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 1.45 2004/11/24 17:38:24 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        120,             /* SunOS 5.x, 64-bit */
 180 };
 181
 182 #define NOFFSETS32      (sizeof prpsoffsets32 / sizeof prpsoffsets32[0])
 183 #define NOFFSETS64      (sizeof prpsoffsets64 / sizeof prpsoffsets64[0])
 184
 185 #define NOFFSETS        (class == ELFCLASS32 ? NOFFSETS32 : NOFFSETS64)
 186
 187 /*
 188  * Look through the program headers of an executable image, searching
 189  * for a PT_NOTE section of type NT_PRPSINFO, with a name "CORE" or
 190  * "FreeBSD"; if one is found, try looking in various places in its
 191  * contents for a 16-character string containing only printable
 192  * characters - if found, that string should be the name of the program
 193  * that dropped core.  Note: right after that 16-character string is,
 194  * at least in SunOS 5.x (and possibly other SVR4-flavored systems) and
 195  * Linux, a longer string (80 characters, in 5.x, probably other
 196  * SVR4-flavored systems, and Linux) containing the start of the
 197  * command line for that program.
 198  *
 199  * The signal number probably appears in a section of type NT_PRSTATUS,
 200  * but that's also rather OS-dependent, in ways that are harder to
 201  * dissect with heuristics, so I'm not bothering with the signal number.
 202  * (I suppose the signal number could be of interest in situations where
 203  * you don't have the binary of the program that dropped core; if you
 204  * *do* have that binary, the debugger will probably tell you what
 205  * signal it was.)
 206  */
 207
 208 #define OS_STYLE_SVR4           0
 209 #define OS_STYLE_FREEBSD        1
 210 #define OS_STYLE_NETBSD         2
 211
 212 private const char *os_style_names[] = {
 213         "SVR4",
 214         "FreeBSD",
 215         "NetBSD",
 216 };
 217
 218 private int
 219 dophn_core(struct magic_set *ms, int class, int swap, int fd, off_t off,
 220     int num, size_t size)
 221 {
 222         Elf32_Phdr ph32;
 223         Elf64_Phdr ph64;
 224         size_t offset;
 225         unsigned char nbuf[BUFSIZ];
 226         ssize_t bufsize;
 227
 228         if (size != ph_size) {
 229                 if (file_printf(ms, ", corrupted program header size") == -1)
 230                         return -1;
 231                 return 0;
 232         }
 233         /*
 234          * Loop through all the program headers.
 235          */
 236         for ( ; num; num--) {
 237                 if (lseek(fd, off, SEEK_SET) == (off_t)-1) {
 238                         file_badseek(ms);
 239                         return -1;
 240                 }
 241                 if (read(fd, ph_addr, ph_size) == -1) {
 242                         file_badread(ms);
 243                         return -1;
 244                 }
 245                 off += size;
 246                 if (ph_type != PT_NOTE)
 247                         continue;
 248
 249                 /*
 250                  * This is a PT_NOTE section; loop through all the notes
 251                  * in the section.
 252                  */
 253                 if (lseek(fd, (off_t) ph_offset, SEEK_SET) == (off_t)-1) {
 254                         file_badseek(ms);
 255                         return -1;
 256                 }
 257                 bufsize = read(fd, nbuf,
 258                     ((ph_filesz < sizeof(nbuf)) ? ph_filesz : sizeof(nbuf)));
 259                 if (bufsize == -1) {
 260                         file_badread(ms);
 261                         return -1;
 262                 }
 263                 offset = 0;
 264                 for (;;) {
 265                         if (offset >= (size_t)bufsize)
 266                                 break;
 267                         offset = donote(ms, nbuf, offset, (size_t)bufsize,
 268                             class, swap, 4);
 269                         if (offset == 0)
 270                                 break;
 271
 272                 }
 273         }
 274         return 0;
 275 }
 276 #endif
 277
 278 private size_t
 279 donote(struct magic_set *ms, unsigned char *nbuf, size_t offset, size_t size,
 280     int class, int swap, size_t align)
 281 {
 282         Elf32_Nhdr nh32;
 283         Elf64_Nhdr nh64;
 284         size_t noff, doff;
 285 #ifdef ELFCORE
 286         int os_style = -1;
 287 #endif
 288         uint32_t namesz, descsz;
 289
 290         if (class == ELFCLASS32)
 291                 memcpy(&nh32, &nbuf[offset], sizeof(nh32));
 292         else
 293                 memcpy(&nh64, &nbuf[offset], sizeof(nh64));
 294         offset += nh_size;
 295
 296         namesz = nh_namesz;
 297         descsz = nh_descsz;
 298         if ((namesz == 0) && (descsz == 0)) {
 299                 /*
 300                  * We're out of note headers.
