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/system.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgalloc.h>
  32 #include <asm/cacheflush.h>
  33 #include <asm/user32.h>
  34 #include <asm/ia32.h>
  35
  36 #undef WARN_OLD
  37 #undef CORE_DUMP /* definitely broken */
  38
  39 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
  40 static int load_aout_library(struct file *);
  41
  42 #ifdef CORE_DUMP
  43 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
  44                           unsigned long limit);
  45
  46 /*
  47  * fill in the user structure for a core dump..
  48  */
  49 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  50 {
  51         u32 fs, gs;
  52
  53 /* changed the size calculations - should hopefully work better. lbt */
  54         dump->magic = CMAGIC;
  55         dump->start_code = 0;
  56         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  57         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  58         dump->u_dsize = ((unsigned long)
  59                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  60         dump->u_dsize -= dump->u_tsize;
  61         dump->u_ssize = 0;
  62         dump->u_debugreg[0] = current->thread.debugreg0;
  63         dump->u_debugreg[1] = current->thread.debugreg1;
  64         dump->u_debugreg[2] = current->thread.debugreg2;
  65         dump->u_debugreg[3] = current->thread.debugreg3;
  66         dump->u_debugreg[4] = 0;
  67         dump->u_debugreg[5] = 0;
  68         dump->u_debugreg[6] = current->thread.debugreg6;
  69         dump->u_debugreg[7] = current->thread.debugreg7;
  70
  71         if (dump->start_stack < 0xc0000000) {
  72                 unsigned long tmp;
  73
  74                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  75                 dump->u_ssize = tmp >> PAGE_SHIFT;
  76         }
  77
  78         dump->regs.bx = regs->bx;
  79         dump->regs.cx = regs->cx;
  80         dump->regs.dx = regs->dx;
  81         dump->regs.si = regs->si;
  82         dump->regs.di = regs->di;
  83         dump->regs.bp = regs->bp;
  84         dump->regs.ax = regs->ax;
  85         dump->regs.ds = current->thread.ds;
  86         dump->regs.es = current->thread.es;
  87         savesegment(fs, fs);
  88         dump->regs.fs = fs;
  89         savesegment(gs, gs);
  90         dump->regs.gs = gs;
  91         dump->regs.orig_ax = regs->orig_ax;
  92         dump->regs.ip = regs->ip;
  93         dump->regs.cs = regs->cs;
  94         dump->regs.flags = regs->flags;
  95         dump->regs.sp = regs->sp;
  96         dump->regs.ss = regs->ss;
  97
  98 #if 1 /* FIXME */
  99         dump->u_fpvalid = 0;
 100 #else
 101         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 102 #endif
 103 }
 104
 105 #endif
 106
 107 static struct linux_binfmt aout_format = {
 108         .module         = THIS_MODULE,
 109         .load_binary    = load_aout_binary,
 110         .load_shlib     = load_aout_library,
 111 #ifdef CORE_DUMP
 112         .core_dump      = aout_core_dump,
 113 #endif
 114         .min_coredump   = PAGE_SIZE
 115 };
 116
 117 static void set_brk(unsigned long start, unsigned long end)
 118 {
 119         start = PAGE_ALIGN(start);
 120         end = PAGE_ALIGN(end);
 121         if (end <= start)
 122                 return;
 123         down_write(&current->mm->mmap_sem);
 124         do_brk(start, end - start);
 125         up_write(&current->mm->mmap_sem);
 126 }
 127
 128 #ifdef CORE_DUMP
 129 /*
 130  * These are the only things you should do on a core-file: use only these
 131  * macros to write out all the necessary info.
 132  */
 133
 134 #include <linux/coredump.h>
 135
 136 #define DUMP_WRITE(addr, nr)                         \
 137         if (!dump_write(file, (void *)(addr), (nr))) \
 138                 goto end_coredump;
 139
 140 #define DUMP_SEEK(offset)               \
 141         if (!dump_seek(file, offset))   \
 142                 goto end_coredump;
 143
 144 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 145 #define START_STACK(u)  (u.start_stack)
 146
 147 /*
 148  * Routine writes a core dump image in the current directory.
 149  * Currently only a stub-function.
 150  *
 151  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 152  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 153  * field, which also makes sure the core-dumps won't be recursive if the
 154  * dumping of the process results in another error..
