fs/binfmt_aout.c

   1 /*
   2  *  linux/fs/binfmt_aout.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
   5  */
   6
   7 #include <linux/module.h>
   8
   9 #include <linux/sched.h>
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/mman.h>
  13 #include <linux/a.out.h>
  14 #include <linux/errno.h>
  15 #include <linux/signal.h>
  16 #include <linux/string.h>
  17 #include <linux/fs.h>
  18 #include <linux/file.h>
  19 #include <linux/stat.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/user.h>
  23 #include <linux/malloc.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/personality.h>
  26 #include <linux/init.h>
  27
  28 #include <asm/system.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31
  32 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  33 static int load_aout_library(int fd);
  34 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
  35
  36 extern void dump_thread(struct pt_regs *, struct user *);
  37
  38 static struct linux_binfmt aout_format = {
  39         NULL,
  40 #ifndef MODULE
  41         NULL,
  42 #else
  43         &__this_module,
  44 #endif
  45         load_aout_binary, load_aout_library, aout_core_dump, PAGE_SIZE
  46 };
  47
  48 static void set_brk(unsigned long start, unsigned long end)
  49 {
  50         start = PAGE_ALIGN(start);
  51         end = PAGE_ALIGN(end);
  52         if (end <= start)
  53                 return;
  54         do_brk(start, end - start);
  55 }
  56
  57 /*
  58  * These are the only things you should do on a core-file: use only these
  59  * macros to write out all the necessary info.
  60  */
  61
  62 static int dump_write(struct file *file, const void *addr, int nr)
  63 {
  64         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  65 }
  66
  67 #define DUMP_WRITE(addr, nr)    \
  68         if (!dump_write(file, (void *)(addr), (nr))) \
  69                 goto end_coredump;
  70
  71 #define DUMP_SEEK(offset) \
  72 if (file->f_op->llseek) { \
  73         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  74                 goto end_coredump; \
  75 } else file->f_pos = (offset)
  76
  77 /*
  78  * Routine writes a core dump image in the current directory.
  79  * Currently only a stub-function.
  80  *
  81  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  82  * changed due to the set[u|g]id. It's enforced by the "current->dumpable"
  83  * field, which also makes sure the core-dumps won't be recursive if the
  84  * dumping of the process results in another error..
  85  */
  86
  87 static inline int
  88 do_aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
  89 {
  90         mm_segment_t fs;
  91         int has_dumped = 0;
  92         unsigned long dump_start, dump_size;
  93         struct user dump;
  94 #if defined(__alpha__)
  95 #       define START_DATA(u)    (u.start_data)
  96 #elif defined(__sparc__)
  97 #       define START_DATA(u)    (u.u_tsize)
  98 #elif defined(__i386__) || defined(__mc68000__)
  99 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 100 #endif
 101 #ifdef __sparc__
 102 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
 103 #else
 104 #       define START_STACK(u)   (u.start_stack)
 105 #endif
 106
 107         fs = get_fs();
 108         set_fs(KERNEL_DS);
 109         has_dumped = 1;
 110         current->flags |= PF_DUMPCORE;
 111         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 112 #ifndef __sparc__
 113         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 114 #endif
 115         dump.signal = signr;
 116         dump_thread(regs, &dump);
 117
 118 /* If the size of the dump file exceeds the rlimit, then see what would happen
 119    if we wrote the stack, but not the data area.  */
 120 #ifdef __sparc__
 121         if ((dump.u_dsize+dump.u_ssize) >
 122             current->rlim[RLIMIT_CORE].rlim_cur)
 123                 dump.u_dsize = 0;
 124 #else
 125         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 126             current->rlim[RLIMIT_CORE].rlim_cur)
 127                 dump.u_dsize = 0;
 128 #endif
 129
 130 /* Make sure we have enough room to write the stack and data areas. */
 131 #ifdef __sparc__
 132         if ((dump.u_ssize) >
 133             current->rlim[RLIMIT_CORE].rlim_cur)
 134                 dump.u_ssize = 0;
 135 #else
 136         if ((dump.u_ssize+1) * PAGE_SIZE >
 137             current->rlim[RLIMIT_CORE].rlim_cur)
 138                 dump.u_ssize = 0;
 139 #endif
