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 fill_dump(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
 160         fill_dump(cprm->regs, &dump);
 161
 162         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 163         dump.u_ar0 = offsetof(struct user32, regs);
 164         dump.signal = cprm->siginfo->si_signo;
 165
 166         /*
 167          * If the size of the dump file exceeds the rlimit, then see
 168          * what would happen if we wrote the stack, but not the data
 169          * area.
 170          */
 171         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->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 > cprm->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),
 181                        dump.u_dsize << PAGE_SHIFT))
 182                 dump.u_dsize = 0;
 183         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 184                        dump.u_ssize << PAGE_SHIFT))
 185                 dump.u_ssize = 0;
 186
 187         set_fs(KERNEL_DS);
 188         /* struct user */
 189         if (!dump_emit(cprm, &dump, sizeof(dump)))
 190                 goto end_coredump;
 191         /* Now dump all of the user data.  Include malloced stuff as well */
 192         if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
 193                 goto end_coredump;
 194         /* now we start writing out the user space info */
 195         set_fs(USER_DS);
 196         /* Dump the data area */
 197         if (dump.u_dsize != 0) {
 198                 dump_start = START_DATA(dump);
 199                 dump_size = dump.u_dsize << PAGE_SHIFT;
 200                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 201                         goto end_coredump;
 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                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 208                         goto end_coredump;
 209         }
 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, *envp, *sp;
 224         int argc = bprm->argc, 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
 238                 put_user((u32)(unsigned long)p, argv++);
 239                 do {
 240                         get_user(c, p++);
 241                 } while (c);
 242         }
 243         put_user(0, argv);
 244         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 245         while (envc-- > 0) {
 246                 char c;
 247
 248                 put_user((u32)(unsigned long)p, envp++);
 249                 do {
 250                         get_user(c, p++);
 251                 } while (c);
 252         }
 253         put_user(0, envp);
 254         current->mm->env_end = (unsigned long) p;
 255         return sp;
 256 }
 257
 258 /*
 259  * These are the functions used to load a.out style executables and shared
 260  * libraries.  There is no binary dependent code anywhere else.
 261  */
 262 static int load_aout_binary(struct linux_binprm *bprm)
 263 {
 264         unsigned long error, fd_offset, rlim;
 265         struct pt_regs *regs = current_pt_regs();
 266         struct exec ex;
 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(file_inode(bprm->file)) <
 274             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 275                 return -ENOEXEC;
 276         }
 277
 278         fd_offset = N_TXTOFF(ex);
 279
 280         /* Check initial limits. This avoids letting people circumvent
 281          * size limits imposed on them by creating programs with large
 282          * arrays in the data or bss.
 283          */
 284         rlim = rlimit(RLIMIT_DATA);
 285         if (rlim >= RLIM_INFINITY)
 286                 rlim = ~0;
 287         if (ex.a_data + ex.a_bss > rlim)
 288                 return -ENOMEM;
 289
 290         /* Flush all traces of the currently running executable */
 291         retval = flush_old_exec(bprm);
 292         if (retval)
 293                 return retval;
 294
 295         /* OK, This is the point of no return */
 296         set_personality(PER_LINUX);
 297         set_personality_ia32(false);
 298
 299         setup_new_exec(bprm);
 300
 301         regs->cs = __USER32_CS;
 302         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 303                 regs->r13 = regs->r14 = regs->r15 = 0;
 304
 305         current->mm->end_code = ex.a_text +
 306                 (current->mm->start_code = N_TXTADDR(ex));
 307         current->mm->end_data = ex.a_data +
 308                 (current->mm->start_data = N_DATADDR(ex));
 309         current->mm->brk = ex.a_bss +
 310                 (current->mm->start_brk = N_BSSADDR(ex));
 311
 312         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 313         if (retval < 0)
 314                 return retval;
 315
 316         install_exec_creds(bprm);
 317
 318         if (N_MAGIC(ex) == OMAGIC) {
 319                 unsigned long text_addr, map_size;
 320
 321                 text_addr = N_TXTADDR(ex);
 322                 map_size = ex.a_text+ex.a_data;
 323
 324                 error = vm_brk(text_addr & PAGE_MASK, map_size);
 325
 326                 if (error != (text_addr & PAGE_MASK))
 327                         return error;
 328
 329                 error = read_code(bprm->file, text_addr, 32,
 330                                   ex.a_text + ex.a_data);
 331                 if ((signed long)error < 0)
 332                         return error;
 333         } else {
 334 #ifdef WARN_OLD
 335                 static unsigned long error_time, error_time2;
 336                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 337                     (N_MAGIC(ex) != NMAGIC) &&
 338                                 time_after(jiffies, error_time2 + 5*HZ)) {
