arch/x86/ia32/ia32_aout.c

   1 /*
   2  *  a.out loader for x86-64
   3  *
   4  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
   5  *  Hacked together by Andi Kleen
   6  */
   7
   8 #include <linux/module.h>
   9
  10 #include <linux/time.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/mman.h>
  14 #include <linux/a.out.h>
  15 #include <linux/errno.h>
  16 #include <linux/signal.h>
  17 #include <linux/string.h>
  18 #include <linux/fs.h>
  19 #include <linux/file.h>
  20 #include <linux/stat.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/user.h>
  24 #include <linux/slab.h>
  25 #include <linux/binfmts.h>
  26 #include <linux/personality.h>
  27 #include <linux/init.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgalloc.h>
  32 #include <asm/cacheflush.h>
  33 #include <asm/user32.h>
  34 #include <asm/ia32.h>
  35
  36 #undef WARN_OLD
  37 #undef CORE_DUMP /* probably broken */
  38
  39 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
  40 static int load_aout_library(struct file *);
  41
  42 #ifdef CORE_DUMP
  43 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
  44                           unsigned long limit);
  45
  46 /*
  47  * fill in the user structure for a core dump..
  48  */
  49 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  50 {
  51         u32 fs, gs;
  52
  53 /* changed the size calculations - should hopefully work better. lbt */
  54         dump->magic = CMAGIC;
  55         dump->start_code = 0;
  56         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  57         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  58         dump->u_dsize = ((unsigned long)
  59                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  60         dump->u_dsize -= dump->u_tsize;
  61         dump->u_ssize = 0;
  62         dump->u_debugreg[0] = current->thread.debugreg0;
  63         dump->u_debugreg[1] = current->thread.debugreg1;
  64         dump->u_debugreg[2] = current->thread.debugreg2;
  65         dump->u_debugreg[3] = current->thread.debugreg3;
  66         dump->u_debugreg[4] = 0;
  67         dump->u_debugreg[5] = 0;
  68         dump->u_debugreg[6] = current->thread.debugreg6;
  69         dump->u_debugreg[7] = current->thread.debugreg7;
  70
  71         if (dump->start_stack < 0xc0000000) {
  72                 unsigned long tmp;
  73
  74                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  75                 dump->u_ssize = tmp >> PAGE_SHIFT;
  76         }
  77
  78         dump->regs.bx = regs->bx;
  79         dump->regs.cx = regs->cx;
  80         dump->regs.dx = regs->dx;
  81         dump->regs.si = regs->si;
  82         dump->regs.di = regs->di;
  83         dump->regs.bp = regs->bp;
  84         dump->regs.ax = regs->ax;
  85         dump->regs.ds = current->thread.ds;
  86         dump->regs.es = current->thread.es;
  87         asm("movl %%fs,%0" : "=r" (fs)); dump->regs.fs = fs;
  88         asm("movl %%gs,%0" : "=r" (gs)); dump->regs.gs = gs;
  89         dump->regs.orig_ax = regs->orig_ax;
  90         dump->regs.ip = regs->ip;
  91         dump->regs.cs = regs->cs;
  92         dump->regs.flags = regs->flags;
  93         dump->regs.sp = regs->sp;
  94         dump->regs.ss = regs->ss;
  95
  96 #if 1 /* FIXME */
  97         dump->u_fpvalid = 0;
  98 #else
  99         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 100 #endif
 101 }
 102
 103 #endif
 104
 105 static struct linux_binfmt aout_format = {
 106         .module         = THIS_MODULE,
 107         .load_binary    = load_aout_binary,
 108         .load_shlib     = load_aout_library,
 109 #ifdef CORE_DUMP
 110         .core_dump      = aout_core_dump,
 111 #endif
 112         .min_coredump   = PAGE_SIZE
 113 };
 114
 115 static void set_brk(unsigned long start, unsigned long end)
 116 {
 117         start = PAGE_ALIGN(start);
 118         end = PAGE_ALIGN(end);
 119         if (end <= start)
 120                 return;
 121         down_write(&current->mm->mmap_sem);
 122         do_brk(start, end - start);
 123         up_write(&current->mm->mmap_sem);
 124 }
 125
 126 #ifdef CORE_DUMP
 127 /*
 128  * These are the only things you should do on a core-file: use only these
 129  * macros to write out all the necessary info.
