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TOMOYO Linux Cross Reference
Linux/fs/binfmt_flat.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /****************************************************************************/
  3 /*
  4  *  linux/fs/binfmt_flat.c
  5  *
  6  *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
  7  *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
  8  *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
  9  *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
 10  *  based heavily on:
 11  *
 12  *  linux/fs/binfmt_aout.c:
 13  *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
 14  *  linux/fs/binfmt_flat.c for 2.0 kernel
 15  *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
 16  *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
 17  */
 18 
 19 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
 20 
 21 #include <linux/kernel.h>
 22 #include <linux/sched.h>
 23 #include <linux/sched/task_stack.h>
 24 #include <linux/mm.h>
 25 #include <linux/mman.h>
 26 #include <linux/errno.h>
 27 #include <linux/signal.h>
 28 #include <linux/string.h>
 29 #include <linux/fs.h>
 30 #include <linux/file.h>
 31 #include <linux/ptrace.h>
 32 #include <linux/user.h>
 33 #include <linux/slab.h>
 34 #include <linux/binfmts.h>
 35 #include <linux/personality.h>
 36 #include <linux/init.h>
 37 #include <linux/flat.h>
 38 #include <linux/uaccess.h>
 39 #include <linux/vmalloc.h>
 40 
 41 #include <asm/byteorder.h>
 42 #include <asm/unaligned.h>
 43 #include <asm/cacheflush.h>
 44 #include <asm/page.h>
 45 #include <asm/flat.h>
 46 
 47 #ifndef flat_get_relocate_addr
 48 #define flat_get_relocate_addr(rel)     (rel)
 49 #endif
 50 
 51 /****************************************************************************/
 52 
 53 /*
 54  * User data (data section and bss) needs to be aligned.
 55  * We pick 0x20 here because it is the max value elf2flt has always
 56  * used in producing FLAT files, and because it seems to be large
 57  * enough to make all the gcc alignment related tests happy.
 58  */
 59 #define FLAT_DATA_ALIGN (0x20)
 60 
 61 /*
 62  * User data (stack) also needs to be aligned.
 63  * Here we can be a bit looser than the data sections since this
 64  * needs to only meet arch ABI requirements.
 65  */
 66 #define FLAT_STACK_ALIGN        max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
 67 
 68 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
 69 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
 70 
 71 #ifdef CONFIG_BINFMT_SHARED_FLAT
 72 #define MAX_SHARED_LIBS                 (4)
 73 #else
 74 #define MAX_SHARED_LIBS                 (1)
 75 #endif
 76 
 77 struct lib_info {
 78         struct {
 79                 unsigned long start_code;               /* Start of text segment */
 80                 unsigned long start_data;               /* Start of data segment */
 81                 unsigned long start_brk;                /* End of data segment */
 82                 unsigned long text_len;                 /* Length of text segment */
 83                 unsigned long entry;                    /* Start address for this module */
 84                 unsigned long build_date;               /* When this one was compiled */
 85                 bool loaded;                            /* Has this library been loaded? */
 86         } lib_list[MAX_SHARED_LIBS];
 87 };
 88 
 89 #ifdef CONFIG_BINFMT_SHARED_FLAT
 90 static int load_flat_shared_library(int id, struct lib_info *p);
 91 #endif
 92 
 93 static int load_flat_binary(struct linux_binprm *);
 94 static int flat_core_dump(struct coredump_params *cprm);
 95 
 96 static struct linux_binfmt flat_format = {
 97         .module         = THIS_MODULE,
 98         .load_binary    = load_flat_binary,
 99         .core_dump      = flat_core_dump,
100         .min_coredump   = PAGE_SIZE
101 };
102 
103 /****************************************************************************/
104 /*
105  * Routine writes a core dump image in the current directory.
106  * Currently only a stub-function.
107  */
108 
109 static int flat_core_dump(struct coredump_params *cprm)
110 {
111         pr_warn("Process %s:%d received signr %d and should have core dumped\n",
112                 current->comm, current->pid, cprm->siginfo->si_signo);
113         return 1;
114 }
115 
116 /****************************************************************************/
117 /*
118  * create_flat_tables() parses the env- and arg-strings in new user
119  * memory and creates the pointer tables from them, and puts their
120  * addresses on the "stack", recording the new stack pointer value.
