fs/binfmt_elf_fdpic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* binfmt_elf_fdpic.c: FDPIC ELF binary format
   3  *
   4  * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  * Derived from binfmt_elf.c
   7  */
   8
   9 #include <linux/module.h>
  10
  11 #include <linux/fs.h>
  12 #include <linux/stat.h>
  13 #include <linux/sched.h>
  14 #include <linux/sched/coredump.h>
  15 #include <linux/sched/task_stack.h>
  16 #include <linux/sched/cputime.h>
  17 #include <linux/mm.h>
  18 #include <linux/mman.h>
  19 #include <linux/errno.h>
  20 #include <linux/signal.h>
  21 #include <linux/binfmts.h>
  22 #include <linux/string.h>
  23 #include <linux/file.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/slab.h>
  26 #include <linux/pagemap.h>
  27 #include <linux/security.h>
  28 #include <linux/highmem.h>
  29 #include <linux/highuid.h>
  30 #include <linux/personality.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/init.h>
  33 #include <linux/elf.h>
  34 #include <linux/elf-fdpic.h>
  35 #include <linux/elfcore.h>
  36 #include <linux/coredump.h>
  37 #include <linux/dax.h>
  38
  39 #include <linux/uaccess.h>
  40 #include <asm/param.h>
  41 #include <asm/pgalloc.h>
  42
  43 typedef char *elf_caddr_t;
  44
  45 #if 0
  46 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  47 #else
  48 #define kdebug(fmt, ...) do {} while(0)
  49 #endif
  50
  51 #if 0
  52 #define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
  53 #else
  54 #define kdcore(fmt, ...) do {} while(0)
  55 #endif
  56
  57 MODULE_LICENSE("GPL");
  58
  59 static int load_elf_fdpic_binary(struct linux_binprm *);
  60 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
  61 static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
  62                               struct mm_struct *, const char *);
  63
  64 static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
  65                                    struct elf_fdpic_params *,
  66                                    struct elf_fdpic_params *);
  67
  68 #ifndef CONFIG_MMU
  69 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
  70                                                    struct file *,
  71                                                    struct mm_struct *);
  72 #endif
  73
  74 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
  75                                              struct file *, struct mm_struct *);
  76
  77 #ifdef CONFIG_ELF_CORE
  78 static int elf_fdpic_core_dump(struct coredump_params *cprm);
  79 #endif
  80
  81 static struct linux_binfmt elf_fdpic_format = {
  82         .module         = THIS_MODULE,
  83         .load_binary    = load_elf_fdpic_binary,
  84 #ifdef CONFIG_ELF_CORE
  85         .core_dump      = elf_fdpic_core_dump,
  86 #endif
  87         .min_coredump   = ELF_EXEC_PAGESIZE,
  88 };
  89
  90 static int __init init_elf_fdpic_binfmt(void)
  91 {
  92         register_binfmt(&elf_fdpic_format);
  93         return 0;
  94 }
  95
  96 static void __exit exit_elf_fdpic_binfmt(void)
  97 {
  98         unregister_binfmt(&elf_fdpic_format);
  99 }
 100
 101 core_initcall(init_elf_fdpic_binfmt);
 102 module_exit(exit_elf_fdpic_binfmt);
 103
 104 static int is_elf(struct elfhdr *hdr, struct file *file)
 105 {
 106         if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
 107                 return 0;
 108         if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
 109                 return 0;
 110         if (!elf_check_arch(hdr))
 111                 return 0;
 112         if (!file->f_op->mmap)
 113                 return 0;
 114         return 1;
 115 }
 116
 117 #ifndef elf_check_fdpic
 118 #define elf_check_fdpic(x) 0
 119 #endif
 120
 121 #ifndef elf_check_const_displacement
 122 #define elf_check_const_displacement(x) 0
 123 #endif
 124
 125 static int is_constdisp(struct elfhdr *hdr)
 126 {
 127         if (!elf_check_fdpic(hdr))
 128                 return 1;
 129         if (elf_check_const_displacement(hdr))
 130                 return 1;
 131         return 0;
 132 }
 133
 134 /*****************************************************************************/
 135 /*
 136  * read the program headers table into memory
 137  */
 138 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
 139                                  struct file *file)
 140 {
 141         struct elf32_phdr *phdr;
 142         unsigned long size;
 143         int retval, loop;
 144         loff_t pos = params->hdr.e_phoff;
 145
 146         if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 147                 return -ENOMEM;
 148         if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
 149                 return -ENOMEM;
 150
 151         size = params->hdr.e_phnum * sizeof(struct elf_phdr);
 152         params->phdrs = kmalloc(size, GFP_KERNEL);
 153         if (!params->phdrs)
 154                 return -ENOMEM;
 155
 156         retval = kernel_read(file, params->phdrs, size, &pos);
 157         if (unlikely(retval != size))
 158                 return retval < 0 ? retval : -ENOEXEC;
 159
 160         /* determine stack size for this binary */
 161         phdr = params->phdrs;
 162         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 163                 if (phdr->p_type != PT_GNU_STACK)
 164                         continue;
 165
 166                 if (phdr->p_flags & PF_X)
 167                         params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
 168                 else
 169                         params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
 170
 171                 params->stack_size = phdr->p_memsz;
 172                 break;
 173         }
 174
 175         return 0;
 176 }
 177
 178 /*****************************************************************************/
 179 /*
 180  * load an fdpic binary into various bits of memory
 181  */
 182 static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 183 {
 184         struct elf_fdpic_params exec_params, interp_params;
 185         struct pt_regs *regs = current_pt_regs();
 186         struct elf_phdr *phdr;
 187         unsigned long stack_size, entryaddr;
 188 #ifdef ELF_FDPIC_PLAT_INIT
 189         unsigned long dynaddr;
 190 #endif
 191 #ifndef CONFIG_MMU
 192         unsigned long stack_prot;
 193 #endif
 194         struct file *interpreter = NULL; /* to shut gcc up */
 195         char *interpreter_name = NULL;
 196         int executable_stack;
 197         int retval, i;
 198         loff_t pos;
 199
 200         kdebug("____ LOAD %d ____", current->pid);
 201
 202         memset(&exec_params, 0, sizeof(exec_params));
 203         memset(&interp_params, 0, sizeof(interp_params));
 204
 205         exec_params.hdr = *(struct elfhdr *) bprm->buf;
 206         exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
 207
 208         /* check that this is a binary we know how to deal with */
 209         retval = -ENOEXEC;
 210         if (!is_elf(&exec_params.hdr, bprm->file))
 211                 goto error;
 212         if (!elf_check_fdpic(&exec_params.hdr)) {
 213 #ifdef CONFIG_MMU
 214                 /* binfmt_elf handles non-fdpic elf except on nommu */
 215                 goto error;
 216 #else
 217                 /* nommu can only load ET_DYN (PIE) ELF */
 218                 if (exec_params.hdr.e_type != ET_DYN)
 219                         goto error;
 220 #endif
 221         }
 222
 223         /* read the program header table */
 224         retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
 225         if (retval < 0)
 226                 goto error;
 227
 228         /* scan for a program header that specifies an interpreter */
 229         phdr = exec_params.phdrs;
 230
 231         for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
 232                 switch (phdr->p_type) {
 233                 case PT_INTERP:
 234                         retval = -ENOMEM;
 235                         if (phdr->p_filesz > PATH_MAX)
 236                                 goto error;
 237                         retval = -ENOENT;
 238                         if (phdr->p_filesz < 2)
 239                                 goto error;
 240
 241                         /* read the name of the interpreter into memory */
 242                         interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
 243                         if (!interpreter_name)
 244                                 goto error;
 245
 246                         pos = phdr->p_offset;
 247                         retval = kernel_read(bprm->file, interpreter_name,
 248                                              phdr->p_filesz, &pos);
 249                         if (unlikely(retval != phdr->p_filesz)) {
 250                                 if (retval >= 0)
 251                                         retval = -ENOEXEC;
 252                                 goto error;
 253                         }
 254
 255                         retval = -ENOENT;
 256                         if (interpreter_name[phdr->p_filesz - 1] != '\0')
 257                                 goto error;
 258
 259                         kdebug("Using ELF interpreter %s", interpreter_name);
 260
 261                         /* replace the program with the interpreter */
 262                         interpreter = open_exec(interpreter_name);
 263                         retval = PTR_ERR(interpreter);
 264                         if (IS_ERR(interpreter)) {
 265                                 interpreter = NULL;
 266                                 goto error;
 267                         }
 268
 269                         /*
 270                          * If the binary is not readable then enforce
 271                          * mm->dumpable = 0 regardless of the interpreter's
 272                          * permissions.
