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
  62 static int dump_write(struct file *file, const void *addr, int nr)
  63 {
  64         int r;
  65         down(&file->f_dentry->d_inode->i_sem);
  66         r = file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  67         up(&file->f_dentry->d_inode->i_sem);
  68         return r;
  69 }
  70
  71 #define DUMP_WRITE(addr, nr)    \
  72         if (!dump_write(file, (void *)(addr), (nr))) \
  73                 goto close_coredump;
  74
  75 #define DUMP_SEEK(offset) \
  76 if (file->f_op->llseek) { \
  77         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  78                 goto close_coredump; \
  79 } else file->f_pos = (offset)
  80
  81 /*
  82  * Routine writes a core dump image in the current directory.
  83  * Currently only a stub-function.
  84  *
  85  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  86  * changed due to the set[u|g]id. It's enforced by the "current->dumpable"
  87  * field, which also makes sure the core-dumps won't be recursive if the
  88  * dumping of the process results in another error..
  89  */
  90
  91 static inline int
  92 do_aout_core_dump(long signr, struct pt_regs * regs)
  93 {
  94         struct dentry * dentry = NULL;
  95         struct inode * inode = NULL;
  96         struct file * file;
  97         mm_segment_t fs;
  98         int has_dumped = 0;
  99         char corefile[6+sizeof(current->comm)];
 100         unsigned long dump_start, dump_size;
 101         struct user dump;
 102 #if defined(__alpha__)
 103 #       define START_DATA(u)    (u.start_data)
 104 #elif defined(__sparc__)
 105 #       define START_DATA(u)    (u.u_tsize)
 106 #elif defined(__i386__) || defined(__mc68000__)
 107 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 108 #endif
 109 #ifdef __sparc__
 110 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
 111 #else
 112 #       define START_STACK(u)   (u.start_stack)
 113 #endif
 114
 115         if (!current->dumpable || atomic_read(&current->mm->count) != 1)
 116                 return 0;
 117         current->dumpable = 0;
 118
 119 /* See if we have enough room to write the upage.  */
 120         if (current->rlim[RLIMIT_CORE].rlim_cur < PAGE_SIZE)
 121                 return 0;
 122         fs = get_fs();
 123         set_fs(KERNEL_DS);
 124         memcpy(corefile,"core.",5);
 125 #if 0
 126         memcpy(corefile+5,current->comm,sizeof(current->comm));
 127 #else
 128         corefile[4] = '\0';
 129 #endif
 130         file = filp_open(corefile,O_CREAT | 2 | O_TRUNC | O_NOFOLLOW, 0600);
 131         if (IS_ERR(file))
 132                 goto end_coredump;
 133         dentry = file->f_dentry;
 134         inode = dentry->d_inode;
 135         if (!S_ISREG(inode->i_mode))
 136                 goto close_coredump;
 137         if (!inode->i_op || !inode->i_op->default_file_ops)
 138                 goto close_coredump;
 139         if (!file->f_op->write)
 140                 goto close_coredump;
 141         has_dumped = 1;
 142         current->flags |= PF_DUMPCORE;
 143         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 144 #ifndef __sparc__
 145         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 146 #endif
 147         dump.signal = signr;
 148         dump_thread(regs, &dump);
 149
 150 /* If the size of the dump file exceeds the rlimit, then see what would happen
 151    if we wrote the stack, but not the data area.  */
 152 #ifdef __sparc__
 153         if ((dump.u_dsize+dump.u_ssize) >
 154             current->rlim[RLIMIT_CORE].rlim_cur)
 155                 dump.u_dsize = 0;
 156 #else
 157         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 158             current->rlim[RLIMIT_CORE].rlim_cur)
 159                 dump.u_dsize = 0;
 160 #endif
 161
 162 /* Make sure we have enough room to write the stack and data areas. */
 163 #ifdef __sparc__
 164         if ((dump.u_ssize) >
 165             current->rlim[RLIMIT_CORE].rlim_cur)
 166                 dump.u_ssize = 0;
 167 #else
 168         if ((dump.u_ssize+1) * PAGE_SIZE >
 169             current->rlim[RLIMIT_CORE].rlim_cur)
 170                 dump.u_ssize = 0;
 171 #endif
 172
 173 /* make sure we actually have a data and stack area to dump */
 174         set_fs(USER_DS);
 175 #ifdef __sparc__