 301                  */
 302                 return offset;
 303         }
 304
 305         if (namesz & 0x80000000) {
 306             (void)file_printf(ms, ", bad note name size 0x%lx",
 307                 (unsigned long)namesz);
 308             return offset;
 309         }
 310
 311         if (descsz & 0x80000000) {
 312             (void)file_printf(ms, ", bad note description size 0x%lx",
 313                 (unsigned long)descsz);
 314             return offset;
 315         }
 316
 317
 318         noff = offset;
 319         doff = ELF_ALIGN(offset + namesz);
 320
 321         if (offset + namesz > size) {
 322                 /*
 323                  * We're past the end of the buffer.
 324                  */
 325                 return doff;
 326         }
 327
 328         offset = ELF_ALIGN(doff + descsz);
 329         if (doff + descsz > size) {
 330                 return offset;
 331         }
 332
 333         if (namesz == 4 && strcmp((char *)&nbuf[noff], "GNU") == 0 &&
 334             nh_type == NT_GNU_VERSION && descsz == 16) {
 335                 uint32_t desc[4];
 336                 (void)memcpy(desc, &nbuf[doff], sizeof(desc));
 337
 338                 if (file_printf(ms, ", for GNU/") == -1)
 339                         return size;
 340                 switch (getu32(swap, desc[0])) {
 341                 case GNU_OS_LINUX:
 342                         if (file_printf(ms, "Linux") == -1)
 343                                 return size;
 344                         break;
 345                 case GNU_OS_HURD:
 346                         if (file_printf(ms, "Hurd") == -1)
 347                                 return size;
 348                         break;
 349                 case GNU_OS_SOLARIS:
 350                         if (file_printf(ms, "Solaris") == -1)
 351                                 return size;
 352                         break;
 353                 default:
 354                         if (file_printf(ms, "<unknown>") == -1)
 355                                 return size;
 356                 }
 357                 if (file_printf(ms, " %d.%d.%d", getu32(swap, desc[1]),
 358                     getu32(swap, desc[2]), getu32(swap, desc[3])) == -1)
 359                         return size;
 360                 return size;
 361         }
 362
 363         if (namesz == 7 && strcmp((char *)&nbuf[noff], "NetBSD") == 0 &&
 364             nh_type == NT_NETBSD_VERSION && descsz == 4) {
 365                 uint32_t desc;
 366                 (void)memcpy(&desc, &nbuf[doff], sizeof(desc));
 367                 desc = getu32(swap, desc);
 368
 369                 if (file_printf(ms, ", for NetBSD") == -1)
 370                         return size;
 371                 /*
 372                  * The version number used to be stuck as 199905, and was thus
 373                  * basically content-free.  Newer versions of NetBSD have fixed
 374                  * this and now use the encoding of __NetBSD_Version__:
 375                  *
 376                  *      MMmmrrpp00
 377                  *
 378                  * M = major version
 379                  * m = minor version
 380                  * r = release ["",A-Z,Z[A-Z] but numeric]
 381                  * p = patchlevel
 382                  */
 383                 if (desc > 100000000U) {
 384                         u_int ver_patch = (desc / 100) % 100;
 385                         u_int ver_rel = (desc / 10000) % 100;
 386                         u_int ver_min = (desc / 1000000) % 100;
 387                         u_int ver_maj = desc / 100000000;
 388
 389                         if (file_printf(ms, " %u.%u", ver_maj, ver_min) == -1)
 390                                 return size;
 391                         if (ver_rel == 0 && ver_patch != 0) {
 392                                 if (file_printf(ms, ".%u", ver_patch) == -1)
 393                                         return size;
 394                         } else if (ver_rel != 0) {
 395                                 while (ver_rel > 26) {
 396                                         file_printf(ms, "Z");
 397                                         ver_rel -= 26;
 398                                 }
 399                                 file_printf(ms, "%c", 'A' + ver_rel - 1);
 400                         }
 401                 }
 402                 return size;
 403         }
 404
 405         if (namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0 &&
 406             nh_type == NT_FREEBSD_VERSION && descsz == 4) {
 407                 uint32_t desc;
 408                 (void)memcpy(&desc, &nbuf[doff], sizeof(desc));
 409                 desc = getu32(swap, desc);
