arch/x86_64/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 #include <linux/vs_memory.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/user32.h>
  35 #include <asm/ia32.h>
  36
  37 #undef WARN_OLD
  38 #undef CORE_DUMP /* probably broken */
  39
  40 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  41 static int load_aout_library(struct file*);
  42
  43 #ifdef CORE_DUMP
  44 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
  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->rsp & ~(PAGE_SIZE - 1);
  57         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  58         dump->u_dsize = ((unsigned long) (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                 dump->u_ssize = ((unsigned long) (0xc0000000 - dump->start_stack)) >> PAGE_SHIFT;
  72
  73         dump->regs.ebx = regs->rbx;
  74         dump->regs.ecx = regs->rcx;
  75         dump->regs.edx = regs->rdx;
  76         dump->regs.esi = regs->rsi;
  77         dump->regs.edi = regs->rdi;
  78         dump->regs.ebp = regs->rbp;
  79         dump->regs.eax = regs->rax;
  80         dump->regs.ds = current->thread.ds;
  81         dump->regs.es = current->thread.es;
  82         asm("movl %%fs,%0" : "=r" (fs)); dump->regs.fs = fs;
  83         asm("movl %%gs,%0" : "=r" (gs)); dump->regs.gs = gs;
  84         dump->regs.orig_eax = regs->orig_rax;
  85         dump->regs.eip = regs->rip;
  86         dump->regs.cs = regs->cs;
  87         dump->regs.eflags = regs->eflags;
  88         dump->regs.esp = regs->rsp;
  89         dump->regs.ss = regs->ss;
  90
  91 #if 1 /* FIXME */
  92         dump->u_fpvalid = 0;
  93 #else
  94         dump->u_fpvalid = dump_fpu (regs, &dump->i387);
  95 #endif
  96 }
  97
  98 #endif
  99
 100 static struct linux_binfmt aout_format = {
 101         .module         = THIS_MODULE,
 102         .load_binary    = load_aout_binary,
 103         .load_shlib     = load_aout_library,
 104 #ifdef CORE_DUMP
 105         .core_dump      = aout_core_dump,
 106 #endif
 107         .min_coredump   = PAGE_SIZE
 108 };
 109
 110 static void set_brk(unsigned long start, unsigned long end)
 111 {
 112         start = PAGE_ALIGN(start);
 113         end = PAGE_ALIGN(end);
 114         if (end <= start)
 115                 return;
 116         down_write(&current->mm->mmap_sem);
 117         do_brk(start, end - start);
 118         up_write(&current->mm->mmap_sem);
 119 }
 120
 121 #ifdef CORE_DUMP
 122 /*
 123  * These are the only things you should do on a core-file: use only these
 124  * macros to write out all the necessary info.
 125  */
 126
 127 static int dump_write(struct file *file, const void *addr, int nr)
 128 {
 129         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 130 }
 131
 132 #define DUMP_WRITE(addr, nr)    \
 133         if (!dump_write(file, (void *)(addr), (nr))) \
 134                 goto end_coredump;
 135
 136 #define DUMP_SEEK(offset) \
 137 if (file->f_op->llseek) { \
 138         if (file->f_op->llseek(file,(offset),0) != (offset)) \
 139                 goto end_coredump; \
 140 } else file->f_pos = (offset)
 141
 142 /*
 143  * Routine writes a core dump image in the current directory.
 144  * Currently only a stub-function.
 145  *
 146  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 147  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 148  * field, which also makes sure the core-dumps won't be recursive if the
 149  * dumping of the process results in another error..
