fs/binfmt_elf_fdpic.c

   1 /* binfmt_elf_fdpic.c: FDPIC ELF binary format
   2  *
   3  * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  * Derived from binfmt_elf.c
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14
  15 #include <linux/fs.h>
  16 #include <linux/stat.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/coredump.h>
  19 #include <linux/sched/task_stack.h>
  20 #include <linux/sched/cputime.h>
  21 #include <linux/mm.h>
  22 #include <linux/mman.h>
  23 #include <linux/errno.h>
  24 #include <linux/signal.h>
  25 #include <linux/binfmts.h>
  26 #include <linux/string.h>
  27 #include <linux/file.h>
  28 #include <linux/fcntl.h>
  29 #include <linux/slab.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/security.h>
  32 #include <linux/highmem.h>
  33 #include <linux/highuid.h>
  34 #include <linux/personality.h>
  35 #include <linux/ptrace.h>
  36 #include <linux/init.h>
  37 #include <linux/elf.h>
  38 #include <linux/elf-fdpic.h>
  39 #include <linux/elfcore.h>
  40 #include <linux/coredump.h>
  41 #include <linux/dax.h>
  42
  43 #include <linux/uaccess.h>
  44 #include <asm/param.h>
  45 #include <asm/pgalloc.h>
  46
  47 typedef char *elf_caddr_t;
  48
  49 #if 0
  50 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  51 #else
  52 #define kdebug(fmt, ...) do {} while(0)
  53 #endif
  54
  55 #if 0
  56 #define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  57 #else
  58 #define kdcore(fmt, ...) do {} while(0)
  59 #endif
  60
  61 MODULE_LICENSE("GPL");
  62
  63 static int load_elf_fdpic_binary(struct linux_binprm *);
  64 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
  65 static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
  66                               struct mm_struct *, const char *);
  67
  68 static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
  69                                    struct elf_fdpic_params *,
  70                                    struct elf_fdpic_params *);
  71
  72 #ifndef CONFIG_MMU
  73 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
  74                                                    struct file *,
  75                                                    struct mm_struct *);
  76 #endif
  77
  78 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
  79                                              struct file *, struct mm_struct *);
  80
  81 #ifdef CONFIG_ELF_CORE
  82 static int elf_fdpic_core_dump(struct coredump_params *cprm);
  83 #endif
  84
  85 static struct linux_binfmt elf_fdpic_format = {
  86         .module         = THIS_MODULE,
  87         .load_binary    = load_elf_fdpic_binary,
  88 #ifdef CONFIG_ELF_CORE
  89         .core_dump      = elf_fdpic_core_dump,
  90 #endif
  91         .min_coredump   = ELF_EXEC_PAGESIZE,
  92 };
  93
  94 static int __init init_elf_fdpic_binfmt(void)
  95 {
  96         register_binfmt(&elf_fdpic_format);
  97         return 0;
  98 }
  99
 100 static void __exit exit_elf_fdpic_binfmt(void)
 101 {
 102         unregister_binfmt(&elf_fdpic_format);
 103 }
 104
 105 core_initcall(init_elf_fdpic_binfmt);
 106 module_exit(exit_elf_fdpic_binfmt);
 107
 108 static int is_elf(struct elfhdr *hdr, struct file *file)
 109 {
 110         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
 111                 return 0;
 112         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
 113                 return 0;
 114         if (!elf_check_arch(hdr))
 115                 return 0;
 116         if (!file->f_op->mmap)
 117                 return 0;
 118         return 1;
 119 }
 120
 121 #ifndef elf_check_fdpic
 122 #define elf_check_fdpic(x) 0
 123 #endif
 124
 125 #ifndef elf_check_const_displacement
 126 #define elf_check_const_displacement(x) 0
 127 #endif
 128
 129 static int is_constdisp(struct elfhdr *hdr)
 130 {
 131         if (!elf_check_fdpic(hdr))
 132                 return 1;
 133         if (elf_check_const_displacement(hdr))
 134                 return 1;
 135         return 0;
 136 }
 137
 138 /*****************************************************************************/
 139 /*
 140  * read the program headers table into memory
 141  */
 142 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
 143                                  struct file *file)
 144 {
 145         struct elf32_phdr *phdr;
 146         unsigned long size;
 147         int retval, loop;
 148         loff_t pos = params->hdr.e_phoff;
 149
 150         if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 151                 return -ENOMEM;
 152         if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
 153                 return -ENOMEM;
 154
 155         size = params->hdr.e_phnum * sizeof(struct elf_phdr);
 156         params->phdrs = kmalloc(size, GFP_KERNEL);
 157         if (!params->phdrs)
 158                 return -ENOMEM;
 159
 160         retval = kernel_read(file, params->phdrs, size, &pos);
 161         if (unlikely(retval != size))
 162                 return retval < 0 ? retval : -ENOEXEC;
 163
 164         /* determine stack size for this binary */
 165         phdr = params->phdrs;
 166         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 167                 if (phdr->p_type != PT_GNU_STACK)
 168                         continue;
 169
 170                 if (phdr->p_flags & PF_X)
 171                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
 172                 else
 173                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
 174
 175                 params->stack_size = phdr->p_memsz;
 176                 break;
 177         }
 178
 179         return 0;
 180 }
 181
 182 /*****************************************************************************/
 183 /*
 184  * load an fdpic binary into various bits of memory
 185  */
 186 static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 187 {
 188         struct elf_fdpic_params exec_params, interp_params;
 189         struct pt_regs *regs = current_pt_regs();
 190         struct elf_phdr *phdr;
 191         unsigned long stack_size, entryaddr;
 192 #ifdef ELF_FDPIC_PLAT_INIT
 193         unsigned long dynaddr;
 194 #endif
 195 #ifndef CONFIG_MMU
 196         unsigned long stack_prot;
 197 #endif
 198         struct file *interpreter = NULL; /* to shut gcc up */
 199         char *interpreter_name = NULL;
 200         int executable_stack;
 201         int retval, i;
 202         loff_t pos;
 203
 204         kdebug("____ LOAD %d ____", current->pid);
 205
 206         memset(&exec_params, 0, sizeof(exec_params));
 207         memset(&interp_params, 0, sizeof(interp_params));
 208
 209         exec_params.hdr = *(struct elfhdr *) bprm->buf;
 210         exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
 211
 212         /* check that this is a binary we know how to deal with */
 213         retval = -ENOEXEC;
 214         if (!is_elf(&exec_params.hdr, bprm->file))
 215                 goto error;
 216         if (!elf_check_fdpic(&exec_params.hdr)) {
 217 #ifdef CONFIG_MMU
 218                 /* binfmt_elf handles non-fdpic elf except on nommu */
 219                 goto error;
 220 #else
 221                 /* nommu can only load ET_DYN (PIE) ELF */
 222                 if (exec_params.hdr.e_type != ET_DYN)
 223                         goto error;
 224 #endif
 225         }
 226
 227         /* read the program header table */
 228         retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
 229         if (retval < 0)
 230                 goto error;
 231
 232         /* scan for a program header that specifies an interpreter */
 233         phdr = exec_params.phdrs;
 234
 235         for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
 236                 switch (phdr->p_type) {
 237                 case PT_INTERP:
 238                         retval = -ENOMEM;
 239                         if (phdr->p_filesz > PATH_MAX)
 240                                 goto error;
 241                         retval = -ENOENT;
 242                         if (phdr->p_filesz < 2)
 243                                 goto error;
 244
 245                         /* read the name of the interpreter into memory */
 246                         interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
 247                         if (!interpreter_name)
 248                                 goto error;
 249
 250                         pos = phdr->p_offset;
 251                         retval = kernel_read(bprm->file, interpreter_name,
 252                                              phdr->p_filesz, &pos);
 253                         if (unlikely(retval != phdr->p_filesz)) {
 254                                 if (retval >= 0)
 255                                         retval = -ENOEXEC;
 256                                 goto error;
 257                         }
 258
 259                         retval = -ENOENT;
 260                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
 261                                 goto error;
 262
 263                         kdebug("Using ELF interpreter %s", interpreter_name);
 264
 265                         /* replace the program with the interpreter */
 266                         interpreter = open_exec(interpreter_name);
 267                         retval = PTR_ERR(interpreter);
 268                         if (IS_ERR(interpreter)) {
 269                                 interpreter = NULL;
 270                                 goto error;
 271                         }
 272
 273                         /*
 274                          * If the binary is not readable then enforce
 275                          * mm->dumpable = 0 regardless of the interpreter's
 276                          * permissions.
