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 = (u32)(((unsigned long)(&dump.regs)) -
 176                            ((unsigned long)(&dump)));
 177         dump.signal = signr;
 178         dump_thread32(regs, &dump);
 179
 180         /*
 181          * If the size of the dump file exceeds the rlimit, then see
 182          * what would happen if we wrote the stack, but not the data
 183          * area.
 184          */
 185         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 186                 dump.u_dsize = 0;
 187
 188         /* Make sure we have enough room to write the stack and data areas. */
 189         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 190                 dump.u_ssize = 0;
 191
 192         /* make sure we actually have a data and stack area to dump */
 193         set_fs(USER_DS);
 194         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 195                        dump.u_dsize << PAGE_SHIFT))
 196                 dump.u_dsize = 0;
 197         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 198                        dump.u_ssize << PAGE_SHIFT))
 199                 dump.u_ssize = 0;
 200
 201         set_fs(KERNEL_DS);
 202         /* struct user */
 203         DUMP_WRITE(&dump, sizeof(dump));
 204         /* Now dump all of the user data.  Include malloced stuff as well */
 205         DUMP_SEEK(PAGE_SIZE);
 206         /* now we start writing out the user space info */
 207         set_fs(USER_DS);
 208         /* Dump the data area */
 209         if (dump.u_dsize != 0) {
 210                 dump_start = START_DATA(dump);
 211                 dump_size = dump.u_dsize << PAGE_SHIFT;
 212                 DUMP_WRITE(dump_start, dump_size);
 213         }
 214         /* Now prepare to dump the stack area */
 215         if (dump.u_ssize != 0) {
 216                 dump_start = START_STACK(dump);
 217                 dump_size = dump.u_ssize << PAGE_SHIFT;
 218                 DUMP_WRITE(dump_start, dump_size);
 219         }
 220         /*
 221          * Finally dump the task struct.  Not be used by gdb, but
 222          * could be useful
 223          */
 224         set_fs(KERNEL_DS);
 225         DUMP_WRITE(current, sizeof(*current));
 226 end_coredump:
 227         set_fs(fs);
 228         return has_dumped;
 229 }
 230 #endif
 231
 232 /*
 233  * create_aout_tables() parses the env- and arg-strings in new user
 234  * memory and creates the pointer tables from them, and puts their
 235  * addresses on the "stack", returning the new stack pointer value.
 236  */
 237 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 238 {
 239         u32 __user *argv, *envp, *sp;
 240         int argc = bprm->argc, envc = bprm->envc;
 241
 242         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 243         sp -= envc+1;
 244         envp = sp;
 245         sp -= argc+1;
 246         argv = sp;
 247         put_user((unsigned long) envp, --sp);
 248         put_user((unsigned long) argv, --sp);
 249         put_user(argc, --sp);
 250         current->mm->arg_start = (unsigned long) p;
 251         while (argc-- > 0) {
 252                 char c;
 253
 254                 put_user((u32)(unsigned long)p, argv++);
 255                 do {
 256                         get_user(c, p++);
 257                 } while (c);
 258         }
 259         put_user(0, argv);
 260         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 261         while (envc-- > 0) {
 262                 char c;
 263
 264                 put_user((u32)(unsigned long)p, envp++);
 265                 do {
 266                         get_user(c, p++);
 267                 } while (c);
 268         }
 269         put_user(0, envp);
 270         current->mm->env_end = (unsigned long) p;
 271         return sp;
 272 }
 273
 274 /*
 275  * These are the functions used to load a.out style executables and shared
 276  * libraries.  There is no binary dependent code anywhere else.
 277  */
 278 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 279 {
 280         unsigned long error, fd_offset, rlim;
 281         struct exec ex;
 282         int retval;
 283
 284         ex = *((struct exec *) bprm->buf);              /* exec-header */
 285         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 286              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 287             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 288             i_size_read(bprm->file->f_path.dentry->d_inode) <
 289             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 290                 return -ENOEXEC;
 291         }
 292
 293         fd_offset = N_TXTOFF(ex);
 294
 295         /* Check initial limits. This avoids letting people circumvent
 296          * size limits imposed on them by creating programs with large
 297          * arrays in the data or bss.