121  */
122 
123 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
124 {
125         char __user *p;
126         unsigned long __user *sp;
127         long i, len;
128 
129         p = (char __user *)arg_start;
130         sp = (unsigned long __user *)current->mm->start_stack;
131 
132         sp -= bprm->envc + 1;
133         sp -= bprm->argc + 1;
134         if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))
135                 sp -= 2; /* argvp + envp */
136         sp -= 1;  /* &argc */
137 
138         current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
139         sp = (unsigned long __user *)current->mm->start_stack;
140 
141         __put_user(bprm->argc, sp++);
142         if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
143                 unsigned long argv, envp;
144                 argv = (unsigned long)(sp + 2);
145                 envp = (unsigned long)(sp + 2 + bprm->argc + 1);
146                 __put_user(argv, sp++);
147                 __put_user(envp, sp++);
148         }
149 
150         current->mm->arg_start = (unsigned long)p;
151         for (i = bprm->argc; i > 0; i--) {
152                 __put_user((unsigned long)p, sp++);
153                 len = strnlen_user(p, MAX_ARG_STRLEN);
154                 if (!len || len > MAX_ARG_STRLEN)
155                         return -EINVAL;
156                 p += len;
157         }
158         __put_user(0, sp++);
159         current->mm->arg_end = (unsigned long)p;
160 
161         current->mm->env_start = (unsigned long) p;
162         for (i = bprm->envc; i > 0; i--) {
163                 __put_user((unsigned long)p, sp++);
164                 len = strnlen_user(p, MAX_ARG_STRLEN);
165                 if (!len || len > MAX_ARG_STRLEN)
166                         return -EINVAL;
167                 p += len;
168         }
169         __put_user(0, sp++);
170         current->mm->env_end = (unsigned long)p;
171 
172         return 0;
173 }
174 
175 /****************************************************************************/
176 
177 #ifdef CONFIG_BINFMT_ZFLAT
178 
179 #include <linux/zlib.h>
180 
181 #define LBUFSIZE        4000
182 
183 /* gzip flag byte */
184 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
185 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
186 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
187 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
188 #define COMMENT      0x10 /* bit 4 set: file comment present */
189 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
190 #define RESERVED     0xC0 /* bit 6,7:   reserved */
191 
192 static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
193                 long len, int fd)
194 {
195         unsigned char *buf;
196         z_stream strm;
197         int ret, retval;
198 
199         pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
200 
201         memset(&strm, 0, sizeof(strm));
202         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
203         if (!strm.workspace)
204                 return -ENOMEM;
205 
206         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
207         if (!buf) {
208                 retval = -ENOMEM;
209                 goto out_free;
210         }
211 
212         /* Read in first chunk of data and parse gzip header. */
213         ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
214 
215         strm.next_in = buf;
216         strm.avail_in = ret;
217         strm.total_in = 0;
218 
219         retval = -ENOEXEC;
220 
221         /* Check minimum size -- gzip header */
222         if (ret < 10) {
223                 pr_debug("file too small?\n");
224                 goto out_free_buf;
225         }
226 
227         /* Check gzip magic number */
228         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
229                 pr_debug("unknown compression magic?\n");
230                 goto out_free_buf;
231         }
232 
233         /* Check gzip method */
234         if (buf[2] != 8) {
235                 pr_debug("unknown compression method?\n");
236                 goto out_free_buf;
237         }
238         /* Check gzip flags */
239         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
240             (buf[3] & RESERVED)) {
241                 pr_debug("unknown flags?\n");
242                 goto out_free_buf;
243         }
244 
245         ret = 10;
246         if (buf[3] & EXTRA_FIELD) {
247                 ret += 2 + buf[10] + (buf[11] << 8);
248                 if (unlikely(ret >= LBUFSIZE)) {
249                         pr_debug("buffer overflow (EXTRA)?\n");
250                         goto out_free_buf;
251                 }
252         }
253         if (buf[3] & ORIG_NAME) {
254                 while (ret < LBUFSIZE && buf[ret++] != 0)
255                         ;
256                 if (unlikely(ret == LBUFSIZE)) {
257                         pr_debug("buffer overflow (ORIG_NAME)?\n");
258                         goto out_free_buf;
259                 }
260         }
261         if (buf[3] & COMMENT) {
262                 while (ret < LBUFSIZE && buf[ret++] != 0)
263                         ;
264                 if (unlikely(ret == LBUFSIZE)) {
265                         pr_debug("buffer overflow (COMMENT)?\n");
266                         goto out_free_buf;
267                 }
268         }