 277                          */
 278                         would_dump(bprm, interpreter);
 279
 280                         pos = 0;
 281                         retval = kernel_read(interpreter, bprm->buf,
 282                                         BINPRM_BUF_SIZE, &pos);
 283                         if (unlikely(retval != BINPRM_BUF_SIZE)) {
 284                                 if (retval >= 0)
 285                                         retval = -ENOEXEC;
 286                                 goto error;
 287                         }
 288
 289                         interp_params.hdr = *((struct elfhdr *) bprm->buf);
 290                         break;
 291
 292                 case PT_LOAD:
 293 #ifdef CONFIG_MMU
 294                         if (exec_params.load_addr == 0)
 295                                 exec_params.load_addr = phdr->p_vaddr;
 296 #endif
 297                         break;
 298                 }
 299
 300         }
 301
 302         if (is_constdisp(&exec_params.hdr))
 303                 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 304
 305         /* perform insanity checks on the interpreter */
 306         if (interpreter_name) {
 307                 retval = -ELIBBAD;
 308                 if (!is_elf(&interp_params.hdr, interpreter))
 309                         goto error;
 310
 311                 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
 312
 313                 /* read the interpreter's program header table */
 314                 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
 315                 if (retval < 0)
 316                         goto error;
 317         }
 318
 319         stack_size = exec_params.stack_size;
 320         if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 321                 executable_stack = EXSTACK_ENABLE_X;
 322         else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 323                 executable_stack = EXSTACK_DISABLE_X;
 324         else
 325                 executable_stack = EXSTACK_DEFAULT;
 326
 327         if (stack_size == 0) {
 328                 stack_size = interp_params.stack_size;
 329                 if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 330                         executable_stack = EXSTACK_ENABLE_X;
 331                 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 332                         executable_stack = EXSTACK_DISABLE_X;
 333                 else
 334                         executable_stack = EXSTACK_DEFAULT;
 335         }
 336
 337         retval = -ENOEXEC;
 338         if (stack_size == 0)
 339                 stack_size = 131072UL; /* same as exec.c's default commit */
 340
 341         if (is_constdisp(&interp_params.hdr))
 342                 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 343
 344         /* flush all traces of the currently running executable */
 345         retval = flush_old_exec(bprm);
 346         if (retval)
 347                 goto error;
 348
 349         /* there's now no turning back... the old userspace image is dead,
 350          * defunct, deceased, etc.
 351          */
 352         if (elf_check_fdpic(&exec_params.hdr))
 353                 set_personality(PER_LINUX_FDPIC);
 354         else
 355                 set_personality(PER_LINUX);
 356         if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
 357                 current->personality |= READ_IMPLIES_EXEC;
 358
 359         setup_new_exec(bprm);
 360
 361         set_binfmt(&elf_fdpic_format);
 362
 363         current->mm->start_code = 0;
 364         current->mm->end_code = 0;
 365         current->mm->start_stack = 0;
 366         current->mm->start_data = 0;
 367         current->mm->end_data = 0;
 368         current->mm->context.exec_fdpic_loadmap = 0;
 369         current->mm->context.interp_fdpic_loadmap = 0;
 370
 371 #ifdef CONFIG_MMU
 372         elf_fdpic_arch_lay_out_mm(&exec_params,
 373                                   &interp_params,
 374                                   &current->mm->start_stack,
 375                                   &current->mm->start_brk);
 376
 377         retval = setup_arg_pages(bprm, current->mm->start_stack,
 378                                  executable_stack);
 379         if (retval < 0)
 380                 goto error;
 381 #endif
 382
 383         /* load the executable and interpreter into memory */
 384         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
 385                                     "executable");
 386         if (retval < 0)
 387                 goto error;
 388
 389         if (interpreter_name) {
 390                 retval = elf_fdpic_map_file(&interp_params, interpreter,
 391                                             current->mm, "interpreter");
 392                 if (retval < 0) {
 393                         printk(KERN_ERR "Unable to load interpreter\n");
 394                         goto error;
 395                 }
 396
 397                 allow_write_access(interpreter);
 398                 fput(interpreter);
 399                 interpreter = NULL;
 400         }
 401
 402 #ifdef CONFIG_MMU
 403         if (!current->mm->start_brk)
 404                 current->mm->start_brk = current->mm->end_data;
 405
 406         current->mm->brk = current->mm->start_brk =
 407                 PAGE_ALIGN(current->mm->start_brk);
 408
 409 #else
 410         /* create a stack area and zero-size brk area */
 411         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 412         if (stack_size < PAGE_SIZE * 2)
 413                 stack_size = PAGE_SIZE * 2;
 414
 415         stack_prot = PROT_READ | PROT_WRITE;
 416         if (executable_stack == EXSTACK_ENABLE_X ||
 417             (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
 418                 stack_prot |= PROT_EXEC;
 419
 420         current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
 421                                          MAP_PRIVATE | MAP_ANONYMOUS |
 422                                          MAP_UNINITIALIZED | MAP_GROWSDOWN,
 423                                          0);
 424
 425         if (IS_ERR_VALUE(current->mm->start_brk)) {
 426                 retval = current->mm->start_brk;
 427                 current->mm->start_brk = 0;
 428                 goto error;
 429         }
 430
 431         current->mm->brk = current->mm->start_brk;
 432         current->mm->context.end_brk = current->mm->start_brk;
 433         current->mm->start_stack = current->mm->start_brk + stack_size;
 434 #endif
 435
 436         install_exec_creds(bprm);
 437         if (create_elf_fdpic_tables(bprm, current->mm,
 438                                     &exec_params, &interp_params) < 0)
 439                 goto error;
 440
 441         kdebug("- start_code  %lx", current->mm->start_code);
 442         kdebug("- end_code    %lx", current->mm->end_code);
 443         kdebug("- start_data  %lx", current->mm->start_data);
 444         kdebug("- end_data    %lx", current->mm->end_data);
 445         kdebug("- start_brk   %lx", current->mm->start_brk);
 446         kdebug("- brk         %lx", current->mm->brk);
 447         kdebug("- start_stack %lx", current->mm->start_stack);
 448
 449 #ifdef ELF_FDPIC_PLAT_INIT
 450         /*
 451          * The ABI may specify that certain registers be set up in special
 452          * ways (on i386 %edx is the address of a DT_FINI function, for
 453          * example.  This macro performs whatever initialization to
 454          * the regs structure is required.
