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/binfmts.h>
  25 #include <linux/personality.h>
  26 #include <linux/init.h>
  27 #include <linux/jiffies.h>
  28
  29 #include <asm/uaccess.h>
  30 #include <asm/pgalloc.h>
  31 #include <asm/cacheflush.h>
  32 #include <asm/user32.h>
  33 #include <asm/ia32.h>
  34
  35 #undef WARN_OLD
  36 #undef CORE_DUMP /* definitely broken */
  37
  38 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
  39 static int load_aout_library(struct file *);
  40
  41 #ifdef CORE_DUMP
  42 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
  43                           unsigned long limit);
  44
  45 /*
  46  * fill in the user structure for a core dump..
  47  */
  48 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  49 {
  50         u32 fs, gs;
  51
  52 /* changed the size calculations - should hopefully work better. lbt */
  53         dump->magic = CMAGIC;
  54         dump->start_code = 0;
  55         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  56         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  57         dump->u_dsize = ((unsigned long)
  58                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  59         dump->u_dsize -= dump->u_tsize;
  60         dump->u_ssize = 0;
  61         dump->u_debugreg[0] = current->thread.debugreg0;
  62         dump->u_debugreg[1] = current->thread.debugreg1;
  63         dump->u_debugreg[2] = current->thread.debugreg2;
  64         dump->u_debugreg[3] = current->thread.debugreg3;
  65         dump->u_debugreg[4] = 0;
  66         dump->u_debugreg[5] = 0;
  67         dump->u_debugreg[6] = current->thread.debugreg6;
  68         dump->u_debugreg[7] = current->thread.debugreg7;
  69
  70         if (dump->start_stack < 0xc0000000) {
  71                 unsigned long tmp;
  72
  73                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  74                 dump->u_ssize = tmp >> PAGE_SHIFT;
  75         }
  76
  77         dump->regs.bx = regs->bx;
  78         dump->regs.cx = regs->cx;
  79         dump->regs.dx = regs->dx;
  80         dump->regs.si = regs->si;
  81         dump->regs.di = regs->di;
  82         dump->regs.bp = regs->bp;
  83         dump->regs.ax = regs->ax;
  84         dump->regs.ds = current->thread.ds;
  85         dump->regs.es = current->thread.es;
  86         savesegment(fs, fs);
  87         dump->regs.fs = fs;
  88         savesegment(gs, gs);
  89         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 #include <linux/coredump.h>
 134
 135 #define DUMP_WRITE(addr, nr)                         \
 136         if (!dump_write(file, (void *)(addr), (nr))) \
 137                 goto end_coredump;
 138
 139 #define DUMP_SEEK(offset)               \
 140         if (!dump_seek(file, offset))   \
 141                 goto end_coredump;
 142
 143 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 144 #define START_STACK(u)  (u.start_stack)
 145
 146 /*
 147  * Routine writes a core dump image in the current directory.
 148  * Currently only a stub-function.
 149  *
 150  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 151  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 152  * field, which also makes sure the core-dumps won't be recursive if the
 153  * dumping of the process results in another error..
 154  */
 155
 156 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 157                           unsigned long limit)
 158 {
 159         mm_segment_t fs;
 160         int has_dumped = 0;
 161         unsigned long dump_start, dump_size;
 162         struct user32 dump;
 163
 164         fs = get_fs();
 165         set_fs(KERNEL_DS);
 166         has_dumped = 1;
 167         current->flags |= PF_DUMPCORE;
 168         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 169         dump.u_ar0 = offsetof(struct user32, regs);
 170         dump.signal = signr;
 171         dump_thread32(regs, &dump);
 172
 173         /*
 174          * If the size of the dump file exceeds the rlimit, then see
 175          * what would happen if we wrote the stack, but not the data
 176          * area.
