contrib/file-4/src/readelf.c

   1 /*
   2  * Copyright (c) Christos Zoulas 2003.
   3  * All Rights Reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice immediately at the beginning of the file, without modification,
  10  *    this list of conditions, and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  19  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27 #include "file.h"
  28
  29 #ifdef BUILTIN_ELF
  30 #include <string.h>
  31 #include <ctype.h>
  32 #include <stdlib.h>
  33 #ifdef HAVE_UNISTD_H
  34 #include <unistd.h>
  35 #endif
  36
  37 #include "readelf.h"
  38
  39 #ifndef lint
  40 FILE_RCSID("@(#)$Id: readelf.c,v 1.47 2005/06/25 15:52:14 christos Exp $")
  41 #endif
  42
  43 #ifdef  ELFCORE
  44 private int dophn_core(struct magic_set *, int, int, int, off_t, int, size_t);
  45 #endif
  46 private int dophn_exec(struct magic_set *, int, int, int, off_t, int, size_t);
  47 private int doshn(struct magic_set *, int, int, int, off_t, int, size_t);
  48 private size_t donote(struct magic_set *, unsigned char *, size_t, size_t, int,
  49     int, size_t);
  50
  51 #define ELF_ALIGN(a)    ((((a) + align - 1) / align) * align)
  52
  53 private uint16_t getu16(int, uint16_t);
  54 private uint32_t getu32(int, uint32_t);
  55 private uint64_t getu64(int, uint64_t);
  56
  57 private uint16_t
  58 getu16(int swap, uint16_t value)
  59 {
  60         union {
  61                 uint16_t ui;
  62                 char c[2];
  63         } retval, tmpval;
  64
  65         if (swap) {
  66                 tmpval.ui = value;
  67
  68                 retval.c[0] = tmpval.c[1];
  69                 retval.c[1] = tmpval.c[0];
  70
  71                 return retval.ui;
  72         } else
  73                 return value;
  74 }
  75
  76 private uint32_t
  77 getu32(int swap, uint32_t value)
  78 {
  79         union {
  80                 uint32_t ui;
  81                 char c[4];
  82         } retval, tmpval;
  83
  84         if (swap) {
  85                 tmpval.ui = value;
  86
  87                 retval.c[0] = tmpval.c[3];
  88                 retval.c[1] = tmpval.c[2];
  89                 retval.c[2] = tmpval.c[1];
  90                 retval.c[3] = tmpval.c[0];
  91
  92                 return retval.ui;
  93         } else
  94                 return value;
  95 }
  96
  97 private uint64_t
  98 getu64(int swap, uint64_t value)
  99 {
 100         union {
 101                 uint64_t ui;
 102                 char c[8];
 103         } retval, tmpval;
 104
 105         if (swap) {
 106                 tmpval.ui = value;
 107
 108                 retval.c[0] = tmpval.c[7];
 109                 retval.c[1] = tmpval.c[6];
 110                 retval.c[2] = tmpval.c[5];
 111                 retval.c[3] = tmpval.c[4];
 112                 retval.c[4] = tmpval.c[3];
 113                 retval.c[5] = tmpval.c[2];
 114                 retval.c[6] = tmpval.c[1];
 115                 retval.c[7] = tmpval.c[0];
 116
 117                 return retval.ui;
 118         } else
 119                 return value;
 120 }
 121
 122 #define sh_addr         (class == ELFCLASS32            \
 123                          ? (void *) &sh32               \
 124                          : (void *) &sh64)
 125 #define sh_size         (class == ELFCLASS32            \
 126                          ? sizeof sh32                  \
 127                          : sizeof sh64)
 128 #define shs_type        (class == ELFCLASS32            \
 129                          ? getu32(swap, sh32.sh_type)   \
 130                          : getu32(swap, sh64.sh_type))
 131 #define ph_addr         (class == ELFCLASS32            \
 132                          ? (void *) &ph32               \
 133                          : (void *) &ph64)
 134 #define ph_size         (class == ELFCLASS32            \
 135                          ? sizeof ph32                  \
