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   1 /*
   2  *  linux/fs/binfmt_aout.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
   5  *
   6  *  Hacked a bit by DaveM to make it work with 32-bit SunOS
   7  *  binaries on the sparc64 port.
   8  */
   9
  10 #include <linux/module.h>
  11
  12 #include <linux/sched.h>
  13 #include <linux/kernel.h>
  14 #include <linux/mm.h>
  15 #include <linux/mman.h>
  16 #include <linux/a.out.h>
  17 #include <linux/errno.h>
  18 #include <linux/signal.h>
  19 #include <linux/string.h>
  20 #include <linux/fs.h>
  21 #include <linux/file.h>
  22 #include <linux/stat.h>
  23 #include <linux/fcntl.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/user.h>
  26 #include <linux/slab.h>
  27 #include <linux/binfmts.h>
  28 #include <linux/personality.h>
  29 #include <linux/init.h>
  30
  31 #include <asm/system.h>
  32 #include <asm/uaccess.h>
  33 #include <asm/pgalloc.h>
  34
  35 static int load_aout32_binary(struct linux_binprm *, struct pt_regs * regs);
  36 static int load_aout32_library(struct file*);
  37 static int aout32_core_dump(long signr, struct pt_regs * regs, struct file *file);
  38
  39 extern void dump_thread(struct pt_regs *, struct user *);
  40
  41 static struct linux_binfmt aout32_format = {
  42         NULL, THIS_MODULE, load_aout32_binary, load_aout32_library, aout32_core_dump,
  43         PAGE_SIZE
  44 };
  45
  46 static void set_brk(unsigned long start, unsigned long end)
  47 {
  48         start = PAGE_ALIGN(start);
  49         end = PAGE_ALIGN(end);
  50         if (end <= start)
  51                 return;
  52         down_write(&current->mm->mmap_sem);
  53         do_brk(start, end - start);
  54         up_write(&current->mm->mmap_sem);
  55 }
  56
  57 /*
  58  * These are the only things you should do on a core-file: use only these
  59  * macros to write out all the necessary info.
  60  */
  61
  62 static int dump_write(struct file *file, const void *addr, int nr)
  63 {
  64         return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
  65 }
  66
  67 #define DUMP_WRITE(addr, nr)    \
  68         if (!dump_write(file, (void *)(addr), (nr))) \
  69                 goto end_coredump;
  70
  71 #define DUMP_SEEK(offset) \
  72 if (file->f_op->llseek) { \
  73         if (file->f_op->llseek(file,(offset),0) != (offset)) \
  74                 goto end_coredump; \
  75 } else file->f_pos = (offset)
  76
  77 /*
  78  * Routine writes a core dump image in the current directory.
  79  * Currently only a stub-function.
  80  *
  81  * Note that setuid/setgid files won't make a core-dump if the uid/gid
  82  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
  83  * field, which also makes sure the core-dumps won't be recursive if the
  84  * dumping of the process results in another error..
  85  */
  86
  87 static int aout32_core_dump(long signr, struct pt_regs *regs, struct file *file)
  88 {
  89         mm_segment_t fs;
  90         int has_dumped = 0;
  91         unsigned long dump_start, dump_size;
  92         struct user dump;
  93 #       define START_DATA(u)    (u.u_tsize)
  94 #       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
  95
  96         fs = get_fs();
  97         set_fs(KERNEL_DS);
  98         has_dumped = 1;
  99         current->flags |= PF_DUMPCORE;
 100         strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
 101         dump.signal = signr;
 102         dump_thread(regs, &dump);
 103
 104 /* If the size of the dump file exceeds the rlimit, then see what would happen
 105    if we wrote the stack, but not the data area.  */
 106         if ((dump.u_dsize+dump.u_ssize) >
 107             current->signal->rlim[RLIMIT_CORE].rlim_cur)
 108                 dump.u_dsize = 0;
 109
 110 /* Make sure we have enough room to write the stack and data areas. */
 111         if ((dump.u_ssize) >
 112             current->signal->rlim[RLIMIT_CORE].rlim_cur)
 113                 dump.u_ssize = 0;
 114
 115 /* make sure we actually have a data and stack area to dump */
 116         set_fs(USER_DS);
 117         if (!access_ok(VERIFY_READ, (void __user *) START_DATA(dump), dump.u_dsize))
 118                 dump.u_dsize = 0;
 119         if (!access_ok(VERIFY_READ, (void __user *) START_STACK(dump), dump.u_ssize))
 120                 dump.u_ssize = 0;
 121
 122         set_fs(KERNEL_DS);
 123 /* struct user */
 124         DUMP_WRITE(&dump,sizeof(dump));
 125 /* now we start writing out the user space info */
 126         set_fs(USER_DS);
 127 /* Dump the data area */
 128         if (dump.u_dsize != 0) {
 129                 dump_start = START_DATA(dump);
 130                 dump_size = dump.u_dsize;
 131                 DUMP_WRITE(dump_start,dump_size);
 132         }
 133 /* Now prepare to dump the stack area */
 134         if (dump.u_ssize != 0) {
 135                 dump_start = START_STACK(dump);
 136                 dump_size = dump.u_ssize;
 137                 DUMP_WRITE(dump_start,dump_size);
 138         }
 139 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 140         set_fs(KERNEL_DS);
 141         DUMP_WRITE(current,sizeof(*current));
 142 end_coredump:
 143         set_fs(fs);
 144         return has_dumped;
 145 }
 146
 147 /*
 148  * create_aout32_tables() parses the env- and arg-strings in new user
 149  * memory and creates the pointer tables from them, and puts their
 150  * addresses on the "stack", returning the new stack pointer value.
