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 = flush_old_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         install_exec_creds(bprm);
 438         if (create_elf_fdpic_tables(bprm, current->mm,
 439                                     &exec_params, &interp_params) < 0)
 440                 goto error;
 441
 442         kdebug("- start_code  %lx", current->mm->start_code);
 443         kdebug("- end_code    %lx", current->mm->end_code);
 444         kdebug("- start_data  %lx", current->mm->start_data);
 445         kdebug("- end_data    %lx", current->mm->end_data);
 446         kdebug("- start_brk   %lx", current->mm->start_brk);
 447         kdebug("- brk         %lx", current->mm->brk);
 448         kdebug("- start_stack %lx", current->mm->start_stack);
 449
 450 #ifdef ELF_FDPIC_PLAT_INIT
 451         /*
 452          * The ABI may specify that certain registers be set up in special
 453          * ways (on i386 %edx is the address of a DT_FINI function, for
 454          * example.  This macro performs whatever initialization to
 455          * the regs structure is required.
 456          */
 457         dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
 458         ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
 459                             dynaddr);
 460 #endif
 461
 462         finalize_exec(bprm);
 463         /* everything is now ready... get the userspace context ready to roll */
 464         entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
 465         start_thread(regs, entryaddr, current->mm->start_stack);
 466
 467         retval = 0;
 468
 469 error:
 470         if (interpreter) {
 471                 allow_write_access(interpreter);
 472                 fput(interpreter);
 473         }
 474         kfree(interpreter_name);
 475         kfree(exec_params.phdrs);
 476         kfree(exec_params.loadmap);
 477         kfree(interp_params.phdrs);
 478         kfree(interp_params.loadmap);
 479         return retval;
 480 }
 481
 482 /*****************************************************************************/
 483
 484 #ifndef ELF_BASE_PLATFORM
 485 /*
 486  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 487  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 488  * will be copied to the user stack in the same manner as AT_PLATFORM.
 489  */
 490 #define ELF_BASE_PLATFORM NULL
 491 #endif
 492
 493 /*
 494  * present useful information to the program by shovelling it onto the new
 495  * process's stack
 496  */
 497 static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 498                                    struct mm_struct *mm,
 499                                    struct elf_fdpic_params *exec_params,
 500                                    struct elf_fdpic_params *interp_params)
 501 {
 502         const struct cred *cred = current_cred();
 503         unsigned long sp, csp, nitems;
 504         elf_caddr_t __user *argv, *envp;
 505         size_t platform_len = 0, len;
 506         char *k_platform, *k_base_platform;
 507         char __user *u_platform, *u_base_platform, *p;
 508         int loop;
 509         int nr; /* reset for each csp adjustment */
 510
 511 #ifdef CONFIG_MMU
 512         /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
 513          * by the processes running on the same package. One thing we can do is
 514          * to shuffle the initial stack for them, so we give the architecture
 515          * an opportunity to do so here.
 516          */
 517         sp = arch_align_stack(bprm->p);
 518 #else
 519         sp = mm->start_stack;
 520
 521         /* stack the program arguments and environment */
 522         if (transfer_args_to_stack(bprm, &sp) < 0)
 523                 return -EFAULT;
 524         sp &= ~15;
 525 #endif
 526
 527         /*
 528          * If this architecture has a platform capability string, copy it
 529          * to userspace.  In some cases (Sparc), this info is impossible
 530          * for userspace to get any other way, in others (i386) it is
 531          * merely difficult.
 532          */
 533         k_platform = ELF_PLATFORM;
 534         u_platform = NULL;
 535
 536         if (k_platform) {
 537                 platform_len = strlen(k_platform) + 1;
 538                 sp -= platform_len;
 539                 u_platform = (char __user *) sp;
 540                 if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
 541                         return -EFAULT;
 542         }
 543
 544         /*
 545          * If this architecture has a "base" platform capability
 546          * string, copy it to userspace.
 547          */
 548         k_base_platform = ELF_BASE_PLATFORM;
 549         u_base_platform = NULL;
 550
 551         if (k_base_platform) {
 552                 platform_len = strlen(k_base_platform) + 1;
 553                 sp -= platform_len;
 554                 u_base_platform = (char __user *) sp;
 555                 if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
 556                         return -EFAULT;
 557         }
 558
 559         sp &= ~7UL;
 560
 561         /* stack the load map(s) */
 562         len = sizeof(struct elf32_fdpic_loadmap);
 563         len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
 564         sp = (sp - len) & ~7UL;
 565         exec_params->map_addr = sp;
 566
 567         if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
 568                 return -EFAULT;
 569
 570         current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
 571
 572         if (interp_params->loadmap) {
 573                 len = sizeof(struct elf32_fdpic_loadmap);
 574                 len += sizeof(struct elf32_fdpic_loadseg) *
 575                         interp_params->loadmap->nsegs;
 576                 sp = (sp - len) & ~7UL;
 577                 interp_params->map_addr = sp;
 578
 579                 if (copy_to_user((void __user *) sp, interp_params->loadmap,
 580                                  len) != 0)
 581                         return -EFAULT;
 582
 583                 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
 584         }
 585
 586         /* force 16 byte _final_ alignment here for generality */
 587 #define DLINFO_ITEMS 15
 588
 589         nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
 590                 (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
 591
 592         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
 593                 nitems++;
 594
 595         csp = sp;
 596         sp -= nitems * 2 * sizeof(unsigned long);
 597         sp -= (bprm->envc + 1) * sizeof(char *);        /* envv[] */
 598         sp -= (bprm->argc + 1) * sizeof(char *);        /* argv[] */
 599         sp -= 1 * sizeof(unsigned long);                /* argc */
 600
 601         csp -= sp & 15UL;
 602         sp -= sp & 15UL;
 603
 604         /* put the ELF interpreter info on the stack */
 605 #define NEW_AUX_ENT(id, val)                                            \
 606         do {                                                            \
 607                 struct { unsigned long _id, _val; } __user *ent;        \
 608                                                                         \
 609                 ent = (void __user *) csp;                              \
 610                 __put_user((id), &ent[nr]._id);                         \
 611                 __put_user((val), &ent[nr]._val);                       \
 612                 nr++;                                                   \
