fs/binfmt_aout.c

   1 /*
   2  *  linux/fs/binfmt_aout.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
   5  */
   6
   7 #include <linux/module.h>
   8
   9 #include <linux/sched.h>
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/mman.h>
  13 #include <linux/a.out.h>
  14 #include <linux/errno.h>
  15 #include <linux/signal.h>
  16 #include <linux/string.h>
  17 #include <linux/fs.h>
  18 #include <linux/file.h>
  19 #include <linux/stat.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/user.h>
  23 #include <linux/malloc.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/personality.h>
  26 #include <linux/init.h>
  27
  28 #include <asm/system.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgalloc.h>
  31
  32 static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  33 static int load_aout_library(struct file*);
  34 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);
  35
  36 extern void dump_thread(struct pt_regs *, struct user *);
  37
  38 static struct linux_binfmt aout_format = {
  39         NULL, THIS_MODULE, load_aout_binary, load_aout_library, aout_core_dump, PAGE_SIZE
  40 };
  41
  42 static void set_brk(unsigned long start, unsigned long end)
  43 {
  44         start = PAGE_ALIGN(start);
  45         end = PAGE_ALIGN(end);
  46         if (end <= start)
  47                 return;
  48         do_brk(start, end - start);
  49 }
  50
  51 /*
  52  * These are the only things you should do on a core-file: use only these
  53  * macros to write out all the necessary info.
  54  */
  55
  56 static int dump_write(struct file *file, const void *addr, int nr)
  57 {
  58         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  59 }
  60
  61 #define DUMP_WRITE(addr, nr)    \
  62         if (!dump_write(file, (void *)(addr), (nr))) \
  63                 goto end_coredump;
  64
  65 #define DUMP_SEEK(offset) \
  66 if (file->f_op->llseek) { \
  67         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  68                 goto end_coredump; \
  69 } else file->f_pos = (offset)
  70
  71 /*
  72  * Routine writes a core dump image in the current directory.
  73  * Currently only a stub-function.
  74  *
  75  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  76  * changed due to the set[u|g]id. It's enforced by the "current->dumpable"
  77  * field, which also makes sure the core-dumps won't be recursive if the
  78  * dumping of the process results in another error..
  79  */
  80
  81 static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
  82 {
  83         mm_segment_t fs;
  84         int has_dumped = 0;
  85         unsigned long dump_start, dump_size;
  86         struct user dump;
  87 #if defined(__alpha__)
  88 #       define START_DATA(u)    (u.start_data)
  89 #elif defined(__sparc__)
  90 #       define START_DATA(u)    (u.u_tsize)
  91 #elif defined(__i386__) || defined(__mc68000__)
  92 #       define START_DATA(u)    (u.u_tsize << PAGE_SHIFT)
  93 #endif
  94 #ifdef __sparc__
  95 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
  96 #else
  97 #       define START_STACK(u)   (u.start_stack)
  98 #endif
  99
 100         fs = get_fs();
 101         set_fs(KERNEL_DS);
 102         has_dumped = 1;
 103         current->flags |= PF_DUMPCORE;
 104         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 105 #ifndef __sparc__
 106         dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
 107 #endif
 108         dump.signal = signr;
 109         dump_thread(regs, &dump);
 110
 111 /* If the size of the dump file exceeds the rlimit, then see what would happen
 112    if we wrote the stack, but not the data area.  */
 113 #ifdef __sparc__
 114         if ((dump.u_dsize+dump.u_ssize) >
 115             current->rlim[RLIMIT_CORE].rlim_cur)
 116                 dump.u_dsize = 0;
 117 #else
 118         if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
 119             current->rlim[RLIMIT_CORE].rlim_cur)
 120                 dump.u_dsize = 0;
 121 #endif
 122
 123 /* Make sure we have enough room to write the stack and data areas. */
 124 #ifdef __sparc__
 125         if ((dump.u_ssize) >
 126             current->rlim[RLIMIT_CORE].rlim_cur)
 127                 dump.u_ssize = 0;
 128 #else
 129         if ((dump.u_ssize+1) * PAGE_SIZE >
 130             current->rlim[RLIMIT_CORE].rlim_cur)
 131                 dump.u_ssize = 0;