 176         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 177                 dump.u_dsize = 0;
 178         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 179                 dump.u_ssize = 0;
 180 #else
 181         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 182                 dump.u_dsize = 0;
 183         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 184                 dump.u_ssize = 0;
 185 #endif
 186
 187         set_fs(KERNEL_DS);
 188 /* struct user */
 189         DUMP_WRITE(&dump,sizeof(dump));
 190 /* Now dump all of the user data.  Include malloced stuff as well */
 191 #ifndef __sparc__
 192         DUMP_SEEK(PAGE_SIZE);
 193 #endif
 194 /* now we start writing out the user space info */
 195         set_fs(USER_DS);
 196 /* Dump the data area */
 197         if (dump.u_dsize != 0) {
 198                 dump_start = START_DATA(dump);
 199 #ifdef __sparc__
 200                 dump_size = dump.u_dsize;
 201 #else
 202                 dump_size = dump.u_dsize << PAGE_SHIFT;
 203 #endif
 204                 DUMP_WRITE(dump_start,dump_size);
 205         }
 206 /* Now prepare to dump the stack area */
 207         if (dump.u_ssize != 0) {
 208                 dump_start = START_STACK(dump);
 209 #ifdef __sparc__
 210                 dump_size = dump.u_ssize;
 211 #else
 212                 dump_size = dump.u_ssize << PAGE_SHIFT;
 213 #endif
 214                 DUMP_WRITE(dump_start,dump_size);
 215         }
 216 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 217         set_fs(KERNEL_DS);
 218         DUMP_WRITE(current,sizeof(*current));
 219 close_coredump:
 220         filp_close(file, NULL);
 221 end_coredump:
 222         set_fs(fs);
 223         return has_dumped;
 224 }
 225
 226 static int
 227 aout_core_dump(long signr, struct pt_regs * regs)
 228 {
 229         int retval;
 230
 231         MOD_INC_USE_COUNT;
 232         retval = do_aout_core_dump(signr, regs);
 233         MOD_DEC_USE_COUNT;
 234         return retval;
 235 }
 236
 237 /*
 238  * create_aout_tables() parses the env- and arg-strings in new user
 239  * memory and creates the pointer tables from them, and puts their
 240  * addresses on the "stack", returning the new stack pointer value.
 241  */
 242 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 243 {
 244         char **argv, **envp;
 245         unsigned long * sp;
 246         int argc = bprm->argc;
 247         int envc = bprm->envc;
 248
 249         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 250 #ifdef __sparc__
 251         /* This imposes the proper stack alignment for a new process. */
 252         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 253         if ((envc+argc+3)&1) --sp;
 254 #endif
 255 #ifdef __alpha__
 256 /* whee.. test-programs are so much fun. */
 257         put_user(0, --sp);
 258         put_user(0, --sp);
 259         if (bprm->loader) {
 260                 put_user(0, --sp);
 261                 put_user(0x3eb, --sp);
 262                 put_user(bprm->loader, --sp);
 263                 put_user(0x3ea, --sp);
 264         }
 265         put_user(bprm->exec, --sp);
 266         put_user(0x3e9, --sp);
 267 #endif
 268         sp -= envc+1;
 269         envp = (char **) sp;
 270         sp -= argc+1;
 271         argv = (char **) sp;
 272 #if defined(__i386__) || defined(__mc68000__)
 273         put_user((unsigned long) envp,--sp);
 274         put_user((unsigned long) argv,--sp);
 275 #endif
 276         put_user(argc,--sp);
 277         current->mm->arg_start = (unsigned long) p;
 278         while (argc-->0) {
 279                 char c;
 280                 put_user(p,argv++);
 281                 do {
 282                         get_user(c,p++);
 283                 } while (c);
 284         }
 285         put_user(NULL,argv);
 286         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 287         while (envc-->0) {
 288                 char c;
 289                 put_user(p,envp++);
 290                 do {
 291                         get_user(c,p++);
 292                 } while (c);
 293         }
 294         put_user(NULL,envp);
 295         current->mm->env_end = (unsigned long) p;
 296         return sp;
 297 }
 298
 299 /*
 300  * These are the functions used to load a.out style executables and shared
 301  * libraries.  There is no binary dependent code anywhere else.
