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);
  35
  36 extern void dump_thread(struct pt_regs *, struct user *);
  37
  38 static struct linux_binfmt aout_format = {
  39 #ifndef MODULE
  40         NULL, NULL, load_aout_binary, load_aout_library, aout_core_dump
  41 #else
  42         NULL, &__this_module, load_aout_binary, load_aout_library, aout_core_dump
  43 #endif
  44 };
  45
  46 static void set_brk(unsigned long start, unsigned long end)
  47 {
  48         start = PAGE_ALIGN(start);
  49         end = PAGE_ALIGN(end);
  50         if (end <= start)
  51                 return;
  52         do_mmap(NULL, start, end - start,
  53                 PROT_READ | PROT_WRITE | PROT_EXEC,
  54                 MAP_FIXED | MAP_PRIVATE, 0);
  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 #define DUMP_WRITE(addr,nr) \
  62 while (file.f_op->write(&file,(char *)(addr),(nr),&file.f_pos) != (nr)) goto close_coredump
  63
  64 #define DUMP_SEEK(offset) \
  65 if (file.f_op->llseek) { \
  66         if (file.f_op->llseek(&file,(offset),0) != (offset)) \
  67                 goto close_coredump; \
  68 } else file.f_pos = (offset)
  69
  70 /*
  71  * Routine writes a core dump image in the current directory.
  72  * Currently only a stub-function.
  73  *
  74  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  75  * changed due to the set[u|g]id. It's enforced by the "current->dumpable"
  76  * field, which also makes sure the core-dumps won't be recursive if the
  77  * dumping of the process results in another error..
  78  */
  79
  80 static inline int
  81 do_aout_core_dump(long signr, struct pt_regs * regs)
  82 {
  83         struct dentry * dentry = NULL;
  84         struct inode * inode = NULL;
  85         struct file file;
  86         mm_segment_t fs;
  87         int has_dumped = 0;
  88         char corefile[6+sizeof(current->comm)];
  89         unsigned long dump_start, dump_size;
  90         struct user dump;
  91 #if defined(__alpha__)
  92 #       define START_DATA(u)    (u.start_data)
  93 #elif defined(__sparc__)
  94 #       define START_DATA(u)    (u.u_tsize)
  95 #elif defined(__i386__) || defined(__mc68000__)
  96 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
  97 #endif
  98 #ifdef __sparc__
  99 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
 100 #else
 101 #       define START_STACK(u)   (u.start_stack)
 102 #endif
 103
 104         if (!current->dumpable || atomic_read(&current->mm->count) != 1)
 105                 return 0;
 106         current->dumpable = 0;
 107
 108 /* See if we have enough room to write the upage.  */
 109         if (current->rlim[RLIMIT_CORE].rlim_cur < PAGE_SIZE)
 110                 return 0;
 111         fs = get_fs();
 112         set_fs(KERNEL_DS);
 113         memcpy(corefile,"core.",5);
 114 #if 0
 115         memcpy(corefile+5,current->comm,sizeof(current->comm));
 116 #else
 117         corefile[4] = '\0';
 118 #endif
 119         dentry = open_namei(corefile,O_CREAT | 2 | O_TRUNC, 0600);
 120         if (IS_ERR(dentry)) {
 121                 dentry = NULL;
 122                 goto end_coredump;
 123         }
 124         inode = dentry->d_inode;
 125         if (!S_ISREG(inode->i_mode))
 126                 goto end_coredump;
 127         if (!inode->i_op || !inode->i_op->default_file_ops)
 128                 goto end_coredump;
 129         if (get_write_access(inode))
 130                 goto end_coredump;
 131         if (init_private_file(&file, dentry, 3))
 132                 goto end_coredump_write;
 133         if (!file.f_op->write)
 134                 goto close_coredump;
 135         has_dumped = 1;