 132 #endif
 133
 134 /* make sure we actually have a data and stack area to dump */
 135         set_fs(USER_DS);
 136 #ifdef __sparc__
 137         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize))
 138                 dump.u_dsize = 0;
 139         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize))
 140                 dump.u_ssize = 0;
 141 #else
 142         if (verify_area(VERIFY_READ, (void *) START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
 143                 dump.u_dsize = 0;
 144         if (verify_area(VERIFY_READ, (void *) START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
 145                 dump.u_ssize = 0;
 146 #endif
 147
 148         set_fs(KERNEL_DS);
 149 /* struct user */
 150         DUMP_WRITE(&dump,sizeof(dump));
 151 /* Now dump all of the user data.  Include malloced stuff as well */
 152 #ifndef __sparc__
 153         DUMP_SEEK(PAGE_SIZE);
 154 #endif
 155 /* now we start writing out the user space info */
 156         set_fs(USER_DS);
 157 /* Dump the data area */
 158         if (dump.u_dsize != 0) {
 159                 dump_start = START_DATA(dump);
 160 #ifdef __sparc__
 161                 dump_size = dump.u_dsize;
 162 #else
 163                 dump_size = dump.u_dsize << PAGE_SHIFT;
 164 #endif
 165                 DUMP_WRITE(dump_start,dump_size);
 166         }
 167 /* Now prepare to dump the stack area */
 168         if (dump.u_ssize != 0) {
 169                 dump_start = START_STACK(dump);
 170 #ifdef __sparc__
 171                 dump_size = dump.u_ssize;
 172 #else
 173                 dump_size = dump.u_ssize << PAGE_SHIFT;
 174 #endif
 175                 DUMP_WRITE(dump_start,dump_size);
 176         }
 177 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 178         set_fs(KERNEL_DS);
 179         DUMP_WRITE(current,sizeof(*current));
 180 end_coredump:
 181         set_fs(fs);
 182         return has_dumped;
 183 }
 184
 185 /*
 186  * create_aout_tables() parses the env- and arg-strings in new user
 187  * memory and creates the pointer tables from them, and puts their
 188  * addresses on the "stack", returning the new stack pointer value.
 189  */
 190 static unsigned long * create_aout_tables(char * p, struct linux_binprm * bprm)
 191 {
 192         char **argv, **envp;
 193         unsigned long * sp;
 194         int argc = bprm->argc;
 195         int envc = bprm->envc;
 196
 197         sp = (unsigned long *) ((-(unsigned long)sizeof(char *)) & (unsigned long) p);
 198 #ifdef __sparc__
 199         /* This imposes the proper stack alignment for a new process. */
 200         sp = (unsigned long *) (((unsigned long) sp) & ~7);
 201         if ((envc+argc+3)&1) --sp;
 202 #endif
 203 #ifdef __alpha__
 204 /* whee.. test-programs are so much fun. */
 205         put_user(0, --sp);
 206         put_user(0, --sp);
 207         if (bprm->loader) {
 208                 put_user(0, --sp);
 209                 put_user(0x3eb, --sp);
 210                 put_user(bprm->loader, --sp);
 211                 put_user(0x3ea, --sp);
 212         }
 213         put_user(bprm->exec, --sp);
 214         put_user(0x3e9, --sp);
 215 #endif
 216         sp -= envc+1;
 217         envp = (char **) sp;
 218         sp -= argc+1;
 219         argv = (char **) sp;
 220 #if defined(__i386__) || defined(__mc68000__)
 221         put_user((unsigned long) envp,--sp);
 222         put_user((unsigned long) argv,--sp);
 223 #endif
 224         put_user(argc,--sp);
 225         current->mm->arg_start = (unsigned long) p;
 226         while (argc-->0) {
 227                 char c;
 228                 put_user(p,argv++);
 229                 do {
 230                         get_user(c,p++);
 231                 } while (c);
 232         }
 233         put_user(NULL,argv);
 234         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 235         while (envc-->0) {
 236                 char c;
 237                 put_user(p,envp++);
 238                 do {
 239                         get_user(c,p++);
 240                 } while (c);
 241         }
 242         put_user(NULL,envp);
 243         current->mm->env_end = (unsigned long) p;
 244         return sp;
 245 }
 246
 247 /*
 248  * These are the functions used to load a.out style executables and shared
 249  * libraries.  There is no binary dependent code anywhere else.