 273                          */
 274                         would_dump(bprm, interpreter);
 275
 276                         pos = 0;
 277                         retval = kernel_read(interpreter, bprm->buf,
 278                                         BINPRM_BUF_SIZE, &pos);
 279                         if (unlikely(retval != BINPRM_BUF_SIZE)) {
 280                                 if (retval >= 0)
 281                                         retval = -ENOEXEC;
 282                                 goto error;
 283                         }
 284
 285                         interp_params.hdr = *((struct elfhdr *) bprm->buf);
 286                         break;
 287
 288                 case PT_LOAD:
 289 #ifdef CONFIG_MMU
 290                         if (exec_params.load_addr == 0)
 291                                 exec_params.load_addr = phdr->p_vaddr;
 292 #endif
 293                         break;
 294                 }
 295
 296         }
 297
 298         if (is_constdisp(&exec_params.hdr))
 299                 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 300
 301         /* perform insanity checks on the interpreter */
 302         if (interpreter_name) {
 303                 retval = -ELIBBAD;
 304                 if (!is_elf(&interp_params.hdr, interpreter))
 305                         goto error;
 306
 307                 interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
 308
 309                 /* read the interpreter's program header table */
 310                 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
 311                 if (retval < 0)
 312                         goto error;
 313         }
 314
 315         stack_size = exec_params.stack_size;
 316         if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 317                 executable_stack = EXSTACK_ENABLE_X;
 318         else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 319                 executable_stack = EXSTACK_DISABLE_X;
 320         else
 321                 executable_stack = EXSTACK_DEFAULT;
 322
 323         if (stack_size == 0) {
 324                 stack_size = interp_params.stack_size;
 325                 if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
 326                         executable_stack = EXSTACK_ENABLE_X;
 327                 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
 328                         executable_stack = EXSTACK_DISABLE_X;
 329                 else
 330                         executable_stack = EXSTACK_DEFAULT;
 331         }
 332
 333         retval = -ENOEXEC;
 334         if (stack_size == 0)
 335                 stack_size = 131072UL; /* same as exec.c's default commit */
 336
 337         if (is_constdisp(&interp_params.hdr))
 338                 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
 339
 340         /* flush all traces of the currently running executable */
 341         retval = begin_new_exec(bprm);
 342         if (retval)
 343                 goto error;
 344
 345         /* there's now no turning back... the old userspace image is dead,
 346          * defunct, deceased, etc.
 347          */
 348         if (elf_check_fdpic(&exec_params.hdr))
 349                 set_personality(PER_LINUX_FDPIC);
 350         else
 351                 set_personality(PER_LINUX);
 352         if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
 353                 current->personality |= READ_IMPLIES_EXEC;
 354
 355         setup_new_exec(bprm);
 356
 357         set_binfmt(&elf_fdpic_format);
 358
 359         current->mm->start_code = 0;
 360         current->mm->end_code = 0;
 361         current->mm->start_stack = 0;
 362         current->mm->start_data = 0;
 363         current->mm->end_data = 0;
 364         current->mm->context.exec_fdpic_loadmap = 0;
 365         current->mm->context.interp_fdpic_loadmap = 0;
 366
 367 #ifdef CONFIG_MMU
 368         elf_fdpic_arch_lay_out_mm(&exec_params,
 369                                   &interp_params,
 370                                   &current->mm->start_stack,
 371                                   &current->mm->start_brk);
 372
 373         retval = setup_arg_pages(bprm, current->mm->start_stack,
 374                                  executable_stack);
 375         if (retval < 0)
 376                 goto error;
 377 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 378         retval = arch_setup_additional_pages(bprm, !!interpreter_name);
 379         if (retval < 0)
 380                 goto error;
 381 #endif
 382 #endif
 383
 384         /* load the executable and interpreter into memory */
 385         retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
 386                                     "executable");
 387         if (retval < 0)
 388                 goto error;
 389
 390         if (interpreter_name) {
 391                 retval = elf_fdpic_map_file(&interp_params, interpreter,
 392                                             current->mm, "interpreter");
 393                 if (retval < 0) {
 394                         printk(KERN_ERR "Unable to load interpreter\n");
 395                         goto error;
 396                 }
 397
 398                 allow_write_access(interpreter);
 399                 fput(interpreter);
 400                 interpreter = NULL;
 401         }
 402
 403 #ifdef CONFIG_MMU
 404         if (!current->mm->start_brk)
 405                 current->mm->start_brk = current->mm->end_data;
 406
 407         current->mm->brk = current->mm->start_brk =
 408                 PAGE_ALIGN(current->mm->start_brk);
 409
 410 #else
 411         /* create a stack area and zero-size brk area */
 412         stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
 413         if (stack_size < PAGE_SIZE * 2)
 414                 stack_size = PAGE_SIZE * 2;
 415
 416         stack_prot = PROT_READ | PROT_WRITE;
 417         if (executable_stack == EXSTACK_ENABLE_X ||
 418             (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
 419                 stack_prot |= PROT_EXEC;
 420
 421         current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
 422                                          MAP_PRIVATE | MAP_ANONYMOUS |
 423                                          MAP_UNINITIALIZED | MAP_GROWSDOWN,
 424                                          0);
 425
 426         if (IS_ERR_VALUE(current->mm->start_brk)) {
 427                 retval = current->mm->start_brk;
 428                 current->mm->start_brk = 0;
 429                 goto error;
 430         }
 431
 432         current->mm->brk = current->mm->start_brk;
 433         current->mm->context.end_brk = current->mm->start_brk;
 434         current->mm->start_stack = current->mm->start_brk + stack_size;
 435 #endif
 436
 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         finalize_exec(bprm);
 462         /* everything is now ready... get the userspace context ready to roll */
 463         entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
 464         start_thread(regs, entryaddr, current->mm->start_stack);
 465
 466         retval = 0;
 467
 468 error:
 469         if (interpreter) {
 470                 allow_write_access(interpreter);
 471                 fput(interpreter);
 472         }
 473         kfree(interpreter_name);
 474         kfree(exec_params.phdrs);
 475         kfree(exec_params.loadmap);
 476         kfree(interp_params.phdrs);
 477         kfree(interp_params.loadmap);
 478         return retval;
 479 }
 480
 481 /*****************************************************************************/
 482
 483 #ifndef ELF_BASE_PLATFORM
 484 /*
 485  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 486  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 487  * will be copied to the user stack in the same manner as AT_PLATFORM.
