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
  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 /* probably 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, 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->rsp & ~(PAGE_SIZE - 1);
  56         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  57         dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  58         dump->u_dsize -= dump->u_tsize;
  59         dump->u_ssize = 0;
  60         dump->u_debugreg[0] = current->thread.debugreg0;
  61         dump->u_debugreg[1] = current->thread.debugreg1;
  62         dump->u_debugreg[2] = current->thread.debugreg2;
  63         dump->u_debugreg[3] = current->thread.debugreg3;
  64         dump->u_debugreg[4] = 0;
  65         dump->u_debugreg[5] = 0;
  66         dump->u_debugreg[6] = current->thread.debugreg6;
  67         dump->u_debugreg[7] = current->thread.debugreg7;
  68
  69         if (dump->start_stack < 0xc0000000)
  70                 dump->u_ssize = ((unsigned long) (0xc0000000 - dump->start_stack)) >> PAGE_SHIFT;
  71
  72         dump->regs.ebx = regs->rbx;
  73         dump->regs.ecx = regs->rcx;
  74         dump->regs.edx = regs->rdx;
  75         dump->regs.esi = regs->rsi;
  76         dump->regs.edi = regs->rdi;
  77         dump->regs.ebp = regs->rbp;
  78         dump->regs.eax = regs->rax;
  79         dump->regs.ds = current->thread.ds;
  80         dump->regs.es = current->thread.es;
  81         asm("movl %%fs,%0" : "=r" (fs)); dump->regs.fs = fs;
  82         asm("movl %%gs,%0" : "=r" (gs)); dump->regs.gs = gs;
  83         dump->regs.orig_eax = regs->orig_rax;
  84         dump->regs.eip = regs->rip;
  85         dump->regs.cs = regs->cs;
  86         dump->regs.eflags = regs->eflags;
  87         dump->regs.esp = regs->rsp;
  88         dump->regs.ss = regs->ss;
  89
  90 #if 1 /* FIXME */
  91         dump->u_fpvalid = 0;
  92 #else
  93         dump->u_fpvalid = dump_fpu (regs, &dump->i387);
  94 #endif
  95 }
  96
  97 #endif
  98
  99 static struct linux_binfmt aout_format = {
 100         .module         = THIS_MODULE,
 101         .load_binary    = load_aout_binary,
 102         .load_shlib     = load_aout_library,
 103 #ifdef CORE_DUMP
 104         .core_dump      = aout_core_dump,
 105 #endif
 106         .min_coredump   = PAGE_SIZE
 107 };
 108
 109 static void set_brk(unsigned long start, unsigned long end)
 110 {
 111         start = PAGE_ALIGN(start);
 112         end = PAGE_ALIGN(end);
 113         if (end <= start)
 114                 return;
 115         down_write(&current->mm->mmap_sem);
 116         do_brk(start, end - start);
 117         up_write(&current->mm->mmap_sem);
 118 }
 119
 120 #ifdef CORE_DUMP
 121 /*
 122  * These are the only things you should do on a core-file: use only these
 123  * macros to write out all the necessary info.
 124  */
 125
 126 static int dump_write(struct file *file, const void *addr, int nr)
 127 {
 128         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 129 }
 130
 131 #define DUMP_WRITE(addr, nr)    \
 132         if (!dump_write(file, (void *)(addr), (nr))) \
 133                 goto end_coredump;
 134
 135 #define DUMP_SEEK(offset) \
 136 if (file->f_op->llseek) { \
 137         if (file->f_op->llseek(file,(offset),0) != (offset)) \
 138                 goto end_coredump; \
 139 } else file->f_pos = (offset)
 140
 141 /*
 142  * Routine writes a core dump image in the current directory.
 143  * Currently only a stub-function.
 144  *
 145  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 146  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 147  * field, which also makes sure the core-dumps won't be recursive if the
 148  * dumping of the process results in another error..
 149  */
 150
 151 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
 152 {
 153         mm_segment_t fs;
 154         int has_dumped = 0;
 155         unsigned long dump_start, dump_size;
 156         struct user32 dump;
 157 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 158 #       define START_STACK(u)   (u.start_stack)
 159
 160         fs = get_fs();
 161         set_fs(KERNEL_DS);
 162         has_dumped = 1;
 163         current->flags |= PF_DUMPCORE;
 164         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 165         dump.u_ar0 = (u32)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 166         dump.signal = signr;
 167         dump_thread32(regs, &dump);
 168
 169 /* If the size of the dump file exceeds the rlimit, then see what would happen
 170    if we wrote the stack, but not the data area.  */
 171         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 172                 dump.u_dsize = 0;
 173
 174 /* Make sure we have enough room to write the stack and data areas. */
 175         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 176                 dump.u_ssize = 0;
 177
 178 /* make sure we actually have a data and stack area to dump */
 179         set_fs(USER_DS);
 180         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 181                 dump.u_dsize = 0;
 182         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 183                 dump.u_ssize = 0;
 184
 185         set_fs(KERNEL_DS);
 186 /* struct user */
 187         DUMP_WRITE(&dump,sizeof(dump));
 188 /* Now dump all of the user data.  Include malloced stuff as well */
 189         DUMP_SEEK(PAGE_SIZE);
 190 /* now we start writing out the user space info */
 191         set_fs(USER_DS);
 192 /* Dump the data area */
 193         if (dump.u_dsize != 0) {
 194                 dump_start = START_DATA(dump);
 195                 dump_size = dump.u_dsize << PAGE_SHIFT;
 196                 DUMP_WRITE(dump_start,dump_size);
 197         }
 198 /* Now prepare to dump the stack area */
 199         if (dump.u_ssize != 0) {
 200                 dump_start = START_STACK(dump);
 201                 dump_size = dump.u_ssize << PAGE_SHIFT;
 202                 DUMP_WRITE(dump_start,dump_size);
 203         }
 204 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 205         set_fs(KERNEL_DS);
 206         DUMP_WRITE(current,sizeof(*current));
 207 end_coredump:
 208         set_fs(fs);
 209         return has_dumped;
 210 }
 211 #endif
 212
 213 /*
 214  * create_aout_tables() parses the env- and arg-strings in new user
 215  * memory and creates the pointer tables from them, and puts their
 216  * addresses on the "stack", returning the new stack pointer value.