 130  */
 131
 132 static int dump_write(struct file *file, const void *addr, int nr)
 133 {
 134         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 135 }
 136
 137 #define DUMP_WRITE(addr, nr)                         \
 138         if (!dump_write(file, (void *)(addr), (nr))) \
 139                 goto end_coredump;
 140
 141 #define DUMP_SEEK(offset)                                               \
 142         if (file->f_op->llseek) {                                       \
 143                 if (file->f_op->llseek(file, (offset), 0) != (offset))  \
 144                         goto end_coredump;                              \
 145         } else                                                          \
 146                 file->f_pos = (offset)
 147
 148 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 149 #define START_STACK(u)  (u.start_stack)
 150
 151 /*
 152  * Routine writes a core dump image in the current directory.
 153  * Currently only a stub-function.
 154  *
 155  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 156  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 157  * field, which also makes sure the core-dumps won't be recursive if the
 158  * dumping of the process results in another error..
 159  */
 160
 161 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 162                           unsigned long limit)
 163 {
 164         mm_segment_t fs;
 165         int has_dumped = 0;
 166         unsigned long dump_start, dump_size;
 167         struct user32 dump;
 168
 169         fs = get_fs();
 170         set_fs(KERNEL_DS);
 171         has_dumped = 1;
 172         current->flags |= PF_DUMPCORE;
 173         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 174         dump.u_ar0 = (u32)(((unsigned long)(&dump.regs)) -
 175                            ((unsigned long)(&dump)));
 176         dump.signal = signr;
 177         dump_thread32(regs, &dump);
 178
 179         /*
 180          * If the size of the dump file exceeds the rlimit, then see
 181          * what would happen if we wrote the stack, but not the data
 182          * area.
 183          */
 184         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 185                 dump.u_dsize = 0;
 186
 187         /* Make sure we have enough room to write the stack and data areas. */
 188         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 189                 dump.u_ssize = 0;
 190
 191         /* make sure we actually have a data and stack area to dump */
 192         set_fs(USER_DS);
 193         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 194                        dump.u_dsize << PAGE_SHIFT))
 195                 dump.u_dsize = 0;
 196         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 197                        dump.u_ssize << PAGE_SHIFT))
 198                 dump.u_ssize = 0;
 199
 200         set_fs(KERNEL_DS);
 201         /* struct user */
 202         DUMP_WRITE(&dump, sizeof(dump));
 203         /* Now dump all of the user data.  Include malloced stuff as well */
 204         DUMP_SEEK(PAGE_SIZE);
 205         /* now we start writing out the user space info */
 206         set_fs(USER_DS);
 207         /* Dump the data area */
 208         if (dump.u_dsize != 0) {
 209                 dump_start = START_DATA(dump);
 210                 dump_size = dump.u_dsize << PAGE_SHIFT;
 211                 DUMP_WRITE(dump_start, dump_size);
 212         }
 213         /* Now prepare to dump the stack area */
 214         if (dump.u_ssize != 0) {
 215                 dump_start = START_STACK(dump);
 216                 dump_size = dump.u_ssize << PAGE_SHIFT;
 217                 DUMP_WRITE(dump_start, dump_size);
 218         }
 219         /*
 220          * Finally dump the task struct.  Not be used by gdb, but
 221          * could be useful
 222          */
 223         set_fs(KERNEL_DS);
 224         DUMP_WRITE(current, sizeof(*current));
 225 end_coredump:
 226         set_fs(fs);
 227         return has_dumped;
 228 }
 229 #endif
 230
 231 /*
 232  * create_aout_tables() parses the env- and arg-strings in new user
 233  * memory and creates the pointer tables from them, and puts their
 234  * addresses on the "stack", returning the new stack pointer value.
 235  */
 236 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 237 {
 238         u32 __user *argv, *envp, *sp;
 239         int argc = bprm->argc, envc = bprm->envc;
 240
 241         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 242         sp -= envc+1;
 243         envp = sp;
 244         sp -= argc+1;
 245         argv = sp;
 246         put_user((unsigned long) envp, --sp);
 247         put_user((unsigned long) argv, --sp);
 248         put_user(argc, --sp);
 249         current->mm->arg_start = (unsigned long) p;
 250         while (argc-- > 0) {
 251                 char c;
 252
 253                 put_user((u32)(unsigned long)p, argv++);
 254                 do {
 255                         get_user(c, p++);
 256                 } while (c);
 257         }
 258         put_user(0, argv);
 259         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 260         while (envc-- > 0) {
 261                 char c;
 262
 263                 put_user((u32)(unsigned long)p, envp++);
 264                 do {
 265                         get_user(c, p++);
 266                 } while (c);
 267         }
 268         put_user(0, envp);
 269         current->mm->env_end = (unsigned long) p;
 270         return sp;
 271 }
 272
 273 /*
 274  * These are the functions used to load a.out style executables and shared
 275  * libraries.  There is no binary dependent code anywhere else.