 613         } while (0)
 614
 615         nr = 0;
 616         csp -= 2 * sizeof(unsigned long);
 617         NEW_AUX_ENT(AT_NULL, 0);
 618         if (k_platform) {
 619                 nr = 0;
 620                 csp -= 2 * sizeof(unsigned long);
 621                 NEW_AUX_ENT(AT_PLATFORM,
 622                             (elf_addr_t) (unsigned long) u_platform);
 623         }
 624
 625         if (k_base_platform) {
 626                 nr = 0;
 627                 csp -= 2 * sizeof(unsigned long);
 628                 NEW_AUX_ENT(AT_BASE_PLATFORM,
 629                             (elf_addr_t) (unsigned long) u_base_platform);
 630         }
 631
 632         if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
 633                 nr = 0;
 634                 csp -= 2 * sizeof(unsigned long);
 635                 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
 636         }
 637
 638         nr = 0;
 639         csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
 640         NEW_AUX_ENT(AT_HWCAP,   ELF_HWCAP);
 641 #ifdef ELF_HWCAP2
 642         NEW_AUX_ENT(AT_HWCAP2,  ELF_HWCAP2);
 643 #endif
 644         NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
 645         NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
 646         NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
 647         NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
 648         NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
 649         NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
 650         NEW_AUX_ENT(AT_FLAGS,   0);
 651         NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
 652         NEW_AUX_ENT(AT_UID,     (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
 653         NEW_AUX_ENT(AT_EUID,    (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
 654         NEW_AUX_ENT(AT_GID,     (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
 655         NEW_AUX_ENT(AT_EGID,    (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
 656         NEW_AUX_ENT(AT_SECURE,  bprm->secureexec);
 657         NEW_AUX_ENT(AT_EXECFN,  bprm->exec);
 658
 659 #ifdef ARCH_DLINFO
 660         nr = 0;
 661         csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
 662
 663         /* ARCH_DLINFO must come last so platform specific code can enforce
 664          * special alignment requirements on the AUXV if necessary (eg. PPC).
 665          */
 666         ARCH_DLINFO;
 667 #endif
 668 #undef NEW_AUX_ENT
 669
 670         /* allocate room for argv[] and envv[] */
 671         csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 672         envp = (elf_caddr_t __user *) csp;
 673         csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
 674         argv = (elf_caddr_t __user *) csp;
 675
 676         /* stack argc */
 677         csp -= sizeof(unsigned long);
 678         __put_user(bprm->argc, (unsigned long __user *) csp);
 679
 680         BUG_ON(csp != sp);
 681
 682         /* fill in the argv[] array */
 683 #ifdef CONFIG_MMU
 684         current->mm->arg_start = bprm->p;
 685 #else
 686         current->mm->arg_start = current->mm->start_stack -
 687                 (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
 688 #endif
 689
 690         p = (char __user *) current->mm->arg_start;
 691         for (loop = bprm->argc; loop > 0; loop--) {
 692                 __put_user((elf_caddr_t) p, argv++);
 693                 len = strnlen_user(p, MAX_ARG_STRLEN);
 694                 if (!len || len > MAX_ARG_STRLEN)
 695                         return -EINVAL;
 696                 p += len;
 697         }
 698         __put_user(NULL, argv);
 699         current->mm->arg_end = (unsigned long) p;
 700
 701         /* fill in the envv[] array */
 702         current->mm->env_start = (unsigned long) p;
 703         for (loop = bprm->envc; loop > 0; loop--) {
 704                 __put_user((elf_caddr_t)(unsigned long) p, envp++);
 705                 len = strnlen_user(p, MAX_ARG_STRLEN);
 706                 if (!len || len > MAX_ARG_STRLEN)
 707                         return -EINVAL;
 708                 p += len;
 709         }
 710         __put_user(NULL, envp);
 711         current->mm->env_end = (unsigned long) p;
 712
 713         mm->start_stack = (unsigned long) sp;
 714         return 0;
 715 }
 716
 717 /*****************************************************************************/
 718 /*
 719  * load the appropriate binary image (executable or interpreter) into memory
 720  * - we assume no MMU is available
 721  * - if no other PIC bits are set in params->hdr->e_flags
 722  *   - we assume that the LOADable segments in the binary are independently relocatable
 723  *   - we assume R/O executable segments are shareable
 724  * - else
 725  *   - we assume the loadable parts of the image to require fixed displacement
 726  *   - the image is not shareable
 727  */
 728 static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 729                               struct file *file,
 730                               struct mm_struct *mm,
 731                               const char *what)
 732 {
 733         struct elf32_fdpic_loadmap *loadmap;
 734 #ifdef CONFIG_MMU
 735         struct elf32_fdpic_loadseg *mseg;
 736 #endif
 737         struct elf32_fdpic_loadseg *seg;
 738         struct elf32_phdr *phdr;
 739         unsigned long load_addr, stop;
 740         unsigned nloads, tmp;
 741         size_t size;
 742         int loop, ret;
 743
 744         /* allocate a load map table */
 745         nloads = 0;
 746         for (loop = 0; loop < params->hdr.e_phnum; loop++)
 747                 if (params->phdrs[loop].p_type == PT_LOAD)
 748                         nloads++;
 749
 750         if (nloads == 0)
 751                 return -ELIBBAD;
 752
 753         size = sizeof(*loadmap) + nloads * sizeof(*seg);
 754         loadmap = kzalloc(size, GFP_KERNEL);
 755         if (!loadmap)
 756                 return -ENOMEM;
 757
 758         params->loadmap = loadmap;
 759
 760         loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
 761         loadmap->nsegs = nloads;
 762
 763         load_addr = params->load_addr;
 764         seg = loadmap->segs;
 765
 766         /* map the requested LOADs into the memory space */
 767         switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
 768         case ELF_FDPIC_FLAG_CONSTDISP:
 769         case ELF_FDPIC_FLAG_CONTIGUOUS:
 770 #ifndef CONFIG_MMU
 771                 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
 772                 if (ret < 0)
 773                         return ret;
 774                 break;
 775 #endif
 776         default:
 777                 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
 778                 if (ret < 0)
 779                         return ret;
 780                 break;
 781         }
 782
 783         /* map the entry point */
 784         if (params->hdr.e_entry) {
 785                 seg = loadmap->segs;
 786                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 787                         if (params->hdr.e_entry >= seg->p_vaddr &&
 788                             params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
 789                                 params->entry_addr =
 790                                         (params->hdr.e_entry - seg->p_vaddr) +
 791                                         seg->addr;
 792                                 break;
 793                         }
