = ELFMAG1;
1146                 magic.elfmag[EI_MAG2] = ELFMAG2;
1147                 magic.elfmag[EI_MAG3] = ELFMAG3;
1148                 /*
1149                  * Switch to the user "segment" for get_user(),
1150                  * then put back what elf_core_dump() had in place.
1151                  */
1152                 set_fs(USER_DS);
1153                 if (unlikely(get_user(word, header)))
1154                         word = 0;
1155                 set_fs(fs);
1156                 if (word == magic.cmp)
1157                         return PAGE_SIZE;
1158         }
1159
1160 #undef  FILTER
1161
1162         return 0;
1163
1164 whole:
1165         return vma->vm_end - vma->vm_start;
1166 }
1167
1168 /* An ELF note in memory */
1169 struct memelfnote
1170 {
1171         const char *name;
1172         int type;
1173         unsigned int datasz;
1174         void *data;
1175 };
1176
1177 static int notesize(struct memelfnote *en)
1178 {
1179         int sz;
1180
1181         sz = sizeof(struct elf_note);
1182         sz += roundup(strlen(en->name) + 1, 4);
1183         sz += roundup(en->datasz, 4);
1184
1185         return sz;
1186 }
1187
1188 #define DUMP_WRITE(addr, nr, foffset)   \
1189         do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
1190
1191 static int alignfile(struct file *file, loff_t *foffset)
1192 {
1193         static const char buf[4] = { 0, };
1194         DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
1195         return 1;
1196 }
1197
1198 static int writenote(struct memelfnote *men, struct file *file,
1199                         loff_t *foffset)
1200 {
1201         struct elf_note en;
1202         en.n_namesz = strlen(men->name) + 1;
1203         en.n_descsz = men->datasz;
1204         en.n_type = men->type;
1205
1206         DUMP_WRITE(&en, sizeof(en), foffset);
1207         DUMP_WRITE(men->name, en.n_namesz, foffset);
1208         if (!alignfile(file, foffset))
1209                 return 0;
1210         DUMP_WRITE(men->data, men->datasz, foffset);
1211         if (!alignfile(file, foffset))
1212                 return 0;
1213
1214         return 1;
1215 }
1216 #undef DUMP_WRITE
1217
1218 static void fill_elf_header(struct elfhdr *elf, int segs,
1219                             u16 machine, u32 flags, u8 osabi)
1220 {
1221         memset(elf, 0, sizeof(*elf));
1222
1223         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1224         elf->e_ident[EI_CLASS] = ELF_CLASS;
1225         elf->e_ident[EI_DATA] = ELF_DATA;
1226         elf->e_ident[EI_VERSION] = EV_CURRENT;
1227         elf->e_ident[EI_OSABI] = ELF_OSABI;
1228
1229         elf->e_type = ET_CORE;
1230         elf->e_machine = machine;
1231         elf->e_version = EV_CURRENT;
1232         elf->e_phoff = sizeof(struct elfhdr);
1233         elf->e_flags = flags;
1234         elf->e_ehsize = sizeof(struct elfhdr);
1235         elf->e_phentsize = sizeof(struct elf_phdr);
1236         elf->e_phnum = segs;
1237
1238         return;
1239 }
1240
1241 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1242 {
1243         phdr->p_type = PT_NOTE;
1244         phdr->p_offset = offset;
1245         phdr->p_vaddr = 0;
1246         phdr->p_paddr = 0;
1247         phdr->p_filesz = sz;
1248         phdr->p_memsz = 0;
1249         phdr->p_flags = 0;
1250         phdr->p_align = 0;
1251         return;
1252 }
1253
1254 static void fill_note(struct memelfnote *note, const char *name, int type,
1255                 unsigned int sz, void *data)
1256 {
1257         note->name = name;
1258         note->type = type;
1259         note->datasz = sz;
1260         note->data = data;
1261         return;
1262 }
1263
1264 /*
1265  * fill up all the fields in prstatus from the given task struct, except
1266  * registers which need to be filled up separately.
