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 = 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 __user *argv, *envp; 439 size_t platform_len = 0, len; 440 char *k_platform; 441 char __user *u_platform, *p; 442 long hwcap; 443 int loop; 444 445 /* we're going to shovel a whole load of stuff onto the stack */ 446 #ifdef CONFIG_MMU 447 sp = bprm->p; 448 #else 449 sp = mm->start_stack; 450 451 /* stack the program arguments and environment */ 452 if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0) 453 return -EFAULT; 454 #endif 455 456 /* get hold of platform and hardware capabilities masks for the machine 457 * we are running on. In some cases (Sparc), this info is impossible 458 * to get, in others (i386) it is merely difficult. 459 */ 460 hwcap = ELF_HWCAP; 461 k_platform = ELF_PLATFORM; 462 463 if (k_platform) { 464 platform_len = strlen(k_platform) + 1; 465 sp -= platform_len; 466 u_platform = (char __user *) sp; 467 if (__copy_to_user(u_platform, k_platform, platform_len) != 0) 468 return -EFAULT; 469 } 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 __user *) 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 __user *) 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; } __user *ent = (void __user *) 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 __user *) csp; 568 csp -= (bprm->argc + 1) * sizeof(elf_caddr_t); 569 argv = (elf_caddr_t __user *) csp; 570 571 /* stack argc */ 572 csp -= sizeof(unsigned long); 573 __put_user(bprm->argc, (unsigned long __user *) csp); 574 575 BUG_ON(csp != sp); 576 577 /* fill in the argv[] array */ 578 #ifdef CONFIG_MMU 579 current->mm->arg_start = bprm->p; 580 #else 581 current->mm->arg_start = current->mm->start_stack - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p); 582 #endif 583 584 p = (char __user *) current->mm->arg_start; 585 for (loop = bprm->argc; loop > 0; loop--) { 586 __put_user((elf_caddr_t) p, argv++); 587 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES); 588 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES) 589 return -EINVAL; 590 p += len; 591 } 592 __put_user(NULL, argv); 593 current->mm->arg_end = (unsigned long) p; 594 595 /* fill in the envv[] array */ 596 current->mm->env_start = (unsigned long) p; 597 for (loop = bprm->envc; loop > 0; loop--) { 598 __put_user((elf_caddr_t)(unsigned long) p, envp++); 599 len = strnlen_user(p, PAGE_SIZE * MAX_ARG_PAGES); 600 if (!len || len > PAGE_SIZE * MAX_ARG_PAGES) 601 return -EINVAL; 602 p += len; 603 } 604 __put_user(NULL, envp); 605 current->mm->env_end = (unsigned long) p; 606 607 mm->start_stack = (unsigned long) sp; 608 return 0; 609 } /* end create_elf_fdpic_tables() */ 610 611 /*****************************************************************************/ 612 /* 613 * transfer the program arguments and environment from the holding pages onto 614 * the stack 615 */ 616 #ifndef CONFIG_MMU 617 static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm, unsigned long *_sp) 618 { 619 unsigned long index, stop, sp; 620 char *src; 621 int ret = 0; 622 623 stop = bprm->p >> PAGE_SHIFT; 624 sp = *_sp; 625 626 for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { 627 src = kmap(bprm->page[index]); 628 sp -= PAGE_SIZE; 629 if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0) 630 ret = -EFAULT; 631 kunmap(bprm->page[index]); 632 if (ret < 0) 633 goto out; 634 } 635 636 *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15; 637 638 out: 639 return ret; 640 } /* end elf_fdpic_transfer_args_to_stack() */ 641 #endif 642 643 /*****************************************************************************/ 644 /* 645 * load the appropriate binary image (executable or interpreter) into memory 646 * - we assume no MMU is available 647 * - if no other PIC bits are set in params->hdr->e_flags 648 * - we assume that the LOADable segments in the binary are independently relocatable 649 * - we assume R/O executable segments are shareable 650 * - else 651 * - we assume the loadable parts of the image to require fixed displacement 652 * - the image is not shareable 653 */ 654 static int elf_fdpic_map_file(struct elf_fdpic_params *params, 655 struct file *file, 656 struct mm_struct *mm, 657 const char *what) 658 { 659 struct elf32_fdpic_loadmap *loadmap; 660 #ifdef CONFIG_MMU 661 struct elf32_fdpic_loadseg *mseg; 662 #endif 663 struct elf32_fdpic_loadseg *seg; 664 struct elf32_phdr *phdr; 665 unsigned long load_addr, stop; 666 unsigned nloads, tmp; 667 size_t size; 668 int loop, ret; 669 670 /* allocate a load map table */ 671 nloads = 0; 672 for (loop = 0; loop < params->hdr.e_phnum; loop++) 673 if (params->phdrs[loop].p_type == PT_LOAD) 674 nloads++; 675 676 if (nloads == 0) 677 return -ELIBBAD; 678 679 size = sizeof(*loadmap) + nloads * sizeof(*seg); 680 loadmap = kmalloc(size, GFP_KERNEL); 681 if (!loadmap) 682 return -ENOMEM; 683 684 params->loadmap = loadmap; 685 memset(loadmap, 0, size); 686 687 loadmap->version = ELF32_FDPIC_LOADMAP_VERSION; 688 loadmap->nsegs = nloads; 689 690 load_addr = params->load_addr; 691 seg = loadmap->segs; 692 693 /* map the requested LOADs into the memory space */ 694 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) { 695 case ELF_FDPIC_FLAG_CONSTDISP: 696 case ELF_FDPIC_FLAG_CONTIGUOUS: 697 #ifndef CONFIG_MMU 698 ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm); 699 if (ret < 0) 700 return ret; 701 break; 702 #endif 703 default: 704 ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm); 705 if (ret < 0) 706 return ret; 707 break; 708 } 709 710 /* map the entry point */ 711 if (params->hdr.e_entry) { 712 seg = loadmap->segs; 713 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) { 714 if (params->hdr.e_entry >= seg->p_vaddr && 715 params->hdr.e_entry < seg->p_vaddr + seg->p_memsz 716 ) { 717 params->entry_addr = 718 (params->hdr.e_entry - seg->p_vaddr) + seg->addr; 719 break; 720 } 721 } 722 } 723 724 /* determine where the program header table has wound up if mapped */ 725 stop = params->hdr.e_phoff + params->hdr.e_phnum * sizeof (struct elf_phdr); 726 phdr = params->phdrs; 727 728 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 729 if (phdr->p_type != PT_LOAD) 730 continue; 731 732 if (phdr->p_offset > params->hdr.e_phoff || 733 phdr->p_offset + phdr->p_filesz < stop) 734 continue; 735 736 seg = loadmap->segs; 737 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) { 738 if (phdr->p_vaddr >= seg->p_vaddr && 739 phdr->p_vaddr + phdr->p_filesz <= seg->p_vaddr + seg->p_memsz 740 ) { 741 params->ph_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr + 742 params->hdr.e_phoff - phdr->p_offset; 743 break; 744 } 745 } 746 break; 747 } 748 749 /* determine where the dynamic section has wound up if there is one */ 750 phdr = params->phdrs; 751 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 752 if (phdr->p_type != PT_DYNAMIC) 753 continue; 754 755 seg = loadmap->segs; 756 for (loop = loadmap->nsegs; loop > 0; loop--, seg++) { 757 if (phdr->p_vaddr >= seg->p_vaddr && 758 phdr->p_vaddr + phdr->p_memsz <= seg->p_vaddr + seg->p_memsz 759 ) { 760 params->dynamic_addr = (phdr->p_vaddr - seg->p_vaddr) + seg->addr; 761 762 /* check the dynamic section contains at least one item, and that 763 * the last item is a NULL entry */ 764 if (phdr->p_memsz == 0 || 765 phdr->p_memsz % sizeof(Elf32_Dyn) != 0) 766 goto dynamic_error; 767 768 tmp = phdr->p_memsz / sizeof(Elf32_Dyn); 769 if (((Elf32_Dyn *) params->dynamic_addr)[tmp - 1].d_tag != 0) 770 goto dynamic_error; 771 break; 772 } 773 } 774 break; 775 } 776 777 /* now elide adjacent segments in the load map on MMU linux 778 * - on uClinux the holes between may actually be filled with system stuff or stuff from 779 * other processes 780 */ 781 #ifdef CONFIG_MMU 782 nloads = loadmap->nsegs; 783 mseg = loadmap->segs; 784 seg = mseg + 1; 785 for (loop = 1; loop < nloads; loop++) { 786 /* see if we have a candidate for merging */ 787 if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) { 788 load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz); 789 if (load_addr == (seg->addr & PAGE_MASK)) { 790 mseg->p_memsz += load_addr - (mseg->addr + mseg->p_memsz); 791 mseg->p_memsz += seg->addr & ~PAGE_MASK; 792 mseg->p_memsz += seg->p_memsz; 793 loadmap->nsegs--; 794 continue; 795 } 796 } 797 798 mseg++; 799 