 140
 141 /* make sure we actually have a data and stack area to dump */
 142         set_fs(USER_DS);
 143 #ifdef __sparc__
 144         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 145                 dump.u_dsize = 0;
 146         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 147                 dump.u_ssize = 0;
 148 #else
 149         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 150                 dump.u_dsize = 0;
 151         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 152                 dump.u_ssize = 0;
 153 #endif
 154
 155         set_fs(KERNEL_DS);
 156 /* struct user */
 157         DUMP_WRITE(&dump,sizeof(dump));
 158 /* Now dump all of the user data.  Include malloced stuff as well */
 159 #ifndef __sparc__
 160         DUMP_SEEK(PAGE_SIZE);
 161 #endif
 162 /* now we start writing out the user space info */
 163         set_fs(USER_DS);
 164 /* Dump the data area */
 165         if (dump.u_dsize != 0) {
 166                 dump_start = START_DATA(dump);
 167 #ifdef __sparc__
 168                 dump_size = dump.u_dsize;
 169 #else
 170                 dump_size = dump.u_dsize << PAGE_SHIFT;
 171 #endif
 172                 DUMP_WRITE(dump_start,dump_size);
 173         }
 174 /* Now prepare to dump the stack area */
 175         if (dump.u_ssize != 0) {
 176                 dump_start = START_STACK(dump);
 177 #ifdef __sparc__
 178                 dump_size = dump.u_ssize;
 179 #else
 180                 dump_size = dump.u_ssize << PAGE_SHIFT;
 181 #endif
 182                 DUMP_WRITE(dump_start,dump_size);
 183         }
 184 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 185         set_fs(KERNEL_DS);
 186         DUMP_WRITE(current,sizeof(*current));
 187 end_coredump:
 188         set_fs(fs);
 189         return has_dumped;
 190 }
 191
 192 static int
 193 aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
 194 {
 195         int retval;
 196
 197         MOD_INC_USE_COUNT;
 198         retval = do_aout_core_dump(signr, regs, file);
 199         MOD_DEC_USE_COUNT;
 200         return retval;
 201 }
 202
 203 /*
 204  * create_aout_tables() parses the env- and arg-strings in new user
 205  * memory and creates the pointer tables from them, and puts their
 206  * addresses on the "stack", returning the new stack pointer value.
 207  */
 208 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 209 {
 210         char **argv, **envp;
 211         unsigned long * sp;
 212         int argc = bprm->argc;
 213         int envc = bprm->envc;
 214
 215         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 216 #ifdef __sparc__
 217         /* This imposes the proper stack alignment for a new process. */
 218         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 219         if ((envc+argc+3)&1) --sp;
 220 #endif
 221 #ifdef __alpha__
 222 /* whee.. test-programs are so much fun. */
 223         put_user(0, --sp);
 224         put_user(0, --sp);
 225         if (bprm->loader) {
 226                 put_user(0, --sp);
 227                 put_user(0x3eb, --sp);
 228                 put_user(bprm->loader, --sp);
 229                 put_user(0x3ea, --sp);
 230         }
 231         put_user(bprm->exec, --sp);
 232         put_user(0x3e9, --sp);
 233 #endif
 234         sp -= envc+1;
 235         envp = (char **) sp;
 236         sp -= argc+1;
 237         argv = (char **) sp;
 238 #if defined(__i386__) || defined(__mc68000__)
 239         put_user((unsigned long) envp,--sp);
 240         put_user((unsigned long) argv,--sp);
 241 #endif
 242         put_user(argc,--sp);
 243         current->mm->arg_start = (unsigned long) p;
 244         while (argc-->0) {
 245                 char c;
 246                 put_user(p,argv++);
 247                 do {
 248                         get_user(c,p++);
 249                 } while (c);
 250         }
 251         put_user(NULL,argv);
 252         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 253         while (envc-->0) {
 254                 char c;
 255                 put_user(p,envp++);
 256                 do {
 257                         get_user(c,p++);
 258                 } while (c);
 259         }
 260         put_user(NULL,envp);
 261         current->mm->env_end = (unsigned long) p;
 262         return sp;
 263 }
 264
 265 /*
 266  * These are the functions used to load a.out style executables and shared
 267  * libraries.  There is no binary dependent code anywhere else.
