1 /* 2 * linux/fs/binfmt_elf.c 3 * 4 * These are the functions used to load ELF format executables as used 5 * on SVr4 machines. Information on the format may be found in the book 6 * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support 7 * Tools". 8 * 9 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com). 10 */ 11 12 #include <linux/module.h> 13 #include <linux/kernel.h> 14 #include <linux/fs.h> 15 #include <linux/mm.h> 16 #include <linux/mman.h> 17 #include <linux/errno.h> 18 #include <linux/signal.h> 19 #include <linux/binfmts.h> 20 #include <linux/string.h> 21 #include <linux/file.h> 22 #include <linux/slab.h> 23 #include <linux/personality.h> 24 #include <linux/elfcore.h> 25 #include <linux/init.h> 26 #include <linux/highuid.h> 27 #include <linux/compiler.h> 28 #include <linux/highmem.h> 29 #include <linux/pagemap.h> 30 #include <linux/vmalloc.h> 31 #include <linux/security.h> 32 #include <linux/random.h> 33 #include <linux/elf.h> 34 #include <linux/utsname.h> 35 #include <linux/coredump.h> 36 #include <linux/sched.h> 37 #include <asm/uaccess.h> 38 #include <asm/param.h> 39 #include <asm/page.h> 40 41 #ifndef user_long_t 42 #define user_long_t long 43 #endif 44 #ifndef user_siginfo_t 45 #define user_siginfo_t siginfo_t 46 #endif 47 48 static int load_elf_binary(struct linux_binprm *bprm); 49 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *, 50 int, int, unsigned long); 51 52 #ifdef CONFIG_USELIB 53 static int load_elf_library(struct file *); 54 #else 55 #define load_elf_library NULL 56 #endif 57 58 /* 59 * If we don't support core dumping, then supply a NULL so we 60 * don't even try. 61 */ 62 #ifdef CONFIG_ELF_CORE 63 static int elf_core_dump(struct coredump_params *cprm); 64 #else 65 #define elf_core_dump NULL 66 #endif 67 68 #if ELF_EXEC_PAGESIZE > PAGE_SIZE 69 #define ELF_MIN_ALIGN ELF_EXEC_PAGESIZE 70 #else 71 #define ELF_MIN_ALIGN PAGE_SIZE 72 #endif 73 74 #ifndef ELF_CORE_EFLAGS 75 #define ELF_CORE_EFLAGS 0 76 #endif 77 78 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1)) 79 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1)) 80 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1)) 81 82 static struct linux_binfmt elf_format = { 83 .module = THIS_MODULE, 84 .load_binary = load_elf_binary, 85 .load_shlib = load_elf_library, 86 .core_dump = elf_core_dump, 87 .min_coredump = ELF_EXEC_PAGESIZE, 88 }; 89 90 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE) 91 92 static int set_brk(unsigned long start, unsigned long end) 93 { 94 start = ELF_PAGEALIGN(start); 95 end = ELF_PAGEALIGN(end); 96 if (end > start) { 97 unsigned long addr; 98 addr = vm_brk(start, end - start); 99 if (BAD_ADDR(addr)) 100 return addr; 101 } 102 current->mm->start_brk = current->mm->brk = end; 103 return 0; 104 } 105 106 /* We need to explicitly zero any fractional pages 107 after the data section (i.e. bss). This would 108 contain the junk from the file that should not 109 be in memory 110 */ 111 static int padzero(unsigned long elf_bss) 112 { 113 unsigned long nbyte; 114 115 nbyte = ELF_PAGEOFFSET(elf_bss); 116 if (nbyte) { 117 nbyte = ELF_MIN_ALIGN - nbyte; 118 if (clear_user((void __user *) elf_bss, nbyte)) 119 return -EFAULT; 120 } 121 return 0; 122 } 123 124 /* Let's use some macros to make this stack manipulation a little clearer */ 125 #ifdef CONFIG_STACK_GROWSUP 126 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items)) 127 #define STACK_ROUND(sp, items) \ 128 ((15 + (unsigned long) ((sp) + (items))) &~ 15UL) 129 #define STACK_ALLOC(sp, len) ({ \ 130 elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \ 131 old_sp; }) 132 #else 133 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items)) 134 #define STACK_ROUND(sp, items) \ 135 (((unsigned long) (sp - items)) &~ 15UL) 136 #define STACK_ALLOC(sp, len) ({ sp -= len ; sp; }) 137 #endif 138 139 #ifndef ELF_BASE_PLATFORM 140 /* 141 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture. 142 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value 143 * will be copied to the user stack in the same manner as AT_PLATFORM. 144 */ 145 #define ELF_BASE_PLATFORM NULL 146 #endif 147 148 static int 149 create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec, 150 unsigned long load_addr, unsigned long interp_load_addr) 151 { 152 unsigned long p = bprm->p; 153 int argc = bprm->argc; 154 int envc = bprm->envc; 155 elf_addr_t __user *argv; 156 elf_addr_t __user *envp; 157 elf_addr_t __user *sp; 158 elf_addr_t __user *u_platform; 159 elf_addr_t __user *u_base_platform; 160 elf_addr_t __user *u_rand_bytes; 161 const char *k_platform = ELF_PLATFORM; 162 const char *k_base_platform = ELF_BASE_PLATFORM; 163 unsigned char k_rand_bytes[16]; 164 int items; 165 elf_addr_t *elf_info; 166 int ei_index = 0; 167 const struct cred *cred = current_cred(); 168 struct vm_area_struct *vma; 169 170 /* 171 * In some cases (e.g. Hyper-Threading), we want to avoid L1 172 * evictions by the processes running on the same package. One 173 * thing we can do is to shuffle the initial stack for them. 174 */ 175 176 p = arch_align_stack(p); 177 178 /* 179 * If this architecture has a platform capability string, copy it 180 * to userspace. In some cases (Sparc), this info is impossible 181 * for userspace to get any other way, in others (i386) it is 182 * merely difficult. 183 */ 184 u_platform = NULL; 185 if (k_platform) { 186 size_t len = strlen(k_platform) + 1; 187 188 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len); 189 if (__copy_to_user(u_platform, k_platform, len)) 190 return -EFAULT; 191 } 192 193 /* 194 * If this architecture has a "base" platform capability 195 * string, copy it to userspace. 196 */ 197 u_base_platform = NULL; 198 if (k_base_platform) { 199 size_t len = strlen(k_base_platform) + 1; 200 201 u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len); 202 if (__copy_to_user(u_base_platform, k_base_platform, len)) 203 return -EFAULT; 204 } 205 206 /* 207 * Generate 16 random bytes for userspace PRNG seeding. 208 */ 209 get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes)); 210 u_rand_bytes = (elf_addr_t __user *) 211 STACK_ALLOC(p, sizeof(k_rand_bytes)); 212 if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes))) 213 return -EFAULT; 214 215 /* Create the ELF interpreter info */ 216 elf_info = (elf_addr_t *)current->mm->saved_auxv; 217 /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */ 218 #define NEW_AUX_ENT(id, val) \ 219 do { \ 220 elf_info[ei_index++] = id; \ 221 elf_info[ei_index++] = val; \ 222 } while (0) 223 224 #ifdef ARCH_DLINFO 225 /* 226 * ARCH_DLINFO must come first so PPC can do its special alignment of 227 * AUXV. 228 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in 229 * ARCH_DLINFO changes 230 */ 231 ARCH_DLINFO; 232 #endif 233 NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP); 234 NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE); 235 NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC); 236 NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff); 237 NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr)); 238 NEW_AUX_ENT(AT_PHNUM, exec->e_phnum); 239 NEW_AUX_ENT(AT_BASE, interp_load_addr); 240 NEW_AUX_ENT(AT_FLAGS, 0); 241 NEW_AUX_ENT(AT_ENTRY, exec->e_entry); 242 NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid)); 243 NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid)); 244 NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid)); 245 NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid)); 246 NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm)); 247 NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes); 248 #ifdef ELF_HWCAP2 249 NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2); 250 #endif 251 NEW_AUX_ENT(AT_EXECFN, bprm->exec); 252 if (k_platform) { 253 NEW_AUX_ENT(AT_PLATFORM, 254 (elf_addr_t)(unsigned long)u_platform); 255 } 256 if (k_base_platform) { 257 NEW_AUX_ENT(AT_BASE_PLATFORM, 258 (elf_addr_t)(unsigned long)u_base_platform); 259 } 260 if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) { 261 NEW_AUX_ENT(AT_EXECFD, bprm->interp_data); 262 } 263 #undef NEW_AUX_ENT 264 /* AT_NULL is zero; clear the rest too */ 265 memset(&elf_info[ei_index], 0, 266 sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]); 267 268 /* And advance past the AT_NULL entry. */ 269 ei_index += 2; 270 271 sp = STACK_ADD(p, ei_index); 272 273 items = (argc + 1) + (envc + 1) + 1; 274 bprm->p = STACK_ROUND(sp, items); 275 276 /* Point sp at the lowest address on the stack */ 277 #ifdef CONFIG_STACK_GROWSUP 278 sp = (elf_addr_t __user *)bprm->p - items - ei_index; 279 bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */ 280 #else 281 sp = (elf_addr_t __user *)bprm->p; 282 #endif 283 284 285 /* 286 * Grow the stack manually; some architectures have a limit on how 287 * far ahead a user-space access may be in order to grow the stack. 