 217  */
 218 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 219 {
 220         u32 __user *argv;
 221         u32 __user *envp;
 222         u32 __user *sp;
 223         int argc = bprm->argc;
 224         int 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                 put_user((u32)(unsigned long)p,argv++);
 238                 do {
 239                         get_user(c,p++);
 240                 } while (c);
 241         }
 242         put_user(0, argv);
 243         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 244         while (envc-->0) {
 245                 char c;
 246                 put_user((u32)(unsigned long)p,envp++);
 247                 do {
 248                         get_user(c,p++);
 249                 } while (c);
 250         }
 251         put_user(0, envp);
 252         current->mm->env_end = (unsigned long) p;
 253         return sp;
 254 }
 255
 256 /*
 257  * These are the functions used to load a.out style executables and shared
 258  * libraries.  There is no binary dependent code anywhere else.
 259  */
 260
 261 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 262 {
 263         struct exec ex;
 264         unsigned long error;
 265         unsigned long fd_offset;
 266         unsigned long rlim;
 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(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 274                 return -ENOEXEC;
 275         }
 276
 277         fd_offset = N_TXTOFF(ex);
 278
 279         /* Check initial limits. This avoids letting people circumvent
 280          * size limits imposed on them by creating programs with large
 281          * arrays in the data or bss.
 282          */
 283         rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 284         if (rlim >= RLIM_INFINITY)
 285                 rlim = ~0;
 286         if (ex.a_data + ex.a_bss > rlim)
 287                 return -ENOMEM;
 288
 289         /* Flush all traces of the currently running executable */
 290         retval = flush_old_exec(bprm);
 291         if (retval)
 292                 return retval;
 293
 294         regs->cs = __USER32_CS;
 295         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 296                 regs->r13 = regs->r14 = regs->r15 = 0;
 297
 298         /* OK, This is the point of no return */
 299         set_personality(PER_LINUX);
 300         set_thread_flag(TIF_IA32);
 301         clear_thread_flag(TIF_ABI_PENDING);
 302
 303         current->mm->end_code = ex.a_text +
 304                 (current->mm->start_code = N_TXTADDR(ex));
 305         current->mm->end_data = ex.a_data +
 306                 (current->mm->start_data = N_DATADDR(ex));
 307         current->mm->brk = ex.a_bss +
 308                 (current->mm->start_brk = N_BSSADDR(ex));
 309         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 310         current->mm->cached_hole_size = 0;
 311
 312         current->mm->mmap = NULL;
 313         compute_creds(bprm);
 314         current->flags &= ~PF_FORKNOEXEC;
 315
 316         if (N_MAGIC(ex) == OMAGIC) {
 317                 unsigned long text_addr, map_size;
 318                 loff_t pos;
 319
 320                 text_addr = N_TXTADDR(ex);
 321
 322                 pos = 32;
 323                 map_size = ex.a_text+ex.a_data;
 324
 325                 down_write(&current->mm->mmap_sem);
 326                 error = do_brk(text_addr & PAGE_MASK, map_size);
 327                 up_write(&current->mm->mmap_sem);
 328
 329                 if (error != (text_addr & PAGE_MASK)) {
 330                         send_sig(SIGKILL, current, 0);
 331                         return error;
 332                 }
 333
 334                 error = bprm->file->f_op->read(bprm->file,
 335                          (char __user *)text_addr,
 336                           ex.a_text+ex.a_data, &pos);
 337                 if ((signed long)error < 0) {
 338                         send_sig(SIGKILL, current, 0);
 339                         return error;
 340                 }
 341
 342                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 343         } else {
 344 #ifdef WARN_OLD
 345                 static unsigned long error_time, error_time2;
 346                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 347                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 348                 {
 349                         printk(KERN_NOTICE "executable not page aligned\n");
 350                         error_time2 = jiffies;
 351                 }
 352
 353                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 354                     (jiffies-error_time) > 5*HZ)
 355                 {
 356                         printk(KERN_WARNING
 357                                "fd_offset is not page aligned. Please convert program: %s\n",
 358                                bprm->file->f_path.dentry->d_name.name);
 359                         error_time = jiffies;
 360                 }
 361 #endif
 362
 363                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 364                         loff_t pos = fd_offset;
 365                         down_write(&current->mm->mmap_sem);
 366                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 367                         up_write(&current->mm->mmap_sem);
 368                         bprm->file->f_op->read(bprm->file,
 369                                         (char __user *)N_TXTADDR(ex),
 370                                         ex.a_text+ex.a_data, &pos);
 371                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 372                                            (unsigned long) N_TXTADDR(ex) +