 268  */
 269
 270 static inline int do_load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 271 {
 272         struct exec ex;
 273         struct file * file;
 274         int fd;
 275         unsigned long error;
 276         unsigned long fd_offset;
 277         unsigned long rlim;
 278         int retval;
 279
 280         ex = *((struct exec *) bprm->buf);              /* exec-header */
 281         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 282              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 283             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 284             bprm->dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 285                 return -ENOEXEC;
 286         }
 287
 288         fd_offset = N_TXTOFF(ex);
 289
 290 #ifdef __i386__
 291         if (N_MAGIC(ex) == ZMAGIC && fd_offset != BLOCK_SIZE) {
 292                 printk(KERN_NOTICE "N_TXTOFF != BLOCK_SIZE. See a.out.h.\n");
 293                 return -ENOEXEC;
 294         }
 295
 296         if (N_MAGIC(ex) == ZMAGIC && ex.a_text &&
 297             bprm->dentry->d_inode->i_op &&
 298             bprm->dentry->d_inode->i_op->get_block &&
 299             (fd_offset < bprm->dentry->d_inode->i_sb->s_blocksize)) {
 300                 printk(KERN_NOTICE "N_TXTOFF < BLOCK_SIZE. Please convert binary.\n");
 301                 return -ENOEXEC;
 302         }
 303 #endif
 304
 305         /* Check initial limits. This avoids letting people circumvent
 306          * size limits imposed on them by creating programs with large
 307          * arrays in the data or bss.
 308          */
 309         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 310         if (rlim >= RLIM_INFINITY)
 311                 rlim = ~0;
 312         if (ex.a_data + ex.a_bss > rlim)
 313                 return -ENOMEM;
 314
 315         /* Flush all traces of the currently running executable */
 316         retval = flush_old_exec(bprm);
 317         if (retval)
 318                 return retval;
 319
 320         /* OK, This is the point of no return */
 321         current->personality = PER_LINUX;
 322
 323 #if defined(__sparc__) && !defined(__sparc_v9__)
 324         memcpy(&current->tss.core_exec, &ex, sizeof(struct exec));
 325 #endif
 326
 327         current->mm->end_code = ex.a_text +
 328                 (current->mm->start_code = N_TXTADDR(ex));
 329         current->mm->end_data = ex.a_data +
 330                 (current->mm->start_data = N_DATADDR(ex));
 331         current->mm->brk = ex.a_bss +
 332                 (current->mm->start_brk = N_BSSADDR(ex));
 333
 334         current->mm->rss = 0;
 335         current->mm->mmap = NULL;
 336         compute_creds(bprm);
 337         current->flags &= ~PF_FORKNOEXEC;
 338 #ifdef __sparc__
 339         if (N_MAGIC(ex) == NMAGIC) {
 340                 /* Fuck me plenty... */
 341                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 342                 read_exec(bprm->dentry, fd_offset, (char *) N_TXTADDR(ex),
 343                           ex.a_text, 0);
 344                 error = do_brk(N_DATADDR(ex), ex.a_data);
 345                 read_exec(bprm->dentry, fd_offset + ex.a_text, (char *) N_DATADDR(ex),
 346                           ex.a_data, 0);
 347                 goto beyond_if;
 348         }
 349 #endif
 350
 351         if (N_MAGIC(ex) == OMAGIC) {
 352 #if defined(__alpha__) || defined(__sparc__)
 353                 do_brk(N_TXTADDR(ex) & PAGE_MASK,
 354                         ex.a_text+ex.a_data + PAGE_SIZE - 1);
 355                 read_exec(bprm->dentry, fd_offset, (char *) N_TXTADDR(ex),
 356                           ex.a_text+ex.a_data, 0);
 357 #else
 358                 do_brk(0, ex.a_text+ex.a_data);
 359                 read_exec(bprm->dentry, 32, (char *) 0, ex.a_text+ex.a_data, 0);
 360 #endif
 361                 flush_icache_range((unsigned long) 0,
 362                                    (unsigned long) ex.a_text+ex.a_data);
 363         } else {