288 */ 289 vma = find_extend_vma(current->mm, bprm->p); 290 if (!vma) 291 return -EFAULT; 292 293 /* Now, let's put argc (and argv, envp if appropriate) on the stack */ 294 if (__put_user(argc, sp++)) 295 return -EFAULT; 296 argv = sp; 297 envp = argv + argc + 1; 298 299 /* Populate argv and envp */ 300 p = current->mm->arg_end = current->mm->arg_start; 301 while (argc-- > 0) { 302 size_t len; 303 if (__put_user((elf_addr_t)p, argv++)) 304 return -EFAULT; 305 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN); 306 if (!len || len > MAX_ARG_STRLEN) 307 return -EINVAL; 308 p += len; 309 } 310 if (__put_user(0, argv)) 311 return -EFAULT; 312 current->mm->arg_end = current->mm->env_start = p; 313 while (envc-- > 0) { 314 size_t len; 315 if (__put_user((elf_addr_t)p, envp++)) 316 return -EFAULT; 317 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN); 318 if (!len || len > MAX_ARG_STRLEN) 319 return -EINVAL; 320 p += len; 321 } 322 if (__put_user(0, envp)) 323 return -EFAULT; 324 current->mm->env_end = p; 325 326 /* Put the elf_info on the stack in the right place. */ 327 sp = (elf_addr_t __user *)envp + 1; 328 if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t))) 329 return -EFAULT; 330 return 0; 331 } 332 333 #ifndef elf_map 334 335 static unsigned long elf_map(struct file *filep, unsigned long addr, 336 struct elf_phdr *eppnt, int prot, int type, 337 unsigned long total_size) 338 { 339 unsigned long map_addr; 340 unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr); 341 unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr); 342 addr = ELF_PAGESTART(addr); 343 size = ELF_PAGEALIGN(size); 344 345 /* mmap() will return -EINVAL if given a zero size, but a 346 * segment with zero filesize is perfectly valid */ 347 if (!size) 348 return addr; 349 350 /* 351 * total_size is the size of the ELF (interpreter) image. 352 * The _first_ mmap needs to know the full size, otherwise 353 * randomization might put this image into an overlapping 354 * position with the ELF binary image. (since size < total_size) 355 * So we first map the 'big' image - and unmap the remainder at 356 * the end. (which unmap is needed for ELF images with holes.) 357 */ 358 if (total_size) { 359 total_size = ELF_PAGEALIGN(total_size); 360 map_addr = vm_mmap(filep, addr, total_size, prot, type, off); 361 if (!BAD_ADDR(map_addr)) 362 vm_munmap(map_addr+size, total_size-size); 363 } else 364 map_addr = vm_mmap(filep, addr, size, prot, type, off); 365 366 return(map_addr); 367 } 368 369 #endif /* !elf_map */ 370 371 static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr) 372 { 373 int i, first_idx = -1, last_idx = -1; 374 375 for (i = 0; i < nr; i++) { 376 if (cmds[i].p_type == PT_LOAD) { 377 last_idx = i; 378 if (first_idx == -1) 379 first_idx = i; 380 } 381 } 382 if (first_idx == -1) 383 return 0; 384 385 return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz - 386 ELF_PAGESTART(cmds[first_idx].p_vaddr); 387 } 388 389 390 /* This is much more generalized than the library routine read function, 391 so we keep this separate. Technically the library read function 392 is only provided so that we can read a.out libraries that have 393 an ELF header */ 394 395 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, 396 struct file *interpreter, unsigned long *interp_map_addr, 397 unsigned long no_base) 398 { 399 struct elf_phdr *elf_phdata; 400 struct elf_phdr *eppnt; 401 unsigned long load_addr = 0; 402 int load_addr_set = 0; 403 unsigned long last_bss = 0, elf_bss = 0; 404 unsigned long error = ~0UL; 405 unsigned long total_size; 406 int retval, i, size; 407 408 /* First of all, some simple consistency checks */ 409 if (interp_elf_ex->e_type != ET_EXEC && 410 interp_elf_ex->e_type != ET_DYN) 411 goto out; 412 if (!elf_check_arch(interp_elf_ex)) 413 goto out; 414 if (!interpreter->f_op->mmap) 415 goto out; 416 417 /* 418 * If the size of this structure has changed, then punt, since 419 * we will be doing the wrong thing. 420 */ 421 if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr)) 422 goto out; 423 if (interp_elf_ex->e_phnum < 1 || 424 interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr)) 425 goto out; 426 427 /* Now read in all of the header information */ 428 size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum; 429 if (size > ELF_MIN_ALIGN) 430 goto out; 431 elf_phdata = kmalloc(size, GFP_KERNEL); 432 if (!elf_phdata) 433 goto out; 434 435 retval = kernel_read(interpreter, interp_elf_ex->e_phoff, 436 (char *)elf_phdata, size); 437 error = -EIO; 438 if (retval != size) { 439 if (retval < 0) 440 error = retval; 441 goto out_close; 442 } 443 444 total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum); 445 if (!total_size) { 446 error = -EINVAL; 447 goto out_close; 448 } 449 450 eppnt = elf_phdata; 451 for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) { 452 if (eppnt->p_type == PT_LOAD) { 453 int elf_type = MAP_PRIVATE | MAP_DENYWRITE; 454 int elf_prot = 0; 455 unsigned long vaddr = 0; 456 unsigned long k, map_addr; 457 458 if (eppnt->p_flags & PF_R) 459 elf_prot = PROT_READ; 460 if (eppnt->p_flags & PF_W) 461 elf_prot |= PROT_WRITE; 462 if (eppnt->p_flags & PF_X) 463 elf_prot |= PROT_EXEC; 464 vaddr = eppnt->p_vaddr; 465 if (interp_elf_ex->e_type == ET_EXEC || load_addr_set) 466 elf_type |= MAP_FIXED; 467 else if (no_base && interp_elf_ex->e_type == ET_DYN) 468 load_addr = -vaddr; 469 470 map_addr = elf_map(interpreter, load_addr + vaddr, 471 eppnt, elf_prot, elf_type, total_size); 472 total_size = 0; 473 if (!*interp_map_addr) 474 *interp_map_addr = map_addr; 475 error = map_addr; 476 if (BAD_ADDR(map_addr)) 477 goto out_close; 478 479 if (!load_addr_set && 480 interp_elf_ex->e_type == ET_DYN) { 481 load_addr = map_addr - ELF_PAGESTART(vaddr); 482 load_addr_set = 1; 483 } 484 485 /* 486 * Check to see if the section's size will overflow the 487 * allowed task size. Note that p_filesz must always be 488 * <= p_memsize so it's only necessary to check p_memsz. 489 */ 490 k = load_addr + eppnt->p_vaddr; 491 if (BAD_ADDR(k) || 492 eppnt->p_filesz > eppnt->p_memsz || 493 eppnt->p_memsz > TASK_SIZE || 494 TASK_SIZE - eppnt->p_memsz < k) { 495 error = -ENOMEM; 496 goto out_close; 497 } 498 499 /* 500 * Find the end of the file mapping for this phdr, and 501 * keep track of the largest address we see for this. 502 */ 503 k = load_addr + eppnt->p_vaddr + eppnt->p_filesz; 504 if (k > elf_bss) 505 elf_bss = k; 506 507 /* 508 * Do the same thing for the memory mapping - between 509 * elf_bss and last_bss is the bss section. 510 */ 511 k = load_addr + eppnt->p_memsz + eppnt->p_vaddr; 512 if (k > last_bss) 513 last_bss = k; 514 } 515 } 516 517 if (last_bss > elf_bss) { 518 /* 519 * Now fill out the bss section. First pad the last page up 520 * to the page boundary, and then perform a mmap to make sure 521 * that there are zero-mapped pages up to and including the 522 * last bss page. 523 */ 524 if (padzero(elf_bss)) { 525 error = -EFAULT; 526 goto out_close; 527 } 528 529 /* What we have mapped so far */ 530 elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1); 531 532 /* Map the last of the bss segment */ 533 error = vm_brk(elf_bss, last_bss - elf_bss); 534 if (BAD_ADDR(error)) 535 goto out_close; 536 } 537 538 error = load_addr; 539 540 out_close: 541 kfree(elf_phdata); 542 out: 543 return error; 544 } 545 546 /* 547 * These are the functions used to load ELF style executables and shared 548 * libraries. There is no binary dependent code anywhere else. 549 */ 550 551 #ifndef STACK_RND_MASK 552 #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */ 553 #endif 554 555 static unsigned long randomize_stack_top(unsigned long stack_top) 556 { 557 unsigned int random_variable = 0; 558 559 if ((current->flags & PF_RANDOMIZE) && 560 !