 339                         printk(KERN_NOTICE "executable not page aligned\n");
 340                         error_time2 = jiffies;
 341                 }
 342
 343                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 344                             time_after(jiffies, error_time + 5*HZ)) {
 345                         printk(KERN_WARNING
 346                                "fd_offset is not page aligned. Please convert "
 347                                "program: %pD\n",
 348                                bprm->file);
 349                         error_time = jiffies;
 350                 }
 351 #endif
 352
 353                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 354                         vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 355                         read_code(bprm->file, N_TXTADDR(ex), fd_offset,
 356                                         ex.a_text+ex.a_data);
 357                         goto beyond_if;
 358                 }
 359
 360                 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 361                                 PROT_READ | PROT_EXEC,
 362                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 363                                 MAP_EXECUTABLE | MAP_32BIT,
 364                                 fd_offset);
 365
 366                 if (error != N_TXTADDR(ex))
 367                         return error;
 368
 369                 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 370                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 371                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 372                                 MAP_EXECUTABLE | MAP_32BIT,
 373                                 fd_offset + ex.a_text);
 374                 if (error != N_DATADDR(ex))
 375                         return error;
 376         }
 377 beyond_if:
 378         set_binfmt(&aout_format);
 379
 380         set_brk(current->mm->start_brk, current->mm->brk);
 381
 382         current->mm->start_stack =
 383                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 384         /* start thread */
 385         loadsegment(fs, 0);
 386         loadsegment(ds, __USER32_DS);
 387         loadsegment(es, __USER32_DS);
 388         load_gs_index(0);
 389         (regs)->ip = ex.a_entry;
 390         (regs)->sp = current->mm->start_stack;
 391         (regs)->flags = 0x200;
 392         (regs)->cs = __USER32_CS;
 393         (regs)->ss = __USER32_DS;
 394         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 395         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 396         set_fs(USER_DS);
 397         return 0;
 398 }
 399
 400 static int load_aout_library(struct file *file)
 401 {
 402         unsigned long bss, start_addr, len, error;
 403         int retval;
 404         struct exec ex;
 405
 406
 407         retval = -ENOEXEC;
 408         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 409         if (error != sizeof(ex))
 410                 goto out;
 411
 412         /* We come in here for the regular a.out style of shared libraries */
 413         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 414             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 415             i_size_read(file_inode(file)) <
 416             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 417                 goto out;
 418         }
 419
 420         if (N_FLAGS(ex))
 421                 goto out;
 422
 423         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 424            this off to get the starting address for the page */
 425
 426         start_addr =  ex.a_entry & 0xfffff000;
 427
 428         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 429 #ifdef WARN_OLD
 430                 static unsigned long error_time;
 431                 if (time_after(jiffies, error_time + 5*HZ)) {
 432                         printk(KERN_WARNING
 433                                "N_TXTOFF is not page aligned. Please convert "
 434                                "library: %pD\n",
 435                                file);
 436                         error_time = jiffies;
 437                 }
 438 #endif
 439                 vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 440
 441                 read_code(file, start_addr, N_TXTOFF(ex),
 442                           ex.a_text + ex.a_data);
 443                 retval = 0;
 444                 goto out;
 445         }
 446         /* Now use mmap to map the library into memory. */
 447         error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
 448                         PROT_READ | PROT_WRITE | PROT_EXEC,
 449                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 450                         N_TXTOFF(ex));
 451         retval = error;
 452         if (error != start_addr)
 453                 goto out;
 454
 455         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 456         bss = ex.a_text + ex.a_data + ex.a_bss;
 457         if (bss > len) {
 458                 error = vm_brk(start_addr + len, bss - len);
 459                 retval = error;
 460                 if (error != start_addr + len)
 461                         goto out;
 462         }
 463         retval = 0;
 464 out:
 465         return retval;
 466 }
 467
 468 static int __init init_aout_binfmt(void)
 469 {
 470         register_binfmt(&aout_format);
 471         return 0;
 472 }
 473
 474 static void __exit exit_aout_binfmt(void)
 475 {
 476         unregister_binfmt(&aout_format);
 477 }
 478
 479 module_init(init_aout_binfmt);
 480 module_exit(exit_aout_binfmt);
 481 MODULE_LICENSE("GPL");