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 *);
  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         vm_brk(start, end - start);
 123 }
 124
 125 #ifdef CORE_DUMP
 126 /*
 127  * These are the only things you should do on a core-file: use only these
 128  * macros to write out all the necessary info.
 129  */
 130
 131 #include <linux/coredump.h>
 132
 133 #define DUMP_WRITE(addr, nr)                         \
 134         if (!dump_write(file, (void *)(addr), (nr))) \
 135                 goto end_coredump;
 136
 137 #define DUMP_SEEK(offset)               \
 138         if (!dump_seek(file, offset))   \
 139                 goto end_coredump;
 140
 141 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 142 #define START_STACK(u)  (u.start_stack)
 143
 144 /*
 145  * Routine writes a core dump image in the current directory.
 146  * Currently only a stub-function.
 147  *
 148  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 149  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 150  * field, which also makes sure the core-dumps won't be recursive if the
 151  * dumping of the process results in another error..
 152  */
 153
 154 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 155                           unsigned long limit)
 156 {
 157         mm_segment_t fs;
 158         int has_dumped = 0;
 159         unsigned long dump_start, dump_size;
 160         struct user32 dump;
 161
 162         fs = get_fs();
 163         set_fs(KERNEL_DS);
 164         has_dumped = 1;
 165         current->flags |= PF_DUMPCORE;
 166         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 167         dump.u_ar0 = offsetof(struct user32, regs);
 168         dump.signal = signr;
 169         dump_thread32(regs, &dump);
 170
 171         /*
 172          * If the size of the dump file exceeds the rlimit, then see
 173          * what would happen if we wrote the stack, but not the data
 174          * area.
 175          */
 176         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 177                 dump.u_dsize = 0;
 178
 179         /* Make sure we have enough room to write the stack and data areas. */
 180         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 181                 dump.u_ssize = 0;
 182
 183         /* make sure we actually have a data and stack area to dump */
 184         set_fs(USER_DS);
 185         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 186                        dump.u_dsize << PAGE_SHIFT))
 187                 dump.u_dsize = 0;
 188         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 189                        dump.u_ssize << PAGE_SHIFT))
 190                 dump.u_ssize = 0;
 191
 192         set_fs(KERNEL_DS);
 193         /* struct user */
 194         DUMP_WRITE(&dump, sizeof(dump));
 195         /* Now dump all of the user data.  Include malloced stuff as well */
 196         DUMP_SEEK(PAGE_SIZE);
 197         /* now we start writing out the user space info */
 198         set_fs(USER_DS);
 199         /* Dump the data area */
 200         if (dump.u_dsize != 0) {
 201                 dump_start = START_DATA(dump);
 202                 dump_size = dump.u_dsize << PAGE_SHIFT;
 203                 DUMP_WRITE(dump_start, dump_size);
 204         }
 205         /* Now prepare to dump the stack area */
 206         if (dump.u_ssize != 0) {
 207                 dump_start = START_STACK(dump);
 208                 dump_size = dump.u_ssize << PAGE_SHIFT;
 209                 DUMP_WRITE(dump_start, dump_size);
 210         }
 211 end_coredump:
 212         set_fs(fs);
 213         return has_dumped;
 214 }
 215 #endif
 216
 217 /*
 218  * create_aout_tables() parses the env- and arg-strings in new user
 219  * memory and creates the pointer tables from them, and puts their
 220  * addresses on the "stack", returning the new stack pointer value.
 221  */
 222 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 223 {
 224         u32 __user *argv, *envp, *sp;
 225         int argc = bprm->argc, envc = bprm->envc;
 226
 227         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 228         sp -= envc+1;
 229         envp = sp;
 230         sp -= argc+1;
 231         argv = sp;
 232         put_user((unsigned long) envp, --sp);
 233         put_user((unsigned long) argv, --sp);
 234         put_user(argc, --sp);
 235         current->mm->arg_start = (unsigned long) p;
 236         while (argc-- > 0) {
 237                 char c;
 238
 239                 put_user((u32)(unsigned long)p, argv++);
 240                 do {
 241                         get_user(c, p++);
 242                 } while (c);
 243         }
 244         put_user(0, argv);
 245         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 246         while (envc-- > 0) {
 247                 char c;
 248
 249                 put_user((u32)(unsigned long)p, envp++);
 250                 do {
 251                         get_user(c, p++);
 252                 } while (c);
 253         }
 254         put_user(0, envp);
 255         current->mm->env_end = (unsigned long) p;
 256         return sp;
 257 }
 258
 259 /*
 260  * These are the functions used to load a.out style executables and shared
 261  * libraries.  There is no binary dependent code anywhere else.