(current->personality & ADDR_NO_RANDOMIZE)) { 561 random_variable = get_random_int() & STACK_RND_MASK; 562 random_variable <<= PAGE_SHIFT; 563 } 564 #ifdef CONFIG_STACK_GROWSUP 565 return PAGE_ALIGN(stack_top) + random_variable; 566 #else 567 return PAGE_ALIGN(stack_top) - random_variable; 568 #endif 569 } 570 571 static int load_elf_binary(struct linux_binprm *bprm) 572 { 573 struct file *interpreter = NULL; /* to shut gcc up */ 574 unsigned long load_addr = 0, load_bias = 0; 575 int load_addr_set = 0; 576 char * elf_interpreter = NULL; 577 unsigned long error; 578 struct elf_phdr *elf_ppnt, *elf_phdata; 579 unsigned long elf_bss, elf_brk; 580 int retval, i; 581 unsigned int size; 582 unsigned long elf_entry; 583 unsigned long interp_load_addr = 0; 584 unsigned long start_code, end_code, start_data, end_data; 585 unsigned long reloc_func_desc __maybe_unused = 0; 586 int executable_stack = EXSTACK_DEFAULT; 587 struct pt_regs *regs = current_pt_regs(); 588 struct { 589 struct elfhdr elf_ex; 590 struct elfhdr interp_elf_ex; 591 } *loc; 592 593 loc = kmalloc(sizeof(*loc), GFP_KERNEL); 594 if (!loc) { 595 retval = -ENOMEM; 596 goto out_ret; 597 } 598 599 /* Get the exec-header */ 600 loc->elf_ex = *((struct elfhdr *)bprm->buf); 601 602 retval = -ENOEXEC; 603 /* First of all, some simple consistency checks */ 604 if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0) 605 goto out; 606 607 if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN) 608 goto out; 609 if (!elf_check_arch(&loc->elf_ex)) 610 goto out; 611 if (!bprm->file->f_op->mmap) 612 goto out; 613 614 /* Now read in all of the header information */ 615 if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr)) 616 goto out; 617 if (loc->elf_ex.e_phnum < 1 || 618 loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr)) 619 goto out; 620 size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr); 621 retval = -ENOMEM; 622 elf_phdata = kmalloc(size, GFP_KERNEL); 623 if (!elf_phdata) 624 goto out; 625 626 retval = kernel_read(bprm->file, loc->elf_ex.e_phoff, 627 (char *)elf_phdata, size); 628 if (retval != size) { 629 if (retval >= 0) 630 retval = -EIO; 631 goto out_free_ph; 632 } 633 634 elf_ppnt = elf_phdata; 635 elf_bss = 0; 636 elf_brk = 0; 637 638 start_code = ~0UL; 639 end_code = 0; 640 start_data = 0; 641 end_data = 0; 642 643 for (i = 0; i < loc->elf_ex.e_phnum; i++) { 644 if (elf_ppnt->p_type == PT_INTERP) { 645 /* This is the program interpreter used for 646 * shared libraries - for now assume that this 647 * is an a.out format binary 648 */ 649 retval = -ENOEXEC; 650 if (elf_ppnt->p_filesz > PATH_MAX || 651 elf_ppnt->p_filesz < 2) 652 goto out_free_ph; 653 654 retval = -ENOMEM; 655 elf_interpreter = kmalloc(elf_ppnt->p_filesz, 656 GFP_KERNEL); 657 if (!elf_interpreter) 658 goto out_free_ph; 659 660 retval = kernel_read(bprm->file, elf_ppnt->p_offset, 661 elf_interpreter, 662 elf_ppnt->p_filesz); 663 if (retval != elf_ppnt->p_filesz) { 664 if (retval >= 0) 665 retval = -EIO; 666 goto out_free_interp; 667 } 668 /* make sure path is NULL terminated */ 669 retval = -ENOEXEC; 670 if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0') 671 goto out_free_interp; 672 673 interpreter = open_exec(elf_interpreter); 674 retval = PTR_ERR(interpreter); 675 if (IS_ERR(interpreter)) 676 goto out_free_interp; 677 678 /* 679 * If the binary is not readable then enforce 680 * mm->dumpable = 0 regardless of the interpreter's 681 * permissions. 682 */ 683 would_dump(bprm, interpreter); 684 685 retval = kernel_read(interpreter, 0, bprm->buf, 686 BINPRM_BUF_SIZE); 687 if (retval != BINPRM_BUF_SIZE) { 688 if (retval >= 0) 689 retval = -EIO; 690 goto out_free_dentry; 691 } 692 693 /* Get the exec headers */ 694 loc->interp_elf_ex = *((struct elfhdr *)bprm->buf); 695 break; 696 } 697 elf_ppnt++; 698 } 699 700 elf_ppnt = elf_phdata; 701 for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++) 702 if (elf_ppnt->p_type == PT_GNU_STACK) { 703 if (elf_ppnt->p_flags & PF_X) 704 executable_stack = EXSTACK_ENABLE_X; 705 else 706 executable_stack = EXSTACK_DISABLE_X; 707 break; 708 } 709 710 /* Some simple consistency checks for the interpreter */ 711 if (elf_interpreter) { 712 retval = -ELIBBAD; 713 /* Not an ELF interpreter */ 714 if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0) 715 goto out_free_dentry; 716 /* Verify the interpreter has a valid arch */ 717 if (!elf_check_arch(&loc->interp_elf_ex)) 718 goto out_free_dentry; 719 } 720 721 /* Flush all traces of the currently running executable */ 722 retval = flush_old_exec(bprm); 723 if (retval) 724 goto out_free_dentry; 725 726 /* Do this immediately, since STACK_TOP as used in setup_arg_pages 727 may depend on the personality. */ 728 SET_PERSONALITY(loc->elf_ex); 729 if (elf_read_implies_exec(loc->elf_ex, executable_stack)) 730 current->personality |= READ_IMPLIES_EXEC; 731 732 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 733 current->flags |= PF_RANDOMIZE; 734 735 setup_new_exec(bprm); 736 737 /* Do this so that we can load the interpreter, if need be. We will 738 change some of these later */ 739 retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP), 740 executable_stack); 741 if (retval < 0) { 742 send_sig(SIGKILL, current, 0); 743 goto out_free_dentry; 744 } 745 746 current->mm->start_stack = bprm->p; 747 748 /* Now we do a little grungy work by mmapping the ELF image into 749 the correct location in memory. */ 750 for(i = 0, elf_ppnt = elf_phdata; 751 i < loc->elf_ex.e_phnum; i++, elf_ppnt++) { 752 int elf_prot = 0, elf_flags; 753 unsigned long k, vaddr; 754 755 if (elf_ppnt->p_type != PT_LOAD) 756 continue; 757 758 if (unlikely (elf_brk > elf_bss)) { 759 unsigned long nbyte; 760 761 /* There was a PT_LOAD segment with p_memsz > p_filesz 762 before this one. Map anonymous pages, if needed, 763 and clear the area. */ 764 retval = set_brk(elf_bss + load_bias, 765 elf_brk + load_bias); 766 if (retval) { 767 send_sig(SIGKILL, current, 0); 768 goto out_free_dentry; 769 } 770 nbyte = ELF_PAGEOFFSET(elf_bss); 771 if (nbyte) { 772 nbyte = ELF_MIN_ALIGN - nbyte; 773 if (nbyte > elf_brk - elf_bss) 774 nbyte = elf_brk - elf_bss; 775 if (clear_user((void __user *)elf_bss + 776 load_bias, nbyte)) { 777 /* 778 * This bss-zeroing can fail if the ELF 779 * file specifies odd protections. So 780 * we don't check the return value 781 */ 782 } 783 } 784 } 785 786 if (elf_ppnt->p_flags & PF_R) 787 elf_prot |= PROT_READ; 788 if (elf_ppnt->p_flags & PF_W) 789 elf_prot |= PROT_WRITE; 790 if (elf_ppnt->p_flags & PF_X) 791 elf_prot |= PROT_EXEC; 792 793 elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE; 794 795 vaddr = elf_ppnt->p_vaddr; 796 if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) { 797 elf_flags |= MAP_FIXED; 798 } else if (loc->elf_ex.e_type == ET_DYN) { 799 /* Try and get dynamic programs out of the way of the 800 * default mmap base, as well as whatever program they 801 * might try to exec. This is because the brk will 802 * follow the loader, and is not movable. */ 803 #ifdef CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE 804 /* Memory randomization might have been switched off 805 * in runtime via sysctl or explicit setting of 806 * personality flags. 807 * If that is the case, retain the original non-zero 808 * load_bias value in order to establish proper 809 * non-randomized mappings. 