 410                 if (file_printf(ms, ", for FreeBSD") == -1)
 411                         return size;
 412
 413                 /*
 414                  * Contents is __FreeBSD_version, whose relation to OS
 415                  * versions is defined by a huge table in the Porter's
 416                  * Handbook.  This is the general scheme:
 417                  *
 418                  * Releases:
 419                  *      Mmp000 (before 4.10)
 420                  *      Mmi0p0 (before 5.0)
 421                  *      Mmm0p0
 422                  *
 423                  * Development branches:
 424                  *      Mmpxxx (before 4.6)
 425                  *      Mmp1xx (before 4.10)
 426                  *      Mmi1xx (before 5.0)
 427                  *      M000xx (pre-M.0)
 428                  *      Mmm1xx
 429                  *
 430                  * M = major version
 431                  * m = minor version
 432                  * i = minor version increment (491000 -> 4.10)
 433                  * p = patchlevel
 434                  * x = revision
 435                  *
 436                  * The first release of FreeBSD to use ELF by default
 437                  * was version 3.0.
 438                  */
 439                 if (desc == 460002) {
 440                         if (file_printf(ms, " 4.6.2") == -1)
 441                                 return size;
 442                 } else if (desc < 460100) {
 443                         if (file_printf(ms, " %d.%d", desc / 100000,
 444                             desc / 10000 % 10) == -1)
 445                                 return size;
 446                         if (desc / 1000 % 10 > 0)
 447                                 if (file_printf(ms, ".%d", desc / 1000 % 10)
 448                                     == -1)
 449                                         return size;
 450                         if ((desc % 1000 > 0) || (desc % 100000 == 0))
 451                                 if (file_printf(ms, " (%d)", desc) == -1)
 452                                         return size;
 453                 } else if (desc < 500000) {
 454                         if (file_printf(ms, " %d.%d", desc / 100000,
 455                             desc / 10000 % 10 + desc / 1000 % 10) == -1)
 456                                 return size;
 457                         if (desc / 100 % 10 > 0) {
 458                                 if (file_printf(ms, " (%d)", desc) == -1)
 459                                         return size;
 460                         } else if (desc / 10 % 10 > 0) {
 461                                 if (file_printf(ms, ".%d", desc / 10 % 10)
 462                                     == -1)
 463                                         return size;
 464                         }
 465                 } else {
 466                         if (file_printf(ms, " %d.%d", desc / 100000,
 467                             desc / 1000 % 100) == -1)
 468                                 return size;
 469                         if ((desc / 100 % 10 > 0) ||
 470                             (desc % 100000 / 100 == 0)) {
 471                                 if (file_printf(ms, " (%d)", desc) == -1)
 472                                         return size;
 473                         } else if (desc / 10 % 10 > 0) {
 474                                 if (file_printf(ms, ".%d", desc / 10 % 10)
 475                                     == -1)
 476                                         return size;
 477                         }
 478                 }
 479                 return size;
 480         }
 481
 482         if (namesz == 8 && strcmp((char *)&nbuf[noff], "OpenBSD") == 0 &&
 483             nh_type == NT_OPENBSD_VERSION && descsz == 4) {
 484                 if (file_printf(ms, ", for OpenBSD") == -1)
 485                         return size;
 486                 /* Content of note is always 0 */
 487                 return size;
 488         }
 489
 490         /*
 491          * Sigh.  The 2.0.36 kernel in Debian 2.1, at
 492          * least, doesn't correctly implement name
 493          * sections, in core dumps, as specified by
 494          * the "Program Linking" section of "UNIX(R) System
 495          * V Release 4 Programmer's Guide: ANSI C and
 496          * Programming Support Tools", because my copy
 497          * clearly says "The first 'namesz' bytes in 'name'
 498          * contain a *null-terminated* [emphasis mine]
 499          * character representation of the entry's owner
 500          * or originator", but the 2.0.36 kernel code
 501          * doesn't include the terminating null in the
 502          * name....