 262  */
 263 static int load_aout_binary(struct linux_binprm *bprm)
 264 {
 265         unsigned long error, fd_offset, rlim;
 266         struct pt_regs *regs = current_pt_regs();
 267         struct exec ex;
 268         int retval;
 269
 270         ex = *((struct exec *) bprm->buf);              /* exec-header */
 271         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 272              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 273             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 274             i_size_read(bprm->file->f_path.dentry->d_inode) <
 275             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 276                 return -ENOEXEC;
 277         }
 278
 279         fd_offset = N_TXTOFF(ex);
 280
 281         /* Check initial limits. This avoids letting people circumvent
 282          * size limits imposed on them by creating programs with large
 283          * arrays in the data or bss.
 284          */
 285         rlim = rlimit(RLIMIT_DATA);
 286         if (rlim >= RLIM_INFINITY)
 287                 rlim = ~0;
 288         if (ex.a_data + ex.a_bss > rlim)
 289                 return -ENOMEM;
 290
 291         /* Flush all traces of the currently running executable */
 292         retval = flush_old_exec(bprm);
 293         if (retval)
 294                 return retval;
 295
 296         /* OK, This is the point of no return */
 297         set_personality(PER_LINUX);
 298         set_personality_ia32(false);
 299
 300         setup_new_exec(bprm);
 301
 302         regs->cs = __USER32_CS;
 303         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 304                 regs->r13 = regs->r14 = regs->r15 = 0;
 305
 306         current->mm->end_code = ex.a_text +
 307                 (current->mm->start_code = N_TXTADDR(ex));
 308         current->mm->end_data = ex.a_data +
 309                 (current->mm->start_data = N_DATADDR(ex));
 310         current->mm->brk = ex.a_bss +
 311                 (current->mm->start_brk = N_BSSADDR(ex));
 312         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 313         current->mm->cached_hole_size = 0;
 314
 315         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 316         if (retval < 0) {
 317                 /* Someone check-me: is this error path enough? */
 318                 send_sig(SIGKILL, current, 0);
 319                 return retval;
 320         }
 321
 322         install_exec_creds(bprm);
 323
 324         if (N_MAGIC(ex) == OMAGIC) {
 325                 unsigned long text_addr, map_size;
 326                 loff_t pos;
 327
 328                 text_addr = N_TXTADDR(ex);
 329
 330                 pos = 32;
 331                 map_size = ex.a_text+ex.a_data;
 332
 333                 error = vm_brk(text_addr & PAGE_MASK, map_size);
 334
 335                 if (error != (text_addr & PAGE_MASK)) {
 336                         send_sig(SIGKILL, current, 0);
 337                         return error;
 338                 }
 339
 340                 error = bprm->file->f_op->read(bprm->file,
 341                          (char __user *)text_addr,
 342                           ex.a_text+ex.a_data, &pos);
 343                 if ((signed long)error < 0) {
 344                         send_sig(SIGKILL, current, 0);
 345                         return error;
 346                 }
 347
 348                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 349         } else {
 350 #ifdef WARN_OLD
 351                 static unsigned long error_time, error_time2;
 352                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 353                     (N_MAGIC(ex) != NMAGIC) &&
 354                                 time_after(jiffies, error_time2 + 5*HZ)) {
 355                         printk(KERN_NOTICE "executable not page aligned\n");
 356                         error_time2 = jiffies;
 357                 }
 358
 359                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 360                             time_after(jiffies, error_time + 5*HZ)) {
 361                         printk(KERN_WARNING
 362                                "fd_offset is not page aligned. Please convert "
 363                                "program: %s\n",
 364                                bprm->file->f_path.dentry->d_name.name);
 365                         error_time = jiffies;
 366                 }
 367 #endif
 368
 369                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 370                         loff_t pos = fd_offset;
 371
 372                         vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 373                         bprm->file->f_op->read(bprm->file,
 374                                         (char __user *)N_TXTADDR(ex),
 375                                         ex.a_text+ex.a_data, &pos);
 376                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 377                                            (unsigned long) N_TXTADDR(ex) +
 378                                            ex.a_text+ex.a_data);
 379                         goto beyond_if;
 380                 }
 381
