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
  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
  35 #undef WARN_OLD
  36 #undef CORE_DUMP /* probably broken */
  37
  38 extern int ia32_setup_arg_pages(struct linux_binprm *bprm, int exec_stack);
  39
  40 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  41 static int load_aout_library(struct file*);
  42
  43 #if 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 #if 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         do_brk(start, end - start);
 117 }
 118
 119 #if CORE_DUMP
 120 /*
 121  * These are the only things you should do on a core-file: use only these
 122  * macros to write out all the necessary info.
 123  */
 124
 125 static int dump_write(struct file *file, const void *addr, int nr)
 126 {
 127         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 128 }
 129
 130 #define DUMP_WRITE(addr, nr)    \
 131         if (!dump_write(file, (void *)(addr), (nr))) \
 132                 goto end_coredump;
 133
 134 #define DUMP_SEEK(offset) \
 135 if (file->f_op->llseek) { \
 136         if (file->f_op->llseek(file,(offset),0) != (offset)) \
 137                 goto end_coredump; \
 138 } else file->f_pos = (offset)
 139
 140 /*
 141  * Routine writes a core dump image in the current directory.
 142  * Currently only a stub-function.
 143  *
 144  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 145  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 146  * field, which also makes sure the core-dumps won't be recursive if the
 147  * dumping of the process results in another error..
 148  */
 149
 150 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
 151 {
 152         mm_segment_t fs;
 153         int has_dumped = 0;
 154         unsigned long dump_start, dump_size;
 155         struct user32 dump;
 156 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 157 #       define START_STACK(u)   (u.start_stack)
 158
 159         fs = get_fs();
 160         set_fs(KERNEL_DS);
 161         has_dumped = 1;
 162         current->flags |= PF_DUMPCORE;
 163         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 164         dump.u_ar0 = (u32)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 165         dump.signal = signr;
 166         dump_thread32(regs, &dump);
 167
 168 /* If the size of the dump file exceeds the rlimit, then see what would happen
 169    if we wrote the stack, but not the data area.  */
 170         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 171             current->rlim[RLIMIT_CORE].rlim_cur)
 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 >
 176             current->rlim[RLIMIT_CORE].rlim_cur)
 177                 dump.u_ssize = 0;
 178
 179 /* make sure we actually have a data and stack area to dump */
 180         set_fs(USER_DS);
 181         if (verify_area(VERIFY_READ, (void *) (unsigned long)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 182                 dump.u_dsize = 0;
 183         if (verify_area(VERIFY_READ, (void *) (unsigned long)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 184                 dump.u_ssize = 0;
 185
 186         set_fs(KERNEL_DS);
 187 /* struct user */
 188         DUMP_WRITE(&dump,sizeof(dump));
 189 /* Now dump all of the user data.  Include malloced stuff as well */
 190         DUMP_SEEK(PAGE_SIZE);
 191 /* now we start writing out the user space info */
 192         set_fs(USER_DS);
 193 /* Dump the data area */
 194         if (dump.u_dsize != 0) {
 195                 dump_start = START_DATA(dump);
 196                 dump_size = dump.u_dsize << PAGE_SHIFT;
 197                 DUMP_WRITE(dump_start,dump_size);
 198         }
 199 /* Now prepare to dump the stack area */
 200         if (dump.u_ssize != 0) {
 201                 dump_start = START_STACK(dump);
 202                 dump_size = dump.u_ssize << PAGE_SHIFT;
 203                 DUMP_WRITE(dump_start,dump_size);
 204         }
 205 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 206         set_fs(KERNEL_DS);
 207         DUMP_WRITE(current,sizeof(*current));
 208 end_coredump:
 209         set_fs(fs);
 210         return has_dumped;
 211 }
 212 #endif
 213
 214 /*
 215  * create_aout_tables() parses the env- and arg-strings in new user
 216  * memory and creates the pointer tables from them, and puts their
 217  * addresses on the "stack", returning the new stack pointer value.
