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/pgalloc.h>
  31
  32 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  33 static int load_aout_library(struct file*);
  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, THIS_MODULE, load_aout_binary, load_aout_library, aout_core_dump, PAGE_SIZE
  40 };
  41
  42 static void set_brk(unsigned long start, unsigned long end)
  43 {
  44         start = PAGE_ALIGN(start);
  45         end = PAGE_ALIGN(end);
  46         if (end <= start)
  47                 return;
  48         do_brk(start, end - start);
  49 }
  50
  51 /*
  52  * These are the only things you should do on a core-file: use only these
  53  * macros to write out all the necessary info.
  54  */
  55
  56 static int dump_write(struct file *file, const void *addr, int nr)
  57 {
  58         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  59 }
  60
  61 #define DUMP_WRITE(addr, nr)    \
  62         if (!dump_write(file, (void *)(addr), (nr))) \
  63                 goto end_coredump;
  64
  65 #define DUMP_SEEK(offset) \
  66 if (file->f_op->llseek) { \
  67         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  68                 goto end_coredump; \
  69 } else file->f_pos = (offset)
  70
  71 /*
  72  * Routine writes a core dump image in the current directory.
  73  * Currently only a stub-function.
  74  *
  75  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  76  * changed due to the set[u|g]id. It's enforced by the "current->dumpable"
  77  * field, which also makes sure the core-dumps won't be recursive if the
  78  * dumping of the process results in another error..
  79  */
  80
  81 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
  82 {
  83         mm_segment_t fs;
  84         int has_dumped = 0;
  85         unsigned long dump_start, dump_size;
  86         struct user dump;
  87 #if defined(__alpha__)
  88 #       define START_DATA(u)    (u.start_data)
  89 #elif defined(__arm__)
  90 #       define START_DATA(u)    ((u.u_tsize << PAGE_SHIFT) + u.start_code)
  91 #elif defined(__sparc__)
  92 #       define START_DATA(u)    (u.u_tsize)
  93 #elif defined(__i386__) || defined(__mc68000__)
  94 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
  95 #endif
  96 #ifdef __sparc__
  97 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
  98 #else
  99 #       define START_STACK(u)   (u.start_stack)
 100 #endif
 101
 102         fs = get_fs();
 103         set_fs(KERNEL_DS);
 104         has_dumped = 1;
 105         current->flags |= PF_DUMPCORE;
 106         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 107 #ifndef __sparc__
 108         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 109 #endif
 110         dump.signal = signr;
 111         dump_thread(regs, &dump);
 112
 113 /* If the size of the dump file exceeds the rlimit, then see what would happen
 114    if we wrote the stack, but not the data area.  */
 115 #ifdef __sparc__
 116         if ((dump.u_dsize+dump.u_ssize) >
 117             current->rlim[RLIMIT_CORE].rlim_cur)
 118                 dump.u_dsize = 0;
 119 #else
 120         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 121             current->rlim[RLIMIT_CORE].rlim_cur)
 122                 dump.u_dsize = 0;
 123 #endif
 124
 125 /* Make sure we have enough room to write the stack and data areas. */
 126 #ifdef __sparc__
 127         if ((dump.u_ssize) >
 128             current->rlim[RLIMIT_CORE].rlim_cur)
 129                 dump.u_ssize = 0;
 130 #else
 131         if ((dump.u_ssize+1) * PAGE_SIZE >
 132             current->rlim[RLIMIT_CORE].rlim_cur)
 133                 dump.u_ssize = 0;
 134 #endif
 135
 136 /* make sure we actually have a data and stack area to dump */
 137         set_fs(USER_DS);
 138 #ifdef __sparc__
 139         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 140                 dump.u_dsize = 0;
 141         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 142                 dump.u_ssize = 0;
 143 #else
 144         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 145                 dump.u_dsize = 0;
 146         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 147                 dump.u_ssize = 0;
 148 #endif
 149
 150         set_fs(KERNEL_DS);
 151 /* struct user */
 152         DUMP_WRITE(&dump,sizeof(dump));
 153 /* Now dump all of the user data.  Include malloced stuff as well */
