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 #include <asm/ia32.h>
  35
  36 #undef WARN_OLD
  37 #undef CORE_DUMP /* probably broken */
  38
  39 extern int ia32_setup_arg_pages(struct linux_binprm *bprm,
  40                                 unsigned long stack_top, int exec_stack);
  41
  42 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  43 static int load_aout_library(struct file*);
  44
  45 #ifdef CORE_DUMP
  46 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
  47
  48 /*
  49  * fill in the user structure for a core dump..
  50  */
  51 static void dump_thread32(struct pt_regs * regs, struct user32 * dump)
  52 {
  53         u32 fs,gs;
  54
  55 /* changed the size calculations - should hopefully work better. lbt */
  56         dump->magic = CMAGIC;
  57         dump->start_code = 0;
  58         dump->start_stack = regs->rsp & ~(PAGE_SIZE - 1);
  59         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  60         dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  61         dump->u_dsize -= dump->u_tsize;
  62         dump->u_ssize = 0;
  63         dump->u_debugreg[0] = current->thread.debugreg0;
  64         dump->u_debugreg[1] = current->thread.debugreg1;
  65         dump->u_debugreg[2] = current->thread.debugreg2;
  66         dump->u_debugreg[3] = current->thread.debugreg3;
  67         dump->u_debugreg[4] = 0;
  68         dump->u_debugreg[5] = 0;
  69         dump->u_debugreg[6] = current->thread.debugreg6;
  70         dump->u_debugreg[7] = current->thread.debugreg7;
  71
  72         if (dump->start_stack < 0xc0000000)
  73                 dump->u_ssize = ((unsigned long) (0xc0000000 - dump->start_stack)) >> PAGE_SHIFT;
  74
  75         dump->regs.ebx = regs->rbx;
  76         dump->regs.ecx = regs->rcx;
  77         dump->regs.edx = regs->rdx;
  78         dump->regs.esi = regs->rsi;
  79         dump->regs.edi = regs->rdi;
  80         dump->regs.ebp = regs->rbp;
  81         dump->regs.eax = regs->rax;
  82         dump->regs.ds = current->thread.ds;
  83         dump->regs.es = current->thread.es;
  84         asm("movl %%fs,%0" : "=r" (fs)); dump->regs.fs = fs;
  85         asm("movl %%gs,%0" : "=r" (gs)); dump->regs.gs = gs;
  86         dump->regs.orig_eax = regs->orig_rax;
  87         dump->regs.eip = regs->rip;
  88         dump->regs.cs = regs->cs;
  89         dump->regs.eflags = regs->eflags;
  90         dump->regs.esp = regs->rsp;
  91         dump->regs.ss = regs->ss;
  92
  93 #if 1 /* FIXME */
  94         dump->u_fpvalid = 0;
  95 #else
  96         dump->u_fpvalid = dump_fpu (regs, &dump->i387);
  97 #endif
  98 }
  99
 100 #endif
 101
 102 static struct linux_binfmt aout_format = {
 103         .module         = THIS_MODULE,
 104         .load_binary    = load_aout_binary,
 105         .load_shlib     = load_aout_library,
 106 #ifdef CORE_DUMP
 107         .core_dump      = aout_core_dump,
 108 #endif
 109         .min_coredump   = PAGE_SIZE
 110 };
 111
 112 static void set_brk(unsigned long start, unsigned long end)
 113 {
 114         start = PAGE_ALIGN(start);
 115         end = PAGE_ALIGN(end);
 116         if (end <= start)
 117                 return;
 118         down_write(&current->mm->mmap_sem);
 119         do_brk(start, end - start);
 120         up_write(&current->mm->mmap_sem);
 121 }
 122
 123 #ifdef CORE_DUMP
 124 /*
 125  * These are the only things you should do on a core-file: use only these
 126  * macros to write out all the necessary info.