810 */ 811 if (current->flags & PF_RANDOMIZE) 812 load_bias = 0; 813 else 814 load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr); 815 #else 816 load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr); 817 #endif 818 } 819 820 error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt, 821 elf_prot, elf_flags, 0); 822 if (BAD_ADDR(error)) { 823 send_sig(SIGKILL, current, 0); 824 retval = IS_ERR((void *)error) ? 825 PTR_ERR((void*)error) : -EINVAL; 826 goto out_free_dentry; 827 } 828 829 if (!load_addr_set) { 830 load_addr_set = 1; 831 load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset); 832 if (loc->elf_ex.e_type == ET_DYN) { 833 load_bias += error - 834 ELF_PAGESTART(load_bias + vaddr); 835 load_addr += load_bias; 836 reloc_func_desc = load_bias; 837 } 838 } 839 k = elf_ppnt->p_vaddr; 840 if (k < start_code) 841 start_code = k; 842 if (start_data < k) 843 start_data = k; 844 845 /* 846 * Check to see if the section's size will overflow the 847 * allowed task size. Note that p_filesz must always be 848 * <= p_memsz so it is only necessary to check p_memsz. 849 */ 850 if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz || 851 elf_ppnt->p_memsz > TASK_SIZE || 852 TASK_SIZE - elf_ppnt->p_memsz < k) { 853 /* set_brk can never work. Avoid overflows. */ 854 send_sig(SIGKILL, current, 0); 855 retval = -EINVAL; 856 goto out_free_dentry; 857 } 858 859 k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz; 860 861 if (k > elf_bss) 862 elf_bss = k; 863 if ((elf_ppnt->p_flags & PF_X) && end_code < k) 864 end_code = k; 865 if (end_data < k) 866 end_data = k; 867 k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz; 868 if (k > elf_brk) 869 elf_brk = k; 870 } 871 872 loc->elf_ex.e_entry += load_bias; 873 elf_bss += load_bias; 874 elf_brk += load_bias; 875 start_code += load_bias; 876 end_code += load_bias; 877 start_data += load_bias; 878 end_data += load_bias; 879 880 /* Calling set_brk effectively mmaps the pages that we need 881 * for the bss and break sections. We must do this before 882 * mapping in the interpreter, to make sure it doesn't wind 883 * up getting placed where the bss needs to go. 884 */ 885 retval = set_brk(elf_bss, elf_brk); 886 if (retval) { 887 send_sig(SIGKILL, current, 0); 888 goto out_free_dentry; 889 } 890 if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) { 891 send_sig(SIGSEGV, current, 0); 892 retval = -EFAULT; /* Nobody gets to see this, but.. */ 893 goto out_free_dentry; 894 } 895 896 if (elf_interpreter) { 897 unsigned long interp_map_addr = 0; 898 899 elf_entry = load_elf_interp(&loc->interp_elf_ex, 900 interpreter, 901 &interp_map_addr, 902 load_bias); 903 if (!IS_ERR((void *)elf_entry)) { 904 /* 905 * load_elf_interp() returns relocation 906 * adjustment 907 */ 908 interp_load_addr = elf_entry; 909 elf_entry += loc->interp_elf_ex.e_entry; 910 } 911 if (BAD_ADDR(elf_entry)) { 912 force_sig(SIGSEGV, current); 913 retval = IS_ERR((void *)elf_entry) ? 914 (int)elf_entry : -EINVAL; 915 goto out_free_dentry; 916 } 917 reloc_func_desc = interp_load_addr; 918 919 allow_write_access(interpreter); 920 fput(interpreter); 921 kfree(elf_interpreter); 922 } else { 923 elf_entry = loc->elf_ex.e_entry; 924 if (BAD_ADDR(elf_entry)) { 925 force_sig(SIGSEGV, current); 926 retval = -EINVAL; 927 goto out_free_dentry; 928 } 929 } 930 931 kfree(elf_phdata); 932 933 set_binfmt(&elf_format); 934 935 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES 936 retval = arch_setup_additional_pages(bprm, !!elf_interpreter); 937 if (retval < 0) { 938 send_sig(SIGKILL, current, 0); 939 goto out; 940 } 941 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */ 942 943 install_exec_creds(bprm); 944 retval = create_elf_tables(bprm, &loc->elf_ex, 945 load_addr, interp_load_addr); 946 if (retval < 0) { 947 send_sig(SIGKILL, current, 0); 948 goto out; 949 } 950 /* N.B. passed_fileno might not be initialized? */ 951 current->mm->end_code = end_code; 952 current->mm->start_code = start_code; 953 current->mm->start_data = start_data; 954 current->mm->end_data = end_data; 955 current->mm->start_stack = bprm->p; 956 957 #ifdef arch_randomize_brk 958 if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) { 959 current->mm->brk = current->mm->start_brk = 960 arch_randomize_brk(current->mm); 961 #ifdef CONFIG_COMPAT_BRK 962 current->brk_randomized = 1; 963 #endif 964 } 965 #endif 966 967 if (current->personality & MMAP_PAGE_ZERO) { 968 /* Why this, you ask??? Well SVr4 maps page 0 as read-only, 969 and some applications "depend" upon this behavior. 970 Since we do not have the power to recompile these, we 971 emulate the SVr4 behavior. Sigh. */ 972 error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC, 973 MAP_FIXED | MAP_PRIVATE, 0); 974 } 975 976 #ifdef ELF_PLAT_INIT 977 /* 978 * The ABI may specify that certain registers be set up in special 979 * ways (on i386 %edx is the address of a DT_FINI function, for 980 * example. In addition, it may also specify (eg, PowerPC64 ELF) 981 * that the e_entry field is the address of the function descriptor 982 * for the startup routine, rather than the address of the startup 983 * routine itself. This macro performs whatever initialization to 984 * the regs structure is required as well as any relocations to the 985 * function descriptor entries when executing dynamically links apps. 986 */ 987 ELF_PLAT_INIT(regs, reloc_func_desc); 988 #endif 989 990 start_thread(regs, elf_entry, bprm->p); 991 retval = 0; 992 out: 993 kfree(loc); 994 out_ret: 995 return retval; 996 997 /* error cleanup */ 998 out_free_dentry: 999 allow_write_access(interpreter); 1000 if (interpreter) 1001 fput(interpreter); 1002 out_free_interp: 1003 kfree(elf_interpreter); 1004 out_free_ph: 1005 kfree(elf_phdata); 1006 goto out; 1007 } 1008 1009 #ifdef CONFIG_USELIB 1010 /* This is really simpleminded and specialized - we are loading an 1011 a.out library that is given an ELF header. */ 1012 static int load_elf_library(struct file *file) 1013 { 1014 struct elf_phdr *elf_phdata; 1015 struct elf_phdr *eppnt; 1016 unsigned long elf_bss, bss, len; 1017 int retval, error, i, j; 1018 struct elfhdr elf_ex; 1019 1020 error = -ENOEXEC; 1021 retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex)); 1022 if (retval != sizeof(elf_ex)) 1023 goto out; 1024 1025 if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0) 1026 goto out; 1027 1028 /* First of all, some simple consistency checks */ 1029 if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 || 1030 !elf_check_arch(&elf_ex) || !file->f_op->mmap) 1031 goto out; 1032 1033 /* Now read in all of the header information */ 1034 1035 j = sizeof(struct elf_phdr) * elf_ex.e_phnum; 1036 /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */ 1037 1038 error = -ENOMEM; 1039 elf_phdata = kmalloc(j, GFP_KERNEL); 1040 if (!elf_phdata) 1041 goto out; 1042 1043 eppnt = elf_phdata; 1044 error = -ENOEXEC; 1045 retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j); 1046 if (retval != j) 1047 goto out_free_ph; 1048 1049 for (j = 0, i = 0; i<elf_ex.e_phnum; i++) 1050 if ((eppnt + i)->p_type == PT_LOAD) 1051 j++; 1052 if (j != 1) 1053 goto out_free_ph; 1054 1055 while (eppnt->p_type != PT_LOAD) 1056 eppnt++; 1057 1058 /* Now use mmap to map the library into memory. */ 1059 error = vm_mmap(file, 1060 ELF_PAGESTART(eppnt->p_vaddr), 1061 (eppnt->p_filesz + 1062 ELF_PAGEOFFSET(eppnt->p_vaddr)), 1063 PROT_READ | PROT_WRITE | PROT_EXEC, 1064 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, 1065 (eppnt->p_offset - 1066 ELF_PAGEOFFSET(eppnt->p_vaddr))); 1067 if (error != ELF_PAGESTART(eppnt->p_vaddr)) 1068 goto out_free_ph; 1069 1070 elf_bss = eppnt->p_vaddr + eppnt->p_filesz; 1071 if (padzero(elf_bss)) { 1072 error = -EFAULT; 1073 goto out_free_ph; 1074 } 1075 1076 len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr + 1077 ELF_MIN_ALIGN - 1); 1078 bss = eppnt->p_memsz + eppnt->p_vaddr; 1079 if (bss > len) 1080 vm_brk(len, bss - len); 1081 error = 0; 1082 1083 out_free_ph: 1084 kfree(elf_phdata); 1085 out: 1086 return error; 1087 } 1088 #endif /* #ifdef CONFIG_USELIB */ 1089 1090 #ifdef CONFIG_ELF_CORE 1091 /* 1092 * ELF core dumper 1093 * 1094 * Modelled on fs/exec.c:aout_core_dump() 1095 * Jeremy Fitzhardinge <jeremy@sw.oz.au> 1096 */ 1097 1098 /* 1099 * The purpose of always_dump_vma() is to make sure that special kernel mappings 1100 * that are useful for post-mortem analysis are included in every core dump. 1101 * In that way we ensure that the core dump is fully interpretable later 1102 * without matching up the same kernel and hardware config to see what PC values 1103 * meant. These special mappings include - vDSO, vsyscall, and other 1104 * architecture specific mappings 1105 */ 1106 static bool always_dump_vma(struct vm_area_struct *vma) 1107 { 1108 /* Any vsyscall mappings? */ 1109 if (vma == get_gate_vma(vma->vm_mm)) 1110 return true; 1111 /* 1112 * arch_vma_name() returns non-NULL for special architecture mappings, 1113 * such as vDSO sections. 