 794                 }
 795         }
 796
 797         /* determine where the program header table has wound up if mapped */
 798         stop = params->hdr.e_phoff;
 799         stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
 800         phdr = params->phdrs;
 801
 802         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 803                 if (phdr->p_type != PT_LOAD)
 804                         continue;
 805
 806                 if (phdr->p_offset > params->hdr.e_phoff ||
 807                     phdr->p_offset + phdr->p_filesz < stop)
 808                         continue;
 809
 810                 seg = loadmap->segs;
 811                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 812                         if (phdr->p_vaddr >= seg->p_vaddr &&
 813                             phdr->p_vaddr + phdr->p_filesz <=
 814                             seg->p_vaddr + seg->p_memsz) {
 815                                 params->ph_addr =
 816                                         (phdr->p_vaddr - seg->p_vaddr) +
 817                                         seg->addr +
 818                                         params->hdr.e_phoff - phdr->p_offset;
 819                                 break;
 820                         }
 821                 }
 822                 break;
 823         }
 824
 825         /* determine where the dynamic section has wound up if there is one */
 826         phdr = params->phdrs;
 827         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 828                 if (phdr->p_type != PT_DYNAMIC)
 829                         continue;
 830
 831                 seg = loadmap->segs;
 832                 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
 833                         if (phdr->p_vaddr >= seg->p_vaddr &&
 834                             phdr->p_vaddr + phdr->p_memsz <=
 835                             seg->p_vaddr + seg->p_memsz) {
 836                                 Elf32_Dyn __user *dyn;
 837                                 Elf32_Sword d_tag;
 838
 839                                 params->dynamic_addr =
 840                                         (phdr->p_vaddr - seg->p_vaddr) +
 841                                         seg->addr;
 842
 843                                 /* check the dynamic section contains at least
 844                                  * one item, and that the last item is a NULL
 845                                  * entry */
 846                                 if (phdr->p_memsz == 0 ||
 847                                     phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
 848                                         goto dynamic_error;
 849
 850                                 tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
 851                                 dyn = (Elf32_Dyn __user *)params->dynamic_addr;
 852                                 __get_user(d_tag, &dyn[tmp - 1].d_tag);
 853                                 if (d_tag != 0)
 854                                         goto dynamic_error;
 855                                 break;
 856                         }
 857                 }
 858                 break;
 859         }
 860
 861         /* now elide adjacent segments in the load map on MMU linux
 862          * - on uClinux the holes between may actually be filled with system
 863          *   stuff or stuff from other processes
 864          */
 865 #ifdef CONFIG_MMU
 866         nloads = loadmap->nsegs;
 867         mseg = loadmap->segs;
 868         seg = mseg + 1;
 869         for (loop = 1; loop < nloads; loop++) {
 870                 /* see if we have a candidate for merging */
 871                 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
 872                         load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
 873                         if (load_addr == (seg->addr & PAGE_MASK)) {
 874                                 mseg->p_memsz +=
 875                                         load_addr -
 876                                         (mseg->addr + mseg->p_memsz);
 877                                 mseg->p_memsz += seg->addr & ~PAGE_MASK;
 878                                 mseg->p_memsz += seg->p_memsz;
 879                                 loadmap->nsegs--;
 880                                 continue;
 881                         }
 882                 }
 883
 884                 mseg++;
 885                 if (mseg != seg)
 886                         *mseg = *seg;
 887         }
 888 #endif
 889
 890         kdebug("Mapped Object [%s]:", what);
 891         kdebug("- elfhdr   : %lx", params->elfhdr_addr);
 892         kdebug("- entry    : %lx", params->entry_addr);
 893         kdebug("- PHDR[]   : %lx", params->ph_addr);
 894         kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
 895         seg = loadmap->segs;
 896         for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
 897                 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
 898                        loop,
 899                        seg->addr, seg->addr + seg->p_memsz - 1,
 900                        seg->p_vaddr, seg->p_memsz);
 901
 902         return 0;
 903
 904 dynamic_error:
 905         printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
 906                what, file_inode(file)->i_ino);
 907         return -ELIBBAD;
 908 }
 909
 910 /*****************************************************************************/
 911 /*
 912  * map a file with constant displacement under uClinux
 913  */
 914 #ifndef CONFIG_MMU
 915 static int elf_fdpic_map_file_constdisp_on_uclinux(
 916         struct elf_fdpic_params *params,
 917         struct file *file,
 918         struct mm_struct *mm)
 919 {
 920         struct elf32_fdpic_loadseg *seg;
 921         struct elf32_phdr *phdr;
 922         unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
 923         int loop, ret;
 924
 925         load_addr = params->load_addr;
 926         seg = params->loadmap->segs;
 927
 928         /* determine the bounds of the contiguous overall allocation we must
 929          * make */
 930         phdr = params->phdrs;
 931         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 932                 if (params->phdrs[loop].p_type != PT_LOAD)
 933                         continue;
 934
 935                 if (base > phdr->p_vaddr)
 936                         base = phdr->p_vaddr;
 937                 if (top < phdr->p_vaddr + phdr->p_memsz)
 938                         top = phdr->p_vaddr + phdr->p_memsz;
 939         }
 940
 941         /* allocate one big anon block for everything */
 942         mflags = MAP_PRIVATE;
 943         if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
 944                 mflags |= MAP_EXECUTABLE;
 945
 946         maddr = vm_mmap(NULL, load_addr, top - base,
 947                         PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
 948         if (IS_ERR_VALUE(maddr))
 949                 return (int) maddr;
 950
 951         if (load_addr != 0)
 952                 load_addr += PAGE_ALIGN(top - base);
 953
 954         /* and then load the file segments into it */
 955         phdr = params->phdrs;
 956         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
 957                 if (params->phdrs[loop].p_type != PT_LOAD)
 958                         continue;
 959
 960                 seg->addr = maddr + (phdr->p_vaddr - base);
 961                 seg->p_vaddr = phdr->p_vaddr;