 127  */
 128
 129 static int dump_write(struct file *file, const void *addr, int nr)
 130 {
 131         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 132 }
 133
 134 #define DUMP_WRITE(addr, nr)    \
 135         if (!dump_write(file, (void *)(addr), (nr))) \
 136                 goto end_coredump;
 137
 138 #define DUMP_SEEK(offset) \
 139 if (file->f_op->llseek) { \
 140         if (file->f_op->llseek(file,(offset),0) != (offset)) \
 141                 goto end_coredump; \
 142 } else file->f_pos = (offset)
 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 {
 156         mm_segment_t fs;
 157         int has_dumped = 0;
 158         unsigned long dump_start, dump_size;
 159         struct user32 dump;
 160 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
 161 #       define START_STACK(u)   (u.start_stack)
 162
 163         fs = get_fs();
 164         set_fs(KERNEL_DS);
 165         has_dumped = 1;
 166         current->flags |= PF_DUMPCORE;
 167         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 168         dump.u_ar0 = (u32)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 169         dump.signal = signr;
 170         dump_thread32(regs, &dump);
 171
 172 /* If the size of the dump file exceeds the rlimit, then see what would happen
 173    if we wrote the stack, but not the data area.  */
 174         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 175             current->signal->rlim[RLIMIT_CORE].rlim_cur)
 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 >
 180             current->signal->rlim[RLIMIT_CORE].rlim_cur)
 181                 dump.u_ssize = 0;
 182
 183 /* make sure we actually have a data and stack area to dump */
 184         set_fs(USER_DS);
 185         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 186                 dump.u_dsize = 0;
 187         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 188                 dump.u_ssize = 0;
 189
 190         set_fs(KERNEL_DS);
 191 /* struct user */
 192         DUMP_WRITE(&dump,sizeof(dump));
 193 /* Now dump all of the user data.  Include malloced stuff as well */
 194         DUMP_SEEK(PAGE_SIZE);
 195 /* now we start writing out the user space info */
 196         set_fs(USER_DS);
 197 /* Dump the data area */
 198         if (dump.u_dsize != 0) {
 199                 dump_start = START_DATA(dump);
 200                 dump_size = dump.u_dsize << PAGE_SHIFT;
 201                 DUMP_WRITE(dump_start,dump_size);
 202         }
 203 /* Now prepare to dump the stack area */
 204         if (dump.u_ssize != 0) {
 205                 dump_start = START_STACK(dump);
 206                 dump_size = dump.u_ssize << PAGE_SHIFT;
 207                 DUMP_WRITE(dump_start,dump_size);
 208         }
 209 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 210         set_fs(KERNEL_DS);
 211         DUMP_WRITE(current,sizeof(*current));
 212 end_coredump:
 213         set_fs(fs);
 214         return has_dumped;
 215 }
 216 #endif
 217
 218 /*
 219  * create_aout_tables() parses the env- and arg-strings in new user
 220  * memory and creates the pointer tables from them, and puts their
 221  * addresses on the "stack", returning the new stack pointer value.
 222  */
 223 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 224 {
 225         u32 __user *argv;
 226         u32 __user *envp;
 227         u32 __user *sp;
 228         int argc = bprm->argc;
 229         int envc = bprm->envc;
 230
 231         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 232         sp -= envc+1;
 233         envp = sp;
 234         sp -= argc+1;
 235         argv = sp;
 236         put_user((unsigned long) envp,--sp);
 237         put_user((unsigned long) argv,--sp);
 238         put_user(argc,--sp);
 239         current->mm->arg_start = (unsigned long) p;
 240         while (argc-->0) {
 241                 char c;
 242                 put_user((u32)(unsigned long)p,argv++);
 243                 do {
 244                         get_user(c,p++);
 245                 } while (c);
 246         }
 247         put_user(NULL,argv);
 248         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 249         while (envc-->0) {
 250                 char c;
 251                 put_user((u32)(unsigned long)p,envp++);
 252                 do {
 253                         get_user(c,p++);
 254                 } while (c);
 255         }
 256         put_user(NULL,envp);
 257         current->mm->env_end = (unsigned long) p;
 258         return sp;
 259 }
 260
 261 /*
 262  * These are the functions used to load a.out style executables and shared
 263  * libraries.  There is no binary dependent code anywhere else.
