xref: /freebsd/contrib/file/src/readelf.c (revision 898496ee09ed2b7d25f6807edc4515628196ec0a)
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 #ifndef lint
30 FILE_RCSID("@(#)$File: readelf.c,v 1.190 2023/07/27 19:39:06 christos Exp $")
31 #endif
32 
33 #ifdef BUILTIN_ELF
34 #include <string.h>
35 #include <ctype.h>
36 #include <stdlib.h>
37 #ifdef HAVE_UNISTD_H
38 #include <unistd.h>
39 #endif
40 
41 #include "readelf.h"
42 #include "magic.h"
43 
44 #ifdef	ELFCORE
45 file_private int dophn_core(struct magic_set *, int, int, int, off_t, int,
46     size_t, off_t, int *, uint16_t *);
47 #endif
48 file_private int dophn_exec(struct magic_set *, int, int, int, off_t, int,
49     size_t, off_t, int, int *, uint16_t *);
50 file_private int doshn(struct magic_set *, int, int, int, off_t, int, size_t,
51     off_t, int, int, int *, uint16_t *);
52 file_private size_t donote(struct magic_set *, void *, size_t, size_t, int,
53     int, size_t, int *, uint16_t *, int, off_t, int, off_t);
54 
55 #define	ELF_ALIGN(a)	((((a) + align - 1) / align) * align)
56 
57 #define isquote(c) (strchr("'\"`", (c)) != NULL)
58 
59 file_private uint16_t getu16(int, uint16_t);
60 file_private uint32_t getu32(int, uint32_t);
61 file_private uint64_t getu64(int, uint64_t);
62 
63 #define SIZE_UNKNOWN	CAST(off_t, -1)
64 
65 file_private int
toomany(struct magic_set * ms,const char * name,uint16_t num)66 toomany(struct magic_set *ms, const char *name, uint16_t num)
67 {
68 	if (ms->flags & MAGIC_MIME)
69 		return 1;
70 	if (file_printf(ms, ", too many %s (%u)", name, num) == -1)
71 		return -1;
72 	return 1;
73 }
74 
75 file_private uint16_t
getu16(int swap,uint16_t value)76 getu16(int swap, uint16_t value)
77 {
78 	union {
79 		uint16_t ui;
80 		char c[2];
81 	} retval, tmpval;
82 
83 	if (swap) {
84 		tmpval.ui = value;
85 
86 		retval.c[0] = tmpval.c[1];
87 		retval.c[1] = tmpval.c[0];
88 
89 		return retval.ui;
90 	} else
91 		return value;
92 }
93 
94 file_private uint32_t
getu32(int swap,uint32_t value)95 getu32(int swap, uint32_t value)
96 {
97 	union {
98 		uint32_t ui;
99 		char c[4];
100 	} retval, tmpval;
101 
102 	if (swap) {
103 		tmpval.ui = value;
104 
105 		retval.c[0] = tmpval.c[3];
106 		retval.c[1] = tmpval.c[2];
107 		retval.c[2] = tmpval.c[1];
108 		retval.c[3] = tmpval.c[0];
109 
110 		return retval.ui;
111 	} else
112 		return value;
113 }
114 
115 file_private uint64_t
getu64(int swap,uint64_t value)116 getu64(int swap, uint64_t value)
117 {
118 	union {
119 		uint64_t ui;
120 		char c[8];
121 	} retval, tmpval;
122 
123 	if (swap) {
124 		tmpval.ui = value;
125 
126 		retval.c[0] = tmpval.c[7];
127 		retval.c[1] = tmpval.c[6];
128 		retval.c[2] = tmpval.c[5];
129 		retval.c[3] = tmpval.c[4];
130 		retval.c[4] = tmpval.c[3];
131 		retval.c[5] = tmpval.c[2];
132 		retval.c[6] = tmpval.c[1];
133 		retval.c[7] = tmpval.c[0];
134 
135 		return retval.ui;
136 	} else
137 		return value;
138 }
139 
140 #define elf_getu16(swap, value) getu16(swap, value)
141 #define elf_getu32(swap, value) getu32(swap, value)
142 #define elf_getu64(swap, value) getu64(swap, value)
143 
144 #define xsh_addr	(clazz == ELFCLASS32			\
145 			 ? CAST(void *, &sh32)			\
146 			 : CAST(void *, &sh64))
147 #define xsh_sizeof	(clazz == ELFCLASS32			\
148 			 ? sizeof(sh32)				\
149 			 : sizeof(sh64))
150 #define xsh_size	CAST(size_t, (clazz == ELFCLASS32	\
151 			 ? elf_getu32(swap, sh32.sh_size)	\
152 			 : elf_getu64(swap, sh64.sh_size)))
153 #define xsh_offset	CAST(off_t, (clazz == ELFCLASS32	\
154 			 ? elf_getu32(swap, sh32.sh_offset)	\
155 			 : elf_getu64(swap, sh64.sh_offset)))
156 #define xsh_type	(clazz == ELFCLASS32			\
157 			 ? elf_getu32(swap, sh32.sh_type)	\
158 			 : elf_getu32(swap, sh64.sh_type))
159 #define xsh_name    	(clazz == ELFCLASS32			\
160 			 ? elf_getu32(swap, sh32.sh_name)	\
161 			 : elf_getu32(swap, sh64.sh_name))
162 
163 #define xph_addr	(clazz == ELFCLASS32			\
164 			 ? CAST(void *, &ph32)			\
165 			 : CAST(void *, &ph64))
166 #define xph_sizeof	(clazz == ELFCLASS32			\
167 			 ? sizeof(ph32)				\
168 			 : sizeof(ph64))
169 #define xph_type	(clazz == ELFCLASS32			\
170 			 ? elf_getu32(swap, ph32.p_type)	\
171 			 : elf_getu32(swap, ph64.p_type))
172 #define xph_offset	CAST(off_t, (clazz == ELFCLASS32	\
173 			 ? elf_getu32(swap, ph32.p_offset)	\
174 			 : elf_getu64(swap, ph64.p_offset)))
175 #define xph_align	CAST(size_t, (clazz == ELFCLASS32	\
176 			 ? CAST(off_t, (ph32.p_align ? 		\
177 			    elf_getu32(swap, ph32.p_align) : 4))\
178 			 : CAST(off_t, (ph64.p_align ?		\
179 			    elf_getu64(swap, ph64.p_align) : 4))))
180 #define xph_vaddr	CAST(size_t, (clazz == ELFCLASS32	\
181 			 ? CAST(off_t, (ph32.p_vaddr ? 		\
182 			    elf_getu32(swap, ph32.p_vaddr) : 4))\
183 			 : CAST(off_t, (ph64.p_vaddr ?		\
184 			    elf_getu64(swap, ph64.p_vaddr) : 4))))
185 #define xph_filesz	CAST(size_t, (clazz == ELFCLASS32	\
186 			 ? elf_getu32(swap, ph32.p_filesz)	\
187 			 : elf_getu64(swap, ph64.p_filesz)))
188 #define xph_memsz	CAST(size_t, ((clazz == ELFCLASS32	\
189 			 ? elf_getu32(swap, ph32.p_memsz)	\
190 			 : elf_getu64(swap, ph64.p_memsz))))
