fs/binfmt_elf_fdpic.c

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