 302  */
 303
 304 static inline int do_load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 305 {
 306         struct exec ex;
 307         struct file * file;
 308         int fd;
 309         unsigned long error;
 310         unsigned long p = bprm->p;
 311         unsigned long fd_offset;
 312         unsigned long rlim;
 313         int retval;
 314
 315         ex = *((struct exec *) bprm->buf);              /* exec-header */
 316         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 317              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 318             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 319             bprm->dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 320                 return -ENOEXEC;
 321         }
 322
 323         fd_offset = N_TXTOFF(ex);
 324
 325 #ifdef __i386__
 326         if (N_MAGIC(ex) == ZMAGIC && fd_offset != BLOCK_SIZE) {
 327                 printk(KERN_NOTICE "N_TXTOFF != BLOCK_SIZE. See a.out.h.\n");
 328                 return -ENOEXEC;
 329         }
 330
 331         if (N_MAGIC(ex) == ZMAGIC && ex.a_text &&
 332             bprm->dentry->d_inode->i_op &&
 333             bprm->dentry->d_inode->i_op->bmap &&
 334             (fd_offset < bprm->dentry->d_inode->i_sb->s_blocksize)) {
 335                 printk(KERN_NOTICE "N_TXTOFF < BLOCK_SIZE. Please convert binary.\n");
 336                 return -ENOEXEC;
 337         }
 338 #endif
 339
 340         /* Check initial limits. This avoids letting people circumvent
 341          * size limits imposed on them by creating programs with large
 342          * arrays in the data or bss.
 343          */
 344         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 345         if (rlim >= RLIM_INFINITY)
 346                 rlim = ~0;
 347         if (ex.a_data + ex.a_bss > rlim)
 348                 return -ENOMEM;
 349
 350         /* Flush all traces of the currently running executable */
 351         retval = flush_old_exec(bprm);
 352         if (retval)
 353                 return retval;
 354
 355         /* OK, This is the point of no return */
 356         current->personality = PER_LINUX;
 357
 358 #if defined(__sparc__) && !defined(__sparc_v9__)
 359         memcpy(&current->tss.core_exec, &ex, sizeof(struct exec));
 360 #endif
 361
 362         current->mm->end_code = ex.a_text +
 363                 (current->mm->start_code = N_TXTADDR(ex));
 364         current->mm->end_data = ex.a_data +
 365                 (current->mm->start_data = N_DATADDR(ex));
 366         current->mm->brk = ex.a_bss +
 367                 (current->mm->start_brk = N_BSSADDR(ex));
 368
 369         current->mm->rss = 0;
 370         current->mm->mmap = NULL;
 371         compute_creds(bprm);
 372         current->flags &= ~PF_FORKNOEXEC;
 373 #ifdef __sparc__
 374         if (N_MAGIC(ex) == NMAGIC) {
 375                 /* Fuck me plenty... */
 376                 error = do_mmap(NULL, N_TXTADDR(ex), ex.a_text,
 377                                 PROT_READ|PROT_WRITE|PROT_EXEC,
 378                                 MAP_FIXED|MAP_PRIVATE, 0);
 379                 read_exec(bprm->dentry, fd_offset, (char *) N_TXTADDR(ex),
 380                           ex.a_text, 0);
 381                 error = do_mmap(NULL, N_DATADDR(ex), ex.a_data,
 382                                 PROT_READ|PROT_WRITE|PROT_EXEC,
 383                                 MAP_FIXED|MAP_PRIVATE, 0);
 384                 read_exec(bprm->dentry, fd_offset + ex.a_text, (char *) N_DATADDR(ex),
 385                           ex.a_data, 0);
 386                 goto beyond_if;
 387         }
 388 #endif
 389
 390         if (N_MAGIC(ex) == OMAGIC) {
 391 #if defined(__alpha__) || defined(__sparc__)
 392                 do_mmap(NULL, N_TXTADDR(ex) & PAGE_MASK,