1114 */ 1115 if (arch_vma_name(vma)) 1116 return true; 1117 1118 return false; 1119 } 1120 1121 /* 1122 * Decide what to dump of a segment, part, all or none. 1123 */ 1124 static unsigned long vma_dump_size(struct vm_area_struct *vma, 1125 unsigned long mm_flags) 1126 { 1127 #define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) 1128 1129 /* always dump the vdso and vsyscall sections */ 1130 if (always_dump_vma(vma)) 1131 goto whole; 1132 1133 if (vma->vm_flags & VM_DONTDUMP) 1134 return 0; 1135 1136 /* Hugetlb memory check */ 1137 if (vma->vm_flags & VM_HUGETLB) { 1138 if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) 1139 goto whole; 1140 if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) 1141 goto whole; 1142 return 0; 1143 } 1144 1145 /* Do not dump I/O mapped devices or special mappings */ 1146 if (vma->vm_flags & VM_IO) 1147 return 0; 1148 1149 /* By default, dump shared memory if mapped from an anonymous file. */ 1150 if (vma->vm_flags & VM_SHARED) { 1151 if (file_inode(vma->vm_file)->i_nlink == 0 ? 1152 FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) 1153 goto whole; 1154 return 0; 1155 } 1156 1157 /* Dump segments that have been written to. */ 1158 if (vma->anon_vma && FILTER(ANON_PRIVATE)) 1159 goto whole; 1160 if (vma->vm_file == NULL) 1161 return 0; 1162 1163 if (FILTER(MAPPED_PRIVATE)) 1164 goto whole; 1165 1166 /* 1167 * If this looks like the beginning of a DSO or executable mapping, 1168 * check for an ELF header. If we find one, dump the first page to 1169 * aid in determining what was mapped here. 1170 */ 1171 if (FILTER(ELF_HEADERS) && 1172 vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { 1173 u32 __user *header = (u32 __user *) vma->vm_start; 1174 u32 word; 1175 mm_segment_t fs = get_fs(); 1176 /* 1177 * Doing it this way gets the constant folded by GCC. 1178 */ 1179 union { 1180 u32 cmp; 1181 char elfmag[SELFMAG]; 1182 } magic; 1183 BUILD_BUG_ON(SELFMAG != sizeof word); 1184 magic.elfmag[EI_MAG0] = ELFMAG0; 1185 magic.elfmag[EI_MAG1] = ELFMAG1; 1186 magic.elfmag[EI_MAG2] = ELFMAG2; 1187 magic.elfmag[EI_MAG3] = ELFMAG3; 1188 /* 1189 * Switch to the user "segment" for get_user(), 1190 * then put back what elf_core_dump() had in place. 1191 */ 1192 set_fs(USER_DS); 1193 if (unlikely(get_user(word, header))) 1194 word = 0; 1195 set_fs(fs); 1196 if (word == magic.cmp) 1197 return PAGE_SIZE; 1198 } 1199 1200 #undef FILTER 1201 1202 return 0; 1203 1204 whole: 1205 return vma->vm_end - vma->vm_start; 1206 } 1207 1208 /* An ELF note in memory */ 1209 struct memelfnote 1210 { 1211 const char *name; 1212 int type; 1213 unsigned int datasz; 1214 void *data; 1215 }; 1216 1217 static int notesize(struct memelfnote *en) 1218 { 1219 int sz; 1220 1221 sz = sizeof(struct elf_note); 1222 sz += roundup(strlen(en->name) + 1, 4); 1223 sz += roundup(en->datasz, 4); 1224 1225 return sz; 1226 } 1227 1228 static int writenote(struct memelfnote *men, struct coredump_params *cprm) 1229 { 1230 struct elf_note en; 1231 en.n_namesz = strlen(men->name) + 1; 1232 en.n_descsz = men->datasz; 1233 en.n_type = men->type; 1234 1235 return dump_emit(cprm, &en, sizeof(en)) && 1236 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) && 1237 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4); 1238 } 1239 1240 static void fill_elf_header(struct elfhdr *elf, int segs, 1241 u16 machine, u32 flags) 1242 { 1243 memset(elf, 0, sizeof(*elf)); 1244 1245 memcpy(elf->e_ident, ELFMAG, SELFMAG); 1246 elf->e_ident[EI_CLASS] = ELF_CLASS; 1247 elf->e_ident[EI_DATA] = ELF_DATA; 1248 elf->e_ident[EI_VERSION] = EV_CURRENT; 1249 elf->e_ident[EI_OSABI] = ELF_OSABI; 1250 1251 elf->e_type = ET_CORE; 1252 elf->e_machine = machine; 1253 elf->e_version = EV_CURRENT; 1254 elf->e_phoff = sizeof(struct elfhdr); 1255 elf->e_flags = flags; 1256 elf->e_ehsize = sizeof(struct elfhdr); 1257 elf->e_phentsize = sizeof(struct elf_phdr); 1258 elf->e_phnum = segs; 1259 1260 return; 1261 } 1262 1263 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset) 1264 { 1265 phdr->p_type = PT_NOTE; 1266 phdr->p_offset = offset; 1267 phdr->p_vaddr = 0; 1268 phdr->p_paddr = 0; 1269 phdr->p_filesz = sz; 1270 phdr->p_memsz = 0; 1271 phdr->p_flags = 0; 1272 phdr->p_align = 0; 1273 return; 1274 } 1275 1276 static void fill_note(struct memelfnote *note, const char *name, int type, 1277 unsigned int sz, void *data) 1278 { 1279 note->name = name; 1280 note->type = type; 1281 note->datasz = sz; 1282 note->data = data; 1283 return; 1284 } 1285 1286 /* 1287 * fill up all the fields in prstatus from the given task struct, except 1288 * registers which need to be filled up separately. 1289 */ 1290 static void fill_prstatus(struct elf_prstatus *prstatus, 1291 struct task_struct *p, long signr) 1292 { 1293 prstatus->pr_info.si_signo = prstatus->pr_cursig = signr; 1294 prstatus->pr_sigpend = p->pending.signal.sig[0]; 1295 prstatus->pr_sighold = p->blocked.sig[0]; 1296 rcu_read_lock(); 1297 prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent)); 1298 rcu_read_unlock(); 1299 prstatus->pr_pid = task_pid_vnr(p); 1300 prstatus->pr_pgrp = task_pgrp_vnr(p); 1301 prstatus->pr_sid = task_session_vnr(p); 1302 if (thread_group_leader(p)) { 1303 struct task_cputime cputime; 1304 1305 /* 1306 * This is the record for the group leader. It shows the 1307 * group-wide total, not its individual thread total. 1308 */ 1309 thread_group_cputime(p, &cputime); 1310 cputime_to_timeval(cputime.utime, &prstatus->pr_utime); 1311 cputime_to_timeval(cputime.stime, &prstatus->pr_stime); 1312 } else { 1313 cputime_t utime, stime; 1314 1315 task_cputime(p, &utime, &stime); 1316 cputime_to_timeval(utime, &prstatus->pr_utime); 1317 cputime_to_timeval(stime, &prstatus->pr_stime); 1318 } 1319 cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime); 1320 cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime); 1321 } 1322 1323 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p, 1324 struct mm_struct *mm) 1325 { 1326 const struct cred *cred; 1327 unsigned int i, len; 1328 1329 /* first copy the parameters from user space */ 1330 memset(psinfo, 0, sizeof(struct elf_prpsinfo)); 1331 1332 len = mm->arg_end - mm->arg_start; 1333 if (len >= ELF_PRARGSZ) 1334 len = ELF_PRARGSZ-1; 1335 if (copy_from_user(&psinfo->pr_psargs, 1336 (const char __user *)mm->arg_start, len)) 1337 return -EFAULT; 1338 for(i = 0; i < len; i++) 1339 if (psinfo->pr_psargs[i] == 0) 1340 psinfo->pr_psargs[i] = ' '; 1341 psinfo->pr_psargs[len] = 0; 1342 1343 rcu_read_lock(); 1344 psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent)); 1345 rcu_read_unlock(); 1346 psinfo->pr_pid = task_pid_vnr(p); 1347 psinfo->pr_pgrp = task_pgrp_vnr(p); 1348 psinfo->pr_sid = task_session_vnr(p); 1349 1350 i = p->state ? ffz(~p->state) + 1 : 0; 1351 psinfo->pr_state = i; 1352 psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i]; 1353 psinfo->pr_zomb = psinfo->pr_sname == 'Z'; 1354 psinfo->pr_nice = task_nice(p); 1355 psinfo->pr_flag = p->flags; 1356 rcu_read_lock(); 1357 cred = __task_cred(p); 1358 SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); 1359 SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); 1360 rcu_read_unlock(); 1361 strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); 1362 1363 return 0; 1364 } 1365 1366 static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) 1367 { 1368 elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv; 1369 int i = 0; 1370 do 1371 i += 2; 1372 while (auxv[i - 2] != AT_NULL); 1373 fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv); 1374 } 1375 1376 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, 1377 const siginfo_t *siginfo) 1378 { 1379 mm_segment_t old_fs = get_fs(); 1380 set_fs(KERNEL_DS); 1381 copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo); 1382 set_fs(old_fs); 1383 fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); 1384 } 1385 1386 #define MAX_FILE_NOTE_SIZE (4*1024*1024) 1387 /* 1388 * Format of NT_FILE note: 1389 * 1390 * long count -- how many files are mapped 1391 * long page_size -- units for file_ofs 1392 * array of [COUNT] elements of 1393 * long start 1394 * long end 1395 * long file_ofs 1396 * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL... 1397 */ 1398 static int fill_files_note(struct memelfnote *note) 1399 { 1400 struct vm_area_struct *vma; 1401 unsigned count, size, names_ofs, remaining, n; 1402 user_long_t *data; 1403 user_long_t *start_end_ofs; 1404 char *name_base, *name_curpos; 1405 1406 /* *Estimated* file count and total data size needed */ 1407 count = current->mm->map_count; 1408 size = count * 64; 1409 1410 names_ofs = (2 + 3 * count) * sizeof(data[0]); 1411 alloc: 1412 if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */ 1413 return -EINVAL; 1414 size = round_up(size, PAGE_SIZE); 1415 data = vmalloc(size); 1416 if (!data) 1417 return -ENOMEM; 1418 1419 start_end_ofs = data + 2; 1420 name_base = name_curpos = ((char *)data) + names_ofs; 1421 remaining = size - names_ofs; 1422 count = 0; 1423 for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) { 1424 struct file *file; 1425 const char *filename; 1426 1427 file = vma->vm_file; 1428 if (!file) 1429 continue; 1430 filename = d_path(&file->f_path, name_curpos, remaining); 1431 if (IS_ERR(filename)) { 1432 if (PTR_ERR(filename) == -ENAMETOOLONG) { 1433 vfree(data); 1434 size = size * 5 / 4; 1435 goto alloc; 1436 } 1437 continue; 1438 } 1439 1440 /* d_path() fills at the end, move name down */ 1441 /* n = strlen(filename) + 1: */ 1442 n = (name_curpos + remaining) - filename; 1443 remaining = filename - name_curpos; 1444 memmove(name_curpos, filename, n); 1445 name_curpos += n; 1446 1447 *start_end_ofs++ = vma->vm_start; 1448 *start_end_ofs++ = vma->vm_end; 1449 *start_end_ofs++ = vma->vm_pgoff; 1450 count++; 1451 } 1452 1453 /* Now we know exact count of files, can store it */ 1454 data[0] = count; 1455 data[1] = PAGE_SIZE; 1456 /* 1457 * Count usually is less than current->mm->map_count, 1458 * we need to move filenames down. 1459 */ 1460 n = current->mm->map_count - count; 1461 if (n != 0) { 1462 unsigned shift_bytes = n * 3 * sizeof(data[0]); 1463 memmove(name_base - shift_bytes, name_base, 1464 name_curpos - name_base); 1465 name_curpos -= shift_bytes; 1466 } 1467 1468 size = name_curpos - (char *)data; 1469 fill_note(note, "CORE", NT_FILE, size, data); 1470 return 0; 1471 } 1472 1473 #ifdef CORE_DUMP_USE_REGSET 1474 #include <linux/regset.h> 1475 1476 struct elf_thread_core_info { 1477 struct elf_thread_core_info *next; 1478 struct task_struct *task; 1479 struct elf_prstatus prstatus; 1480 struct memelfnote notes[0]; 1481 }; 1482 1483 struct elf_note_info { 1484 struct elf_thread_core_info *thread; 1485 struct memelfnote psinfo; 1486 struct memelfnote signote; 1487 struct memelfnote auxv; 1488 struct memelfnote files; 1489 user_siginfo_t csigdata; 1490 size_t size; 1491 int thread_notes; 1492 }; 1493 1494 /* 1495 * When a regset has a writeback hook, we call it on each thread before 1496 * dumping user memory. On register window machines, this makes sure the 1497 * user memory backing the register data is up to date before we read it. 1498 */ 1499 static void do_thread_regset_writeback(struct task_struct *task, 1500 const struct user_regset *regset) 1501 { 1502 if (regset->writeback) 1503 regset->writeback(task, regset, 1); 1504 } 1505 1506 #ifndef PR_REG_SIZE 1507 #define PR_REG_SIZE(S) sizeof(S) 1508 #endif 1509 1510 #ifndef PRSTATUS_SIZE 1511 #define PRSTATUS_SIZE(S) sizeof(S) 1512 #endif 1513 1514 #ifndef PR_REG_PTR 1515 #define PR_REG_PTR(S) (&((S)->pr_reg)) 1516 #endif 1517 1518 #ifndef SET_PR_FPVALID 1519 #define SET_PR_FPVALID(S, V) ((S)->pr_fpvalid = (V)) 1520 #endif 1521 1522 static int fill_thread_core_info(struct elf_thread_core_info *t, 1523 const struct user_regset_view *view, 1524 long signr, size_t *total) 1525 { 1526 unsigned int i; 1527 1528 /* 1529 * NT_PRSTATUS is the one special case, because the regset data 1530 * goes into the pr_reg field inside the note contents, rather 1531 * than being the whole note contents. We fill the reset in here. 1532 * We assume that regset 0 is NT_PRSTATUS. 1533 */ 1534 fill_prstatus(&t->prstatus, t->task, signr); 1535 (void) view->regsets[0].get(t->task, &view->regsets[0], 1536 0, PR_REG_SIZE(t->prstatus.pr_reg), 1537 PR_REG_PTR(&t->prstatus), NULL); 1538 1539 fill_note(&t->notes[0], "CORE", NT_PRSTATUS, 1540 PRSTATUS_SIZE(t->prstatus), &t->prstatus); 1541 *total += notesize(&t->notes[0]); 1542 1543 do_thread_regset_writeback(t->task, &view->regsets[0]); 1544 1545 /* 1546 * Each other regset might generate a note too. For each regset 1547 * that has no core_note_type or is inactive, we leave t->notes[i] 1548 * all zero and we'll know to skip writing it later. 1549 */ 1550 for (i = 1; i < view->n; ++i) { 1551 const struct user_regset *regset = &view->regsets[i]; 1552 do_thread_regset_writeback(t->task, regset); 1553 if (regset->core_note_type && regset->get && 1554 (!regset->active || regset->active(t->task, regset))) { 1555 int ret; 1556 size_t size = regset->n * regset->size; 1557 void *data = kmalloc(size, GFP_KERNEL); 1558 if (unlikely(!data)) 1559 return 0; 1560 ret = regset->get(t->task, regset, 1561 0, size, data, NULL); 1562 if (unlikely(ret)) 1563 kfree(data); 1564 else { 1565 if (regset->core_note_type != NT_PRFPREG) 1566 fill_note(&t->notes[i], "LINUX", 1567 regset->core_note_type, 1568 size, data); 1569 else { 1570 SET_PR_FPVALID(&t->prstatus, 1); 1571 fill_note(&t->notes[i], "CORE", 1572 NT_PRFPREG, size, data); 1573 } 1574 *total += notesize(&t->notes[i]); 1575 } 1576 } 1577 } 1578 1579 return 1; 1580 } 1581 1582 static int fill_note_info(struct elfhdr *elf, int phdrs, 1583 struct elf_note_info *info, 1584 const siginfo_t *siginfo, struct pt_regs *regs) 1585 { 1586 struct task_struct *dump_task = current; 1587 const struct user_regset_view *view = task_user_regset_view(dump_task); 1588 struct elf_thread_core_info *t; 1589 struct elf_prpsinfo *psinfo; 1590 struct core_thread *ct; 1591 unsigned int i; 1592 1593 info->size = 0; 1594 info->thread = NULL; 1595 1596 psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL); 1597 if (psinfo == NULL) { 1598 info->psinfo.data = NULL; /* So we don't free this wrongly */ 1599 return 0; 1600 } 1601 1602 fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo); 1603 1604 /* 1605 * Figure out how many notes we're going to need for each thread. 1606 */ 1607 info->thread_notes = 0; 1608 for (i = 0; i < view->n; ++i) 1609 if (view->regsets[i].core_note_type != 0) 1610 ++info->thread_notes; 1611 1612 /* 1613 * Sanity check. We rely on regset 0 being in NT_PRSTATUS, 1614 * since it is our one special case. 1615 */ 1616 if (unlikely(info->thread_notes == 0) || 1617 unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) { 1618 WARN_ON(1); 1619 return 0; 1620 } 1621 1622 /* 1623 * Initialize the ELF file header. 1624 */ 1625 fill_elf_header(elf, phdrs, 1626 view->e_machine, view->e_flags); 1627 1628 /* 1629 * Allocate a structure for each thread. 1630 */ 1631 for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) { 1632 t = kzalloc(offsetof(struct elf_thread_core_info, 1633 notes[info->thread_notes]), 1634 GFP_KERNEL); 1635 if (unlikely(!t)) 1636 return 0; 1637 1638 t->task = ct->task; 1639 if (ct->task == dump_task || !info->thread) { 1640 t->next = info->thread; 1641 info->thread = t; 1642 } else { 1643 /* 1644 * Make sure to keep the original task at 1645 * the head of the list. 1646 */ 1647 t->next = info->thread->next; 1648 info->thread->next = t; 1649 } 1650 } 1651 1652 /* 1653 * Now fill in each thread's information. 