 298          */
 299         rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 300         if (rlim >= RLIM_INFINITY)
 301                 rlim = ~0;
 302         if (ex.a_data + ex.a_bss > rlim)
 303                 return -ENOMEM;
 304
 305         /* Flush all traces of the currently running executable */
 306         retval = flush_old_exec(bprm);
 307         if (retval)
 308                 return retval;
 309
 310         regs->cs = __USER32_CS;
 311         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 312                 regs->r13 = regs->r14 = regs->r15 = 0;
 313
 314         /* OK, This is the point of no return */
 315         set_personality(PER_LINUX);
 316         set_thread_flag(TIF_IA32);
 317         clear_thread_flag(TIF_ABI_PENDING);
 318
 319         current->mm->end_code = ex.a_text +
 320                 (current->mm->start_code = N_TXTADDR(ex));
 321         current->mm->end_data = ex.a_data +
 322                 (current->mm->start_data = N_DATADDR(ex));
 323         current->mm->brk = ex.a_bss +
 324                 (current->mm->start_brk = N_BSSADDR(ex));
 325         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 326         current->mm->cached_hole_size = 0;
 327
 328         current->mm->mmap = NULL;
 329         compute_creds(bprm);
 330         current->flags &= ~PF_FORKNOEXEC;
 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                 pos = 32;
 339                 map_size = ex.a_text+ex.a_data;
 340
 341                 down_write(&current->mm->mmap_sem);
 342                 error = do_brk(text_addr & PAGE_MASK, map_size);
 343                 up_write(&current->mm->mmap_sem);
 344
 345                 if (error != (text_addr & PAGE_MASK)) {
 346                         send_sig(SIGKILL, current, 0);
 347                         return error;
 348                 }
 349
 350                 error = bprm->file->f_op->read(bprm->file,
 351                          (char __user *)text_addr,
 352                           ex.a_text+ex.a_data, &pos);
 353                 if ((signed long)error < 0) {
 354                         send_sig(SIGKILL, current, 0);
 355                         return error;
 356                 }
 357
 358                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 359         } else {
 360 #ifdef WARN_OLD
 361                 static unsigned long error_time, error_time2;
 362                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 363                     (N_MAGIC(ex) != NMAGIC) &&
 364                                 time_after(jiffies, error_time2 + 5*HZ)) {
 365                         printk(KERN_NOTICE "executable not page aligned\n");
 366                         error_time2 = jiffies;
 367                 }
 368
 369                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 370                             time_after(jiffies, error_time + 5*HZ)) {
 371                         printk(KERN_WARNING
 372                                "fd_offset is not page aligned. Please convert "
 373                                "program: %s\n",
 374                                bprm->file->f_path.dentry->d_name.name);
 375                         error_time = jiffies;
 376                 }
 377 #endif
 378
 379                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 380                         loff_t pos = fd_offset;
 381
 382                         down_write(&current->mm->mmap_sem);
 383                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 384                         up_write(&current->mm->mmap_sem);
 385                         bprm->file->f_op->read(bprm->file,
 386                                         (char __user *)N_TXTADDR(ex),
 387                                         ex.a_text+ex.a_data, &pos);
 388                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 389                                            (unsigned long) N_TXTADDR(ex) +
 390                                            ex.a_text+ex.a_data);
 391                         goto beyond_if;
 392                 }
 393
 394                 down_write(&current->mm->mmap_sem);
 395                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 396                                 PROT_READ | PROT_EXEC,
 397                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 398                                 MAP_EXECUTABLE | MAP_32BIT,
 399                                 fd_offset);
 400                 up_write(&current->mm->mmap_sem);
 401
 402                 if (error != N_TXTADDR(ex)) {
 403                         send_sig(SIGKILL, current, 0);
 404                         return error;
 405                 }
 406
 407                 down_write(&current->mm->mmap_sem);
 408                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 409                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 410                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 411                                 MAP_EXECUTABLE | MAP_32BIT,
 412                                 fd_offset + ex.a_text);
 413                 up_write(&current->mm->mmap_sem);
 414                 if (error != N_DATADDR(ex)) {