1267  */
1268 static void fill_prstatus(struct elf_prstatus *prstatus,
1269                 struct task_struct *p, long signr)
1270 {
1271         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1272         prstatus->pr_sigpend = p->pending.signal.sig[0];
1273         prstatus->pr_sighold = p->blocked.sig[0];
1274         rcu_read_lock();
1275         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1276         rcu_read_unlock();
1277         prstatus->pr_pid = task_pid_vnr(p);
1278         prstatus->pr_pgrp = task_pgrp_vnr(p);
1279         prstatus->pr_sid = task_session_vnr(p);
1280         if (thread_group_leader(p)) {
1281                 struct task_cputime cputime;
1282
1283                 /*
1284                  * This is the record for the group leader.  It shows the
1285                  * group-wide total, not its individual thread total.
1286                  */
1287                 thread_group_cputime(p, &cputime);
1288                 cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1289                 cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1290         } else {
1291                 cputime_to_timeval(p->utime, &prstatus->pr_utime);
1292                 cputime_to_timeval(p->stime, &prstatus->pr_stime);
1293         }
1294         cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1295         cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1296 }
1297
1298 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1299                        struct mm_struct *mm)
1300 {
1301         const struct cred *cred;
1302         unsigned int i, len;
1303
1304         /* first copy the parameters from user space */
1305         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1306
1307         len = mm->arg_end - mm->arg_start;
1308         if (len >= ELF_PRARGSZ)
1309                 len = ELF_PRARGSZ-1;
1310         if (copy_from_user(&psinfo->pr_psargs,
1311                            (const char __user *)mm->arg_start, len))
1312                 return -EFAULT;
1313         for(i = 0; i < len; i++)
1314                 if (psinfo->pr_psargs[i] == 0)
1315                         psinfo->pr_psargs[i] = ' ';
1316         psinfo->pr_psargs[len] = 0;
1317
1318         rcu_read_lock();
1319         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1320         rcu_read_unlock();
1321         psinfo->pr_pid = task_pid_vnr(p);
1322         psinfo->pr_pgrp = task_pgrp_vnr(p);
1323         psinfo->pr_sid = task_session_vnr(p);
1324
1325         i = p->state ? ffz(~p->state) + 1 : 0;
1326         psinfo->pr_state = i;
1327         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1328         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1329         psinfo->pr_nice = task_nice(p);
1330         psinfo->pr_flag = p->flags;
1331         rcu_read_lock();
1332         cred = __task_cred(p);
1333         SET_UID(psinfo->pr_uid, cred->uid);
1334         SET_GID(psinfo->pr_gid, cred->gid);
1335         rcu_read_unlock();
1336         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1337
1338         return 0;
1339 }
1340
1341 static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
1342 {
1343         elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
1344         int i = 0;
1345         do
1346                 i += 2;
1347         while (auxv[i - 2] != AT_NULL);
1348         fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
1349 }
1350
1351 #ifdef CORE_DUMP_USE_REGSET
1352 #include <linux/regset.h>
1353
1354 struct elf_thread_core_info {
1355         struct elf_thread_core_info *next;
1356         struct task_struct *task;
1357         struct elf_prstatus prstatus;
1358         struct memelfnote notes[0];
1359 };
1360
1361 struct elf_note_info {
1362         struct elf_thread_core_info *thread;
1363         struct memelfnote psinfo;
1364         struct memelfnote auxv;
1365         size_t size;
1366         int thread_notes;
1367 };
1368
1369 /*
1370  * When a regset has a writeback hook, we call it on each thread before
1371  * dumping user memory.  On register window machines, this makes sure the
1372  * user memory backing the register data is up to date before we read it.