 264  */
 265
 266 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 267 {
 268         struct exec ex;
 269         unsigned long error;
 270         unsigned long fd_offset;
 271         unsigned long rlim;
 272         int retval;
 273
 274         ex = *((struct exec *) bprm->buf);              /* exec-header */
 275         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 276              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 277             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 278             i_size_read(bprm->file->f_dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 279                 return -ENOEXEC;
 280         }
 281
 282         fd_offset = N_TXTOFF(ex);
 283
 284         /* Check initial limits. This avoids letting people circumvent
 285          * size limits imposed on them by creating programs with large
 286          * arrays in the data or bss.
 287          */
 288         rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 289         if (rlim >= RLIM_INFINITY)
 290                 rlim = ~0;
 291         if (ex.a_data + ex.a_bss > rlim)
 292                 return -ENOMEM;
 293
 294         /* Flush all traces of the currently running executable */
 295         retval = flush_old_exec(bprm);
 296         if (retval)
 297                 return retval;
 298
 299         regs->cs = __USER32_CS;
 300         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 301                 regs->r13 = regs->r14 = regs->r15 = 0;
 302
 303         /* OK, This is the point of no return */
 304         set_personality(PER_LINUX);
 305         set_thread_flag(TIF_IA32);
 306         clear_thread_flag(TIF_ABI_PENDING);
 307
 308         current->mm->end_code = ex.a_text +
 309                 (current->mm->start_code = N_TXTADDR(ex));
 310         current->mm->end_data = ex.a_data +
 311                 (current->mm->start_data = N_DATADDR(ex));
 312         current->mm->brk = ex.a_bss +
 313                 (current->mm->start_brk = N_BSSADDR(ex));
 314         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 315         current->mm->cached_hole_size = 0;
 316
 317         set_mm_counter(current->mm, rss, 0);
 318         current->mm->mmap = NULL;
 319         compute_creds(bprm);
 320         current->flags &= ~PF_FORKNOEXEC;
 321
 322         if (N_MAGIC(ex) == OMAGIC) {
 323                 unsigned long text_addr, map_size;
 324                 loff_t pos;
 325
 326                 text_addr = N_TXTADDR(ex);
 327
 328                 pos = 32;
 329                 map_size = ex.a_text+ex.a_data;
 330
 331                 down_write(&current->mm->mmap_sem);
 332                 error = do_brk(text_addr & PAGE_MASK, map_size);
 333                 up_write(&current->mm->mmap_sem);
 334
 335                 if (error != (text_addr & PAGE_MASK)) {
 336                         send_sig(SIGKILL, current, 0);
 337                         return error;
 338                 }
 339
 340                 error = bprm->file->f_op->read(bprm->file, (char *)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) && (jiffies-error_time2) > 5*HZ)
 353                 {
 354                         printk(KERN_NOTICE "executable not page aligned\n");
 355                         error_time2 = jiffies;
 356                 }
 357
 358                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 359                     (jiffies-error_time) > 5*HZ)
 360                 {
 361                         printk(KERN_WARNING
 362                                "fd_offset is not page aligned. Please convert program: %s\n",
 363                                bprm->file->f_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                         down_write(&current->mm->mmap_sem);
 371                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 372                         up_write(&current->mm->mmap_sem);
 373                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 374                                         ex.a_text+ex.a_data, &pos);
 375                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 376                                            (unsigned long) N_TXTADDR(ex) +
 377                                            ex.a_text+ex.a_data);
 378                         goto beyond_if;
 379                 }
 380
 381                 down_write(&current->mm->mmap_sem);
 382                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 383                         PROT_READ | PROT_EXEC,
 384                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 385                         fd_offset);
 386                 up_write(&current->mm->mmap_sem);
 387
 388                 if (error != N_TXTADDR(ex)) {
 389                         send_sig(SIGKILL, current, 0);
 390                         return error;
 391                 }
 392
 393                 down_write(&current->mm->mmap_sem);
