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 #include <linux/ptrace.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgalloc.h>
  32 #include <asm/cacheflush.h>
  33
  34 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  35 static int load_aout_library(struct file*);
  36 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
  37
  38 extern void dump_thread(struct pt_regs *, struct user *);
  39
  40 static struct linux_binfmt aout_format = {
  41         .module         = THIS_MODULE,
  42         .load_binary    = load_aout_binary,
  43         .load_shlib     = load_aout_library,
  44         .core_dump      = aout_core_dump,
  45         .min_coredump   = 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->mm->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 int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
  88 {
  89         mm_segment_t fs;
  90         int has_dumped = 0;
  91         unsigned long dump_start, dump_size;
  92         struct user dump;
  93 #if defined(__alpha__)
  94 #       define START_DATA(u)    (u.start_data)
  95 #elif defined(__arm__)
  96 #       define START_DATA(u)    ((u.u_tsize << PAGE_SHIFT) + u.start_code)
  97 #elif defined(__sparc__)
  98 #       define START_DATA(u)    (u.u_tsize)
  99 #elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
 100 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 101 #endif
 102 #ifdef __sparc__
 103 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
 104 #else
 105 #       define START_STACK(u)   (u.start_stack)
 106 #endif
 107
 108         fs = get_fs();
 109         set_fs(KERNEL_DS);
 110         has_dumped = 1;
 111         current->flags |= PF_DUMPCORE;
 112         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 113 #ifndef __sparc__
 114         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 115 #endif
 116         dump.signal = signr;
 117         dump_thread(regs, &dump);
 118
 119 /* If the size of the dump file exceeds the rlimit, then see what would happen
 120    if we wrote the stack, but not the data area.  */
 121 #ifdef __sparc__
 122         if ((dump.u_dsize+dump.u_ssize) >
 123             current->rlim[RLIMIT_CORE].rlim_cur)
 124                 dump.u_dsize = 0;
 125 #else
 126         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 127             current->rlim[RLIMIT_CORE].rlim_cur)
 128                 dump.u_dsize = 0;
 129 #endif
 130
 131 /* Make sure we have enough room to write the stack and data areas. */
 132 #ifdef __sparc__
 133         if ((dump.u_ssize) >
 134             current->rlim[RLIMIT_CORE].rlim_cur)
 135                 dump.u_ssize = 0;
 136 #else
 137         if ((dump.u_ssize+1) * PAGE_SIZE >
 138             current->rlim[RLIMIT_CORE].rlim_cur)
 139                 dump.u_ssize = 0;
 140 #endif
 141
 142 /* make sure we actually have a data and stack area to dump */
 143         set_fs(USER_DS);
 144 #ifdef __sparc__
 145         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 146                 dump.u_dsize = 0;
 147         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 148                 dump.u_ssize = 0;
 149 #else
 150         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 151                 dump.u_dsize = 0;
 152         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 153                 dump.u_ssize = 0;
 154 #endif
 155
 156         set_fs(KERNEL_DS);
 157 /* struct user */
 158         DUMP_WRITE(&dump,sizeof(dump));
 159 /* Now dump all of the user data.  Include malloced stuff as well */
 160 #ifndef __sparc__
 161         DUMP_SEEK(PAGE_SIZE);
 162 #endif
 163 /* now we start writing out the user space info */
 164         set_fs(USER_DS);
 165 /* Dump the data area */
 166         if (dump.u_dsize != 0) {
 167                 dump_start = START_DATA(dump);
 168 #ifdef __sparc__
 169                 dump_size = dump.u_dsize;
 170 #else
 171                 dump_size = dump.u_dsize << PAGE_SHIFT;
 172 #endif
 173                 DUMP_WRITE(dump_start,dump_size);
 174         }
 175 /* Now prepare to dump the stack area */
 176         if (dump.u_ssize != 0) {
 177                 dump_start = START_STACK(dump);
 178 #ifdef __sparc__
 179                 dump_size = dump.u_ssize;
 180 #else
 181                 dump_size = dump.u_ssize << PAGE_SHIFT;
 182 #endif
 183                 DUMP_WRITE(dump_start,dump_size);
 184         }
 185 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 186         set_fs(KERNEL_DS);
 187         DUMP_WRITE(current,sizeof(*current));
 188 end_coredump:
 189         set_fs(fs);
 190         return has_dumped;
 191 }
 192
 193 /*
 194  * create_aout_tables() parses the env- and arg-strings in new user
 195  * memory and creates the pointer tables from them, and puts their
 196  * addresses on the "stack", returning the new stack pointer value.