 276  */
 277 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 278 {
 279         unsigned long error, fd_offset, rlim;
 280         struct exec ex;
 281         int retval;
 282
 283         ex = *((struct exec *) bprm->buf);              /* exec-header */
 284         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 285              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 286             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 287             i_size_read(bprm->file->f_path.dentry->d_inode) <
 288             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 289                 return -ENOEXEC;
 290         }
 291
 292         fd_offset = N_TXTOFF(ex);
 293
 294         /* Check initial limits. This avoids letting people circumvent
 295          * size limits imposed on them by creating programs with large
 296          * arrays in the data or bss.
 297          */
 298         rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 299         if (rlim >= RLIM_INFINITY)
 300                 rlim = ~0;
 301         if (ex.a_data + ex.a_bss > rlim)
 302                 return -ENOMEM;
 303
 304         /* Flush all traces of the currently running executable */
 305         retval = flush_old_exec(bprm);
 306         if (retval)
 307                 return retval;
 308
 309         regs->cs = __USER32_CS;
 310         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 311                 regs->r13 = regs->r14 = regs->r15 = 0;
 312
 313         /* OK, This is the point of no return */
 314         set_personality(PER_LINUX);
 315         set_thread_flag(TIF_IA32);
 316         clear_thread_flag(TIF_ABI_PENDING);
 317
 318         current->mm->end_code = ex.a_text +
 319                 (current->mm->start_code = N_TXTADDR(ex));
 320         current->mm->end_data = ex.a_data +
 321                 (current->mm->start_data = N_DATADDR(ex));
 322         current->mm->brk = ex.a_bss +
 323                 (current->mm->start_brk = N_BSSADDR(ex));
 324         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 325         current->mm->cached_hole_size = 0;
 326
 327         current->mm->mmap = NULL;
 328         compute_creds(bprm);
 329         current->flags &= ~PF_FORKNOEXEC;
 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                 pos = 32;
 338                 map_size = ex.a_text+ex.a_data;
 339
 340                 down_write(&current->mm->mmap_sem);
 341                 error = do_brk(text_addr & PAGE_MASK, map_size);
 342                 up_write(&current->mm->mmap_sem);
 343
 344                 if (error != (text_addr & PAGE_MASK)) {
 345                         send_sig(SIGKILL, current, 0);
 346                         return error;
 347                 }
 348
 349                 error = bprm->file->f_op->read(bprm->file,
 350                          (char __user *)text_addr,
 351                           ex.a_text+ex.a_data, &pos);
 352                 if ((signed long)error < 0) {
 353                         send_sig(SIGKILL, current, 0);
 354                         return error;
 355                 }
 356
 357                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 358         } else {
 359 #ifdef WARN_OLD
 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                         printk(KERN_NOTICE "executable not page aligned\n");
 364                         error_time2 = jiffies;
 365                 }
 366
 367                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 368                     (jiffies - error_time) > 5*HZ) {
 369                         printk(KERN_WARNING
 370                                "fd_offset is not page aligned. Please convert "
 371                                "program: %s\n",
 372                                bprm->file->f_path.dentry->d_name.name);
 373                         error_time = jiffies;
 374                 }
 375 #endif
 376
 377                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 378                         loff_t pos = fd_offset;
 379
 380                         down_write(&current->mm->mmap_sem);
 381                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 382                         up_write(&current->mm->mmap_sem);
 383                         bprm->file->f_op->read(bprm->file,
 384                                         (char __user *)N_TXTADDR(ex),
 385                                         ex.a_text+ex.a_data, &pos);
 386                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 387                                            (unsigned long) N_TXTADDR(ex) +
 388                                            ex.a_text+ex.a_data);
 389                         goto beyond_if;
 390                 }
 391
 392                 down_write(&current->mm->mmap_sem);
 393                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 394                                 PROT_READ | PROT_EXEC,
 395                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 396                                 MAP_EXECUTABLE | MAP_32BIT,
 397                                 fd_offset);
 398                 up_write(&current->mm->mmap_sem);
 399
 400                 if (error != N_TXTADDR(ex)) {
 401                         send_sig(SIGKILL, current, 0);
 402                         return error;
 403                 }
 404
 405                 down_write(&current->mm->mmap_sem);
