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