1373  */
1374 static void do_thread_regset_writeback(struct task_struct *task,
1375                                        const struct user_regset *regset)
1376 {
1377         if (regset->writeback)
1378                 regset->writeback(task, regset, 1);
1379 }
1380
1381 static int fill_thread_core_info(struct elf_thread_core_info *t,
1382                                  const struct user_regset_view *view,
1383                                  long signr, size_t *total)
1384 {
1385         unsigned int i;
1386
1387         /*
1388          * NT_PRSTATUS is the one special case, because the regset data
1389          * goes into the pr_reg field inside the note contents, rather
1390          * than being the whole note contents.  We fill the reset in here.
1391          * We assume that regset 0 is NT_PRSTATUS.
1392          */
1393         fill_prstatus(&t->prstatus, t->task, signr);
1394         (void) view->regsets[0].get(t->task, &view->regsets[0],
1395                                     0, sizeof(t->prstatus.pr_reg),
1396                                     &t->prstatus.pr_reg, NULL);
1397
1398         fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
1399                   sizeof(t->prstatus), &t->prstatus);
1400         *total += notesize(&t->notes[0]);
1401
1402         do_thread_regset_writeback(t->task, &view->regsets[0]);
1403
1404         /*
1405          * Each other regset might generate a note too.  For each regset
1406          * that has no core_note_type or is inactive, we leave t->notes[i]
1407          * all zero and we'll know to skip writing it later.
1408          */
1409         for (i = 1; i < view->n; ++i) {
1410                 const struct user_regset *regset = &view->regsets[i];
1411                 do_thread_regset_writeback(t->task, regset);
1412                 if (regset->core_note_type &&
1413                     (!regset->active || regset->active(t->task, regset))) {
1414                         int ret;
1415                         size_t size = regset->n * regset->size;
1416                         void *data = kmalloc(size, GFP_KERNEL);
1417                         if (unlikely(!data))
1418                                 return 0;
1419                         ret = regset->get(t->task, regset,
1420                                           0, size, data, NULL);
1421                         if (unlikely(ret))
1422                                 kfree(data);
1423                         else {
1424                                 if (regset->core_note_type != NT_PRFPREG)
1425                                         fill_note(&t->notes[i], "LINUX",
1426                                                   regset->core_note_type,
1427                                                   size, data);
1428                                 else {
1429                                         t->prstatus.pr_fpvalid = 1;
1430                                         fill_note(&t->notes[i], "CORE",
1431                                                   NT_PRFPREG, size, data);
1432                                 }
1433                                 *total += notesize(&t->notes[i]);
1434                         }
1435                 }
1436         }
1437
1438         return 1;
1439 }
1440
1441 static int fill_note_info(struct elfhdr *elf, int phdrs,
1442                           struct elf_note_info *info,
1443                           long signr, struct pt_regs *regs)
1444 {
1445         struct task_struct *dump_task = current;
1446         const struct user_regset_view *view = task_user_regset_view(dump_task);
1447         struct elf_thread_core_info *t;
1448         struct elf_prpsinfo *psinfo;
1449         struct core_thread *ct;
1450         unsigned int i;
1451
1452         info->size = 0;
1453         info->thread = NULL;
1454
1455         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1456         if (psinfo == NULL)
1457                 return 0;
1458
1459         fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1460
1461         /*
1462          * Figure out how many notes we're going to need for each thread.
1463          */
1464         info->thread_notes = 0;
1465         for (i = 0; i < view->n; ++i)
1466                 if (view->regsets[i].core_note_type != 0)
1467                         ++info->thread_notes;
1468
1469         /*
1470          * Sanity check.  We rely on regset 0 being in NT_PRSTATUS,
1471          * since it is our one special case.
1472          */
1473         if (unlikely(info->thread_notes == 0) ||
1474             unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
1475                 WARN_ON(1);
1476                 return 0;
1477         }
1478
1479         /*
1480          * Initialize the ELF file header.
1481          */
1482         fill_elf_header(elf, phdrs,
1483                         view->e_machine, view->e_flags, view->ei_osabi);
1484
1485         /*
1486          * Allocate a structure for each thread.