269 
270         strm.next_in += ret;
271         strm.avail_in -= ret;
272 
273         strm.next_out = dst;
274         strm.avail_out = len;
275         strm.total_out = 0;
276 
277         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
278                 pr_debug("zlib init failed?\n");
279                 goto out_free_buf;
280         }
281 
282         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
283                 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
284                 if (ret <= 0)
285                         break;
286                 len -= ret;
287 
288                 strm.next_in = buf;
289                 strm.avail_in = ret;
290                 strm.total_in = 0;
291         }
292 
293         if (ret < 0) {
294                 pr_debug("decompression failed (%d), %s\n",
295                         ret, strm.msg);
296                 goto out_zlib;
297         }
298 
299         retval = 0;
300 out_zlib:
301         zlib_inflateEnd(&strm);
302 out_free_buf:
303         kfree(buf);
304 out_free:
305         kfree(strm.workspace);
306         return retval;
307 }
308 
309 #endif /* CONFIG_BINFMT_ZFLAT */
310 
311 /****************************************************************************/
312 
313 static unsigned long
314 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
315 {
316         unsigned long addr;
317         int id;
318         unsigned long start_brk;
319         unsigned long start_data;
320         unsigned long text_len;
321         unsigned long start_code;
322 
323 #ifdef CONFIG_BINFMT_SHARED_FLAT
324         if (r == 0)
325                 id = curid;     /* Relocs of 0 are always self referring */
326         else {
327                 id = (r >> 24) & 0xff;  /* Find ID for this reloc */
328                 r &= 0x00ffffff;        /* Trim ID off here */
329         }
330         if (id >= MAX_SHARED_LIBS) {
331                 pr_err("reference 0x%lx to shared library %d", r, id);
332                 goto failed;
333         }
334         if (curid != id) {
335                 if (internalp) {
336                         pr_err("reloc address 0x%lx not in same module "
337                                "(%d != %d)", r, curid, id);
338                         goto failed;
339                 } else if (!p->lib_list[id].loaded &&
340                            load_flat_shared_library(id, p) < 0) {
341                         pr_err("failed to load library %d", id);
342                         goto failed;
343                 }
344                 /* Check versioning information (i.e. time stamps) */
345                 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
346                                 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
347                         pr_err("library %d is younger than %d", id, curid);
348                         goto failed;
349                 }
350         }
351 #else
352         id = 0;
353 #endif
354 
355         start_brk = p->lib_list[id].start_brk;
356         start_data = p->lib_list[id].start_data;
357         start_code = p->lib_list[id].start_code;
358         text_len = p->lib_list[id].text_len;
359 
360         if (r > start_brk - start_data + text_len) {
361                 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
362                        r, start_brk-start_data+text_len, text_len);
363                 goto failed;
364         }
365 
366         if (r < text_len)                       /* In text segment */
367                 addr = r + start_code;
368         else                                    /* In data segment */
369                 addr = r - text_len + start_data;
370 
371         /* Range checked already above so doing the range tests is redundant...*/
372         return addr;
373 
374 failed:
375         pr_cont(", killing %s!\n", current->comm);
376         send_sig(SIGSEGV, current, 0);
377 
378         return RELOC_FAILED;
379 }
380 
381 /****************************************************************************/
382 
383 #ifdef CONFIG_BINFMT_FLAT_OLD
384 static void old_reloc(unsigned long rl)
385 {
386         static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
387         flat_v2_reloc_t r;
388         unsigned long __user *ptr;
389         unsigned long val;
390 
391         r.value = rl;
392 #if defined(CONFIG_COLDFIRE)
393         ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
394 #else
395         ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
396 #endif
397         get_user(val, ptr);
398 
399         pr_debug("Relocation of variable at DATASEG+%x "
400                  "(address %p, currently %lx) into segment %s\n",
401                  r.reloc.offset, ptr, val, segment[r.reloc.type]);
402 
403         switch (r.reloc.type) {
404         case OLD_FLAT_RELOC_TYPE_TEXT:
405                 val += current->mm->start_code;
406                 break;
407         case OLD_FLAT_RELOC_TYPE_DATA:
408                 val += current->mm->start_data;
409                 break;
410         case OLD_FLAT_RELOC_TYPE_BSS:
411                 val += current->mm->end_data;
412                 break;
413         default:
414                 pr_err("Unknown relocation type=%x\n", r.reloc.type);
415                 break;
416         }
417         put_user(val, ptr);
418 
