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/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
  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 #define BAD_ADDR(x)     ((unsigned long)(x) >= TASK_SIZE)
  43
  44 static int set_brk(unsigned long start, unsigned long end)
  45 {
  46         start = PAGE_ALIGN(start);
  47         end = PAGE_ALIGN(end);
  48         if (end > start) {
  49                 unsigned long addr;
  50                 down_write(&current->mm->mmap_sem);
  51                 addr = do_brk(start, end - start);
  52                 up_write(&current->mm->mmap_sem);
  53                 if (BAD_ADDR(addr))
  54                         return addr;
  55         }
  56         return 0;
  57 }
  58
  59 /*
  60  * These are the only things you should do on a core-file: use only these
  61  * macros to write out all the necessary info.
  62  */
  63
  64 static int dump_write(struct file *file, const void *addr, int nr)
  65 {
  66         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  67 }
  68
  69 #define DUMP_WRITE(addr, nr)    \
  70         if (!dump_write(file, (void *)(addr), (nr))) \
  71                 goto end_coredump;
  72
  73 #define DUMP_SEEK(offset) \
  74 if (file->f_op->llseek) { \
  75         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  76                 goto end_coredump; \
  77 } else file->f_pos = (offset)
  78
  79 /*
  80  * Routine writes a core dump image in the current directory.
  81  * Currently only a stub-function.
  82  *
  83  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  84  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
  85  * field, which also makes sure the core-dumps won't be recursive if the
  86  * dumping of the process results in another error..
  87  */
  88
  89 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
  90 {
  91         mm_segment_t fs;
  92         int has_dumped = 0;
  93         unsigned long dump_start, dump_size;
  94         struct user dump;
  95 #if defined(__alpha__)
  96 #       define START_DATA(u)    (u.start_data)
  97 #elif defined(__arm__)
  98 #       define START_DATA(u)    ((u.u_tsize << PAGE_SHIFT) + u.start_code)
  99 #elif defined(__sparc__)
 100 #       define START_DATA(u)    (u.u_tsize)
 101 #elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
 102 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 103 #endif
 104 #ifdef __sparc__
 105 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
 106 #else
 107 #       define START_STACK(u)   (u.start_stack)
 108 #endif
 109
 110         fs = get_fs();
 111         set_fs(KERNEL_DS);
 112         has_dumped = 1;
 113         current->flags |= PF_DUMPCORE;
 114         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 115 #ifndef __sparc__
 116         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 117 #endif
 118         dump.signal = signr;
 119         dump_thread(regs, &dump);
 120
 121 /* If the size of the dump file exceeds the rlimit, then see what would happen
 122    if we wrote the stack, but not the data area.  */
 123 #ifdef __sparc__
 124         if ((dump.u_dsize+dump.u_ssize) >
 125             current->rlim[RLIMIT_CORE].rlim_cur)
 126                 dump.u_dsize = 0;
 127 #else
 128         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 129             current->rlim[RLIMIT_CORE].rlim_cur)
 130                 dump.u_dsize = 0;
 131 #endif
 132
 133 /* Make sure we have enough room to write the stack and data areas. */
 134 #ifdef __sparc__
 135         if ((dump.u_ssize) >
 136             current->rlim[RLIMIT_CORE].rlim_cur)
 137                 dump.u_ssize = 0;
 138 #else
 139         if ((dump.u_ssize+1) * PAGE_SIZE >
 140             current->rlim[RLIMIT_CORE].rlim_cur)
 141                 dump.u_ssize = 0;
 142 #endif
 143
 144 /* make sure we actually have a data and stack area to dump */
 145         set_fs(USER_DS);
 146 #ifdef __sparc__
 147         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 148                 dump.u_dsize = 0;
 149         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 150                 dump.u_ssize = 0;
 151 #else
 152         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 153                 dump.u_dsize = 0;
 154         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 155                 dump.u_ssize = 0;
 156 #endif
 157
 158         set_fs(KERNEL_DS);
 159 /* struct user */