if (mseg != seg) 800 *mseg = *seg; 801 } 802 #endif 803 804 kdebug("Mapped Object [%s]:", what); 805 kdebug("- elfhdr : %lx", params->elfhdr_addr); 806 kdebug("- entry : %lx", params->entry_addr); 807 kdebug("- PHDR[] : %lx", params->ph_addr); 808 kdebug("- DYNAMIC[]: %lx", params->dynamic_addr); 809 seg = loadmap->segs; 810 for (loop = 0; loop < loadmap->nsegs; loop++, seg++) 811 kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]", 812 loop, 813 seg->addr, seg->addr + seg->p_memsz - 1, 814 seg->p_vaddr, seg->p_memsz); 815 816 return 0; 817 818 dynamic_error: 819 printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n", 820 what, file->f_dentry->d_inode->i_ino); 821 return -ELIBBAD; 822 } /* end elf_fdpic_map_file() */ 823 824 /*****************************************************************************/ 825 /* 826 * map a file with constant displacement under uClinux 827 */ 828 #ifndef CONFIG_MMU 829 static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *params, 830 struct file *file, 831 struct mm_struct *mm) 832 { 833 struct elf32_fdpic_loadseg *seg; 834 struct elf32_phdr *phdr; 835 unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags; 836 loff_t fpos; 837 int loop, ret; 838 839 load_addr = params->load_addr; 840 seg = params->loadmap->segs; 841 842 /* determine the bounds of the contiguous overall allocation we must make */ 843 phdr = params->phdrs; 844 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 845 if (params->phdrs[loop].p_type != PT_LOAD) 846 continue; 847 848 if (base > phdr->p_vaddr) 849 base = phdr->p_vaddr; 850 if (top < phdr->p_vaddr + phdr->p_memsz) 851 top = phdr->p_vaddr + phdr->p_memsz; 852 } 853 854 /* allocate one big anon block for everything */ 855 mflags = MAP_PRIVATE; 856 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE) 857 mflags |= MAP_EXECUTABLE; 858 859 down_write(&mm->mmap_sem); 860 maddr = do_mmap(NULL, load_addr, top - base, 861 PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0); 862 up_write(&mm->mmap_sem); 863 if (IS_ERR((void *) maddr)) 864 return (int) maddr; 865 866 if (load_addr != 0) 867 load_addr += PAGE_ALIGN(top - base); 868 869 /* and then load the file segments into it */ 870 phdr = params->phdrs; 871 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 872 if (params->phdrs[loop].p_type != PT_LOAD) 873 continue; 874 875 fpos = phdr->p_offset; 876 877 seg->addr = maddr + (phdr->p_vaddr - base); 878 seg->p_vaddr = phdr->p_vaddr; 879 seg->p_memsz = phdr->p_memsz; 880 881 ret = file->f_op->read(file, (void *) seg->addr, phdr->p_filesz, &fpos); 882 if (ret < 0) 883 return ret; 884 885 /* map the ELF header address if in this segment */ 886 if (phdr->p_offset == 0) 887 params->elfhdr_addr = seg->addr; 888 889 /* clear any space allocated but not loaded */ 890 if (phdr->p_filesz < phdr->p_memsz) 891 clear_user((void *) (seg->addr + phdr->p_filesz), 892 phdr->p_memsz - phdr->p_filesz); 893 894 if (mm) { 895 if (phdr->p_flags & PF_X) { 896 mm->start_code = seg->addr; 897 mm->end_code = seg->addr + phdr->p_memsz; 898 } 899 else if (!mm->start_data) { 900 mm->start_data = seg->addr; 901 #ifndef CONFIG_MMU 902 mm->end_data = seg->addr + phdr->p_memsz; 903 #endif 904 } 905 906 #ifdef CONFIG_MMU 907 if (seg->addr + phdr->p_memsz > mm->end_data) 908 mm->end_data = seg->addr + phdr->p_memsz; 909 #endif 910 } 911 912 seg++; 913 } 914 915 return 0; 916 } /* end elf_fdpic_map_file_constdisp_on_uclinux() */ 917 #endif 918 919 /*****************************************************************************/ 920 /* 921 * map a binary by direct mmap() of the individual PT_LOAD segments 922 */ 923 static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, 924 struct file *file, 925 struct mm_struct *mm) 926 { 927 struct elf32_fdpic_loadseg *seg; 928 struct elf32_phdr *phdr; 929 unsigned long load_addr, delta_vaddr; 930 int loop, dvset; 931 932 load_addr = params->load_addr; 933 delta_vaddr = 0; 934 dvset = 0; 935 936 seg = params->loadmap->segs; 937 938 /* deal with each load segment separately */ 939 phdr = params->phdrs; 940 for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { 941 unsigned long maddr, disp, excess, excess1; 