 136                          : sizeof ph64)
 137 #define ph_type         (class == ELFCLASS32            \
 138                          ? getu32(swap, ph32.p_type)    \
 139                          : getu32(swap, ph64.p_type))
 140 #define ph_offset       (class == ELFCLASS32            \
 141                          ? getu32(swap, ph32.p_offset)  \
 142                          : getu64(swap, ph64.p_offset))
 143 #define ph_align        (size_t)((class == ELFCLASS32   \
 144                          ? (off_t) (ph32.p_align ?      \
 145                             getu32(swap, ph32.p_align) : 4) \
 146                          : (off_t) (ph64.p_align ?      \
 147                             getu64(swap, ph64.p_align) : 4)))
 148 #define ph_filesz       (size_t)((class == ELFCLASS32   \
 149                          ? getu32(swap, ph32.p_filesz)  \
 150                          : getu64(swap, ph64.p_filesz)))
 151 #define ph_memsz        (size_t)((class == ELFCLASS32   \
 152                          ? getu32(swap, ph32.p_memsz)   \
 153                          : getu64(swap, ph64.p_memsz)))
 154 #define nh_size         (class == ELFCLASS32            \
 155                          ? sizeof nh32                  \
 156                          : sizeof nh64)
 157 #define nh_type         (class == ELFCLASS32            \
 158                          ? getu32(swap, nh32.n_type)    \
 159                          : getu32(swap, nh64.n_type))
 160 #define nh_namesz       (class == ELFCLASS32            \
 161                          ? getu32(swap, nh32.n_namesz)  \
 162                          : getu32(swap, nh64.n_namesz))
 163 #define nh_descsz       (class == ELFCLASS32            \
 164                          ? getu32(swap, nh32.n_descsz)  \
 165                          : getu32(swap, nh64.n_descsz))
 166 #define prpsoffsets(i)  (class == ELFCLASS32            \
 167                          ? prpsoffsets32[i]             \
 168                          : prpsoffsets64[i])
 169
 170 #ifdef ELFCORE
 171 size_t  prpsoffsets32[] = {
 172         8,              /* FreeBSD */
 173         28,             /* Linux 2.0.36 */
 174         32,             /* Linux (I forget which kernel version) */
 175         84,             /* SunOS 5.x */
 176 };
 177
 178 size_t  prpsoffsets64[] = {
 179         40,             /* Linux (tested on core from 2.4.x) */
 180        120,             /* SunOS 5.x, 64-bit */
 181 };
 182
 183 #define NOFFSETS32      (sizeof prpsoffsets32 / sizeof prpsoffsets32[0])
 184 #define NOFFSETS64      (sizeof prpsoffsets64 / sizeof prpsoffsets64[0])
 185
 186 #define NOFFSETS        (class == ELFCLASS32 ? NOFFSETS32 : NOFFSETS64)
 187
 188 /*
 189  * Look through the program headers of an executable image, searching
 190  * for a PT_NOTE section of type NT_PRPSINFO, with a name "CORE" or
 191  * "FreeBSD"; if one is found, try looking in various places in its
 192  * contents for a 16-character string containing only printable
 193  * characters - if found, that string should be the name of the program
 194  * that dropped core.  Note: right after that 16-character string is,
 195  * at least in SunOS 5.x (and possibly other SVR4-flavored systems) and
 196  * Linux, a longer string (80 characters, in 5.x, probably other
 197  * SVR4-flavored systems, and Linux) containing the start of the
 198  * command line for that program.
 199  *
 200  * The signal number probably appears in a section of type NT_PRSTATUS,
 201  * but that's also rather OS-dependent, in ways that are harder to
 202  * dissect with heuristics, so I'm not bothering with the signal number.
 203  * (I suppose the signal number could be of interest in situations where
 204  * you don't have the binary of the program that dropped core; if you
 205  * *do* have that binary, the debugger will probably tell you what
 206  * signal it was.)