 962                 seg->p_memsz = phdr->p_memsz;
 963
 964                 ret = read_code(file, seg->addr, phdr->p_offset,
 965                                        phdr->p_filesz);
 966                 if (ret < 0)
 967                         return ret;
 968
 969                 /* map the ELF header address if in this segment */
 970                 if (phdr->p_offset == 0)
 971                         params->elfhdr_addr = seg->addr;
 972
 973                 /* clear any space allocated but not loaded */
 974                 if (phdr->p_filesz < phdr->p_memsz) {
 975                         if (clear_user((void *) (seg->addr + phdr->p_filesz),
 976                                        phdr->p_memsz - phdr->p_filesz))
 977                                 return -EFAULT;
 978                 }
 979
 980                 if (mm) {
 981                         if (phdr->p_flags & PF_X) {
 982                                 if (!mm->start_code) {
 983                                         mm->start_code = seg->addr;
 984                                         mm->end_code = seg->addr +
 985                                                 phdr->p_memsz;
 986                                 }
 987                         } else if (!mm->start_data) {
 988                                 mm->start_data = seg->addr;
 989                                 mm->end_data = seg->addr + phdr->p_memsz;
 990                         }
 991                 }
 992
 993                 seg++;
 994         }
 995
 996         return 0;
 997 }
 998 #endif
 999
1000 /*****************************************************************************/
1001 /*
1002  * map a binary by direct mmap() of the individual PT_LOAD segments
1003  */
1004 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
1005                                              struct file *file,
1006                                              struct mm_struct *mm)
1007 {
1008         struct elf32_fdpic_loadseg *seg;
1009         struct elf32_phdr *phdr;
1010         unsigned long load_addr, delta_vaddr;
1011         int loop, dvset;
1012
1013         load_addr = params->load_addr;
1014         delta_vaddr = 0;
1015         dvset = 0;
1016
1017         seg = params->loadmap->segs;
1018
1019         /* deal with each load segment separately */
1020         phdr = params->phdrs;
1021         for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
1022                 unsigned long maddr, disp, excess, excess1;
1023                 int prot = 0, flags;
1024
1025                 if (phdr->p_type != PT_LOAD)
1026                         continue;
1027
1028                 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
1029                        (unsigned long) phdr->p_vaddr,
1030                        (unsigned long) phdr->p_offset,
1031                        (unsigned long) phdr->p_filesz,
1032                        (unsigned long) phdr->p_memsz);
1033
1034                 /* determine the mapping parameters */
1035                 if (phdr->p_flags & PF_R) prot |= PROT_READ;
1036                 if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
1037                 if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
1038
1039                 flags = MAP_PRIVATE | MAP_DENYWRITE;
1040                 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
1041                         flags |= MAP_EXECUTABLE;
1042
1043                 maddr = 0;
1044
1045                 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
1046                 case ELF_FDPIC_FLAG_INDEPENDENT:
1047                         /* PT_LOADs are independently locatable */
1048                         break;
1049
1050                 case ELF_FDPIC_FLAG_HONOURVADDR:
1051                         /* the specified virtual address must be honoured */
1052                         maddr = phdr->p_vaddr;
1053                         flags |= MAP_FIXED;
1054                         break;
1055
1056                 case ELF_FDPIC_FLAG_CONSTDISP:
1057                         /* constant displacement
1058                          * - can be mapped anywhere, but must be mapped as a
1059                          *   unit
1060                          */
1061                         if (!dvset) {
1062                                 maddr = load_addr;
1063                                 delta_vaddr = phdr->p_vaddr;
1064                                 dvset = 1;
1065                         } else {
1066                                 maddr = load_addr + phdr->p_vaddr - delta_vaddr;
1067                                 flags |= MAP_FIXED;
1068                         }
1069                         break;
1070
1071                 case ELF_FDPIC_FLAG_CONTIGUOUS:
1072                         /* contiguity handled later */
1073                         break;
1074
1075                 default:
1076                         BUG();
1077                 }
1078
1079                 maddr &= PAGE_MASK;
1080
1081                 /* create the mapping */
1082                 disp = phdr->p_vaddr & ~PAGE_MASK;
1083                 maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
1084                                 phdr->p_offset - disp);
1085
1086                 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
1087                        loop, phdr->p_memsz + disp, prot, flags,
1088                        phdr->p_offset - disp, maddr);
1089
1090                 if (IS_ERR_VALUE(maddr))
1091                         return (int) maddr;
1092
1093                 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
1094                     ELF_FDPIC_FLAG_CONTIGUOUS)
1095                         load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
1096
1097                 seg->addr = maddr + disp;
1098                 seg->p_vaddr = phdr->p_vaddr;
1099                 seg->p_memsz = phdr->p_memsz;
1100
1101                 /* map the ELF header address if in this segment */
1102                 if (phdr->p_offset == 0)
1103                         params->elfhdr_addr = seg->addr;
1104
1105                 /* clear the bit between beginning of mapping and beginning of
1106                  * PT_LOAD */
1107                 if (prot & PROT_WRITE && disp > 0) {
1108                         kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
1109                         if (clear_user((void __user *) maddr, disp))
1110                                 return -EFAULT;
1111                         maddr += disp;
1112                 }
1113
1114                 /* clear any space allocated but not loaded
1115                  * - on uClinux we can just clear the lot
1116                  * - on MMU linux we'll get a SIGBUS beyond the last page
1117                  *   extant in the file
1118                  */
1119                 excess = phdr->p_memsz - phdr->p_filesz;
1120                 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
1121
1122 #ifdef CONFIG_MMU
1123                 if (excess > excess1) {
1124                         unsigned long xaddr = maddr + phdr->p_filesz + excess1;
1125                         unsigned long xmaddr;
1126
1127                         flags |= MAP_FIXED | MAP_ANONYMOUS;
1128                         xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
1129                                          prot, flags, 0);
1130
1131                         kdebug("mmap[%d] <anon>"
1132                                " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