 364                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 365                     (N_MAGIC(ex) != NMAGIC))
 366                         printk(KERN_NOTICE "executable not page aligned\n");
 367
 368                 fd = open_dentry(bprm->dentry, O_RDONLY);
 369                 if (fd < 0)
 370                         return fd;
 371                 file = fget(fd);
 372
 373                 if ((fd_offset & ~PAGE_MASK) != 0) {
 374                         printk(KERN_WARNING
 375                                "fd_offset is not page aligned. Please convert program: %s\n",
 376                                file->f_dentry->d_name.name
 377                                );
 378                 }
 379
 380                 if (!file->f_op || !file->f_op->mmap || ((fd_offset & ~PAGE_MASK) != 0)) {
 381                         fput(file);
 382                         sys_close(fd);
 383                         do_brk(0, ex.a_text+ex.a_data);
 384                         read_exec(bprm->dentry, fd_offset,
 385                                   (char *) N_TXTADDR(ex), ex.a_text+ex.a_data, 0);
 386                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 387                                            (unsigned long) N_TXTADDR(ex) +
 388                                            ex.a_text+ex.a_data);
 389                         goto beyond_if;
 390                 }
 391
 392                 error = do_mmap(file, N_TXTADDR(ex), ex.a_text,
 393                         PROT_READ | PROT_EXEC,
 394                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 395                         fd_offset);
 396
 397                 if (error != N_TXTADDR(ex)) {
 398                         fput(file);
 399                         sys_close(fd);
 400                         send_sig(SIGKILL, current, 0);
 401                         return error;
 402                 }
 403
 404                 error = do_mmap(file, N_DATADDR(ex), ex.a_data,
 405                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 406                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 407                                 fd_offset + ex.a_text);
 408                 fput(file);
 409                 sys_close(fd);
 410                 if (error != N_DATADDR(ex)) {
 411                         send_sig(SIGKILL, current, 0);
 412                         return error;
 413                 }
 414         }
 415 beyond_if:
 416         if (current->exec_domain && current->exec_domain->module)
 417                 __MOD_DEC_USE_COUNT(current->exec_domain->module);
 418         if (current->binfmt && current->binfmt->module)
 419                 __MOD_DEC_USE_COUNT(current->binfmt->module);
 420         current->exec_domain = lookup_exec_domain(current->personality);
 421         current->binfmt = &aout_format;
 422         if (current->exec_domain && current->exec_domain->module)
 423                 __MOD_INC_USE_COUNT(current->exec_domain->module);
 424         if (current->binfmt && current->binfmt->module)
 425                 __MOD_INC_USE_COUNT(current->binfmt->module);
 426
 427         set_brk(current->mm->start_brk, current->mm->brk);
 428
 429         retval = setup_arg_pages(bprm);
 430         if (retval < 0) {
 431                 /* Someone check-me: is this error path enough? */
 432                 send_sig(SIGKILL, current, 0);
 433                 return retval;
 434         }
 435
 436         current->mm->start_stack =
 437                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 438 #ifdef __alpha__
 439         regs->gp = ex.a_gpvalue;
 440 #endif
 441         start_thread(regs, ex.a_entry, current->mm->start_stack);
 442         if (current->flags & PF_PTRACED)
 443                 send_sig(SIGTRAP, current, 0);
 444         return 0;
 445 }
 446
 447
 448 static int
 449 load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 450 {
 451         int retval;
 452
 453         MOD_INC_USE_COUNT;
 454         retval = do_load_aout_binary(bprm, regs);
 455         MOD_DEC_USE_COUNT;
 456         return retval;