 207  */
 208
 209 #define OS_STYLE_SVR4           0
 210 #define OS_STYLE_FREEBSD        1
 211 #define OS_STYLE_NETBSD         2
 212
 213 private const char *os_style_names[] = {
 214         "SVR4",
 215         "FreeBSD",
 216         "NetBSD",
 217 };
 218
 219 private int
 220 dophn_core(struct magic_set *ms, int class, int swap, int fd, off_t off,
 221     int num, size_t size)
 222 {
 223         Elf32_Phdr ph32;
 224         Elf64_Phdr ph64;
 225         size_t offset;
 226         unsigned char nbuf[BUFSIZ];
 227         ssize_t bufsize;
 228
 229         if (size != ph_size) {
 230                 if (file_printf(ms, ", corrupted program header size") == -1)
 231                         return -1;
 232                 return 0;
 233         }
 234         /*
 235          * Loop through all the program headers.
 236          */
 237         for ( ; num; num--) {
 238                 if (lseek(fd, off, SEEK_SET) == (off_t)-1) {
 239                         file_badseek(ms);
 240                         return -1;
 241                 }
 242                 if (read(fd, ph_addr, ph_size) == -1) {
 243                         file_badread(ms);
 244                         return -1;
 245                 }
 246                 off += size;
 247                 if (ph_type != PT_NOTE)
 248                         continue;
 249
 250                 /*
 251                  * This is a PT_NOTE section; loop through all the notes
 252                  * in the section.
 253                  */
 254                 if (lseek(fd, (off_t) ph_offset, SEEK_SET) == (off_t)-1) {
 255                         file_badseek(ms);
 256                         return -1;
 257                 }
 258                 bufsize = read(fd, nbuf,
 259                     ((ph_filesz < sizeof(nbuf)) ? ph_filesz : sizeof(nbuf)));
 260                 if (bufsize == -1) {
 261                         file_badread(ms);
 262                         return -1;
 263                 }
 264                 offset = 0;
 265                 for (;;) {
 266                         if (offset >= (size_t)bufsize)
 267                                 break;
 268                         offset = donote(ms, nbuf, offset, (size_t)bufsize,
 269                             class, swap, 4);
 270                         if (offset == 0)
 271                                 break;
 272
 273                 }
 274         }
 275         return 0;
 276 }
 277 #endif
 278
 279 private size_t
 280 donote(struct magic_set *ms, unsigned char *nbuf, size_t offset, size_t size,
 281     int class, int swap, size_t align)
 282 {
 283         Elf32_Nhdr nh32;
 284         Elf64_Nhdr nh64;
 285         size_t noff, doff;
 286 #ifdef ELFCORE
 287         int os_style = -1;
 288 #endif
 289         uint32_t namesz, descsz;
 290
 291         if (class == ELFCLASS32)
 292                 memcpy(&nh32, &nbuf[offset], sizeof(nh32));
 293         else
 294                 memcpy(&nh64, &nbuf[offset], sizeof(nh64));
 295         offset += nh_size;
 296
 297         namesz = nh_namesz;
 298         descsz = nh_descsz;
 299         if ((namesz == 0) && (descsz == 0)) {
 300                 /*
 301                  * We're out of note headers.
 302                  */
 303                 return offset;
 304         }
 305
 306         if (namesz & 0x80000000) {
 307             (void)file_printf(ms, ", bad note name size 0x%lx",
 308                 (unsigned long)namesz);
 309             return offset;
 310         }
 311
 312         if (descsz & 0x80000000) {
 313             (void)file_printf(ms, ", bad note description size 0x%lx",
 314                 (unsigned long)descsz);
 315             return offset;
 316         }
 317
 318
 319         noff = offset;
 320         doff = ELF_ALIGN(offset + namesz);
 321
 322         if (offset + namesz > size) {
 323                 /*
 324                  * We're past the end of the buffer.
