kernel/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 #include <linux/perf_event.h>
  29
  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
  38 static int load_aout_binary(struct linux_binprm *);
  39 static int load_aout_library(struct file *);
  40
  41 #ifdef CONFIG_COREDUMP
  42 static int aout_core_dump(struct coredump_params *);
  43
  44 static unsigned long get_dr(int n)
  45 {
  46         struct perf_event *bp = current->thread.ptrace_bps[n];
  47         return bp ? bp->hw.info.address : 0;
  48 }
  49
  50 /*
  51  * fill in the user structure for a core dump..
  52  */
  53 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  54 {
  55         u32 fs, gs;
  56         memset(dump, 0, sizeof(*dump));
  57
  58 /* changed the size calculations - should hopefully work better. lbt */
  59         dump->magic = CMAGIC;
  60         dump->start_code = 0;
  61         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  62         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  63         dump->u_dsize = ((unsigned long)
  64                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  65         dump->u_dsize -= dump->u_tsize;
  66         dump->u_debugreg[0] = get_dr(0);
  67         dump->u_debugreg[1] = get_dr(1);
  68         dump->u_debugreg[2] = get_dr(2);
  69         dump->u_debugreg[3] = get_dr(3);
  70         dump->u_debugreg[6] = current->thread.debugreg6;
  71         dump->u_debugreg[7] = current->thread.ptrace_dr7;
  72
  73         if (dump->start_stack < 0xc0000000) {
  74                 unsigned long tmp;
  75
  76                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  77                 dump->u_ssize = tmp >> PAGE_SHIFT;
  78         }
  79
  80         dump->regs.ebx = regs->bx;
  81         dump->regs.ecx = regs->cx;
  82         dump->regs.edx = regs->dx;
  83         dump->regs.esi = regs->si;
  84         dump->regs.edi = regs->di;
  85         dump->regs.ebp = regs->bp;
  86         dump->regs.eax = regs->ax;
  87         dump->regs.ds = current->thread.ds;
  88         dump->regs.es = current->thread.es;
  89         savesegment(fs, fs);
  90         dump->regs.fs = fs;
  91         savesegment(gs, gs);
  92         dump->regs.gs = gs;
  93         dump->regs.orig_eax = regs->orig_ax;
  94         dump->regs.eip = regs->ip;
  95         dump->regs.cs = regs->cs;
  96         dump->regs.eflags = regs->flags;
  97         dump->regs.esp = regs->sp;
  98         dump->regs.ss = regs->ss;
  99
 100 #if 1 /* FIXME */
 101         dump->u_fpvalid = 0;
 102 #else
 103         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 104 #endif
 105 }
 106
 107 #endif
 108
 109 static struct linux_binfmt aout_format = {
 110         .module         = THIS_MODULE,
 111         .load_binary    = load_aout_binary,
 112         .load_shlib     = load_aout_library,
 113 #ifdef CONFIG_COREDUMP
 114         .core_dump      = aout_core_dump,
 115 #endif
 116         .min_coredump   = PAGE_SIZE
 117 };
 118
 119 static void set_brk(unsigned long start, unsigned long end)
 120 {
 121         start = PAGE_ALIGN(start);
 122         end = PAGE_ALIGN(end);
 123         if (end <= start)
 124                 return;
 125         vm_brk(start, end - start);
 126 }
 127
 128 #ifdef CONFIG_COREDUMP
 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 START_DATA(u)   (u.u_tsize << PAGE_SHIFT)
 137 #define START_STACK(u)  (u.start_stack)
 138
 139 /*
 140  * Routine writes a core dump image in the current directory.
 141  * Currently only a stub-function.
 142  *
 143  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 144  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 145  * field, which also makes sure the core-dumps won't be recursive if the
 146  * dumping of the process results in another error..
 147  */
 148
 149 static int aout_core_dump(struct coredump_params *cprm)
 150 {
 151         mm_segment_t fs;
 152         int has_dumped = 0;
 153         unsigned long dump_start, dump_size;
 154         struct user32 dump;
 155
 156         fs = get_fs();
 157         set_fs(KERNEL_DS);
 158         has_dumped = 1;
 159         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 160         dump.u_ar0 = offsetof(struct user32, regs);
 161         dump.signal = cprm->siginfo->si_signo;
 162         dump_thread32(cprm->regs, &dump);
 163
 164         /*
 165          * If the size of the dump file exceeds the rlimit, then see
 166          * what would happen if we wrote the stack, but not the data
 167          * area.
