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 #include <linux/sched/task_stack.h>
  30
  31 #include <linux/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
  39 static int load_aout_binary(struct linux_binprm *);
  40 static int load_aout_library(struct file *);
  41
  42 #ifdef CONFIG_COREDUMP
  43 static int aout_core_dump(struct coredump_params *);
  44
  45 static unsigned long get_dr(int n)
  46 {
  47         struct perf_event *bp = current->thread.ptrace_bps[n];
  48         return bp ? bp->hw.info.address : 0;
  49 }
  50
  51 /*
  52  * fill in the user structure for a core dump..
  53  */
  54 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  55 {
  56         u32 fs, gs;
  57         memset(dump, 0, sizeof(*dump));
  58
  59 /* changed the size calculations - should hopefully work better. lbt */
  60         dump->magic = CMAGIC;
  61         dump->start_code = 0;
  62         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  63         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  64         dump->u_dsize = ((unsigned long)
  65                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  66         dump->u_dsize -= dump->u_tsize;
  67         dump->u_debugreg[0] = get_dr(0);
  68         dump->u_debugreg[1] = get_dr(1);
  69         dump->u_debugreg[2] = get_dr(2);
  70         dump->u_debugreg[3] = get_dr(3);
  71         dump->u_debugreg[6] = current->thread.debugreg6;
  72         dump->u_debugreg[7] = current->thread.ptrace_dr7;
  73
  74         if (dump->start_stack < 0xc0000000) {
  75                 unsigned long tmp;
  76
  77                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  78                 dump->u_ssize = tmp >> PAGE_SHIFT;
  79         }
  80
  81         dump->regs.ebx = regs->bx;
  82         dump->regs.ecx = regs->cx;
  83         dump->regs.edx = regs->dx;
  84         dump->regs.esi = regs->si;
  85         dump->regs.edi = regs->di;
  86         dump->regs.ebp = regs->bp;
  87         dump->regs.eax = regs->ax;
  88         dump->regs.ds = current->thread.ds;
  89         dump->regs.es = current->thread.es;
  90         savesegment(fs, fs);
  91         dump->regs.fs = fs;
  92         savesegment(gs, gs);
  93         dump->regs.gs = gs;
  94         dump->regs.orig_eax = regs->orig_ax;
  95         dump->regs.eip = regs->ip;
  96         dump->regs.cs = regs->cs;
  97         dump->regs.eflags = regs->flags;
  98         dump->regs.esp = regs->sp;
  99         dump->regs.ss = regs->ss;
 100
 101 #if 1 /* FIXME */
 102         dump->u_fpvalid = 0;
 103 #else
 104         dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 105 #endif
 106 }
 107
 108 #endif
 109
 110 static struct linux_binfmt aout_format = {
 111         .module         = THIS_MODULE,
 112         .load_binary    = load_aout_binary,
 113         .load_shlib     = load_aout_library,
 114 #ifdef CONFIG_COREDUMP
 115         .core_dump      = aout_core_dump,
 116 #endif
 117         .min_coredump   = PAGE_SIZE
 118 };
 119
 120 static int set_brk(unsigned long start, unsigned long end)
 121 {
 122         start = PAGE_ALIGN(start);
 123         end = PAGE_ALIGN(end);
 124         if (end <= start)
 125                 return 0;
 126         return vm_brk(start, end - start);
 127 }
 128
 129 #ifdef CONFIG_COREDUMP
 130 /*
 131  * These are the only things you should do on a core-file: use only these
 132  * macros to write out all the necessary info.
 133  */
 134
 135 #include <linux/coredump.h>
 136
 137 #define START_DATA(u)   (u.u_tsize << PAGE_SHIFT)
 138 #define START_STACK(u)  (u.start_stack)
 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(struct coredump_params *cprm)
 151 {
 152         mm_segment_t fs;
 153         int has_dumped = 0;
 154         unsigned long dump_start, dump_size;
 155         struct user32 dump;
 156
 157         fs = get_fs();
 158         set_fs(KERNEL_DS);
 159         has_dumped = 1;
 160         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 161         dump.u_ar0 = offsetof(struct user32, regs);
 162         dump.signal = cprm->siginfo->si_signo;
 163         dump_thread32(cprm->regs, &dump);
 164
 165         /*
 166          * If the size of the dump file exceeds the rlimit, then see
 167          * what would happen if we wrote the stack, but not the data
 168          * area.
