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 fill_dump(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
 161         fill_dump(cprm->regs, &dump);
 162
 163         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 164         dump.u_ar0 = offsetof(struct user32, regs);
 165         dump.signal = cprm->siginfo->si_signo;
 166
 167         /*
 168          * If the size of the dump file exceeds the rlimit, then see
 169          * what would happen if we wrote the stack, but not the data
 170          * area.
 171          */
 172         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
 173                 dump.u_dsize = 0;
 174
 175         /* Make sure we have enough room to write the stack and data areas. */
 176         if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit)
 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 (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 182                        dump.u_dsize << PAGE_SHIFT))
 183                 dump.u_dsize = 0;
 184         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 185                        dump.u_ssize << PAGE_SHIFT))
 186                 dump.u_ssize = 0;
 187
 188         set_fs(KERNEL_DS);
 189         /* struct user */
 190         if (!dump_emit(cprm, &dump, sizeof(dump)))
 191                 goto end_coredump;
 192         /* Now dump all of the user data.  Include malloced stuff as well */
 193         if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
 194                 goto end_coredump;
 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                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 202                         goto end_coredump;
 203         }
 204         /* Now prepare to dump the stack area */
 205         if (dump.u_ssize != 0) {
 206                 dump_start = START_STACK(dump);
 207                 dump_size = dump.u_ssize << PAGE_SHIFT;
 208                 if (!dump_emit(cprm, (void *)dump_start, dump_size))
 209                         goto end_coredump;
 210         }
 211 end_coredump:
 212         set_fs(fs);
 213         return has_dumped;
 214 }
 215 #endif
 216
 217 /*
 218  * create_aout_tables() parses the env- and arg-strings in new user
 219  * memory and creates the pointer tables from them, and puts their
 220  * addresses on the "stack", returning the new stack pointer value.
 221  */
 222 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 223 {
 224         u32 __user *argv, *envp, *sp;
 225         int argc = bprm->argc, envc = bprm->envc;
 226
 227         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 228         sp -= envc+1;
 229         envp = sp;
 230         sp -= argc+1;
 231         argv = sp;
 232         put_user((unsigned long) envp, --sp);
 233         put_user((unsigned long) argv, --sp);
 234         put_user(argc, --sp);
 235         current->mm->arg_start = (unsigned long) p;
 236         while (argc-- > 0) {
 237                 char c;
 238
 239                 put_user((u32)(unsigned long)p, argv++);
 240                 do {
 241                         get_user(c, p++);
 242                 } while (c);
 243         }
 244         put_user(0, argv);
 245         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 246         while (envc-- > 0) {
 247                 char c;
 248
 249                 put_user((u32)(unsigned long)p, envp++);
 250                 do {
 251                         get_user(c, p++);
 252                 } while (c);
 253         }
 254         put_user(0, envp);
 255         current->mm->env_end = (unsigned long) p;
 256         return sp;
 257 }
 258
 259 /*
 260  * These are the functions used to load a.out style executables and shared
 261  * libraries.  There is no binary dependent code anywhere else.
 262  */
 263 static int load_aout_binary(struct linux_binprm *bprm)
 264 {
 265         unsigned long error, fd_offset, rlim;
 266         struct pt_regs *regs = current_pt_regs();
 267         struct exec ex;
 268         int retval;
 269
 270         ex = *((struct exec *) bprm->buf);              /* exec-header */
 271         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 272              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 273             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 274             i_size_read(file_inode(bprm->file)) <
 275             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 276                 return -ENOEXEC;
 277         }
 278
 279         fd_offset = N_TXTOFF(ex);
 280
 281         /* Check initial limits. This avoids letting people circumvent
 282          * size limits imposed on them by creating programs with large
 283          * arrays in the data or bss.