 154 #ifndef __sparc__
 155         DUMP_SEEK(PAGE_SIZE);
 156 #endif
 157 /* now we start writing out the user space info */
 158         set_fs(USER_DS);
 159 /* Dump the data area */
 160         if (dump.u_dsize != 0) {
 161                 dump_start = START_DATA(dump);
 162 #ifdef __sparc__
 163                 dump_size = dump.u_dsize;
 164 #else
 165                 dump_size = dump.u_dsize << PAGE_SHIFT;
 166 #endif
 167                 DUMP_WRITE(dump_start,dump_size);
 168         }
 169 /* Now prepare to dump the stack area */
 170         if (dump.u_ssize != 0) {
 171                 dump_start = START_STACK(dump);
 172 #ifdef __sparc__
 173                 dump_size = dump.u_ssize;
 174 #else
 175                 dump_size = dump.u_ssize << PAGE_SHIFT;
 176 #endif
 177                 DUMP_WRITE(dump_start,dump_size);
 178         }
 179 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 180         set_fs(KERNEL_DS);
 181         DUMP_WRITE(current,sizeof(*current));
 182 end_coredump:
 183         set_fs(fs);
 184         return has_dumped;
 185 }
 186
 187 /*
 188  * create_aout_tables() parses the env- and arg-strings in new user
 189  * memory and creates the pointer tables from them, and puts their
 190  * addresses on the "stack", returning the new stack pointer value.
 191  */
 192 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 193 {
 194         char **argv, **envp;
 195         unsigned long * sp;
 196         int argc = bprm->argc;
 197         int envc = bprm->envc;
 198
 199         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 200 #ifdef __sparc__
 201         /* This imposes the proper stack alignment for a new process. */
 202         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 203         if ((envc+argc+3)&1) --sp;
 204 #endif
 205 #ifdef __alpha__
 206 /* whee.. test-programs are so much fun. */
 207         put_user(0, --sp);
 208         put_user(0, --sp);
 209         if (bprm->loader) {
 210                 put_user(0, --sp);
 211                 put_user(0x3eb, --sp);
 212                 put_user(bprm->loader, --sp);
 213                 put_user(0x3ea, --sp);
 214         }
 215         put_user(bprm->exec, --sp);
 216         put_user(0x3e9, --sp);
 217 #endif
 218         sp -= envc+1;
 219         envp = (char **) sp;
 220         sp -= argc+1;
 221         argv = (char **) sp;
 222 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__)
 223         put_user((unsigned long) envp,--sp);
 224         put_user((unsigned long) argv,--sp);
 225 #endif
 226         put_user(argc,--sp);
 227         current->mm->arg_start = (unsigned long) p;
 228         while (argc-->0) {
 229                 char c;
 230                 put_user(p,argv++);
 231                 do {
 232                         get_user(c,p++);
 233                 } while (c);
 234         }
 235         put_user(NULL,argv);
 236         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 237         while (envc-->0) {
 238                 char c;
 239                 put_user(p,envp++);
 240                 do {
 241                         get_user(c,p++);
 242                 } while (c);
 243         }
 244         put_user(NULL,envp);
 245         current->mm->env_end = (unsigned long) p;
 246         return sp;
 247 }
 248
 249 /*
 250  * These are the functions used to load a.out style executables and shared
 251  * libraries.  There is no binary dependent code anywhere else.
 252  */
 253
 254 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 255 {
 256         struct exec ex;
 257         unsigned long error;
 258         unsigned long fd_offset;
 259         unsigned long rlim;
 260         int retval;
 261
 262         ex = *((struct exec *) bprm->buf);              /* exec-header */
 263         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 264              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 265             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 266             bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 267                 return -ENOEXEC;
 268         }
 269
 270         fd_offset = N_TXTOFF(ex);
 271
 272         /* Check initial limits. This avoids letting people circumvent
 273          * size limits imposed on them by creating programs with large
 274          * arrays in the data or bss.