 250  */
 251
 252 static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 253 {
 254         struct exec ex;
 255         unsigned long error;
 256         unsigned long fd_offset;
 257         unsigned long rlim;
 258         int retval;
 259
 260         ex = *((struct exec *) bprm->buf);              /* exec-header */
 261         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 262              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 263             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 264             bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 265                 return -ENOEXEC;
 266         }
 267
 268         fd_offset = N_TXTOFF(ex);
 269
 270         /* Check initial limits. This avoids letting people circumvent
 271          * size limits imposed on them by creating programs with large
 272          * arrays in the data or bss.
 273          */
 274         rlim = current->rlim[RLIMIT_DATA].rlim_cur;
 275         if (rlim >= RLIM_INFINITY)
 276                 rlim = ~0;
 277         if (ex.a_data + ex.a_bss > rlim)
 278                 return -ENOMEM;
 279
 280         /* Flush all traces of the currently running executable */
 281         retval = flush_old_exec(bprm);
 282         if (retval)
 283                 return retval;
 284
 285         /* OK, This is the point of no return */
 286 #if !defined(__sparc__)
 287         set_personality(PER_LINUX);
 288 #else
 289         set_personality(PER_SUNOS);
 290 #if !defined(__sparc_v9__)
 291         memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
 292 #endif
 293 #endif
 294
 295         current->mm->end_code = ex.a_text +
 296                 (current->mm->start_code = N_TXTADDR(ex));
 297         current->mm->end_data = ex.a_data +
 298                 (current->mm->start_data = N_DATADDR(ex));
 299         current->mm->brk = ex.a_bss +
 300                 (current->mm->start_brk = N_BSSADDR(ex));
 301
 302         current->mm->rss = 0;
 303         current->mm->mmap = NULL;
 304         compute_creds(bprm);
 305         current->flags &= ~PF_FORKNOEXEC;
 306 #ifdef __sparc__
 307         if (N_MAGIC(ex) == NMAGIC) {
 308                 loff_t pos = fd_offset;
 309                 /* Fuck me plenty... */
 310                 /* <AOL></AOL> */
 311                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 312                 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
 313                           ex.a_text, &pos);
 314                 error = do_brk(N_DATADDR(ex), ex.a_data);
 315                 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
 316                           ex.a_data, &pos);
 317                 goto beyond_if;
 318         }
 319 #endif
 320
 321         if (N_MAGIC(ex) == OMAGIC) {
 322                 loff_t pos;
 323 #if defined(__alpha__) || defined(__sparc__)
 324                 pos = fd_offset;
 325                 do_brk(N_TXTADDR(ex) & PAGE_MASK,
 326                         ex.a_text+ex.a_data + PAGE_SIZE - 1);
 327                 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
 328                           ex.a_text+ex.a_data, &pos);
 329 #else
 330                 pos = 32;
 331                 do_brk(0, ex.a_text+ex.a_data);
 332                 bprm->file->f_op->read(bprm->file, (char *) 0,
 333                         ex.a_text+ex.a_data, &pos);
 334 #endif
 335                 flush_icache_range((unsigned long) 0,
 336                                    (unsigned long) ex.a_text+ex.a_data);
 337         } else {
 338                 static unsigned long error_time, error_time2;
 339                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 340                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
 341                 {
 342                         printk(KERN_NOTICE "executable not page aligned\n");
 343                         error_time2 = jiffies;
 344                 }
 345
 346                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 347                     (jiffies-error_time) > 5*HZ)
 348                 {
 349                         printk(KERN_WARNING
 350                                "fd_offset is not page aligned. Please convert program: %s\n",
 351                                bprm->file->f_dentry->d_name.name);
 352                         error_time = jiffies;
 353                 }
 354
 355                 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
 356                         loff_t pos = fd_offset;
 357                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 358                         bprm->file->f_op->read(bprm->file,(char *)N_TXTADDR(ex),
 359                                         ex.a_text+ex.a_data, &pos);
 360                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 361                                            (unsigned long) N_TXTADDR(ex) +
 362                                            ex.a_text+ex.a_data);
 363                         goto beyond_if;