1654 */ 1655 for (t = info->thread; t != NULL; t = t->next) 1656 if (!fill_thread_core_info(t, view, siginfo->si_signo, &info->size)) 1657 return 0; 1658 1659 /* 1660 * Fill in the two process-wide notes. 1661 */ 1662 fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm); 1663 info->size += notesize(&info->psinfo); 1664 1665 fill_siginfo_note(&info->signote, &info->csigdata, siginfo); 1666 info->size += notesize(&info->signote); 1667 1668 fill_auxv_note(&info->auxv, current->mm); 1669 info->size += notesize(&info->auxv); 1670 1671 if (fill_files_note(&info->files) == 0) 1672 info->size += notesize(&info->files); 1673 1674 return 1; 1675 } 1676 1677 static size_t get_note_info_size(struct elf_note_info *info) 1678 { 1679 return info->size; 1680 } 1681 1682 /* 1683 * Write all the notes for each thread. When writing the first thread, the 1684 * process-wide notes are interleaved after the first thread-specific note. 1685 */ 1686 static int write_note_info(struct elf_note_info *info, 1687 struct coredump_params *cprm) 1688 { 1689 bool first = 1; 1690 struct elf_thread_core_info *t = info->thread; 1691 1692 do { 1693 int i; 1694 1695 if (!writenote(&t->notes[0], cprm)) 1696 return 0; 1697 1698 if (first && !writenote(&info->psinfo, cprm)) 1699 return 0; 1700 if (first && !writenote(&info->signote, cprm)) 1701 return 0; 1702 if (first && !writenote(&info->auxv, cprm)) 1703 return 0; 1704 if (first && info->files.data && 1705 !writenote(&info->files, cprm)) 1706 return 0; 1707 1708 for (i = 1; i < info->thread_notes; ++i) 1709 if (t->notes[i].data && 1710 !writenote(&t->notes[i], cprm)) 1711 return 0; 1712 1713 first = 0; 1714 t = t->next; 1715 } while (t); 1716 1717 return 1; 1718 } 1719 1720 static void free_note_info(struct elf_note_info *info) 1721 { 1722 struct elf_thread_core_info *threads = info->thread; 1723 while (threads) { 1724 unsigned int i; 1725 struct elf_thread_core_info *t = threads; 1726 threads = t->next; 1727 WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus); 1728 for (i = 1; i < info->thread_notes; ++i) 1729 kfree(t->notes[i].data); 1730 kfree(t); 1731 } 1732 kfree(info->psinfo.data); 1733 vfree(info->files.data); 1734 } 1735 1736 #else 1737 1738 /* Here is the structure in which status of each thread is captured. */ 1739 struct elf_thread_status 1740 { 1741 struct list_head list; 1742 struct elf_prstatus prstatus; /* NT_PRSTATUS */ 1743 elf_fpregset_t fpu; /* NT_PRFPREG */ 1744 struct task_struct *thread; 1745 #ifdef ELF_CORE_COPY_XFPREGS 1746 elf_fpxregset_t xfpu; /* ELF_CORE_XFPREG_TYPE */ 1747 #endif 1748 struct memelfnote notes[3]; 1749 int num_notes; 1750 }; 1751 1752 /* 1753 * In order to add the specific thread information for the elf file format, 1754 * we need to keep a linked list of every threads pr_status and then create 1755 * a single section for them in the final core file. 1756 */ 1757 static int elf_dump_thread_status(long signr, struct elf_thread_status *t) 1758 { 1759 int sz = 0; 1760 struct task_struct *p = t->thread; 1761 t->num_notes = 0; 1762 1763 fill_prstatus(&t->prstatus, p, signr); 1764 elf_core_copy_task_regs(p, &t->prstatus.pr_reg); 1765 1766 fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus), 1767 &(t->prstatus)); 1768 t->num_notes++; 1769 sz += notesize(&t->notes[0]); 1770 1771 if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, 1772 &t->fpu))) { 1773 fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu), 1774 &(t->fpu)); 1775 t->num_notes++; 1776 sz += notesize(&t->notes[1]); 1777 } 1778 1779 #ifdef ELF_CORE_COPY_XFPREGS 1780 if (elf_core_copy_task_xfpregs(p, &t->xfpu)) { 1781 fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE, 1782 sizeof(t->xfpu), &t->xfpu); 1783 t->num_notes++; 1784 sz += notesize(&t->notes[2]); 1785 } 1786 #endif 1787 return sz; 1788 } 1789 1790 struct elf_note_info { 1791 struct memelfnote *notes; 1792 struct memelfnote *notes_files; 1793 struct elf_prstatus *prstatus; /* NT_PRSTATUS */ 1794 struct elf_prpsinfo *psinfo; /* NT_PRPSINFO */ 1795 struct list_head thread_list; 1796 elf_fpregset_t *fpu; 1797 #ifdef ELF_CORE_COPY_XFPREGS 1798 elf_fpxregset_t *xfpu; 1799 #endif 1800 user_siginfo_t csigdata; 1801 int thread_status_size; 1802 int numnote; 1803 }; 1804 1805 static int elf_note_info_init(struct elf_note_info *info) 1806 { 1807 memset(info, 0, sizeof(*info)); 1808 INIT_LIST_HEAD(&info->thread_list); 1809 1810 /* Allocate space for ELF notes */ 1811 info->notes = kmalloc(8 * sizeof(struct memelfnote), GFP_KERNEL); 1812 if (!info->notes) 1813 return 0; 1814 info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL); 1815 if (!info->psinfo) 1816 return 0; 1817 info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL); 1818 if (!info->prstatus) 1819 return 0; 1820 info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL); 1821 if (!info->fpu) 1822 return 0; 1823 #ifdef ELF_CORE_COPY_XFPREGS 1824 info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL); 1825 if (!info->xfpu) 1826 return 0; 1827 #endif 1828 return 1; 1829 } 1830 1831 static int fill_note_info(struct elfhdr *elf, int phdrs, 1832 struct elf_note_info *info, 1833 const siginfo_t *siginfo, struct pt_regs *regs) 1834 { 1835 struct list_head *t; 1836 struct core_thread *ct; 1837 struct elf_thread_status *ets; 1838 1839 if (!elf_note_info_init(info)) 1840 return 0; 1841 1842 for (ct = current->mm->core_state->dumper.next; 1843 ct; ct = ct->next) { 1844 ets = kzalloc(sizeof(*ets), GFP_KERNEL); 1845 if (!ets) 1846 return 0; 1847 1848 ets->thread = ct->task; 1849 list_add(&ets->list, &info->thread_list); 1850 } 1851 1852 list_for_each(t, &info->thread_list) { 1853 int sz; 1854 1855 ets = list_entry(t, struct elf_thread_status, list); 1856 sz = elf_dump_thread_status(siginfo->si_signo, ets); 1857 info->thread_status_size += sz; 1858 } 1859 /* now collect the dump for the current */ 1860 memset(info->prstatus, 0, sizeof(*info->prstatus)); 1861 fill_prstatus(info->prstatus, current, siginfo->si_signo); 1862 elf_core_copy_regs(&info->prstatus->pr_reg, regs); 1863 1864 /* Set up header */ 1865 fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS); 1866 1867 /* 1868 * Set up the notes in similar form to SVR4 core dumps made 1869 * with info from their /proc. 1870 */ 1871 1872 fill_note(info->notes + 0, "CORE", NT_PRSTATUS, 1873 sizeof(*info->prstatus), info->prstatus); 1874 fill_psinfo(info->psinfo, current->group_leader, current->mm); 1875 fill_note(info->notes + 1, "CORE", NT_PRPSINFO, 1876 sizeof(*info->psinfo), info->psinfo); 1877 1878 fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo); 1879 fill_auxv_note(info->notes + 3, current->mm); 1880 info->numnote = 4; 1881 1882 if (fill_files_note(info->notes + info->numnote) == 0) { 1883 info->notes_files = info->notes + info->numnote; 1884 info->numnote++; 1885 } 1886 1887 /* Try to dump the FPU. */ 1888 info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs, 1889 info->fpu); 1890 if (info->prstatus->pr_fpvalid) 1891 fill_note(info->notes + info->numnote++, 1892 "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu); 1893 #ifdef ELF_CORE_COPY_XFPREGS 1894 if (elf_core_copy_task_xfpregs(current, info->xfpu)) 1895 fill_note(info->notes + info->numnote++, 1896 "LINUX", ELF_CORE_XFPREG_TYPE, 1897 sizeof(*info->xfpu), info->xfpu); 1898 #endif 1899 1900 return 1; 1901 } 1902 1903 static size_t get_note_info_size(struct elf_note_info *info) 1904 { 1905 int sz = 0; 1906 int i; 1907 1908 for (i = 0; i < info->numnote; i++) 1909 sz += notesize(info->notes + i); 1910 1911 sz += info->thread_status_size; 1912 1913 return sz; 1914 } 1915 1916 static int write_note_info(struct elf_note_info *info, 1917 struct coredump_params *cprm) 1918 { 1919 int i; 1920 struct list_head *t; 1921 1922 for (i = 0; i < info->numnote; i++) 1923 if (!writenote(info->notes + i, cprm)) 1924 return 0; 1925 1926 /* write out the thread status notes section */ 1927 list_for_each(t, &info->thread_list) { 