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         savesegment(fs, fs);
  89         dump->regs.fs = fs;
  90         savesegment(gs, gs);
  91         dump->regs.gs = gs;
  92         dump->regs.orig_ax = regs->orig_ax;
  93         dump->regs.ip = regs->ip;
  94         dump->regs.cs = regs->cs;
  95         dump->regs.flags = regs->flags;
  96         dump->regs.sp = regs->sp;
  97         dump->regs.ss = regs->ss;
  98
  99 #if 1 /* FIXME */
 100         dump->u_fpvalid = 0;
 101 #else
 102         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 103 #endif
 104 }
 105
 106 #endif
 107
 108 static struct linux_binfmt aout_format = {
 109         .module         = THIS_MODULE,
 110         .load_binary    = load_aout_binary,
 111         .load_shlib     = load_aout_library,
 112 #ifdef CORE_DUMP
 113         .core_dump      = aout_core_dump,
 114 #endif
 115         .min_coredump   = PAGE_SIZE
 116 };
 117
 118 static void set_brk(unsigned long start, unsigned long end)
 119 {
 120         start = PAGE_ALIGN(start);
 121         end = PAGE_ALIGN(end);
 122         if (end <= start)
 123                 return;
 124         down_write(&current->mm->mmap_sem);
 125         do_brk(start, end - start);
 126         up_write(&current->mm->mmap_sem);
 127 }
 128
 129 #ifdef CORE_DUMP
 130 /*
 131  * These are the only things you should do on a core-file: use only these
 132  * macros to write out all the necessary info.
 133  */
 134
 135 static int dump_write(struct file *file, const void *addr, int nr)
 136 {
 137         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 138 }
 139
 140 #define DUMP_WRITE(addr, nr)                         \
 141         if (!dump_write(file, (void *)(addr), (nr))) \
 142                 goto end_coredump;
 143
 144 #define DUMP_SEEK(offset)                                               \
 145         if (file->f_op->llseek) {                                       \
 146                 if (file->f_op->llseek(file, (offset), 0) != (offset))  \
 147                         goto end_coredump;                              \
 148         } else                                                          \
 149                 file->f_pos = (offset)
 150
 151 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 152 #define START_STACK(u)  (u.start_stack)
 153
 154 /*
 155  * Routine writes a core dump image in the current directory.
 156  * Currently only a stub-function.
 157  *
 158  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 159  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 160  * field, which also makes sure the core-dumps won't be recursive if the
 161  * dumping of the process results in another error..
 162  */
 163
 164 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 165                           unsigned long limit)
 166 {
 167         mm_segment_t fs;
 168         int has_dumped = 0;
 169         unsigned long dump_start, dump_size;
 170         struct user32 dump;
 171
 172         fs = get_fs();
 173         set_fs(KERNEL_DS);
 174         has_dumped = 1;
 175         current->flags |= PF_DUMPCORE;
 176         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 177         dump.u_ar0 = offsetof(struct user32, regs);
 178         dump.signal = signr;
 179         dump_thread32(regs, &dump);
 180
 181         /*
 182          * If the size of the dump file exceeds the rlimit, then see
 183          * what would happen if we wrote the stack, but not the data
 184          * area.
 185          */
 186         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 187                 dump.u_dsize = 0;
 188
 189         /* Make sure we have enough room to write the stack and data areas. */
 190         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 191                 dump.u_ssize = 0;
 192
 193         /* make sure we actually have a data and stack area to dump */
 194         set_fs(USER_DS);
 195         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 196                        dump.u_dsize << PAGE_SHIFT))
 197                 dump.u_dsize = 0;
 198         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 199                        dump.u_ssize << PAGE_SHIFT))
 200                 dump.u_ssize = 0;
 201
 202         set_fs(KERNEL_DS);
 203         /* struct user */
 204         DUMP_WRITE(&dump, sizeof(dump));
 205         /* Now dump all of the user data.  Include malloced stuff as well */
 206         DUMP_SEEK(PAGE_SIZE);
 207         /* now we start writing out the user space info */
 208         set_fs(USER_DS);
 209         /* Dump the data area */
 210         if (dump.u_dsize != 0) {
 211                 dump_start = START_DATA(dump);
 212                 dump_size = dump.u_dsize << PAGE_SHIFT;
 213                 DUMP_WRITE(dump_start, dump_size);
 214         }
 215         /* Now prepare to dump the stack area */
 216         if (dump.u_ssize != 0) {
 217                 dump_start = START_STACK(dump);
 218                 dump_size = dump.u_ssize << PAGE_SHIFT;
 219                 DUMP_WRITE(dump_start, dump_size);
 220         }
 221         /*
 222          * Finally dump the task struct.  Not be used by gdb, but
 223          * could be useful
 224          */
 225         set_fs(KERNEL_DS);
 226         DUMP_WRITE(current, sizeof(*current));
 227 end_coredump:
 228         set_fs(fs);
 229         return has_dumped;
 230 }
 231 #endif
 232
 233 /*
 234  * create_aout_tables() parses the env- and arg-strings in new user
 235  * memory and creates the pointer tables from them, and puts their
 236  * addresses on the "stack", returning the new stack pointer value.