419         pr_debug("Relocation became %lx\n", val);
420 }
421 #endif /* CONFIG_BINFMT_FLAT_OLD */
422 
423 /****************************************************************************/
424 
425 static int load_flat_file(struct linux_binprm *bprm,
426                 struct lib_info *libinfo, int id, unsigned long *extra_stack)
427 {
428         struct flat_hdr *hdr;
429         unsigned long textpos, datapos, realdatastart;
430         u32 text_len, data_len, bss_len, stack_len, full_data, flags;
431         unsigned long len, memp, memp_size, extra, rlim;
432         __be32 __user *reloc;
433         u32 __user *rp;
434         int i, rev, relocs;
435         loff_t fpos;
436         unsigned long start_code, end_code;
437         ssize_t result;
438         int ret;
439 
440         hdr = ((struct flat_hdr *) bprm->buf);          /* exec-header */
441 
442         text_len  = ntohl(hdr->data_start);
443         data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
444         bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
445         stack_len = ntohl(hdr->stack_size);
446         if (extra_stack) {
447                 stack_len += *extra_stack;
448                 *extra_stack = stack_len;
449         }
450         relocs    = ntohl(hdr->reloc_count);
451         flags     = ntohl(hdr->flags);
452         rev       = ntohl(hdr->rev);
453         full_data = data_len + relocs * sizeof(unsigned long);
454 
455         if (strncmp(hdr->magic, "bFLT", 4)) {
456                 /*
457                  * Previously, here was a printk to tell people
458                  *   "BINFMT_FLAT: bad header magic".
459                  * But for the kernel which also use ELF FD-PIC format, this
460                  * error message is confusing.
461                  * because a lot of people do not manage to produce good
462                  */
463                 ret = -ENOEXEC;
464                 goto err;
465         }
466 
467         if (flags & FLAT_FLAG_KTRACE)
468                 pr_info("Loading file: %s\n", bprm->filename);
469 
470 #ifdef CONFIG_BINFMT_FLAT_OLD
471         if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
472                 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
473                        rev, FLAT_VERSION, OLD_FLAT_VERSION);
474                 ret = -ENOEXEC;
475                 goto err;
476         }
477 
478         /* Don't allow old format executables to use shared libraries */
479         if (rev == OLD_FLAT_VERSION && id != 0) {
480                 pr_err("shared libraries are not available before rev 0x%lx\n",
481                        FLAT_VERSION);
482                 ret = -ENOEXEC;
483                 goto err;
484         }
485 
486         /*
487          * fix up the flags for the older format,  there were all kinds
488          * of endian hacks,  this only works for the simple cases
489          */
490         if (rev == OLD_FLAT_VERSION &&
491            (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
492                 flags = FLAT_FLAG_RAM;
493 
494 #else /* CONFIG_BINFMT_FLAT_OLD */
495         if (rev != FLAT_VERSION) {
496                 pr_err("bad flat file version 0x%x (supported 0x%lx)\n",
497                        rev, FLAT_VERSION);
498                 ret = -ENOEXEC;
499                 goto err;
500         }
501 #endif /* !CONFIG_BINFMT_FLAT_OLD */
502 
503         /*
504          * Make sure the header params are sane.
505          * 28 bits (256 MB) is way more than reasonable in this case.
506          * If some top bits are set we have probable binary corruption.
507         */
508         if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
509                 pr_err("bad header\n");
510                 ret = -ENOEXEC;
511                 goto err;
512         }
513 
514 #ifndef CONFIG_BINFMT_ZFLAT
515         if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
516                 pr_err("Support for ZFLAT executables is not enabled.\n");
517                 ret = -ENOEXEC;
518                 goto err;
519         }
520 #endif
521 
522         /*
523          * Check initial limits. This avoids letting people circumvent
524          * size limits imposed on them by creating programs with large
525          * arrays in the data or bss.
526          */
527         rlim = rlimit(RLIMIT_DATA);
528         if (rlim >= RLIM_INFINITY)
529                 rlim = ~0;
530         if (data_len + bss_len > rlim) {
531                 ret = -ENOMEM;
532                 goto err;
533         }
534 
535         /* Flush all traces of the currently running executable */
536         if (id == 0) {
537                 ret = flush_old_exec(bprm);
538                 if (ret)
539                         goto err;
540 
541                 /* OK, This is the point of no return */
542                 set_personality(PER_LINUX_32BIT);
543                 setup_new_exec(bprm);
544         }
545 
546         /*
547          * calculate the extra space we need to map in
548          */
549         extra = max_t(unsigned long, bss_len + stack_len,
550                         relocs * sizeof(unsigned long));
551 
552         /*
553          * there are a couple of cases here,  the separate code/data
554          * case,  and then the fully copied to RAM case which lumps
555          * it all together.