 455          */
 456         dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
 457         ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
 458                             dynaddr);
 459 #endif
 460
 461         /* everything is now ready... get the userspace context ready to roll */
 462         entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
 463         start_thread(regs, entryaddr, current->mm->start_stack);
 464
 465         retval = 0;
 466
 467 error:
 468         if (interpreter) {
 469                 allow_write_access(interpreter);
 470                 fput(interpreter);
 471         }
 472         kfree(interpreter_name);
 473         kfree(exec_params.phdrs);
 474         kfree(exec_params.loadmap);
 475         kfree(interp_params.phdrs);
 476         kfree(interp_params.loadmap);
 477         return retval;
 478 }
 479
 480 /*****************************************************************************/
 481
 482 #ifndef ELF_BASE_PLATFORM
 483 /*
 484  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 485  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 486  * will be copied to the user stack in the same manner as AT_PLATFORM.
 487  */
 488 #define ELF_BASE_PLATFORM NULL
 489 #endif
 490
 491 /*
 492  * present useful information to the program by shovelling it onto the new
 493  * process's stack
 494  */
 495 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 496                                    struct mm_struct *mm,
 497                                    struct elf_fdpic_params *exec_params,
 498                                    struct elf_fdpic_params *interp_params)
 499 {
 500         const struct cred *cred = current_cred();
 501         unsigned long sp, csp, nitems;
 502         elf_caddr_t __user *argv, *envp;
 503         size_t platform_len = 0, len;
 504         char *k_platform, *k_base_platform;
 505         char __user *u_platform, *u_base_platform, *p;
 506         int loop;
 507         int nr; /* reset for each csp adjustment */
 508
 509 #ifdef CONFIG_MMU
 510         /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 511          * by the processes running on the same package. One thing we can do is
 512          * to shuffle the initial stack for them, so we give the architecture
 513          * an opportunity to do so here.
 514          */
 515         sp = arch_align_stack(bprm->p);
 516 #else
 517         sp = mm->start_stack;
 518
 519         /* stack the program arguments and environment */
 520         if (transfer_args_to_stack(bprm, &sp) < 0)
 521                 return -EFAULT;
 522         sp &= ~15;
 523 #endif
 524
 525         /*
 526          * If this architecture has a platform capability string, copy it
 527          * to userspace.  In some cases (Sparc), this info is impossible
 528          * for userspace to get any other way, in others (i386) it is
 529          * merely difficult.
 530          */
 531         k_platform = ELF_PLATFORM;
 532         u_platform = NULL;
 533
 534         if (k_platform) {
 535                 platform_len = strlen(k_platform) + 1;
 536                 sp -= platform_len;
 537                 u_platform = (char __user *) sp;
 538                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 539                         return -EFAULT;
 540         }
 541
 542         /*
 543          * If this architecture has a "base" platform capability
 544          * string, copy it to userspace.
 545          */
 546         k_base_platform = ELF_BASE_PLATFORM;
 547         u_base_platform = NULL;
 548
 549         if (k_base_platform) {
 550                 platform_len = strlen(k_base_platform) + 1;
 551                 sp -= platform_len;
 552                 u_base_platform = (char __user *) sp;
 553                 if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
 554                         return -EFAULT;
 555         }
 556
 557         sp &= ~7UL;
 558
 559         /* stack the load map(s) */
 560         len = sizeof(struct elf32_fdpic_loadmap);
 561         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 562         sp = (sp - len) & ~7UL;
 563         exec_params->map_addr = sp;
 564
 565         if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
 566                 return -EFAULT;
 567
 568         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 569
 570         if (interp_params->loadmap) {
 571                 len = sizeof(struct elf32_fdpic_loadmap);
 572                 len += sizeof(struct elf32_fdpic_loadseg) *
 573                         interp_params->loadmap->nsegs;
 574                 sp = (sp - len) & ~7UL;
 575                 interp_params->map_addr = sp;
 576
 577                 if (copy_to_user((void __user *) sp, interp_params->loadmap,
 578                                  len) != 0)
 579                         return -EFAULT;
 580
 581                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 582         }
 583
 584         /* force 16 byte _final_ alignment here for generality */
 585 #define DLINFO_ITEMS 15
 586
 587         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
 588                 (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
 589
 590         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
 591                 nitems++;
 592
 593         csp = sp;
 594         sp -= nitems * 2 * sizeof(unsigned long);
 595         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 596         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 597         sp -= 1 * sizeof(unsigned long);                /* argc */
 598
 599         csp -= sp & 15UL;
 600         sp -= sp & 15UL;
 601
 602         /* put the ELF interpreter info on the stack */
 603 #define NEW_AUX_ENT(id, val)                                            \
 604         do {                                                            \
 605                 struct { unsigned long _id, _val; } __user *ent;        \
 606                                                                         \
 607                 ent = (void __user *) csp;                              \
 608                 __put_user((id), &ent[nr]._id);                         \
 609                 __put_user((val), &ent[nr]._val);                       \
 610                 nr++;                                                   \
 611         } while (0)
 612
 613         nr = 0;
 614         csp -= 2 * sizeof(unsigned long);
 615         NEW_AUX_ENT(AT_NULL, 0);
 616         if (k_platform) {
 617                 nr = 0;
 618                 csp -= 2 * sizeof(unsigned long);
 619                 NEW_AUX_ENT(AT_PLATFORM,
 620                             (elf_addr_t) (unsigned long) u_platform);
 621         }
 622
 623         if (k_base_platform) {
 624                 nr = 0;
 625                 csp -= 2 * sizeof(unsigned long);
 626                 NEW_AUX_ENT(AT_BASE_PLATFORM,
 627                             (elf_addr_t) (unsigned long) u_base_platform);
 628         }
 629
 630         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
 631                 nr = 0;
 632                 csp -= 2 * sizeof(unsigned long);
 633                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
 634         }
 635
 636         nr = 0;
 637         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 638         NEW_AUX_ENT(AT_HWCAP,   ELF_HWCAP);
 639 #ifdef ELF_HWCAP2
 640         NEW_AUX_ENT(AT_HWCAP2,  ELF_HWCAP2);
 641 #endif
 642         NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
 643         NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
 644         NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
 645         NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
 646         NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
 647         NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
 648         NEW_AUX_ENT(AT_FLAGS,   0);
 649         NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
 650         NEW_AUX_ENT(AT_UID,     (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
 651         NEW_AUX_ENT(AT_EUID,    (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
 652         NEW_AUX_ENT(AT_GID,     (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
 653         NEW_AUX_ENT(AT_EGID,    (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
 654         NEW_AUX_ENT(AT_SECURE,  bprm->secureexec);
 655         NEW_AUX_ENT(AT_EXECFN,  bprm->exec);
 656
 657 #ifdef ARCH_DLINFO
 658         nr = 0;
 659         csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
 660
 661         /* ARCH_DLINFO must come last so platform specific code can enforce
 662          * special alignment requirements on the AUXV if necessary (eg. PPC).