 155  */
 156
 157 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 158                           unsigned long limit)
 159 {
 160         mm_segment_t fs;
 161         int has_dumped = 0;
 162         unsigned long dump_start, dump_size;
 163         struct user32 dump;
 164
 165         fs = get_fs();
 166         set_fs(KERNEL_DS);
 167         has_dumped = 1;
 168         current->flags |= PF_DUMPCORE;
 169         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 170         dump.u_ar0 = offsetof(struct user32, regs);
 171         dump.signal = signr;
 172         dump_thread32(regs, &dump);
 173
 174         /*
 175          * If the size of the dump file exceeds the rlimit, then see
 176          * what would happen if we wrote the stack, but not the data
 177          * area.
 178          */
 179         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 180                 dump.u_dsize = 0;
 181
 182         /* Make sure we have enough room to write the stack and data areas. */
 183         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 184                 dump.u_ssize = 0;
 185
 186         /* make sure we actually have a data and stack area to dump */
 187         set_fs(USER_DS);
 188         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 189                        dump.u_dsize << PAGE_SHIFT))
 190                 dump.u_dsize = 0;
 191         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 192                        dump.u_ssize << PAGE_SHIFT))
 193                 dump.u_ssize = 0;
 194
 195         set_fs(KERNEL_DS);
 196         /* struct user */
 197         DUMP_WRITE(&dump, sizeof(dump));
 198         /* Now dump all of the user data.  Include malloced stuff as well */
 199         DUMP_SEEK(PAGE_SIZE);
 200         /* now we start writing out the user space info */
 201         set_fs(USER_DS);
 202         /* Dump the data area */
 203         if (dump.u_dsize != 0) {
 204                 dump_start = START_DATA(dump);
 205                 dump_size = dump.u_dsize << PAGE_SHIFT;
 206                 DUMP_WRITE(dump_start, dump_size);
 207         }
 208         /* Now prepare to dump the stack area */
 209         if (dump.u_ssize != 0) {
 210                 dump_start = START_STACK(dump);
 211                 dump_size = dump.u_ssize << PAGE_SHIFT;
 212                 DUMP_WRITE(dump_start, dump_size);
 213         }
 214 end_coredump:
 215         set_fs(fs);
 216         return has_dumped;
 217 }
 218 #endif
 219
 220 /*
 221  * create_aout_tables() parses the env- and arg-strings in new user
 222  * memory and creates the pointer tables from them, and puts their
 223  * addresses on the "stack", returning the new stack pointer value.
 224  */
 225 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 226 {
 227         u32 __user *argv, *envp, *sp;
 228         int argc = bprm->argc, envc = bprm->envc;
 229
 230         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 231         sp -= envc+1;
 232         envp = sp;
 233         sp -= argc+1;
 234         argv = sp;
 235         put_user((unsigned long) envp, --sp);
 236         put_user((unsigned long) argv, --sp);
 237         put_user(argc, --sp);
 238         current->mm->arg_start = (unsigned long) p;
 239         while (argc-- > 0) {
 240                 char c;
 241
 242                 put_user((u32)(unsigned long)p, argv++);
 243                 do {
 244                         get_user(c, p++);
 245                 } while (c);
 246         }
 247         put_user(0, argv);
 248         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 249         while (envc-- > 0) {
 250                 char c;
 251
 252                 put_user((u32)(unsigned long)p, envp++);
 253                 do {
 254                         get_user(c, p++);
 255                 } while (c);
 256         }
 257         put_user(0, envp);
 258         current->mm->env_end = (unsigned long) p;
 259         return sp;
 260 }
 261
 262 /*
 263  * These are the functions used to load a.out style executables and shared
 264  * libraries.  There is no binary dependent code anywhere else.
 265  */
 266 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 267 {
 268         unsigned long error, fd_offset, rlim;
 269         struct exec ex;
 270         int retval;
 271
 272         ex = *((struct exec *) bprm->buf);              /* exec-header */
 273         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 274              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 275             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 276             i_size_read(bprm->file->f_path.dentry->d_inode) <
 277             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 278                 return -ENOEXEC;
 279         }
 280
 281         fd_offset = N_TXTOFF(ex);
 282
 283         /* Check initial limits. This avoids letting people circumvent
 284          * size limits imposed on them by creating programs with large
 285          * arrays in the data or bss.