 457 }
 458
 459 static inline int
 460 do_load_aout_library(int fd)
 461 {
 462         struct file * file;
 463         struct inode * inode;
 464         unsigned long bss, start_addr, len;
 465         unsigned long error;
 466         int retval;
 467         loff_t offset = 0;
 468         struct exec ex;
 469
 470         retval = -EACCES;
 471         file = fget(fd);
 472         if (!file)
 473                 goto out;
 474         if (!file->f_op)
 475                 goto out_putf;
 476         inode = file->f_dentry->d_inode;
 477
 478         retval = -ENOEXEC;
 479         /* N.B. Save current fs? */
 480         set_fs(KERNEL_DS);
 481         error = file->f_op->read(file, (char *) &ex, sizeof(ex), &offset);
 482         set_fs(USER_DS);
 483         if (error != sizeof(ex))
 484                 goto out_putf;
 485
 486         /* We come in here for the regular a.out style of shared libraries */
 487         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 488             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 489             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 490                 goto out_putf;
 491         }
 492
 493         if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
 494             (N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
 495                 printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
 496                 goto out_putf;
 497         }
 498
 499         if (N_FLAGS(ex))
 500                 goto out_putf;
 501
 502         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 503            this off to get the starting address for the page */
 504
 505         start_addr =  ex.a_entry & 0xfffff000;
 506
 507         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 508                 printk(KERN_WARNING
 509                        "N_TXTOFF is not page aligned. Please convert library: %s\n",
 510                        file->f_dentry->d_name.name
 511                        );
 512
 513                 do_mmap(NULL, start_addr & PAGE_MASK, ex.a_text + ex.a_data + ex.a_bss,
 514                         PROT_READ | PROT_WRITE | PROT_EXEC,
 515                         MAP_FIXED| MAP_PRIVATE, 0);
 516
 517                 read_exec(file->f_dentry, N_TXTOFF(ex),
 518                           (char *)start_addr, ex.a_text + ex.a_data, 0);
 519                 flush_icache_range((unsigned long) start_addr,
 520                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 521
 522                 retval = 0;
 523                 goto out_putf;
 524         }
 525         /* Now use mmap to map the library into memory. */
 526         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 527                         PROT_READ | PROT_WRITE | PROT_EXEC,
 528                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 529                         N_TXTOFF(ex));
 530         retval = error;
 531         if (error != start_addr)
 532                 goto out_putf;
 533
 534         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 535         bss = ex.a_text + ex.a_data + ex.a_bss;
 536         if (bss > len) {
 537                 error = do_brk(start_addr + len, bss - len);
 538                 retval = error;
 539                 if (error != start_addr + len)
 540                         goto out_putf;
 541         }
 542         retval = 0;
 543
 544 out_putf:
 545         fput(file);
 546 out:
 547         return retval;
 548 }
 549
 550 static int
 551 load_aout_library(int fd)
 552 {
 553         int retval;
 554
 555         MOD_INC_USE_COUNT;
 556         retval = do_load_aout_library(fd);
 557         MOD_DEC_USE_COUNT;
 558         return retval;
 559 }
 560
 561
 562 int __init init_aout_binfmt(void)
 563 {
 564         return register_binfmt(&aout_format);
 565 }
 566
 567 #ifdef MODULE
 568 int init_module(void) {
 569         return init_aout_binfmt();
 570 }
 571
 572 void cleanup_module( void) {
 573         unregister_binfmt(&aout_format);
 574 }
 575 #endif