1 /* binfmt_elf_fdpic.c: FDPIC ELF binary format 2 * 3 * Copyright (C) 2003, 2004 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/mm.h> 19 #include <linux/mman.h> 20 #include <linux/errno.h> 21 #include <linux/signal.h> 22 #include <linux/binfmts.h> 23 #include <linux/string.h> 24 #include <linux/file.h> 25 #include <linux/fcntl.h> 26 #include <linux/slab.h> 27 #include <linux/highmem.h> 28 #include <linux/personality.h> 29 #include <linux/ptrace.h> 30 #include <linux/init.h> 31 #include <linux/smp_lock.h> 32 #include <linux/elf.h> 33 #include <linux/elf-fdpic.h> 34 #include <linux/elfcore.h> 35 36 #include <asm/uaccess.h> 37 #include <asm/param.h> 38 #include <asm/pgalloc.h> 39 40 typedef char *elf_caddr_t; 41 #ifndef elf_addr_t 42 #define elf_addr_t unsigned long 43 #endif 44 45 #if 0 46 #define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ ) 47 #else 48 #define kdebug(fmt, ...) do {} while(0) 49 #endif 50 51 MODULE_LICENSE("GPL"); 52 53 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs); 54 //static int load_elf_fdpic_library(struct file *); 55 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file); 56 static int elf_fdpic_map_file(struct elf_fdpic_params *params, 57 struct file *file, 58 struct mm_struct *mm, 59 const char *what); 60 61 static int create_elf_fdpic_tables(struct linux_binprm *bprm, 62 struct mm_struct *mm, 63 struct elf_fdpic_params *exec_params, 64 struct elf_fdpic_params *interp_params); 65 66 #ifndef CONFIG_MMU 67 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp); 68 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params, 69 struct file *file, 70 struct mm_struct *mm); 71 #endif 72 73 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, 74 struct file *file, 75 struct mm_struct *mm); 76 77 static struct linux_binfmt elf_fdpic_format = { 78 .module = THIS_MODULE, 79 .load_binary = load_elf_fdpic_binary, 80 // .load_shlib = load_elf_fdpic_library, 81 // .core_dump = elf_fdpic_core_dump, 82 .min_coredump = ELF_EXEC_PAGESIZE, 83 }; 84 85 static int __init init_elf_fdpic_binfmt(void) { return register_binfmt(&elf_fdpic_format); } 86 static void __exit exit_elf_fdpic_binfmt(void) { unregister_binfmt(&elf_fdpic_format); } 87 88 module_init(init_elf_fdpic_binfmt) 89 module_exit(exit_elf_fdpic_binfmt) 90 91 static int is_elf_fdpic(struct elfhdr *hdr, struct file *file) 92 { 93 if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0) 94 return 0; 95 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) 96 return 0; 97 if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr)) 98 return 0; 99 if (!file->f_op || !file->f_op->mmap) 100 return 0; 101 return 1; 102 } 103 104 /*****************************************************************************/ 105 /* 106 * read the program headers table into memory 107 */ 108 static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, struct file *file) 109 { 110 struct elf32_phdr *phdr; 111 unsigned long size; 112 int retval, loop; 113 114 if (params->hdr.e_phentsize != sizeof(struct elf_phdr)) 115 return -ENOMEM; 116 if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr)) 117 return -ENOMEM; 118 119 size = params->hdr.e_phnum * sizeof(struct elf_phdr); 120 params->phdrs = kmalloc(size, GFP_KERNEL); 121 if (!params->phdrs) 122 return -ENOMEM; 123 124 retval = kernel_read(file, params->hdr.e_phoff, (char *) params->phdrs, size); 125 if (retval < 0) 126 return retval; 127 128 /* determine stack size for this binary */ 129 phdr = params->phdrs; 130 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 131 if (phdr->p_type != PT_GNU_STACK) 132 continue; 133 134 if (phdr->p_flags & PF_X) 135 params->flags |= ELF_FDPIC_FLAG_EXEC_STACK; 136 else 137 params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK; 138 139 params->stack_size = phdr->p_memsz; 140 break; 141 } 142 143 return 0; 144 } /* end elf_fdpic_fetch_phdrs() */ 145 146 /*****************************************************************************/ 147 /* 148 * load an fdpic binary into various bits of