 286          */
 287         rlim = rlimit(RLIMIT_DATA);
 288         if (rlim >= RLIM_INFINITY)
 289                 rlim = ~0;
 290         if (ex.a_data + ex.a_bss > rlim)
 291                 return -ENOMEM;
 292
 293         /* Flush all traces of the currently running executable */
 294         retval = flush_old_exec(bprm);
 295         if (retval)
 296                 return retval;
 297
 298         /* OK, This is the point of no return */
 299         set_personality(PER_LINUX);
 300         set_thread_flag(TIF_IA32);
 301         current->mm->context.ia32_compat = 1;
 302
 303         setup_new_exec(bprm);
 304
 305         regs->cs = __USER32_CS;
 306         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 307                 regs->r13 = regs->r14 = regs->r15 = 0;
 308
 309         current->mm->end_code = ex.a_text +
 310                 (current->mm->start_code = N_TXTADDR(ex));
 311         current->mm->end_data = ex.a_data +
 312                 (current->mm->start_data = N_DATADDR(ex));
 313         current->mm->brk = ex.a_bss +
 314                 (current->mm->start_brk = N_BSSADDR(ex));
 315         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 316         current->mm->cached_hole_size = 0;
 317
 318         install_exec_creds(bprm);
 319         current->flags &= ~PF_FORKNOEXEC;
 320
 321         if (N_MAGIC(ex) == OMAGIC) {
 322                 unsigned long text_addr, map_size;
 323                 loff_t pos;
 324
 325                 text_addr = N_TXTADDR(ex);
 326
 327                 pos = 32;
 328                 map_size = ex.a_text+ex.a_data;
 329
 330                 down_write(&current->mm->mmap_sem);
 331                 error = do_brk(text_addr & PAGE_MASK, map_size);
 332                 up_write(&current->mm->mmap_sem);
 333
 334                 if (error != (text_addr & PAGE_MASK)) {
 335                         send_sig(SIGKILL, current, 0);
 336                         return error;
 337                 }
 338
 339                 error = bprm->file->f_op->read(bprm->file,
 340                          (char __user *)text_addr,
 341                           ex.a_text+ex.a_data, &pos);
 342                 if ((signed long)error < 0) {
 343                         send_sig(SIGKILL, current, 0);
 344                         return error;
 345                 }
 346
 347                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 348         } else {
 349 #ifdef WARN_OLD
 350                 static unsigned long error_time, error_time2;
 351                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 352                     (N_MAGIC(ex) != NMAGIC) &&
 353                                 time_after(jiffies, error_time2 + 5*HZ)) {
 354                         printk(KERN_NOTICE "executable not page aligned\n");
 355                         error_time2 = jiffies;
 356                 }
 357
 358                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 359                             time_after(jiffies, error_time + 5*HZ)) {
 360                         printk(KERN_WARNING
 361                                "fd_offset is not page aligned. Please convert "
 362                                "program: %s\n",
 363                                bprm->file->f_path.dentry->d_name.name);
 364                         error_time = jiffies;
 365                 }
 366 #endif
 367
 368                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 369                         loff_t pos = fd_offset;
 370
 371                         down_write(&current->mm->mmap_sem);
 372                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 373                         up_write(&current->mm->mmap_sem);
 374                         bprm->file->f_op->read(bprm->file,
 375                                         (char __user *)N_TXTADDR(ex),
 376                                         ex.a_text+ex.a_data, &pos);
 377                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 378                                            (unsigned long) N_TXTADDR(ex) +
 379                                            ex.a_text+ex.a_data);
 380                         goto beyond_if;
 381                 }
 382
 383                 down_write(&current->mm->mmap_sem);
 384                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 385                                 PROT_READ | PROT_EXEC,
 386                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 387                                 MAP_EXECUTABLE | MAP_32BIT,
 388                                 fd_offset);
 389                 up_write(&current->mm->mmap_sem);
 390
 391                 if (error != N_TXTADDR(ex)) {
 392                         send_sig(SIGKILL, current, 0);
 393                         return error;
 394                 }
 395
 396                 down_write(&current->mm->mmap_sem);
 397                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 398                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 399                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 400                                 MAP_EXECUTABLE | MAP_32BIT,