 503          */
 504         if ((namesz == 4 && strncmp((char *)&nbuf[noff], "CORE", 4) == 0) ||
 505             (namesz == 5 && strcmp((char *)&nbuf[noff], "CORE") == 0)) {
 506                 os_style = OS_STYLE_SVR4;
 507         }
 508
 509         if ((namesz == 8 && strcmp((char *)&nbuf[noff], "FreeBSD") == 0)) {
 510                 os_style = OS_STYLE_FREEBSD;
 511         }
 512
 513         if ((namesz >= 11 && strncmp((char *)&nbuf[noff], "NetBSD-CORE", 11)
 514             == 0)) {
 515                 os_style = OS_STYLE_NETBSD;
 516         }
 517
 518 #ifdef ELFCORE
 519         if (os_style != -1)
 520                 if (file_printf(ms, ", %s-style", os_style_names[os_style]) == -1)
 521                         return size;
 522
 523         if (os_style == OS_STYLE_NETBSD && nh_type == NT_NETBSD_CORE_PROCINFO) {
 524                 uint32_t signo;
 525                 /*
 526                  * Extract the program name.  It is at
 527                  * offset 0x7c, and is up to 32-bytes,
 528                  * including the terminating NUL.
 529                  */
 530                 if (file_printf(ms, ", from '%.31s'", &nbuf[doff + 0x7c]) == -1)
 531                         return size;
 532
 533                 /*
 534                  * Extract the signal number.  It is at
 535                  * offset 0x08.
 536                  */
 537                 memcpy(&signo, &nbuf[doff + 0x08],
 538                     sizeof(signo));
 539                 if (file_printf(ms, " (signal %u)", getu32(swap, signo)) == -1)
 540                         return size;
 541                 return size;
 542         } else if (os_style != OS_STYLE_NETBSD && nh_type == NT_PRPSINFO) {
 543                 size_t i, j;
 544                 unsigned char c;
 545                 /*
 546                  * Extract the program name.  We assume
 547                  * it to be 16 characters (that's what it
 548                  * is in SunOS 5.x and Linux).
 549                  *
 550                  * Unfortunately, it's at a different offset
 551                  * in varous OSes, so try multiple offsets.
 552                  * If the characters aren't all printable,
 553                  * reject it.
 554                  */
 555                 for (i = 0; i < NOFFSETS; i++) {
 556                         size_t reloffset = prpsoffsets(i);
 557                         size_t noffset = doff + reloffset;
 558                         for (j = 0; j < 16; j++, noffset++, reloffset++) {
 559                                 /*
 560                                  * Make sure we're not past
 561                                  * the end of the buffer; if
 562                                  * we are, just give up.
 563                                  */
 564                                 if (noffset >= size)
 565                                         goto tryanother;
 566
 567                                 /*
 568                                  * Make sure we're not past
 569                                  * the end of the contents;
 570                                  * if we are, this obviously
 571                                  * isn't the right offset.
 572                                  */
 573                                 if (reloffset >= descsz)
 574                                         goto tryanother;
 575
 576                                 c = nbuf[noffset];
 577                                 if (c == '\0') {
 578                                         /*
 579                                          * A '\0' at the
 580                                          * beginning is
 581                                          * obviously wrong.
 582                                          * Any other '\0'
 583                                          * means we're done.
 584                                          */
 585                                         if (j == 0)
 586                                                 goto tryanother;
 587                                         else
 588                                                 break;
 589                                 } else {
 590                                         /*
 591                                          * A nonprintable
 592                                          * character is also
 593                                          * wrong.
 594                                          */
 595 #define isquote(c) (strchr("'\"`", (c)) != NULL)
 596                                         if (!isprint(c) || isquote(c))
 597                                                 goto tryanother;
 598                                 }
 599                         }
 600
 601                         /*
 602                          * Well, that worked.