1487          */
1488         for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
1489                 t = kzalloc(offsetof(struct elf_thread_core_info,
1490                                      notes[info->thread_notes]),
1491                             GFP_KERNEL);
1492                 if (unlikely(!t))
1493                         return 0;
1494
1495                 t->task = ct->task;
1496                 if (ct->task == dump_task || !info->thread) {
1497                         t->next = info->thread;
1498                         info->thread = t;
1499                 } else {
1500                         /*
1501                          * Make sure to keep the original task at
1502                          * the head of the list.
1503                          */
1504                         t->next = info->thread->next;
1505                         info->thread->next = t;
1506                 }
1507         }
1508
1509         /*
1510          * Now fill in each thread's information.
1511          */
1512         for (t = info->thread; t != NULL; t = t->next)
1513                 if (!fill_thread_core_info(t, view, signr, &info->size))
1514                         return 0;
1515
1516         /*
1517          * Fill in the two process-wide notes.
1518          */
1519         fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
1520         info->size += notesize(&info->psinfo);
1521
1522         fill_auxv_note(&info->auxv, current->mm);
1523         info->size += notesize(&info->auxv);
1524
1525         return 1;
1526 }
1527
1528 static size_t get_note_info_size(struct elf_note_info *info)
1529 {
1530         return info->size;
1531 }
1532
1533 /*
1534  * Write all the notes for each thread.  When writing the first thread, the
1535  * process-wide notes are interleaved after the first thread-specific note.
1536  */
1537 static int write_note_info(struct elf_note_info *info,
1538                            struct file *file, loff_t *foffset)
1539 {
1540         bool first = 1;
1541         struct elf_thread_core_info *t = info->thread;
1542
1543         do {
1544                 int i;
1545
1546                 if (!writenote(&t->notes[0], file, foffset))
1547                         return 0;
1548
1549                 if (first && !writenote(&info->psinfo, file, foffset))
1550                         return 0;
1551                 if (first && !writenote(&info->auxv, file, foffset))
1552                         return 0;
1553
1554                 for (i = 1; i < info->thread_notes; ++i)
1555                         if (t->notes[i].data &&
1556                             !writenote(&t->notes[i], file, foffset))
1557                                 return 0;
1558
1559                 first = 0;
1560                 t = t->next;
1561         } while (t);
1562
1563         return 1;
1564 }
1565
1566 static void free_note_info(struct elf_note_info *info)
1567 {
1568         struct elf_thread_core_info *threads = info->thread;
1569         while (threads) {
1570                 unsigned int i;
1571                 struct elf_thread_core_info *t = threads;
1572                 threads = t->next;
1573                 WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
1574                 for (i = 1; i < info->thread_notes; ++i)
1575                         kfree(t->notes[i].data);
1576                 kfree(t);
1577         }
1578         kfree(info->psinfo.data);
1579 }
1580
1581 #else
1582
1583 /* Here is the structure in which status of each thread is captured. */
1584 struct elf_thread_status
1585 {
1586         struct list_head list;
1587         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1588         elf_fpregset_t fpu;             /* NT_PRFPREG */
1589         struct task_struct *thread;
1590 #ifdef ELF_CORE_COPY_XFPREGS
1591         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1592 #endif
1593         struct memelfnote notes[3];
1594         int num_notes;
1595 };
1596
1597 /*
1598  * In order to add the specific thread information for the elf file format,
1599  * we need to keep a linked list of every threads pr_status and then create
1600  * a single section for them in the final core file.