 663          */
 664         ARCH_DLINFO;
 665 #endif
 666 #undef NEW_AUX_ENT
 667
 668         /* allocate room for argv[] and envv[] */
 669         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 670         envp = (elf_caddr_t __user *) csp;
 671         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 672         argv = (elf_caddr_t __user *) csp;
 673
 674         /* stack argc */
 675         csp -= sizeof(unsigned long);
 676         __put_user(bprm->argc, (unsigned long __user *) csp);
 677
 678         BUG_ON(csp != sp);
 679
 680         /* fill in the argv[] array */
 681 #ifdef CONFIG_MMU
 682         current->mm->arg_start = bprm->p;
 683 #else
 684         current->mm->arg_start = current->mm->start_stack -
 685                 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 686 #endif
 687
 688         p = (char __user *) current->mm->arg_start;
 689         for (loop = bprm->argc; loop > 0; loop--) {
 690                 __put_user((elf_caddr_t) p, argv++);
 691                 len = strnlen_user(p, MAX_ARG_STRLEN);
 692                 if (!len || len > MAX_ARG_STRLEN)
 693                         return -EINVAL;
 694                 p += len;
 695         }
 696         __put_user(NULL, argv);
 697         current->mm->arg_end = (unsigned long) p;
 698
 699         /* fill in the envv[] array */
 700         current->mm->env_start = (unsigned long) p;
 701         for (loop = bprm->envc; loop > 0; loop--) {
 702                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
 703                 len = strnlen_user(p, MAX_ARG_STRLEN);
 704                 if (!len || len > MAX_ARG_STRLEN)
 705                         return -EINVAL;
 706                 p += len;
 707         }
 708         __put_user(NULL, envp);
 709         current->mm->env_end = (unsigned long) p;
 710
 711         mm->start_stack = (unsigned long) sp;
 712         return 0;
 713 }
 714
 715 /*****************************************************************************/
 716 /*
 717  * load the appropriate binary image (executable or interpreter) into memory
 718  * - we assume no MMU is available
 719  * - if no other PIC bits are set in params->hdr->e_flags
 720  *   - we assume that the LOADable segments in the binary are independently relocatable
 721  *   - we assume R/O executable segments are shareable
 722  * - else
 723  *   - we assume the loadable parts of the image to require fixed displacement
 724  *   - the image is not shareable
 725  */
 726 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 727                               struct file *file,
 728                               struct mm_struct *mm,
 729                               const char *what)
 730 {
 731         struct elf32_fdpic_loadmap *loadmap;
 732 #ifdef CONFIG_MMU
 733         struct elf32_fdpic_loadseg *mseg;
 734 #endif
 735         struct elf32_fdpic_loadseg *seg;
 736         struct elf32_phdr *phdr;
 737         unsigned long load_addr, stop;
 738         unsigned nloads, tmp;
 739         size_t size;
 740         int loop, ret;
 741
 742         /* allocate a load map table */
 743         nloads = 0;
 744         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 745                 if (params->phdrs[loop].p_type == PT_LOAD)
 746                         nloads++;
 747
 748         if (nloads == 0)
 749                 return -ELIBBAD;
 750
 751         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 752         loadmap = kzalloc(size, GFP_KERNEL);
 753         if (!loadmap)
 754                 return -ENOMEM;
 755
 756         params->loadmap = loadmap;
 757
 758         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 759         loadmap->nsegs = nloads;
 760
 761         load_addr = params->load_addr;
 762         seg = loadmap->segs;
 763
 764         /* map the requested LOADs into the memory space */
 765         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 766         case ELF_FDPIC_FLAG_CONSTDISP:
 767         case ELF_FDPIC_FLAG_CONTIGUOUS:
 768 #ifndef CONFIG_MMU
 769                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 770                 if (ret < 0)
 771                         return ret;
 772                 break;
 773 #endif
 774         default:
 775                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 776                 if (ret < 0)
 777                         return ret;
 778                 break;
 779         }
 780
 781         /* map the entry point */
 782         if (params->hdr.e_entry) {
 783                 seg = loadmap->segs;
 784                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 785                         if (params->hdr.e_entry >= seg->p_vaddr &&
 786                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
 787                                 params->entry_addr =
 788                                         (params->hdr.e_entry - seg->p_vaddr) +
 789                                         seg->addr;
 790                                 break;
 791                         }
 792                 }
 793         }
 794
 795         /* determine where the program header table has wound up if mapped */
 796         stop = params->hdr.e_phoff;
 797         stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
 798         phdr = params->phdrs;
 799
 800         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 801                 if (phdr->p_type != PT_LOAD)
 802                         continue;
 803
 804                 if (phdr->p_offset > params->hdr.e_phoff ||
 805                     phdr->p_offset + phdr->p_filesz < stop)
 806                         continue;
 807
 808                 seg = loadmap->segs;
 809                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 810                         if (phdr->p_vaddr >= seg->p_vaddr &&
 811                             phdr->p_vaddr + phdr->p_filesz <=
 812                             seg->p_vaddr + seg->p_memsz) {
 813                                 params->ph_addr =
 814                                         (phdr->p_vaddr - seg->p_vaddr) +
 815                                         seg->addr +
 816                                         params->hdr.e_phoff - phdr->p_offset;
 817                                 break;
 818                         }
 819                 }
 820                 break;
 821         }
 822
 823         /* determine where the dynamic section has wound up if there is one */
 824         phdr = params->phdrs;
 825         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 826                 if (phdr->p_type != PT_DYNAMIC)
 827                         continue;
 828
 829                 seg = loadmap->segs;
 830                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 831                         if (phdr->p_vaddr >= seg->p_vaddr &&
 832                             phdr->p_vaddr + phdr->p_memsz <=
 833                             seg->p_vaddr + seg->p_memsz) {
 834                                 params->dynamic_addr =
 835                                         (phdr->p_vaddr - seg->p_vaddr) +
 836                                         seg->addr;
 837
 838                                 /* check the dynamic section contains at least
 839                                  * one item, and that the last item is a NULL
 840                                  * entry */
 841                                 if (phdr->p_memsz == 0 ||
 842                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 843                                         goto dynamic_error;
 844
 845                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 846                                 if (((Elf32_Dyn *)
 847                                      params->dynamic_addr)[tmp - 1].d_tag != 0)
 848                                         goto dynamic_error;
 849                                 break;
 850                         }
 851                 }
 852                 break;
 853         }
 854
 855         /* now elide adjacent segments in the load map on MMU linux
 856          * - on uClinux the holes between may actually be filled with system
 857          *   stuff or stuff from other processes
 858          */
 859 #ifdef CONFIG_MMU
 860         nloads = loadmap->nsegs;
 861         mseg = loadmap->segs;
 862         seg = mseg + 1;
 863         for (loop = 1; loop < nloads; loop++) {
 864                 /* see if we have a candidate for merging */
 865                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 866                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 867                         if (load_addr == (seg->addr & PAGE_MASK)) {
 868                                 mseg->p_memsz +=
 869                                         load_addr -
 870                                         (mseg->addr + mseg->p_memsz);
 871                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 872                                 mseg->p_memsz += seg->p_memsz;
 873                                 loadmap->nsegs--;
 874                                 continue;
 875                         }
 876                 }
 877
 878                 mseg++;
 879                 if (mseg != seg)
 880                         *mseg = *seg;
 881         }
 882 #endif
 883
 884         kdebug("Mapped Object [%s]:", what);
 885         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 886         kdebug("- entry    : %lx", params->entry_addr);