 169          */
 170         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
 171                 dump.u_dsize = 0;
 172
 173         /* Make sure we have enough room to write the stack and data areas. */
 174         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
 175                 dump.u_ssize = 0;
 176
 177         /* make sure we actually have a data and stack area to dump */
 178         set_fs(USER_DS);
 179         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 180                        dump.u_dsize << PAGE_SHIFT))
 181                 dump.u_dsize = 0;
 182         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 183                        dump.u_ssize << PAGE_SHIFT))
 184                 dump.u_ssize = 0;
 185
 186         set_fs(KERNEL_DS);
 187         /* struct user */
 188         if (!dump_emit(cprm, &dump, sizeof(dump)))
 189                 goto end_coredump;
 190         /* Now dump all of the user data.  Include malloced stuff as well */
 191         if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
 192                 goto end_coredump;
 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                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 200                         goto end_coredump;
 201         }
 202         /* Now prepare to dump the stack area */
 203         if (dump.u_ssize != 0) {
 204                 dump_start = START_STACK(dump);
 205                 dump_size = dump.u_ssize << PAGE_SHIFT;
 206                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 207                         goto end_coredump;
 208         }
 209 end_coredump:
 210         set_fs(fs);
 211         return has_dumped;
 212 }
 213 #endif
 214
 215 /*
 216  * create_aout_tables() parses the env- and arg-strings in new user
 217  * memory and creates the pointer tables from them, and puts their
 218  * addresses on the "stack", returning the new stack pointer value.
 219  */
 220 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 221 {
 222         u32 __user *argv, *envp, *sp;
 223         int argc = bprm->argc, envc = bprm->envc;
 224
 225         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 226         sp -= envc+1;
 227         envp = sp;
 228         sp -= argc+1;
 229         argv = sp;
 230         put_user((unsigned long) envp, --sp);
 231         put_user((unsigned long) argv, --sp);
 232         put_user(argc, --sp);
 233         current->mm->arg_start = (unsigned long) p;
 234         while (argc-- > 0) {
 235                 char c;
 236
 237                 put_user((u32)(unsigned long)p, argv++);
 238                 do {
 239                         get_user(c, p++);
 240                 } while (c);
 241         }
 242         put_user(0, argv);
 243         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 244         while (envc-- > 0) {
 245                 char c;
 246
 247                 put_user((u32)(unsigned long)p, envp++);
 248                 do {
 249                         get_user(c, p++);
 250                 } while (c);
 251         }
 252         put_user(0, envp);
 253         current->mm->env_end = (unsigned long) p;
 254         return sp;
 255 }
 256
 257 /*
 258  * These are the functions used to load a.out style executables and shared
 259  * libraries.  There is no binary dependent code anywhere else.
 260  */
 261 static int load_aout_binary(struct linux_binprm *bprm)
 262 {
 263         unsigned long error, fd_offset, rlim;
 264         struct pt_regs *regs = current_pt_regs();
 265         struct exec ex;
 266         int retval;
 267
 268         ex = *((struct exec *) bprm->buf);              /* exec-header */
 269         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 270              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 271             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 272             i_size_read(file_inode(bprm->file)) <
 273             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 = rlimit(RLIMIT_DATA);
 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         /* OK, This is the point of no return */
 295         set_personality(PER_LINUX);
 296         set_personality_ia32(false);
 297
 298         setup_new_exec(bprm);
 299
 300         regs->cs = __USER32_CS;
 301         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 302                 regs->r13 = regs->r14 = regs->r15 = 0;
 303
 304         current->mm->end_code = ex.a_text +
 305                 (current->mm->start_code = N_TXTADDR(ex));
 306         current->mm->end_data = ex.a_data +
 307                 (current->mm->start_data = N_DATADDR(ex));
 308         current->mm->brk = ex.a_bss +
 309                 (current->mm->start_brk = N_BSSADDR(ex));
 310
 311         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 312         if (retval < 0)
 313                 return retval;
 314
 315         install_exec_creds(bprm);
 316
 317         if (N_MAGIC(ex) == OMAGIC) {
 318                 unsigned long text_addr, map_size;
 319
 320                 text_addr = N_TXTADDR(ex);
 321                 map_size = ex.a_text+ex.a_data;
 322
 323                 error = vm_brk(text_addr & PAGE_MASK, map_size);
 324
 325                 if (error)
 326                         return error;
 327
 328                 error = read_code(bprm->file, text_addr, 32,
 329                                   ex.a_text + ex.a_data);
 330                 if ((signed long)error < 0)
 331                         return error;
 332         } else {
 333 #ifdef WARN_OLD
 334                 static unsigned long error_time, error_time2;
 335                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 336                     (N_MAGIC(ex) != NMAGIC) &&
 337                                 time_after(jiffies, error_time2 + 5*HZ)) {