 177          */
 178         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 179                 dump.u_dsize = 0;
 180
 181         /* Make sure we have enough room to write the stack and data areas. */
 182         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 183                 dump.u_ssize = 0;
 184
 185         /* make sure we actually have a data and stack area to dump */
 186         set_fs(USER_DS);
 187         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 188                        dump.u_dsize << PAGE_SHIFT))
 189                 dump.u_dsize = 0;
 190         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 191                        dump.u_ssize << PAGE_SHIFT))
 192                 dump.u_ssize = 0;
 193
 194         set_fs(KERNEL_DS);
 195         /* struct user */
 196         DUMP_WRITE(&dump, sizeof(dump));
 197         /* Now dump all of the user data.  Include malloced stuff as well */
 198         DUMP_SEEK(PAGE_SIZE);
 199         /* now we start writing out the user space info */
 200         set_fs(USER_DS);
 201         /* Dump the data area */
 202         if (dump.u_dsize != 0) {
 203                 dump_start = START_DATA(dump);
 204                 dump_size = dump.u_dsize << PAGE_SHIFT;
 205                 DUMP_WRITE(dump_start, dump_size);
 206         }
 207         /* Now prepare to dump the stack area */
 208         if (dump.u_ssize != 0) {
 209                 dump_start = START_STACK(dump);
 210                 dump_size = dump.u_ssize << PAGE_SHIFT;
 211                 DUMP_WRITE(dump_start, dump_size);
 212         }
 213 end_coredump:
 214         set_fs(fs);
 215         return has_dumped;
 216 }
 217 #endif
 218
 219 /*
 220  * create_aout_tables() parses the env- and arg-strings in new user
 221  * memory and creates the pointer tables from them, and puts their
 222  * addresses on the "stack", returning the new stack pointer value.
 223  */
 224 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 225 {
 226         u32 __user *argv, *envp, *sp;
 227         int argc = bprm->argc, envc = bprm->envc;
 228
 229         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 230         sp -= envc+1;
 231         envp = sp;
 232         sp -= argc+1;
 233         argv = sp;
 234         put_user((unsigned long) envp, --sp);
 235         put_user((unsigned long) argv, --sp);
 236         put_user(argc, --sp);
 237         current->mm->arg_start = (unsigned long) p;
 238         while (argc-- > 0) {
 239                 char c;
 240
 241                 put_user((u32)(unsigned long)p, argv++);
 242                 do {
 243                         get_user(c, p++);
 244                 } while (c);
 245         }
 246         put_user(0, argv);
 247         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 248         while (envc-- > 0) {
 249                 char c;
 250
 251                 put_user((u32)(unsigned long)p, envp++);
 252                 do {
 253                         get_user(c, p++);
 254                 } while (c);
 255         }
 256         put_user(0, envp);
 257         current->mm->env_end = (unsigned long) p;
 258         return sp;
 259 }
 260
 261 /*
 262  * These are the functions used to load a.out style executables and shared
 263  * libraries.  There is no binary dependent code anywhere else.
 264  */
 265 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 266 {
 267         unsigned long error, fd_offset, rlim;
 268         struct exec ex;
 269         int retval;
 270
 271         ex = *((struct exec *) bprm->buf);              /* exec-header */
 272         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 273              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 274             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 275             i_size_read(bprm->file->f_path.dentry->d_inode) <
 276             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 277                 return -ENOEXEC;
 278         }
 279
 280         fd_offset = N_TXTOFF(ex);
 281
 282         /* Check initial limits. This avoids letting people circumvent
 283          * size limits imposed on them by creating programs with large
 284          * arrays in the data or bss.