 603                          */
 604                         if (file_printf(ms, ", from '%.16s'",
 605                             &nbuf[doff + prpsoffsets(i)]) == -1)
 606                                 return size;
 607                         return size;
 608
 609                 tryanother:
 610                         ;
 611                 }
 612                 return offset;
 613         }
 614 #endif
 615         return offset;
 616 }
 617
 618 private int
 619 doshn(struct magic_set *ms, int class, int swap, int fd, off_t off, int num,
 620     size_t size)
 621 {
 622         Elf32_Shdr sh32;
 623         Elf64_Shdr sh64;
 624
 625         if (size != sh_size) {
 626                 if (file_printf(ms, ", corrupted section header size") == -1)
 627                         return -1;
 628                 return 0;
 629         }
 630
 631         if (lseek(fd, off, SEEK_SET) == (off_t)-1) {
 632                 file_badseek(ms);
 633                 return -1;
 634         }
 635
 636         for ( ; num; num--) {
 637                 if (read(fd, sh_addr, sh_size) == -1) {
 638                         file_badread(ms);
 639                         return -1;
 640                 }
 641                 if (shs_type == SHT_SYMTAB /* || shs_type == SHT_DYNSYM */) {
 642                         if (file_printf(ms, ", not stripped") == -1)
 643                                 return -1;
 644                         return 0;
 645                 }
 646         }
 647         if (file_printf(ms, ", stripped") == -1)
 648                 return -1;
 649         return 0;
 650 }
 651
 652 /*
 653  * Look through the program headers of an executable image, searching
 654  * for a PT_INTERP section; if one is found, it's dynamically linked,
 655  * otherwise it's statically linked.
 656  */
 657 private int
 658 dophn_exec(struct magic_set *ms, int class, int swap, int fd, off_t off,
 659     int num, size_t size)
 660 {
 661         Elf32_Phdr ph32;
 662         Elf64_Phdr ph64;
 663         const char *linking_style = "statically";
 664         const char *shared_libraries = "";
 665         unsigned char nbuf[BUFSIZ];
 666         int bufsize;
 667         size_t offset, align;
 668         off_t savedoffset;
 669
 670         if (size != ph_size) {
 671                 if (file_printf(ms, ", corrupted program header size") == -1)
 672                     return -1;
 673                 return 0;
 674         }
 675         if (lseek(fd, off, SEEK_SET) == (off_t)-1) {
 676                 file_badseek(ms);
 677                 return -1;
 678         }
 679
 680         for ( ; num; num--) {
 681                 if (read(fd, ph_addr, ph_size) == -1) {
 682                         file_badread(ms);
 683                         return -1;
 684                 }
 685                 if ((savedoffset = lseek(fd, (off_t)0, SEEK_CUR)) == (off_t)-1) {
 686                         file_badseek(ms);
 687                         return -1;
 688                 }
 689
 690                 switch (ph_type) {
 691                 case PT_DYNAMIC:
 692                         linking_style = "dynamically";
 693                         break;
 694                 case PT_INTERP:
 695                         shared_libraries = " (uses shared libs)";
 696                         break;
 697                 case PT_NOTE:
 698                         if ((align = ph_align) & 0x80000000) {
 699                                 if (file_printf(ms,
 700                                     ", invalid note alignment 0x%lx",
 701                                     (unsigned long)align) == -1)
 702                                         return -1;
 703                                 align = 4;
 704                         }
 705                         /*
 706                          * This is a PT_NOTE section; loop through all the notes
 707                          * in the section.
 708                          */
 709                         if (lseek(fd, (off_t) ph_offset, SEEK_SET)
 710                             == (off_t)-1) {
 711                                 file_badseek(ms);
 712                                 return -1;
 713                         }
 714                         bufsize = read(fd, nbuf, ((ph_filesz < sizeof(nbuf)) ?
 715                             ph_filesz : sizeof(nbuf)));
 716                         if (bufsize == -1) {
 717                                 file_badread(ms);
 718                                 return -1;
 719                         }
 720                         offset = 0;
 721                         for (;;) {
 722                                 if (offset >= (size_t)bufsize)
 723                                         break;
 724                                 offset = donote(ms, nbuf, offset,
 725                                     (size_t)bufsize, class, swap, align);
 726                                 if (offset == 0)
 727                                         break;
 728                         }
 729                         if (lseek(fd, savedoffset, SEEK_SET) == (off_t)-1) {
 730                                 file_badseek(ms);
 731                                 return -1;
 732                         }
 733                         break;
 734                 }
 735         }
 736         if (file_printf(ms, ", %s linked%s", linking_style, shared_libraries)
 737             == -1)
 738             return -1;
 739         return 0;
 740 }
 741
 742
 743 protected int
 744 file_tryelf(struct magic_set *ms, int fd, const unsigned char *buf,
 745     size_t nbytes)
 746 {
 747         union {
 748                 int32_t l;
 749                 char c[sizeof (int32_t)];
 750         } u;
 751         int class;
 752         int swap;
 753
 754         /*
 755          * If we cannot seek, it must be a pipe, socket or fifo.