 887         kdebug("- PHDR[]   : %lx", params->ph_addr);
 888         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 889         seg = loadmap->segs;
 890         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 891                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 892                        loop,
 893                        seg->addr, seg->addr + seg->p_memsz - 1,
 894                        seg->p_vaddr, seg->p_memsz);
 895
 896         return 0;
 897
 898 dynamic_error:
 899         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 900                what, file_inode(file)->i_ino);
 901         return -ELIBBAD;
 902 }
 903
 904 /*****************************************************************************/
 905 /*
 906  * map a file with constant displacement under uClinux
 907  */
 908 #ifndef CONFIG_MMU
 909 static int elf_fdpic_map_file_constdisp_on_uclinux(
 910         struct elf_fdpic_params *params,
 911         struct file *file,
 912         struct mm_struct *mm)
 913 {
 914         struct elf32_fdpic_loadseg *seg;
 915         struct elf32_phdr *phdr;
 916         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 917         int loop, ret;
 918
 919         load_addr = params->load_addr;
 920         seg = params->loadmap->segs;
 921
 922         /* determine the bounds of the contiguous overall allocation we must
 923          * make */
 924         phdr = params->phdrs;
 925         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 926                 if (params->phdrs[loop].p_type != PT_LOAD)
 927                         continue;
 928
 929                 if (base > phdr->p_vaddr)
 930                         base = phdr->p_vaddr;
 931                 if (top < phdr->p_vaddr + phdr->p_memsz)
 932                         top = phdr->p_vaddr + phdr->p_memsz;
 933         }
 934
 935         /* allocate one big anon block for everything */
 936         mflags = MAP_PRIVATE;
 937         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 938                 mflags |= MAP_EXECUTABLE;
 939
 940         maddr = vm_mmap(NULL, load_addr, top - base,
 941                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 942         if (IS_ERR_VALUE(maddr))
 943                 return (int) maddr;
 944
 945         if (load_addr != 0)
 946                 load_addr += PAGE_ALIGN(top - base);
 947
 948         /* and then load the file segments into it */
 949         phdr = params->phdrs;
 950         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 951                 if (params->phdrs[loop].p_type != PT_LOAD)
 952                         continue;
 953
 954                 seg->addr = maddr + (phdr->p_vaddr - base);
 955                 seg->p_vaddr = phdr->p_vaddr;
 956                 seg->p_memsz = phdr->p_memsz;
 957
 958                 ret = read_code(file, seg->addr, phdr->p_offset,
 959                                        phdr->p_filesz);
 960                 if (ret < 0)
 961                         return ret;
 962
 963                 /* map the ELF header address if in this segment */
 964                 if (phdr->p_offset == 0)
 965                         params->elfhdr_addr = seg->addr;
 966
 967                 /* clear any space allocated but not loaded */
 968                 if (phdr->p_filesz < phdr->p_memsz) {
 969                         if (clear_user((void *) (seg->addr + phdr->p_filesz),
 970                                        phdr->p_memsz - phdr->p_filesz))
 971                                 return -EFAULT;
 972                 }
 973
 974                 if (mm) {
 975                         if (phdr->p_flags & PF_X) {
 976                                 if (!mm->start_code) {
 977                                         mm->start_code = seg->addr;
 978                                         mm->end_code = seg->addr +
 979                                                 phdr->p_memsz;
 980                                 }
 981                         } else if (!mm->start_data) {
 982                                 mm->start_data = seg->addr;
 983                                 mm->end_data = seg->addr + phdr->p_memsz;
 984                         }
 985                 }
 986
 987                 seg++;
 988         }
 989
 990         return 0;
 991 }
 992 #endif
 993
 994 /*****************************************************************************/
 995 /*
 996  * map a binary by direct mmap() of the individual PT_LOAD segments
 997  */
 998 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 999                                              struct file *file,
1000                                              struct mm_struct *mm)
1001 {
1002         struct elf32_fdpic_loadseg *seg;
1003         struct elf32_phdr *phdr;
1004         unsigned long load_addr, delta_vaddr;
1005         int loop, dvset;
1006
1007         load_addr = params->load_addr;
1008         delta_vaddr = 0;
1009         dvset = 0;
1010
1011         seg = params->loadmap->segs;
1012
1013         /* deal with each load segment separately */
1014         phdr = params->phdrs;
1015         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1016                 unsigned long maddr, disp, excess, excess1;
1017                 int prot = 0, flags;
1018
1019                 if (phdr->p_type != PT_LOAD)
1020                         continue;
1021
1022                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1023                        (unsigned long) phdr->p_vaddr,
1024                        (unsigned long) phdr->p_offset,
1025                        (unsigned long) phdr->p_filesz,
1026                        (unsigned long) phdr->p_memsz);
1027
1028                 /* determine the mapping parameters */
1029                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
1030                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1031                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1032
1033                 flags = MAP_PRIVATE | MAP_DENYWRITE;
1034                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
1035                         flags |= MAP_EXECUTABLE;
1036
1037                 maddr = 0;
1038
1039                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1040                 case ELF_FDPIC_FLAG_INDEPENDENT:
1041                         /* PT_LOADs are independently locatable */
1042                         break;
1043
1044                 case ELF_FDPIC_FLAG_HONOURVADDR:
1045                         /* the specified virtual address must be honoured */
1046                         maddr = phdr->p_vaddr;
1047                         flags |= MAP_FIXED;
1048                         break;
1049
1050                 case ELF_FDPIC_FLAG_CONSTDISP:
1051                         /* constant displacement
1052                          * - can be mapped anywhere, but must be mapped as a
1053                          *   unit
1054                          */
1055                         if (!dvset) {
1056                                 maddr = load_addr;
1057                                 delta_vaddr = phdr->p_vaddr;
1058                                 dvset = 1;
1059                         } else {
1060                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1061                                 flags |= MAP_FIXED;
1062                         }
1063                         break;
1064
1065                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1066                         /* contiguity handled later */
1067                         break;
1068
1069                 default:
1070                         BUG();
1071                 }
1072
1073                 maddr &= PAGE_MASK;
1074
1075                 /* create the mapping */
1076                 disp = phdr->p_vaddr & ~PAGE_MASK;
1077                 maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1078                                 phdr->p_offset - disp);
1079
1080                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1081                        loop, phdr->p_memsz + disp, prot, flags,
1082                        phdr->p_offset - disp, maddr);
1083
1084                 if (IS_ERR_VALUE(maddr))
1085                         return (int) maddr;
1086
1087                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1088                     ELF_FDPIC_FLAG_CONTIGUOUS)
1089                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1090
1091                 seg->addr = maddr + disp;
1092                 seg->p_vaddr = phdr->p_vaddr;
1093                 seg->p_memsz = phdr->p_memsz;
1094
1095                 /* map the ELF header address if in this segment */
1096                 if (phdr->p_offset == 0)
1097                         params->elfhdr_addr = seg->addr;
1098
1099                 /* clear the bit between beginning of mapping and beginning of
1100                  * PT_LOAD */
1101                 if (prot & PROT_WRITE && disp > 0) {
1102                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1103                         if (clear_user((void __user *) maddr, disp))
1104                                 return -EFAULT;
1105                         maddr += disp;
1106                 }
1107
1108                 /* clear any space allocated but not loaded
1109                  * - on uClinux we can just clear the lot
1110                  * - on MMU linux we'll get a SIGBUS beyond the last page