191 #define xnh_addr	(clazz == ELFCLASS32			\
192 			 ? CAST(void *, &nh32)			\
193 			 : CAST(void *, &nh64))
194 #define xnh_sizeof	(clazz == ELFCLASS32			\
195 			 ? sizeof(nh32)				\
196 			 : sizeof(nh64))
197 #define xnh_type	(clazz == ELFCLASS32			\
198 			 ? elf_getu32(swap, nh32.n_type)	\
199 			 : elf_getu32(swap, nh64.n_type))
200 #define xnh_namesz	(clazz == ELFCLASS32			\
201 			 ? elf_getu32(swap, nh32.n_namesz)	\
202 			 : elf_getu32(swap, nh64.n_namesz))
203 #define xnh_descsz	(clazz == ELFCLASS32			\
204 			 ? elf_getu32(swap, nh32.n_descsz)	\
205 			 : elf_getu32(swap, nh64.n_descsz))
206 
207 #define xdh_addr	(clazz == ELFCLASS32			\
208 			 ? CAST(void *, &dh32)			\
209 			 : CAST(void *, &dh64))
210 #define xdh_sizeof	(clazz == ELFCLASS32			\
211 			 ? sizeof(dh32)				\
212 			 : sizeof(dh64))
213 #define xdh_tag		(clazz == ELFCLASS32			\
214 			 ? elf_getu32(swap, dh32.d_tag)		\
215 			 : elf_getu64(swap, dh64.d_tag))
216 #define xdh_val		(clazz == ELFCLASS32			\
217 			 ? elf_getu32(swap, dh32.d_un.d_val)	\
218 			 : elf_getu64(swap, dh64.d_un.d_val))
219 
220 #define xcap_addr	(clazz == ELFCLASS32			\
221 			 ? CAST(void *, &cap32)			\
222 			 : CAST(void *, &cap64))
223 #define xcap_sizeof	(clazz == ELFCLASS32			\
224 			 ? sizeof(cap32)			\
225 			 : sizeof(cap64))
226 #define xcap_tag	(clazz == ELFCLASS32			\
227 			 ? elf_getu32(swap, cap32.c_tag)	\
228 			 : elf_getu64(swap, cap64.c_tag))
229 #define xcap_val	(clazz == ELFCLASS32			\
230 			 ? elf_getu32(swap, cap32.c_un.c_val)	\
231 			 : elf_getu64(swap, cap64.c_un.c_val))
232 
233 #define xauxv_addr	(clazz == ELFCLASS32			\
234 			 ? CAST(void *, &auxv32)		\
235 			 : CAST(void *, &auxv64))
236 #define xauxv_sizeof	(clazz == ELFCLASS32			\
237 			 ? sizeof(auxv32)			\
238 			 : sizeof(auxv64))
239 #define xauxv_type	(clazz == ELFCLASS32			\
240 			 ? elf_getu32(swap, auxv32.a_type)	\
241 			 : elf_getu64(swap, auxv64.a_type))
242 #define xauxv_val	(clazz == ELFCLASS32			\
243 			 ? elf_getu32(swap, auxv32.a_v)		\
244 			 : elf_getu64(swap, auxv64.a_v))
245 
246 #define prpsoffsets(i)	(clazz == ELFCLASS32			\
247 			 ? prpsoffsets32[i]			\
248 			 : prpsoffsets64[i])
249 
250 #ifdef ELFCORE
251 /*
252  * Try larger offsets first to avoid false matches
253  * from earlier data that happen to look like strings.
254  */
255 static const size_t	prpsoffsets32[] = {
256 #ifdef USE_NT_PSINFO
257 	104,		/* SunOS 5.x (command line) */
258 	88,		/* SunOS 5.x (short name) */
259 #endif /* USE_NT_PSINFO */
260 
261 	100,		/* SunOS 5.x (command line) */
262 	84,		/* SunOS 5.x (short name) */
263 
264 	44,		/* Linux (command line) */
265 	28,		/* Linux (short name) */
266 
267 	48,		/* Linux PowerPC (command line) */
268 	32,		/* Linux PowerPC (short name) */
269 
270 	8,		/* FreeBSD */
271 };
272 
273 static const size_t	prpsoffsets64[] = {
274 #ifdef USE_NT_PSINFO
275 	152,		/* SunOS 5.x (command line) */
276 	136,		/* SunOS 5.x (short name) */
277 #endif /* USE_NT_PSINFO */
278 
279 	136,		/* SunOS 5.x, 64-bit (command line) */
280 	120,		/* SunOS 5.x, 64-bit (short name) */
281 
282 	56,		/* Linux (command line) */
283 	40,             /* Linux (tested on core from 2.4.x, short name) */
284 
285 	16,		/* FreeBSD, 64-bit */
286 };
287 
288 #define	NOFFSETS32	__arraycount(prpsoffsets32)
289 #define NOFFSETS64	__arraycount(prpsoffsets64)
290 
291 #define NOFFSETS	(clazz == ELFCLASS32 ? NOFFSETS32 : NOFFSETS64)
292 
293 /*
294  * Look through the program headers of an executable image, searching
295  * for a PT_NOTE section of type NT_PRPSINFO, with a name "CORE" or
296  * "FreeBSD"; if one is found, try looking in various places in its
297  * contents for a 16-character string containing only printable
298  * characters - if found, that string should be the name of the program
299  * that dropped core.  Note: right after that 16-character string is,
300  * at least in SunOS 5.x (and possibly other SVR4-flavored systems) and
301  * Linux, a longer string (80 characters, in 5.x, probably other
302  * SVR4-flavored systems, and Linux) containing the start of the
303  * command line for that program.
304  *
305  * SunOS 5.x core files contain two PT_NOTE sections, with the types
306  * NT_PRPSINFO (old) and NT_PSINFO (new).  These structs contain the
307  * same info about the command name and command line, so it probably
308  * isn't worthwhile to look for NT_PSINFO, but the offsets are provided
309  * above (see USE_NT_PSINFO), in case we ever decide to do so.  The
310  * NT_PRPSINFO and NT_PSINFO sections are always in order and adjacent;
311  * the SunOS 5.x file command relies on this (and prefers the latter).
312  *
313  * The signal number probably appears in a section of type NT_PRSTATUS,
314  * but that's also rather OS-dependent, in ways that are harder to
315  * dissect with heuristics, so I'm not bothering with the signal number.
316  * (I suppose the signal number could be of interest in situations where
317  * you don't have the binary of the program that dropped core; if you
318  * *do* have that binary, the debugger will probably tell you what
319  * signal it was.)