 756          */
 757         if((lseek(fd, (off_t)0, SEEK_SET) == (off_t)-1) && (errno == ESPIPE))
 758                 fd = file_pipe2file(ms, fd, buf, nbytes);
 759
 760         /*
 761          * ELF executables have multiple section headers in arbitrary
 762          * file locations and thus file(1) cannot determine it from easily.
 763          * Instead we traverse thru all section headers until a symbol table
 764          * one is found or else the binary is stripped.
 765          */
 766         if (buf[EI_MAG0] != ELFMAG0
 767             || (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
 768             || buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
 769             return 0;
 770
 771
 772         class = buf[4];
 773
 774         if (class == ELFCLASS32) {
 775                 Elf32_Ehdr elfhdr;
 776                 if (nbytes <= sizeof (Elf32_Ehdr))
 777                         return 0;
 778
 779
 780                 u.l = 1;
 781                 (void) memcpy(&elfhdr, buf, sizeof elfhdr);
 782                 swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
 783
 784                 if (getu16(swap, elfhdr.e_type) == ET_CORE) {
 785 #ifdef ELFCORE
 786                         if (dophn_core(ms, class, swap, fd,
 787                             (off_t)getu32(swap, elfhdr.e_phoff),
 788                             getu16(swap, elfhdr.e_phnum),
 789                             (size_t)getu16(swap, elfhdr.e_phentsize)) == -1)
 790                                 return -1;
 791 #else
 792                         ;
 793 #endif
 794                 } else {
 795                         if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
 796                                 if (dophn_exec(ms, class, swap,
 797                                     fd, (off_t)getu32(swap, elfhdr.e_phoff),
 798                                     getu16(swap, elfhdr.e_phnum),
 799                                     (size_t)getu16(swap, elfhdr.e_phentsize))
 800                                     == -1)
 801                                         return -1;
 802                         }
 803                         if (doshn(ms, class, swap, fd,
 804                             (off_t)getu32(swap, elfhdr.e_shoff),
 805                             getu16(swap, elfhdr.e_shnum),
 806                             (size_t)getu16(swap, elfhdr.e_shentsize)) == -1)
 807                                 return -1;
 808                 }
 809                 return 1;
 810         }
 811
 812         if (class == ELFCLASS64) {
 813                 Elf64_Ehdr elfhdr;
 814                 if (nbytes <= sizeof (Elf64_Ehdr))
 815                         return 0;
 816
 817
 818                 u.l = 1;
 819                 (void) memcpy(&elfhdr, buf, sizeof elfhdr);
 820                 swap = (u.c[sizeof(int32_t) - 1] + 1) != elfhdr.e_ident[5];
 821
 822                 if (getu16(swap, elfhdr.e_type) == ET_CORE) {
 823 #ifdef ELFCORE
 824                         if (dophn_core(ms, class, swap, fd,
 825 #ifdef USE_ARRAY_FOR_64BIT_TYPES
 826                             (off_t)getu32(swap, elfhdr.e_phoff[1]),
 827 #else
 828                             (off_t)getu64(swap, elfhdr.e_phoff),
 829 #endif
 830                             getu16(swap, elfhdr.e_phnum),
 831                             (size_t)getu16(swap, elfhdr.e_phentsize)) == -1)
 832                                 return -1;
 833 #else
 834                         ;
 835 #endif
 836                 } else {
 837                         if (getu16(swap, elfhdr.e_type) == ET_EXEC) {
 838                                 if (dophn_exec(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))
 846                                     == -1)
 847                                         return -1;
 848                         }
 849                         if (doshn(ms, class, swap, fd,
 850 #ifdef USE_ARRAY_FOR_64BIT_TYPES
 851                             (off_t)getu32(swap, elfhdr.e_shoff[1]),
 852 #else
 853                             (off_t)getu64(swap, elfhdr.e_shoff),
 854 #endif
 855                             getu16(swap, elfhdr.e_shnum),
 856                             (size_t)getu16(swap, elfhdr.e_shentsize)) == -1)
 857                                 return -1;
 858                 }
 859                 return 1;
 860         }
 861         return 0;
 862 }
 863 #endif