 197  */
 198 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 199 {
 200         char **argv, **envp;
 201         unsigned long * sp;
 202         int argc = bprm->argc;
 203         int envc = bprm->envc;
 204
 205         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 206 #ifdef __sparc__
 207         /* This imposes the proper stack alignment for a new process. */
 208         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 209         if ((envc+argc+3)&1) --sp;
 210 #endif
 211 #ifdef __alpha__
 212 /* whee.. test-programs are so much fun. */
 213         put_user(0, --sp);
 214         put_user(0, --sp);
 215         if (bprm->loader) {
 216                 put_user(0, --sp);
 217                 put_user(0x3eb, --sp);
 218                 put_user(bprm->loader, --sp);
 219                 put_user(0x3ea, --sp);
 220         }
 221         put_user(bprm->exec, --sp);
 222         put_user(0x3e9, --sp);
 223 #endif
 224         sp -= envc+1;
 225         envp = (char **) sp;
 226         sp -= argc+1;
 227         argv = (char **) sp;
 228 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
 229         put_user((unsigned long) envp,--sp);
 230         put_user((unsigned long) argv,--sp);
 231 #endif
 232         put_user(argc,--sp);
 233         current->mm->arg_start = (unsigned long) p;
 234         while (argc-->0) {
 235                 char c;
 236                 put_user(p,argv++);
 237                 do {
 238                         get_user(c,p++);
 239                 } while (c);
 240         }
 241         put_user(NULL,argv);
 242         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 243         while (envc-->0) {
 244                 char c;
 245                 put_user(p,envp++);
 246                 do {
 247                         get_user(c,p++);
 248                 } while (c);
 249         }
 250         put_user(NULL,envp);
 251         current->mm->env_end = (unsigned long) p;
 252         return sp;
 253 }
 254
 255 /*
 256  * These are the functions used to load a.out style executables and shared
 257  * libraries.  There is no binary dependent code anywhere else.
 258  */
 259
 260 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 261 {
 262         struct exec ex;
 263         unsigned long error;
 264         unsigned long fd_offset;
 265         unsigned long rlim;
 266         int retval;
 267
 268         ex = *((struct exec *) bprm->buf);              /* exec-header */
 269         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 270              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 271             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 272             i_size_read(bprm->file->f_dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 273                 return -ENOEXEC;
 274         }
 275
 276         fd_offset = N_TXTOFF(ex);
 277
 278         /* Check initial limits. This avoids letting people circumvent
 279          * size limits imposed on them by creating programs with large
 280          * arrays in the data or bss.
 281          */
 282         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 283         if (rlim >= RLIM_INFINITY)
 284                 rlim = ~0;
 285         if (ex.a_data + ex.a_bss > rlim)
 286                 return -ENOMEM;
 287
 288         /* Flush all traces of the currently running executable */
 289         retval = flush_old_exec(bprm);
 290         if (retval)
 291                 return retval;
 292
 293         /* OK, This is the point of no return */
 294 #if defined(__alpha__)
 295         SET_AOUT_PERSONALITY(bprm, ex);
 296 #elif defined(__sparc__)
 297         set_personality(PER_SUNOS);
 298 #if !defined(__sparc_v9__)
 299         memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
 300 #endif
 301 #else
 302         set_personality(PER_LINUX);
 303 #endif
 304
 305         current->mm->end_code = ex.a_text +
 306                 (current->mm->start_code = N_TXTADDR(ex));
 307         current->mm->end_data = ex.a_data +
 308                 (current->mm->start_data = N_DATADDR(ex));
 309         current->mm->brk = ex.a_bss +
 310                 (current->mm->start_brk = N_BSSADDR(ex));
 311         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 312
 313         current->mm->rss = 0;
 314         current->mm->mmap = NULL;
 315         compute_creds(bprm);
 316         current->flags &= ~PF_FORKNOEXEC;
 317 #ifdef __sparc__
 318         if (N_MAGIC(ex) == NMAGIC) {
 319                 loff_t pos = fd_offset;
 320                 /* Fuck me plenty... */
 321                 /* <AOL></AOL> */
 322                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 323                 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
 324                           ex.a_text, &pos);
 325                 error = do_brk(N_DATADDR(ex), ex.a_data);
 326                 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
 327                           ex.a_data, &pos);
 328                 goto beyond_if;
 329         }
 330 #endif
 331
 332         if (N_MAGIC(ex) == OMAGIC) {
 333                 unsigned long text_addr, map_size;
 334                 loff_t pos;
 335
 336                 text_addr = N_TXTADDR(ex);
 337
 338 #if defined(__alpha__) || defined(__sparc__)
 339                 pos = fd_offset;
 340                 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
 341 #else
 342                 pos = 32;
 343                 map_size = ex.a_text+ex.a_data;
 344 #endif
 345
 346                 error = do_brk(text_addr & PAGE_MASK, map_size);
 347                 if (error != (text_addr & PAGE_MASK)) {
 348                         send_sig(SIGKILL, current, 0);
 349                         return error;
 350                 }
 351
 352                 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
 353                           ex.a_text+ex.a_data, &pos);
 354                 if ((signed long)error < 0) {
 355                         send_sig(SIGKILL, current, 0);
 356                         return error;
 357                 }
 358
 359                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 360         } else {
 361                 static unsigned long error_time, error_time2;
 362                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 363                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 364                 {
 365                         printk(KERN_NOTICE "executable not page aligned\n");