556          */
557         if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
558                 /*
559                  * this should give us a ROM ptr,  but if it doesn't we don't
560                  * really care
561                  */
562                 pr_debug("ROM mapping of file (we hope)\n");
563 
564                 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
565                                   MAP_PRIVATE|MAP_EXECUTABLE, 0);
566                 if (!textpos || IS_ERR_VALUE(textpos)) {
567                         ret = textpos;
568                         if (!textpos)
569                                 ret = -ENOMEM;
570                         pr_err("Unable to mmap process text, errno %d\n", ret);
571                         goto err;
572                 }
573 
574                 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
575                 len = PAGE_ALIGN(len);
576                 realdatastart = vm_mmap(NULL, 0, len,
577                         PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
578 
579                 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
580                         ret = realdatastart;
581                         if (!realdatastart)
582                                 ret = -ENOMEM;
583                         pr_err("Unable to allocate RAM for process data, "
584                                "errno %d\n", ret);
585                         vm_munmap(textpos, text_len);
586                         goto err;
587                 }
588                 datapos = ALIGN(realdatastart +
589                                 MAX_SHARED_LIBS * sizeof(unsigned long),
590                                 FLAT_DATA_ALIGN);
591 
592                 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
593                          data_len + bss_len + stack_len, datapos);
594 
595                 fpos = ntohl(hdr->data_start);
596 #ifdef CONFIG_BINFMT_ZFLAT
597                 if (flags & FLAT_FLAG_GZDATA) {
598                         result = decompress_exec(bprm, fpos, (char *)datapos,
599                                                  full_data, 0);
600                 } else
601 #endif
602                 {
603                         result = read_code(bprm->file, datapos, fpos,
604                                         full_data);
605                 }
606                 if (IS_ERR_VALUE(result)) {
607                         ret = result;
608                         pr_err("Unable to read data+bss, errno %d\n", ret);
609                         vm_munmap(textpos, text_len);
610                         vm_munmap(realdatastart, len);
611                         goto err;
612                 }
613 
614                 reloc = (__be32 __user *)
615                         (datapos + (ntohl(hdr->reloc_start) - text_len));
616                 memp = realdatastart;
617                 memp_size = len;
618         } else {
619 
620                 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32);
621                 len = PAGE_ALIGN(len);
622                 textpos = vm_mmap(NULL, 0, len,
623                         PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
624 
625                 if (!textpos || IS_ERR_VALUE(textpos)) {
626                         ret = textpos;
627                         if (!textpos)
628                                 ret = -ENOMEM;
629                         pr_err("Unable to allocate RAM for process text/data, "
630                                "errno %d\n", ret);
631                         goto err;
632                 }
633 
634                 realdatastart = textpos + ntohl(hdr->data_start);
635                 datapos = ALIGN(realdatastart +
636                                 MAX_SHARED_LIBS * sizeof(u32),
637                                 FLAT_DATA_ALIGN);
638 
639                 reloc = (__be32 __user *)
640                         (datapos + (ntohl(hdr->reloc_start) - text_len));
641                 memp = textpos;
642                 memp_size = len;
643 #ifdef CONFIG_BINFMT_ZFLAT
644                 /*
645                  * load it all in and treat it like a RAM load from now on
646                  */
647                 if (flags & FLAT_FLAG_GZIP) {
648 #ifndef CONFIG_MMU
649                         result = decompress_exec(bprm, sizeof(struct flat_hdr),
650                                          (((char *)textpos) + sizeof(struct flat_hdr)),
651                                          (text_len + full_data
652                                                   - sizeof(struct flat_hdr)),
653                                          0);
654                         memmove((void *) datapos, (void *) realdatastart,
655                                         full_data);
656 #else
657                         /*
658                          * This is used on MMU systems mainly for testing.
659                          * Let's use a kernel buffer to simplify things.