 275          */
 276         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 277         if (rlim >= RLIM_INFINITY)
 278                 rlim = ~0;
 279         if (ex.a_data + ex.a_bss > rlim)
 280                 return -ENOMEM;
 281
 282         /* Flush all traces of the currently running executable */
 283         retval = flush_old_exec(bprm);
 284         if (retval)
 285                 return retval;
 286
 287         /* OK, This is the point of no return */
 288 #if !defined(__sparc__)
 289         set_personality(PER_LINUX);
 290 #else
 291         set_personality(PER_SUNOS);
 292 #if !defined(__sparc_v9__)
 293         memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
 294 #endif
 295 #endif
 296
 297         current->mm->end_code = ex.a_text +
 298                 (current->mm->start_code = N_TXTADDR(ex));
 299         current->mm->end_data = ex.a_data +
 300                 (current->mm->start_data = N_DATADDR(ex));
 301         current->mm->brk = ex.a_bss +
 302                 (current->mm->start_brk = N_BSSADDR(ex));
 303
 304         current->mm->rss = 0;
 305         current->mm->mmap = NULL;
 306         compute_creds(bprm);
 307         current->flags &= ~PF_FORKNOEXEC;
 308 #ifdef __sparc__
 309         if (N_MAGIC(ex) == NMAGIC) {
 310                 loff_t pos = fd_offset;
 311                 /* Fuck me plenty... */
 312                 /* <AOL></AOL> */
 313                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 314                 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
 315                           ex.a_text, &pos);
 316                 error = do_brk(N_DATADDR(ex), ex.a_data);
 317                 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
 318                           ex.a_data, &pos);
 319                 goto beyond_if;
 320         }
 321 #endif
 322
 323         if (N_MAGIC(ex) == OMAGIC) {
 324                 unsigned long text_addr, map_size;
 325                 loff_t pos;
 326
 327                 text_addr = N_TXTADDR(ex);
 328
 329 #if defined(__alpha__) || defined(__sparc__)
 330                 pos = fd_offset;
 331                 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
 332 #else
 333                 pos = 32;
 334                 map_size = ex.a_text+ex.a_data;
 335 #endif
 336
 337                 error = do_brk(text_addr & PAGE_MASK, map_size);
 338                 if (error != (text_addr & PAGE_MASK)) {
 339                         send_sig(SIGKILL, current, 0);
 340                         return error;
 341                 }
 342
 343                 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
 344                           ex.a_text+ex.a_data, &pos);
 345                 if (error < 0) {
 346                         send_sig(SIGKILL, current, 0);
 347                         return error;
 348                 }
 349
 350                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 351         } else {
 352                 static unsigned long error_time, error_time2;
 353                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 354                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 355                 {
 356                         printk(KERN_NOTICE "executable not page aligned\n");
 357                         error_time2 = jiffies;
 358                 }
 359
 360                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 361                     (jiffies-error_time) > 5*HZ)
 362                 {
 363                         printk(KERN_WARNING
 364                                "fd_offset is not page aligned. Please convert program: %s\n",
 365                                bprm->file->f_dentry->d_name.name);
 366                         error_time = jiffies;
 367                 }
 368
 369                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 370                         loff_t pos = fd_offset;
 371                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 372                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 373                                         ex.a_text+ex.a_data, &pos);
 374                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 375                                            (unsigned long) N_TXTADDR(ex) +
 376                                            ex.a_text+ex.a_data);
 377                         goto beyond_if;
 378                 }
 379
 380                 down(&current->mm->mmap_sem);
 381                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 382                         PROT_READ | PROT_EXEC,
 383                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 384                         fd_offset);
 385                 up(&current->mm->mmap_sem);