320  */
321 
322 #define	OS_STYLE_SVR4		0
323 #define	OS_STYLE_FREEBSD	1
324 #define	OS_STYLE_NETBSD		2
325 
326 file_private const char os_style_names[][8] = {
327 	"SVR4",
328 	"FreeBSD",
329 	"NetBSD",
330 };
331 
332 #define FLAGS_CORE_STYLE		0x0003
333 
334 #define FLAGS_DID_CORE			0x0004
335 #define FLAGS_DID_OS_NOTE		0x0008
336 #define FLAGS_DID_BUILD_ID		0x0010
337 #define FLAGS_DID_CORE_STYLE		0x0020
338 #define FLAGS_DID_NETBSD_PAX		0x0040
339 #define FLAGS_DID_NETBSD_MARCH		0x0080
340 #define FLAGS_DID_NETBSD_CMODEL		0x0100
341 #define FLAGS_DID_NETBSD_EMULATION	0x0200
342 #define FLAGS_DID_NETBSD_UNKNOWN	0x0400
343 #define FLAGS_IS_CORE			0x0800
344 #define FLAGS_DID_AUXV			0x1000
345 
346 file_private int
dophn_core(struct magic_set * ms,int clazz,int swap,int fd,off_t off,int num,size_t size,off_t fsize,int * flags,uint16_t * notecount)347 dophn_core(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
348     int num, size_t size, off_t fsize, int *flags, uint16_t *notecount)
349 {
350 	Elf32_Phdr ph32;
351 	Elf64_Phdr ph64;
352 	size_t offset, len;
353 	unsigned char nbuf[BUFSIZ];
354 	ssize_t bufsize;
355 	off_t ph_off = off, offs;
356 	int ph_num = num;
357 
358 	if (ms->flags & MAGIC_MIME)
359 		return 0;
360 
361 	if (num == 0) {
362 		if (file_printf(ms, ", no program header") == -1)
363 			return -1;
364 		return 0;
365 	}
366 	if (size != xph_sizeof) {
367 		if (file_printf(ms, ", corrupted program header size") == -1)
368 			return -1;
369 		return 0;
370 	}
371 
372 	/*
373 	 * Loop through all the program headers.
374 	 */
375 	for ( ; num; num--) {
376 		if (pread(fd, xph_addr, xph_sizeof, off) <
377 		    CAST(ssize_t, xph_sizeof)) {
378 			if (file_printf(ms,
379 			    ", can't read elf program headers at %jd",
380 			    (intmax_t)off) == -1)
381 				return -1;
382 			return 0;
383 		}
384 		off += size;
385 
386 		if (fsize != SIZE_UNKNOWN && xph_offset > fsize) {
387 			/* Perhaps warn here */
388 			continue;
389 		}
390 
391 		if (xph_type != PT_NOTE)
392 			continue;
393 
394 		/*
395 		 * This is a PT_NOTE section; loop through all the notes
396 		 * in the section.
397 		 */
398 		len = xph_filesz < sizeof(nbuf) ? xph_filesz : sizeof(nbuf);
399 		offs = xph_offset;
400 		if ((bufsize = pread(fd, nbuf, len, offs)) == -1) {
401 			if (file_printf(ms, " can't read note section at %jd",
402 			    (intmax_t)offs) == -1)
403 				return -1;
404 			return 0;
405 		}
406 		offset = 0;
407 		for (;;) {
408 			if (offset >= CAST(size_t, bufsize))
409 				break;
410 			offset = donote(ms, nbuf, offset, CAST(size_t, bufsize),
411 			    clazz, swap, 4, flags, notecount, fd, ph_off,
412 			    ph_num, fsize);
413 			if (offset == 0)
414 				break;
415 
416 		}
417 	}
418 	return 0;
419 }
420 #endif
421 
422 static int
do_note_netbsd_version(struct magic_set * ms,int swap,void * v)423 do_note_netbsd_version(struct magic_set *ms, int swap, void *v)
424 {
425 	uint32_t desc;
426 	memcpy(&desc, v, sizeof(desc));
427 	desc = elf_getu32(swap, desc);
428 
429 	if (file_printf(ms, ", for NetBSD") == -1)
430 		return -1;
431 	/*
432 	 * The version number used to be stuck as 199905, and was thus
433 	 * basically content-free.  Newer versions of NetBSD have fixed
434 	 * this and now use the encoding of __NetBSD_Version__:
435 	 *
436 	 *	MMmmrrpp00
437 	 *
438 	 * M = major version
439 	 * m = minor version
440 	 * r = release ["",A-Z,Z[A-Z] but numeric]
441 	 * p = patchlevel
442 	 */
443 	if (desc > 100000000U) {
444 		uint32_t ver_patch = (desc / 100) % 100;
445 		uint32_t ver_rel = (desc / 10000) % 100;
446 		uint32_t ver_min = (desc / 1000000) % 100;
447 		uint32_t ver_maj = desc / 100000000;
448 
449 		if (file_printf(ms, " %u.%u", ver_maj, ver_min) == -1)
450 			return -1;
451 		if (ver_maj >= 9) {
452 			ver_patch += 100 * ver_rel;
453 			ver_rel = 0;
454 		}
455 		if (ver_rel == 0 && ver_patch != 0) {
456 			if (file_printf(ms, ".%u", ver_patch) == -1)
457 				return -1;
458 		} else if (ver_rel != 0) {
459 			while (ver_rel > 26) {
460 				if (file_printf(ms, "Z") == -1)
461 					return -1;
462 				ver_rel -= 26;
463 			}
464 			if (file_printf(ms, "%c", 'A' + ver_rel - 1) == -1)
465 				return -1;
466 		}
467 	}
468 	return 0;
469 }
470 
471 static int
do_note_freebsd_version(struct magic_set * ms,int swap,void * v)472 do_note_freebsd_version(struct magic_set *ms, int swap, void *v)
473 {
474 	uint32_t desc;
475 
476 	memcpy(&desc, v, sizeof(desc));
477 	desc = elf_getu32(swap, desc);
478 	if (file_printf(ms, ", for FreeBSD") == -1)
479 		return -1;
480 
481 	/*
482 	 * Contents is __FreeBSD_version, whose relation to OS
483 	 * versions is defined by a huge table in the Porter's
484 	 * Handbook.  This is the general scheme:
485 	 *
486 	 * Releases:
487 	 * 	Mmp000 (before 4.10)
488 	 * 	Mmi0p0 (before 5.0)
489 	 * 	Mmm0p0
490 	 *
491 	 * Development branches:
492 	 * 	Mmpxxx (before 4.6)
493 	 * 	Mmp1xx (before 4.10)
494 	 * 	Mmi1xx (before 5.0)
495 	 * 	M000xx (pre-M.0)
496 	 * 	Mmm1xx
497 	 *
498 	 * M = major version
499 	 * m = minor version
500 	 * i = minor version increment (491000 -> 4.10)
501 	 * p = patchlevel
502 	 * x = revision
503 	 *
504 	 * The first release of FreeBSD to use ELF by default
505 	 * was version 3.0.
