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/time.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/slab.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 #include <asm/cacheflush.h>
  32
  33 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  34 static int load_aout_library(struct file*);
  35 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
  36
  37 extern void dump_thread(struct pt_regs *, struct user *);
  38
  39 static struct linux_binfmt aout_format = {
  40         .module         = THIS_MODULE,
  41         .load_binary    = load_aout_binary,
  42         .load_shlib     = load_aout_library,
  43         .core_dump      = aout_core_dump,
  44         .min_coredump   = PAGE_SIZE
  45 };
  46
  47 static void set_brk(unsigned long start, unsigned long end)
  48 {
  49         start = PAGE_ALIGN(start);
  50         end = PAGE_ALIGN(end);
  51         if (end <= start)
  52                 return;
  53         do_brk(start, end - start);
  54 }
  55
  56 /*
  57  * These are the only things you should do on a core-file: use only these
  58  * macros to write out all the necessary info.
  59  */
  60
  61 static int dump_write(struct file *file, const void *addr, int nr)
  62 {
  63         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  64 }
  65
  66 #define DUMP_WRITE(addr, nr)    \
  67         if (!dump_write(file, (void *)(addr), (nr))) \
  68                 goto end_coredump;
  69
  70 #define DUMP_SEEK(offset) \
  71 if (file->f_op->llseek) { \
  72         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  73                 goto end_coredump; \
  74 } else file->f_pos = (offset)
  75
  76 /*
  77  * Routine writes a core dump image in the current directory.
  78  * Currently only a stub-function.
  79  *
  80  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  81  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
  82  * field, which also makes sure the core-dumps won't be recursive if the
  83  * dumping of the process results in another error..
  84  */
  85
  86 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
  87 {
  88         mm_segment_t fs;
  89         int has_dumped = 0;
  90         unsigned long dump_start, dump_size;
  91         struct user dump;
  92 #if defined(__alpha__)
  93 #       define START_DATA(u)    (u.start_data)
  94 #elif defined(__arm__)
  95 #       define START_DATA(u)    ((u.u_tsize << PAGE_SHIFT) + u.start_code)
  96 #elif defined(__sparc__)
  97 #       define START_DATA(u)    (u.u_tsize)
  98 #elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
  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 /*
 193  * create_aout_tables() parses the env- and arg-strings in new user
 194  * memory and creates the pointer tables from them, and puts their
 195  * addresses on the "stack", returning the new stack pointer value.
 196  */
 197 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 198 {
 199         char **argv, **envp;
 200         unsigned long * sp;
 201         int argc = bprm->argc;
 202         int envc = bprm->envc;
 203
 204         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 205 #ifdef __sparc__
 206         /* This imposes the proper stack alignment for a new process. */
 207         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 208         if ((envc+argc+3)&1) --sp;
 209 #endif
 210 #ifdef __alpha__
 211 /* whee.. test-programs are so much fun. */
 212         put_user(0, --sp);
 213         put_user(0, --sp);
 214         if (bprm->loader) {
 215                 put_user(0, --sp);
 216                 put_user(0x3eb, --sp);
 217                 put_user(bprm->loader, --sp);
 218                 put_user(0x3ea, --sp);
 219         }
 220         put_user(bprm->exec, --sp);
 221         put_user(0x3e9, --sp);
 222 #endif
 223         sp -= envc+1;
 224         envp = (char **) sp;
 225         sp -= argc+1;
 226         argv = (char **) sp;
 227 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
 228         put_user((unsigned long) envp,--sp);
 229         put_user((unsigned long) argv,--sp);
 230 #endif
 231         put_user(argc,--sp);
 232         current->mm->arg_start = (unsigned long) p;
 233         while (argc-->0) {
 234                 char c;
 235                 put_user(p,argv++);
 236                 do {
 237                         get_user(c,p++);
 238                 } while (c);
 239         }
 240         put_user(NULL,argv);
 241         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 242         while (envc-->0) {
 243                 char c;
 244                 put_user(p,envp++);
 245                 do {
 246                         get_user(c,p++);
 247                 } while (c);
 248         }
 249         put_user(NULL,envp);
 250         current->mm->env_end = (unsigned long) p;
 251         return sp;
 252 }
 253
 254 /*
 255  * These are the functions used to load a.out style executables and shared
 256  * libraries.  There is no binary dependent code anywhere else.