memory 149 */ 150 static int load_elf_fdpic_binary(struct linux_binprm *bprm, struct pt_regs *regs) 151 { 152 struct elf_fdpic_params exec_params, interp_params; 153 struct elf_phdr *phdr; 154 unsigned long stack_size; 155 struct file *interpreter = NULL; /* to shut gcc up */ 156 char *interpreter_name = NULL; 157 int executable_stack; 158 int retval, i; 159 160 memset(&exec_params, 0, sizeof(exec_params)); 161 memset(&interp_params, 0, sizeof(interp_params)); 162 163 exec_params.hdr = *(struct elfhdr *) bprm->buf; 164 exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE; 165 166 /* check that this is a binary we know how to deal with */ 167 retval = -ENOEXEC; 168 if (!is_elf_fdpic(&exec_params.hdr, bprm->file)) 169 goto error; 170 171 /* read the program header table */ 172 retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file); 173 if (retval < 0) 174 goto error; 175 176 /* scan for a program header that specifies an interpreter */ 177 phdr = exec_params.phdrs; 178 179 for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) { 180 switch (phdr->p_type) { 181 case PT_INTERP: 182 retval = -ENOMEM; 183 if (phdr->p_filesz > PATH_MAX) 184 goto error; 185 retval = -ENOENT; 186 if (phdr->p_filesz < 2) 187 goto error; 188 189 /* read the name of the interpreter into memory */ 190 interpreter_name = (char *) kmalloc(phdr->p_filesz, GFP_KERNEL); 191 if (!interpreter_name) 192 goto error; 193 194 retval = kernel_read(bprm->file, 195 phdr->p_offset, 196 interpreter_name, 197 phdr->p_filesz); 198 if (retval < 0) 199 goto error; 200 201 retval = -ENOENT; 202 if (interpreter_name[phdr->p_filesz - 1] != '\0') 203 goto error; 204 205 kdebug("Using ELF interpreter %s", interpreter_name); 206 207 /* replace the program with the interpreter */ 208 interpreter = open_exec(interpreter_name); 209 retval = PTR_ERR(interpreter); 210 if (IS_ERR(interpreter)) { 211 interpreter = NULL; 212 goto error; 213 } 214 215 retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE); 216 if (retval < 0) 217 goto error; 218 219 interp_params.hdr = *((struct elfhdr *) bprm->buf); 220 break; 221 222 case PT_LOAD: 223 #ifdef CONFIG_MMU 224 if (exec_params.load_addr == 0) 225 exec_params.load_addr = phdr->p_vaddr; 226 #endif 227 break; 228 } 229 230 } 231 232 if (elf_check_const_displacement(&exec_params.hdr)) 233 exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP; 234 235 /* perform insanity checks on the interpreter */ 236 if (interpreter_name) { 237 retval = -ELIBBAD; 238 if (!is_elf_fdpic(&interp_params.hdr, interpreter)) 239 goto error; 240 241 interp_params.flags = ELF_FDPIC_FLAG_PRESENT; 242 243 /* read the interpreter's program header table */ 244 retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter); 245 if (retval < 0) 246 goto error; 247 } 248 249 stack_size = exec_params.stack_size; 250 if (stack_size < interp_params.stack_size) 251 stack_size = interp_params.stack_size; 252 253 if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK) 254 executable_stack = EXSTACK_ENABLE_X; 255 else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK) 256 executable_stack = EXSTACK_DISABLE_X; 257 else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK) 258 executable_stack = EXSTACK_ENABLE_X; 259 else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK) 260 executable_stack = EXSTACK_DISABLE_X; 261 else 262 executable_stack = EXSTACK_DEFAULT; 263 264 retval = -ENOEXEC; 265 if (stack_size == 0) 266 goto error; 267 268 if (elf_check_const_displacement(&interp_params.hdr)) 269 interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP; 270 271 /* flush all traces of the currently running executable */ 272 retval = flush_old_exec(bprm); 273 if (retval) 274 goto error; 275 276 /* there's now no turning back... the old userspace image is dead, 277 * defunct, deceased, etc. after this point we have to exit via 278 * error_kill */ 279 set_personality(PER_LINUX_FDPIC); 280 set_binfmt(&elf_fdpic_format); 281 282 current->mm->start_code = 0; 283 current->mm->end_code = 0; 284 