 488  */
 489 #define ELF_BASE_PLATFORM NULL
 490 #endif
 491
 492 /*
 493  * present useful information to the program by shovelling it onto the new
 494  * process's stack
 495  */
 496 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 497                                    struct mm_struct *mm,
 498                                    struct elf_fdpic_params *exec_params,
 499                                    struct elf_fdpic_params *interp_params)
 500 {
 501         const struct cred *cred = current_cred();
 502         unsigned long sp, csp, nitems;
 503         elf_caddr_t __user *argv, *envp;
 504         size_t platform_len = 0, len;
 505         char *k_platform, *k_base_platform;
 506         char __user *u_platform, *u_base_platform, *p;
 507         int loop;
 508         int nr; /* reset for each csp adjustment */
 509
 510 #ifdef CONFIG_MMU
 511         /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 512          * by the processes running on the same package. One thing we can do is
 513          * to shuffle the initial stack for them, so we give the architecture
 514          * an opportunity to do so here.
 515          */
 516         sp = arch_align_stack(bprm->p);
 517 #else
 518         sp = mm->start_stack;
 519
 520         /* stack the program arguments and environment */
 521         if (transfer_args_to_stack(bprm, &sp) < 0)
 522                 return -EFAULT;
 523         sp &= ~15;
 524 #endif
 525
 526         /*
 527          * If this architecture has a platform capability string, copy it
 528          * to userspace.  In some cases (Sparc), this info is impossible
 529          * for userspace to get any other way, in others (i386) it is
 530          * merely difficult.
 531          */
 532         k_platform = ELF_PLATFORM;
 533         u_platform = NULL;
 534
 535         if (k_platform) {
 536                 platform_len = strlen(k_platform) + 1;
 537                 sp -= platform_len;
 538                 u_platform = (char __user *) sp;
 539                 if (copy_to_user(u_platform, k_platform, platform_len) != 0)
 540                         return -EFAULT;
 541         }
 542
 543         /*
 544          * If this architecture has a "base" platform capability
 545          * string, copy it to userspace.
 546          */
 547         k_base_platform = ELF_BASE_PLATFORM;
 548         u_base_platform = NULL;
 549
 550         if (k_base_platform) {
 551                 platform_len = strlen(k_base_platform) + 1;
 552                 sp -= platform_len;
 553                 u_base_platform = (char __user *) sp;
 554                 if (copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
 555                         return -EFAULT;
 556         }
 557
 558         sp &= ~7UL;
 559
 560         /* stack the load map(s) */
 561         len = sizeof(struct elf32_fdpic_loadmap);
 562         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 563         sp = (sp - len) & ~7UL;
 564         exec_params->map_addr = sp;
 565
 566         if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
 567                 return -EFAULT;
 568
 569         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 570
 571         if (interp_params->loadmap) {
 572                 len = sizeof(struct elf32_fdpic_loadmap);
 573                 len += sizeof(struct elf32_fdpic_loadseg) *
 574                         interp_params->loadmap->nsegs;
 575                 sp = (sp - len) & ~7UL;
 576                 interp_params->map_addr = sp;
 577
 578                 if (copy_to_user((void __user *) sp, interp_params->loadmap,
 579                                  len) != 0)
 580                         return -EFAULT;
 581
 582                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 583         }
 584
 585         /* force 16 byte _final_ alignment here for generality */
 586 #define DLINFO_ITEMS 15
 587
 588         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
 589                 (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
 590
 591         if (bprm->have_execfd)
 592                 nitems++;
 593
 594         csp = sp;
 595         sp -= nitems * 2 * sizeof(unsigned long);
 596         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 597         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 598         sp -= 1 * sizeof(unsigned long);                /* argc */
 599
 600         csp -= sp & 15UL;
 601         sp -= sp & 15UL;
 602
 603         /* put the ELF interpreter info on the stack */
 604 #define NEW_AUX_ENT(id, val)                                            \
 605         do {                                                            \
 606                 struct { unsigned long _id, _val; } __user *ent, v;     \
 607                                                                         \
 608                 ent = (void __user *) csp;                              \
 609                 v._id = (id);                                           \
 610                 v._val = (val);                                         \
 611                 if (copy_to_user(ent + nr, &v, sizeof(v)))              \
 612                         return -EFAULT;                                 \
 613                 nr++;                                                   \
 614         } while (0)
 615
 616         nr = 0;
 617         csp -= 2 * sizeof(unsigned long);
 618         NEW_AUX_ENT(AT_NULL, 0);
 619         if (k_platform) {
 620                 nr = 0;
 621                 csp -= 2 * sizeof(unsigned long);
 622                 NEW_AUX_ENT(AT_PLATFORM,
 623                             (elf_addr_t) (unsigned long) u_platform);
 624         }
 625
 626         if (k_base_platform) {
 627                 nr = 0;
 628                 csp -= 2 * sizeof(unsigned long);
 629                 NEW_AUX_ENT(AT_BASE_PLATFORM,
 630                             (elf_addr_t) (unsigned long) u_base_platform);
 631         }
 632
 633         if (bprm->have_execfd) {
 634                 nr = 0;
 635                 csp -= 2 * sizeof(unsigned long);
 636                 NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
 637         }
 638
 639         nr = 0;
 640         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 641         NEW_AUX_ENT(AT_HWCAP,   ELF_HWCAP);
 642 #ifdef ELF_HWCAP2
 643         NEW_AUX_ENT(AT_HWCAP2,  ELF_HWCAP2);
 644 #endif
 645         NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
 646         NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
 647         NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
 648         NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
 649         NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
 650         NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
 651         NEW_AUX_ENT(AT_FLAGS,   0);
 652         NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
 653         NEW_AUX_ENT(AT_UID,     (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
 654         NEW_AUX_ENT(AT_EUID,    (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
 655         NEW_AUX_ENT(AT_GID,     (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
 656         NEW_AUX_ENT(AT_EGID,    (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
 657         NEW_AUX_ENT(AT_SECURE,  bprm->secureexec);
 658         NEW_AUX_ENT(AT_EXECFN,  bprm->exec);
 659
 660 #ifdef ARCH_DLINFO
 661         nr = 0;
 662         csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
 663
 664         /* ARCH_DLINFO must come last so platform specific code can enforce
 665          * special alignment requirements on the AUXV if necessary (eg. PPC).