 257  */
 258
 259 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 260 {
 261         struct exec ex;
 262         unsigned long error;
 263         unsigned long fd_offset;
 264         unsigned long rlim;
 265         int retval;
 266
 267         ex = *((struct exec *) bprm->buf);              /* exec-header */
 268         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 269              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 270             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 271             i_size_read(bprm->file->f_dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 272                 return -ENOEXEC;
 273         }
 274
 275         fd_offset = N_TXTOFF(ex);
 276
 277         /* Check initial limits. This avoids letting people circumvent
 278          * size limits imposed on them by creating programs with large
 279          * arrays in the data or bss.
 280          */
 281         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 282         if (rlim >= RLIM_INFINITY)
 283                 rlim = ~0;
 284         if (ex.a_data + ex.a_bss > rlim)
 285                 return -ENOMEM;
 286
 287         /* Flush all traces of the currently running executable */
 288         retval = flush_old_exec(bprm);
 289         if (retval)
 290                 return retval;
 291
 292         /* OK, This is the point of no return */
 293 #if defined(__alpha__)
 294         SET_AOUT_PERSONALITY(bprm, ex);
 295 #elif defined(__sparc__)
 296         set_personality(PER_SUNOS);
 297 #if !defined(__sparc_v9__)
 298         memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
 299 #endif
 300 #else
 301         set_personality(PER_LINUX);
 302 #endif
 303
 304         current->mm->end_code = ex.a_text +
 305                 (current->mm->start_code = N_TXTADDR(ex));
 306         current->mm->end_data = ex.a_data +
 307                 (current->mm->start_data = N_DATADDR(ex));
 308         current->mm->brk = ex.a_bss +
 309                 (current->mm->start_brk = N_BSSADDR(ex));
 310         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 311
 312         current->mm->rss = 0;
 313         current->mm->mmap = NULL;
 314         compute_creds(bprm);
 315         current->flags &= ~PF_FORKNOEXEC;
 316 #ifdef __sparc__
 317         if (N_MAGIC(ex) == NMAGIC) {
 318                 loff_t pos = fd_offset;
 319                 /* Fuck me plenty... */
 320                 /* <AOL></AOL> */
 321                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 322                 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
 323                           ex.a_text, &pos);
 324                 error = do_brk(N_DATADDR(ex), ex.a_data);
 325                 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
 326                           ex.a_data, &pos);
 327                 goto beyond_if;
 328         }
 329 #endif
 330
 331         if (N_MAGIC(ex) == OMAGIC) {
 332                 unsigned long text_addr, map_size;
 333                 loff_t pos;
 334
 335                 text_addr = N_TXTADDR(ex);
 336
 337 #if defined(__alpha__) || defined(__sparc__)
 338                 pos = fd_offset;
 339                 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
 340 #else
 341                 pos = 32;
 342                 map_size = ex.a_text+ex.a_data;
 343 #endif
 344
 345                 error = do_brk(text_addr & PAGE_MASK, map_size);
 346                 if (error != (text_addr & PAGE_MASK)) {
 347                         send_sig(SIGKILL, current, 0);
 348                         return error;
 349                 }
 350
 351                 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
 352                           ex.a_text+ex.a_data, &pos);
 353                 if ((signed long)error < 0) {
 354                         send_sig(SIGKILL, current, 0);
 355                         return error;
 356                 }
 357
 358                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 359         } else {
 360                 static unsigned long error_time, error_time2;
 361                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 362                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 363                 {
 364                         printk(KERN_NOTICE "executable not page aligned\n");
 365                         error_time2 = jiffies;
 366                 }
 367
 368                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 369                     (jiffies-error_time) > 5*HZ)
 370                 {
 371                         printk(KERN_WARNING
 372                                "fd_offset is not page aligned. Please convert program: %s\n",
 373                                bprm->file->f_dentry->d_name.name);
 374                         error_time = jiffies;
 375                 }
 376
 377                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 378                         loff_t pos = fd_offset;
 379                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 380                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 381                                         ex.a_text+ex.a_data, &pos);
 382                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 383                                            (unsigned long) N_TXTADDR(ex) +
 384                                            ex.a_text+ex.a_data);