1601  */
1602 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1603 {
1604         int sz = 0;
1605         struct task_struct *p = t->thread;
1606         t->num_notes = 0;
1607
1608         fill_prstatus(&t->prstatus, p, signr);
1609         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1610
1611         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1612                   &(t->prstatus));
1613         t->num_notes++;
1614         sz += notesize(&t->notes[0]);
1615
1616         if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
1617                                                                 &t->fpu))) {
1618                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1619                           &(t->fpu));
1620                 t->num_notes++;
1621                 sz += notesize(&t->notes[1]);
1622         }
1623
1624 #ifdef ELF_CORE_COPY_XFPREGS
1625         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1626                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1627                           sizeof(t->xfpu), &t->xfpu);
1628                 t->num_notes++;
1629                 sz += notesize(&t->notes[2]);
1630         }
1631 #endif
1632         return sz;
1633 }
1634
1635 struct elf_note_info {
1636         struct memelfnote *notes;
1637         struct elf_prstatus *prstatus;  /* NT_PRSTATUS */
1638         struct elf_prpsinfo *psinfo;    /* NT_PRPSINFO */
1639         struct list_head thread_list;
1640         elf_fpregset_t *fpu;
1641 #ifdef ELF_CORE_COPY_XFPREGS
1642         elf_fpxregset_t *xfpu;
1643 #endif
1644         int thread_status_size;
1645         int numnote;
1646 };
1647
1648 static int elf_note_info_init(struct elf_note_info *info)
1649 {
1650         memset(info, 0, sizeof(*info));
1651         INIT_LIST_HEAD(&info->thread_list);
1652
1653         /* Allocate space for six ELF notes */
1654         info->notes = kmalloc(6 * sizeof(struct memelfnote), GFP_KERNEL);
1655         if (!info->notes)
1656                 return 0;
1657         info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
1658         if (!info->psinfo)
1659                 goto notes_free;
1660         info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
1661         if (!info->prstatus)
1662                 goto psinfo_free;
1663         info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
1664         if (!info->fpu)
1665                 goto prstatus_free;
1666 #ifdef ELF_CORE_COPY_XFPREGS
1667         info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
1668         if (!info->xfpu)
1669                 goto fpu_free;
1670 #endif
1671         return 1;
1672 #ifdef ELF_CORE_COPY_XFPREGS
1673  fpu_free:
1674         kfree(info->fpu);
1675 #endif
1676  prstatus_free:
1677         kfree(info->prstatus);
1678  psinfo_free:
1679         kfree(info->psinfo);
1680  notes_free:
1681         kfree(info->notes);
1682         return 0;
1683 }
1684
1685 static int fill_note_info(struct elfhdr *elf, int phdrs,
1686                           struct elf_note_info *info,
1687                           long signr, struct pt_regs *regs)
1688 {
1689         struct list_head *t;
1690
1691         if (!elf_note_info_init(info))
1692                 return 0;
1693
1694         if (signr) {
1695                 struct core_thread *ct;
1696                 struct elf_thread_status *ets;
1697
1698                 for (ct = current->mm->core_state->dumper.next;
1699                                                 ct; ct = ct->next) {
1700                         ets = kzalloc(sizeof(*ets), GFP_KERNEL);
1701                         if (!ets)
1702                                 return 0;
1703
1704                         ets->thread = ct->task;
1705                         list_add(&ets->list, &info->thread_list);
1706                 }
1707
1708                 list_for_each(t, &info->thread_list) {
1709                         int sz;
1710
1711                         ets = list_entry(t, struct elf_thread_status, list);
1712                         sz = elf_dump_thread_status(signr, ets);
1713                         info->thread_status_size += sz;
1714                 }
1715         }
1716         /* now collect the dump for the current */
1717         memset(info->prstatus, 0, sizeof(*info->prstatus));
1718         fill_prstatus(info->prstatus, current, signr);
1719         elf_core_copy_regs(&info->prstatus->pr_reg, regs);
1720
1721         /* Set up header */
1722         fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS, ELF_OSABI);
1723
1724         /*
1725          * Set up the notes in similar form to SVR4 core dumps made
1726          * with info from their /proc.