506 	 */
507 	if (desc == 460002) {
508 		if (file_printf(ms, " 4.6.2") == -1)
509 			return -1;
510 	} else if (desc < 460100) {
511 		if (file_printf(ms, " %d.%d", desc / 100000,
512 		    desc / 10000 % 10) == -1)
513 			return -1;
514 		if (desc / 1000 % 10 > 0)
515 			if (file_printf(ms, ".%d", desc / 1000 % 10) == -1)
516 				return -1;
517 		if ((desc % 1000 > 0) || (desc % 100000 == 0))
518 			if (file_printf(ms, " (%d)", desc) == -1)
519 				return -1;
520 	} else if (desc < 500000) {
521 		if (file_printf(ms, " %d.%d", desc / 100000,
522 		    desc / 10000 % 10 + desc / 1000 % 10) == -1)
523 			return -1;
524 		if (desc / 100 % 10 > 0) {
525 			if (file_printf(ms, " (%d)", desc) == -1)
526 				return -1;
527 		} else if (desc / 10 % 10 > 0) {
528 			if (file_printf(ms, ".%d", desc / 10 % 10) == -1)
529 				return -1;
530 		}
531 	} else {
532 		if (file_printf(ms, " %d.%d", desc / 100000,
533 		    desc / 1000 % 100) == -1)
534 			return -1;
535 		if ((desc / 100 % 10 > 0) ||
536 		    (desc % 100000 / 100 == 0)) {
537 			if (file_printf(ms, " (%d)", desc) == -1)
538 				return -1;
539 		} else if (desc / 10 % 10 > 0) {
540 			if (file_printf(ms, ".%d", desc / 10 % 10) == -1)
541 				return -1;
542 		}
543 	}
544 	return 0;
545 }
546 
547 file_private int
548 /*ARGSUSED*/
do_bid_note(struct magic_set * ms,unsigned char * nbuf,uint32_t type,int swap,uint32_t namesz,uint32_t descsz,size_t noff,size_t doff,int * flags)549 do_bid_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
550     int swap __attribute__((__unused__)), uint32_t namesz, uint32_t descsz,
551     size_t noff, size_t doff, int *flags)
552 {
553 	if (namesz == 4 && strcmp(RCAST(char *, &nbuf[noff]), "GNU") == 0 &&
554 	    type == NT_GNU_BUILD_ID && (descsz >= 4 && descsz <= 20)) {
555 		uint8_t desc[20];
556 		const char *btype;
557 		uint32_t i;
558 		*flags |= FLAGS_DID_BUILD_ID;
559 		switch (descsz) {
560 		case 8:
561 		    btype = "xxHash";
562 		    break;
563 		case 16:
564 		    btype = "md5/uuid";
565 		    break;
566 		case 20:
567 		    btype = "sha1";
568 		    break;
569 		default:
570 		    btype = "unknown";
571 		    break;
572 		}
573 		if (file_printf(ms, ", BuildID[%s]=", btype) == -1)
574 			return -1;
575 		memcpy(desc, &nbuf[doff], descsz);
576 		for (i = 0; i < descsz; i++)
577 		    if (file_printf(ms, "%02x", desc[i]) == -1)
578 			return -1;
579 		return 1;
580 	}
581 	if (namesz == 4 && strcmp(RCAST(char *, &nbuf[noff]), "Go") == 0 &&
582 	    type == NT_GO_BUILD_ID && descsz < 128) {
583 		char buf[256];
584 		if (file_printf(ms, ", Go BuildID=%s",
585 		    file_copystr(buf, sizeof(buf), descsz,
586 		    RCAST(const char *, &nbuf[doff]))) == -1)
587 			return -1;
588 		return 1;
589 	}
590 	return 0;
591 }
592 
593 file_private int
do_os_note(struct magic_set * ms,unsigned char * nbuf,uint32_t type,int swap,uint32_t namesz,uint32_t descsz,size_t noff,size_t doff,int * flags)594 do_os_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
595     int swap, uint32_t namesz, uint32_t descsz,
596     size_t noff, size_t doff, int *flags)
597 {
598 	const char *name = RCAST(const char *, &nbuf[noff]);
599 
600 	if (namesz == 5 && strcmp(name, "SuSE") == 0 &&
601 		type == NT_GNU_VERSION && descsz == 2) {
602 		*flags |= FLAGS_DID_OS_NOTE;
603 		if (file_printf(ms, ", for SuSE %d.%d", nbuf[doff],
604 		    nbuf[doff + 1]) == -1)
605 		    return -1;
606 	    return 1;
607 	}
608 
609 	if (namesz == 4 && strcmp(name, "GNU") == 0 &&
610 	    type == NT_GNU_VERSION && descsz == 16) {
611 		uint32_t desc[4];
612 		memcpy(desc, &nbuf[doff], sizeof(desc));
613 
614 		*flags |= FLAGS_DID_OS_NOTE;
615 		if (file_printf(ms, ", for GNU/") == -1)
616 			return -1;
617 		switch (elf_getu32(swap, desc[0])) {
618 		case GNU_OS_LINUX:
619 			if (file_printf(ms, "Linux") == -1)
620 				return -1;
621 			break;
622 		case GNU_OS_HURD:
623 			if (file_printf(ms, "Hurd") == -1)
624 				return -1;
625 			break;
626 		case GNU_OS_SOLARIS:
627 			if (file_printf(ms, "Solaris") == -1)
628 				return -1;
629 			break;
630 		case GNU_OS_KFREEBSD:
631 			if (file_printf(ms, "kFreeBSD") == -1)
632 				return -1;
633 			break;
634 		case GNU_OS_KNETBSD:
635 			if (file_printf(ms, "kNetBSD") == -1)
636 				return -1;
637 			break;
638 		default:
639 			if (file_printf(ms, "<unknown>") == -1)
640 				return -1;
641 		}
642 		if (file_printf(ms, " %d.%d.%d", elf_getu32(swap, desc[1]),
643 		    elf_getu32(swap, desc[2]), elf_getu32(swap, desc[3])) == -1)
644 			return -1;
645 		return 1;
646 	}
647 
648 	if (namesz == 7 && strcmp(name, "NetBSD") == 0) {
649 	    	if (type == NT_NETBSD_VERSION && descsz == 4) {
650 			*flags |= FLAGS_DID_OS_NOTE;
651 			if (do_note_netbsd_version(ms, swap, &nbuf[doff]) == -1)
652 				return -1;
653 			return 1;
654 		}
655 	}
656 
657 	if (namesz == 8 && strcmp(name, "FreeBSD") == 0) {
658 	    	if (type == NT_FREEBSD_VERSION && descsz == 4) {
659 			*flags |= FLAGS_DID_OS_NOTE;
660 			if (do_note_freebsd_version(ms, swap, &nbuf[doff])
661 			    == -1)
662 				return -1;
663 			return 1;
664 		}
665 	}
666 
667 	if (namesz == 8 && strcmp(name, "OpenBSD") == 0 &&
668 	    type == NT_OPENBSD_VERSION && descsz == 4) {
669 		*flags |= FLAGS_DID_OS_NOTE;
670 		if (file_printf(ms, ", for OpenBSD") == -1)
671 			return -1;