 666          */
 667         ARCH_DLINFO;
 668 #endif
 669 #undef NEW_AUX_ENT
 670
 671         /* allocate room for argv[] and envv[] */
 672         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 673         envp = (elf_caddr_t __user *) csp;
 674         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 675         argv = (elf_caddr_t __user *) csp;
 676
 677         /* stack argc */
 678         csp -= sizeof(unsigned long);
 679         if (put_user(bprm->argc, (unsigned long __user *) csp))
 680                 return -EFAULT;
 681
 682         BUG_ON(csp != sp);
 683
 684         /* fill in the argv[] array */
 685 #ifdef CONFIG_MMU
 686         current->mm->arg_start = bprm->p;
 687 #else
 688         current->mm->arg_start = current->mm->start_stack -
 689                 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 690 #endif
 691
 692         p = (char __user *) current->mm->arg_start;
 693         for (loop = bprm->argc; loop > 0; loop--) {
 694                 if (put_user((elf_caddr_t) p, argv++))
 695                         return -EFAULT;
 696                 len = strnlen_user(p, MAX_ARG_STRLEN);
 697                 if (!len || len > MAX_ARG_STRLEN)
 698                         return -EINVAL;
 699                 p += len;
 700         }
 701         if (put_user(NULL, argv))
 702                 return -EFAULT;
 703         current->mm->arg_end = (unsigned long) p;
 704
 705         /* fill in the envv[] array */
 706         current->mm->env_start = (unsigned long) p;
 707         for (loop = bprm->envc; loop > 0; loop--) {
 708                 if (put_user((elf_caddr_t)(unsigned long) p, envp++))
 709                         return -EFAULT;
 710                 len = strnlen_user(p, MAX_ARG_STRLEN);
 711                 if (!len || len > MAX_ARG_STRLEN)
 712                         return -EINVAL;
 713                 p += len;
 714         }
 715         if (put_user(NULL, envp))
 716                 return -EFAULT;
 717         current->mm->env_end = (unsigned long) p;
 718
 719         mm->start_stack = (unsigned long) sp;
 720         return 0;
 721 }
 722
 723 /*****************************************************************************/
 724 /*
 725  * load the appropriate binary image (executable or interpreter) into memory
 726  * - we assume no MMU is available
 727  * - if no other PIC bits are set in params->hdr->e_flags
 728  *   - we assume that the LOADable segments in the binary are independently relocatable
 729  *   - we assume R/O executable segments are shareable
 730  * - else
 731  *   - we assume the loadable parts of the image to require fixed displacement
 732  *   - the image is not shareable
 733  */
 734 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 735                               struct file *file,
 736                               struct mm_struct *mm,
 737                               const char *what)
 738 {
 739         struct elf32_fdpic_loadmap *loadmap;
 740 #ifdef CONFIG_MMU
 741         struct elf32_fdpic_loadseg *mseg;
 742 #endif
 743         struct elf32_fdpic_loadseg *seg;
 744         struct elf32_phdr *phdr;
 745         unsigned long load_addr, stop;
 746         unsigned nloads, tmp;
 747         size_t size;
 748         int loop, ret;
 749
 750         /* allocate a load map table */
 751         nloads = 0;
 752         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 753                 if (params->phdrs[loop].p_type == PT_LOAD)
 754                         nloads++;
 755
 756         if (nloads == 0)
 757                 return -ELIBBAD;
 758
 759         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 760         loadmap = kzalloc(size, GFP_KERNEL);
 761         if (!loadmap)
 762                 return -ENOMEM;
 763
 764         params->loadmap = loadmap;
 765
 766         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 767         loadmap->nsegs = nloads;
 768
 769         load_addr = params->load_addr;
 770         seg = loadmap->segs;
 771
 772         /* map the requested LOADs into the memory space */
 773         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 774         case ELF_FDPIC_FLAG_CONSTDISP:
 775         case ELF_FDPIC_FLAG_CONTIGUOUS:
 776 #ifndef CONFIG_MMU
 777                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 778                 if (ret < 0)
 779                         return ret;
 780                 break;
 781 #endif
 782         default:
 783                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 784                 if (ret < 0)
 785                         return ret;
 786                 break;
 787         }
 788
 789         /* map the entry point */
 790         if (params->hdr.e_entry) {
 791                 seg = loadmap->segs;
 792                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 793                         if (params->hdr.e_entry >= seg->p_vaddr &&
 794                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
 795                                 params->entry_addr =
 796                                         (params->hdr.e_entry - seg->p_vaddr) +
 797                                         seg->addr;
 798                                 break;
 799                         }
 800                 }
 801         }
 802
 803         /* determine where the program header table has wound up if mapped */
 804         stop = params->hdr.e_phoff;
 805         stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
 806         phdr = params->phdrs;
 807
 808         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 809                 if (phdr->p_type != PT_LOAD)
 810                         continue;
 811
 812                 if (phdr->p_offset > params->hdr.e_phoff ||
 813                     phdr->p_offset + phdr->p_filesz < stop)
 814                         continue;
 815
 816                 seg = loadmap->segs;
 817                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 818                         if (phdr->p_vaddr >= seg->p_vaddr &&
 819                             phdr->p_vaddr + phdr->p_filesz <=
 820                             seg->p_vaddr + seg->p_memsz) {
 821                                 params->ph_addr =
 822                                         (phdr->p_vaddr - seg->p_vaddr) +
 823                                         seg->addr +
 824                                         params->hdr.e_phoff - phdr->p_offset;
 825                                 break;
 826                         }
 827                 }
 828                 break;
 829         }
 830
 831         /* determine where the dynamic section has wound up if there is one */
 832         phdr = params->phdrs;
 833         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 834                 if (phdr->p_type != PT_DYNAMIC)
 835                         continue;
 836
 837                 seg = loadmap->segs;
 838                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 839                         if (phdr->p_vaddr >= seg->p_vaddr &&
 840                             phdr->p_vaddr + phdr->p_memsz <=
 841                             seg->p_vaddr + seg->p_memsz) {
 842                                 Elf32_Dyn __user *dyn;
 843                                 Elf32_Sword d_tag;
 844
 845                                 params->dynamic_addr =
 846                                         (phdr->p_vaddr - seg->p_vaddr) +
 847                                         seg->addr;
 848
 849                                 /* check the dynamic section contains at least
 850                                  * one item, and that the last item is a NULL
 851                                  * entry */
 852                                 if (phdr->p_memsz == 0 ||
 853                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 854                                         goto dynamic_error;
 855
 856                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 857                                 dyn = (Elf32_Dyn __user *)params->dynamic_addr;
 858                                 if (get_user(d_tag, &dyn[tmp - 1].d_tag) ||
 859                                     d_tag != 0)
 860                                         goto dynamic_error;
 861                                 break;
 862                         }
 863                 }
 864                 break;
 865         }
 866
 867         /* now elide adjacent segments in the load map on MMU linux
 868          * - on uClinux the holes between may actually be filled with system
 869          *   stuff or stuff from other processes
 870          */
 871 #ifdef CONFIG_MMU
 872         nloads = loadmap->nsegs;
 873         mseg = loadmap->segs;
 874         seg = mseg + 1;
 875         for (loop = 1; loop < nloads; loop++) {
 876                 /* see if we have a candidate for merging */
 877                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 878                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 879                         if (load_addr == (seg->addr & PAGE_MASK)) {
 880                                 mseg->p_memsz +=
 881                                         load_addr -
 882                                         (mseg->addr + mseg->p_memsz);