 325                  */
 326                 return doff;
 327         }
 328
 329         offset = ELF_ALIGN(doff + descsz);
 330         if (doff + descsz > size) {
 331                 return offset;
 332         }
 333
 334         if (namesz == 4 && strcmp((char *)&nbuf[noff], "GNU") == 0 &&
 335             nh_type == NT_GNU_VERSION && descsz == 16) {
 336                 uint32_t desc[4];
 337                 (void)memcpy(desc, &nbuf[doff], sizeof(desc));
 338
 339                 if (file_printf(ms, ", for GNU/") == -1)
 340                         return size;
 341                 switch (getu32(swap, desc[0])) {
 342                 case GNU_OS_LINUX:
 343                         if (file_printf(ms, "Linux") == -1)
 344                                 return size;
 345                         break;
 346                 case GNU_OS_HURD:
 347                         if (file_printf(ms, "Hurd") == -1)
 348                                 return size;
 349                         break;
 350                 case GNU_OS_SOLARIS:
 351                         if (file_printf(ms, "Solaris") == -1)
 352                                 return size;
 353                         break;
 354                 default:
 355                         if (file_printf(ms, "<unknown>") == -1)
 356                                 return size;
 357                 }
 358                 if (file_printf(ms, " %d.%d.%d", getu32(swap, desc[1]),
 359                     getu32(swap, desc[2]), getu32(swap, desc[3])) == -1)
 360                         return size;
 361                 return size;
 362         }
 363
 364         if (namesz == 7 && strcmp((char *)&nbuf[noff], "NetBSD") == 0 &&
 365             nh_type == NT_NETBSD_VERSION && descsz == 4) {
 366                 uint32_t desc;
 367                 (void)memcpy(&desc, &nbuf[doff], sizeof(desc));
 368                 desc = getu32(swap, desc);
 369
 370                 if (file_printf(ms, ", for NetBSD") == -1)
 371                         return size;
 372                 /*
 373                  * The version number used to be stuck as 199905, and was thus
 374                  * basically content-free.  Newer versions of NetBSD have fixed
 375                  * this and now use the encoding of __NetBSD_Version__:
 376                  *
 377                  *      MMmmrrpp00
 378                  *
 379                  * M = major version
 380                  * m = minor version
 381                  * r = release ["",A-Z,Z[A-Z] but numeric]
 382                  * p = patchlevel
 383                  */
 384                 if (desc > 100000000U) {
 385                         u_int ver_patch = (desc / 100) % 100;
 386                         u_int ver_rel = (desc / 10000) % 100;
 387                         u_int ver_min = (desc / 1000000) % 100;
 388                         u_int ver_maj = desc / 100000000;
 389
 390                         if (file_printf(ms, " %u.%u", ver_maj, ver_min) == -1)
 391                                 return size;
 392                         if (ver_rel == 0 && ver_patch != 0) {
 393                                 if (file_printf(ms, ".%u", ver_patch) == -1)
 394                                         return size;
 395                         } else if (ver_rel != 0) {
 396                                 while (ver_rel > 26) {
 397                                         file_printf(ms, "Z");
 398                                         ver_rel -= 26;
 399                                 }
 400                                 file_printf(ms, "%c", 'A' + ver_rel - 1);
 401                         }
 402                 }
 403                 return size;
 404         }
 405
 406         if (namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0 &&
 407             nh_type == NT_FREEBSD_VERSION && descsz == 4) {
 408                 uint32_t desc;
 409                 (void)memcpy(&desc, &nbuf[doff], sizeof(desc));
 410                 desc = getu32(swap, desc);
 411                 if (file_printf(ms, ", for FreeBSD") == -1)
 412                         return size;
 413
 414                 /*
 415                  * Contents is __FreeBSD_version, whose relation to OS
 416                  * versions is defined by a huge table in the Porter's
 417                  * Handbook.  This is the general scheme:
 418                  *
 419                  * Releases:
 420                  *      Mmp000 (before 4.10)
 421                  *      Mmi0p0 (before 5.0)
 422                  *      Mmm0p0
 423                  *
 424                  * Development branches:
 425                  *      Mmpxxx (before 4.6)
 426                  *      Mmp1xx (before 4.10)
 427                  *      Mmi1xx (before 5.0)
 428                  *      M000xx (pre-M.0)
 429                  *      Mmm1xx
 430                  *
 431                  * M = major version
 432                  * m = minor version
 433                  * i = minor version increment (491000 -> 4.10)
 434                  * p = patchlevel
 435                  * x = revision
 436                  *
 437                  * The first release of FreeBSD to use ELF by default
 438                  * was version 3.0.