1133                                loop, xaddr, excess - excess1, prot, flags,
1134                                xmaddr);
1135
1136                         if (xmaddr != xaddr)
1137                                 return -ENOMEM;
1138                 }
1139
1140                 if (prot & PROT_WRITE && excess1 > 0) {
1141                         kdebug("clear[%d] ad=%lx sz=%lx",
1142                                loop, maddr + phdr->p_filesz, excess1);
1143                         if (clear_user((void __user *) maddr + phdr->p_filesz,
1144                                        excess1))
1145                                 return -EFAULT;
1146                 }
1147
1148 #else
1149                 if (excess > 0) {
1150                         kdebug("clear[%d] ad=%lx sz=%lx",
1151                                loop, maddr + phdr->p_filesz, excess);
1152                         if (clear_user((void *) maddr + phdr->p_filesz, excess))
1153                                 return -EFAULT;
1154                 }
1155 #endif
1156
1157                 if (mm) {
1158                         if (phdr->p_flags & PF_X) {
1159                                 if (!mm->start_code) {
1160                                         mm->start_code = maddr;
1161                                         mm->end_code = maddr + phdr->p_memsz;
1162                                 }
1163                         } else if (!mm->start_data) {
1164                                 mm->start_data = maddr;
1165                                 mm->end_data = maddr + phdr->p_memsz;
1166                         }
1167                 }
1168
1169                 seg++;
1170         }
1171
1172         return 0;
1173 }
1174
1175 /*****************************************************************************/
1176 /*
1177  * ELF-FDPIC core dumper
1178  *
1179  * Modelled on fs/exec.c:aout_core_dump()
1180  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1181  *
1182  * Modelled on fs/binfmt_elf.c core dumper
1183  */
1184 #ifdef CONFIG_ELF_CORE
1185
1186 /*
1187  * Decide whether a segment is worth dumping; default is yes to be
1188  * sure (missing info is worse than too much; etc).
1189  * Personally I'd include everything, and use the coredump limit...
1190  *
1191  * I think we should skip something. But I am not sure how. H.J.
1192  */
1193 static int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
1194 {
1195         int dump_ok;
1196
1197         /* Do not dump I/O mapped devices or special mappings */
1198         if (vma->vm_flags & VM_IO) {
1199                 kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
1200                 return 0;
1201         }
1202
1203         /* If we may not read the contents, don't allow us to dump
1204          * them either. "dump_write()" can't handle it anyway.
1205          */
1206         if (!(vma->vm_flags & VM_READ)) {
1207                 kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
1208                 return 0;
1209         }
1210
1211         /* support for DAX */
1212         if (vma_is_dax(vma)) {
1213                 if (vma->vm_flags & VM_SHARED) {
1214                         dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags);
1215                         kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start,
1216                                vma->vm_flags, dump_ok ? "yes" : "no");
1217                 } else {
1218                         dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags);
1219                         kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start,
1220                                vma->vm_flags, dump_ok ? "yes" : "no");
1221                 }
1222                 return dump_ok;
1223         }
1224
1225         /* By default, dump shared memory if mapped from an anonymous file. */
1226         if (vma->vm_flags & VM_SHARED) {
1227                 if (file_inode(vma->vm_file)->i_nlink == 0) {
1228                         dump_ok = test_bit(MMF_DUMP_ANON_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                 dump_ok = test_bit(MMF_DUMP_MAPPED_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 #ifdef CONFIG_MMU
1241         /* By default, if it hasn't been written to, don't write it out */
1242         if (!vma->anon_vma) {
1243                 dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
1244                 kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
1245                        vma->vm_flags, dump_ok ? "yes" : "no");
1246                 return dump_ok;
1247         }
1248 #endif
1249
1250         dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
1251         kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
1252                dump_ok ? "yes" : "no");
1253         return dump_ok;
1254 }
1255
1256 /* An ELF note in memory */
1257 struct memelfnote
1258 {
1259         const char *name;
1260         int type;
1261         unsigned int datasz;
1262         void *data;
1263 };
1264
1265 static int notesize(struct memelfnote *en)
1266 {
1267         int sz;
1268
1269         sz = sizeof(struct elf_note);
1270         sz += roundup(strlen(en->name) + 1, 4);
1271         sz += roundup(en->datasz, 4);
1272
1273         return sz;
1274 }
1275
1276 /* #define DEBUG */
1277
1278 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1279 {
1280         struct elf_note en;
1281         en.n_namesz = strlen(men->name) + 1;
1282         en.n_descsz = men->datasz;
1283         en.n_type = men->type;
1284
1285         return dump_emit(cprm, &en, sizeof(en)) &&
1286                 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1287                 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1288 }
1289
1290 static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
1291 {
1292         memcpy(elf->e_ident, ELFMAG, SELFMAG);
1293         elf->e_ident[EI_CLASS] = ELF_CLASS;
1294         elf->e_ident[EI_DATA] = ELF_DATA;
1295         elf->e_ident[EI_VERSION] = EV_CURRENT;
1296         elf->e_ident[EI_OSABI] = ELF_OSABI;
1297         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
1298
1299         elf->e_type = ET_CORE;
1300         elf->e_machine = ELF_ARCH;
1301         elf->e_version = EV_CURRENT;
1302         elf->e_entry = 0;
1303         elf->e_phoff = sizeof(struct elfhdr);
1304         elf->e_shoff = 0;
1305         elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
1306         elf->e_ehsize = sizeof(struct elfhdr);
1307         elf->e_phentsize = sizeof(struct elf_phdr);
1308         elf->e_phnum = segs;
1309         elf->e_shentsize = 0;
1310         elf->e_shnum = 0;
1311         elf->e_shstrndx = 0;
1312         return;
1313 }
1314
1315 static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1316 {
1317         phdr->p_type = PT_NOTE;
1318         phdr->p_offset = offset;
1319         phdr->p_vaddr = 0;
1320         phdr->p_paddr = 0;
1321         phdr->p_filesz = sz;
1322         phdr->p_memsz = 0;
1323         phdr->p_flags = 0;
1324         phdr->p_align = 0;
1325         return;
1326 }
1327
1328 static inline void fill_note(struct memelfnote *note, const char *name, int type,
1329                 unsigned int sz, void *data)
1330 {
1331         note->name = name;
1332         note->type = type;
1333         note->datasz = sz;
1334         note->data = data;
1335         return;
1336 }
1337
1338 /*
1339  * fill up all the fields in prstatus from the given task struct, except
1340  * registers which need to be filled up separately.