 150  */
 151
 152 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
 153 {
 154         mm_segment_t fs;
 155         int has_dumped = 0;
 156         unsigned long dump_start, dump_size;
 157         struct user32 dump;
 158 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 159 #       define START_STACK(u)   (u.start_stack)
 160
 161         fs = get_fs();
 162         set_fs(KERNEL_DS);
 163         has_dumped = 1;
 164         current->flags |= PF_DUMPCORE;
 165         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 166         dump.u_ar0 = (u32)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 167         dump.signal = signr;
 168         dump_thread32(regs, &dump);
 169
 170 /* If the size of the dump file exceeds the rlimit, then see what would happen
 171    if we wrote the stack, but not the data area.  */
 172         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 173             current->signal->rlim[RLIMIT_CORE].rlim_cur)
 174                 dump.u_dsize = 0;
 175
 176 /* Make sure we have enough room to write the stack and data areas. */
 177         if ((dump.u_ssize+1) * PAGE_SIZE >
 178             current->signal->rlim[RLIMIT_CORE].rlim_cur)
 179                 dump.u_ssize = 0;
 180
 181 /* make sure we actually have a data and stack area to dump */
 182         set_fs(USER_DS);
 183         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 184                 dump.u_dsize = 0;
 185         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 186                 dump.u_ssize = 0;
 187
 188         set_fs(KERNEL_DS);
 189 /* struct user */
 190         DUMP_WRITE(&dump,sizeof(dump));
 191 /* Now dump all of the user data.  Include malloced stuff as well */
 192         DUMP_SEEK(PAGE_SIZE);
 193 /* now we start writing out the user space info */
 194         set_fs(USER_DS);
 195 /* Dump the data area */
 196         if (dump.u_dsize != 0) {
 197                 dump_start = START_DATA(dump);
 198                 dump_size = dump.u_dsize << PAGE_SHIFT;
 199                 DUMP_WRITE(dump_start,dump_size);
 200         }
 201 /* Now prepare to dump the stack area */
 202         if (dump.u_ssize != 0) {
 203                 dump_start = START_STACK(dump);
 204                 dump_size = dump.u_ssize << PAGE_SHIFT;
 205                 DUMP_WRITE(dump_start,dump_size);
 206         }
 207 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 208         set_fs(KERNEL_DS);
 209         DUMP_WRITE(current,sizeof(*current));
 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;
 224         u32 __user *envp;
 225         u32 __user *sp;
 226         int argc = bprm->argc;
 227         int 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                 put_user((u32)(unsigned long)p,argv++);
 241                 do {
 242                         get_user(c,p++);
 243                 } while (c);
 244         }
 245         put_user(NULL,argv);
 246         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 247         while (envc-->0) {
 248                 char c;
 249                 put_user((u32)(unsigned long)p,envp++);
 250                 do {
 251                         get_user(c,p++);
 252                 } while (c);
 253         }
 254         put_user(NULL,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
 264 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 265 {
 266         struct exec ex;
 267         unsigned long error;
 268         unsigned long fd_offset;
 269         unsigned long rlim;
 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_dentry->d_inode) < 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 = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 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         regs->cs = __USER32_CS;
 298         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 299                 regs->r13 = regs->r14 = regs->r15 = 0;
 300
 301         /* OK, This is the point of no return */
 302         set_personality(PER_LINUX);
 303         set_thread_flag(TIF_IA32);
 304         clear_thread_flag(TIF_ABI_PENDING);
 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         current->mm->mmap = NULL;
 316         compute_creds(bprm);
 317         current->flags &= ~PF_FORKNOEXEC;
 318
 319         if (N_MAGIC(ex) == OMAGIC) {
 320                 unsigned long text_addr, map_size;
 321                 loff_t pos;
 322
 323                 text_addr = N_TXTADDR(ex);
 324
 325                 pos = 32;
 326                 map_size = ex.a_text+ex.a_data;
 327
 328                 down_write(&current->mm->mmap_sem);
 329                 error = do_brk(text_addr & PAGE_MASK, map_size);
 330                 up_write(&current->mm->mmap_sem);
 331
 332                 if (error != (text_addr & PAGE_MASK)) {
 333                         send_sig(SIGKILL, current, 0);
 334                         return error;
 335                 }
 336
 337                 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
 338                           ex.a_text+ex.a_data, &pos);
 339                 if ((signed long)error < 0) {
 340                         send_sig(SIGKILL, current, 0);
 341                         return error;
 342                 }
 343
 344                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 345         } else {
 346 #ifdef WARN_OLD
 347                 static unsigned long error_time, error_time2;
 348                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 349                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 350                 {
 351                         printk(KERN_NOTICE "executable not page aligned\n");
 352                         error_time2 = jiffies;
 353                 }
 354
 355                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 356                     (jiffies-error_time) > 5*HZ)
 357                 {
 358                         printk(KERN_WARNING
 359                                "fd_offset is not page aligned. Please convert program: %s\n",
 360                                bprm->file->f_dentry->d_name.name);
 361                         error_time = jiffies;
 362                 }
 363 #endif
 364
 365                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 366                         loff_t pos = fd_offset;