 160         DUMP_WRITE(&dump,sizeof(dump));
 161 /* Now dump all of the user data.  Include malloced stuff as well */
 162 #ifndef __sparc__
 163         DUMP_SEEK(PAGE_SIZE);
 164 #endif
 165 /* now we start writing out the user space info */
 166         set_fs(USER_DS);
 167 /* Dump the data area */
 168         if (dump.u_dsize != 0) {
 169                 dump_start = START_DATA(dump);
 170 #ifdef __sparc__
 171                 dump_size = dump.u_dsize;
 172 #else
 173                 dump_size = dump.u_dsize << PAGE_SHIFT;
 174 #endif
 175                 DUMP_WRITE(dump_start,dump_size);
 176         }
 177 /* Now prepare to dump the stack area */
 178         if (dump.u_ssize != 0) {
 179                 dump_start = START_STACK(dump);
 180 #ifdef __sparc__
 181                 dump_size = dump.u_ssize;
 182 #else
 183                 dump_size = dump.u_ssize << PAGE_SHIFT;
 184 #endif
 185                 DUMP_WRITE(dump_start,dump_size);
 186         }
 187 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 188         set_fs(KERNEL_DS);
 189         DUMP_WRITE(current,sizeof(*current));
 190 end_coredump:
 191         set_fs(fs);
 192         return has_dumped;
 193 }
 194
 195 /*
 196  * create_aout_tables() parses the env- and arg-strings in new user
 197  * memory and creates the pointer tables from them, and puts their
 198  * addresses on the "stack", returning the new stack pointer value.
 199  */
 200 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 201 {
 202         char **argv, **envp;
 203         unsigned long * sp;
 204         int argc = bprm->argc;
 205         int envc = bprm->envc;
 206
 207         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 208 #ifdef __sparc__
 209         /* This imposes the proper stack alignment for a new process. */
 210         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 211         if ((envc+argc+3)&1) --sp;
 212 #endif
 213 #ifdef __alpha__
 214 /* whee.. test-programs are so much fun. */
 215         put_user(0, --sp);
 216         put_user(0, --sp);
 217         if (bprm->loader) {
 218                 put_user(0, --sp);
 219                 put_user(0x3eb, --sp);
 220                 put_user(bprm->loader, --sp);
 221                 put_user(0x3ea, --sp);
 222         }
 223         put_user(bprm->exec, --sp);
 224         put_user(0x3e9, --sp);
 225 #endif
 226         sp -= envc+1;
 227         envp = (char **) sp;
 228         sp -= argc+1;
 229         argv = (char **) sp;
 230 #if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
 231         put_user((unsigned long) envp,--sp);
 232         put_user((unsigned long) argv,--sp);
 233 #endif
 234         put_user(argc,--sp);
 235         current->mm->arg_start = (unsigned long) p;
 236         while (argc-->0) {
 237                 char c;
 238                 put_user(p,argv++);
 239                 do {
 240                         get_user(c,p++);
 241                 } while (c);
 242         }
 243         put_user(NULL,argv);
 244         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 245         while (envc-->0) {
 246                 char c;
 247                 put_user(p,envp++);
 248                 do {
 249                         get_user(c,p++);
 250                 } while (c);
 251         }
 252         put_user(NULL,envp);
 253         current->mm->env_end = (unsigned long) p;
 254         return sp;
 255 }
 256
 257 /*
 258  * These are the functions used to load a.out style executables and shared
 259  * libraries.  There is no binary dependent code anywhere else.
 260  */
 261
 262 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 263 {
 264         struct exec ex;
 265         unsigned long error;
 266         unsigned long fd_offset;
 267         unsigned long rlim;
 268         int retval;
 269
 270         ex = *((struct exec *) bprm->buf);              /* exec-header */
 271         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 272              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 273             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 274             bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 275                 return -ENOEXEC;
 276         }
 277
 278         fd_offset = N_TXTOFF(ex);
 279
 280         /* Check initial limits. This avoids letting people circumvent
 281          * size limits imposed on them by creating programs with large
 282          * arrays in the data or bss.