1341  */
1342 static void fill_prstatus(struct elf_prstatus *prstatus,
1343                           struct task_struct *p, long signr)
1344 {
1345         prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1346         prstatus->pr_sigpend = p->pending.signal.sig[0];
1347         prstatus->pr_sighold = p->blocked.sig[0];
1348         rcu_read_lock();
1349         prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1350         rcu_read_unlock();
1351         prstatus->pr_pid = task_pid_vnr(p);
1352         prstatus->pr_pgrp = task_pgrp_vnr(p);
1353         prstatus->pr_sid = task_session_vnr(p);
1354         if (thread_group_leader(p)) {
1355                 struct task_cputime cputime;
1356
1357                 /*
1358                  * This is the record for the group leader.  It shows the
1359                  * group-wide total, not its individual thread total.
1360                  */
1361                 thread_group_cputime(p, &cputime);
1362                 prstatus->pr_utime = ns_to_timeval(cputime.utime);
1363                 prstatus->pr_stime = ns_to_timeval(cputime.stime);
1364         } else {
1365                 u64 utime, stime;
1366
1367                 task_cputime(p, &utime, &stime);
1368                 prstatus->pr_utime = ns_to_timeval(utime);
1369                 prstatus->pr_stime = ns_to_timeval(stime);
1370         }
1371         prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
1372         prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
1373
1374         prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1375         prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
1376 }
1377
1378 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1379                        struct mm_struct *mm)
1380 {
1381         const struct cred *cred;
1382         unsigned int i, len;
1383
1384         /* first copy the parameters from user space */
1385         memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1386
1387         len = mm->arg_end - mm->arg_start;
1388         if (len >= ELF_PRARGSZ)
1389                 len = ELF_PRARGSZ - 1;
1390         if (copy_from_user(&psinfo->pr_psargs,
1391                            (const char __user *) mm->arg_start, len))
1392                 return -EFAULT;
1393         for (i = 0; i < len; i++)
1394                 if (psinfo->pr_psargs[i] == 0)
1395                         psinfo->pr_psargs[i] = ' ';
1396         psinfo->pr_psargs[len] = 0;
1397
1398         rcu_read_lock();
1399         psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1400         rcu_read_unlock();
1401         psinfo->pr_pid = task_pid_vnr(p);
1402         psinfo->pr_pgrp = task_pgrp_vnr(p);
1403         psinfo->pr_sid = task_session_vnr(p);
1404
1405         i = p->state ? ffz(~p->state) + 1 : 0;
1406         psinfo->pr_state = i;
1407         psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1408         psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1409         psinfo->pr_nice = task_nice(p);
1410         psinfo->pr_flag = p->flags;
1411         rcu_read_lock();
1412         cred = __task_cred(p);
1413         SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1414         SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1415         rcu_read_unlock();
1416         strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1417
1418         return 0;
1419 }
1420
1421 /* Here is the structure in which status of each thread is captured. */
1422 struct elf_thread_status
1423 {
1424         struct list_head list;
1425         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
1426         elf_fpregset_t fpu;             /* NT_PRFPREG */
1427         struct task_struct *thread;
1428 #ifdef ELF_CORE_COPY_XFPREGS
1429         elf_fpxregset_t xfpu;           /* ELF_CORE_XFPREG_TYPE */
1430 #endif
1431         struct memelfnote notes[3];
1432         int num_notes;
1433 };
1434
1435 /*
1436  * In order to add the specific thread information for the elf file format,
1437  * we need to keep a linked list of every thread's pr_status and then create
1438  * a single section for them in the final core file.