 439                  */
 440                 if (desc == 460002) {
 441                         if (file_printf(ms, " 4.6.2") == -1)
 442                                 return size;
 443                 } else if (desc < 460100) {
 444                         if (file_printf(ms, " %d.%d", desc / 100000,
 445                             desc / 10000 % 10) == -1)
 446                                 return size;
 447                         if (desc / 1000 % 10 > 0)
 448                                 if (file_printf(ms, ".%d", desc / 1000 % 10)
 449                                     == -1)
 450                                         return size;
 451                         if ((desc % 1000 > 0) || (desc % 100000 == 0))
 452                                 if (file_printf(ms, " (%d)", desc) == -1)
 453                                         return size;
 454                 } else if (desc < 500000) {
 455                         if (file_printf(ms, " %d.%d", desc / 100000,
 456                             desc / 10000 % 10 + desc / 1000 % 10) == -1)
 457                                 return size;
 458                         if (desc / 100 % 10 > 0) {
 459                                 if (file_printf(ms, " (%d)", desc) == -1)
 460                                         return size;
 461                         } else if (desc / 10 % 10 > 0) {
 462                                 if (file_printf(ms, ".%d", desc / 10 % 10)
 463                                     == -1)
 464                                         return size;
 465                         }
 466                 } else {
 467                         if (file_printf(ms, " %d.%d", desc / 100000,
 468                             desc / 1000 % 100) == -1)
 469                                 return size;
 470                         if ((desc / 100 % 10 > 0) ||
 471                             (desc % 100000 / 100 == 0)) {
 472                                 if (file_printf(ms, " (%d)", desc) == -1)
 473                                         return size;
 474                         } else if (desc / 10 % 10 > 0) {
 475                                 if (file_printf(ms, ".%d", desc / 10 % 10)
 476                                     == -1)
 477                                         return size;
 478                         }
 479                 }
 480                 return size;
 481         }
 482
 483         if (namesz == 8 && strcmp((char *)&nbuf[noff], "OpenBSD") == 0 &&
 484             nh_type == NT_OPENBSD_VERSION && descsz == 4) {
 485                 if (file_printf(ms, ", for OpenBSD") == -1)
 486                         return size;
 487                 /* Content of note is always 0 */
 488                 return size;
 489         }
 490
 491         if (namesz == 10 && strcmp((char *)&nbuf[noff], "DragonFly") == 0 &&
 492             nh_type == NT_DRAGONFLY_VERSION && descsz == 4) {
 493                 if (file_printf(ms, ", for DragonFly") == -1)
 494                         return size;
 495                 uint32_t desc;
 496                 (void)memcpy(&desc, &nbuf[doff], sizeof(desc));
 497                 desc = getu32(swap, desc);
 498                 if (file_printf(ms, " %d.%d.%d", desc / 100000,
 499                     desc / 10000 % 10, desc % 10000) == -1)
 500                         return size;
 501                 return size;
 502         }
 503
 504         /*
 505          * Sigh.  The 2.0.36 kernel in Debian 2.1, at
 506          * least, doesn't correctly implement name
 507          * sections, in core dumps, as specified by
 508          * the "Program Linking" section of "UNIX(R) System
 509          * V Release 4 Programmer's Guide: ANSI C and
 510          * Programming Support Tools", because my copy
 511          * clearly says "The first 'namesz' bytes in 'name'
 512          * contain a *null-terminated* [emphasis mine]
 513          * character representation of the entry's owner
 514          * or originator", but the 2.0.36 kernel code
 515          * doesn't include the terminating null in the
 516          * name....
 517          */
 518         if ((namesz == 4 && strncmp((char *)&nbuf[noff], "CORE", 4) == 0) ||
 519             (namesz == 5 && strcmp((char *)&nbuf[noff], "CORE") == 0)) {
 520                 os_style = OS_STYLE_SVR4;
 521         }
 522
 523         if ((namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0)) {
 524                 os_style = OS_STYLE_FREEBSD;
 525         }
 526
 527         if ((namesz >= 11 && strncmp((char *)&nbuf[noff], "NetBSD-CORE", 11)
 528             == 0)) {
 529                 os_style = OS_STYLE_NETBSD;
 530         }
 531
 532 #ifdef ELFCORE
 533         if (os_style != -1)
 534                 if (file_printf(ms, ", %s-style", os_style_names[os_style]) == -1)
 535                         return size;
 536
 537         if (os_style == OS_STYLE_NETBSD && nh_type == NT_NETBSD_CORE_PROCINFO) {
 538                 uint32_t signo;
 539                 /*
 540                  * Extract the program name.  It is at
 541                  * offset 0x7c, and is up to 32-bytes,
 542                  * including the terminating NUL.