1111                  *   extant in the file
1112                  */
1113                 excess = phdr->p_memsz - phdr->p_filesz;
1114                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1115
1116 #ifdef CONFIG_MMU
1117                 if (excess > excess1) {
1118                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1119                         unsigned long xmaddr;
1120
1121                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1122                         xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
1123                                          prot, flags, 0);
1124
1125                         kdebug("mmap[%d] <anon>"
1126                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1127                                loop, xaddr, excess - excess1, prot, flags,
1128                                xmaddr);
1129
1130                         if (xmaddr != xaddr)
1131                                 return -ENOMEM;
1132                 }
1133
1134                 if (prot & PROT_WRITE && excess1 > 0) {
1135                         kdebug("clear[%d] ad=%lx sz=%lx",
1136                                loop, maddr + phdr->p_filesz, excess1);
1137                         if (clear_user((void __user *) maddr + phdr->p_filesz,
1138                                        excess1))
1139                                 return -EFAULT;
1140                 }
1141
1142 #else
1143                 if (excess > 0) {
1144                         kdebug("clear[%d] ad=%lx sz=%lx",
1145                                loop, maddr + phdr->p_filesz, excess);
1146                         if (clear_user((void *) maddr + phdr->p_filesz, excess))
1147                                 return -EFAULT;
1148                 }
1149 #endif
1150
1151                 if (mm) {
1152                         if (phdr->p_flags & PF_X) {
1153                                 if (!mm->start_code) {
1154                                         mm->start_code = maddr;
1155                                         mm->end_code = maddr + phdr->p_memsz;
1156                                 }
1157                         } else if (!mm->start_data) {
1158                                 mm->start_data = maddr;
1159                                 mm->end_data = maddr + phdr->p_memsz;
1160                         }
1161                 }
1162
1163                 seg++;
1164         }
1165
1166         return 0;
1167 }
1168
1169 /*****************************************************************************/
1170 /*
1171  * ELF-FDPIC core dumper
1172  *
1173  * Modelled on fs/exec.c:aout_core_dump()
1174  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1175  *
1176  * Modelled on fs/binfmt_elf.c core dumper
1177  */
1178 #ifdef CONFIG_ELF_CORE
1179
1180 /*
1181  * Decide whether a segment is worth dumping; default is yes to be
1182  * sure (missing info is worse than too much; etc).
1183  * Personally I'd include everything, and use the coredump limit...
1184  *
1185  * I think we should skip something. But I am not sure how. H.J.
1186  */
1187 static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
1188 {
1189         int dump_ok;
1190
1191         /* Do not dump I/O mapped devices or special mappings */
1192         if (vma->vm_flags & VM_IO) {
1193                 kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
1194                 return 0;
1195         }
1196
1197         /* If we may not read the contents, don't allow us to dump
1198          * them either. "dump_write()" can't handle it anyway.
1199          */
1200         if (!(vma->vm_flags & VM_READ)) {
1201                 kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
1202                 return 0;
1203         }
1204
1205         /* support for DAX */
1206         if (vma_is_dax(vma)) {
1207                 if (vma->vm_flags & VM_SHARED) {
1208                         dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
1209                         kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
1210                                vma->vm_flags, dump_ok ? "yes" : "no");
1211                 } else {
1212                         dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
1213                         kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
1214                                vma->vm_flags, dump_ok ? "yes" : "no");
1215                 }
1216                 return dump_ok;
1217         }
1218
1219         /* By default, dump shared memory if mapped from an anonymous file. */
1220         if (vma->vm_flags & VM_SHARED) {
1221                 if (file_inode(vma->vm_file)->i_nlink == 0) {
1222                         dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
1223                         kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1224                                vma->vm_flags, dump_ok ? "yes" : "no");
1225                         return dump_ok;
1226                 }
1227
1228                 dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
1229                 kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1230                        vma->vm_flags, dump_ok ? "yes" : "no");
1231                 return dump_ok;
1232         }
1233
1234 #ifdef CONFIG_MMU
1235         /* By default, if it hasn't been written to, don't write it out */
1236         if (!vma->anon_vma) {
1237                 dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
1238                 kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
1239                        vma->vm_flags, dump_ok ? "yes" : "no");
1240                 return dump_ok;
1241         }
1242 #endif
1243
1244         dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
1245         kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
1246                dump_ok ? "yes" : "no");
1247         return dump_ok;
1248 }
1249
1250 /* An ELF note in memory */
1251 struct memelfnote
1252 {
1253         const char *name;
1254         int type;
1255         unsigned int datasz;
1256         void *data;
1257 };
1258
1259 static int notesize(struct memelfnote *en)
1260 {
1261         int sz;
1262
1263         sz = sizeof(struct elf_note);
1264         sz += roundup(strlen(en->name) + 1, 4);
1265         sz += roundup(en->datasz, 4);
1266
1267         return sz;
1268 }
1269
1270 /* #define DEBUG */
1271
1272 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1273 {
1274         struct elf_note en;
1275         en.n_namesz = strlen(men->name) + 1;
1276         en.n_descsz = men->datasz;
1277         en.n_type = men->type;
1278
1279         return dump_emit(cprm, &en, sizeof(en)) &&
1280                 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1281                 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1282 }
1283
1284 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1285 {
1286         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1287         elf->e_ident[EI_CLASS] = ELF_CLASS;
1288         elf->e_ident[EI_DATA] = ELF_DATA;
1289         elf->e_ident[EI_VERSION] = EV_CURRENT;
1290         elf->e_ident[EI_OSABI] = ELF_OSABI;
1291         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1292
1293         elf->e_type = ET_CORE;
1294         elf->e_machine = ELF_ARCH;
1295         elf->e_version = EV_CURRENT;
1296         elf->e_entry = 0;
1297         elf->e_phoff = sizeof(struct elfhdr);
1298         elf->e_shoff = 0;
1299         elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1300         elf->e_ehsize = sizeof(struct elfhdr);
1301         elf->e_phentsize = sizeof(struct elf_phdr);
1302         elf->e_phnum = segs;
1303         elf->e_shentsize = 0;
1304         elf->e_shnum = 0;
1305         elf->e_shstrndx = 0;
1306         return;
1307 }
1308
1309 static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1310 {
1311         phdr->p_type = PT_NOTE;
1312         phdr->p_offset = offset;
1313         phdr->p_vaddr = 0;
1314         phdr->p_paddr = 0;
1315         phdr->p_filesz = sz;
1316         phdr->p_memsz = 0;
1317         phdr->p_flags = 0;
1318         phdr->p_align = 0;
1319         return;
1320 }
1321
1322 static inline void fill_note(struct memelfnote *note, const char *name, int type,
1323                 unsigned int sz, void *data)
1324 {
1325         note->name = name;
1326         note->type = type;
1327         note->datasz = sz;
1328         note->data = data;
1329         return;
1330 }
1331
1332 /*
1333  * fill up all the fields in prstatus from the given task struct, except
1334  * registers which need to be filled up separately.
1335  */
1336 static void fill_prstatus(struct elf_prstatus *prstatus,
1337                           struct task_struct *p, long signr)
1338 {
1339         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1340         prstatus->pr_sigpend = p->pending.signal.sig[0];
1341         prstatus->pr_sighold = p->blocked.sig[0];
1342         rcu_read_lock();
1343         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1344         rcu_read_unlock();
1345         prstatus->pr_pid = task_pid_vnr(p);
1346         prstatus->pr_pgrp = task_pgrp_vnr(p);
1347         prstatus->pr_sid = task_session_vnr(p);
1348         if (thread_group_leader(p)) {
1349                 struct task_cputime cputime;
1350
1351                 /*
1352                  * This is the record for the group leader.  It shows the
1353                  * group-wide total, not its individual thread total.