 883                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 884                                 mseg->p_memsz += seg->p_memsz;
 885                                 loadmap->nsegs--;
 886                                 continue;
 887                         }
 888                 }
 889
 890                 mseg++;
 891                 if (mseg != seg)
 892                         *mseg = *seg;
 893         }
 894 #endif
 895
 896         kdebug("Mapped Object [%s]:", what);
 897         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 898         kdebug("- entry    : %lx", params->entry_addr);
 899         kdebug("- PHDR[]   : %lx", params->ph_addr);
 900         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 901         seg = loadmap->segs;
 902         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 903                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 904                        loop,
 905                        seg->addr, seg->addr + seg->p_memsz - 1,
 906                        seg->p_vaddr, seg->p_memsz);
 907
 908         return 0;
 909
 910 dynamic_error:
 911         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 912                what, file_inode(file)->i_ino);
 913         return -ELIBBAD;
 914 }
 915
 916 /*****************************************************************************/
 917 /*
 918  * map a file with constant displacement under uClinux
 919  */
 920 #ifndef CONFIG_MMU
 921 static int elf_fdpic_map_file_constdisp_on_uclinux(
 922         struct elf_fdpic_params *params,
 923         struct file *file,
 924         struct mm_struct *mm)
 925 {
 926         struct elf32_fdpic_loadseg *seg;
 927         struct elf32_phdr *phdr;
 928         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 929         int loop, ret;
 930
 931         load_addr = params->load_addr;
 932         seg = params->loadmap->segs;
 933
 934         /* determine the bounds of the contiguous overall allocation we must
 935          * make */
 936         phdr = params->phdrs;
 937         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 938                 if (params->phdrs[loop].p_type != PT_LOAD)
 939                         continue;
 940
 941                 if (base > phdr->p_vaddr)
 942                         base = phdr->p_vaddr;
 943                 if (top < phdr->p_vaddr + phdr->p_memsz)
 944                         top = phdr->p_vaddr + phdr->p_memsz;
 945         }
 946
 947         /* allocate one big anon block for everything */
 948         mflags = MAP_PRIVATE;
 949         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 950                 mflags |= MAP_EXECUTABLE;
 951
 952         maddr = vm_mmap(NULL, load_addr, top - base,
 953                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 954         if (IS_ERR_VALUE(maddr))
 955                 return (int) maddr;
 956
 957         if (load_addr != 0)
 958                 load_addr += PAGE_ALIGN(top - base);
 959
 960         /* and then load the file segments into it */
 961         phdr = params->phdrs;
 962         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 963                 if (params->phdrs[loop].p_type != PT_LOAD)
 964                         continue;
 965
 966                 seg->addr = maddr + (phdr->p_vaddr - base);
 967                 seg->p_vaddr = phdr->p_vaddr;
 968                 seg->p_memsz = phdr->p_memsz;
 969
 970                 ret = read_code(file, seg->addr, phdr->p_offset,
 971                                        phdr->p_filesz);
 972                 if (ret < 0)
 973                         return ret;
 974
 975                 /* map the ELF header address if in this segment */
 976                 if (phdr->p_offset == 0)
 977                         params->elfhdr_addr = seg->addr;
 978
 979                 /* clear any space allocated but not loaded */
 980                 if (phdr->p_filesz < phdr->p_memsz) {
 981                         if (clear_user((void *) (seg->addr + phdr->p_filesz),
 982                                        phdr->p_memsz - phdr->p_filesz))
 983                                 return -EFAULT;
 984                 }
 985
 986                 if (mm) {
 987                         if (phdr->p_flags & PF_X) {
 988                                 if (!mm->start_code) {
 989                                         mm->start_code = seg->addr;
 990                                         mm->end_code = seg->addr +
 991                                                 phdr->p_memsz;
 992                                 }
 993                         } else if (!mm->start_data) {
 994                                 mm->start_data = seg->addr;
 995                                 mm->end_data = seg->addr + phdr->p_memsz;
 996                         }
 997                 }
 998
 999                 seg++;
1000         }
1001
1002         return 0;
1003 }
1004 #endif
1005
1006 /*****************************************************************************/
1007 /*
1008  * map a binary by direct mmap() of the individual PT_LOAD segments
1009  */
1010 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
1011                                              struct file *file,
1012                                              struct mm_struct *mm)
1013 {
1014         struct elf32_fdpic_loadseg *seg;
1015         struct elf32_phdr *phdr;
1016         unsigned long load_addr, delta_vaddr;
1017         int loop, dvset;
1018
1019         load_addr = params->load_addr;
1020         delta_vaddr = 0;
1021         dvset = 0;
1022
1023         seg = params->loadmap->segs;
1024
1025         /* deal with each load segment separately */
1026         phdr = params->phdrs;
1027         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1028                 unsigned long maddr, disp, excess, excess1;
1029                 int prot = 0, flags;
1030
1031                 if (phdr->p_type != PT_LOAD)
1032                         continue;
1033
1034                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1035                        (unsigned long) phdr->p_vaddr,
1036                        (unsigned long) phdr->p_offset,
1037                        (unsigned long) phdr->p_filesz,
1038                        (unsigned long) phdr->p_memsz);
1039
1040                 /* determine the mapping parameters */
1041                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
1042                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1043                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1044
1045                 flags = MAP_PRIVATE | MAP_DENYWRITE;
1046                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
1047                         flags |= MAP_EXECUTABLE;
1048
1049                 maddr = 0;
1050
1051                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1052                 case ELF_FDPIC_FLAG_INDEPENDENT:
1053                         /* PT_LOADs are independently locatable */
1054                         break;
1055
1056                 case ELF_FDPIC_FLAG_HONOURVADDR:
1057                         /* the specified virtual address must be honoured */
1058                         maddr = phdr->p_vaddr;
1059                         flags |= MAP_FIXED;
1060                         break;
1061
1062                 case ELF_FDPIC_FLAG_CONSTDISP:
1063                         /* constant displacement
1064                          * - can be mapped anywhere, but must be mapped as a
1065                          *   unit
1066                          */
1067                         if (!dvset) {
1068                                 maddr = load_addr;
1069                                 delta_vaddr = phdr->p_vaddr;
1070                                 dvset = 1;
1071                         } else {
1072                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1073                                 flags |= MAP_FIXED;
1074                         }
1075                         break;
1076
1077                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1078                         /* contiguity handled later */
1079                         break;
1080
1081                 default:
1082                         BUG();
1083                 }
1084
1085                 maddr &= PAGE_MASK;
1086
1087                 /* create the mapping */
1088                 disp = phdr->p_vaddr & ~PAGE_MASK;
1089                 maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1090                                 phdr->p_offset - disp);
1091
1092                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1093                        loop, phdr->p_memsz + disp, prot, flags,
1094                        phdr->p_offset - disp, maddr);
1095
1096                 if (IS_ERR_VALUE(maddr))
1097                         return (int) maddr;
1098
1099                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1100                     ELF_FDPIC_FLAG_CONTIGUOUS)
1101                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1102
1103                 seg->addr = maddr + disp;
1104                 seg->p_vaddr = phdr->p_vaddr;
1105                 seg->p_memsz = phdr->p_memsz;
1106
1107                 /* map the ELF header address if in this segment */
1108                 if (phdr->p_offset == 0)