672 		/* Content of note is always 0 */
673 		return 1;
674 	}
675 
676 	if (namesz == 10 && strcmp(name, "DragonFly") == 0 &&
677 	    type == NT_DRAGONFLY_VERSION && descsz == 4) {
678 		uint32_t desc;
679 		*flags |= FLAGS_DID_OS_NOTE;
680 		if (file_printf(ms, ", for DragonFly") == -1)
681 			return -1;
682 		memcpy(&desc, &nbuf[doff], sizeof(desc));
683 		desc = elf_getu32(swap, desc);
684 		if (file_printf(ms, " %d.%d.%d", desc / 100000,
685 		    desc / 10000 % 10, desc % 10000) == -1)
686 			return -1;
687 		return 1;
688 	}
689 	return 0;
690 }
691 
692 file_private int
do_pax_note(struct magic_set * ms,unsigned char * nbuf,uint32_t type,int swap,uint32_t namesz,uint32_t descsz,size_t noff,size_t doff,int * flags)693 do_pax_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
694     int swap, uint32_t namesz, uint32_t descsz,
695     size_t noff, size_t doff, int *flags)
696 {
697 	const char *name = RCAST(const char *, &nbuf[noff]);
698 
699 	if (namesz == 4 && strcmp(name, "PaX") == 0 &&
700 	    type == NT_NETBSD_PAX && descsz == 4) {
701 		static const char *pax[] = {
702 		    "+mprotect",
703 		    "-mprotect",
704 		    "+segvguard",
705 		    "-segvguard",
706 		    "+ASLR",
707 		    "-ASLR",
708 		};
709 		uint32_t desc;
710 		size_t i;
711 		int did = 0;
712 
713 		*flags |= FLAGS_DID_NETBSD_PAX;
714 		memcpy(&desc, &nbuf[doff], sizeof(desc));
715 		desc = elf_getu32(swap, desc);
716 
717 		if (desc && file_printf(ms, ", PaX: ") == -1)
718 			return -1;
719 
720 		for (i = 0; i < __arraycount(pax); i++) {
721 			if (((1 << CAST(int, i)) & desc) == 0)
722 				continue;
723 			if (file_printf(ms, "%s%s", did++ ? "," : "",
724 			    pax[i]) == -1)
725 				return -1;
726 		}
727 		return 1;
728 	}
729 	return 0;
730 }
731 
732 file_private int
do_core_note(struct magic_set * ms,unsigned char * nbuf,uint32_t type,int swap,uint32_t namesz,uint32_t descsz,size_t noff,size_t doff,int * flags,size_t size,int clazz)733 do_core_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
734     int swap, uint32_t namesz, uint32_t descsz,
735     size_t noff, size_t doff, int *flags, size_t size, int clazz)
736 {
737 #ifdef ELFCORE
738 	char buf[256];
739 	const char *name = RCAST(const char *, &nbuf[noff]);
740 
741 	int os_style = -1;
742 	/*
743 	 * Sigh.  The 2.0.36 kernel in Debian 2.1, at
744 	 * least, doesn't correctly implement name
745 	 * sections, in core dumps, as specified by
746 	 * the "Program Linking" section of "UNIX(R) System
747 	 * V Release 4 Programmer's Guide: ANSI C and
748 	 * Programming Support Tools", because my copy
749 	 * clearly says "The first 'namesz' bytes in 'name'
750 	 * contain a *null-terminated* [emphasis mine]
751 	 * character representation of the entry's owner
752 	 * or originator", but the 2.0.36 kernel code
753 	 * doesn't include the terminating null in the
754 	 * name....
755 	 */
756 	if ((namesz == 4 && strncmp(name, "CORE", 4) == 0) ||
757 	    (namesz == 5 && strcmp(name, "CORE") == 0)) {
758 		os_style = OS_STYLE_SVR4;
759 	}
760 
761 	if ((namesz == 8 && strcmp(name, "FreeBSD") == 0)) {
762 		os_style = OS_STYLE_FREEBSD;
763 	}
764 
765 	if ((namesz >= 11 && strncmp(name, "NetBSD-CORE", 11)
766 	    == 0)) {
767 		os_style = OS_STYLE_NETBSD;
768 	}
769 
770 	if (os_style != -1 && (*flags & FLAGS_DID_CORE_STYLE) == 0) {
771 		if (file_printf(ms, ", %s-style", os_style_names[os_style])
772 		    == -1)
773 			return -1;
774 		*flags |= FLAGS_DID_CORE_STYLE;
775 		*flags |= os_style;
776 	}
777 
778 	switch (os_style) {
779 	case OS_STYLE_NETBSD:
780 		if (type == NT_NETBSD_CORE_PROCINFO) {
781 			char sbuf[512];
782 			struct NetBSD_elfcore_procinfo pi;
783 			memset(&pi, 0, sizeof(pi));
784 			memcpy(&pi, nbuf + doff, MIN(descsz, sizeof(pi)));
785 
786 			if (file_printf(ms, ", from '%.31s', pid=%u, uid=%u, "
787 			    "gid=%u, nlwps=%u, lwp=%u (signal %u/code %u)",
788 			    file_printable(ms, sbuf, sizeof(sbuf),
789 			    RCAST(char *, pi.cpi_name), sizeof(pi.cpi_name)),
790 			    elf_getu32(swap, CAST(uint32_t, pi.cpi_pid)),
791 			    elf_getu32(swap, pi.cpi_euid),
792 			    elf_getu32(swap, pi.cpi_egid),
793 			    elf_getu32(swap, pi.cpi_nlwps),
794 			    elf_getu32(swap, CAST(uint32_t, pi.cpi_siglwp)),
795 			    elf_getu32(swap, pi.cpi_signo),
796 			    elf_getu32(swap, pi.cpi_sigcode)) == -1)
797 				return -1;
798 
799 			*flags |= FLAGS_DID_CORE;
800 			return 1;
801 		}
802 		break;
803 
804 	case OS_STYLE_FREEBSD:
805 		if (type == NT_PRPSINFO && *flags & FLAGS_IS_CORE) {
806 			size_t argoff, pidoff;
807 
808 			if (clazz == ELFCLASS32)
809 				argoff = 4 + 4 + 17;
810 			else
811 				argoff = 4 + 4 + 8 + 17;
812 			if (file_printf(ms, ", from '%.80s'", nbuf + doff +
813 			    argoff) == -1)
814 				return -1;
815 			pidoff = argoff + 81 + 2;
816 			if (doff + pidoff + 4 <= size) {
817 				if (file_printf(ms, ", pid=%u",
818 				    elf_getu32(swap, *RCAST(uint32_t *, (nbuf +
819 				    doff + pidoff)))) == -1)
820 					return -1;
821 			}
822 			*flags |= FLAGS_DID_CORE;
823 		}
824 		break;
825 
826 	default:
827 		if (type == NT_PRPSINFO && *flags & FLAGS_IS_CORE) {
828 			size_t i, j;
829 			unsigned char c;
830 			/*
831 			 * Extract the program name.  We assume
832 			 * it to be 16 characters (that's what it
833 			 * is in SunOS 5.x and Linux).