 285          */
 286         rlim = rlimit(RLIMIT_DATA);
 287         if (rlim >= RLIM_INFINITY)
 288                 rlim = ~0;
 289         if (ex.a_data + ex.a_bss > rlim)
 290                 return -ENOMEM;
 291
 292         /* Flush all traces of the currently running executable */
 293         retval = flush_old_exec(bprm);
 294         if (retval)
 295                 return retval;
 296
 297         /* OK, This is the point of no return */
 298         set_personality(PER_LINUX);
 299         set_thread_flag(TIF_IA32);
 300         current->mm->context.ia32_compat = 1;
 301
 302         setup_new_exec(bprm);
 303
 304         regs->cs = __USER32_CS;
 305         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 306                 regs->r13 = regs->r14 = regs->r15 = 0;
 307
 308         current->mm->end_code = ex.a_text +
 309                 (current->mm->start_code = N_TXTADDR(ex));
 310         current->mm->end_data = ex.a_data +
 311                 (current->mm->start_data = N_DATADDR(ex));
 312         current->mm->brk = ex.a_bss +
 313                 (current->mm->start_brk = N_BSSADDR(ex));
 314         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 315         current->mm->cached_hole_size = 0;
 316
 317         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 318         if (retval < 0) {
 319                 /* Someone check-me: is this error path enough? */
 320                 send_sig(SIGKILL, current, 0);
 321                 return retval;
 322         }
 323
 324         install_exec_creds(bprm);
 325
 326         if (N_MAGIC(ex) == OMAGIC) {
 327                 unsigned long text_addr, map_size;
 328                 loff_t pos;
 329
 330                 text_addr = N_TXTADDR(ex);
 331
 332                 pos = 32;
 333                 map_size = ex.a_text+ex.a_data;
 334
 335                 down_write(&current->mm->mmap_sem);
 336                 error = do_brk(text_addr & PAGE_MASK, map_size);
 337                 up_write(&current->mm->mmap_sem);
 338
 339                 if (error != (text_addr & PAGE_MASK)) {
 340                         send_sig(SIGKILL, current, 0);
 341                         return error;
 342                 }
 343
 344                 error = bprm->file->f_op->read(bprm->file,
 345                          (char __user *)text_addr,
 346                           ex.a_text+ex.a_data, &pos);
 347                 if ((signed long)error < 0) {
 348                         send_sig(SIGKILL, current, 0);
 349                         return error;
 350                 }
 351
 352                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 353         } else {
 354 #ifdef WARN_OLD
 355                 static unsigned long error_time, error_time2;
 356                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 357                     (N_MAGIC(ex) != NMAGIC) &&
 358                                 time_after(jiffies, error_time2 + 5*HZ)) {
 359                         printk(KERN_NOTICE "executable not page aligned\n");
 360                         error_time2 = jiffies;
 361                 }
 362
 363                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 364                             time_after(jiffies, error_time + 5*HZ)) {
 365                         printk(KERN_WARNING
 366                                "fd_offset is not page aligned. Please convert "
 367                                "program: %s\n",
 368                                bprm->file->f_path.dentry->d_name.name);
 369                         error_time = jiffies;
 370                 }
 371 #endif
 372
 373                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 374                         loff_t pos = fd_offset;
 375
 376                         down_write(&current->mm->mmap_sem);
 377                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 378                         up_write(&current->mm->mmap_sem);
 379                         bprm->file->f_op->read(bprm->file,
 380                                         (char __user *)N_TXTADDR(ex),
 381                                         ex.a_text+ex.a_data, &pos);
 382                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 383                                            (unsigned long) N_TXTADDR(ex) +
 384                                            ex.a_text+ex.a_data);
 385                         goto beyond_if;
 386                 }
 387
 388                 down_write(&current->mm->mmap_sem);
 389                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 390                                 PROT_READ | PROT_EXEC,
 391                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 392                                 MAP_EXECUTABLE | MAP_32BIT,
 393                                 fd_offset);
 394                 up_write(&current->mm->mmap_sem);
 395
 396                 if (error != N_TXTADDR(ex)) {
 397                         send_sig(SIGKILL, current, 0);
 398                         return error;
 399                 }
 400
 401                 down_write(&current->mm->mmap_sem);