1354                  */
1355                 thread_group_cputime(p, &cputime);
1356                 prstatus->pr_utime = ns_to_timeval(cputime.utime);
1357                 prstatus->pr_stime = ns_to_timeval(cputime.stime);
1358         } else {
1359                 u64 utime, stime;
1360
1361                 task_cputime(p, &utime, &stime);
1362                 prstatus->pr_utime = ns_to_timeval(utime);
1363                 prstatus->pr_stime = ns_to_timeval(stime);
1364         }
1365         prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
1366         prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
1367
1368         prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1369         prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1370 }
1371
1372 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1373                        struct mm_struct *mm)
1374 {
1375         const struct cred *cred;
1376         unsigned int i, len;
1377
1378         /* first copy the parameters from user space */
1379         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1380
1381         len = mm->arg_end - mm->arg_start;
1382         if (len >= ELF_PRARGSZ)
1383                 len = ELF_PRARGSZ - 1;
1384         if (copy_from_user(&psinfo->pr_psargs,
1385                            (const char __user *) mm->arg_start, len))
1386                 return -EFAULT;
1387         for (i = 0; i < len; i++)
1388                 if (psinfo->pr_psargs[i] == 0)
1389                         psinfo->pr_psargs[i] = ' ';
1390         psinfo->pr_psargs[len] = 0;
1391
1392         rcu_read_lock();
1393         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1394         rcu_read_unlock();
1395         psinfo->pr_pid = task_pid_vnr(p);
1396         psinfo->pr_pgrp = task_pgrp_vnr(p);
1397         psinfo->pr_sid = task_session_vnr(p);
1398
1399         i = p->state ? ffz(~p->state) + 1 : 0;
1400         psinfo->pr_state = i;
1401         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1402         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1403         psinfo->pr_nice = task_nice(p);
1404         psinfo->pr_flag = p->flags;
1405         rcu_read_lock();
1406         cred = __task_cred(p);
1407         SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1408         SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1409         rcu_read_unlock();
1410         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1411
1412         return 0;
1413 }
1414
1415 /* Here is the structure in which status of each thread is captured. */
1416 struct elf_thread_status
1417 {
1418         struct list_head list;
1419         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1420         elf_fpregset_t fpu;             /* NT_PRFPREG */
1421         struct task_struct *thread;
1422 #ifdef ELF_CORE_COPY_XFPREGS
1423         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1424 #endif
1425         struct memelfnote notes[3];
1426         int num_notes;
1427 };
1428
1429 /*
1430  * In order to add the specific thread information for the elf file format,
1431  * we need to keep a linked list of every thread's pr_status and then create
1432  * a single section for them in the final core file.
1433  */
1434 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1435 {
1436         struct task_struct *p = t->thread;
1437         int sz = 0;
1438
1439         t->num_notes = 0;
1440
1441         fill_prstatus(&t->prstatus, p, signr);
1442         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1443
1444         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1445                   &t->prstatus);
1446         t->num_notes++;
1447         sz += notesize(&t->notes[0]);
1448
1449         t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
1450         if (t->prstatus.pr_fpvalid) {
1451                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1452                           &t->fpu);
1453                 t->num_notes++;
1454                 sz += notesize(&t->notes[1]);
1455         }
1456
1457 #ifdef ELF_CORE_COPY_XFPREGS
1458         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1459                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1460                           sizeof(t->xfpu), &t->xfpu);
1461                 t->num_notes++;
1462                 sz += notesize(&t->notes[2]);
1463         }
1464 #endif
1465         return sz;
1466 }
1467
1468 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1469                              elf_addr_t e_shoff, int segs)
1470 {
1471         elf->e_shoff = e_shoff;
1472         elf->e_shentsize = sizeof(*shdr4extnum);
1473         elf->e_shnum = 1;
1474         elf->e_shstrndx = SHN_UNDEF;
1475
1476         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1477
1478         shdr4extnum->sh_type = SHT_NULL;
1479         shdr4extnum->sh_size = elf->e_shnum;
1480         shdr4extnum->sh_link = elf->e_shstrndx;
1481         shdr4extnum->sh_info = segs;
1482 }
1483
1484 /*
1485  * dump the segments for an MMU process
1486  */
1487 static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
1488 {
1489         struct vm_area_struct *vma;
1490
1491         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1492                 unsigned long addr;
1493
1494                 if (!maydump(vma, cprm->mm_flags))
1495                         continue;
1496
1497 #ifdef CONFIG_MMU
1498                 for (addr = vma->vm_start; addr < vma->vm_end;
1499                                                         addr += PAGE_SIZE) {
1500                         bool res;
1501                         struct page *page = get_dump_page(addr);
1502                         if (page) {
1503                                 void *kaddr = kmap(page);
1504                                 res = dump_emit(cprm, kaddr, PAGE_SIZE);
1505                                 kunmap(page);
1506                                 put_page(page);
1507                         } else {
1508                                 res = dump_skip(cprm, PAGE_SIZE);
1509                         }
1510                         if (!res)
1511                                 return false;
1512                 }
1513 #else
1514                 if (!dump_emit(cprm, (void *) vma->vm_start,
1515                                 vma->vm_end - vma->vm_start))
1516                         return false;
1517 #endif
1518         }
1519         return true;
1520 }
1521
1522 static size_t elf_core_vma_data_size(unsigned long mm_flags)
1523 {
1524         struct vm_area_struct *vma;
1525         size_t size = 0;
1526
1527         for (vma = current->mm->mmap; vma; vma = vma->vm_next)
1528                 if (maydump(vma, mm_flags))
1529                         size += vma->vm_end - vma->vm_start;
1530         return size;
1531 }
1532
1533 /*
1534  * Actual dumper
1535  *
1536  * This is a two-pass process; first we find the offsets of the bits,
1537  * and then they are actually written out.  If we run out of core limit
1538  * we just truncate.
1539  */
1540 static int elf_fdpic_core_dump(struct coredump_params *cprm)
1541 {
1542 #define NUM_NOTES       6
1543         int has_dumped = 0;
1544         mm_segment_t fs;
1545         int segs;
1546         int i;
1547         struct vm_area_struct *vma;
1548         struct elfhdr *elf = NULL;
1549         loff_t offset = 0, dataoff;
1550         int numnote;
1551         struct memelfnote *notes = NULL;
1552         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
1553         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
1554         LIST_HEAD(thread_list);
1555         struct list_head *t;
1556         elf_fpregset_t *fpu = NULL;
1557 #ifdef ELF_CORE_COPY_XFPREGS
1558         elf_fpxregset_t *xfpu = NULL;
1559 #endif
1560         int thread_status_size = 0;
1561         elf_addr_t *auxv;
1562         struct elf_phdr *phdr4note = NULL;
1563         struct elf_shdr *shdr4extnum = NULL;
1564         Elf_Half e_phnum;
1565         elf_addr_t e_shoff;
1566         struct core_thread *ct;
1567         struct elf_thread_status *tmp;
1568
1569         /*
1570          * We no longer stop all VM operations.