 373                                            ex.a_text+ex.a_data);
 374                         goto beyond_if;
 375                 }
 376
 377                 down_write(&current->mm->mmap_sem);
 378                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 379                         PROT_READ | PROT_EXEC,
 380                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 381                         fd_offset);
 382                 up_write(&current->mm->mmap_sem);
 383
 384                 if (error != N_TXTADDR(ex)) {
 385                         send_sig(SIGKILL, current, 0);
 386                         return error;
 387                 }
 388
 389                 down_write(&current->mm->mmap_sem);
 390                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 391                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 392                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 393                                 fd_offset + ex.a_text);
 394                 up_write(&current->mm->mmap_sem);
 395                 if (error != N_DATADDR(ex)) {
 396                         send_sig(SIGKILL, current, 0);
 397                         return error;
 398                 }
 399         }
 400 beyond_if:
 401         set_binfmt(&aout_format);
 402
 403         set_brk(current->mm->start_brk, current->mm->brk);
 404
 405         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 406         if (retval < 0) {
 407                 /* Someone check-me: is this error path enough? */
 408                 send_sig(SIGKILL, current, 0);
 409                 return retval;
 410         }
 411
 412         current->mm->start_stack =
 413                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 414         /* start thread */
 415         asm volatile("movl %0,%%fs" :: "r" (0)); \
 416         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 417         load_gs_index(0);
 418         (regs)->rip = ex.a_entry;
 419         (regs)->rsp = current->mm->start_stack;
 420         (regs)->eflags = 0x200;
 421         (regs)->cs = __USER32_CS;
 422         (regs)->ss = __USER32_DS;
 423         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 424         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 425         set_fs(USER_DS);
 426         if (unlikely(current->ptrace & PT_PTRACED)) {
 427                 if (current->ptrace & PT_TRACE_EXEC)
 428                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 429                 else
 430                         send_sig(SIGTRAP, current, 0);
 431         }
 432         return 0;
 433 }
 434
 435 static int load_aout_library(struct file *file)
 436 {
 437         struct inode * inode;
 438         unsigned long bss, start_addr, len;
 439         unsigned long 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) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 454                 goto out;
 455         }
 456
 457         if (N_FLAGS(ex))
 458                 goto out;
 459
 460         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 461            this off to get the starting address for the page */
 462
 463         start_addr =  ex.a_entry & 0xfffff000;
 464
 465         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 466                 loff_t pos = N_TXTOFF(ex);
 467
 468 #ifdef WARN_OLD
 469                 static unsigned long error_time;
 470                 if ((jiffies-error_time) > 5*HZ)
 471                 {
 472                         printk(KERN_WARNING
 473                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 474                                file->f_path.dentry->d_name.name);
 475                         error_time = jiffies;
 476                 }
 477 #endif
 478                 down_write(&current->mm->mmap_sem);
 479                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 480                 up_write(&current->mm->mmap_sem);
 481
 482                 file->f_op->read(file, (char __user *)start_addr,
 483                         ex.a_text + ex.a_data, &pos);
 484                 flush_icache_range((unsigned long) start_addr,
 485                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 486
 487                 retval = 0;
 488                 goto out;
 489         }
 490         /* Now use mmap to map the library into memory. */
 491         down_write(&current->mm->mmap_sem);
 492         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 493                         PROT_READ | PROT_WRITE | PROT_EXEC,
 494                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 495                         N_TXTOFF(ex));
 496         up_write(&current->mm->mmap_sem);
 497         retval = error;
 498         if (error != start_addr)
 499                 goto out;
 500
 501         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 502         bss = ex.a_text + ex.a_data + ex.a_bss;
 503         if (bss > len) {
 504                 down_write(&current->mm->mmap_sem);
 505                 error = do_brk(start_addr + len, bss - len);
 506                 up_write(&current->mm->mmap_sem);
 507                 retval = error;
 508                 if (error != start_addr + len)
 509                         goto out;
 510         }
 511         retval = 0;
 512 out:
 513         return retval;
 514 }
 515
 516 static int __init init_aout_binfmt(void)
 517 {
 518         return register_binfmt(&aout_format);
 519 }
 520
 521 static void __exit exit_aout_binfmt(void)
 522 {
 523         unregister_binfmt(&aout_format);
 524 }
 525
 526 module_init(init_aout_binfmt);
 527 module_exit(exit_aout_binfmt);
 528 MODULE_LICENSE("GPL");