current->mm->start_stack = 0; 285 current->mm->start_data = 0; 286 current->mm->end_data = 0; 287 current->mm->context.exec_fdpic_loadmap = 0; 288 current->mm->context.interp_fdpic_loadmap = 0; 289 290 current->flags &= ~PF_FORKNOEXEC; 291 292 #ifdef CONFIG_MMU 293 elf_fdpic_arch_lay_out_mm(&exec_params, 294 &interp_params, 295 ¤t->mm->start_stack, 296 ¤t->mm->start_brk); 297 298 retval = setup_arg_pages(bprm, current->mm->start_stack, executable_stack); 299 if (retval < 0) { 300 send_sig(SIGKILL, current, 0); 301 goto error_kill; 302 } 303 #endif 304 305 /* load the executable and interpreter into memory */ 306 retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm, "executable"); 307 if (retval < 0) 308 goto error_kill; 309 310 if (interpreter_name) { 311 retval = elf_fdpic_map_file(&interp_params, interpreter, 312 current->mm, "interpreter"); 313 if (retval < 0) { 314 printk(KERN_ERR "Unable to load interpreter\n"); 315 goto error_kill; 316 } 317 318 allow_write_access(interpreter); 319 fput(interpreter); 320 interpreter = NULL; 321 } 322 323 #ifdef CONFIG_MMU 324 if (!current->mm->start_brk) 325 current->mm->start_brk = current->mm->end_data; 326 327 current->mm->brk = current->mm->start_brk = PAGE_ALIGN(current->mm->start_brk); 328 329 #else 330 /* create a stack and brk area big enough for everyone 331 * - the brk heap starts at the bottom and works up 332 * - the stack starts at the top and works down 333 */ 334 stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK; 335 if (stack_size < PAGE_SIZE * 2) 336 stack_size = PAGE_SIZE * 2; 337 338 down_write(¤t->mm->mmap_sem); 339 current->mm->start_brk = do_mmap(NULL, 340 0, 341 stack_size, 342 PROT_READ | PROT_WRITE | PROT_EXEC, 343 MAP_PRIVATE | MAP_ANON | MAP_GROWSDOWN, 344 0); 345 346 if (IS_ERR((void *) current->mm->start_brk)) { 347 up_write(¤t->mm->mmap_sem); 348 retval = current->mm->start_brk; 349 current->mm->start_brk = 0; 350 goto error_kill; 351 } 352 353 if (do_mremap(current->mm->start_brk, 354 stack_size, 355 ksize((char *) current->mm->start_brk), 356 0, 0 357 ) == current->mm->start_brk 358 ) 359 stack_size = ksize((char *) current->mm->start_brk); 360 up_write(¤t->mm->mmap_sem); 361 362 current->mm->brk = current->mm->start_brk; 363 current->mm->context.end_brk = current->mm->start_brk; 364 current->mm->context.end_brk += (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0; 365 current->mm->start_stack = current->mm->start_brk + stack_size; 366 #endif 367 368 compute_creds(bprm); 369 current->flags &= ~PF_FORKNOEXEC; 370 if (create_elf_fdpic_tables(bprm, current->mm, &exec_params, &interp_params) < 0) 371 goto error_kill; 372 373 kdebug("- start_code %lx", (long) current->mm->start_code); 374 kdebug("- end_code %lx", (long) current->mm->end_code); 375 kdebug("- start_data %lx", (long) current->mm->start_data); 376 kdebug("- end_data %lx", (long) current->mm->end_data); 377 kdebug("- start_brk %lx", (long) current->mm->start_brk); 378 kdebug("- brk %lx", (long) current->mm->brk); 379 kdebug("- start_stack %lx", (long) current->mm->start_stack); 380 381 #ifdef ELF_FDPIC_PLAT_INIT 382 /* 383 * The ABI may specify that certain registers be set up in special 384 * ways (on i386 %edx is the address of a DT_FINI function, for 385 * example. This macro performs whatever initialization to 386 * the regs structure is required. 387 */ 388 ELF_FDPIC_PLAT_INIT(regs, 389 exec_params.map_addr, 390 interp_params.map_addr, 391 interp_params.dynamic_addr ?: exec_params.dynamic_addr 392 ); 393 #endif 394 395 /* everything is now ready... get the userspace context ready to roll */ 396 start_thread(regs, 397 interp_params.entry_addr ?: exec_params.entry_addr, 398 current->mm->start_stack); 399 400 if (unlikely(current->ptrace & PT_PTRACED)) { 401 if (current->ptrace & PT_TRACE_EXEC) 402 ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP); 403 else 404 send_sig(SIGTRAP, current, 0); 405 } 406 407 retval = 0; 408 409 error: 410 if (interpreter) { 411 allow_write_access(interpreter); 412 fput(interpreter); 