 338                         printk(KERN_NOTICE "executable not page aligned\n");
 339                         error_time2 = jiffies;
 340                 }
 341
 342                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 343                             time_after(jiffies, error_time + 5*HZ)) {
 344                         printk(KERN_WARNING
 345                                "fd_offset is not page aligned. Please convert "
 346                                "program: %pD\n",
 347                                bprm->file);
 348                         error_time = jiffies;
 349                 }
 350 #endif
 351
 352                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 353                         error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 354                         if (error)
 355                                 return error;
 356
 357                         read_code(bprm->file, N_TXTADDR(ex), fd_offset,
 358                                         ex.a_text+ex.a_data);
 359                         goto beyond_if;
 360                 }
 361
 362                 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 363                                 PROT_READ | PROT_EXEC,
 364                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 365                                 MAP_EXECUTABLE | MAP_32BIT,
 366                                 fd_offset);
 367
 368                 if (error != N_TXTADDR(ex))
 369                         return error;
 370
 371                 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 372                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 373                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 374                                 MAP_EXECUTABLE | MAP_32BIT,
 375                                 fd_offset + ex.a_text);
 376                 if (error != N_DATADDR(ex))
 377                         return error;
 378         }
 379
 380 beyond_if:
 381         error = set_brk(current->mm->start_brk, current->mm->brk);
 382         if (error)
 383                 return error;
 384
 385         set_binfmt(&aout_format);
 386
 387         current->mm->start_stack =
 388                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 389         /* start thread */
 390         loadsegment(fs, 0);
 391         loadsegment(ds, __USER32_DS);
 392         loadsegment(es, __USER32_DS);
 393         load_gs_index(0);
 394         (regs)->ip = ex.a_entry;
 395         (regs)->sp = current->mm->start_stack;
 396         (regs)->flags = 0x200;
 397         (regs)->cs = __USER32_CS;
 398         (regs)->ss = __USER32_DS;
 399         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 400         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 401         set_fs(USER_DS);
 402         return 0;
 403 }
 404
 405 static int load_aout_library(struct file *file)
 406 {
 407         unsigned long bss, start_addr, len, error;
 408         int retval;
 409         struct exec ex;
 410         loff_t pos = 0;
 411
 412         retval = -ENOEXEC;
 413         error = kernel_read(file, &ex, sizeof(ex), &pos);
 414         if (error != sizeof(ex))
 415                 goto out;
 416
 417         /* We come in here for the regular a.out style of shared libraries */
 418         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 419             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 420             i_size_read(file_inode(file)) <
 421             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 422                 goto out;
 423         }
 424
 425         if (N_FLAGS(ex))
 426                 goto out;
 427
 428         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 429            this off to get the starting address for the page */
 430
 431         start_addr =  ex.a_entry & 0xfffff000;
 432
 433         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 434 #ifdef WARN_OLD
 435                 static unsigned long error_time;
 436                 if (time_after(jiffies, error_time + 5*HZ)) {
 437                         printk(KERN_WARNING
 438                                "N_TXTOFF is not page aligned. Please convert "
 439                                "library: %pD\n",
 440                                file);
 441                         error_time = jiffies;
 442                 }
 443 #endif
 444                 retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 445                 if (retval)
 446                         goto out;
 447
 448                 read_code(file, start_addr, N_TXTOFF(ex),
 449                           ex.a_text + ex.a_data);
 450                 retval = 0;
 451                 goto out;
 452         }
 453         /* Now use mmap to map the library into memory. */
 454         error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
 455                         PROT_READ | PROT_WRITE | PROT_EXEC,
 456                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 457                         N_TXTOFF(ex));
 458         retval = error;
 459         if (error != start_addr)
 460                 goto out;
 461
 462         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 463         bss = ex.a_text + ex.a_data + ex.a_bss;
 464         if (bss > len) {
 465                 retval = vm_brk(start_addr + len, bss - len);
 466                 if (retval)
 467                         goto out;
 468         }
 469         retval = 0;
 470 out:
 471         return retval;
 472 }
 473
 474 static int __init init_aout_binfmt(void)
 475 {
 476         register_binfmt(&aout_format);
 477         return 0;
 478 }
 479
 480 static void __exit exit_aout_binfmt(void)
 481 {
 482         unregister_binfmt(&aout_format);
 483 }
 484
 485 module_init(init_aout_binfmt);
 486 module_exit(exit_aout_binfmt);
 487 MODULE_LICENSE("GPL");