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 #include <linux/jiffies.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/user32.h>
  35 #include <asm/ia32.h>
  36
  37 #undef WARN_OLD
  38 #undef CORE_DUMP /* probably broken */
  39
  40 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
  41 static int load_aout_library(struct file *);
  42
  43 #ifdef CORE_DUMP
  44 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
  45                           unsigned long limit);
  46
  47 /*
  48  * fill in the user structure for a core dump..
  49  */
  50 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  51 {
  52         u32 fs, gs;
  53
  54 /* changed the size calculations - should hopefully work better. lbt */
  55         dump->magic = CMAGIC;
  56         dump->start_code = 0;
  57         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  58         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  59         dump->u_dsize = ((unsigned long)
  60                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  61         dump->u_dsize -= dump->u_tsize;
  62         dump->u_ssize = 0;
  63         dump->u_debugreg[0] = current->thread.debugreg0;
  64         dump->u_debugreg[1] = current->thread.debugreg1;
  65         dump->u_debugreg[2] = current->thread.debugreg2;
  66         dump->u_debugreg[3] = current->thread.debugreg3;
  67         dump->u_debugreg[4] = 0;
  68         dump->u_debugreg[5] = 0;
  69         dump->u_debugreg[6] = current->thread.debugreg6;
  70         dump->u_debugreg[7] = current->thread.debugreg7;
  71
  72         if (dump->start_stack < 0xc0000000) {
  73                 unsigned long tmp;
  74
  75                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  76                 dump->u_ssize = tmp >> PAGE_SHIFT;
  77         }
  78
  79         dump->regs.bx = regs->bx;
  80         dump->regs.cx = regs->cx;
  81         dump->regs.dx = regs->dx;
  82         dump->regs.si = regs->si;
  83         dump->regs.di = regs->di;
  84         dump->regs.bp = regs->bp;
  85         dump->regs.ax = regs->ax;
  86         dump->regs.ds = current->thread.ds;
  87         dump->regs.es = current->thread.es;
  88         asm("movl %%fs,%0" : "=r" (fs)); dump->regs.fs = fs;
  89         asm("movl %%gs,%0" : "=r" (gs)); dump->regs.gs = gs;
  90         dump->regs.orig_ax = regs->orig_ax;
  91         dump->regs.ip = regs->ip;
  92         dump->regs.cs = regs->cs;
  93         dump->regs.flags = regs->flags;
  94         dump->regs.sp = regs->sp;
  95         dump->regs.ss = regs->ss;
  96
  97 #if 1 /* FIXME */
  98         dump->u_fpvalid = 0;
  99 #else
 100         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 101 #endif
 102 }
 103
 104 #endif
 105
 106 static struct linux_binfmt aout_format = {
 107         .module         = THIS_MODULE,
 108         .load_binary    = load_aout_binary,
 109         .load_shlib     = load_aout_library,
 110 #ifdef CORE_DUMP
 111         .core_dump      = aout_core_dump,
 112 #endif
 113         .min_coredump   = PAGE_SIZE
 114 };
 115
 116 static void set_brk(unsigned long start, unsigned long end)
 117 {
 118         start = PAGE_ALIGN(start);
 119         end = PAGE_ALIGN(end);
 120         if (end <= start)
 121                 return;
 122         down_write(&current->mm->mmap_sem);
 123         do_brk(start, end - start);
 124         up_write(&current->mm->mmap_sem);
 125 }
 126
 127 #ifdef CORE_DUMP
 128 /*
 129  * These are the only things you should do on a core-file: use only these
 130  * macros to write out all the necessary info.
 131  */
 132
 133 static int dump_write(struct file *file, const void *addr, int nr)
 134 {
 135         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 136 }
 137
 138 #define DUMP_WRITE(addr, nr)                         \
 139         if (!dump_write(file, (void *)(addr), (nr))) \
 140                 goto end_coredump;
 141
 142 #define DUMP_SEEK(offset)                                               \
 143         if (file->f_op->llseek) {                                       \
 144                 if (file->f_op->llseek(file, (offset), 0) != (offset))  \
 145                         goto end_coredump;                              \
 146         } else                                                          \
 147                 file->f_pos = (offset)
 148
 149 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 150 #define START_STACK(u)  (u.start_stack)
 151
 152 /*
 153  * Routine writes a core dump image in the current directory.
 154  * Currently only a stub-function.
 155  *
 156  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 157  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 158  * field, which also makes sure the core-dumps won't be recursive if the
 159  * dumping of the process results in another error..