 237  */
 238 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 239 {
 240         u32 __user *argv, *envp, *sp;
 241         int argc = bprm->argc, envc = bprm->envc;
 242
 243         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 244         sp -= envc+1;
 245         envp = sp;
 246         sp -= argc+1;
 247         argv = sp;
 248         put_user((unsigned long) envp, --sp);
 249         put_user((unsigned long) argv, --sp);
 250         put_user(argc, --sp);
 251         current->mm->arg_start = (unsigned long) p;
 252         while (argc-- > 0) {
 253                 char c;
 254
 255                 put_user((u32)(unsigned long)p, argv++);
 256                 do {
 257                         get_user(c, p++);
 258                 } while (c);
 259         }
 260         put_user(0, argv);
 261         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 262         while (envc-- > 0) {
 263                 char c;
 264
 265                 put_user((u32)(unsigned long)p, envp++);
 266                 do {
 267                         get_user(c, p++);
 268                 } while (c);
 269         }
 270         put_user(0, envp);
 271         current->mm->env_end = (unsigned long) p;
 272         return sp;
 273 }
 274
 275 /*
 276  * These are the functions used to load a.out style executables and shared
 277  * libraries.  There is no binary dependent code anywhere else.
 278  */
 279 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 280 {
 281         unsigned long error, fd_offset, rlim;
 282         struct exec ex;
 283         int retval;
 284
 285         ex = *((struct exec *) bprm->buf);              /* exec-header */
 286         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 287              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 288             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 289             i_size_read(bprm->file->f_path.dentry->d_inode) <
 290             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 291                 return -ENOEXEC;
 292         }
 293
 294         fd_offset = N_TXTOFF(ex);
 295
 296         /* Check initial limits. This avoids letting people circumvent
 297          * size limits imposed on them by creating programs with large
 298          * arrays in the data or bss.
 299          */
 300         rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 301         if (rlim >= RLIM_INFINITY)
 302                 rlim = ~0;
 303         if (ex.a_data + ex.a_bss > rlim)
 304                 return -ENOMEM;
 305
 306         /* Flush all traces of the currently running executable */
 307         retval = flush_old_exec(bprm);
 308         if (retval)
 309                 return retval;
 310
 311         /* OK, This is the point of no return */
 312         set_personality(PER_LINUX);
 313         set_thread_flag(TIF_IA32);
 314
 315         setup_new_exec(bprm);
 316
 317         regs->cs = __USER32_CS;
 318         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 319                 regs->r13 = regs->r14 = regs->r15 = 0;
 320
 321         current->mm->end_code = ex.a_text +
 322                 (current->mm->start_code = N_TXTADDR(ex));
 323         current->mm->end_data = ex.a_data +
 324                 (current->mm->start_data = N_DATADDR(ex));
 325         current->mm->brk = ex.a_bss +
 326                 (current->mm->start_brk = N_BSSADDR(ex));
 327         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 328         current->mm->cached_hole_size = 0;
 329
 330         current->mm->mmap = NULL;
 331         install_exec_creds(bprm);
 332         current->flags &= ~PF_FORKNOEXEC;
 333
 334         if (N_MAGIC(ex) == OMAGIC) {
 335                 unsigned long text_addr, map_size;
 336                 loff_t pos;
 337
 338                 text_addr = N_TXTADDR(ex);
 339
 340                 pos = 32;
 341                 map_size = ex.a_text+ex.a_data;
 342
 343                 down_write(&current->mm->mmap_sem);
 344                 error = do_brk(text_addr & PAGE_MASK, map_size);
 345                 up_write(&current->mm->mmap_sem);
 346
 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,
 353                          (char __user *)text_addr,
 354                           ex.a_text+ex.a_data, &pos);
 355                 if ((signed long)error < 0) {
 356                         send_sig(SIGKILL, current, 0);
 357                         return error;
 358                 }
 359
 360                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 361         } else {
 362 #ifdef WARN_OLD
 363                 static unsigned long error_time, error_time2;
 364                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 365                     (N_MAGIC(ex) != NMAGIC) &&
 366                                 time_after(jiffies, error_time2 + 5*HZ)) {
 367                         printk(KERN_NOTICE "executable not page aligned\n");
 368                         error_time2 = jiffies;
 369                 }
 370
 371                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 372                             time_after(jiffies, error_time + 5*HZ)) {
 373                         printk(KERN_WARNING
 374                                "fd_offset is not page aligned. Please convert "
 375                                "program: %s\n",
 376                                bprm->file->f_path.dentry->d_name.name);
 377                         error_time = jiffies;
 378                 }
 379 #endif
 380
 381                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 382                         loff_t pos = fd_offset;
 383
 384                         down_write(&current->mm->mmap_sem);
 385                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 386                         up_write(&current->mm->mmap_sem);
 387                         bprm->file->f_op->read(bprm->file,