 367                         down_write(&current->mm->mmap_sem);
 368                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 369                         up_write(&current->mm->mmap_sem);
 370                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 371                                         ex.a_text+ex.a_data, &pos);
 372                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 373                                            (unsigned long) N_TXTADDR(ex) +
 374                                            ex.a_text+ex.a_data);
 375                         goto beyond_if;
 376                 }
 377
 378                 down_write(&current->mm->mmap_sem);
 379                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 380                         PROT_READ | PROT_EXEC,
 381                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 382                         fd_offset);
 383                 up_write(&current->mm->mmap_sem);
 384
 385                 if (error != N_TXTADDR(ex)) {
 386                         send_sig(SIGKILL, current, 0);
 387                         return error;
 388                 }
 389
 390                 down_write(&current->mm->mmap_sem);
 391                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 392                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 393                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 394                                 fd_offset + ex.a_text);
 395                 up_write(&current->mm->mmap_sem);
 396                 if (error != N_DATADDR(ex)) {
 397                         send_sig(SIGKILL, current, 0);
 398                         return error;
 399                 }
 400         }
 401 beyond_if:
 402         set_binfmt(&aout_format);
 403
 404         set_brk(current->mm->start_brk, current->mm->brk);
 405
 406         retval = ia32_setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 407         if (retval < 0) {
 408                 /* Someone check-me: is this error path enough? */
 409                 send_sig(SIGKILL, current, 0);
 410                 return retval;
 411         }
 412
 413         current->mm->start_stack =
 414                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 415         /* start thread */
 416         asm volatile("movl %0,%%fs" :: "r" (0)); \
 417         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 418         load_gs_index(0);
 419         (regs)->rip = ex.a_entry;
 420         (regs)->rsp = current->mm->start_stack;
 421         (regs)->eflags = 0x200;
 422         (regs)->cs = __USER32_CS;
 423         (regs)->ss = __USER32_DS;
 424         set_fs(USER_DS);
 425         return 0;
 426 }
 427
 428 static int load_aout_library(struct file *file)
 429 {
 430         struct inode * inode;
 431         unsigned long bss, start_addr, len;
 432         unsigned long error;
 433         int retval;
 434         struct exec ex;
 435
 436         inode = file->f_dentry->d_inode;
 437
 438         retval = -ENOEXEC;
 439         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 440         if (error != sizeof(ex))
 441                 goto out;
 442
 443         /* We come in here for the regular a.out style of shared libraries */
 444         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 445             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 446             i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 447                 goto out;
 448         }
 449
 450         if (N_FLAGS(ex))
 451                 goto out;
 452
 453         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 454            this off to get the starting address for the page */
 455
 456         start_addr =  ex.a_entry & 0xfffff000;
 457
 458         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 459                 loff_t pos = N_TXTOFF(ex);
 460
 461 #ifdef WARN_OLD
 462                 static unsigned long error_time;
 463                 if ((jiffies-error_time) > 5*HZ)
 464                 {
 465                         printk(KERN_WARNING
 466                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 467                                file->f_dentry->d_name.name);
 468                         error_time = jiffies;
 469                 }
 470 #endif
 471                 down_write(&current->mm->mmap_sem);
 472                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 473                 up_write(&current->mm->mmap_sem);
 474
 475                 file->f_op->read(file, (char *)start_addr,
 476                         ex.a_text + ex.a_data, &pos);
 477                 flush_icache_range((unsigned long) start_addr,
 478                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 479
 480                 retval = 0;
 481                 goto out;
 482         }
 483         /* Now use mmap to map the library into memory. */
 484         down_write(&current->mm->mmap_sem);
 485         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 486                         PROT_READ | PROT_WRITE | PROT_EXEC,
 487                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 488                         N_TXTOFF(ex));
 489         up_write(&current->mm->mmap_sem);
 490         retval = error;
 491         if (error != start_addr)
 492                 goto out;
 493
 494         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 495         bss = ex.a_text + ex.a_data + ex.a_bss;
 496         if (bss > len) {
 497                 down_write(&current->mm->mmap_sem);
 498                 error = do_brk(start_addr + len, bss - len);
 499                 up_write(&current->mm->mmap_sem);
 500                 retval = error;
 501                 if (error != start_addr + len)
 502                         goto out;
 503         }
 504         retval = 0;
 505 out:
 506         return retval;
 507 }
 508
 509 static int __init init_aout_binfmt(void)
 510 {
 511         return register_binfmt(&aout_format);
 512 }
 513
 514 static void __exit exit_aout_binfmt(void)
 515 {
 516         unregister_binfmt(&aout_format);
 517 }
 518
 519 module_init(init_aout_binfmt);
 520 module_exit(exit_aout_binfmt);
 521 MODULE_LICENSE("GPL");