660                          */
661                         long unz_text_len = text_len - sizeof(struct flat_hdr);
662                         long unz_len = unz_text_len + full_data;
663                         char *unz_data = vmalloc(unz_len);
664                         if (!unz_data) {
665                                 result = -ENOMEM;
666                         } else {
667                                 result = decompress_exec(bprm, sizeof(struct flat_hdr),
668                                                          unz_data, unz_len, 0);
669                                 if (result == 0 &&
670                                     (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
671                                                   unz_data, unz_text_len) ||
672                                      copy_to_user((void __user *)datapos,
673                                                   unz_data + unz_text_len, full_data)))
674                                         result = -EFAULT;
675                                 vfree(unz_data);
676                         }
677 #endif
678                 } else if (flags & FLAT_FLAG_GZDATA) {
679                         result = read_code(bprm->file, textpos, 0, text_len);
680                         if (!IS_ERR_VALUE(result)) {
681 #ifndef CONFIG_MMU
682                                 result = decompress_exec(bprm, text_len, (char *) datapos,
683                                                  full_data, 0);
684 #else
685                                 char *unz_data = vmalloc(full_data);
686                                 if (!unz_data) {
687                                         result = -ENOMEM;
688                                 } else {
689                                         result = decompress_exec(bprm, text_len,
690                                                        unz_data, full_data, 0);
691                                         if (result == 0 &&
692                                             copy_to_user((void __user *)datapos,
693                                                          unz_data, full_data))
694                                                 result = -EFAULT;
695                                         vfree(unz_data);
696                                 }
697 #endif
698                         }
699                 } else
700 #endif /* CONFIG_BINFMT_ZFLAT */
701                 {
702                         result = read_code(bprm->file, textpos, 0, text_len);
703                         if (!IS_ERR_VALUE(result))
704                                 result = read_code(bprm->file, datapos,
705                                                    ntohl(hdr->data_start),
706                                                    full_data);
707                 }
708                 if (IS_ERR_VALUE(result)) {
709                         ret = result;
710                         pr_err("Unable to read code+data+bss, errno %d\n", ret);
711                         vm_munmap(textpos, text_len + data_len + extra +
712                                 MAX_SHARED_LIBS * sizeof(u32));
713                         goto err;
714                 }
715         }
716 
717         start_code = textpos + sizeof(struct flat_hdr);
718         end_code = textpos + text_len;
719         text_len -= sizeof(struct flat_hdr); /* the real code len */
720 
721         /* The main program needs a little extra setup in the task structure */
722         if (id == 0) {
723                 current->mm->start_code = start_code;
724                 current->mm->end_code = end_code;
725                 current->mm->start_data = datapos;
726                 current->mm->end_data = datapos + data_len;
727                 /*
728                  * set up the brk stuff, uses any slack left in data/bss/stack
729                  * allocation.  We put the brk after the bss (between the bss
730                  * and stack) like other platforms.
731                  * Userspace code relies on the stack pointer starting out at
732                  * an address right at the end of a page.
733                  */
734                 current->mm->start_brk = datapos + data_len + bss_len;
735                 current->mm->brk = (current->mm->start_brk + 3) & ~3;
736 #ifndef CONFIG_MMU
737                 current->mm->context.end_brk = memp + memp_size - stack_len;
738 #endif
739         }
740 
741         if (flags & FLAT_FLAG_KTRACE) {
742                 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
743                         textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
744                 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
745                         id ? "Lib" : "Load", bprm->filename,
746                         start_code, end_code, datapos, datapos + data_len,
747                         datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
748         }
749 
750         /* Store the current module values into the global library structure */
751         libinfo->lib_list[id].start_code = start_code;
752         libinfo->lib_list[id].start_data = datapos;
753         libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
754         libinfo->lib_list[id].text_len = text_len;
755         libinfo->lib_list[id].loaded = 1;
756         libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
757         libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
758 
759         /*
760          * We just load the allocations into some temporary memory to
761          * help simplify all this mumbo jumbo
762          *
763          * We've got two different sections of relocation entries.
764          * The first is the GOT which resides at the beginning of the data segment
765          * and is terminated with a -1.  This one can be relocated in place.
766          * The second is the extra relocation entries tacked after the image's
767          * data segment. These require a little more processing as the entry is
768          * really an offset into the image which contains an offset into the
769          * image.