 168          */
 169         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
 170                 dump.u_dsize = 0;
 171
 172         /* Make sure we have enough room to write the stack and data areas. */
 173         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
 174                 dump.u_ssize = 0;
 175
 176         /* make sure we actually have a data and stack area to dump */
 177         set_fs(USER_DS);
 178         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 179                        dump.u_dsize << PAGE_SHIFT))
 180                 dump.u_dsize = 0;
 181         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 182                        dump.u_ssize << PAGE_SHIFT))
 183                 dump.u_ssize = 0;
 184
 185         set_fs(KERNEL_DS);
 186         /* struct user */
 187         if (!dump_emit(cprm, &dump, sizeof(dump)))
 188                 goto end_coredump;
 189         /* Now dump all of the user data.  Include malloced stuff as well */
 190         if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
 191                 goto end_coredump;
 192         /* now we start writing out the user space info */
 193         set_fs(USER_DS);
 194         /* Dump the data area */
 195         if (dump.u_dsize != 0) {
 196                 dump_start = START_DATA(dump);
 197                 dump_size = dump.u_dsize << PAGE_SHIFT;
 198                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 199                         goto end_coredump;
 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                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 206                         goto end_coredump;
 207         }
 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 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 220 {
 221         u32 __user *argv, *envp, *sp;
 222         int argc = bprm->argc, envc = bprm->envc;
 223
 224         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 225         sp -= envc+1;
 226         envp = sp;
 227         sp -= argc+1;
 228         argv = sp;
 229         put_user((unsigned long) envp, --sp);
 230         put_user((unsigned long) argv, --sp);
 231         put_user(argc, --sp);
 232         current->mm->arg_start = (unsigned long) p;
 233         while (argc-- > 0) {
 234                 char c;
 235
 236                 put_user((u32)(unsigned long)p, argv++);
 237                 do {
 238                         get_user(c, p++);
 239                 } while (c);
 240         }
 241         put_user(0, argv);
 242         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 243         while (envc-- > 0) {
 244                 char c;
 245
 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 static int load_aout_binary(struct linux_binprm *bprm)
 261 {
 262         unsigned long error, fd_offset, rlim;
 263         struct pt_regs *regs = current_pt_regs();
 264         struct exec ex;
 265         int retval;
 266
 267         ex = *((struct exec *) bprm->buf);              /* exec-header */
 268         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 269              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 270             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 271             i_size_read(file_inode(bprm->file)) <
 272             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 273                 return -ENOEXEC;
 274         }
 275
 276         fd_offset = N_TXTOFF(ex);
 277
 278         /* Check initial limits. This avoids letting people circumvent
 279          * size limits imposed on them by creating programs with large
 280          * arrays in the data or bss.
 281          */
 282         rlim = rlimit(RLIMIT_DATA);
 283         if (rlim >= RLIM_INFINITY)
 284                 rlim = ~0;
 285         if (ex.a_data + ex.a_bss > rlim)
 286                 return -ENOMEM;
 287
 288         /* Flush all traces of the currently running executable */
 289         retval = flush_old_exec(bprm);
 290         if (retval)
 291                 return retval;
 292
 293         /* OK, This is the point of no return */
 294         set_personality(PER_LINUX);
 295         set_personality_ia32(false);
 296
 297         setup_new_exec(bprm);
 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         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
 310         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 311         if (retval < 0)
 312                 return retval;
 313
 314         install_exec_creds(bprm);
 315
 316         if (N_MAGIC(ex) == OMAGIC) {
 317                 unsigned long text_addr, map_size;
 318
 319                 text_addr = N_TXTADDR(ex);
 320                 map_size = ex.a_text+ex.a_data;
 321
 322                 error = vm_brk(text_addr & PAGE_MASK, map_size);
 323
 324                 if (error != (text_addr & PAGE_MASK))
 325                         return error;
 326
 327                 error = read_code(bprm->file, text_addr, 32,
 328                                   ex.a_text + ex.a_data);
 329                 if ((signed long)error < 0)
 330                         return error;
 331         } else {
 332 #ifdef WARN_OLD
 333                 static unsigned long error_time, error_time2;
 334                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 335                     (N_MAGIC(ex) != NMAGIC) &&
 336                                 time_after(jiffies, error_time2 + 5*HZ)) {
 337                         printk(KERN_NOTICE "executable not page aligned\n");
 338                         error_time2 = jiffies;