 394                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 395                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 396                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE | MAP_32BIT,
 397                                 fd_offset + ex.a_text);
 398                 up_write(&current->mm->mmap_sem);
 399                 if (error != N_DATADDR(ex)) {
 400                         send_sig(SIGKILL, current, 0);
 401                         return error;
 402                 }
 403         }
 404 beyond_if:
 405         set_binfmt(&aout_format);
 406
 407         set_brk(current->mm->start_brk, current->mm->brk);
 408
 409         retval = ia32_setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 410         if (retval < 0) {
 411                 /* Someone check-me: is this error path enough? */
 412                 send_sig(SIGKILL, current, 0);
 413                 return retval;
 414         }
 415
 416         current->mm->start_stack =
 417                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 418         /* start thread */
 419         asm volatile("movl %0,%%fs" :: "r" (0)); \
 420         asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS));
 421         load_gs_index(0);
 422         (regs)->rip = ex.a_entry;
 423         (regs)->rsp = current->mm->start_stack;
 424         (regs)->eflags = 0x200;
 425         (regs)->cs = __USER32_CS;
 426         (regs)->ss = __USER32_DS;
 427         set_fs(USER_DS);
 428         if (unlikely(current->ptrace & PT_PTRACED)) {
 429                 if (current->ptrace & PT_TRACE_EXEC)
 430                         ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
 431                 else
 432                         send_sig(SIGTRAP, current, 0);
 433         }
 434         return 0;
 435 }
 436
 437 static int load_aout_library(struct file *file)
 438 {
 439         struct inode * inode;
 440         unsigned long bss, start_addr, len;
 441         unsigned long error;
 442         int retval;
 443         struct exec ex;
 444
 445         inode = file->f_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) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 456                 goto out;
 457         }
 458
 459         if (N_FLAGS(ex))
 460                 goto out;
 461
 462         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 463            this off to get the starting address for the page */
 464
 465         start_addr =  ex.a_entry & 0xfffff000;
 466
 467         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 468                 loff_t pos = N_TXTOFF(ex);
 469
 470 #ifdef WARN_OLD
 471                 static unsigned long error_time;
 472                 if ((jiffies-error_time) > 5*HZ)
 473                 {
 474                         printk(KERN_WARNING
 475                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 476                                file->f_dentry->d_name.name);
 477                         error_time = jiffies;
 478                 }
 479 #endif
 480                 down_write(&current->mm->mmap_sem);
 481                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 482                 up_write(&current->mm->mmap_sem);
 483
 484                 file->f_op->read(file, (char *)start_addr,
 485                         ex.a_text + ex.a_data, &pos);
 486                 flush_icache_range((unsigned long) start_addr,
 487                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 488
 489                 retval = 0;
 490                 goto out;
 491         }
 492         /* Now use mmap to map the library into memory. */
 493         down_write(&current->mm->mmap_sem);
 494         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 495                         PROT_READ | PROT_WRITE | PROT_EXEC,
 496                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 497                         N_TXTOFF(ex));
 498         up_write(&current->mm->mmap_sem);
 499         retval = error;
 500         if (error != start_addr)
 501                 goto out;
 502
 503         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 504         bss = ex.a_text + ex.a_data + ex.a_bss;
 505         if (bss > len) {
 506                 down_write(&current->mm->mmap_sem);
 507                 error = do_brk(start_addr + len, bss - len);
 508                 up_write(&current->mm->mmap_sem);
 509                 retval = error;
 510                 if (error != start_addr + len)
 511                         goto out;
 512         }
 513         retval = 0;
 514 out:
 515         return retval;
 516 }
 517
 518 static int __init init_aout_binfmt(void)
 519 {
 520         return register_binfmt(&aout_format);
 521 }
 522
 523 static void __exit exit_aout_binfmt(void)
 524 {
 525         unregister_binfmt(&aout_format);
 526 }
 527
 528 module_init(init_aout_binfmt);
 529 module_exit(exit_aout_binfmt);
 530 MODULE_LICENSE("GPL");