 401                                 fd_offset + ex.a_text);
 402                 up_write(&current->mm->mmap_sem);
 403                 if (error != N_DATADDR(ex)) {
 404                         send_sig(SIGKILL, current, 0);
 405                         return error;
 406                 }
 407         }
 408 beyond_if:
 409         set_binfmt(&aout_format);
 410
 411         set_brk(current->mm->start_brk, current->mm->brk);
 412
 413         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 414         if (retval < 0) {
 415                 /* Someone check-me: is this error path enough? */
 416                 send_sig(SIGKILL, current, 0);
 417                 return retval;
 418         }
 419
 420         current->mm->start_stack =
 421                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 422         /* start thread */
 423         loadsegment(fs, 0);
 424         loadsegment(ds, __USER32_DS);
 425         loadsegment(es, __USER32_DS);
 426         load_gs_index(0);
 427         (regs)->ip = ex.a_entry;
 428         (regs)->sp = current->mm->start_stack;
 429         (regs)->flags = 0x200;
 430         (regs)->cs = __USER32_CS;
 431         (regs)->ss = __USER32_DS;
 432         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 433         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 434         set_fs(USER_DS);
 435         return 0;
 436 }
 437
 438 static int load_aout_library(struct file *file)
 439 {
 440         struct inode *inode;
 441         unsigned long bss, start_addr, len, error;
 442         int retval;
 443         struct exec ex;
 444
 445         inode = file->f_path.dentry->d_inode;
 446
 447         retval = -ENOEXEC;
 448         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 449         if (error != sizeof(ex))
 450                 goto out;
 451
 452         /* We come in here for the regular a.out style of shared libraries */
 453         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 454             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 455             i_size_read(inode) <
 456             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 457                 goto out;
 458         }
 459
 460         if (N_FLAGS(ex))
 461                 goto out;
 462
 463         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 464            this off to get the starting address for the page */
 465
 466         start_addr =  ex.a_entry & 0xfffff000;
 467
 468         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 469                 loff_t pos = N_TXTOFF(ex);
 470
 471 #ifdef WARN_OLD
 472                 static unsigned long error_time;
 473                 if (time_after(jiffies, error_time + 5*HZ)) {
 474                         printk(KERN_WARNING
 475                                "N_TXTOFF is not page aligned. Please convert "
 476                                "library: %s\n",
 477                                file->f_path.dentry->d_name.name);
 478                         error_time = jiffies;
 479                 }
 480 #endif
 481                 down_write(&current->mm->mmap_sem);
 482                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 483                 up_write(&current->mm->mmap_sem);
 484
 485                 file->f_op->read(file, (char __user *)start_addr,
 486                         ex.a_text + ex.a_data, &pos);
 487                 flush_icache_range((unsigned long) start_addr,
 488                                    (unsigned long) start_addr + ex.a_text +
 489                                    ex.a_data);
 490
 491                 retval = 0;
 492                 goto out;
 493         }
 494         /* Now use mmap to map the library into memory. */
 495         down_write(&current->mm->mmap_sem);
 496         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 497                         PROT_READ | PROT_WRITE | PROT_EXEC,
 498                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 499                         N_TXTOFF(ex));
 500         up_write(&current->mm->mmap_sem);
 501         retval = error;
 502         if (error != start_addr)
 503                 goto out;
 504
 505         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 506         bss = ex.a_text + ex.a_data + ex.a_bss;
 507         if (bss > len) {
 508                 down_write(&current->mm->mmap_sem);
 509                 error = do_brk(start_addr + len, bss - len);
 510                 up_write(&current->mm->mmap_sem);
 511                 retval = error;
 512                 if (error != start_addr + len)
 513                         goto out;
 514         }
 515         retval = 0;
 516 out:
 517         return retval;
 518 }
 519
 520 static int __init init_aout_binfmt(void)
 521 {
 522         return register_binfmt(&aout_format);
 523 }
 524
 525 static void __exit exit_aout_binfmt(void)
 526 {
 527         unregister_binfmt(&aout_format);
 528 }
 529
 530 module_init(init_aout_binfmt);
 531 module_exit(exit_aout_binfmt);
 532 MODULE_LICENSE("GPL");