 160  */
 161
 162 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 163                           unsigned long limit)
 164 {
 165         mm_segment_t fs;
 166         int has_dumped = 0;
 167         unsigned long dump_start, dump_size;
 168         struct user32 dump;
 169
 170         fs = get_fs();
 171         set_fs(KERNEL_DS);
 172         has_dumped = 1;
 173         current->flags |= PF_DUMPCORE;
 174         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 175         dump.u_ar0 = offsetof(struct user32, regs);
 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) &&
 363                                 time_after(jiffies, error_time2 + 5*HZ)) {
 364                         printk(KERN_NOTICE "executable not page aligned\n");
 365                         error_time2 = jiffies;
 366                 }
 367
 368                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 369                             time_after(jiffies, error_time + 5*HZ)) {
 370                         printk(KERN_WARNING
 371                                "fd_offset is not page aligned. Please convert "
 372                                "program: %s\n",
 373                                bprm->file->f_path.dentry->d_name.name);
 374                         error_time = jiffies;
 375                 }
 376 #endif
 377
 378                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 379                         loff_t pos = fd_offset;
 380
 381                         down_write(&current->mm->mmap_sem);
 382                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 383                         up_write(&current->mm->mmap_sem);
 384                         bprm->file->f_op->read(bprm->file,
 385                                         (char __user *)N_TXTADDR(ex),
 386                                         ex.a_text+ex.a_data, &pos);
 387                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 388                                            (unsigned long) N_TXTADDR(ex) +
 389                                            ex.a_text+ex.a_data);
 390                         goto beyond_if;
 391                 }
 392
 393                 down_write(&current->mm->mmap_sem);
 394                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 395                                 PROT_READ | PROT_EXEC,
 396                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 397                                 MAP_EXECUTABLE | MAP_32BIT,
 398                                 fd_offset);
 399                 up_write(&current->mm->mmap_sem);
 400
 401                 if (error != N_TXTADDR(ex)) {
 402                         send_sig(SIGKILL, current, 0);
 403                         return error;
 404                 }
 405
 406                 down_write(&current->mm->mmap_sem);
 407                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 408                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 409                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 410                                 MAP_EXECUTABLE | MAP_32BIT,
 411                                 fd_offset + ex.a_text);
 412                 up_write(&current->mm->mmap_sem);
 413                 if (error != N_DATADDR(ex)) {
 414                         send_sig(SIGKILL, current, 0);
 415                         return error;
 416                 }
 417         }
 418 beyond_if:
 419         set_binfmt(&aout_format);
 420
 421         set_brk(current->mm->start_brk, current->mm->brk);
 422
 423         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 424         if (retval < 0) {
 425                 /* Someone check-me: is this error path enough? */
 426                 send_sig(SIGKILL, current, 0);
 427                 return retval;
 428         }
 429
 430         current->mm->start_stack =
 431                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 432         /* start thread */
 433         asm volatile("movl %0,%%fs" :: "r" (0)); \
 434         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 435         load_gs_index(0);
 436         (regs)->ip = ex.a_entry;
 437         (regs)->sp = current->mm->start_stack;
 438         (regs)->flags = 0x200;
 439         (regs)->cs = __USER32_CS;
 440         (regs)->ss = __USER32_DS;
 441         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 442         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 443         set_fs(USER_DS);
 444         if (unlikely(current->ptrace & PT_PTRACED)) {
 445                 if (current->ptrace & PT_TRACE_EXEC)
 446                         ptrace_notify((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 447                 else
 448                         send_sig(SIGTRAP, current, 0);
 449         }
 450         return 0;
 451 }
 452
 453 static int load_aout_library(struct file *file)
 454 {
 455         struct inode *inode;
 456         unsigned long bss, start_addr, len, error;
 457         int retval;
 458         struct exec ex;
 459
 460         inode = file->f_path.dentry->d_inode;
 461
 462         retval = -ENOEXEC;
 463         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 464         if (error != sizeof(ex))
 465                 goto out;
 466
 467         /* We come in here for the regular a.out style of shared libraries */
 468         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 469             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 470             i_size_read(inode) <
 471             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 472                 goto out;
 473         }
 474
 475         if (N_FLAGS(ex))
 476                 goto out;
 477
 478         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 479            this off to get the starting address for the page */
 480
 481         start_addr =  ex.a_entry & 0xfffff000;
 482
 483         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 484                 loff_t pos = N_TXTOFF(ex);
 485
 486 #ifdef WARN_OLD
 487                 static unsigned long error_time;
 488                 if (time_after(jiffies, error_time + 5*HZ)) {
 489                         printk(KERN_WARNING
 490                                "N_TXTOFF is not page aligned. Please convert "
 491                                "library: %s\n",
 492                                file->f_path.dentry->d_name.name);
 493                         error_time = jiffies;
 494                 }
 495 #endif
 496                 down_write(&current->mm->mmap_sem);
 497                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 498                 up_write(&current->mm->mmap_sem);
 499
 500                 file->f_op->read(file, (char __user *)start_addr,
 501                         ex.a_text + ex.a_data, &pos);
 502                 flush_icache_range((unsigned long) start_addr,
 503                                    (unsigned long) start_addr + ex.a_text +
 504                                    ex.a_data);
 505
 506                 retval = 0;
 507                 goto out;
 508         }
 509         /* Now use mmap to map the library into memory. */
 510         down_write(&current->mm->mmap_sem);
 511         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 512                         PROT_READ | PROT_WRITE | PROT_EXEC,
 513                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 514                         N_TXTOFF(ex));
 515         up_write(&current->mm->mmap_sem);
 516         retval = error;
 517         if (error != start_addr)
 518                 goto out;
 519
 520         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 521         bss = ex.a_text + ex.a_data + ex.a_bss;
 522         if (bss > len) {
 523                 down_write(&current->mm->mmap_sem);
 524                 error = do_brk(start_addr + len, bss - len);
 525                 up_write(&current->mm->mmap_sem);
 526                 retval = error;
 527                 if (error != start_addr + len)
 528                         goto out;
 529         }
 530         retval = 0;
 531 out:
 532         return retval;
 533 }
 534
 535 static int __init init_aout_binfmt(void)
 536 {
 537         return register_binfmt(&aout_format);
 538 }
 539
 540 static void __exit exit_aout_binfmt(void)
 541 {
 542         unregister_binfmt(&aout_format);
 543 }
 544
 545 module_init(init_aout_binfmt);
 546 module_exit(exit_aout_binfmt);
 547 MODULE_LICENSE("GPL");