 151  */
 152
 153 static u32 __user *create_aout32_tables(char __user *p, struct linux_binprm *bprm)
 154 {
 155         u32 __user *argv;
 156         u32 __user *envp;
 157         u32 __user *sp;
 158         int argc = bprm->argc;
 159         int envc = bprm->envc;
 160
 161         sp = (u32 __user *)((-(unsigned long)sizeof(char *))&(unsigned long)p);
 162
 163         /* This imposes the proper stack alignment for a new process. */
 164         sp = (u32 __user *) (((unsigned long) sp) & ~7);
 165         if ((envc+argc+3)&1)
 166                 --sp;
 167
 168         sp -= envc+1;
 169         envp = sp;
 170         sp -= argc+1;
 171         argv = sp;
 172         put_user(argc,--sp);
 173         current->mm->arg_start = (unsigned long) p;
 174         while (argc-->0) {
 175                 char c;
 176                 put_user(((u32)(unsigned long)(p)),argv++);
 177                 do {
 178                         get_user(c,p++);
 179                 } while (c);
 180         }
 181         put_user(NULL,argv);
 182         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 183         while (envc-->0) {
 184                 char c;
 185                 put_user(((u32)(unsigned long)(p)),envp++);
 186                 do {
 187                         get_user(c,p++);
 188                 } while (c);
 189         }
 190         put_user(NULL,envp);
 191         current->mm->env_end = (unsigned long) p;
 192         return sp;
 193 }
 194
 195 /*
 196  * These are the functions used to load a.out style executables and shared
 197  * libraries.  There is no binary dependent code anywhere else.
 198  */
 199
 200 static int load_aout32_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 201 {
 202         struct exec ex;
 203         unsigned long error;
 204         unsigned long fd_offset;
 205         unsigned long rlim;
 206         unsigned long orig_thr_flags;
 207         int retval;
 208
 209         ex = *((struct exec *) bprm->buf);              /* exec-header */
 210         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 211              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 212             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 213             bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 214                 return -ENOEXEC;
 215         }
 216
 217         fd_offset = N_TXTOFF(ex);
 218
 219         /* Check initial limits. This avoids letting people circumvent
 220          * size limits imposed on them by creating programs with large
 221          * arrays in the data or bss.
 222          */
 223         rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 224         if (rlim >= RLIM_INFINITY)
 225                 rlim = ~0;
 226         if (ex.a_data + ex.a_bss > rlim)
 227                 return -ENOMEM;
 228
 229         /* Flush all traces of the currently running executable */
 230         retval = flush_old_exec(bprm);
 231         if (retval)
 232                 return retval;
 233
 234         /* OK, This is the point of no return */
 235         set_personality(PER_SUNOS);
 236
 237         current->mm->end_code = ex.a_text +
 238                 (current->mm->start_code = N_TXTADDR(ex));
 239         current->mm->end_data = ex.a_data +
 240                 (current->mm->start_data = N_DATADDR(ex));
 241         current->mm->brk = ex.a_bss +
 242                 (current->mm->start_brk = N_BSSADDR(ex));
 243
 244         set_mm_counter(current->mm, rss, 0);
 245         current->mm->mmap = NULL;
 246         compute_creds(bprm);
 247         current->flags &= ~PF_FORKNOEXEC;
 248         if (N_MAGIC(ex) == NMAGIC) {
 249                 loff_t pos = fd_offset;
 250                 /* Fuck me plenty... */
 251                 down_write(&current->mm->mmap_sem);
 252                 error = do_brk(N_TXTADDR(ex), ex.a_text);
 253                 up_write(&current->mm->mmap_sem);
 254                 bprm->file->f_op->read(bprm->file, (char __user *)N_TXTADDR(ex),
 255                           ex.a_text, &pos);
 256                 down_write(&current->mm->mmap_sem);
 257                 error = do_brk(N_DATADDR(ex), ex.a_data);
 258                 up_write(&current->mm->mmap_sem);
 259                 bprm->file->f_op->read(bprm->file, (char __user *)N_DATADDR(ex),
 260                           ex.a_data, &pos);
 261                 goto beyond_if;
 262         }
 263
 264         if (N_MAGIC(ex) == OMAGIC) {
 265                 loff_t pos = fd_offset;
 266                 down_write(&current->mm->mmap_sem);
 267                 do_brk(N_TXTADDR(ex) & PAGE_MASK,
 268                         ex.a_text+ex.a_data + PAGE_SIZE - 1);
 269                 up_write(&current->mm->mmap_sem);
 270                 bprm->file->f_op->read(bprm->file, (char __user *)N_TXTADDR(ex),
 271                           ex.a_text+ex.a_data, &pos);
 272         } else {
 273                 static unsigned long error_time;
 274                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 275                     (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time) > 5*HZ)
 276                 {
 277                         printk(KERN_NOTICE "executable not page aligned\n");
 278                         error_time = jiffies;
 279                 }
 280
 281                 if (!bprm->file->f_op->mmap) {
 282                         loff_t pos = fd_offset;
 283                         down_write(&current->mm->mmap_sem);
 284                         do_brk(0, ex.a_text+ex.a_data);
 285                         up_write(&current->mm->mmap_sem);