413 } 414 kfree(interpreter_name); 415 kfree(exec_params.phdrs); 416 kfree(exec_params.loadmap); 417 kfree(interp_params.phdrs); 418 kfree(interp_params.loadmap); 419 return retval; 420 421 /* unrecoverable error - kill the process */ 422 error_kill: 423 send_sig(SIGSEGV, current, 0); 424 goto error; 425 426 } /* end load_elf_fdpic_binary() */ 427 428 /*****************************************************************************/ 429 /* 430 * present useful information to the program 431 */ 432 static int create_elf_fdpic_tables(struct linux_binprm *bprm, 433 struct mm_struct *mm, 434 struct elf_fdpic_params *exec_params, 435 struct elf_fdpic_params *interp_params) 436 { 437 unsigned long sp, csp, nitems; 438 elf_caddr_t *argv, *envp; 439 size_t platform_len = 0, len; 440 char *k_platform, *u_platform, *p; 441 long hwcap; 442 int loop; 443 444 /* we're going to shovel a whole load of stuff onto the stack */ 445 #ifdef CONFIG_MMU 446 sp = bprm->p; 447 #else 448 sp = mm->start_stack; 449 450 /* stack the program arguments and environment */ 451 if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0) 452 return -EFAULT; 453 #endif 454 455 /* get hold of platform and hardware capabilities masks for the machine 456 * we are running on. In some cases (Sparc), this info is impossible 457 * to get, in others (i386) it is merely difficult. 458 */ 459 hwcap = ELF_HWCAP; 460 k_platform = ELF_PLATFORM; 461 462 if (k_platform) { 463 platform_len = strlen(k_platform) + 1; 464 sp -= platform_len; 465 if (__copy_to_user(u_platform, k_platform, platform_len) != 0) 466 return -EFAULT; 467 } 468 469 u_platform = (char *) sp; 470 471 #if defined(__i386__) && defined(CONFIG_SMP) 472 /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions 473 * by the processes running on the same package. One thing we can do 474 * is to shuffle the initial stack for them. 475 * 476 * the conditionals here are unneeded, but kept in to make the 477 * code behaviour the same as pre change unless we have hyperthreaded 478 * processors. This keeps Mr Marcelo Person happier but should be 479 * removed for 2.5 480 */ 481 if (smp_num_siblings > 1) 482 sp = sp - ((current->pid % 64) << 7); 483 #endif 484 485 sp &= ~7UL; 486 487 /* stack the load map(s) */ 488 len = sizeof(struct elf32_fdpic_loadmap); 489 len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs; 490 sp = (sp - len) & ~7UL; 491 exec_params->map_addr = sp; 492 493 if (copy_to_user((void *) sp, exec_params->loadmap, len) != 0) 494 return -EFAULT; 495 496 current->mm->context.exec_fdpic_loadmap = (unsigned long) sp; 497 498 if (interp_params->loadmap) { 499 len = sizeof(struct elf32_fdpic_loadmap); 500 len += sizeof(struct elf32_fdpic_loadseg) * interp_params->loadmap->nsegs; 501 sp = (sp - len) & ~7UL; 502 interp_params->map_addr = sp; 503 504 if (copy_to_user((void *) sp, interp_params->loadmap, len) != 0) 505 return -EFAULT; 506 507 current->mm->context.interp_fdpic_loadmap = (unsigned long) sp; 508 } 509 510 /* force 16 byte _final_ alignment here for generality */ 511 #define DLINFO_ITEMS 13 512 513 nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0); 514 #ifdef DLINFO_ARCH_ITEMS 515 nitems += DLINFO_ARCH_ITEMS; 516 #endif 517 518 csp = sp; 519 sp -= nitems * 2 * sizeof(unsigned long); 520 sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */ 521 sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */ 522 sp -= 1 * sizeof(unsigned long); /* argc */ 523 524 csp -= sp & 15UL; 525 sp -= sp & 15UL; 526 527 /* put the ELF interpreter info on the stack */ 528 #define NEW_AUX_ENT(nr, id, val) \ 529 do { \ 530 struct { unsigned long _id, _val; } *ent = (void *) csp; \ 531 __put_user((id), &ent[nr]._id); \ 532 __put_user((val), &ent[nr]._val); \ 533 } while (0) 534 535 csp -= 2 * sizeof(unsigned long); 536 NEW_AUX_ENT(0, AT_NULL, 0); 537 if (k_platform) { 538 csp -= 2 * sizeof(unsigned long); 539 NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform); 540 } 541 542 csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long); 