 543                  */
 544                 if (file_printf(ms, ", from '%.31s'", &nbuf[doff + 0x7c]) == -1)
 545                         return size;
 546
 547                 /*
 548                  * Extract the signal number.  It is at
 549                  * offset 0x08.
 550                  */
 551                 memcpy(&signo, &nbuf[doff + 0x08],
 552                     sizeof(signo));
 553                 if (file_printf(ms, " (signal %u)", getu32(swap, signo)) == -1)
 554                         return size;
 555                 return size;
 556         } else if (os_style != OS_STYLE_NETBSD && nh_type == NT_PRPSINFO) {
 557                 size_t i, j;
 558                 unsigned char c;
 559                 /*
 560                  * Extract the program name.  We assume
 561                  * it to be 16 characters (that's what it
 562                  * is in SunOS 5.x and Linux).
 563                  *
 564                  * Unfortunately, it's at a different offset
 565                  * in varous OSes, so try multiple offsets.
 566                  * If the characters aren't all printable,
 567                  * reject it.
 568                  */
 569                 for (i = 0; i < NOFFSETS; i++) {
 570                         size_t reloffset = prpsoffsets(i);
 571                         size_t noffset = doff + reloffset;
 572                         for (j = 0; j < 16; j++, noffset++, reloffset++) {
 573                                 /*
 574                                  * Make sure we're not past
 575                                  * the end of the buffer; if
 576                                  * we are, just give up.
 577                                  */
 578                                 if (noffset >= size)
 579                                         goto tryanother;
 580
 581                                 /*
 582                                  * Make sure we're not past
 583                                  * the end of the contents;
 584                                  * if we are, this obviously
 585                                  * isn't the right offset.
 586                                  */
 587                                 if (reloffset >= descsz)
 588                                         goto tryanother;
 589
 590                                 c = nbuf[noffset];
 591                                 if (c == '\0') {
 592                                         /*
 593                                          * A '\0' at the
 594                                          * beginning is
 595                                          * obviously wrong.
 596                                          * Any other '\0'
 597                                          * means we're done.
 598                                          */
 599                                         if (j == 0)
 600                                                 goto tryanother;
 601                                         else
 602                                                 break;
 603                                 } else {
 604                                         /*
 605                                          * A nonprintable
 606                                          * character is also
 607                                          * wrong.
 608                                          */
 609 #define isquote(c) (strchr("'\"`", (c)) != NULL)
 610                                         if (!isprint(c) || isquote(c))
 611                                                 goto tryanother;
 612                                 }
 613                         }
 614
 615                         /*
 616                          * Well, that worked.
 617                          */
 618                         if (file_printf(ms, ", from '%.16s'",
 619                             &nbuf[doff + prpsoffsets(i)]) == -1)
 620                                 return size;
 621                         return size;
 622
 623                 tryanother:
 624                         ;
 625                 }
 626                 return offset;
 627         }
 628 #endif
 629         return offset;
 630 }
 631
 632 private int
 633 doshn(struct magic_set *ms, int class, int swap, int fd, off_t off, int num,
 634     size_t size)
 635 {
 636         Elf32_Shdr sh32;
 637         Elf64_Shdr sh64;
 638
 639         if (size != sh_size) {
 640                 if (file_printf(ms, ", corrupted section header size") == -1)
 641                         return -1;
 642                 return 0;
 643         }
 644
 645         if (lseek(fd, off, SEEK_SET) == (off_t)-1) {
 646                 file_badseek(ms);
 647                 return -1;
 648         }
 649
 650         for ( ; num; num--) {
 651                 if (read(fd, sh_addr, sh_size) == -1) {
 652                         file_badread(ms);
 653                         return -1;
 654                 }
 655                 if (shs_type == SHT_SYMTAB /* || shs_type == SHT_DYNSYM */) {
 656                         if (file_printf(ms, ", not stripped") == -1)
 657                                 return -1;
 658                         return 0;
 659                 }
 660         }
 661         if (file_printf(ms, ", stripped") == -1)
 662                 return -1;
 663         return 0;
 664 }
 665
 666 /*
 667  * Look through the program headers of an executable image, searching
 668  * for a PT_INTERP section; if one is found, it's dynamically linked,
 669  * otherwise it's statically linked.