1109                         params->elfhdr_addr = seg->addr;
1110
1111                 /* clear the bit between beginning of mapping and beginning of
1112                  * PT_LOAD */
1113                 if (prot & PROT_WRITE && disp > 0) {
1114                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1115                         if (clear_user((void __user *) maddr, disp))
1116                                 return -EFAULT;
1117                         maddr += disp;
1118                 }
1119
1120                 /* clear any space allocated but not loaded
1121                  * - on uClinux we can just clear the lot
1122                  * - on MMU linux we'll get a SIGBUS beyond the last page
1123                  *   extant in the file
1124                  */
1125                 excess = phdr->p_memsz - phdr->p_filesz;
1126                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1127
1128 #ifdef CONFIG_MMU
1129                 if (excess > excess1) {
1130                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1131                         unsigned long xmaddr;
1132
1133                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1134                         xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
1135                                          prot, flags, 0);
1136
1137                         kdebug("mmap[%d] <anon>"
1138                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1139                                loop, xaddr, excess - excess1, prot, flags,
1140                                xmaddr);
1141
1142                         if (xmaddr != xaddr)
1143                                 return -ENOMEM;
1144                 }
1145
1146                 if (prot & PROT_WRITE && excess1 > 0) {
1147                         kdebug("clear[%d] ad=%lx sz=%lx",
1148                                loop, maddr + phdr->p_filesz, excess1);
1149                         if (clear_user((void __user *) maddr + phdr->p_filesz,
1150                                        excess1))
1151                                 return -EFAULT;
1152                 }
1153
1154 #else
1155                 if (excess > 0) {
1156                         kdebug("clear[%d] ad=%lx sz=%lx",
1157                                loop, maddr + phdr->p_filesz, excess);
1158                         if (clear_user((void *) maddr + phdr->p_filesz, excess))
1159                                 return -EFAULT;
1160                 }
1161 #endif
1162
1163                 if (mm) {
1164                         if (phdr->p_flags & PF_X) {
1165                                 if (!mm->start_code) {
1166                                         mm->start_code = maddr;
1167                                         mm->end_code = maddr + phdr->p_memsz;
1168                                 }
1169                         } else if (!mm->start_data) {
1170                                 mm->start_data = maddr;
1171                                 mm->end_data = maddr + phdr->p_memsz;
1172                         }
1173                 }
1174
1175                 seg++;
1176         }
1177
1178         return 0;
1179 }
1180
1181 /*****************************************************************************/
1182 /*
1183  * ELF-FDPIC core dumper
1184  *
1185  * Modelled on fs/exec.c:aout_core_dump()
1186  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1187  *
1188  * Modelled on fs/binfmt_elf.c core dumper
1189  */
1190 #ifdef CONFIG_ELF_CORE
1191
1192 /*
1193  * Decide whether a segment is worth dumping; default is yes to be
1194  * sure (missing info is worse than too much; etc).
1195  * Personally I'd include everything, and use the coredump limit...
1196  *
1197  * I think we should skip something. But I am not sure how. H.J.
1198  */
1199 static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
1200 {
1201         int dump_ok;
1202
1203         /* Do not dump I/O mapped devices or special mappings */
1204         if (vma->vm_flags & VM_IO) {
1205                 kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
1206                 return 0;
1207         }
1208
1209         /* If we may not read the contents, don't allow us to dump
1210          * them either. "dump_write()" can't handle it anyway.
1211          */
1212         if (!(vma->vm_flags & VM_READ)) {
1213                 kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
1214                 return 0;
1215         }
1216
1217         /* support for DAX */
1218         if (vma_is_dax(vma)) {
1219                 if (vma->vm_flags & VM_SHARED) {
1220                         dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
1221                         kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
1222                                vma->vm_flags, dump_ok ? "yes" : "no");
1223                 } else {
1224                         dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
1225                         kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
1226                                vma->vm_flags, dump_ok ? "yes" : "no");
1227                 }
1228                 return dump_ok;
1229         }
1230
1231         /* By default, dump shared memory if mapped from an anonymous file. */
1232         if (vma->vm_flags & VM_SHARED) {
1233                 if (file_inode(vma->vm_file)->i_nlink == 0) {
1234                         dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
1235                         kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1236                                vma->vm_flags, dump_ok ? "yes" : "no");
1237                         return dump_ok;
1238                 }
1239
1240                 dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
1241                 kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
1242                        vma->vm_flags, dump_ok ? "yes" : "no");
1243                 return dump_ok;
1244         }
1245
1246 #ifdef CONFIG_MMU
1247         /* By default, if it hasn't been written to, don't write it out */
1248         if (!vma->anon_vma) {
1249                 dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
1250                 kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
1251                        vma->vm_flags, dump_ok ? "yes" : "no");
1252                 return dump_ok;
1253         }
1254 #endif
1255
1256         dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
1257         kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
1258                dump_ok ? "yes" : "no");
1259         return dump_ok;
1260 }
1261
1262 /* An ELF note in memory */
1263 struct memelfnote
1264 {
1265         const char *name;
1266         int type;
1267         unsigned int datasz;
1268         void *data;
1269 };
1270
1271 static int notesize(struct memelfnote *en)
1272 {
1273         int sz;
1274
1275         sz = sizeof(struct elf_note);
1276         sz += roundup(strlen(en->name) + 1, 4);
1277         sz += roundup(en->datasz, 4);
1278
1279         return sz;
1280 }
1281
1282 /* #define DEBUG */
1283
1284 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1285 {
1286         struct elf_note en;
1287         en.n_namesz = strlen(men->name) + 1;
1288         en.n_descsz = men->datasz;
1289         en.n_type = men->type;
1290
1291         return dump_emit(cprm, &en, sizeof(en)) &&
1292                 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1293                 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1294 }
1295
1296 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1297 {
1298         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1299         elf->e_ident[EI_CLASS] = ELF_CLASS;
1300         elf->e_ident[EI_DATA] = ELF_DATA;
1301         elf->e_ident[EI_VERSION] = EV_CURRENT;
1302         elf->e_ident[EI_OSABI] = ELF_OSABI;
1303         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1304
1305         elf->e_type = ET_CORE;
1306         elf->e_machine = ELF_ARCH;
1307         elf->e_version = EV_CURRENT;
1308         elf->e_entry = 0;
1309         elf->e_phoff = sizeof(struct elfhdr);
1310         elf->e_shoff = 0;
1311         elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1312         elf->e_ehsize = sizeof(struct elfhdr);
1313         elf->e_phentsize = sizeof(struct elf_phdr);
1314         elf->e_phnum = segs;
1315         elf->e_shentsize = 0;
1316         elf->e_shnum = 0;
1317         elf->e_shstrndx = 0;
1318         return;
1319 }
1320
1321 static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1322 {
1323         phdr->p_type = PT_NOTE;
1324         phdr->p_offset = offset;
1325         phdr->p_vaddr = 0;
1326         phdr->p_paddr = 0;
1327         phdr->p_filesz = sz;
1328         phdr->p_memsz = 0;
1329         phdr->p_flags = 0;
1330         phdr->p_align = 0;
1331         return;
1332 }
1333
1334 static inline void fill_note(struct memelfnote *note, const char *name, int type,
1335                 unsigned int sz, void *data)
1336 {
1337         note->name = name;
1338         note->type = type;
1339         note->datasz = sz;
1340         note->data = data;
1341         return;
1342 }
1343
1344 /*
1345  * fill up all the fields in prstatus from the given task struct, except
1346  * registers which need to be filled up separately.