834 			 *
835 			 * Unfortunately, it's at a different offset
836 			 * in various OSes, so try multiple offsets.
837 			 * If the characters aren't all printable,
838 			 * reject it.
839 			 */
840 			for (i = 0; i < NOFFSETS; i++) {
841 				unsigned char *cname, *cp;
842 				size_t reloffset = prpsoffsets(i);
843 				size_t noffset = doff + reloffset;
844 				size_t k;
845 				for (j = 0; j < 16; j++, noffset++,
846 				    reloffset++) {
847 					/*
848 					 * Make sure we're not past
849 					 * the end of the buffer; if
850 					 * we are, just give up.
851 					 */
852 					if (noffset >= size)
853 						goto tryanother;
854 
855 					/*
856 					 * Make sure we're not past
857 					 * the end of the contents;
858 					 * if we are, this obviously
859 					 * isn't the right offset.
860 					 */
861 					if (reloffset >= descsz)
862 						goto tryanother;
863 
864 					c = nbuf[noffset];
865 					if (c == '\0') {
866 						/*
867 						 * A '\0' at the
868 						 * beginning is
869 						 * obviously wrong.
870 						 * Any other '\0'
871 						 * means we're done.
872 						 */
873 						if (j == 0)
874 							goto tryanother;
875 						else
876 							break;
877 					} else {
878 						/*
879 						 * A nonprintable
880 						 * character is also
881 						 * wrong.
882 						 */
883 						if (!isprint(c) || isquote(c))
884 							goto tryanother;
885 					}
886 				}
887 				/*
888 				 * Well, that worked.
889 				 */
890 
891 				/*
892 				 * Try next offsets, in case this match is
893 				 * in the middle of a string.
894 				 */
895 				for (k = i + 1 ; k < NOFFSETS; k++) {
896 					size_t no;
897 					int adjust = 1;
898 					if (prpsoffsets(k) >= prpsoffsets(i))
899 						continue;
900 					/*
901 					 * pr_fname == pr_psargs - 16 &&
902 					 * non-nul-terminated fname (qemu)
903 					 */
904 					if (prpsoffsets(k) ==
905 					    prpsoffsets(i) - 16 && j == 16)
906 						continue;
907 					for (no = doff + prpsoffsets(k);
908 					     no < doff + prpsoffsets(i); no++)
909 						adjust = adjust
910 						         && isprint(nbuf[no]);
911 					if (adjust)
912 						i = k;
913 				}
914 
915 				cname = CAST(unsigned char *,
916 				    &nbuf[doff + prpsoffsets(i)]);
917 				for (cp = cname; cp < nbuf + size && *cp
918 				    && isprint(*cp); cp++)
919 					continue;
920 				/*
921 				 * Linux apparently appends a space at the end
922 				 * of the command line: remove it.
923 				 */
924 				while (cp > cname && isspace(cp[-1]))
925 					cp--;
926 				if (file_printf(ms, ", from '%s'",
927 				    file_copystr(buf, sizeof(buf),
928 				    CAST(size_t, cp - cname),
929 				    RCAST(char *, cname))) == -1)
930 					return -1;
931 				*flags |= FLAGS_DID_CORE;
932 				return 1;
933 
934 			tryanother:
935 				;
936 			}
937 		}
938 		break;
939 	}
940 #endif
941 	return 0;
942 }
943 
944 file_private off_t
get_offset_from_virtaddr(struct magic_set * ms,int swap,int clazz,int fd,off_t off,int num,off_t fsize,uint64_t virtaddr)945 get_offset_from_virtaddr(struct magic_set *ms, int swap, int clazz, int fd,
946     off_t off, int num, off_t fsize, uint64_t virtaddr)
947 {
948 	Elf32_Phdr ph32;
949 	Elf64_Phdr ph64;
950 
951 	/*
952 	 * Loop through all the program headers and find the header with
953 	 * virtual address in which the "virtaddr" belongs to.
954 	 */
955 	for ( ; num; num--) {
956 		if (pread(fd, xph_addr, xph_sizeof, off) <
957 		    CAST(ssize_t, xph_sizeof)) {
958 			if (file_printf(ms,
959 			    ", can't read elf program header at %jd",
960 			    (intmax_t)off) == -1)
961 				return -1;
962 			return 0;
963 
964 		}
965 		off += xph_sizeof;
966 
967 		if (fsize != SIZE_UNKNOWN && xph_offset > fsize) {
968 			/* Perhaps warn here */
969 			continue;
970 		}
971 
972 		if (virtaddr >= xph_vaddr && virtaddr < xph_vaddr + xph_filesz)
973 			return xph_offset + (virtaddr - xph_vaddr);
974 	}
975 	return 0;
976 }
977 
978 file_private size_t
get_string_on_virtaddr(struct magic_set * ms,int swap,int clazz,int fd,off_t ph_off,int ph_num,off_t fsize,uint64_t virtaddr,char * buf,ssize_t buflen)979 get_string_on_virtaddr(struct magic_set *ms,
980     int swap, int clazz, int fd, off_t ph_off, int ph_num,
981     off_t fsize, uint64_t virtaddr, char *buf, ssize_t buflen)
982 {
983 	char *bptr;
984 	off_t offset;
985 
986 	if (buflen == 0)
987 		return 0;
988 
989 	offset = get_offset_from_virtaddr(ms, swap, clazz, fd, ph_off, ph_num,
990 	    fsize, virtaddr);
991 	if (offset < 0 ||
992 	    (buflen = pread(fd, buf, CAST(size_t, buflen), offset)) <= 0) {
993 		(void)file_printf(ms, ", can't read elf string at %jd",
994 		    (intmax_t)offset);
995 		return 0;
996 	}
997 
998 	buf[buflen - 1] = '\0';
999 
1000 	/* We expect only printable characters, so return if buffer contains
1001 	 * non-printable character before the '\0' or just '\0'. */
1002 	for (bptr = buf; *bptr && isprint(CAST(unsigned char, *bptr)); bptr++)
1003 		continue;
1004 	if (*bptr != '\0')
1005 		return 0;
1006 
1007 	return bptr - buf;
1008 }
1009 
1010 