1727          */
1728
1729         fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
1730                   sizeof(*info->prstatus), info->prstatus);
1731         fill_psinfo(info->psinfo, current->group_leader, current->mm);
1732         fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
1733                   sizeof(*info->psinfo), info->psinfo);
1734
1735         info->numnote = 2;
1736
1737         fill_auxv_note(&info->notes[info->numnote++], current->mm);
1738
1739         /* Try to dump the FPU. */
1740         info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs,
1741                                                                info->fpu);
1742         if (info->prstatus->pr_fpvalid)
1743                 fill_note(info->notes + info->numnote++,
1744                           "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
1745 #ifdef ELF_CORE_COPY_XFPREGS
1746         if (elf_core_copy_task_xfpregs(current, info->xfpu))
1747                 fill_note(info->notes + info->numnote++,
1748                           "LINUX", ELF_CORE_XFPREG_TYPE,
1749                           sizeof(*info->xfpu), info->xfpu);
1750 #endif
1751
1752         return 1;
1753 }
1754
1755 static size_t get_note_info_size(struct elf_note_info *info)
1756 {
1757         int sz = 0;
1758         int i;
1759
1760         for (i = 0; i < info->numnote; i++)
1761                 sz += notesize(info->notes + i);
1762
1763         sz += info->thread_status_size;
1764
1765         return sz;
1766 }
1767
1768 static int write_note_info(struct elf_note_info *info,
1769                            struct file *file, loff_t *foffset)
1770 {
1771         int i;
1772         struct list_head *t;
1773
1774         for (i = 0; i < info->numnote; i++)
1775                 if (!writenote(info->notes + i, file, foffset))
1776                         return 0;
1777
1778         /* write out the thread status notes section */
1779         list_for_each(t, &info->thread_list) {
1780                 struct elf_thread_status *tmp =
1781                                 list_entry(t, struct elf_thread_status, list);
1782
1783                 for (i = 0; i < tmp->num_notes; i++)
1784                         if (!writenote(&tmp->notes[i], file, foffset))
1785                                 return 0;
1786         }
1787
1788         return 1;
1789 }
1790
1791 static void free_note_info(struct elf_note_info *info)
1792 {
1793         while (!list_empty(&info->thread_list)) {
1794                 struct list_head *tmp = info->thread_list.next;
1795                 list_del(tmp);
1796                 kfree(list_entry(tmp, struct elf_thread_status, list));
1797         }
1798
1799         kfree(info->prstatus);
1800         kfree(info->psinfo);
1801         kfree(info->notes);
1802         kfree(info->fpu);
1803 #ifdef ELF_CORE_COPY_XFPREGS
1804         kfree(info->xfpu);
1805 #endif
1806 }
1807
1808 #endif
1809
1810 static struct vm_area_struct *first_vma(struct task_struct *tsk,
1811                                         struct vm_area_struct *gate_vma)
1812 {
1813         struct vm_area_struct *ret = tsk->mm->mmap;
1814
1815         if (ret)
1816                 return ret;
1817         return gate_vma;
1818 }
1819 /*
1820  * Helper function for iterating across a vma list.  It ensures that the caller
1821  * will visit `gate_vma' prior to terminating the search.