770          */
771         if (flags & FLAT_FLAG_GOTPIC) {
772                 for (rp = (u32 __user *)datapos; ; rp++) {
773                         u32 addr, rp_val;
774                         if (get_user(rp_val, rp))
775                                 return -EFAULT;
776                         if (rp_val == 0xffffffff)
777                                 break;
778                         if (rp_val) {
779                                 addr = calc_reloc(rp_val, libinfo, id, 0);
780                                 if (addr == RELOC_FAILED) {
781                                         ret = -ENOEXEC;
782                                         goto err;
783                                 }
784                                 if (put_user(addr, rp))
785                                         return -EFAULT;
786                         }
787                 }
788         }
789 
790         /*
791          * Now run through the relocation entries.
792          * We've got to be careful here as C++ produces relocatable zero
793          * entries in the constructor and destructor tables which are then
794          * tested for being not zero (which will always occur unless we're
795          * based from address zero).  This causes an endless loop as __start
796          * is at zero.  The solution used is to not relocate zero addresses.
797          * This has the negative side effect of not allowing a global data
798          * reference to be statically initialised to _stext (I've moved
799          * __start to address 4 so that is okay).
800          */
801         if (rev > OLD_FLAT_VERSION) {
802                 for (i = 0; i < relocs; i++) {
803                         u32 addr, relval;
804                         __be32 tmp;
805 
806                         /*
807                          * Get the address of the pointer to be
808                          * relocated (of course, the address has to be
809                          * relocated first).
810                          */
811                         if (get_user(tmp, reloc + i))
812                                 return -EFAULT;
813                         relval = ntohl(tmp);
814                         addr = flat_get_relocate_addr(relval);
815                         rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
816                         if (rp == (u32 __user *)RELOC_FAILED) {
817                                 ret = -ENOEXEC;
818                                 goto err;
819                         }
820 
821                         /* Get the pointer's value.  */
822                         ret = flat_get_addr_from_rp(rp, relval, flags, &addr);
823                         if (unlikely(ret))
824                                 goto err;
825 
826                         if (addr != 0) {
827                                 /*
828                                  * Do the relocation.  PIC relocs in the data section are
829                                  * already in target order
830                                  */
831                                 if ((flags & FLAT_FLAG_GOTPIC) == 0) {
832                                         /*
833                                          * Meh, the same value can have a different
834                                          * byte order based on a flag..
835                                          */
836                                         addr = ntohl((__force __be32)addr);
837                                 }
838                                 addr = calc_reloc(addr, libinfo, id, 0);
839                                 if (addr == RELOC_FAILED) {
840                                         ret = -ENOEXEC;
841                                         goto err;
842                                 }
843 
844                                 /* Write back the relocated pointer.  */
845                                 ret = flat_put_addr_at_rp(rp, addr, relval);
846                                 if (unlikely(ret))
847                                         goto err;
848                         }
849                 }
850 #ifdef CONFIG_BINFMT_FLAT_OLD
851         } else {
852                 for (i = 0; i < relocs; i++) {
853                         __be32 relval;
854                         if (get_user(relval, reloc + i))
855                                 return -EFAULT;
856                         old_reloc(ntohl(relval));
857                 }
858 #endif /* CONFIG_BINFMT_FLAT_OLD */
859         }
860 
861         flush_icache_range(start_code, end_code);
862 
863         /* zero the BSS,  BRK and stack areas */
864         if (clear_user((void __user *)(datapos + data_len), bss_len +
865                        (memp + memp_size - stack_len -          /* end brk */
866                        libinfo->lib_list[id].start_brk) +       /* start brk */
867                        stack_len))
868                 return -EFAULT;
869 
870         return 0;
871 err:
872         return ret;
873 }
874 
875 
876 /****************************************************************************/
877 #ifdef CONFIG_BINFMT_SHARED_FLAT
878 
879 /*
880  * Load a shared library into memory.  The library gets its own data
881  * segment (including bss) but not argv/argc/environ.
882  */
883 
884 static int load_flat_shared_library(int id, struct lib_info *libs)
885 {
886         /*
887          * This is a fake bprm struct; only the members "buf", "file" and
888          * "filename" are actually used.
889          */
890         struct linux_binprm bprm;
891         int res;
892         char buf[16];
893         loff_t pos = 0;
894 
895         memset(&bprm, 0, sizeof(bprm));
896 
897         /* Create the file name */
898         sprintf(buf, "/lib/lib%d.so", id);
899 
900         /* Open the file up */
901         bprm.filename = buf;
902         bprm.file = open_exec(bprm.filename);
903         res = PTR_ERR(bprm.file);
904         if (IS_ERR(bprm.file))
905                 return res;
906 
907         res = kernel_read(bprm.file, bprm.buf, BINPRM_BUF_SIZE, &pos);
908 
909         if (res >= 0)
910                 res = load_flat_file(&bprm, libs, id, NULL);
911 
912         allow_write_access(bprm.file);
913         fput(bprm.file);
914 
915         return res;
916 }
917 
918 #endif /* CONFIG_BINFMT_SHARED_FLAT */
919 /****************************************************************************/
920 
921 /*
922  * These are the functions used to load flat style executables and shared
923  * libraries.  There is no binary dependent code anywhere else.