1011 /*ARGSUSED*/
1012 file_private int
do_auxv_note(struct magic_set * ms,unsigned char * nbuf,uint32_t type,int swap,uint32_t namesz,uint32_t descsz,size_t noff,size_t doff,int * flags,size_t size,int clazz,int fd,off_t ph_off,int ph_num,off_t fsize)1013 do_auxv_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
1014     int swap, uint32_t namesz __attribute__((__unused__)),
1015     uint32_t descsz __attribute__((__unused__)),
1016     size_t noff __attribute__((__unused__)), size_t doff,
1017     int *flags, size_t size __attribute__((__unused__)), int clazz,
1018     int fd, off_t ph_off, int ph_num, off_t fsize)
1019 {
1020 #ifdef ELFCORE
1021 	Aux32Info auxv32;
1022 	Aux64Info auxv64;
1023 	size_t elsize = xauxv_sizeof;
1024 	const char *tag;
1025 	int is_string;
1026 	size_t nval, off;
1027 
1028 	if ((*flags & (FLAGS_IS_CORE|FLAGS_DID_CORE_STYLE)) !=
1029 	    (FLAGS_IS_CORE|FLAGS_DID_CORE_STYLE))
1030 		return 0;
1031 
1032 	switch (*flags & FLAGS_CORE_STYLE) {
1033 	case OS_STYLE_SVR4:
1034 		if (type != NT_AUXV)
1035 			return 0;
1036 		break;
1037 #ifdef notyet
1038 	case OS_STYLE_NETBSD:
1039 		if (type != NT_NETBSD_CORE_AUXV)
1040 			return 0;
1041 		break;
1042 	case OS_STYLE_FREEBSD:
1043 		if (type != NT_FREEBSD_PROCSTAT_AUXV)
1044 			return 0;
1045 		break;
1046 #endif
1047 	default:
1048 		return 0;
1049 	}
1050 
1051 	*flags |= FLAGS_DID_AUXV;
1052 
1053 	nval = 0;
1054 	for (off = 0; off + elsize <= descsz; off += elsize) {
1055 		memcpy(xauxv_addr, &nbuf[doff + off], xauxv_sizeof);
1056 		/* Limit processing to 50 vector entries to prevent DoS */
1057 		if (nval++ >= 50) {
1058 			file_error(ms, 0, "Too many ELF Auxv elements");
1059 			return 1;
1060 		}
1061 
1062 		switch(xauxv_type) {
1063 		case AT_LINUX_EXECFN:
1064 			is_string = 1;
1065 			tag = "execfn";
1066 			break;
1067 		case AT_LINUX_PLATFORM:
1068 			is_string = 1;
1069 			tag = "platform";
1070 			break;
1071 		case AT_LINUX_UID:
1072 			is_string = 0;
1073 			tag = "real uid";
1074 			break;
1075 		case AT_LINUX_GID:
1076 			is_string = 0;
1077 			tag = "real gid";
1078 			break;
1079 		case AT_LINUX_EUID:
1080 			is_string = 0;
1081 			tag = "effective uid";
1082 			break;
1083 		case AT_LINUX_EGID:
1084 			is_string = 0;
1085 			tag = "effective gid";
1086 			break;
1087 		default:
1088 			is_string = 0;
1089 			tag = NULL;
1090 			break;
1091 		}
1092 
1093 		if (tag == NULL)
1094 			continue;
1095 
1096 		if (is_string) {
1097 			char buf[256];
1098 			ssize_t buflen;
1099 			buflen = get_string_on_virtaddr(ms, swap, clazz, fd,
1100 			    ph_off, ph_num, fsize, xauxv_val, buf, sizeof(buf));
1101 
1102 			if (buflen == 0)
1103 				continue;
1104 
1105 			if (file_printf(ms, ", %s: '%s'", tag, buf) == -1)
1106 				return -1;
1107 		} else {
1108 			if (file_printf(ms, ", %s: %d", tag,
1109 			    CAST(int, xauxv_val)) == -1)
1110 				return -1;
1111 		}
1112 	}
1113 	return 1;
1114 #else
1115 	return 0;
1116 #endif
1117 }
1118 
1119 file_private size_t
dodynamic(struct magic_set * ms,void * vbuf,size_t offset,size_t size,int clazz,int swap,int * pie,size_t * need)1120 dodynamic(struct magic_set *ms, void *vbuf, size_t offset, size_t size,
1121     int clazz, int swap, int *pie, size_t *need)
1122 {
1123 	Elf32_Dyn dh32;
1124 	Elf64_Dyn dh64;
1125 	unsigned char *dbuf = CAST(unsigned char *, vbuf);
1126 
1127 	if (xdh_sizeof + offset > size) {
1128 		/*
1129 		 * We're out of note headers.
1130 		 */
1131 		return xdh_sizeof + offset;
1132 	}
1133 
1134 	memcpy(xdh_addr, &dbuf[offset], xdh_sizeof);
1135 	offset += xdh_sizeof;
1136 
1137 	switch (xdh_tag) {
1138 	case DT_FLAGS_1:
1139 		*pie = 1;
1140 		if (xdh_val & DF_1_PIE)
1141 			ms->mode |= 0111;
1142 		else
1143 			ms->mode &= ~0111;
1144 		break;
1145 	case DT_NEEDED:
1146 		(*need)++;
1147 		break;
1148 	default:
1149 		break;
1150 	}
1151 	return offset;
1152 }
1153 
1154 
1155 file_private size_t
donote(struct magic_set * ms,void * vbuf,size_t offset,size_t size,int clazz,int swap,size_t align,int * flags,uint16_t * notecount,int fd,off_t ph_off,int ph_num,off_t fsize)1156 donote(struct magic_set *ms, void *vbuf, size_t offset, size_t size,
1157     int clazz, int swap, size_t align, int *flags, uint16_t *notecount,
1158     int fd, off_t ph_off, int ph_num, off_t fsize)
1159 {
1160 	Elf32_Nhdr nh32;
1161 	Elf64_Nhdr nh64;
1162 	size_t noff, doff;
1163 	uint32_t namesz, descsz;
1164 	char buf[256];
1165 	unsigned char *nbuf = CAST(unsigned char *, vbuf);
1166 
1167 	if (*notecount == 0)
1168 		return 0;
1169 	--*notecount;
1170 
1171 	if (xnh_sizeof + offset > size) {
1172 		/*
1173 		 * We're out of note headers.
1174 		 */
1175 		return xnh_sizeof + offset;
1176 	}
1177 	/*XXX: GCC */
1178 	memset(&nh32, 0, sizeof(nh32));
1179 	memset(&nh64, 0, sizeof(nh64));
1180 
1181 	memcpy(xnh_addr, &nbuf[offset], xnh_sizeof);
1182 	offset += xnh_sizeof;
1183 
1184 	namesz = xnh_namesz;
1185 	descsz = xnh_descsz;
1186 
1187 	if ((namesz == 0) && (descsz == 0)) {
1188 		/*
1189 		 * We're out of note headers.
