Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/fs/binfmt_flat.c

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

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us