 136         current->flags |= PF_DUMPCORE;
 137         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 138 #ifndef __sparc__
 139         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 140 #endif
 141         dump.signal = signr;
 142         dump_thread(regs, &dump);
 143
 144 /* If the size of the dump file exceeds the rlimit, then see what would happen
 145    if we wrote the stack, but not the data area.  */
 146 #ifdef __sparc__
 147         if ((dump.u_dsize+dump.u_ssize) >
 148             current->rlim[RLIMIT_CORE].rlim_cur)
 149                 dump.u_dsize = 0;
 150 #else
 151         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 152             current->rlim[RLIMIT_CORE].rlim_cur)
 153                 dump.u_dsize = 0;
 154 #endif
 155
 156 /* Make sure we have enough room to write the stack and data areas. */
 157 #ifdef __sparc__
 158         if ((dump.u_ssize) >
 159             current->rlim[RLIMIT_CORE].rlim_cur)
 160                 dump.u_ssize = 0;
 161 #else
 162         if ((dump.u_ssize+1) * PAGE_SIZE >
 163             current->rlim[RLIMIT_CORE].rlim_cur)
 164                 dump.u_ssize = 0;
 165 #endif
 166
 167 /* make sure we actually have a data and stack area to dump */
 168         set_fs(USER_DS);
 169 #ifdef __sparc__
 170         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 171                 dump.u_dsize = 0;
 172         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 173                 dump.u_ssize = 0;
 174 #else
 175         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 176                 dump.u_dsize = 0;
 177         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 178                 dump.u_ssize = 0;
 179 #endif
 180
 181         set_fs(KERNEL_DS);
 182 /* struct user */
 183         DUMP_WRITE(&dump,sizeof(dump));
 184 /* Now dump all of the user data.  Include malloced stuff as well */
 185 #ifndef __sparc__
 186         DUMP_SEEK(PAGE_SIZE);
 187 #endif
 188 /* now we start writing out the user space info */
 189         set_fs(USER_DS);
 190 /* Dump the data area */
 191         if (dump.u_dsize != 0) {
 192                 dump_start = START_DATA(dump);
 193 #ifdef __sparc__
 194                 dump_size = dump.u_dsize;
 195 #else
 196                 dump_size = dump.u_dsize << PAGE_SHIFT;
 197 #endif
 198                 DUMP_WRITE(dump_start,dump_size);
 199         }
 200 /* Now prepare to dump the stack area */
 201         if (dump.u_ssize != 0) {
 202                 dump_start = START_STACK(dump);
 203 #ifdef __sparc__
 204                 dump_size = dump.u_ssize;
 205 #else
 206                 dump_size = dump.u_ssize << PAGE_SHIFT;
 207 #endif
 208                 DUMP_WRITE(dump_start,dump_size);
 209         }
 210 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 211         set_fs(KERNEL_DS);
 212         DUMP_WRITE(current,sizeof(*current));
 213 close_coredump:
 214         if (file.f_op->release)
 215                 file.f_op->release(inode,&file);
 216 end_coredump_write:
 217         put_write_access(inode);
 218 end_coredump:
 219         set_fs(fs);
 220         dput(dentry);
 221         return has_dumped;
 222 }
 223
 224 static int
 225 aout_core_dump(long signr, struct pt_regs * regs)
 226 {
 227         int retval;
 228
 229         MOD_INC_USE_COUNT;
 230         retval = do_aout_core_dump(signr, regs);
 231         MOD_DEC_USE_COUNT;
 232         return retval;
 233 }
 234
 235 /*
 236  * create_aout_tables() parses the env- and arg-strings in new user
 237  * memory and creates the pointer tables from them, and puts their
 238  * addresses on the "stack", returning the new stack pointer value.