 406                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 407                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 408                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 409                                 MAP_EXECUTABLE | MAP_32BIT,
 410                                 fd_offset + ex.a_text);
 411                 up_write(&current->mm->mmap_sem);
 412                 if (error != N_DATADDR(ex)) {
 413                         send_sig(SIGKILL, current, 0);
 414                         return error;
 415                 }
 416         }
 417 beyond_if:
 418         set_binfmt(&aout_format);
 419
 420         set_brk(current->mm->start_brk, current->mm->brk);
 421
 422         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 423         if (retval < 0) {
 424                 /* Someone check-me: is this error path enough? */
 425                 send_sig(SIGKILL, current, 0);
 426                 return retval;
 427         }
 428
 429         current->mm->start_stack =
 430                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 431         /* start thread */
 432         asm volatile("movl %0,%%fs" :: "r" (0)); \
 433         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 434         load_gs_index(0);
 435         (regs)->ip = ex.a_entry;
 436         (regs)->sp = current->mm->start_stack;
 437         (regs)->flags = 0x200;
 438         (regs)->cs = __USER32_CS;
 439         (regs)->ss = __USER32_DS;
 440         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 441         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 442         set_fs(USER_DS);
 443         if (unlikely(current->ptrace & PT_PTRACED)) {
 444                 if (current->ptrace & PT_TRACE_EXEC)
 445                         ptrace_notify((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 446                 else
 447                         send_sig(SIGTRAP, current, 0);
 448         }
 449         return 0;
 450 }
 451
 452 static int load_aout_library(struct file *file)
 453 {
 454         struct inode *inode;
 455         unsigned long bss, start_addr, len, error;
 456         int retval;
 457         struct exec ex;
 458
 459         inode = file->f_path.dentry->d_inode;
 460
 461         retval = -ENOEXEC;
 462         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 463         if (error != sizeof(ex))
 464                 goto out;
 465
 466         /* We come in here for the regular a.out style of shared libraries */
 467         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 468             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 469             i_size_read(inode) <
 470             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 471                 goto out;
 472         }
 473
 474         if (N_FLAGS(ex))
 475                 goto out;
 476
 477         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 478            this off to get the starting address for the page */
 479
 480         start_addr =  ex.a_entry & 0xfffff000;
 481
 482         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 483                 loff_t pos = N_TXTOFF(ex);
 484
 485 #ifdef WARN_OLD
 486                 static unsigned long error_time;
 487                 if ((jiffies-error_time) > 5*HZ) {
 488                         printk(KERN_WARNING
 489                                "N_TXTOFF is not page aligned. Please convert "
 490                                "library: %s\n",
 491                                file->f_path.dentry->d_name.name);
 492                         error_time = jiffies;
 493                 }
 494 #endif
 495                 down_write(&current->mm->mmap_sem);
 496                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 497                 up_write(&current->mm->mmap_sem);
 498
 499                 file->f_op->read(file, (char __user *)start_addr,
 500                         ex.a_text + ex.a_data, &pos);
 501                 flush_icache_range((unsigned long) start_addr,
 502                                    (unsigned long) start_addr + ex.a_text +
 503                                    ex.a_data);
 504
 505                 retval = 0;
 506                 goto out;
 507         }
 508         /* Now use mmap to map the library into memory. */
 509         down_write(&current->mm->mmap_sem);
 510         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 511                         PROT_READ | PROT_WRITE | PROT_EXEC,
 512                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 513                         N_TXTOFF(ex));
 514         up_write(&current->mm->mmap_sem);
 515         retval = error;
 516         if (error != start_addr)
 517                 goto out;
 518
 519         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 520         bss = ex.a_text + ex.a_data + ex.a_bss;
 521         if (bss > len) {
 522                 down_write(&current->mm->mmap_sem);
 523                 error = do_brk(start_addr + len, bss - len);
 524                 up_write(&current->mm->mmap_sem);
 525                 retval = error;
 526                 if (error != start_addr + len)
 527                         goto out;
 528         }
 529         retval = 0;
 530 out:
 531         return retval;
 532 }
 533
 534 static int __init init_aout_binfmt(void)
 535 {
 536         return register_binfmt(&aout_format);
 537 }
 538
 539 static void __exit exit_aout_binfmt(void)
 540 {
 541         unregister_binfmt(&aout_format);
 542 }
 543
 544 module_init(init_aout_binfmt);
 545 module_exit(exit_aout_binfmt);
 546 MODULE_LICENSE("GPL");