 364                 }
 365
 366                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 367                         PROT_READ | PROT_EXEC,
 368                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 369                         fd_offset);
 370
 371                 if (error != N_TXTADDR(ex)) {
 372                         send_sig(SIGKILL, current, 0);
 373                         return error;
 374                 }
 375
 376                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 377                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 378                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 379                                 fd_offset + ex.a_text);
 380                 if (error != N_DATADDR(ex)) {
 381                         send_sig(SIGKILL, current, 0);
 382                         return error;
 383                 }
 384         }
 385 beyond_if:
 386         set_binfmt(&aout_format);
 387
 388         set_brk(current->mm->start_brk, current->mm->brk);
 389
 390         retval = setup_arg_pages(bprm);
 391         if (retval < 0) {
 392                 /* Someone check-me: is this error path enough? */
 393                 send_sig(SIGKILL, current, 0);
 394                 return retval;
 395         }
 396
 397         current->mm->start_stack =
 398                 (unsigned long) create_aout_tables((char *) bprm->p, bprm);
 399 #ifdef __alpha__
 400         regs->gp = ex.a_gpvalue;
 401 #endif
 402         start_thread(regs, ex.a_entry, current->mm->start_stack);
 403         if (current->flags & PF_PTRACED)
 404                 send_sig(SIGTRAP, current, 0);
 405         return 0;
 406 }
 407
 408 static int load_aout_library(struct file *file)
 409 {
 410         struct inode * inode;
 411         unsigned long bss, start_addr, len;
 412         unsigned long error;
 413         int retval;
 414         struct exec ex;
 415
 416         inode = file->f_dentry->d_inode;
 417
 418         retval = -ENOEXEC;
 419         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 420         if (error != sizeof(ex))
 421                 goto out;
 422
 423         /* We come in here for the regular a.out style of shared libraries */
 424         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 425             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 426             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 427                 goto out;
 428         }
 429
 430         if (N_FLAGS(ex))
 431                 goto out;
 432
 433         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 434            this off to get the starting address for the page */
 435
 436         start_addr =  ex.a_entry & 0xfffff000;
 437
 438         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 439                 static unsigned long error_time;
 440                 loff_t pos = N_TXTOFF(ex);
 441
 442                 if ((jiffies-error_time) > 5*HZ)
 443                 {
 444                         printk(KERN_WARNING
 445                                "N_TXTOFF is not page aligned. Please convert library: %s\n",
 446                                file->f_dentry->d_name.name);
 447                         error_time = jiffies;
 448                 }
 449
 450                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 451
 452                 file->f_op->read(file, (char *)start_addr,
 453                         ex.a_text + ex.a_data, &pos);
 454                 flush_icache_range((unsigned long) start_addr,
 455                                    (unsigned long) start_addr + ex.a_text + ex.a_data);
 456
 457                 retval = 0;
 458                 goto out;
 459         }
 460         /* Now use mmap to map the library into memory. */
 461         down(&current->mm->mmap_sem);
 462         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 463                         PROT_READ | PROT_WRITE | PROT_EXEC,
 464                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 465                         N_TXTOFF(ex));
 466         up(&current->mm->mmap_sem);
 467         retval = error;
 468         if (error != start_addr)
 469                 goto out;
 470
 471         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 472         bss = ex.a_text + ex.a_data + ex.a_bss;
 473         if (bss > len) {
 474                 error = do_brk(start_addr + len, bss - len);
 475                 retval = error;
 476                 if (error != start_addr + len)
 477                         goto out;
 478         }
 479         retval = 0;
 480 out:
 481         return retval;
 482 }
 483
 484 static int __init init_aout_binfmt(void)
 485 {
 486         return register_binfmt(&aout_format);
 487 }
 488
 489 static void __exit exit_aout_binfmt(void)
 490 {
 491         unregister_binfmt(&aout_format);
 492 }
 493
 494 EXPORT_NO_SYMBOLS;
 495
 496 module_init(init_aout_binfmt);
 497 module_exit(exit_aout_binfmt);