 218  */
 219 static u32 * create_aout_tables(char * p, struct linux_binprm * bprm)
 220 {
 221         u32 *argv, *envp;
 222         u32 * sp;
 223         int argc = bprm->argc;
 224         int envc = bprm->envc;
 225
 226         sp = (u32 *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 227         sp -= envc+1;
 228         envp = (u32 *) sp;
 229         sp -= argc+1;
 230         argv = (u32 *) 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(NULL,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(NULL,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_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->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
 311         current->mm->rss = 0;
 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                 error = do_brk(text_addr & PAGE_MASK, map_size);
 326                 if (error != (text_addr & PAGE_MASK)) {
 327                         send_sig(SIGKILL, current, 0);
 328                         return error;
 329                 }
 330
 331                 error = bprm->file->f_op->read(bprm->file, (char *)text_addr,
 332                           ex.a_text+ex.a_data, &pos);
 333                 if ((signed long)error < 0) {
 334                         send_sig(SIGKILL, current, 0);
 335                         return error;
 336                 }
 337
 338                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 339         } else {
 340 #ifdef WARN_OLD
 341                 static unsigned long error_time, error_time2;
 342                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 343                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 344                 {
 345                         printk(KERN_NOTICE "executable not page aligned\n");
 346                         error_time2 = jiffies;
 347                 }
 348
 349                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 350                     (jiffies-error_time) > 5*HZ)
 351                 {
 352                         printk(KERN_WARNING
 353                                "fd_offset is not page aligned. Please convert program: %s\n",
 354                                bprm->file->f_dentry->d_name.name);
 355                         error_time = jiffies;
 356                 }
 357 #endif
 358
 359                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 360                         loff_t pos = fd_offset;
 361                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 362                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 363                                         ex.a_text+ex.a_data, &pos);
 364                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 365                                            (unsigned long) N_TXTADDR(ex) +
 366                                            ex.a_text+ex.a_data);
 367                         goto beyond_if;
 368                 }
 369
 370                 down_write(&current->mm->mmap_sem);
 371                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 372                         PROT_READ | PROT_EXEC,
 373                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 374                         fd_offset);
 375                 up_write(&current->mm->mmap_sem);
 376
 377                 if (error != N_TXTADDR(ex)) {
 378                         send_sig(SIGKILL, current, 0);
 379                         return error;
 380                 }
 381
 382                 down_write(&current->mm->mmap_sem);
 383                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 384                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 385                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 386                                 fd_offset + ex.a_text);
 387                 up_write(&current->mm->mmap_sem);
 388                 if (error != N_DATADDR(ex)) {
 389                         send_sig(SIGKILL, current, 0);
 390                         return error;
 391                 }
 392         }
 393 beyond_if:
 394         set_binfmt(&aout_format);
 395
 396         set_brk(current->mm->start_brk, current->mm->brk);
 397
 398         retval = ia32_setup_arg_pages(bprm, EXSTACK_DEFAULT);
 399         if (retval < 0) {
 400                 /* Someone check-me: is this error path enough? */
 401                 send_sig(SIGKILL, current, 0);
 402                 return retval;
 403         }
 404
 405         current->mm->start_stack =
 406                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 407         /* start thread */
 408         asm volatile("movl %0,%%fs" :: "r" (0)); \
 409         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 410         load_gs_index(0);
 411         (regs)->rip = ex.a_entry;
 412         (regs)->rsp = current->mm->start_stack;
 413         (regs)->eflags = 0x200;
 414         (regs)->cs = __USER32_CS;
 415         (regs)->ss = __USER32_DS;
 416         set_fs(USER_DS);
 417         if (unlikely(current->ptrace & PT_PTRACED)) {
 418                 if (current->ptrace & PT_TRACE_EXEC)
 419                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 420                 else
 421                         send_sig(SIGTRAP, current, 0);
 422         }
 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;
 430         unsigned long error;
 431         int retval;
 432         struct exec ex;
 433
 434         inode = file->f_dentry->d_inode;
 435
 436         retval = -ENOEXEC;
 437         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 438         if (error != sizeof(ex))
 439                 goto out;
 440
 441         /* We come in here for the regular a.out style of shared libraries */
 442         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 443             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 444             i_size_read(inode) < 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 ((jiffies-error_time) > 5*HZ)
 462                 {
 463                         printk(KERN_WARNING
 464                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 465                                file->f_dentry->d_name.name);
 466                         error_time = jiffies;
 467                 }
 468 #endif
 469
 470                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 471
 472                 file->f_op->read(file, (char *)start_addr,
 473                         ex.a_text + ex.a_data, &pos);
 474                 flush_icache_range((unsigned long) start_addr,
 475                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 476
 477                 retval = 0;
 478                 goto out;
 479         }
 480         /* Now use mmap to map the library into memory. */
 481         down_write(&current->mm->mmap_sem);
 482         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 483                         PROT_READ | PROT_WRITE | PROT_EXEC,
 484                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 485                         N_TXTOFF(ex));
 486         up_write(&current->mm->mmap_sem);
 487         retval = error;
 488         if (error != start_addr)
 489                 goto out;
 490
 491         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 492         bss = ex.a_text + ex.a_data + ex.a_bss;
 493         if (bss > len) {
 494                 error = do_brk(start_addr + len, bss - len);
 495                 retval = error;
 496                 if (error != start_addr + len)
 497                         goto out;
 498         }
 499         retval = 0;
 500 out:
 501         return retval;
 502 }
 503
 504 static int __init init_aout_binfmt(void)
 505 {
 506         return register_binfmt(&aout_format);
 507 }
 508
 509 static void __exit exit_aout_binfmt(void)
 510 {
 511         unregister_binfmt(&aout_format);
 512 }
 513
 514 module_init(init_aout_binfmt);
 515 module_exit(exit_aout_binfmt);
 516 MODULE_LICENSE("GPL");