 388                                         (char __user *)N_TXTADDR(ex),
 389                                         ex.a_text+ex.a_data, &pos);
 390                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 391                                            (unsigned long) N_TXTADDR(ex) +
 392                                            ex.a_text+ex.a_data);
 393                         goto beyond_if;
 394                 }
 395
 396                 down_write(&current->mm->mmap_sem);
 397                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 398                                 PROT_READ | PROT_EXEC,
 399                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 400                                 MAP_EXECUTABLE | MAP_32BIT,
 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 |
 413                                 MAP_EXECUTABLE | MAP_32BIT,
 414                                 fd_offset + ex.a_text);
 415                 up_write(&current->mm->mmap_sem);
 416                 if (error != N_DATADDR(ex)) {
 417                         send_sig(SIGKILL, current, 0);
 418                         return error;
 419                 }
 420         }
 421 beyond_if:
 422         set_binfmt(&aout_format);
 423
 424         set_brk(current->mm->start_brk, current->mm->brk);
 425
 426         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 427         if (retval < 0) {
 428                 /* Someone check-me: is this error path enough? */
 429                 send_sig(SIGKILL, current, 0);
 430                 return retval;
 431         }
 432
 433         current->mm->start_stack =
 434                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 435         /* start thread */
 436         loadsegment(fs, 0);
 437         loadsegment(ds, __USER32_DS);
 438         loadsegment(es, __USER32_DS);
 439         load_gs_index(0);
 440         (regs)->ip = ex.a_entry;
 441         (regs)->sp = current->mm->start_stack;
 442         (regs)->flags = 0x200;
 443         (regs)->cs = __USER32_CS;
 444         (regs)->ss = __USER32_DS;
 445         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 446         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 447         set_fs(USER_DS);
 448         return 0;
 449 }
 450
 451 static int load_aout_library(struct file *file)
 452 {
 453         struct inode *inode;
 454         unsigned long bss, start_addr, len, error;
 455         int retval;
 456         struct exec ex;
 457
 458         inode = file->f_path.dentry->d_inode;
 459
 460         retval = -ENOEXEC;
 461         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 462         if (error != sizeof(ex))
 463                 goto out;
 464
 465         /* We come in here for the regular a.out style of shared libraries */
 466         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 467             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 468             i_size_read(inode) <
 469             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 470                 goto out;
 471         }
 472
 473         if (N_FLAGS(ex))
 474                 goto out;
 475
 476         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 477            this off to get the starting address for the page */
 478
 479         start_addr =  ex.a_entry & 0xfffff000;
 480
 481         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 482                 loff_t pos = N_TXTOFF(ex);
 483
 484 #ifdef WARN_OLD
 485                 static unsigned long error_time;
 486                 if (time_after(jiffies, error_time + 5*HZ)) {
 487                         printk(KERN_WARNING
 488                                "N_TXTOFF is not page aligned. Please convert "
 489                                "library: %s\n",
 490                                file->f_path.dentry->d_name.name);
 491                         error_time = jiffies;
 492                 }
 493 #endif
 494                 down_write(&current->mm->mmap_sem);
 495                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 496                 up_write(&current->mm->mmap_sem);
 497
 498                 file->f_op->read(file, (char __user *)start_addr,
 499                         ex.a_text + ex.a_data, &pos);
 500                 flush_icache_range((unsigned long) start_addr,
 501                                    (unsigned long) start_addr + ex.a_text +
 502                                    ex.a_data);
 503
 504                 retval = 0;
 505                 goto out;
 506         }
 507         /* Now use mmap to map the library into memory. */
 508         down_write(&current->mm->mmap_sem);
 509         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 510                         PROT_READ | PROT_WRITE | PROT_EXEC,
 511                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 512                         N_TXTOFF(ex));
 513         up_write(&current->mm->mmap_sem);
 514         retval = error;
 515         if (error != start_addr)
 516                 goto out;
 517
 518         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 519         bss = ex.a_text + ex.a_data + ex.a_bss;
 520         if (bss > len) {
 521                 down_write(&current->mm->mmap_sem);
 522                 error = do_brk(start_addr + len, bss - len);
 523                 up_write(&current->mm->mmap_sem);
 524                 retval = error;
 525                 if (error != start_addr + len)
 526                         goto out;
 527         }
 528         retval = 0;
 529 out:
 530         return retval;
 531 }
 532
 533 static int __init init_aout_binfmt(void)
 534 {
 535         return register_binfmt(&aout_format);
 536 }
 537
 538 static void __exit exit_aout_binfmt(void)
 539 {
 540         unregister_binfmt(&aout_format);
 541 }
 542
 543 module_init(init_aout_binfmt);
 544 module_exit(exit_aout_binfmt);
 545 MODULE_LICENSE("GPL");