 286                         bprm->file->f_op->read(bprm->file,
 287                                   (char __user *)N_TXTADDR(ex),
 288                                   ex.a_text+ex.a_data, &pos);
 289                         goto beyond_if;
 290                 }
 291
 292                 down_write(&current->mm->mmap_sem);
 293                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 294                         PROT_READ | PROT_EXEC,
 295                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 296                         fd_offset);
 297                 up_write(&current->mm->mmap_sem);
 298
 299                 if (error != N_TXTADDR(ex)) {
 300                         send_sig(SIGKILL, current, 0);
 301                         return error;
 302                 }
 303
 304                 down_write(&current->mm->mmap_sem);
 305                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 306                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 307                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
 308                                 fd_offset + ex.a_text);
 309                 up_write(&current->mm->mmap_sem);
 310                 if (error != N_DATADDR(ex)) {
 311                         send_sig(SIGKILL, current, 0);
 312                         return error;
 313                 }
 314         }
 315 beyond_if:
 316         set_binfmt(&aout32_format);
 317
 318         set_brk(current->mm->start_brk, current->mm->brk);
 319
 320         /* Make sure STACK_TOP returns the right thing.  */
 321         orig_thr_flags = current_thread_info()->flags;
 322         current_thread_info()->flags |= _TIF_32BIT;
 323
 324         retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
 325         if (retval < 0) {
 326                 current_thread_info()->flags = orig_thr_flags;
 327
 328                 /* Someone check-me: is this error path enough? */
 329                 send_sig(SIGKILL, current, 0);
 330                 return retval;
 331         }
 332
 333         current->mm->start_stack =
 334                 (unsigned long) create_aout32_tables((char __user *)bprm->p, bprm);
 335         if (!(orig_thr_flags & _TIF_32BIT)) {
 336                 unsigned long pgd_cache = get_pgd_cache(current->mm->pgd);
 337
 338                 __asm__ __volatile__("stxa\t%0, [%1] %2\n\t"
 339                                      "membar #Sync"
 340                                      : /* no outputs */
 341                                      : "r" (pgd_cache),
 342                                        "r" (TSB_REG), "i" (ASI_DMMU));
 343         }
 344         start_thread32(regs, ex.a_entry, current->mm->start_stack);
 345         if (current->ptrace & PT_PTRACED)
 346                 send_sig(SIGTRAP, current, 0);
 347         return 0;
 348 }
 349
 350 /* N.B. Move to .h file and use code in fs/binfmt_aout.c? */
 351 static int load_aout32_library(struct file *file)
 352 {
 353         struct inode * inode;
 354         unsigned long bss, start_addr, len;
 355         unsigned long error;
 356         int retval;
 357         struct exec ex;
 358
 359         inode = file->f_dentry->d_inode;
 360
 361         retval = -ENOEXEC;
 362         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 363         if (error != sizeof(ex))
 364                 goto out;
 365
 366         /* We come in here for the regular a.out style of shared libraries */
 367         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 368             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 369             inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 370                 goto out;
 371         }
 372
 373         if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
 374             (N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
 375                 printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
 376                 goto out;
 377         }
 378
 379         if (N_FLAGS(ex))
 380                 goto out;
 381
 382         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 383            this off to get the starting address for the page */
 384
 385         start_addr =  ex.a_entry & 0xfffff000;
 386
 387         /* Now use mmap to map the library into memory. */
 388         down_write(&current->mm->mmap_sem);
 389         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 390                         PROT_READ | PROT_WRITE | PROT_EXEC,
 391                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
 392                         N_TXTOFF(ex));
 393         up_write(&current->mm->mmap_sem);
 394         retval = error;
 395         if (error != start_addr)
 396                 goto out;
 397
 398         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 399         bss = ex.a_text + ex.a_data + ex.a_bss;
 400         if (bss > len) {
 401                 down_write(&current->mm->mmap_sem);
 402                 error = do_brk(start_addr + len, bss - len);
 403                 up_write(&current->mm->mmap_sem);
 404                 retval = error;
 405                 if (error != start_addr + len)
 406                         goto out;
 407         }
 408         retval = 0;
 409 out:
 410         return retval;
 411 }
 412
 413 static int __init init_aout32_binfmt(void)
 414 {
 415         return register_binfmt(&aout32_format);
 416 }
 417
 418 static void __exit exit_aout32_binfmt(void)
 419 {
 420         unregister_binfmt(&aout32_format);
 421 }
 422
 423 module_init(init_aout32_binfmt);
 424 module_exit(exit_aout32_binfmt);