 239  */
 240 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 241 {
 242         char **argv, **envp;
 243         unsigned long * sp;
 244         int argc = bprm->argc;
 245         int envc = bprm->envc;
 246
 247         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 248 #ifdef __sparc__
 249         /* This imposes the proper stack alignment for a new process. */
 250         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 251         if ((envc+argc+3)&1) --sp;
 252 #endif
 253 #ifdef __alpha__
 254 /* whee.. test-programs are so much fun. */
 255         put_user(0, --sp);
 256         put_user(0, --sp);
 257         if (bprm->loader) {
 258                 put_user(0, --sp);
 259                 put_user(0x3eb, --sp);
 260                 put_user(bprm->loader, --sp);
 261                 put_user(0x3ea, --sp);
 262         }
 263         put_user(bprm->exec, --sp);
 264         put_user(0x3e9, --sp);
 265 #endif
 266         sp -= envc+1;
 267         envp = (char **) sp;
 268         sp -= argc+1;
 269         argv = (char **) sp;
 270 #if defined(__i386__) || defined(__mc68000__)
 271         put_user((unsigned long) envp,--sp);
 272         put_user((unsigned long) argv,--sp);
 273 #endif
 274         put_user(argc,--sp);
 275         current->mm->arg_start = (unsigned long) p;
 276         while (argc-->0) {
 277                 char c;
 278                 put_user(p,argv++);
 279                 do {
 280                         get_user(c,p++);
 281                 } while (c);
 282         }
 283         put_user(NULL,argv);
 284         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 285         while (envc-->0) {
 286                 char c;
 287                 put_user(p,envp++);
 288                 do {
 289                         get_user(c,p++);
 290                 } while (c);
 291         }
 292         put_user(NULL,envp);
 293         current->mm->env_end = (unsigned long) p;
 294         return sp;
 295 }
 296
 297 /*
 298  * These are the functions used to load a.out style executables and shared
 299  * libraries.  There is no binary dependent code anywhere else.
 300  */
 301
 302 static inline int do_load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 303 {
 304         struct exec ex;
 305         struct file * file;
 306         int fd;
 307         unsigned long error;
 308         unsigned long p = bprm->p;
 309         unsigned long fd_offset;
 310         unsigned long rlim;
 311         int retval;
 312
 313         ex = *((struct exec *) bprm->buf);              /* exec-header */
 314         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 315              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 316             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 317             bprm->dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 318                 return -ENOEXEC;
 319         }
 320
 321         current->personality = PER_LINUX;
 322         fd_offset = N_TXTOFF(ex);
 323
 324 #ifdef __i386__
 325         if (N_MAGIC(ex) == ZMAGIC && fd_offset != BLOCK_SIZE) {
 326                 printk(KERN_NOTICE "N_TXTOFF != BLOCK_SIZE. See a.out.h.\n");
 327                 return -ENOEXEC;
 328         }
 329
 330         if (N_MAGIC(ex) == ZMAGIC && ex.a_text &&
 331             (fd_offset < bprm->dentry->d_inode->i_sb->s_blocksize)) {
 332                 printk(KERN_NOTICE "N_TXTOFF < BLOCK_SIZE. Please convert binary.\n");
 333                 return -ENOEXEC;
 334         }
 335 #endif
 336
 337         /* Check initial limits. This avoids letting people circumvent
 338          * size limits imposed on them by creating programs with large
 339          * arrays in the data or bss.