 283          */
 284         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 285         if (rlim >= RLIM_INFINITY)
 286                 rlim = ~0;
 287         if (ex.a_data + ex.a_bss > rlim)
 288                 return -ENOMEM;
 289
 290         /* Flush all traces of the currently running executable */
 291         retval = flush_old_exec(bprm);
 292         if (retval)
 293                 return retval;
 294
 295         /* OK, This is the point of no return */
 296 #if defined(__alpha__)
 297         SET_AOUT_PERSONALITY(bprm, ex);
 298 #elif defined(__sparc__)
 299         set_personality(PER_SUNOS);
 300 #if !defined(__sparc_v9__)
 301         memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
 302 #endif
 303 #else
 304         set_personality(PER_LINUX);
 305 #endif
 306
 307         current->mm->end_code = ex.a_text +
 308                 (current->mm->start_code = N_TXTADDR(ex));
 309         current->mm->end_data = ex.a_data +
 310                 (current->mm->start_data = N_DATADDR(ex));
 311         current->mm->brk = ex.a_bss +
 312                 (current->mm->start_brk = N_BSSADDR(ex));
 313
 314         current->mm->rss = 0;
 315         current->mm->mmap = NULL;
 316         compute_creds(bprm);
 317         current->flags &= ~PF_FORKNOEXEC;
 318 #ifdef __sparc__
 319         if (N_MAGIC(ex) == NMAGIC) {
 320                 loff_t pos = fd_offset;
 321                 /* Fuck me plenty... */
 322                 /* <AOL></AOL> */
 323                 down_write(&current->mm->mmap_sem);
 324                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 325                 up_write(&current->mm->mmap_sem);
 326                 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
 327                           ex.a_text, &pos);
 328                 down_write(&current->mm->mmap_sem);
 329                 error = do_brk(N_DATADDR(ex), ex.a_data);
 330                 up_write(&current->mm->mmap_sem);
 331                 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
 332                           ex.a_data, &pos);
 333                 goto beyond_if;
 334         }
 335 #endif
 336
 337         if (N_MAGIC(ex) == OMAGIC) {
 338                 unsigned long text_addr, map_size;
 339                 loff_t pos;
 340
 341                 text_addr = N_TXTADDR(ex);
 342
 343 #if defined(__alpha__) || defined(__sparc__)
 344                 pos = fd_offset;
 345                 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
 346 #else
 347                 pos = 32;
 348                 map_size = ex.a_text+ex.a_data;
 349 #endif
 350                 down_write(&current->mm->mmap_sem);
 351                 error = do_brk(text_addr & PAGE_MASK, map_size);
 352                 up_write(&current->mm->mmap_sem);
 353                 if (error != (text_addr & PAGE_MASK)) {
 354                         send_sig(SIGKILL, current, 0);
 355                         return error;
 356                 }
 357
 358                 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
 359                           ex.a_text+ex.a_data, &pos);
 360                 if ((signed long)error < 0) {
 361                         send_sig(SIGKILL, current, 0);
 362                         return error;
 363                 }
 364
 365                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 366         } else {
 367                 static unsigned long error_time, error_time2;
 368                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 369                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 370                 {
 371                         printk(KERN_NOTICE "executable not page aligned\n");
 372                         error_time2 = jiffies;
 373                 }
 374
 375                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 376                     (jiffies-error_time) > 5*HZ)
 377                 {
 378                         printk(KERN_WARNING
 379                                "fd_offset is not page aligned. Please convert program: %s\n",
 380                                bprm->file->f_dentry->d_name.name);
 381                         error_time = jiffies;
 382                 }
 383
 384                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 385                         loff_t pos = fd_offset;
 386                         down_write(&current->mm->mmap_sem);
 387                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 388                         up_write(&current->mm->mmap_sem);
 389                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 390                                         ex.a_text+ex.a_data, &pos);
 391                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 392                                            (unsigned long) N_TXTADDR(ex) +
 393                                            ex.a_text+ex.a_data);
 394                         goto beyond_if;
 395                 }
 396
 397                 down_write(&current->mm->mmap_sem);
 398                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 399                         PROT_READ | PROT_EXEC,
 400                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 401                         fd_offset);