924  */
925 
926 static int load_flat_binary(struct linux_binprm *bprm)
927 {
928         struct lib_info libinfo;
929         struct pt_regs *regs = current_pt_regs();
930         unsigned long stack_len = 0;
931         unsigned long start_addr;
932         int res;
933         int i, j;
934 
935         memset(&libinfo, 0, sizeof(libinfo));
936 
937         /*
938          * We have to add the size of our arguments to our stack size
939          * otherwise it's too easy for users to create stack overflows
940          * by passing in a huge argument list.  And yes,  we have to be
941          * pedantic and include space for the argv/envp array as it may have
942          * a lot of entries.
943          */
944 #ifndef CONFIG_MMU
945         stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
946 #endif
947         stack_len += (bprm->argc + 1) * sizeof(char *);   /* the argv array */
948         stack_len += (bprm->envc + 1) * sizeof(char *);   /* the envp array */
949         stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
950 
951         res = load_flat_file(bprm, &libinfo, 0, &stack_len);
952         if (res < 0)
953                 return res;
954 
955         /* Update data segment pointers for all libraries */
956         for (i = 0; i < MAX_SHARED_LIBS; i++) {
957                 if (!libinfo.lib_list[i].loaded)
958                         continue;
959                 for (j = 0; j < MAX_SHARED_LIBS; j++) {
960                         unsigned long val = libinfo.lib_list[j].loaded ?
961                                 libinfo.lib_list[j].start_data : UNLOADED_LIB;
962                         unsigned long __user *p = (unsigned long __user *)
963                                 libinfo.lib_list[i].start_data;
964                         p -= j + 1;
965                         if (put_user(val, p))
966                                 return -EFAULT;
967                 }
968         }
969 
970         install_exec_creds(bprm);
971 
972         set_binfmt(&flat_format);
973 
974 #ifdef CONFIG_MMU
975         res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
976         if (!res)
977                 res = create_flat_tables(bprm, bprm->p);
978 #else
979         /* Stash our initial stack pointer into the mm structure */
980         current->mm->start_stack =
981                 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
982         pr_debug("sp=%lx\n", current->mm->start_stack);
983 
984         /* copy the arg pages onto the stack */
985         res = transfer_args_to_stack(bprm, &current->mm->start_stack);
986         if (!res)
987                 res = create_flat_tables(bprm, current->mm->start_stack);
988 #endif
989         if (res)
990                 return res;
991 
992         /* Fake some return addresses to ensure the call chain will
993          * initialise library in order for us.  We are required to call
994          * lib 1 first, then 2, ... and finally the main program (id 0).
995          */
996         start_addr = libinfo.lib_list[0].entry;
997 
998 #ifdef CONFIG_BINFMT_SHARED_FLAT
999         for (i = MAX_SHARED_LIBS-1; i > 0; i--) {
1000                 if (libinfo.lib_list[i].loaded) {
1001                         /* Push previos first to call address */
1002                         unsigned long __user *sp;
1003                         current->mm->start_stack -= sizeof(unsigned long);
1004                         sp = (unsigned long __user *)current->mm->start_stack;
1005                         __put_user(start_addr, sp);
1006                         start_addr = libinfo.lib_list[i].entry;
1007                 }
1008         }
1009 #endif
1010 
1011 #ifdef FLAT_PLAT_INIT
1012         FLAT_PLAT_INIT(regs);
1013 #endif
1014 
1015         finalize_exec(bprm);
1016         pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
1017                  regs, start_addr, current->mm->start_stack);
1018         start_thread(regs, start_addr, current->mm->start_stack);
1019 
1020         return 0;
1021 }
1022 
1023 /****************************************************************************/
1024 
1025 static int __init init_flat_binfmt(void)
1026 {
1027         register_binfmt(&flat_format);
1028         return 0;
1029 }
1030 core_initcall(init_flat_binfmt);
1031 
1032 /****************************************************************************/
1033 

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