1822  */
1823 static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
1824                                         struct vm_area_struct *gate_vma)
1825 {
1826         struct vm_area_struct *ret;
1827
1828         ret = this_vma->vm_next;
1829         if (ret)
1830                 return ret;
1831         if (this_vma == gate_vma)
1832                 return NULL;
1833         return gate_vma;
1834 }
1835
1836 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1837                              elf_addr_t e_shoff, int segs)
1838 {
1839         elf->e_shoff = e_shoff;
1840         elf->e_shentsize = sizeof(*shdr4extnum);
1841         elf->e_shnum = 1;
1842         elf->e_shstrndx = SHN_UNDEF;
1843
1844         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1845
1846         shdr4extnum->sh_type = SHT_NULL;
1847         shdr4extnum->sh_size = elf->e_shnum;
1848         shdr4extnum->sh_link = elf->e_shstrndx;
1849         shdr4extnum->sh_info = segs;
1850 }
1851
1852 static size_t elf_core_vma_data_size(struct vm_area_struct *gate_vma,
1853                                      unsigned long mm_flags)
1854 {
1855         struct vm_area_struct *vma;
1856         size_t size = 0;
1857
1858         for (vma = first_vma(current, gate_vma); vma != NULL;
1859              vma = next_vma(vma, gate_vma))
1860                 size += vma_dump_size(vma, mm_flags);
1861         return size;
1862 }
1863
1864 /*
1865  * Actual dumper
1866  *
1867  * This is a two-pass process; first we find the offsets of the bits,
1868  * and then they are actually written out.  If we run out of core limit
1869  * we just truncate.
1870  */
1871 static int elf_core_dump(struct coredump_params *cprm)
1872 {
1873         int has_dumped = 0;
1874         mm_segment_t fs;
1875         int segs;
1876         size_t size = 0;
1877         struct vm_area_struct *vma, *gate_vma;
1878         struct elfhdr *elf = NULL;
1879         loff_t offset = 0, dataoff, foffset;
1880         struct elf_note_info info;
1881         struct elf_phdr *phdr4note = NULL;
1882         struct elf_shdr *shdr4extnum = NULL;
1883         Elf_Half e_phnum;
1884         elf_addr_t e_shoff;
1885
1886         /*
1887          * We no longer stop all VM operations.
1888          *
1889          * This is because those proceses that could possibly change map_count
1890          * or the mmap / vma pages are now blocked in do_exit on current
1891          * finishing this core dump.
1892          *
1893          * Only ptrace can touch these memory addresses, but it doesn't change
1894          * the map_count or the pages allocated. So no possibility of crashing
1895          * exists while dumping the mm->vm_next areas to the core file.
1896          */
1897
1898         /* alloc memory for large data structures: too large to be on stack */
1899         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1900         if (!elf)
1901                 goto out;
1902         /*
1903          * The number of segs are recored into ELF header as 16bit value.
1904          * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
1905          */
1906         segs = current->mm->map_count;
1907         segs += elf_core_extra_phdrs();
1908
1909         gate_vma = get_gate_vma(current);
1910         if (gate_vma != NULL)
1911                 segs++;
1912
1913         /* for notes section */
1914         segs++;
1915
1916         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1917          * this, kernel supports extended numbering. Have a look at
1918          * include/linux/elf.h for further information. */
1919         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1920
1921         /*
1922          * Collect all the non-memory information about the process for the
1923          * notes.  This also sets up the file header.
1924          */
1925         if (!fill_note_info(elf, e_phnum, &info, cprm->signr, cprm->regs))
1926                 goto cleanup;
1927
1928         has_dumped = 1;
1929         current->flags |= PF_DUMPCORE;
1930
1931         fs = get_fs();
1932         set_fs(KERNEL_DS);
1933
1934         offset += sizeof(*elf);                         /* Elf header */
1935         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
1936         foffset = offset;
1937
1938         /* Write notes phdr entry */
1939         {
1940                 size_t sz = get_note_info_size(&info);
1941
1942                 sz += elf_coredump_extra_notes_size();
1943
1944                 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1945                 if (!phdr4note)
1946                         goto end_coredump;
1947
1948                 fill_elf_note_phdr(phdr4note, sz, offset);
1949                 offset += sz;
1950         }
1951
1952         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1953