 402                 up_write(&current->mm->mmap_sem);
 403
 404                 if (error != N_TXTADDR(ex)) {
 405                         send_sig(SIGKILL, current, 0);
 406                         return error;
 407                 }
 408
 409                 down_write(&current->mm->mmap_sem);
 410                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 411                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 412                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 413                                 fd_offset + ex.a_text);
 414                 up_write(&current->mm->mmap_sem);
 415                 if (error != N_DATADDR(ex)) {
 416                         send_sig(SIGKILL, current, 0);
 417                         return error;
 418                 }
 419         }
 420 beyond_if:
 421         set_binfmt(&aout_format);
 422
 423         retval = set_brk(current->mm->start_brk, current->mm->brk);
 424         if (retval < 0) {
 425                 send_sig(SIGKILL, current, 0);
 426                 return retval;
 427         }
 428
 429         retval = setup_arg_pages(bprm);
 430         if (retval < 0) {
 431                 /* Someone check-me: is this error path enough? */
 432                 send_sig(SIGKILL, current, 0);
 433                 return retval;
 434         }
 435
 436         current->mm->start_stack =
 437                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 438 #ifdef __alpha__
 439         regs->gp = ex.a_gpvalue;
 440 #endif
 441         start_thread(regs, ex.a_entry, current->mm->start_stack);
 442         if (current->ptrace & PT_PTRACED)
 443                 send_sig(SIGTRAP, current, 0);
 444         return 0;
 445 }
 446
 447 static int load_aout_library(struct file *file)
 448 {
 449         struct inode * inode;
 450         unsigned long bss, start_addr, len;
 451         unsigned long error;
 452         int retval;
 453         struct exec ex;
 454
 455         inode = file->f_dentry->d_inode;
 456
 457         retval = -ENOEXEC;
 458         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 459         if (error != sizeof(ex))
 460                 goto out;
 461
 462         /* We come in here for the regular a.out style of shared libraries */
 463         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 464             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 465             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 466                 goto out;
 467         }
 468
 469         if (N_FLAGS(ex))
 470                 goto out;
 471
 472         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 473            this off to get the starting address for the page */
 474
 475         start_addr =  ex.a_entry & 0xfffff000;
 476
 477         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 478                 static unsigned long error_time;
 479                 loff_t pos = N_TXTOFF(ex);
 480
 481                 if ((jiffies-error_time) > 5*HZ)
 482                 {
 483                         printk(KERN_WARNING
 484                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 485                                file->f_dentry->d_name.name);
 486                         error_time = jiffies;
 487                 }
 488
 489                 down_write(&current->mm->mmap_sem);
 490                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 491                 up_write(&current->mm->mmap_sem);
 492
 493                 file->f_op->read(file, (char *)start_addr,
 494                         ex.a_text + ex.a_data, &pos);
 495                 flush_icache_range((unsigned long) start_addr,
 496                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 497
 498                 retval = 0;
 499                 goto out;
 500         }
 501         /* Now use mmap to map the library into memory. */
 502         down_write(&current->mm->mmap_sem);
 503         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 504                         PROT_READ | PROT_WRITE | PROT_EXEC,
 505                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 506                         N_TXTOFF(ex));
 507         up_write(&current->mm->mmap_sem);
 508         retval = error;
 509         if (error != start_addr)
 510                 goto out;
 511
 512         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 513         bss = ex.a_text + ex.a_data + ex.a_bss;
 514         if (bss > len) {
 515                 down_write(&current->mm->mmap_sem);
 516                 error = do_brk(start_addr + len, bss - len);
 517                 up_write(&current->mm->mmap_sem);
 518
 519                 retval = error;
 520                 if (error != start_addr + len)
 521                         goto out;
 522         }
 523         retval = 0;
 524 out:
 525         return retval;
 526 }
 527
 528 static int __init init_aout_binfmt(void)
 529 {
 530         return register_binfmt(&aout_format);
 531 }
 532
 533 static void __exit exit_aout_binfmt(void)
 534 {
 535         unregister_binfmt(&aout_format);
 536 }
 537
 538 EXPORT_NO_SYMBOLS;
 539
 540 module_init(init_aout_binfmt);
 541 module_exit(exit_aout_binfmt);
 542 MODULE_LICENSE("GPL");