543 NEW_AUX_ENT( 0, AT_HWCAP, hwcap); 544 NEW_AUX_ENT( 1, AT_PAGESZ, PAGE_SIZE); 545 NEW_AUX_ENT( 2, AT_CLKTCK, CLOCKS_PER_SEC); 546 NEW_AUX_ENT( 3, AT_PHDR, exec_params->ph_addr); 547 NEW_AUX_ENT( 4, AT_PHENT, sizeof(struct elf_phdr)); 548 NEW_AUX_ENT( 5, AT_PHNUM, exec_params->hdr.e_phnum); 549 NEW_AUX_ENT( 6, AT_BASE, interp_params->elfhdr_addr); 550 NEW_AUX_ENT( 7, AT_FLAGS, 0); 551 NEW_AUX_ENT( 8, AT_ENTRY, exec_params->entry_addr); 552 NEW_AUX_ENT( 9, AT_UID, (elf_addr_t) current->uid); 553 NEW_AUX_ENT(10, AT_EUID, (elf_addr_t) current->euid); 554 NEW_AUX_ENT(11, AT_GID, (elf_addr_t) current->gid); 555 NEW_AUX_ENT(12, AT_EGID, (elf_addr_t) current->egid); 556 557 #ifdef ARCH_DLINFO 558 /* ARCH_DLINFO must come last so platform specific code can enforce 559 * special alignment requirements on the AUXV if necessary (eg. PPC). 560 */ 561 ARCH_DLINFO; 562 #endif 563 #undef NEW_AUX_ENT 564 565 /* allocate room for argv[] and envv[] */ 566 csp -= (bprm->envc + 1) * sizeof(elf_caddr_t); 567 envp = (elf_caddr_t *) csp; 568 csp -= (bprm->argc + 1) * sizeof(elf_caddr_t); 569 argv = (elf_caddr_t *) csp; 570 571 /* stack argc */ 572 csp -= sizeof(unsigned long); 573 __put_user(bprm->argc, (unsigned long *) csp); 574 575 if (csp != sp) 576 BUG(); 577 578 /* fill in the argv[] array */ 579 #ifdef CONFIG_MMU 580 current->mm->arg_start = bprm->p; 581 #else 582 current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p); 583 #endif 584 585 p = (char *) current->mm->arg_start; 586 for (loop = bprm->argc; loop > 0; loop--) { 587 __put_user((elf_caddr_t) p, argv++); 588 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES); 589 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES) 590 return -EINVAL; 591 p += len; 592 } 593 __put_user(NULL, argv); 594 current->mm->arg_end = (unsigned long) p; 595 596 /* fill in the envv[] array */ 597 current->mm->env_start = (unsigned long) p; 598 for (loop = bprm->envc; loop > 0; loop--) { 599 __put_user((elf_caddr_t)(unsigned long) p, envp++); 600 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES); 601 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES) 602 return -EINVAL; 603 p += len; 604 } 605 __put_user(NULL, envp); 606 current->mm->env_end = (unsigned long) p; 607 608 mm->start_stack = (unsigned long) sp; 609 return 0; 610 } /* end create_elf_fdpic_tables() */ 611 612 /*****************************************************************************/ 613 /* 614 * transfer the program arguments and environment from the holding pages onto 615 * the stack 616 */ 617 #ifndef CONFIG_MMU 618 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp) 619 { 620 unsigned long index, stop, sp; 621 char *src; 622 int ret = 0; 623 624 stop = bprm->p >> PAGE_SHIFT; 625 sp = *_sp; 626 627 for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { 628 src = kmap(bprm->page[index]); 629 sp -= PAGE_SIZE; 630 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0) 631 ret = -EFAULT; 632 kunmap(bprm->page[index]); 633 if (ret < 0) 634 goto out; 635 } 636 637 *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15; 638 639 out: 640 return ret; 641 } /* end elf_fdpic_transfer_args_to_stack() */ 642 #endif 643 644 /*****************************************************************************/ 645 /* 646 * load the appropriate binary image (executable or interpreter) into memory 647 * - we assume no MMU is available 648 * - if no other PIC bits are set in params->hdr->e_flags 649 * - we assume that the LOADable segments in the binary are independently relocatable 650 * - we assume R/O executable segments are shareable 651 * - else 652 * - we assume the loadable parts of the image to require fixed displacement 653 * - the image is not shareable 654 */ 655 static int elf_fdpic_map_file(struct elf_fdpic_params *params, 656 struct file *file, 657 struct mm_struct *mm, 658 const char *what) 659 { 660 struct elf32_fdpic_loadmap *loadmap; 661 #ifdef CONFIG_MMU 662 struct elf32_fdpic_loadseg *mseg; 663 #endif 664 struct elf32_fdpic_loadseg *seg; 665 struct elf32_phdr *phdr; 666 unsigned long load_addr, stop; 667 unsigned nloads, tmp; 668 size_t size; 669 int loop, ret; 670 671 /* allocate a load map table */ 672 nloads = 0; 673 for (loop = 0; loop < params->hdr.e_phnum; loop++) 674 if (params->phdrs[loop].p_type == PT_LOAD) 675 nloads++; 676 677 if (nloads == 0) 678 return -ELIBBAD; 679 680 size = sizeof(*loadmap) + nloads * sizeof(*seg); 681 loadmap = kmalloc(size, GFP_KERNEL); 682 if (!loadmap) 683 return -ENOMEM; 684 685 params->loadmap = loadmap; 686 memset(loadmap, 0, size); 687 688 loadmap->version = ELF32_FDPIC_LOADMAP_VERSION; 689 loadmap->nsegs = nloads; 690 691 load_addr = params->load_addr; 692 seg = loadmap->segs; 693 694 /* map the requested LOADs into the memory space */ 695 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) { 696 case ELF_FDPIC_FLAG_CONSTDISP: 697 case ELF_FDPIC_FLAG_CONTIGUOUS: 698 #ifndef CONFIG_MMU 699 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm); 700 if (ret < 0) 701 return ret; 702 break; 703 #endif 704 default: 705 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm); 706 if (ret < 0) 707 return ret; 708 break; 709 } 710 711 /* map the entry point */ 712 if (params->hdr.e_entry) { 713 seg = loadmap->segs; 714 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) { 715 if (params->hdr.e_entry >= seg->p_vaddr && 716 params->hdr.e_entry < seg->p_vaddr + seg->p_memsz 717 ) { 718 params->entry_addr = 719 (params->hdr.e_entry - seg->p_vaddr) + seg->addr; 720 break; 721 } 722 } 723 } 724 725 /* determine where the program header table has wound up if mapped */ 726 stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr); 727 phdr = params->phdrs; 728 729 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 730 if (phdr->p_type != PT_LOAD) 731 continue; 732 733 if (phdr->p_offset > params->hdr.e_phoff || 734 phdr->p_offset + phdr->p_filesz < stop) 735 continue; 736 737 seg = loadmap->segs; 738 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) { 739 if (phdr->p_vaddr >= seg->p_vaddr && 740 phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz 741 ) { 742 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr + 743 params->hdr.e_phoff - phdr->p_offset; 744 break; 745 } 746 } 747 break; 748 } 749 750 /* determine where the dynamic section has wound up if there is one */ 751 phdr = params->phdrs; 752 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 753 if (phdr->p_type != PT_DYNAMIC) 754 continue; 755 756 seg = loadmap->segs; 757 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) { 758 if (phdr->p_vaddr >= seg->p_vaddr && 759 phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz 760 ) { 761 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr; 762 763 /* check the dynamic section contains at least one item, and that 764 * the last item is a NULL entry */ 765 if (phdr->p_memsz == 0 || 766 phdr->p_memsz % sizeof(Elf32_Dyn) != 0) 767 goto dynamic_error; 768 769 tmp = phdr->p_memsz / sizeof(Elf32_Dyn); 770 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0) 771 goto dynamic_error; 772 break; 773 } 774 } 775 break; 776 } 777 778 /* now elide adjacent segments in the load map on MMU linux 779 * - on uClinux the holes between may actually be filled with system stuff or stuff from 780 * other processes 781 */ 782 #ifdef CONFIG_MMU 783 nloads = loadmap->nsegs; 784 mseg = loadmap->segs; 785 seg = mseg + 1; 786 for (loop = 1; loop < nloads; loop++) { 787 /* see if we have a candidate for merging */ 788 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) { 789 load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz); 790 if (load_addr == (seg->addr & PAGE_MASK)) { 791 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz); 792 mseg->p_memsz += seg->addr & ~PAGE_MASK; 793 mseg->p_memsz += seg->p_memsz; 794 loadmap->nsegs--; 795 continue; 796 } 797 } 798 799 mseg++; 800 if (mseg != seg) 801 *mseg = *seg; 802 } 803 #endif 804 805 kdebug("Mapped Object [%s]:", what); 806 kdebug("- elfhdr : %lx", params->elfhdr_addr); 807 