 340          */
 341         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 342         if (rlim >= RLIM_INFINITY)
 343                 rlim = ~0;
 344         if (ex.a_data + ex.a_bss > rlim)
 345                 return -ENOMEM;
 346
 347         /* Flush all traces of the currently running executable */
 348         retval = flush_old_exec(bprm);
 349         if (retval)
 350                 return retval;
 351
 352         /* OK, This is the point of no return */
 353 #if defined(__sparc__) && !defined(__sparc_v9__)
 354         memcpy(&current->tss.core_exec, &ex, sizeof(struct exec));
 355 #endif
 356
 357         current->mm->end_code = ex.a_text +
 358                 (current->mm->start_code = N_TXTADDR(ex));
 359         current->mm->end_data = ex.a_data +
 360                 (current->mm->start_data = N_DATADDR(ex));
 361         current->mm->brk = ex.a_bss +
 362                 (current->mm->start_brk = N_BSSADDR(ex));
 363
 364         current->mm->rss = 0;
 365         current->mm->mmap = NULL;
 366         compute_creds(bprm);
 367         current->flags &= ~PF_FORKNOEXEC;
 368 #ifdef __sparc__
 369         if (N_MAGIC(ex) == NMAGIC) {
 370                 /* Fuck me plenty... */
 371                 error = do_mmap(NULL, N_TXTADDR(ex), ex.a_text,
 372                                 PROT_READ|PROT_WRITE|PROT_EXEC,
 373                                 MAP_FIXED|MAP_PRIVATE, 0);
 374                 read_exec(bprm->dentry, fd_offset, (char *) N_TXTADDR(ex),
 375                           ex.a_text, 0);
 376                 error = do_mmap(NULL, N_DATADDR(ex), ex.a_data,
 377                                 PROT_READ|PROT_WRITE|PROT_EXEC,
 378                                 MAP_FIXED|MAP_PRIVATE, 0);
 379                 read_exec(bprm->dentry, fd_offset + ex.a_text, (char *) N_DATADDR(ex),
 380                           ex.a_data, 0);
 381                 goto beyond_if;
 382         }
 383 #endif
 384
 385         if (N_MAGIC(ex) == OMAGIC) {
 386 #if defined(__alpha__) || defined(__sparc__)
 387                 do_mmap(NULL, N_TXTADDR(ex) & PAGE_MASK,
 388                         ex.a_text+ex.a_data + PAGE_SIZE - 1,
 389                         PROT_READ|PROT_WRITE|PROT_EXEC,
 390                         MAP_FIXED|MAP_PRIVATE, 0);
 391                 read_exec(bprm->dentry, fd_offset, (char *) N_TXTADDR(ex),
 392                           ex.a_text+ex.a_data, 0);
 393 #else
 394                 do_mmap(NULL, 0, ex.a_text+ex.a_data,
 395                         PROT_READ|PROT_WRITE|PROT_EXEC,
 396                         MAP_FIXED|MAP_PRIVATE, 0);
 397                 read_exec(bprm->dentry, 32, (char *) 0, ex.a_text+ex.a_data, 0);
 398 #endif
 399         } else {
 400                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 401                     (N_MAGIC(ex) != NMAGIC))
 402                         printk(KERN_NOTICE "executable not page aligned\n");
 403
 404                 fd = open_dentry(bprm->dentry, O_RDONLY);
 405                 if (fd < 0)
 406                         return fd;
 407                 file = fcheck(fd);
 408
 409                 if (!file->f_op || !file->f_op->mmap) {
 410                         sys_close(fd);
 411                         do_mmap(NULL, 0, ex.a_text+ex.a_data,
 412                                 PROT_READ|PROT_WRITE|PROT_EXEC,
 413                                 MAP_FIXED|MAP_PRIVATE, 0);
 414                         read_exec(bprm->dentry, fd_offset,
 415                                   (char *) N_TXTADDR(ex), ex.a_text+ex.a_data, 0);
 416                         goto beyond_if;
 417                 }
 418
 419                 error = do_mmap(file, N_TXTADDR(ex), ex.a_text,
 420                         PROT_READ | PROT_EXEC,
 421                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 422                         fd_offset);
 423
 424                 if (error != N_TXTADDR(ex)) {
 425                         sys_close(fd);
 426                         send_sig(SIGKILL, current, 0);
 427                         return error;
 428                 }
 429
 430                 error = do_mmap(file, N_DATADDR(ex), ex.a_data,
 431                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 432                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 433                                 fd_offset + ex.a_text);
 434                 sys_close(fd);
 435                 if (error != N_DATADDR(ex)) {
 436                         send_sig(SIGKILL, current, 0);
 437                         return error;
 438                 }
 439         }
 440 beyond_if:
 441         if (current->exec_domain && current->exec_domain->module)