 382                 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 383                                 PROT_READ | PROT_EXEC,
 384                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 385                                 MAP_EXECUTABLE | MAP_32BIT,
 386                                 fd_offset);
 387
 388                 if (error != N_TXTADDR(ex)) {
 389                         send_sig(SIGKILL, current, 0);
 390                         return error;
 391                 }
 392
 393                 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 394                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 395                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 396                                 MAP_EXECUTABLE | MAP_32BIT,
 397                                 fd_offset + ex.a_text);
 398                 if (error != N_DATADDR(ex)) {
 399                         send_sig(SIGKILL, current, 0);
 400                         return error;
 401                 }
 402         }
 403 beyond_if:
 404         set_binfmt(&aout_format);
 405
 406         set_brk(current->mm->start_brk, current->mm->brk);
 407
 408         current->mm->start_stack =
 409                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 410         /* start thread */
 411         loadsegment(fs, 0);
 412         loadsegment(ds, __USER32_DS);
 413         loadsegment(es, __USER32_DS);
 414         load_gs_index(0);
 415         (regs)->ip = ex.a_entry;
 416         (regs)->sp = current->mm->start_stack;
 417         (regs)->flags = 0x200;
 418         (regs)->cs = __USER32_CS;
 419         (regs)->ss = __USER32_DS;
 420         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 421         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 422         set_fs(USER_DS);
 423         return 0;
 424 }
 425
 426 static int load_aout_library(struct file *file)
 427 {
 428         struct inode *inode;
 429         unsigned long bss, start_addr, len, error;
 430         int retval;
 431         struct exec ex;
 432
 433         inode = file->f_path.dentry->d_inode;
 434
 435         retval = -ENOEXEC;
 436         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 437         if (error != sizeof(ex))
 438                 goto out;
 439
 440         /* We come in here for the regular a.out style of shared libraries */
 441         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 442             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 443             i_size_read(inode) <
 444             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 445                 goto out;
 446         }
 447
 448         if (N_FLAGS(ex))
 449                 goto out;
 450
 451         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 452            this off to get the starting address for the page */
 453
 454         start_addr =  ex.a_entry & 0xfffff000;
 455
 456         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 457                 loff_t pos = N_TXTOFF(ex);
 458
 459 #ifdef WARN_OLD
 460                 static unsigned long error_time;
 461                 if (time_after(jiffies, error_time + 5*HZ)) {
 462                         printk(KERN_WARNING
 463                                "N_TXTOFF is not page aligned. Please convert "
 464                                "library: %s\n",
 465                                file->f_path.dentry->d_name.name);
 466                         error_time = jiffies;
 467                 }
 468 #endif
 469                 vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 470
 471                 file->f_op->read(file, (char __user *)start_addr,
 472                         ex.a_text + ex.a_data, &pos);
 473                 flush_icache_range((unsigned long) start_addr,
 474                                    (unsigned long) start_addr + ex.a_text +
 475                                    ex.a_data);
 476
 477                 retval = 0;
 478                 goto out;
 479         }
 480         /* Now use mmap to map the library into memory. */
 481         error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
 482                         PROT_READ | PROT_WRITE | PROT_EXEC,
 483                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 484                         N_TXTOFF(ex));
 485         retval = error;
 486         if (error != start_addr)
 487                 goto out;
 488
 489         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 490         bss = ex.a_text + ex.a_data + ex.a_bss;
 491         if (bss > len) {
 492                 error = vm_brk(start_addr + len, bss - len);
 493                 retval = error;
 494                 if (error != start_addr + len)
 495                         goto out;
 496         }
 497         retval = 0;
 498 out:
 499         return retval;
 500 }
 501
 502 static int __init init_aout_binfmt(void)
 503 {
 504         register_binfmt(&aout_format);
 505         return 0;
 506 }
 507
 508 static void __exit exit_aout_binfmt(void)
 509 {
 510         unregister_binfmt(&aout_format);
 511 }
 512
 513 module_init(init_aout_binfmt);
 514 module_exit(exit_aout_binfmt);
 515 MODULE_LICENSE("GPL");