1347  */
1348 static void fill_prstatus(struct elf_prstatus *prstatus,
1349                           struct task_struct *p, long signr)
1350 {
1351         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1352         prstatus->pr_sigpend = p->pending.signal.sig[0];
1353         prstatus->pr_sighold = p->blocked.sig[0];
1354         rcu_read_lock();
1355         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1356         rcu_read_unlock();
1357         prstatus->pr_pid = task_pid_vnr(p);
1358         prstatus->pr_pgrp = task_pgrp_vnr(p);
1359         prstatus->pr_sid = task_session_vnr(p);
1360         if (thread_group_leader(p)) {
1361                 struct task_cputime cputime;
1362
1363                 /*
1364                  * This is the record for the group leader.  It shows the
1365                  * group-wide total, not its individual thread total.
1366                  */
1367                 thread_group_cputime(p, &cputime);
1368                 prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
1369                 prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1370         } else {
1371                 u64 utime, stime;
1372
1373                 task_cputime(p, &utime, &stime);
1374                 prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
1375                 prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1376         }
1377         prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
1378         prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1379
1380         prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1381         prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1382 }
1383
1384 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1385                        struct mm_struct *mm)
1386 {
1387         const struct cred *cred;
1388         unsigned int i, len;
1389
1390         /* first copy the parameters from user space */
1391         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1392
1393         len = mm->arg_end - mm->arg_start;
1394         if (len >= ELF_PRARGSZ)
1395                 len = ELF_PRARGSZ - 1;
1396         if (copy_from_user(&psinfo->pr_psargs,
1397                            (const char __user *) mm->arg_start, len))
1398                 return -EFAULT;
1399         for (i = 0; i < len; i++)
1400                 if (psinfo->pr_psargs[i] == 0)
1401                         psinfo->pr_psargs[i] = ' ';
1402         psinfo->pr_psargs[len] = 0;
1403
1404         rcu_read_lock();
1405         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1406         rcu_read_unlock();
1407         psinfo->pr_pid = task_pid_vnr(p);
1408         psinfo->pr_pgrp = task_pgrp_vnr(p);
1409         psinfo->pr_sid = task_session_vnr(p);
1410
1411         i = p->state ? ffz(~p->state) + 1 : 0;
1412         psinfo->pr_state = i;
1413         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1414         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1415         psinfo->pr_nice = task_nice(p);
1416         psinfo->pr_flag = p->flags;
1417         rcu_read_lock();
1418         cred = __task_cred(p);
1419         SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1420         SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1421         rcu_read_unlock();
1422         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1423
1424         return 0;
1425 }
1426
1427 /* Here is the structure in which status of each thread is captured. */
1428 struct elf_thread_status
1429 {
1430         struct list_head list;
1431         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1432         elf_fpregset_t fpu;             /* NT_PRFPREG */
1433         struct task_struct *thread;
1434 #ifdef ELF_CORE_COPY_XFPREGS
1435         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1436 #endif
1437         struct memelfnote notes[3];
1438         int num_notes;
1439 };
1440
1441 /*
1442  * In order to add the specific thread information for the elf file format,
1443  * we need to keep a linked list of every thread's pr_status and then create
1444  * a single section for them in the final core file.
1445  */
1446 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1447 {
1448         struct task_struct *p = t->thread;
1449         int sz = 0;
1450
1451         t->num_notes = 0;
1452
1453         fill_prstatus(&t->prstatus, p, signr);
1454         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1455
1456         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1457                   &t->prstatus);
1458         t->num_notes++;
1459         sz += notesize(&t->notes[0]);
1460
1461         t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
1462         if (t->prstatus.pr_fpvalid) {
1463                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1464                           &t->fpu);
1465                 t->num_notes++;
1466                 sz += notesize(&t->notes[1]);
1467         }
1468
1469 #ifdef ELF_CORE_COPY_XFPREGS
1470         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1471                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1472                           sizeof(t->xfpu), &t->xfpu);
1473                 t->num_notes++;
1474                 sz += notesize(&t->notes[2]);
1475         }
1476 #endif
1477         return sz;
1478 }
1479
1480 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1481                              elf_addr_t e_shoff, int segs)
1482 {
1483         elf->e_shoff = e_shoff;
1484         elf->e_shentsize = sizeof(*shdr4extnum);
1485         elf->e_shnum = 1;
1486         elf->e_shstrndx = SHN_UNDEF;
1487
1488         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1489
1490         shdr4extnum->sh_type = SHT_NULL;
1491         shdr4extnum->sh_size = elf->e_shnum;
1492         shdr4extnum->sh_link = elf->e_shstrndx;
1493         shdr4extnum->sh_info = segs;
1494 }
1495
1496 /*
1497  * dump the segments for an MMU process
1498  */
1499 static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
1500 {
1501         struct vm_area_struct *vma;
1502
1503         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1504 #ifdef CONFIG_MMU
1505                 unsigned long addr;
1506 #endif
1507
1508                 if (!maydump(vma, cprm->mm_flags))
1509                         continue;
1510
1511 #ifdef CONFIG_MMU
1512                 for (addr = vma->vm_start; addr < vma->vm_end;
1513                                                         addr += PAGE_SIZE) {
1514                         bool res;
1515                         struct page *page = get_dump_page(addr);
1516                         if (page) {
1517                                 void *kaddr = kmap(page);
1518                                 res = dump_emit(cprm, kaddr, PAGE_SIZE);
1519                                 kunmap(page);
1520                                 put_page(page);
1521                         } else {
1522                                 res = dump_skip(cprm, PAGE_SIZE);
1523                         }
1524                         if (!res)
1525                                 return false;
1526                 }
1527 #else
1528                 if (!dump_emit(cprm, (void *) vma->vm_start,
1529                                 vma->vm_end - vma->vm_start))
1530                         return false;
1531 #endif
1532         }
1533         return true;
1534 }
1535
1536 static size_t elf_core_vma_data_size(unsigned long mm_flags)
1537 {
1538         struct vm_area_struct *vma;
1539         size_t size = 0;
1540
1541         for (vma = current->mm->mmap; vma; vma = vma->vm_next)
1542                 if (maydump(vma, mm_flags))
1543                         size += vma->vm_end - vma->vm_start;
1544         return size;
1545 }
1546
1547 /*
1548  * Actual dumper
1549  *
1550  * This is a two-pass process; first we find the offsets of the bits,
1551  * and then they are actually written out.  If we run out of core limit
1552  * we just truncate.
1553  */
1554 static int elf_fdpic_core_dump(struct coredump_params *cprm)
1555 {
1556 #define NUM_NOTES       6
1557         int has_dumped = 0;
1558         int segs;
1559         int i;
1560         struct vm_area_struct *vma;
1561         struct elfhdr *elf = NULL;
1562         loff_t offset = 0, dataoff;
1563         int numnote;
1564         struct memelfnote *notes = NULL;
1565         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
1566         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
1567         LIST_HEAD(thread_list);
1568         struct list_head *t;
1569         elf_fpregset_t *fpu = NULL;
1570 #ifdef ELF_CORE_COPY_XFPREGS
1571         elf_fpxregset_t *xfpu = NULL;
1572 #endif
1573         int thread_status_size = 0;
1574         elf_addr_t *auxv;
1575         struct elf_phdr *phdr4note = NULL;
1576         struct elf_shdr *shdr4extnum = NULL;
1577         Elf_Half e_phnum;
1578         elf_addr_t e_shoff;
1579         struct core_thread *ct;
1580         struct elf_thread_status *tmp;
1581
1582         /*
1583          * We no longer stop all VM operations.