942 int prot = 0, flags; 943 944 if (phdr->p_type != PT_LOAD) 945 continue; 946 947 kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx", 948 (unsigned long) phdr->p_vaddr, 949 (unsigned long) phdr->p_offset, 950 (unsigned long) phdr->p_filesz, 951 (unsigned long) phdr->p_memsz); 952 953 /* determine the mapping parameters */ 954 if (phdr->p_flags & PF_R) prot |= PROT_READ; 955 if (phdr->p_flags & PF_W) prot |= PROT_WRITE; 956 if (phdr->p_flags & PF_X) prot |= PROT_EXEC; 957 958 flags = MAP_PRIVATE | MAP_DENYWRITE; 959 if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE) 960 flags |= MAP_EXECUTABLE; 961 962 maddr = 0; 963 964 switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) { 965 case ELF_FDPIC_FLAG_INDEPENDENT: 966 /* PT_LOADs are independently locatable */ 967 break; 968 969 case ELF_FDPIC_FLAG_HONOURVADDR: 970 /* the specified virtual address must be honoured */ 971 maddr = phdr->p_vaddr; 972 flags |= MAP_FIXED; 973 break; 974 975 case ELF_FDPIC_FLAG_CONSTDISP: 976 /* constant displacement 977 * - can be mapped anywhere, but must be mapped as a unit 978 */ 979 if (!dvset) { 980 maddr = load_addr; 981 delta_vaddr = phdr->p_vaddr; 982 dvset = 1; 983 } 984 else { 985 maddr = load_addr + phdr->p_vaddr - delta_vaddr; 986 flags |= MAP_FIXED; 987 } 988 break; 989 990 case ELF_FDPIC_FLAG_CONTIGUOUS: 991 /* contiguity handled later */ 992 break; 993 994 default: 995 BUG(); 996 } 997 998 maddr &= PAGE_MASK; 999 1000 /* create the mapping */ 1001 disp = phdr->p_vaddr & ~PAGE_MASK; 1002 down_write(&mm->mmap_sem); 1003 maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags, 1004 phdr->p_offset - disp); 1005 up_write(&mm->mmap_sem); 1006 1007 kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx", 1008 loop, phdr->p_memsz + disp, prot, flags, phdr->p_offset - disp, 1009 maddr); 1010 1011 if (IS_ERR((void *) maddr)) 1012 return (int) maddr; 1013 1014 if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) == ELF_FDPIC_FLAG_CONTIGUOUS) 1015 load_addr += PAGE_ALIGN(phdr->p_memsz + disp); 1016 1017 seg->addr = maddr + disp; 1018 seg->p_vaddr = phdr->p_vaddr; 1019 seg->p_memsz = phdr->p_memsz; 1020 1021 /* map the ELF header address if in this segment */ 1022 if (phdr->p_offset == 0) 1023 params->elfhdr_addr = seg->addr; 1024 1025 /* clear the bit between beginning of mapping and beginning of PT_LOAD */ 1026 if (prot & PROT_WRITE && disp > 0) { 1027 kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp); 1028 clear_user((void __user *) maddr, disp); 1029 maddr += disp; 1030 } 1031 1032 /* clear any space allocated but not loaded 1033 * - on uClinux we can just clear the lot 1034 * - on MMU linux we'll get a SIGBUS beyond the last page 1035 * extant in the file 1036 */ 1037 excess = phdr->p_memsz - phdr->p_filesz; 1038 excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK); 1039 1040 #ifdef CONFIG_MMU 1041 1042 if (excess > excess1) { 1043 unsigned long xaddr = maddr + phdr->p_filesz + excess1; 1044 unsigned long xmaddr; 1045 1046 flags |= MAP_FIXED | MAP_ANONYMOUS; 1047 down_write(&mm->mmap_sem); 1048 xmaddr = do_mmap(NULL, xaddr, excess - excess1, prot, flags, 0); 1049 up_write(&mm->mmap_sem); 1050 1051 kdebug("mmap[%d] <anon>" 1052 " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx", 1053 loop, xaddr, excess - excess1, prot, flags, xmaddr); 1054 1055 if (xmaddr != xaddr) 1056 return -ENOMEM; 1057 } 1058 1059 if (prot & PROT_WRITE && excess1 > 0) { 1060 kdebug("clear[%d] ad=%lx sz=%lx", 1061 loop, maddr + phdr->p_filesz, excess1); 1062 clear_user((void __user *) maddr + phdr->p_filesz, excess1); 1063 } 1064 1065 #else 1066 if (excess > 0) { 1067 kdebug("clear[%d] ad=%lx sz=%lx", 1068 loop, maddr + phdr->p_filesz, excess); 1069 clear_user((void *) maddr + phdr->p_filesz, excess); 1070 } 1071 #endif 1072 1073 if (mm) { 1074 if (phdr->p_flags & PF_X) { 1075 mm->start_code = maddr; 1076 mm->end_code = maddr + phdr->p_memsz; 1077 } 1078 else if (!mm->start_data) { 1079 mm->start_data = maddr; 1080 mm->end_data = maddr + phdr->p_memsz; 1081 } 1082 } 1083 1084 seg++; 1085 } 1086 1087 return 0; 1088 } /* end elf_fdpic_map_file_by_direct_mmap() */ 1089