 366                         error_time2 = jiffies;
 367                 }
 368
 369                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 370                     (jiffies-error_time) > 5*HZ)
 371                 {
 372                         printk(KERN_WARNING
 373                                "fd_offset is not page aligned. Please convert program: %s\n",
 374                                bprm->file->f_dentry->d_name.name);
 375                         error_time = jiffies;
 376                 }
 377
 378                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 379                         loff_t pos = fd_offset;
 380                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 381                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 382                                         ex.a_text+ex.a_data, &pos);
 383                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 384                                            (unsigned long) N_TXTADDR(ex) +
 385                                            ex.a_text+ex.a_data);
 386                         goto beyond_if;
 387                 }
 388
 389                 down_write(&current->mm->mmap_sem);
 390                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 391                         PROT_READ | PROT_EXEC,
 392                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 393                         fd_offset);
 394                 up_write(&current->mm->mmap_sem);
 395
 396                 if (error != N_TXTADDR(ex)) {
 397                         send_sig(SIGKILL, current, 0);
 398                         return error;
 399                 }
 400
 401                 down_write(&current->mm->mmap_sem);
 402                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 403                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 404                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 405                                 fd_offset + ex.a_text);
 406                 up_write(&current->mm->mmap_sem);
 407                 if (error != N_DATADDR(ex)) {
 408                         send_sig(SIGKILL, current, 0);
 409                         return error;
 410                 }
 411         }
 412 beyond_if:
 413         set_binfmt(&aout_format);
 414
 415         set_brk(current->mm->start_brk, current->mm->brk);
 416
 417         retval = setup_arg_pages(bprm);
 418         if (retval < 0) {
 419                 /* Someone check-me: is this error path enough? */
 420                 send_sig(SIGKILL, current, 0);
 421                 return retval;
 422         }
 423
 424         current->mm->start_stack =
 425                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 426 #ifdef __alpha__
 427         regs->gp = ex.a_gpvalue;
 428 #endif
 429         start_thread(regs, ex.a_entry, current->mm->start_stack);
 430         if (unlikely(current->ptrace & PT_PTRACED)) {
 431                 if (current->ptrace & PT_TRACE_EXEC)
 432                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 433                 else
 434                         send_sig(SIGTRAP, current, 0);
 435         }
 436         return 0;
 437 }
 438
 439 static int load_aout_library(struct file *file)
 440 {
 441         struct inode * inode;
 442         unsigned long bss, start_addr, len;
 443         unsigned long error;
 444         int retval;
 445         struct exec ex;
 446
 447         inode = file->f_dentry->d_inode;
 448
 449         retval = -ENOEXEC;
 450         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 451         if (error != sizeof(ex))
 452                 goto out;
 453
 454         /* We come in here for the regular a.out style of shared libraries */
 455         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 456             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 457             i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 458                 goto out;
 459         }
 460
 461         if (N_FLAGS(ex))
 462                 goto out;
 463
 464         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 465            this off to get the starting address for the page */
 466
 467         start_addr =  ex.a_entry & 0xfffff000;
 468
 469         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 470                 static unsigned long error_time;
 471                 loff_t pos = N_TXTOFF(ex);
 472
 473                 if ((jiffies-error_time) > 5*HZ)
 474                 {
 475                         printk(KERN_WARNING
 476                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 477                                file->f_dentry->d_name.name);
 478                         error_time = jiffies;
 479                 }
 480
 481                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 482
 483                 file->f_op->read(file, (char *)start_addr,
 484                         ex.a_text + ex.a_data, &pos);
 485                 flush_icache_range((unsigned long) start_addr,
 486                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 487
 488                 retval = 0;
 489                 goto out;
 490         }
 491         /* Now use mmap to map the library into memory. */
 492         down_write(&current->mm->mmap_sem);
 493         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 494                         PROT_READ | PROT_WRITE | PROT_EXEC,
 495                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 496                         N_TXTOFF(ex));
 497         up_write(&current->mm->mmap_sem);
 498         retval = error;
 499         if (error != start_addr)
 500                 goto out;
 501
 502         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 503         bss = ex.a_text + ex.a_data + ex.a_bss;
 504         if (bss > len) {
 505                 error = do_brk(start_addr + len, bss - len);
 506                 retval = error;
 507                 if (error != start_addr + len)
 508                         goto out;
 509         }
 510         retval = 0;
 511 out:
 512         return retval;
 513 }
 514
 515 static int __init init_aout_binfmt(void)
 516 {
 517         return register_binfmt(&aout_format);
 518 }
 519
 520 static void __exit exit_aout_binfmt(void)
 521 {
 522         unregister_binfmt(&aout_format);
 523 }
 524
 525 module_init(init_aout_binfmt);
 526 module_exit(exit_aout_binfmt);
 527 MODULE_LICENSE("GPL");