1439  */
1440 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1441 {
1442         struct task_struct *p = t->thread;
1443         int sz = 0;
1444
1445         t->num_notes = 0;
1446
1447         fill_prstatus(&t->prstatus, p, signr);
1448         elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1449
1450         fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1451                   &t->prstatus);
1452         t->num_notes++;
1453         sz += notesize(&t->notes[0]);
1454
1455         t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
1456         if (t->prstatus.pr_fpvalid) {
1457                 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1458                           &t->fpu);
1459                 t->num_notes++;
1460                 sz += notesize(&t->notes[1]);
1461         }
1462
1463 #ifdef ELF_CORE_COPY_XFPREGS
1464         if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1465                 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1466                           sizeof(t->xfpu), &t->xfpu);
1467                 t->num_notes++;
1468                 sz += notesize(&t->notes[2]);
1469         }
1470 #endif
1471         return sz;
1472 }
1473
1474 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
1475                              elf_addr_t e_shoff, int segs)
1476 {
1477         elf->e_shoff = e_shoff;
1478         elf->e_shentsize = sizeof(*shdr4extnum);
1479         elf->e_shnum = 1;
1480         elf->e_shstrndx = SHN_UNDEF;
1481
1482         memset(shdr4extnum, 0, sizeof(*shdr4extnum));
1483
1484         shdr4extnum->sh_type = SHT_NULL;
1485         shdr4extnum->sh_size = elf->e_shnum;
1486         shdr4extnum->sh_link = elf->e_shstrndx;
1487         shdr4extnum->sh_info = segs;
1488 }
1489
1490 /*
1491  * dump the segments for an MMU process
1492  */
1493 static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
1494 {
1495         struct vm_area_struct *vma;
1496
1497         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1498 #ifdef CONFIG_MMU
1499                 unsigned long addr;
1500 #endif
1501
1502                 if (!maydump(vma, cprm->mm_flags))
1503                         continue;
1504
1505 #ifdef CONFIG_MMU
1506                 for (addr = vma->vm_start; addr < vma->vm_end;
1507                                                         addr += PAGE_SIZE) {
1508                         bool res;
1509                         struct page *page = get_dump_page(addr);
1510                         if (page) {
1511                                 void *kaddr = kmap(page);
1512                                 res = dump_emit(cprm, kaddr, PAGE_SIZE);
1513                                 kunmap(page);
1514                                 put_page(page);
1515                         } else {
1516                                 res = dump_skip(cprm, PAGE_SIZE);
1517                         }
1518                         if (!res)
1519                                 return false;
1520                 }
1521 #else
1522                 if (!dump_emit(cprm, (void *) vma->vm_start,
1523                                 vma->vm_end - vma->vm_start))
1524                         return false;
1525 #endif
1526         }
1527         return true;
1528 }
1529
1530 static size_t elf_core_vma_data_size(unsigned long mm_flags)
1531 {
1532         struct vm_area_struct *vma;
1533         size_t size = 0;
1534
1535         for (vma = current->mm->mmap; vma; vma = vma->vm_next)
1536                 if (maydump(vma, mm_flags))
1537                         size += vma->vm_end - vma->vm_start;
1538         return size;
1539 }
1540
1541 /*
1542  * Actual dumper
1543  *
1544  * This is a two-pass process; first we find the offsets of the bits,
1545  * and then they are actually written out.  If we run out of core limit
1546  * we just truncate.
1547  */
1548 static int elf_fdpic_core_dump(struct coredump_params *cprm)
1549 {
1550 #define NUM_NOTES       6
1551         int has_dumped = 0;
1552         mm_segment_t fs;
1553         int segs;
1554         int i;
1555         struct vm_area_struct *vma;
1556         struct elfhdr *elf = NULL;
1557         loff_t offset = 0, dataoff;
1558         int numnote;
1559         struct memelfnote *notes = NULL;
1560         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
1561         struct elf_prpsinfo *psinfo = NULL;     /* NT_PRPSINFO */
1562         LIST_HEAD(thread_list);
1563         struct list_head *t;
1564         elf_fpregset_t *fpu = NULL;
1565 #ifdef ELF_CORE_COPY_XFPREGS
1566         elf_fpxregset_t *xfpu = NULL;
1567 #endif
1568         int thread_status_size = 0;
1569         elf_addr_t *auxv;
1570         struct elf_phdr *phdr4note = NULL;
1571         struct elf_shdr *shdr4extnum = NULL;
1572         Elf_Half e_phnum;
1573         elf_addr_t e_shoff;
1574         struct core_thread *ct;
1575         struct elf_thread_status *tmp;
1576
1577         /*
1578          * We no longer stop all VM operations.
1579          *
1580          * This is because those proceses that could possibly change map_count
1581          * or the mmap / vma pages are now blocked in do_exit on current
1582          * finishing this core dump.
1583          *
1584          * Only ptrace can touch these memory addresses, but it doesn't change
1585          * the map_count or the pages allocated. So no possibility of crashing
1586          * exists while dumping the mm->vm_next areas to the core file.
1587          */
1588
1589         /* alloc memory for large data structures: too large to be on stack */
1590         elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1591         if (!elf)
1592                 goto cleanup;
1593         prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
1594         if (!prstatus)
1595                 goto cleanup;
1596         psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1597         if (!psinfo)
1598                 goto cleanup;
1599         notes = kmalloc_array(NUM_NOTES, sizeof(struct memelfnote),
1600                               GFP_KERNEL);
1601         if (!notes)
1602                 goto cleanup;
1603         fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
1604         if (!fpu)
1605                 goto cleanup;
1606 #ifdef ELF_CORE_COPY_XFPREGS
1607         xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
1608         if (!xfpu)
1609                 goto cleanup;
1610 #endif
1611
1612         for (ct = current->mm->core_state->dumper.next;
1613                                         ct; ct = ct->next) {
1614                 tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
1615                 if (!tmp)
1616                         goto cleanup;
1617
1618                 tmp->thread = ct->task;
1619                 list_add(&tmp->list, &thread_list);
1620         }
1621
1622         list_for_each(t, &thread_list) {
1623                 struct elf_thread_status *tmp;
1624                 int sz;
1625
1626                 tmp = list_entry(t, struct elf_thread_status, list);
1627                 sz = elf_dump_thread_status(cprm->siginfo->si_signo, tmp);
1628                 thread_status_size += sz;
1629         }
1630
1631         /* now collect the dump for the current */
1632         fill_prstatus(prstatus, current, cprm->siginfo->si_signo);
1633         elf_core_copy_regs(&prstatus->pr_reg, cprm->regs);
1634
1635         segs = current->mm->map_count;
1636         segs += elf_core_extra_phdrs();
1637
1638         /* for notes section */
1639         segs++;
1640
1641         /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
1642          * this, kernel supports extended numbering. Have a look at
1643          * include/linux/elf.h for further information. */
1644         e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
1645
1646         /* Set up header */
1647         fill_elf_fdpic_header(elf, e_phnum);
1648
1649         has_dumped = 1;
1650         /*
1651          * Set up the notes in similar form to SVR4 core dumps made
1652          * with info from their /proc.