 415                         send_sig(SIGKILL, current, 0);
 416                         return error;
 417                 }
 418         }
 419 beyond_if:
 420         set_binfmt(&aout_format);
 421
 422         set_brk(current->mm->start_brk, current->mm->brk);
 423
 424         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 425         if (retval < 0) {
 426                 /* Someone check-me: is this error path enough? */
 427                 send_sig(SIGKILL, current, 0);
 428                 return retval;
 429         }
 430
 431         current->mm->start_stack =
 432                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 433         /* start thread */
 434         asm volatile("movl %0,%%fs" :: "r" (0)); \
 435         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 436         load_gs_index(0);
 437         (regs)->ip = ex.a_entry;
 438         (regs)->sp = current->mm->start_stack;
 439         (regs)->flags = 0x200;
 440         (regs)->cs = __USER32_CS;
 441         (regs)->ss = __USER32_DS;
 442         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 443         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 444         set_fs(USER_DS);
 445         if (unlikely(current->ptrace & PT_PTRACED)) {
 446                 if (current->ptrace & PT_TRACE_EXEC)
 447                         ptrace_notify((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 448                 else
 449                         send_sig(SIGTRAP, current, 0);
 450         }
 451         return 0;
 452 }
 453
 454 static int load_aout_library(struct file *file)
 455 {
 456         struct inode *inode;
 457         unsigned long bss, start_addr, len, error;
 458         int retval;
 459         struct exec ex;
 460
 461         inode = file->f_path.dentry->d_inode;
 462
 463         retval = -ENOEXEC;
 464         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 465         if (error != sizeof(ex))
 466                 goto out;
 467
 468         /* We come in here for the regular a.out style of shared libraries */
 469         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 470             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 471             i_size_read(inode) <
 472             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 473                 goto out;
 474         }
 475
 476         if (N_FLAGS(ex))
 477                 goto out;
 478
 479         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 480            this off to get the starting address for the page */
 481
 482         start_addr =  ex.a_entry & 0xfffff000;
 483
 484         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 485                 loff_t pos = N_TXTOFF(ex);
 486
 487 #ifdef WARN_OLD
 488                 static unsigned long error_time;
 489                 if (time_after(jiffies, error_time + 5*HZ)) {
 490                         printk(KERN_WARNING
 491                                "N_TXTOFF is not page aligned. Please convert "
 492                                "library: %s\n",
 493                                file->f_path.dentry->d_name.name);
 494                         error_time = jiffies;
 495                 }
 496 #endif
 497                 down_write(&current->mm->mmap_sem);
 498                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 499                 up_write(&current->mm->mmap_sem);
 500
 501                 file->f_op->read(file, (char __user *)start_addr,
 502                         ex.a_text + ex.a_data, &pos);
 503                 flush_icache_range((unsigned long) start_addr,
 504                                    (unsigned long) start_addr + ex.a_text +
 505                                    ex.a_data);
 506
 507                 retval = 0;
 508                 goto out;
 509         }
 510         /* Now use mmap to map the library into memory. */
 511         down_write(&current->mm->mmap_sem);
 512         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 513                         PROT_READ | PROT_WRITE | PROT_EXEC,
 514                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 515                         N_TXTOFF(ex));
 516         up_write(&current->mm->mmap_sem);
 517         retval = error;
 518         if (error != start_addr)
 519                 goto out;
 520
 521         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 522         bss = ex.a_text + ex.a_data + ex.a_bss;
 523         if (bss > len) {
 524                 down_write(&current->mm->mmap_sem);
 525                 error = do_brk(start_addr + len, bss - len);
 526                 up_write(&current->mm->mmap_sem);
 527                 retval = error;
 528                 if (error != start_addr + len)
 529                         goto out;
 530         }
 531         retval = 0;
 532 out:
 533         return retval;
 534 }
 535
 536 static int __init init_aout_binfmt(void)
 537 {
 538         return register_binfmt(&aout_format);
 539 }
 540
 541 static void __exit exit_aout_binfmt(void)
 542 {
 543         unregister_binfmt(&aout_format);
 544 }
 545
 546 module_init(init_aout_binfmt);
 547 module_exit(exit_aout_binfmt);
 548 MODULE_LICENSE("GPL");