kdebug("- entry : %lx", params->entry_addr); 808 kdebug("- PHDR[] : %lx", params->ph_addr); 809 kdebug("- DYNAMIC[]: %lx", params->dynamic_addr); 810 seg = loadmap->segs; 811 for (loop = 0; loop < loadmap->nsegs; loop++, seg++) 812 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]", 813 loop, 814 seg->addr, seg->addr + seg->p_memsz - 1, 815 seg->p_vaddr, seg->p_memsz); 816 817 return 0; 818 819 dynamic_error: 820 printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n", 821 what, file->f_dentry->d_inode->i_ino); 822 return -ELIBBAD; 823 } /* end elf_fdpic_map_file() */ 824 825 /*****************************************************************************/ 826 /* 827 * map a file with constant displacement under uClinux 828 */ 829 #ifndef CONFIG_MMU 830 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params, 831 struct file *file, 832 struct mm_struct *mm) 833 { 834 struct elf32_fdpic_loadseg *seg; 835 struct elf32_phdr *phdr; 836 unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags; 837 loff_t fpos; 838 int loop, ret; 839 840 load_addr = params->load_addr; 841 seg = params->loadmap->segs; 842 843 /* determine the bounds of the contiguous overall allocation we must make */ 844 phdr = params->phdrs; 845 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 846 if (params->phdrs[loop].p_type != PT_LOAD) 847 continue; 848 849 if (base > phdr->p_vaddr) 850 base = phdr->p_vaddr; 851 if (top < phdr->p_vaddr + phdr->p_memsz) 852 top = phdr->p_vaddr + phdr->p_memsz; 853 } 854 855 /* allocate one big anon block for everything */ 856 mflags = MAP_PRIVATE; 857 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE) 858 mflags |= MAP_EXECUTABLE; 859 860 down_write(&mm->mmap_sem); 861 maddr = do_mmap(NULL, load_addr, top - base, 862 PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0); 863 up_write(&mm->mmap_sem); 864 if (IS_ERR((void *) maddr)) 865 return (int) maddr; 866 867 if (load_addr != 0) 868 load_addr += PAGE_ALIGN(top - base); 869 870 /* and then load the file segments into it */ 871 phdr = params->phdrs; 872 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 873 if (params->phdrs[loop].p_type != PT_LOAD) 874 continue; 875 876 fpos = phdr->p_offset; 877 878 seg->addr = maddr + (phdr->p_vaddr - base); 879 seg->p_vaddr = phdr->p_vaddr; 880 seg->p_memsz = phdr->p_memsz; 881 882 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos); 883 if (ret < 0) 884 return ret; 885 886 /* map the ELF header address if in this segment */ 887 if (phdr->p_offset == 0) 888 params->elfhdr_addr = seg->addr; 889 890 /* clear any space allocated but not loaded */ 891 if (phdr->p_filesz < phdr->p_memsz) 892 clear_user((void *) (seg->addr + phdr->p_filesz), 893 phdr->p_memsz - phdr->p_filesz); 894 895 if (mm) { 896 if (phdr->p_flags & PF_X) { 897 mm->start_code = seg->addr; 898 mm->end_code = seg->addr + phdr->p_memsz; 899 } 900 else if (!mm->start_data) { 901 mm->start_data = seg->addr; 902 #ifndef CONFIG_MMU 903 mm->end_data = seg->addr + phdr->p_memsz; 904 #endif 905 } 906 907 #ifdef CONFIG_MMU 908 if (seg->addr + phdr->p_memsz > mm->end_data) 909 mm->end_data = seg->addr + phdr->p_memsz; 910 #endif 911 } 912 913 seg++; 914 } 915 916 return 0; 917 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */ 918 #endif 919 920 /*****************************************************************************/ 921 /* 922 * map a binary by direct mmap() of the individual PT_LOAD segments 923 */ 924 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, 925 struct file *file, 926 struct mm_struct *mm) 927 { 928 struct elf32_fdpic_loadseg *seg; 929 struct elf32_phdr *phdr; 930 unsigned long load_addr, delta_vaddr; 931 int loop, dvset; 932 933 load_addr = params->load_addr; 934 delta_vaddr = 0; 935 dvset = 0; 936 937 seg = params->loadmap->segs; 938 939 /* deal with each load segment separately */ 940 phdr = params->phdrs; 941 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 942 unsigned long maddr, disp, excess, excess1; 943 int prot = 0, flags; 944 945 if (phdr->p_type != PT_LOAD) 946 continue; 947 948 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx", 949 (unsigned long) phdr->p_vaddr, 950 (unsigned long) phdr->p_offset, 951 (unsigned long) phdr->p_filesz, 952 (unsigned long) phdr->p_memsz); 953 954 /* determine the mapping parameters */ 955 if (phdr->p_flags & PF_R) prot |= PROT_READ; 956 if (phdr->p_flags & PF_W) prot |= PROT_WRITE; 957 if (phdr->p_flags & PF_X) prot |= PROT_EXEC; 958 959 flags = MAP_PRIVATE | MAP_DENYWRITE; 960 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE) 961 flags |= MAP_EXECUTABLE; 962 963 maddr = 0; 964 965 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) { 966 case ELF_FDPIC_FLAG_INDEPENDENT: 967 /* PT_LOADs are independently locatable */ 968 break; 969 970 case ELF_FDPIC_FLAG_HONOURVADDR: 971 /* the specified virtual address must be honoured */ 972 maddr = phdr->p_vaddr; 973 flags |= MAP_FIXED; 974 break; 975 976 case ELF_FDPIC_FLAG_CONSTDISP: 977 /* constant displacement 978 * - can be mapped anywhere, but must be mapped as a unit 979 */ 980 if (!dvset) { 981 maddr = load_addr; 982 delta_vaddr = phdr->p_vaddr; 983 dvset = 1; 984 } 985 else { 986 maddr = load_addr + phdr->p_vaddr - delta_vaddr; 987 flags |= MAP_FIXED; 988 } 989 break; 990 991 case ELF_FDPIC_FLAG_CONTIGUOUS: 992 /* contiguity handled later */ 993 break; 994 995 default: 996 BUG(); 997 } 998 999 maddr &= PAGE_MASK; 1000 1001 /* create the mapping */ 1002 disp = phdr->p_vaddr & ~PAGE_MASK; 1003 down_write(&mm->mmap_sem); 1004 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags, 1005 phdr->p_offset - disp); 1006 up_write(&mm->mmap_sem); 1007 1008 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx", 1009 loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp, 1010 maddr); 1011 1012 if (IS_ERR((void *) maddr)) 1013 return (int) maddr; 1014 1015 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS) 1016 load_addr += PAGE_ALIGN(phdr->p_memsz + disp); 1017 1018 seg->addr = maddr + disp; 1019 seg->p_vaddr = phdr->p_vaddr; 1020 seg->p_memsz = phdr->p_memsz; 1021 1022 /* map the ELF header address if in this segment */ 1023 if (phdr->p_offset == 0) 1024 params->elfhdr_addr = seg->addr; 1025 1026 /* clear the bit between beginning of mapping and beginning of PT_LOAD */ 1027 if (prot & PROT_WRITE && disp > 0) { 1028 kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp); 1029 clear_user((void *) maddr, disp); 1030 maddr += disp; 1031 } 1032 1033 /* clear any space allocated but not loaded 1034 * - on uClinux we can just clear the lot 1035 * - on MMU linux we'll get a SIGBUS beyond the last page 1036 * extant in the file 1037 */ 1038 excess = phdr->p_memsz - phdr->p_filesz; 1039 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK); 1040 1041 #ifdef CONFIG_MMU 1042 1043 if (excess > excess1) { 1044 unsigned long xaddr = maddr + phdr->p_filesz + excess1; 1045 unsigned long xmaddr; 1046 1047 flags |= MAP_FIXED | MAP_ANONYMOUS; 1048 down_write(&mm->mmap_sem); 1049 xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0); 1050 up_write(&mm->mmap_sem); 1051 1052 kdebug("mmap[%d] <anon>" 1053 " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx", 1054 loop, xaddr, excess - excess1, prot, flags, xmaddr); 1055 1056 if (xmaddr != xaddr) 1057 return -ENOMEM; 1058 } 1059 1060 if (prot & PROT_WRITE && excess1 > 0) { 1061 kdebug("clear[%d] ad=%lx sz=%lx", 1062 loop, maddr + phdr->p_filesz, excess1); 1063 clear_user((void *) maddr + phdr->p_filesz, excess1); 1064 } 1065 1066 #else 1067 if (excess > 0) { 1068 kdebug("clear[%d] ad=%lx sz=%lx", 1069 loop, maddr + phdr->p_filesz, excess); 1070 clear_user((void *) maddr + phdr->p_filesz, excess); 1071 } 1072 #endif 1073 1074 if (mm) { 1075 if (phdr->p_flags & PF_X) { 1076 mm->start_code = maddr; 1077 mm->end_code = maddr + phdr->p_memsz; 1078 } 1079 else if (!mm->start_data) { 1080 mm->start_data = maddr; 1081 mm->end_data = maddr + phdr->p_memsz; 1082 } 1083 } 1084 1085 seg++; 1086 } 1087 1088 return 0; 1089 } /* end elf_fdpic_map_file_by_direct_mmap() */ 1090