1928 struct elf_thread_status *tmp = 1929 list_entry(t, struct elf_thread_status, list); 1930 1931 for (i = 0; i < tmp->num_notes; i++) 1932 if (!writenote(&tmp->notes[i], cprm)) 1933 return 0; 1934 } 1935 1936 return 1; 1937 } 1938 1939 static void free_note_info(struct elf_note_info *info) 1940 { 1941 while (!list_empty(&info->thread_list)) { 1942 struct list_head *tmp = info->thread_list.next; 1943 list_del(tmp); 1944 kfree(list_entry(tmp, struct elf_thread_status, list)); 1945 } 1946 1947 /* Free data possibly allocated by fill_files_note(): */ 1948 if (info->notes_files) 1949 vfree(info->notes_files->data); 1950 1951 kfree(info->prstatus); 1952 kfree(info->psinfo); 1953 kfree(info->notes); 1954 kfree(info->fpu); 1955 #ifdef ELF_CORE_COPY_XFPREGS 1956 kfree(info->xfpu); 1957 #endif 1958 } 1959 1960 #endif 1961 1962 static struct vm_area_struct *first_vma(struct task_struct *tsk, 1963 struct vm_area_struct *gate_vma) 1964 { 1965 struct vm_area_struct *ret = tsk->mm->mmap; 1966 1967 if (ret) 1968 return ret; 1969 return gate_vma; 1970 } 1971 /* 1972 * Helper function for iterating across a vma list. It ensures that the caller 1973 * will visit `gate_vma' prior to terminating the search. 1974 */ 1975 static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma, 1976 struct vm_area_struct *gate_vma) 1977 { 1978 struct vm_area_struct *ret; 1979 1980 ret = this_vma->vm_next; 1981 if (ret) 1982 return ret; 1983 if (this_vma == gate_vma) 1984 return NULL; 1985 return gate_vma; 1986 } 1987 1988 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum, 1989 elf_addr_t e_shoff, int segs) 1990 { 1991 elf->e_shoff = e_shoff; 1992 elf->e_shentsize = sizeof(*shdr4extnum); 1993 elf->e_shnum = 1; 1994 elf->e_shstrndx = SHN_UNDEF; 1995 1996 memset(shdr4extnum, 0, sizeof(*shdr4extnum)); 1997 1998 shdr4extnum->sh_type = SHT_NULL; 1999 shdr4extnum->sh_size = elf->e_shnum; 2000 shdr4extnum->sh_link = elf->e_shstrndx; 2001 shdr4extnum->sh_info = segs; 2002 } 2003 2004 static size_t elf_core_vma_data_size(struct vm_area_struct *gate_vma, 2005 unsigned long mm_flags) 2006 { 2007 struct vm_area_struct *vma; 2008 size_t size = 0; 2009 2010 for (vma = first_vma(current, gate_vma); vma != NULL; 2011 vma = next_vma(vma, gate_vma)) 2012 size += vma_dump_size(vma, mm_flags); 2013 return size; 2014 } 2015 2016 /* 2017 * Actual dumper 2018 * 2019 * This is a two-pass process; first we find the offsets of the bits, 2020 * and then they are actually written out. If we run out of core limit 2021 * we just truncate. 2022 */ 2023 static int elf_core_dump(struct coredump_params *cprm) 2024 { 2025 int has_dumped = 0; 2026 mm_segment_t fs; 2027 int segs; 2028 struct vm_area_struct *vma, *gate_vma; 2029 struct elfhdr *elf = NULL; 2030 loff_t offset = 0, dataoff; 2031 struct elf_note_info info = { }; 2032 struct elf_phdr *phdr4note = NULL; 2033 struct elf_shdr *shdr4extnum = NULL; 2034 Elf_Half e_phnum; 2035 elf_addr_t e_shoff; 2036 2037 /* 2038 * We no longer stop all VM operations. 2039 * 2040 * This is because those proceses that could possibly change map_count 2041 * or the mmap / vma pages are now blocked in do_exit on current 2042 * finishing this core dump. 2043 * 2044 * Only ptrace can touch these memory addresses, but it doesn't change 2045 * the map_count or the pages allocated. So no possibility of crashing 2046 * exists while dumping the mm->vm_next areas to the core file. 2047 */ 2048 2049 /* alloc memory for large data structures: too large to be on stack */ 2050 elf = kmalloc(sizeof(*elf), GFP_KERNEL); 2051 if (!elf) 2052 goto out; 2053 /* 2054 * The number of segs are recored into ELF header as 16bit value. 2055 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here. 2056 */ 2057 segs = current->mm->map_count; 2058 segs += elf_core_extra_phdrs(); 2059 2060 gate_vma = get_gate_vma(current->mm); 2061 if (gate_vma != NULL) 2062 segs++; 2063 2064 /* for notes section */ 2065 segs++; 2066 2067 /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid 2068 * this, kernel supports extended numbering. Have a look at 2069 * include/linux/elf.h for further information. */ 2070 e_phnum = segs > PN_XNUM ? PN_XNUM : segs; 2071 2072 /* 2073 * Collect all the non-memory information about the process for the 2074 * notes. This also sets up the file header. 2075 */ 2076 if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs)) 2077 goto cleanup; 2078 2079 has_dumped = 1; 2080 2081 fs = get_fs(); 2082 set_fs(KERNEL_DS); 2083 2084 offset += sizeof(*elf); /* Elf header */ 2085 offset += segs * sizeof(struct elf_phdr); /* Program headers */ 2086 2087 /* Write notes phdr entry */ 2088 { 2089 size_t sz = get_note_info_size(&info); 2090 2091 sz += elf_coredump_extra_notes_size(); 2092 2093 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL); 2094 if (!phdr4note) 2095 goto end_coredump; 2096 2097 fill_elf_note_phdr(phdr4note, sz, offset); 2098 offset += sz; 2099 } 2100 2101 dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE); 2102 2103 offset += elf_core_vma_data_size(gate_vma, cprm->mm_flags); 2104 offset += elf_core_extra_data_size(); 2105 e_shoff = offset; 2106 2107 if (e_phnum == PN_XNUM) { 2108 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL); 2109 if (!shdr4extnum) 2110 goto end_coredump; 2111 fill_extnum_info(elf, shdr4extnum, e_shoff, segs); 2112 } 2113 2114 offset = dataoff; 2115 2116 if (!dump_emit(cprm, elf, sizeof(*elf))) 2117 goto end_coredump; 2118 2119 if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) 2120 goto end_coredump; 2121 2122 /* Write program headers for segments dump */ 2123 for (vma = first_vma(current, gate_vma); vma != NULL; 2124 vma = next_vma(vma, gate_vma)) { 2125 struct elf_phdr phdr; 2126 2127 phdr.p_type = PT_LOAD; 2128 phdr.p_offset = offset; 2129 phdr.p_vaddr = vma->vm_start; 2130 phdr.p_paddr = 0; 2131 phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags); 2132 phdr.p_memsz = vma->vm_end - vma->vm_start; 2133 offset += phdr.p_filesz; 2134 phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0; 2135 if (vma->vm_flags & VM_WRITE) 2136 phdr.p_flags |= PF_W; 2137 if (vma->vm_flags & VM_EXEC) 2138 phdr.p_flags |= PF_X; 2139 phdr.p_align = ELF_EXEC_PAGESIZE; 2140 2141 if (!dump_emit(cprm, &phdr, sizeof(phdr))) 2142 goto end_coredump; 2143 } 2144 2145 if (!elf_core_write_extra_phdrs(cprm, offset)) 2146 goto end_coredump; 2147 2148 /* write out the notes section */ 2149 if (!write_note_info(&info, cprm)) 2150 goto end_coredump; 2151 2152 if (elf_coredump_extra_notes_write(cprm)) 2153 goto end_coredump; 2154 2155 /* Align to page */ 2156 if (!dump_skip(cprm, dataoff - cprm->written)) 2157 goto end_coredump; 2158 2159 for (vma = first_vma(current, gate_vma); vma != NULL; 2160 vma = next_vma(vma, gate_vma)) { 2161 unsigned long addr; 2162 unsigned long end; 2163 2164 end = vma->vm_start + vma_dump_size(vma, cprm->mm_flags); 2165 2166 for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) { 2167 struct page *page; 2168 int stop; 2169 2170 page = get_dump_page(addr); 2171 if (page) { 2172 void *kaddr = kmap(page); 2173 stop = !dump_emit(cprm, kaddr, PAGE_SIZE); 2174 kunmap(page); 2175 page_cache_release(page); 2176 } else 2177 stop = !dump_skip(cprm, PAGE_SIZE); 2178 if (stop) 2179 goto end_coredump; 2180 } 2181 } 2182 2183 if (!elf_core_write_extra_data(cprm)) 2184 goto end_coredump; 2185 2186 if (e_phnum == PN_XNUM) { 2187 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum))) 2188 goto end_coredump; 2189 } 2190 2191 end_coredump: 2192 set_fs(fs); 2193 2194 cleanup: 2195 free_note_info(&info); 2196 kfree(shdr4extnum); 2197 kfree(phdr4note); 2198 kfree(elf); 2199 out: 2200 return has_dumped; 2201 } 2202 2203 #endif /* CONFIG_ELF_CORE */ 2204 2205 static int __init init_elf_binfmt(void) 2206 { 2207 register_binfmt(&elf_format); 2208 return 0; 2209 } 2210 2211 static void __exit exit_elf_binfmt(void) 2212 { 2213 /* Remove the COFF and ELF loaders. */ 2214 unregister_binfmt(&elf_format); 2215 } 2216 2217 core_initcall(init_elf_binfmt); 2218 module_exit(exit_elf_binfmt); 2219 MODULE_LICENSE("GPL"); 2220