1954         offset += elf_core_vma_data_size(gate_vma, cprm->mm_flags);
1955         offset += elf_core_extra_data_size();
1956         e_shoff = offset;
1957
1958         if (e_phnum == PN_XNUM) {
1959                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1960                 if (!shdr4extnum)
1961                         goto end_coredump;
1962                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1963         }
1964
1965         offset = dataoff;
1966
1967         size += sizeof(*elf);
1968         if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
1969                 goto end_coredump;
1970
1971         size += sizeof(*phdr4note);
1972         if (size > cprm->limit
1973             || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note)))
1974                 goto end_coredump;
1975
1976         /* Write program headers for segments dump */
1977         for (vma = first_vma(current, gate_vma); vma != NULL;
1978                         vma = next_vma(vma, gate_vma)) {
1979                 struct elf_phdr phdr;
1980
1981                 phdr.p_type = PT_LOAD;
1982                 phdr.p_offset = offset;
1983                 phdr.p_vaddr = vma->vm_start;
1984                 phdr.p_paddr = 0;
1985                 phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags);
1986                 phdr.p_memsz = vma->vm_end - vma->vm_start;
1987                 offset += phdr.p_filesz;
1988                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1989                 if (vma->vm_flags & VM_WRITE)
1990                         phdr.p_flags |= PF_W;
1991                 if (vma->vm_flags & VM_EXEC)
1992                         phdr.p_flags |= PF_X;
1993                 phdr.p_align = ELF_EXEC_PAGESIZE;
1994
1995                 size += sizeof(phdr);
1996                 if (size > cprm->limit
1997                     || !dump_write(cprm->file, &phdr, sizeof(phdr)))
1998                         goto end_coredump;
1999         }
2000
2001         if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
2002                 goto end_coredump;
2003
2004         /* write out the notes section */
2005         if (!write_note_info(&info, cprm->file, &foffset))
2006                 goto end_coredump;
2007
2008         if (elf_coredump_extra_notes_write(cprm->file, &foffset))
2009                 goto end_coredump;
2010
2011         /* Align to page */
2012         if (!dump_seek(cprm->file, dataoff - foffset))
2013                 goto end_coredump;
2014
2015         for (vma = first_vma(current, gate_vma); vma != NULL;
2016                         vma = next_vma(vma, gate_vma)) {
2017                 unsigned long addr;
2018                 unsigned long end;
2019
2020                 end = vma->vm_start + vma_dump_size(vma, cprm->mm_flags);
2021
2022                 for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
2023                         struct page *page;
2024                         int stop;
2025
2026                         page = get_dump_page(addr);
2027                         if (page) {
2028                                 void *kaddr = kmap(page);
2029                                 stop = ((size += PAGE_SIZE) > cprm->limit) ||
2030                                         !dump_write(cprm->file, kaddr,
2031                                                     PAGE_SIZE);
2032                                 kunmap(page);
2033                                 page_cache_release(page);
2034                         } else
2035                                 stop = !dump_seek(cprm->file, PAGE_SIZE);
2036                         if (stop)
2037                                 goto end_coredump;
2038                 }
2039         }
2040
2041         if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
2042                 goto end_coredump;
2043
2044         if (e_phnum == PN_XNUM) {
2045                 size += sizeof(*shdr4extnum);
2046                 if (size > cprm->limit
2047                     || !dump_write(cprm->file, shdr4extnum,
2048                                    sizeof(*shdr4extnum)))
2049                         goto end_coredump;
2050         }
2051
2052 end_coredump:
2053         set_fs(fs);
2054
2055 cleanup:
2056         free_note_info(&info);
2057         kfree(shdr4extnum);
2058         kfree(phdr4note);
2059         kfree(elf);
2060 out:
2061         return has_dumped;
2062 }
2063
2064 #endif          /* CONFIG_ELF_CORE */
2065
2066 static int __init init_elf_binfmt(void)
2067 {
2068         return register_binfmt(&elf_format);
2069 }
2070
2071 static void __exit exit_elf_binfmt(void)
2072 {
2073         /* Remove the COFF and ELF loaders. */
2074         unregister_binfmt(&elf_format);
2075 }
2076
2077 core_initcall(init_elf_binfmt);
2078 module_exit(exit_elf_binfmt);
2079 MODULE_LICENSE("GPL");