 339                 }
 340
 341                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 342                             time_after(jiffies, error_time + 5*HZ)) {
 343                         printk(KERN_WARNING
 344                                "fd_offset is not page aligned. Please convert "
 345                                "program: %pD\n",
 346                                bprm->file);
 347                         error_time = jiffies;
 348                 }
 349 #endif
 350
 351                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 352                         vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 353                         read_code(bprm->file, N_TXTADDR(ex), fd_offset,
 354                                         ex.a_text+ex.a_data);
 355                         goto beyond_if;
 356                 }
 357
 358                 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 359                                 PROT_READ | PROT_EXEC,
 360                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 361                                 MAP_EXECUTABLE | MAP_32BIT,
 362                                 fd_offset);
 363
 364                 if (error != N_TXTADDR(ex))
 365                         return error;
 366
 367                 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 368                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 369                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 370                                 MAP_EXECUTABLE | MAP_32BIT,
 371                                 fd_offset + ex.a_text);
 372                 if (error != N_DATADDR(ex))
 373                         return error;
 374         }
 375 beyond_if:
 376         set_binfmt(&aout_format);
 377
 378         set_brk(current->mm->start_brk, current->mm->brk);
 379
 380         current->mm->start_stack =
 381                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 382         /* start thread */
 383         loadsegment(fs, 0);
 384         loadsegment(ds, __USER32_DS);
 385         loadsegment(es, __USER32_DS);
 386         load_gs_index(0);
 387         (regs)->ip = ex.a_entry;
 388         (regs)->sp = current->mm->start_stack;
 389         (regs)->flags = 0x200;
 390         (regs)->cs = __USER32_CS;
 391         (regs)->ss = __USER32_DS;
 392         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 393         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 394         set_fs(USER_DS);
 395         return 0;
 396 }
 397
 398 static int load_aout_library(struct file *file)
 399 {
 400         unsigned long bss, start_addr, len, error;
 401         int retval;
 402         struct exec ex;
 403
 404
 405         retval = -ENOEXEC;
 406         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 407         if (error != sizeof(ex))
 408                 goto out;
 409
 410         /* We come in here for the regular a.out style of shared libraries */
 411         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 412             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 413             i_size_read(file_inode(file)) <
 414             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 415                 goto out;
 416         }
 417
 418         if (N_FLAGS(ex))
 419                 goto out;
 420
 421         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 422            this off to get the starting address for the page */
 423
 424         start_addr =  ex.a_entry & 0xfffff000;
 425
 426         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 427 #ifdef WARN_OLD
 428                 static unsigned long error_time;
 429                 if (time_after(jiffies, error_time + 5*HZ)) {
 430                         printk(KERN_WARNING
 431                                "N_TXTOFF is not page aligned. Please convert "
 432                                "library: %pD\n",
 433                                file);
 434                         error_time = jiffies;
 435                 }
 436 #endif
 437                 vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 438
 439                 read_code(file, start_addr, N_TXTOFF(ex),
 440                           ex.a_text + ex.a_data);
 441                 retval = 0;
 442                 goto out;
 443         }
 444         /* Now use mmap to map the library into memory. */
 445         error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
 446                         PROT_READ | PROT_WRITE | PROT_EXEC,
 447                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 448                         N_TXTOFF(ex));
 449         retval = error;
 450         if (error != start_addr)
 451                 goto out;
 452
 453         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 454         bss = ex.a_text + ex.a_data + ex.a_bss;
 455         if (bss > len) {
 456                 error = vm_brk(start_addr + len, bss - len);
 457                 retval = error;
 458                 if (error != start_addr + len)
 459                         goto out;
 460         }
 461         retval = 0;
 462 out:
 463         return retval;
 464 }
 465
 466 static int __init init_aout_binfmt(void)
 467 {
 468         register_binfmt(&aout_format);
 469         return 0;
 470 }
 471
 472 static void __exit exit_aout_binfmt(void)
 473 {
 474         unregister_binfmt(&aout_format);
 475 }
 476
 477 module_init(init_aout_binfmt);
 478 module_exit(exit_aout_binfmt);
 479 MODULE_LICENSE("GPL");