 386
 387                 if (error != N_TXTADDR(ex)) {
 388                         send_sig(SIGKILL, current, 0);
 389                         return error;
 390                 }
 391
 392                 down(&current->mm->mmap_sem);
 393                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 394                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 395                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 396                                 fd_offset + ex.a_text);
 397                 up(&current->mm->mmap_sem);
 398                 if (error != N_DATADDR(ex)) {
 399                         send_sig(SIGKILL, current, 0);
 400                         return error;
 401                 }
 402         }
 403 beyond_if:
 404         set_binfmt(&aout_format);
 405
 406         set_brk(current->mm->start_brk, current->mm->brk);
 407
 408         retval = setup_arg_pages(bprm);
 409         if (retval < 0) {
 410                 /* Someone check-me: is this error path enough? */
 411                 send_sig(SIGKILL, current, 0);
 412                 return retval;
 413         }
 414
 415         current->mm->start_stack =
 416                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 417 #ifdef __alpha__
 418         regs->gp = ex.a_gpvalue;
 419 #endif
 420         start_thread(regs, ex.a_entry, current->mm->start_stack);
 421         if (current->ptrace & PT_PTRACED)
 422                 send_sig(SIGTRAP, current, 0);
 423         return 0;
 424 }
 425
 426 static int load_aout_library(struct file *file)
 427 {
 428         struct inode * inode;
 429         unsigned long bss, start_addr, len;
 430         unsigned long error;
 431         int retval;
 432         struct exec ex;
 433
 434         inode = file->f_dentry->d_inode;
 435
 436         retval = -ENOEXEC;
 437         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 438         if (error != sizeof(ex))
 439                 goto out;
 440
 441         /* We come in here for the regular a.out style of shared libraries */
 442         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 443             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 444             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 445                 goto out;
 446         }
 447
 448         if (N_FLAGS(ex))
 449                 goto out;
 450
 451         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 452            this off to get the starting address for the page */
 453
 454         start_addr =  ex.a_entry & 0xfffff000;
 455
 456         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 457                 static unsigned long error_time;
 458                 loff_t pos = N_TXTOFF(ex);
 459
 460                 if ((jiffies-error_time) > 5*HZ)
 461                 {
 462                         printk(KERN_WARNING
 463                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 464                                file->f_dentry->d_name.name);
 465                         error_time = jiffies;
 466                 }
 467
 468                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 469
 470                 file->f_op->read(file, (char *)start_addr,
 471                         ex.a_text + ex.a_data, &pos);
 472                 flush_icache_range((unsigned long) start_addr,
 473                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 474
 475                 retval = 0;
 476                 goto out;
 477         }
 478         /* Now use mmap to map the library into memory. */
 479         down(&current->mm->mmap_sem);
 480         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 481                         PROT_READ | PROT_WRITE | PROT_EXEC,
 482                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 483                         N_TXTOFF(ex));
 484         up(&current->mm->mmap_sem);
 485         retval = error;
 486         if (error != start_addr)
 487                 goto out;
 488
 489         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 490         bss = ex.a_text + ex.a_data + ex.a_bss;
 491         if (bss > len) {
 492                 error = do_brk(start_addr + len, bss - len);
 493                 retval = error;
 494                 if (error != start_addr + len)
 495                         goto out;
 496         }
 497         retval = 0;
 498 out:
 499         return retval;
 500 }
 501
 502 static int __init init_aout_binfmt(void)
 503 {
 504         return register_binfmt(&aout_format);
 505 }
 506
 507 static void __exit exit_aout_binfmt(void)
 508 {
 509         unregister_binfmt(&aout_format);
 510 }
 511
 512 EXPORT_NO_SYMBOLS;
 513
 514 module_init(init_aout_binfmt);
 515 module_exit(exit_aout_binfmt);