1584          *
1585          * This is because those proceses that could possibly change map_count
1586          * or the mmap / vma pages are now blocked in do_exit on current
1587          * finishing this core dump.
1588          *
1589          * Only ptrace can touch these memory addresses, but it doesn't change
1590          * the map_count or the pages allocated. So no possibility of crashing
1591          * exists while dumping the mm->vm_next areas to the core file.
1592          */
1593
1594         /* alloc memory for large data structures: too large to be on stack */
1595         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1596         if (!elf)
1597                 goto end_coredump;
1598         prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
1599         if (!prstatus)
1600                 goto end_coredump;
1601         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1602         if (!psinfo)
1603                 goto end_coredump;
1604         notes = kmalloc_array(NUM_NOTES, sizeof(struct memelfnote),
1605                               GFP_KERNEL);
1606         if (!notes)
1607                 goto end_coredump;
1608         fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1609         if (!fpu)
1610                 goto end_coredump;
1611 #ifdef ELF_CORE_COPY_XFPREGS
1612         xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1613         if (!xfpu)
1614                 goto end_coredump;
1615 #endif
1616
1617         for (ct = current->mm->core_state->dumper.next;
1618                                         ct; ct = ct->next) {
1619                 tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
1620                 if (!tmp)
1621                         goto end_coredump;
1622
1623                 tmp->thread = ct->task;
1624                 list_add(&tmp->list, &thread_list);
1625         }
1626
1627         list_for_each(t, &thread_list) {
1628                 struct elf_thread_status *tmp;
1629                 int sz;
1630
1631                 tmp = list_entry(t, struct elf_thread_status, list);
1632                 sz = elf_dump_thread_status(cprm->siginfo->si_signo, tmp);
1633                 thread_status_size += sz;
1634         }
1635
1636         /* now collect the dump for the current */
1637         fill_prstatus(prstatus, current, cprm->siginfo->si_signo);
1638         elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
1639
1640         segs = current->mm->map_count;
1641         segs += elf_core_extra_phdrs();
1642
1643         /* for notes section */
1644         segs++;
1645
1646         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1647          * this, kernel supports extended numbering. Have a look at
1648          * include/linux/elf.h for further information. */
1649         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1650
1651         /* Set up header */
1652         fill_elf_fdpic_header(elf, e_phnum);
1653
1654         has_dumped = 1;
1655         /*
1656          * Set up the notes in similar form to SVR4 core dumps made
1657          * with info from their /proc.
1658          */
1659
1660         fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1661         fill_psinfo(psinfo, current->group_leader, current->mm);
1662         fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1663
1664         numnote = 2;
1665
1666         auxv = (elf_addr_t *) current->mm->saved_auxv;
1667
1668         i = 0;
1669         do
1670                 i += 2;
1671         while (auxv[i - 2] != AT_NULL);
1672         fill_note(&notes[numnote++], "CORE", NT_AUXV,
1673                   i * sizeof(elf_addr_t), auxv);
1674
1675         /* Try to dump the FPU. */
1676         if ((prstatus->pr_fpvalid =
1677              elf_core_copy_task_fpregs(current, cprm->regs, fpu)))
1678                 fill_note(notes + numnote++,
1679                           "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1680 #ifdef ELF_CORE_COPY_XFPREGS
1681         if (elf_core_copy_task_xfpregs(current, xfpu))
1682                 fill_note(notes + numnote++,
1683                           "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
1684 #endif
1685
1686         offset += sizeof(*elf);                         /* Elf header */
1687         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
1688
1689         /* Write notes phdr entry */
1690         {
1691                 int sz = 0;
1692
1693                 for (i = 0; i < numnote; i++)
1694                         sz += notesize(notes + i);
1695
1696                 sz += thread_status_size;
1697
1698                 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1699                 if (!phdr4note)
1700                         goto end_coredump;
1701
1702                 fill_elf_note_phdr(phdr4note, sz, offset);
1703                 offset += sz;
1704         }
1705
1706         /* Page-align dumped data */
1707         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1708
1709         offset += elf_core_vma_data_size(cprm->mm_flags);
1710         offset += elf_core_extra_data_size();
1711         e_shoff = offset;
1712
1713         if (e_phnum == PN_XNUM) {
1714                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1715                 if (!shdr4extnum)
1716                         goto end_coredump;
1717                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1718         }
1719
1720         offset = dataoff;
1721
1722         if (!dump_emit(cprm, elf, sizeof(*elf)))
1723                 goto end_coredump;
1724
1725         if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
1726                 goto end_coredump;
1727
1728         /* write program headers for segments dump */
1729         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1730                 struct elf_phdr phdr;
1731                 size_t sz;
1732
1733                 sz = vma->vm_end - vma->vm_start;
1734
1735                 phdr.p_type = PT_LOAD;
1736                 phdr.p_offset = offset;
1737                 phdr.p_vaddr = vma->vm_start;
1738                 phdr.p_paddr = 0;
1739                 phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
1740                 phdr.p_memsz = sz;
1741                 offset += phdr.p_filesz;
1742                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1743                 if (vma->vm_flags & VM_WRITE)
1744                         phdr.p_flags |= PF_W;
1745                 if (vma->vm_flags & VM_EXEC)
1746                         phdr.p_flags |= PF_X;
1747                 phdr.p_align = ELF_EXEC_PAGESIZE;
1748
1749                 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
1750                         goto end_coredump;
1751         }
1752
1753         if (!elf_core_write_extra_phdrs(cprm, offset))
1754                 goto end_coredump;
1755
1756         /* write out the notes section */
1757         for (i = 0; i < numnote; i++)
1758                 if (!writenote(notes + i, cprm))
1759                         goto end_coredump;
1760
1761         /* write out the thread status notes section */
1762         list_for_each(t, &thread_list) {
1763                 struct elf_thread_status *tmp =
1764                                 list_entry(t, struct elf_thread_status, list);
1765
1766                 for (i = 0; i < tmp->num_notes; i++)
1767                         if (!writenote(&tmp->notes[i], cprm))
1768                                 goto end_coredump;
1769         }
1770
1771         if (!dump_skip(cprm, dataoff - cprm->pos))
1772                 goto end_coredump;
1773
1774         if (!elf_fdpic_dump_segments(cprm))
1775                 goto end_coredump;
1776
1777         if (!elf_core_write_extra_data(cprm))
1778                 goto end_coredump;
1779
1780         if (e_phnum == PN_XNUM) {
1781                 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
1782                         goto end_coredump;
1783         }
1784
1785         if (cprm->file->f_pos != offset) {
1786                 /* Sanity check */
1787                 printk(KERN_WARNING
1788                        "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1789                        cprm->file->f_pos, offset);
1790         }
1791
1792 end_coredump:
1793         while (!list_empty(&thread_list)) {
1794                 struct list_head *tmp = thread_list.next;
1795                 list_del(tmp);
1796                 kfree(list_entry(tmp, struct elf_thread_status, list));
1797         }
1798         kfree(phdr4note);
1799         kfree(elf);
1800         kfree(prstatus);
1801         kfree(psinfo);
1802         kfree(notes);
1803         kfree(fpu);
1804         kfree(shdr4extnum);
1805 #ifdef ELF_CORE_COPY_XFPREGS
1806         kfree(xfpu);
1807 #endif
1808         return has_dumped;
1809 #undef NUM_NOTES
1810 }
1811
1812 #endif          /* CONFIG_ELF_CORE */