 284          */
 285         rlim = rlimit(RLIMIT_DATA);
 286         if (rlim >= RLIM_INFINITY)
 287                 rlim = ~0;
 288         if (ex.a_data + ex.a_bss > rlim)
 289                 return -ENOMEM;
 290
 291         /* Flush all traces of the currently running executable */
 292         retval = flush_old_exec(bprm);
 293         if (retval)
 294                 return retval;
 295
 296         /* OK, This is the point of no return */
 297         set_personality(PER_LINUX);
 298         set_personality_ia32(false);
 299
 300         setup_new_exec(bprm);
 301
 302         regs->cs = __USER32_CS;
 303         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 304                 regs->r13 = regs->r14 = regs->r15 = 0;
 305
 306         current->mm->end_code = ex.a_text +
 307                 (current->mm->start_code = N_TXTADDR(ex));
 308         current->mm->end_data = ex.a_data +
 309                 (current->mm->start_data = N_DATADDR(ex));
 310         current->mm->brk = ex.a_bss +
 311                 (current->mm->start_brk = N_BSSADDR(ex));
 312
 313         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 314         if (retval < 0)
 315                 return retval;
 316
 317         install_exec_creds(bprm);
 318
 319         if (N_MAGIC(ex) == OMAGIC) {
 320                 unsigned long text_addr, map_size;
 321
 322                 text_addr = N_TXTADDR(ex);
 323                 map_size = ex.a_text+ex.a_data;
 324
 325                 error = vm_brk(text_addr & PAGE_MASK, map_size);
 326
 327                 if (error)
 328                         return error;
 329
 330                 error = read_code(bprm->file, text_addr, 32,
 331                                   ex.a_text + ex.a_data);
 332                 if ((signed long)error < 0)
 333                         return error;
 334         } else {
 335 #ifdef WARN_OLD
 336                 static unsigned long error_time, error_time2;
 337                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 338                     (N_MAGIC(ex) != NMAGIC) &&
 339                                 time_after(jiffies, error_time2 + 5*HZ)) {
 340                         printk(KERN_NOTICE "executable not page aligned\n");
 341                         error_time2 = jiffies;
 342                 }
 343
 344                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 345                             time_after(jiffies, error_time + 5*HZ)) {
 346                         printk(KERN_WARNING
 347                                "fd_offset is not page aligned. Please convert "
 348                                "program: %pD\n",
 349                                bprm->file);
 350                         error_time = jiffies;
 351                 }
 352 #endif
 353
 354                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 355                         error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 356                         if (error)
 357                                 return error;
 358
 359                         read_code(bprm->file, N_TXTADDR(ex), fd_offset,
 360                                         ex.a_text+ex.a_data);
 361                         goto beyond_if;
 362                 }
 363
 364                 error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 365                                 PROT_READ | PROT_EXEC,
 366                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 367                                 MAP_EXECUTABLE | MAP_32BIT,
 368                                 fd_offset);
 369
 370                 if (error != N_TXTADDR(ex))
 371                         return error;
 372
 373                 error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 374                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 375                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 376                                 MAP_EXECUTABLE | MAP_32BIT,
 377                                 fd_offset + ex.a_text);
 378                 if (error != N_DATADDR(ex))
 379                         return error;
 380         }
 381
 382 beyond_if:
 383         error = set_brk(current->mm->start_brk, current->mm->brk);
 384         if (error)
 385                 return error;
 386
 387         set_binfmt(&aout_format);
 388
 389         current->mm->start_stack =
 390                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 391         /* start thread */
 392         loadsegment(fs, 0);
 393         loadsegment(ds, __USER32_DS);
 394         loadsegment(es, __USER32_DS);
 395         load_gs_index(0);
 396         (regs)->ip = ex.a_entry;
 397         (regs)->sp = current->mm->start_stack;
 398         (regs)->flags = 0x200;
 399         (regs)->cs = __USER32_CS;
 400         (regs)->ss = __USER32_DS;
 401         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 402         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 403         set_fs(USER_DS);
 404         return 0;
 405 }
 406
 407 static int load_aout_library(struct file *file)
 408 {
 409         unsigned long bss, start_addr, len, error;
 410         int retval;
 411         struct exec ex;
 412         loff_t pos = 0;
 413
 414         retval = -ENOEXEC;
 415         error = kernel_read(file, &ex, sizeof(ex), &pos);
 416         if (error != sizeof(ex))
 417                 goto out;
 418
 419         /* We come in here for the regular a.out style of shared libraries */
 420         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 421             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 422             i_size_read(file_inode(file)) <
 423             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 424                 goto out;
 425         }
 426
 427         if (N_FLAGS(ex))
 428                 goto out;
 429
 430         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 431            this off to get the starting address for the page */
 432
 433         start_addr =  ex.a_entry & 0xfffff000;
 434
 435         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 436 #ifdef WARN_OLD
 437                 static unsigned long error_time;
 438                 if (time_after(jiffies, error_time + 5*HZ)) {
 439                         printk(KERN_WARNING
 440                                "N_TXTOFF is not page aligned. Please convert "
 441                                "library: %pD\n",
 442                                file);
 443                         error_time = jiffies;
 444                 }
 445 #endif
 446                 retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 447                 if (retval)
 448                         goto out;
 449
 450                 read_code(file, start_addr, N_TXTOFF(ex),
 451                           ex.a_text + ex.a_data);
 452                 retval = 0;
 453                 goto out;
 454         }
 455         /* Now use mmap to map the library into memory. */
 456         error = vm_mmap(file, start_addr, ex.a_text + ex.a_data,
 457                         PROT_READ | PROT_WRITE | PROT_EXEC,
 458                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 459                         N_TXTOFF(ex));
 460         retval = error;
 461         if (error != start_addr)
 462                 goto out;
 463
 464         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 465         bss = ex.a_text + ex.a_data + ex.a_bss;
 466         if (bss > len) {
 467                 retval = vm_brk(start_addr + len, bss - len);
 468                 if (retval)
 469                         goto out;
 470         }
 471         retval = 0;
 472 out:
 473         return retval;
 474 }
 475
 476 static int __init init_aout_binfmt(void)
 477 {
 478         register_binfmt(&aout_format);
 479         return 0;
 480 }
 481
 482 static void __exit exit_aout_binfmt(void)
 483 {
 484         unregister_binfmt(&aout_format);
 485 }
 486
 487 module_init(init_aout_binfmt);
 488 module_exit(exit_aout_binfmt);
 489 MODULE_LICENSE("GPL");