 442                 __MOD_DEC_USE_COUNT(current->exec_domain->module);
 443         if (current->binfmt && current->binfmt->module)
 444                 __MOD_DEC_USE_COUNT(current->binfmt->module);
 445         current->exec_domain = lookup_exec_domain(current->personality);
 446         current->binfmt = &aout_format;
 447         if (current->exec_domain && current->exec_domain->module)
 448                 __MOD_INC_USE_COUNT(current->exec_domain->module);
 449         if (current->binfmt && current->binfmt->module)
 450                 __MOD_INC_USE_COUNT(current->binfmt->module);
 451
 452         set_brk(current->mm->start_brk, current->mm->brk);
 453
 454         p = setup_arg_pages(p, bprm);
 455
 456         p = (unsigned long) create_aout_tables((char *)p, bprm);
 457         current->mm->start_stack = p;
 458 #ifdef __alpha__
 459         regs->gp = ex.a_gpvalue;
 460 #endif
 461         start_thread(regs, ex.a_entry, p);
 462         if (current->flags & PF_PTRACED)
 463                 send_sig(SIGTRAP, current, 0);
 464         return 0;
 465 }
 466
 467
 468 static int
 469 load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 470 {
 471         int retval;
 472
 473         MOD_INC_USE_COUNT;
 474         retval = do_load_aout_binary(bprm, regs);
 475         MOD_DEC_USE_COUNT;
 476         return retval;
 477 }
 478
 479 static inline int
 480 do_load_aout_library(int fd)
 481 {
 482         struct file * file;
 483         struct inode * inode;
 484         unsigned long bss, start_addr, len;
 485         unsigned long error;
 486         int retval;
 487         loff_t offset = 0;
 488         struct exec ex;
 489
 490         retval = -EACCES;
 491         file = fget(fd);
 492         if (!file)
 493                 goto out;
 494         if (!file->f_op)
 495                 goto out_putf;
 496         inode = file->f_dentry->d_inode;
 497
 498         retval = -ENOEXEC;
 499         /* N.B. Save current fs? */
 500         set_fs(KERNEL_DS);
 501         error = file->f_op->read(file, (char *) &ex, sizeof(ex), &offset);
 502         set_fs(USER_DS);
 503         if (error != sizeof(ex))
 504                 goto out_putf;
 505
 506         /* We come in here for the regular a.out style of shared libraries */
 507         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 508             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 509             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 510                 goto out_putf;
 511         }
 512
 513         if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
 514             (N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
 515                 printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
 516                 goto out_putf;
 517         }
 518
 519         if (N_FLAGS(ex))
 520                 goto out_putf;
 521
 522         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 523            this off to get the starting address for the page */
 524
 525         start_addr =  ex.a_entry & 0xfffff000;
 526
 527         /* Now use mmap to map the library into memory. */
 528         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 529                         PROT_READ | PROT_WRITE | PROT_EXEC,
 530                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 531                         N_TXTOFF(ex));
 532         retval = error;
 533         if (error != start_addr)
 534                 goto out_putf;
 535
 536         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 537         bss = ex.a_text + ex.a_data + ex.a_bss;
 538         if (bss > len) {
 539                 error = do_mmap(NULL, start_addr + len, bss - len,
 540                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 541                                 MAP_PRIVATE | MAP_FIXED, 0);
 542                 retval = error;
 543                 if (error != start_addr + len)
 544                         goto out_putf;
 545         }
 546         retval = 0;
 547
 548 out_putf:
 549         fput(file);
 550 out:
 551         return retval;
 552 }
 553
 554 static int
 555 load_aout_library(int fd)
 556 {
 557         int retval;
 558
 559         MOD_INC_USE_COUNT;
 560         retval = do_load_aout_library(fd);
 561         MOD_DEC_USE_COUNT;
 562         return retval;
 563 }
 564
 565
 566 __initfunc(int init_aout_binfmt(void))
 567 {
 568         return register_binfmt(&aout_format);
 569 }
 570
 571 #ifdef MODULE
 572 int init_module(void) {
 573         return init_aout_binfmt();
 574 }
 575
 576 void cleanup_module( void) {
 577         unregister_binfmt(&aout_format);
 578 }
 579 #endif