 670  */
 671 private int
 672 dophn_exec(struct magic_set *ms, int class, int swap, int fd, off_t off,
 673     int num, size_t size)
 674 {
 675         Elf32_Phdr ph32;
 676         Elf64_Phdr ph64;
 677         const char *linking_style = "statically";
 678         const char *shared_libraries = "";
 679         unsigned char nbuf[BUFSIZ];
 680         int bufsize;
 681         size_t offset, align;
 682         off_t savedoffset;
 683
 684         if (size != ph_size) {
 685                 if (file_printf(ms, ", corrupted program header size") == -1)
 686                     return -1;
 687                 return 0;
 688         }
 689         if (lseek(fd, off, SEEK_SET) == (off_t)-1) {
 690                 file_badseek(ms);
 691                 return -1;
 692         }
 693
 694         for ( ; num; num--) {
 695                 if (read(fd, ph_addr, ph_size) == -1) {
 696                         file_badread(ms);
 697                         return -1;
 698                 }
 699                 if ((savedoffset = lseek(fd, (off_t)0, SEEK_CUR)) == (off_t)-1) {
 700                         file_badseek(ms);
 701                         return -1;
 702                 }
 703
 704                 switch (ph_type) {
 705                 case PT_DYNAMIC:
 706                         linking_style = "dynamically";
 707                         break;
 708                 case PT_INTERP:
 709                         shared_libraries = " (uses shared libs)";
 710                         break;
 711                 case PT_NOTE:
 712                         if ((align = ph_align) & 0x80000000) {
 713                                 if (file_printf(ms,
 714                                     ", invalid note alignment 0x%lx",
 715                                     (unsigned long)align) == -1)
 716                                         return -1;
 717                                 align = 4;
 718                         }
 719                         /*
 720                          * This is a PT_NOTE section; loop through all the notes
 721                          * in the section.
 722                          */
 723                         if (lseek(fd, (off_t) ph_offset, SEEK_SET)
 724                             == (off_t)-1) {
 725                                 file_badseek(ms);
 726                                 return -1;
 727                         }
 728                         bufsize = read(fd, nbuf, ((ph_filesz < sizeof(nbuf)) ?
 729                             ph_filesz : sizeof(nbuf)));
 730                         if (bufsize == -1) {
 731                                 file_badread(ms);
 732                                 return -1;
 733                         }
 734                         offset = 0;
 735                         for (;;) {
 736                                 if (offset >= (size_t)bufsize)
 737                                         break;
 738                                 offset = donote(ms, nbuf, offset,
 739                                     (size_t)bufsize, class, swap, align);
 740                                 if (offset == 0)
 741                                         break;
 742                         }
 743                         if (lseek(fd, savedoffset, SEEK_SET) == (off_t)-1) {
 744                                 file_badseek(ms);
 745                                 return -1;
 746                         }
 747                         break;
 748                 }
 749         }
 750         if (file_printf(ms, ", %s linked%s", linking_style, shared_libraries)
 751             == -1)
 752             return -1;
 753         return 0;
 754 }
 755
 756
 757 protected int
 758 file_tryelf(struct magic_set *ms, int fd, const unsigned char *buf,
 759     size_t nbytes)
 760 {
 761         union {
 762                 int32_t l;
 763                 char c[sizeof (int32_t)];
 764         } u;
 765         int class;
 766         int swap;
 767
 768         /*
 769          * If we cannot seek, it must be a pipe, socket or fifo.
 770          */
 771         if((lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) && (errno == ESPIPE))
 772                 fd = file_pipe2file(ms, fd, buf, nbytes);
 773
 774         /*
 775          * ELF executables have multiple section headers in arbitrary
 776          * file locations and thus file(1) cannot determine it from easily.