 393                         ex.a_text+ex.a_data + PAGE_SIZE - 1,
 394                         PROT_READ|PROT_WRITE|PROT_EXEC,
 395                         MAP_FIXED|MAP_PRIVATE, 0);
 396                 read_exec(bprm->dentry, fd_offset, (char *) N_TXTADDR(ex),
 397                           ex.a_text+ex.a_data, 0);
 398 #else
 399                 do_mmap(NULL, 0, ex.a_text+ex.a_data,
 400                         PROT_READ|PROT_WRITE|PROT_EXEC,
 401                         MAP_FIXED|MAP_PRIVATE, 0);
 402                 read_exec(bprm->dentry, 32, (char *) 0, ex.a_text+ex.a_data, 0);
 403 #endif
 404                 flush_icache_range((unsigned long) 0,
 405                                    (unsigned long) ex.a_text+ex.a_data);
 406         } else {
 407                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 408                     (N_MAGIC(ex) != NMAGIC))
 409                         printk(KERN_NOTICE "executable not page aligned\n");
 410
 411                 fd = open_dentry(bprm->dentry, O_RDONLY);
 412                 if (fd < 0)
 413                         return fd;
 414                 file = fcheck(fd);
 415
 416                 if (!file->f_op || !file->f_op->mmap) {
 417                         sys_close(fd);
 418                         do_mmap(NULL, 0, ex.a_text+ex.a_data,
 419                                 PROT_READ|PROT_WRITE|PROT_EXEC,
 420                                 MAP_FIXED|MAP_PRIVATE, 0);
 421                         read_exec(bprm->dentry, fd_offset,
 422                                   (char *) N_TXTADDR(ex), ex.a_text+ex.a_data, 0);
 423                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 424                                            (unsigned long) N_TXTADDR(ex) +
 425                                            ex.a_text+ex.a_data);
 426                         goto beyond_if;
 427                 }
 428
 429                 error = do_mmap(file, N_TXTADDR(ex), ex.a_text,
 430                         PROT_READ | PROT_EXEC,
 431                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 432                         fd_offset);
 433
 434                 if (error != N_TXTADDR(ex)) {
 435                         sys_close(fd);
 436                         send_sig(SIGKILL, current, 0);
 437                         return error;
 438                 }
 439
 440                 error = do_mmap(file, N_DATADDR(ex), ex.a_data,
 441                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 442                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 443                                 fd_offset + ex.a_text);
 444                 sys_close(fd);
 445                 if (error != N_DATADDR(ex)) {
 446                         send_sig(SIGKILL, current, 0);
 447                         return error;
 448                 }
 449         }
 450 beyond_if:
 451         if (current->exec_domain && current->exec_domain->module)
 452                 __MOD_DEC_USE_COUNT(current->exec_domain->module);
 453         if (current->binfmt && current->binfmt->module)
 454                 __MOD_DEC_USE_COUNT(current->binfmt->module);
 455         current->exec_domain = lookup_exec_domain(current->personality);
 456         current->binfmt = &aout_format;
 457         if (current->exec_domain && current->exec_domain->module)
 458                 __MOD_INC_USE_COUNT(current->exec_domain->module);
 459         if (current->binfmt && current->binfmt->module)
 460                 __MOD_INC_USE_COUNT(current->binfmt->module);
 461
 462         set_brk(current->mm->start_brk, current->mm->brk);
 463
 464         p = setup_arg_pages(p, bprm);
 465
 466         p = (unsigned long) create_aout_tables((char *)p, bprm);
 467         current->mm->start_stack = p;
 468 #ifdef __alpha__