1653          */
1654
1655         fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
1656         fill_psinfo(psinfo, current->group_leader, current->mm);
1657         fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1658
1659         numnote = 2;
1660
1661         auxv = (elf_addr_t *) current->mm->saved_auxv;
1662
1663         i = 0;
1664         do
1665                 i += 2;
1666         while (auxv[i - 2] != AT_NULL);
1667         fill_note(&notes[numnote++], "CORE", NT_AUXV,
1668                   i * sizeof(elf_addr_t), auxv);
1669
1670         /* Try to dump the FPU. */
1671         if ((prstatus->pr_fpvalid =
1672              elf_core_copy_task_fpregs(current, cprm->regs, fpu)))
1673                 fill_note(notes + numnote++,
1674                           "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
1675 #ifdef ELF_CORE_COPY_XFPREGS
1676         if (elf_core_copy_task_xfpregs(current, xfpu))
1677                 fill_note(notes + numnote++,
1678                           "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
1679 #endif
1680
1681         fs = get_fs();
1682         set_fs(KERNEL_DS);
1683
1684         offset += sizeof(*elf);                         /* Elf header */
1685         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
1686
1687         /* Write notes phdr entry */
1688         {
1689                 int sz = 0;
1690
1691                 for (i = 0; i < numnote; i++)
1692                         sz += notesize(notes + i);
1693
1694                 sz += thread_status_size;
1695
1696                 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
1697                 if (!phdr4note)
1698                         goto end_coredump;
1699
1700                 fill_elf_note_phdr(phdr4note, sz, offset);
1701                 offset += sz;
1702         }
1703
1704         /* Page-align dumped data */
1705         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1706
1707         offset += elf_core_vma_data_size(cprm->mm_flags);
1708         offset += elf_core_extra_data_size();
1709         e_shoff = offset;
1710
1711         if (e_phnum == PN_XNUM) {
1712                 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
1713                 if (!shdr4extnum)
1714                         goto end_coredump;
1715                 fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
1716         }
1717
1718         offset = dataoff;
1719
1720         if (!dump_emit(cprm, elf, sizeof(*elf)))
1721                 goto end_coredump;
1722
1723         if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
1724                 goto end_coredump;
1725
1726         /* write program headers for segments dump */
1727         for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
1728                 struct elf_phdr phdr;
1729                 size_t sz;
1730
1731                 sz = vma->vm_end - vma->vm_start;
1732
1733                 phdr.p_type = PT_LOAD;
1734                 phdr.p_offset = offset;
1735                 phdr.p_vaddr = vma->vm_start;
1736                 phdr.p_paddr = 0;
1737                 phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0;
1738                 phdr.p_memsz = sz;
1739                 offset += phdr.p_filesz;
1740                 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1741                 if (vma->vm_flags & VM_WRITE)
1742                         phdr.p_flags |= PF_W;
1743                 if (vma->vm_flags & VM_EXEC)
1744                         phdr.p_flags |= PF_X;
1745                 phdr.p_align = ELF_EXEC_PAGESIZE;
1746
1747                 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
1748                         goto end_coredump;
1749         }
1750
1751         if (!elf_core_write_extra_phdrs(cprm, offset))
1752                 goto end_coredump;
1753
1754         /* write out the notes section */
1755         for (i = 0; i < numnote; i++)
1756                 if (!writenote(notes + i, cprm))
1757                         goto end_coredump;
1758
1759         /* write out the thread status notes section */
1760         list_for_each(t, &thread_list) {
1761                 struct elf_thread_status *tmp =
1762                                 list_entry(t, struct elf_thread_status, list);
1763
1764                 for (i = 0; i < tmp->num_notes; i++)
1765                         if (!writenote(&tmp->notes[i], cprm))
1766                                 goto end_coredump;
1767         }
1768
1769         if (!dump_skip(cprm, dataoff - cprm->pos))
1770                 goto end_coredump;
1771
1772         if (!elf_fdpic_dump_segments(cprm))
1773                 goto end_coredump;
1774
1775         if (!elf_core_write_extra_data(cprm))
1776                 goto end_coredump;
1777
1778         if (e_phnum == PN_XNUM) {
1779                 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
1780                         goto end_coredump;
1781         }
1782
1783         if (cprm->file->f_pos != offset) {
1784                 /* Sanity check */
1785                 printk(KERN_WARNING
1786                        "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
1787                        cprm->file->f_pos, offset);
1788         }
1789
1790 end_coredump:
1791         set_fs(fs);
1792
1793 cleanup:
1794         while (!list_empty(&thread_list)) {
1795                 struct list_head *tmp = thread_list.next;
1796                 list_del(tmp);
1797                 kfree(list_entry(tmp, struct elf_thread_status, list));
1798         }
1799         kfree(phdr4note);
1800         kfree(elf);
1801         kfree(prstatus);
1802         kfree(psinfo);
1803         kfree(notes);
1804         kfree(fpu);
1805         kfree(shdr4extnum);
1806 #ifdef ELF_CORE_COPY_XFPREGS
1807         kfree(xfpu);
1808 #endif
1809         return has_dumped;
1810 #undef NUM_NOTES
1811 }
1812
1813 #endif          /* CONFIG_ELF_CORE */