1571          *
1572          * This is because those proceses that could possibly change map_count
1573          * or the mmap / vma pages are now blocked in do_exit on current
1574          * finishing this core dump.
1575          *
1576          * Only ptrace can touch these memory addresses, but it doesn't change
1577          * the map_count or the pages allocated. So no possibility of crashing
1578          * exists while dumping the mm->vm_next areas to the core file.
1579          */
1580
1581         /* alloc memory for large data structures: too large to be on stack */
1582         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1583         if (!elf)
1584                 goto cleanup;
1585         prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
1586         if (!prstatus)
1587                 goto cleanup;
1588         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1589         if (!psinfo)
1590                 goto cleanup;
1591         notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
1592         if (!notes)
1593                 goto cleanup;
1594         fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1595         if (!fpu)
1596                 goto cleanup;
1597 #ifdef ELF_CORE_COPY_XFPREGS
1598         xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1599         if (!xfpu)
1600                 goto cleanup;
1601 #endif
1602
1603         for (ct = current->mm->core_state->dumper.next;
1604                                         ct; ct = ct->next) {
1605                 tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
1606                 if (!tmp)
1607                         goto cleanup;
1608
1609                 tmp->thread = ct->task;
1610                 list_add(&tmp->list, &thread_list);
1611         }
1612
1613         list_for_each(t, &thread_list) {
1614                 struct elf_thread_status *tmp;
1615                 int sz;
1616
1617                 tmp = list_entry(t, struct elf_thread_status, list);
1618                 sz = elf_dump_thread_status(cprm->siginfo->si_signo, tmp);
1619                 thread_status_size += sz;
1620         }
1621
1622         /* now collect the dump for the current */
1623         fill_prstatus(prstatus, current, cprm->siginfo->si_signo);
1624         elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
1625
1626         segs = current->mm->map_count;
1627         segs += elf_core_extra_phdrs();
1628
1629         /* for notes section */
1630         segs++;
1631
1632         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1633          * this, kernel supports extended numbering. Have a look at
1634          * include/linux/elf.h for further information. */
1635         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1636
1637         /* Set up header */
1638         fill_elf_fdpic_header(elf, e_phnum);
1639
1640         has_dumped = 1;
1641         /*
1642          * Set up the notes in similar form to SVR4 core dumps made
1643          * with info from their /proc.
1644          */
1645
1646         fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1647         fill_psinfo(psinfo, current->group_leader, current->mm);
1648         fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1649
1650         numnote = 2;
1651
1652         auxv = (elf_addr_t *) current->mm->saved_auxv;
1653
1654         i = 0;
1655         do
1656                 i += 2;
1657         while (auxv[i - 2] != AT_NULL);
1658         fill_note(&notes[numnote++], "CORE", NT_AUXV,
1659                   i * sizeof(elf_addr_t), auxv);
1660
1661         /* Try to dump the FPU. */
1662         if ((prstatus->pr_fpvalid =
1663              elf_core_copy_task_fpregs(current, cprm->regs, fpu)))
1664                 fill_note(notes + numnote++,
1665                           "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1666 #ifdef ELF_CORE_COPY_XFPREGS
1667         if (elf_core_copy_task_xfpregs(current, xfpu))
1668                 fill_note(notes + numnote++,
1669                           "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
1670 #endif
1671
1672         fs = get_fs();
1673         set_fs(KERNEL_DS);
1674
1675         offset += sizeof(*elf);                         /* Elf header */
1676         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
1677
1678         /* Write notes phdr entry */
1679         {
1680                 int sz = 0;
1681
1682                 for (i = 0; i < numnote; i++)
1683                         sz += notesize(notes + i);
1684
1685                 sz += thread_status_size;
1686
1687                 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1688                 if (!phdr4note)
1689                         goto end_coredump;
1690
1691                 fill_elf_note_phdr(phdr4note, sz, offset);
1692                 offset += sz;
1693         }
1694
1695         /* Page-align dumped data */
1696         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1697
1698         offset += elf_core_vma_data_size(cprm->mm_flags);
1699         offset += elf_core_extra_data_size();
1700         e_shoff = offset;
1701
1702         if (e_phnum == PN_XNUM) {
1703                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1704                 if (!shdr4extnum)
1705                         goto end_coredump;
1706                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1707         }
1708
1709         offset = dataoff;
1710
1711         if (!dump_emit(cprm, elf, sizeof(*elf)))
1712                 goto end_coredump;
1713
1714         if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
1715                 goto end_coredump;
1716
1717         /* write program headers for segments dump */
1718         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1719                 struct elf_phdr phdr;
1720                 size_t sz;
1721
1722                 sz = vma->vm_end - vma->vm_start;
1723
1724                 phdr.p_type = PT_LOAD;
1725                 phdr.p_offset = offset;
1726                 phdr.p_vaddr = vma->vm_start;
1727                 phdr.p_paddr = 0;
1728                 phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
1729                 phdr.p_memsz = sz;
1730                 offset += phdr.p_filesz;
1731                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1732                 if (vma->vm_flags & VM_WRITE)
1733                         phdr.p_flags |= PF_W;
1734                 if (vma->vm_flags & VM_EXEC)
1735                         phdr.p_flags |= PF_X;
1736                 phdr.p_align = ELF_EXEC_PAGESIZE;
1737
1738                 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
1739                         goto end_coredump;
1740         }
1741
1742         if (!elf_core_write_extra_phdrs(cprm, offset))
1743                 goto end_coredump;
1744
1745         /* write out the notes section */
1746         for (i = 0; i < numnote; i++)
1747                 if (!writenote(notes + i, cprm))
1748                         goto end_coredump;
1749
1750         /* write out the thread status notes section */
1751         list_for_each(t, &thread_list) {
1752                 struct elf_thread_status *tmp =
1753                                 list_entry(t, struct elf_thread_status, list);
1754
1755                 for (i = 0; i < tmp->num_notes; i++)
1756                         if (!writenote(&tmp->notes[i], cprm))
1757                                 goto end_coredump;
1758         }
1759
1760         if (!dump_skip(cprm, dataoff - cprm->pos))
1761                 goto end_coredump;
1762
1763         if (!elf_fdpic_dump_segments(cprm))
1764                 goto end_coredump;
1765
1766         if (!elf_core_write_extra_data(cprm))
1767                 goto end_coredump;
1768
1769         if (e_phnum == PN_XNUM) {
1770                 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
1771                         goto end_coredump;
1772         }
1773
1774         if (cprm->file->f_pos != offset) {
1775                 /* Sanity check */
1776                 printk(KERN_WARNING
1777                        "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1778                        cprm->file->f_pos, offset);
1779         }
1780
1781 end_coredump:
1782         set_fs(fs);
1783
1784 cleanup:
1785         while (!list_empty(&thread_list)) {
1786                 struct list_head *tmp = thread_list.next;
1787                 list_del(tmp);
1788                 kfree(list_entry(tmp, struct elf_thread_status, list));
1789         }
1790         kfree(phdr4note);
1791         kfree(elf);
1792         kfree(prstatus);
1793         kfree(psinfo);
1794         kfree(notes);
1795         kfree(fpu);
1796         kfree(shdr4extnum);
1797 #ifdef ELF_CORE_COPY_XFPREGS
1798         kfree(xfpu);
1799 #endif
1800         return has_dumped;
1801 #undef NUM_NOTES
1802 }
1803
1804 #endif          /* CONFIG_ELF_CORE */