 469         regs->gp = ex.a_gpvalue;
 470 #endif
 471         start_thread(regs, ex.a_entry, p);
 472         if (current->flags & PF_PTRACED)
 473                 send_sig(SIGTRAP, current, 0);
 474         return 0;
 475 }
 476
 477
 478 static int
 479 load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 480 {
 481         int retval;
 482
 483         MOD_INC_USE_COUNT;
 484         retval = do_load_aout_binary(bprm, regs);
 485         MOD_DEC_USE_COUNT;
 486         return retval;
 487 }
 488
 489 static inline int
 490 do_load_aout_library(int fd)
 491 {
 492         struct file * file;
 493         struct inode * inode;
 494         unsigned long bss, start_addr, len;
 495         unsigned long error;
 496         int retval;
 497         loff_t offset = 0;
 498         struct exec ex;
 499
 500         retval = -EACCES;
 501         file = fget(fd);
 502         if (!file)
 503                 goto out;
 504         if (!file->f_op)
 505                 goto out_putf;
 506         inode = file->f_dentry->d_inode;
 507
 508         retval = -ENOEXEC;
 509         /* N.B. Save current fs? */
 510         set_fs(KERNEL_DS);
 511         error = file->f_op->read(file, (char *) &ex, sizeof(ex), &offset);
 512         set_fs(USER_DS);
 513         if (error != sizeof(ex))
 514                 goto out_putf;
 515
 516         /* We come in here for the regular a.out style of shared libraries */
 517         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 518             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 519             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 520                 goto out_putf;
 521         }
 522
 523         if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
 524             (N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
 525                 printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
 526                 goto out_putf;
 527         }
 528
 529         if (N_FLAGS(ex))
 530                 goto out_putf;
 531
 532         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 533            this off to get the starting address for the page */
 534
 535         start_addr =  ex.a_entry & 0xfffff000;
 536
 537         /* Now use mmap to map the library into memory. */
 538         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 539                         PROT_READ | PROT_WRITE | PROT_EXEC,
 540                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 541                         N_TXTOFF(ex));
 542         retval = error;
 543         if (error != start_addr)
 544                 goto out_putf;
 545
 546         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 547         bss = ex.a_text + ex.a_data + ex.a_bss;
 548         if (bss > len) {
 549                 error = do_mmap(NULL, start_addr + len, bss - len,
 550                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 551                                 MAP_PRIVATE | MAP_FIXED, 0);
 552                 retval = error;
 553                 if (error != start_addr + len)
 554                         goto out_putf;
 555         }
 556         retval = 0;
 557
 558 out_putf:
 559         fput(file);
 560 out:
 561         return retval;
 562 }
 563
 564 static int
 565 load_aout_library(int fd)
 566 {
 567         int retval;
 568
 569         MOD_INC_USE_COUNT;
 570         retval = do_load_aout_library(fd);
 571         MOD_DEC_USE_COUNT;
 572         return retval;
 573 }
 574
 575
 576 int __init init_aout_binfmt(void)
 577 {
 578         return register_binfmt(&aout_format);
 579 }
 580
 581 #ifdef MODULE
 582 int init_module(void) {
 583         return init_aout_binfmt();
 584 }
 585
 586 void cleanup_module( void) {
 587         unregister_binfmt(&aout_format);
 588 }
 589 #endif