 402                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 403                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 404                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 405                                 MAP_EXECUTABLE | MAP_32BIT,
 406                                 fd_offset + ex.a_text);
 407                 up_write(&current->mm->mmap_sem);
 408                 if (error != N_DATADDR(ex)) {
 409                         send_sig(SIGKILL, current, 0);
 410                         return error;
 411                 }
 412         }
 413 beyond_if:
 414         set_binfmt(&aout_format);
 415
 416         set_brk(current->mm->start_brk, current->mm->brk);
 417
 418         current->mm->start_stack =
 419                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 420         /* start thread */
 421         loadsegment(fs, 0);
 422         loadsegment(ds, __USER32_DS);
 423         loadsegment(es, __USER32_DS);
 424         load_gs_index(0);
 425         (regs)->ip = ex.a_entry;
 426         (regs)->sp = current->mm->start_stack;
 427         (regs)->flags = 0x200;
 428         (regs)->cs = __USER32_CS;
 429         (regs)->ss = __USER32_DS;
 430         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 431         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 432         set_fs(USER_DS);
 433         return 0;
 434 }
 435
 436 static int load_aout_library(struct file *file)
 437 {
 438         struct inode *inode;
 439         unsigned long bss, start_addr, len, error;
 440         int retval;
 441         struct exec ex;
 442
 443         inode = file->f_path.dentry->d_inode;
 444
 445         retval = -ENOEXEC;
 446         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 447         if (error != sizeof(ex))
 448                 goto out;
 449
 450         /* We come in here for the regular a.out style of shared libraries */
 451         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 452             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 453             i_size_read(inode) <
 454             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 455                 goto out;
 456         }
 457
 458         if (N_FLAGS(ex))
 459                 goto out;
 460
 461         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 462            this off to get the starting address for the page */
 463
 464         start_addr =  ex.a_entry & 0xfffff000;
 465
 466         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 467                 loff_t pos = N_TXTOFF(ex);
 468
 469 #ifdef WARN_OLD
 470                 static unsigned long error_time;
 471                 if (time_after(jiffies, error_time + 5*HZ)) {
 472                         printk(KERN_WARNING
 473                                "N_TXTOFF is not page aligned. Please convert "
 474                                "library: %s\n",
 475                                file->f_path.dentry->d_name.name);
 476                         error_time = jiffies;
 477                 }
 478 #endif
 479                 down_write(&current->mm->mmap_sem);
 480                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 481                 up_write(&current->mm->mmap_sem);
 482
 483                 file->f_op->read(file, (char __user *)start_addr,
 484                         ex.a_text + ex.a_data, &pos);
 485                 flush_icache_range((unsigned long) start_addr,
 486                                    (unsigned long) start_addr + ex.a_text +
 487                                    ex.a_data);
 488
 489                 retval = 0;
 490                 goto out;
 491         }
 492         /* Now use mmap to map the library into memory. */
 493         down_write(&current->mm->mmap_sem);
 494         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 495                         PROT_READ | PROT_WRITE | PROT_EXEC,
 496                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 497                         N_TXTOFF(ex));
 498         up_write(&current->mm->mmap_sem);
 499         retval = error;
 500         if (error != start_addr)
 501                 goto out;
 502
 503         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 504         bss = ex.a_text + ex.a_data + ex.a_bss;
 505         if (bss > len) {
 506                 down_write(&current->mm->mmap_sem);
 507                 error = do_brk(start_addr + len, bss - len);
 508                 up_write(&current->mm->mmap_sem);
 509                 retval = error;
 510                 if (error != start_addr + len)
 511                         goto out;
 512         }
 513         retval = 0;
 514 out:
 515         return retval;
 516 }
 517
 518 static int __init init_aout_binfmt(void)
 519 {
 520         register_binfmt(&aout_format);
 521         return 0;
 522 }
 523
 524 static void __exit exit_aout_binfmt(void)
 525 {
 526         unregister_binfmt(&aout_format);
 527 }
 528
 529 module_init(init_aout_binfmt);
 530 module_exit(exit_aout_binfmt);
 531 MODULE_LICENSE("GPL");