 777          * Instead we traverse thru all section headers until a symbol table
 778          * one is found or else the binary is stripped.
 779          */
 780         if (buf[EI_MAG0] != ELFMAG0
 781             || (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
 782             || buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
 783             return 0;
 784
 785
 786         class = buf[4];
 787
 788         if (class == ELFCLASS32) {
 789                 Elf32_Ehdr elfhdr;
 790                 if (nbytes <= sizeof (Elf32_Ehdr))
 791                         return 0;
 792
 793
 794                 u.l = 1;
 795                 (void) memcpy(&elfhdr, buf, sizeof elfhdr);
 796                 swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
 797
 798                 if (getu16(swap, elfhdr.e_type) == ET_CORE) {
 799 #ifdef ELFCORE
 800                         if (dophn_core(ms, class, swap, fd,
 801                             (off_t)getu32(swap, elfhdr.e_phoff),
 802                             getu16(swap, elfhdr.e_phnum),
 803                             (size_t)getu16(swap, elfhdr.e_phentsize)) == -1)
 804                                 return -1;
 805 #else
 806                         ;
 807 #endif
 808                 } else {
 809                         if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
 810                                 if (dophn_exec(ms, class, swap,
 811                                     fd, (off_t)getu32(swap, elfhdr.e_phoff),
 812                                     getu16(swap, elfhdr.e_phnum),
 813                                     (size_t)getu16(swap, elfhdr.e_phentsize))
 814                                     == -1)
 815                                         return -1;
 816                         }
 817                         if (doshn(ms, class, swap, fd,
 818                             (off_t)getu32(swap, elfhdr.e_shoff),
 819                             getu16(swap, elfhdr.e_shnum),
 820                             (size_t)getu16(swap, elfhdr.e_shentsize)) == -1)
 821                                 return -1;
 822                 }
 823                 return 1;
 824         }
 825
 826         if (class == ELFCLASS64) {
 827                 Elf64_Ehdr elfhdr;
 828                 if (nbytes <= sizeof (Elf64_Ehdr))
 829                         return 0;
 830
 831
 832                 u.l = 1;
 833                 (void) memcpy(&elfhdr, buf, sizeof elfhdr);
 834                 swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
 835
 836                 if (getu16(swap, elfhdr.e_type) == ET_CORE) {
 837 #ifdef ELFCORE
 838                         if (dophn_core(ms, class, swap, fd,
 839 #ifdef USE_ARRAY_FOR_64BIT_TYPES
 840                             (off_t)getu32(swap, elfhdr.e_phoff[1]),
 841 #else
 842                             (off_t)getu64(swap, elfhdr.e_phoff),
 843 #endif
 844                             getu16(swap, elfhdr.e_phnum),
 845                             (size_t)getu16(swap, elfhdr.e_phentsize)) == -1)
 846                                 return -1;
 847 #else
 848                         ;
 849 #endif
 850                 } else {
 851                         if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
 852                                 if (dophn_exec(ms, class, swap, fd,
 853 #ifdef USE_ARRAY_FOR_64BIT_TYPES
 854                                     (off_t)getu32(swap, elfhdr.e_phoff[1]),
 855 #else
 856                                     (off_t)getu64(swap, elfhdr.e_phoff),
 857 #endif
 858                                     getu16(swap, elfhdr.e_phnum),
 859                                     (size_t)getu16(swap, elfhdr.e_phentsize))
 860                                     == -1)
 861                                         return -1;
 862                         }
 863                         if (doshn(ms, class, swap, fd,
 864 #ifdef USE_ARRAY_FOR_64BIT_TYPES
 865                             (off_t)getu32(swap, elfhdr.e_shoff[1]),
 866 #else
 867                             (off_t)getu64(swap, elfhdr.e_shoff),
 868 #endif
 869                             getu16(swap, elfhdr.e_shnum),
 870                             (size_t)getu16(swap, elfhdr.e_shentsize)) == -1)
 871                                 return -1;
 872                 }
 873                 return 1;
 874         }
 875         return 0;
 876 }
 877 #endif