 385                         goto beyond_if;
 386                 }
 387
 388                 down_write(&current->mm->mmap_sem);
 389                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 390                         PROT_READ | PROT_EXEC,
 391                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 392                         fd_offset);
 393                 up_write(&current->mm->mmap_sem);
 394
 395                 if (error != N_TXTADDR(ex)) {
 396                         send_sig(SIGKILL, current, 0);
 397                         return error;
 398                 }
 399
 400                 down_write(&current->mm->mmap_sem);
 401                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 402                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 403                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 404                                 fd_offset + ex.a_text);
 405                 up_write(&current->mm->mmap_sem);
 406                 if (error != N_DATADDR(ex)) {
 407                         send_sig(SIGKILL, current, 0);
 408                         return error;
 409                 }
 410         }
 411 beyond_if:
 412         set_binfmt(&aout_format);
 413
 414         set_brk(current->mm->start_brk, current->mm->brk);
 415
 416         retval = setup_arg_pages(bprm);
 417         if (retval < 0) {
 418                 /* Someone check-me: is this error path enough? */
 419                 send_sig(SIGKILL, current, 0);
 420                 return retval;
 421         }
 422
 423         current->mm->start_stack =
 424                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 425 #ifdef __alpha__
 426         regs->gp = ex.a_gpvalue;
 427 #endif
 428         start_thread(regs, ex.a_entry, current->mm->start_stack);
 429         if (unlikely(current->ptrace & PT_PTRACED)) {
 430                 if (current->ptrace & PT_TRACE_EXEC)
 431                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 432                 else
 433                         send_sig(SIGTRAP, current, 0);
 434         }
 435         return 0;
 436 }
 437
 438 static int load_aout_library(struct file *file)
 439 {
 440         struct inode * inode;
 441         unsigned long bss, start_addr, len;
 442         unsigned long error;
 443         int retval;
 444         struct exec ex;
 445
 446         inode = file->f_dentry->d_inode;
 447
 448         retval = -ENOEXEC;
 449         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 450         if (error != sizeof(ex))
 451                 goto out;
 452
 453         /* We come in here for the regular a.out style of shared libraries */
 454         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 455             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 456             i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 457                 goto out;
 458         }
 459
 460         if (N_FLAGS(ex))
 461                 goto out;
 462
 463         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 464            this off to get the starting address for the page */
 465
 466         start_addr =  ex.a_entry & 0xfffff000;
 467
 468         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 469                 static unsigned long error_time;
 470                 loff_t pos = N_TXTOFF(ex);
 471
 472                 if ((jiffies-error_time) > 5*HZ)
 473                 {
 474                         printk(KERN_WARNING
 475                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 476                                file->f_dentry->d_name.name);
 477                         error_time = jiffies;
 478                 }
 479
 480                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 481
 482                 file->f_op->read(file, (char *)start_addr,
 483                         ex.a_text + ex.a_data, &pos);
 484                 flush_icache_range((unsigned long) start_addr,
 485                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 486
 487                 retval = 0;
 488                 goto out;
 489         }
 490         /* Now use mmap to map the library into memory. */
 491         down_write(&current->mm->mmap_sem);
 492         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 493                         PROT_READ | PROT_WRITE | PROT_EXEC,
 494                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 495                         N_TXTOFF(ex));
 496         up_write(&current->mm->mmap_sem);
 497         retval = error;
 498         if (error != start_addr)
 499                 goto out;
 500
 501         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 502         bss = ex.a_text + ex.a_data + ex.a_bss;
 503         if (bss > len) {
 504                 error = do_brk(start_addr + len, bss - len);
 505                 retval = error;
 506                 if (error != start_addr + len)
 507                         goto out;
 508         }
 509         retval = 0;
 510 out:
 511         return retval;
 512 }
 513
 514 static int __init init_aout_binfmt(void)
 515 {
 516         return register_binfmt(&aout_format);
 517 }
 518
 519 static void __exit exit_aout_binfmt(void)
 520 {
 521         unregister_binfmt(&aout_format);
 522 }
 523
 524 module_init(init_aout_binfmt);
 525 module_exit(exit_aout_binfmt);
 526 MODULE_LICENSE("GPL");