1190 		 */
1191 		return (offset >= size) ? offset : size;
1192 	}
1193 
1194 	if (namesz & 0x80000000) {
1195 	    (void)file_printf(ms, ", bad note name size %#lx",
1196 		CAST(unsigned long, namesz));
1197 	    return 0;
1198 	}
1199 
1200 	if (descsz & 0x80000000) {
1201 		(void)file_printf(ms, ", bad note description size %#lx",
1202 		    CAST(unsigned long, descsz));
1203 		return 0;
1204 	}
1205 
1206 	noff = offset;
1207 	doff = ELF_ALIGN(offset + namesz);
1208 
1209 	if (offset + namesz > size) {
1210 		/*
1211 		 * We're past the end of the buffer.
1212 		 */
1213 		return doff;
1214 	}
1215 
1216 	offset = ELF_ALIGN(doff + descsz);
1217 	if (doff + descsz > size) {
1218 		/*
1219 		 * We're past the end of the buffer.
1220 		 */
1221 		return (offset >= size) ? offset : size;
1222 	}
1223 
1224 
1225 	if ((*flags & FLAGS_DID_OS_NOTE) == 0) {
1226 		if (do_os_note(ms, nbuf, xnh_type, swap,
1227 		    namesz, descsz, noff, doff, flags))
1228 			return offset;
1229 	}
1230 
1231 	if ((*flags & FLAGS_DID_BUILD_ID) == 0) {
1232 		if (do_bid_note(ms, nbuf, xnh_type, swap,
1233 		    namesz, descsz, noff, doff, flags))
1234 			return offset;
1235 	}
1236 
1237 	if ((*flags & FLAGS_DID_NETBSD_PAX) == 0) {
1238 		if (do_pax_note(ms, nbuf, xnh_type, swap,
1239 		    namesz, descsz, noff, doff, flags))
1240 			return offset;
1241 	}
1242 
1243 	if ((*flags & FLAGS_DID_CORE) == 0) {
1244 		if (do_core_note(ms, nbuf, xnh_type, swap,
1245 		    namesz, descsz, noff, doff, flags, size, clazz))
1246 			return offset;
1247 	}
1248 
1249 	if ((*flags & FLAGS_DID_AUXV) == 0) {
1250 		if (do_auxv_note(ms, nbuf, xnh_type, swap,
1251 			namesz, descsz, noff, doff, flags, size, clazz,
1252 			fd, ph_off, ph_num, fsize))
1253 			return offset;
1254 	}
1255 
1256 	if (namesz == 7 && strcmp(RCAST(char *, &nbuf[noff]), "NetBSD") == 0) {
1257 		int descw, flag;
1258 		const char *str, *tag;
1259 		if (descsz > 100)
1260 			descsz = 100;
1261 		switch (xnh_type) {
1262 	    	case NT_NETBSD_VERSION:
1263 			return offset;
1264 		case NT_NETBSD_MARCH:
1265 			flag = FLAGS_DID_NETBSD_MARCH;
1266 			tag = "compiled for";
1267 			break;
1268 		case NT_NETBSD_CMODEL:
1269 			flag = FLAGS_DID_NETBSD_CMODEL;
1270 			tag = "compiler model";
1271 			break;
1272 		case NT_NETBSD_EMULATION:
1273 			flag = FLAGS_DID_NETBSD_EMULATION;
1274 			tag = "emulation:";
1275 			break;
1276 		default:
1277 			if (*flags & FLAGS_DID_NETBSD_UNKNOWN)
1278 				return offset;
1279 			*flags |= FLAGS_DID_NETBSD_UNKNOWN;
1280 			if (file_printf(ms, ", note=%u", xnh_type) == -1)
1281 				return offset;
1282 			return offset;
1283 		}
1284 
1285 		if (*flags & flag)
1286 			return offset;
1287 		str = RCAST(const char *, &nbuf[doff]);
1288 		descw = CAST(int, descsz);
1289 		*flags |= flag;
1290 		file_printf(ms, ", %s: %s", tag,
1291 		    file_copystr(buf, sizeof(buf), descw, str));
1292 		return offset;
1293 	}
1294 
1295 	return offset;
1296 }
1297 
1298 /* SunOS 5.x hardware capability descriptions */
1299 typedef struct cap_desc {
1300 	uint64_t cd_mask;
1301 	const char *cd_name;
1302 } cap_desc_t;
1303 
1304 static const cap_desc_t cap_desc_sparc[] = {
1305 	{ AV_SPARC_MUL32,		"MUL32" },
1306 	{ AV_SPARC_DIV32,		"DIV32" },
1307 	{ AV_SPARC_FSMULD,		"FSMULD" },
1308 	{ AV_SPARC_V8PLUS,		"V8PLUS" },
1309 	{ AV_SPARC_POPC,		"POPC" },
1310 	{ AV_SPARC_VIS,			"VIS" },
1311 	{ AV_SPARC_VIS2,		"VIS2" },
1312 	{ AV_SPARC_ASI_BLK_INIT,	"ASI_BLK_INIT" },
1313 	{ AV_SPARC_FMAF,		"FMAF" },
1314 	{ AV_SPARC_FJFMAU,		"FJFMAU" },
1315 	{ AV_SPARC_IMA,			"IMA" },
1316 	{ 0, NULL }
1317 };
1318 
1319 static const cap_desc_t cap_desc_386[] = {
1320 	{ AV_386_FPU,			"FPU" },
1321 	{ AV_386_TSC,			"TSC" },
1322 	{ AV_386_CX8,			"CX8" },
1323 	{ AV_386_SEP,			"SEP" },
1324 	{ AV_386_AMD_SYSC,		"AMD_SYSC" },
1325 	{ AV_386_CMOV,			"CMOV" },
1326 	{ AV_386_MMX,			"MMX" },
1327 	{ AV_386_AMD_MMX,		"AMD_MMX" },
1328 	{ AV_386_AMD_3DNow,		"AMD_3DNow" },
1329 	{ AV_386_AMD_3DNowx,		"AMD_3DNowx" },
1330 	{ AV_386_FXSR,			"FXSR" },
1331 	{ AV_386_SSE,			"SSE" },
1332 	{ AV_386_SSE2,			"SSE2" },
1333 	{ AV_386_PAUSE,			"PAUSE" },
1334 	{ AV_386_SSE3,			"SSE3" },
1335 	{ AV_386_MON,			"MON" },
1336 	{ AV_386_CX16,			"CX16" },
1337 	{ AV_386_AHF,			"AHF" },
1338 	{ AV_386_TSCP,			"TSCP" },
1339 	{ AV_386_AMD_SSE4A,		"AMD_SSE4A" },
1340 	{ AV_386_POPCNT,		"POPCNT" },
1341 	{ AV_386_AMD_LZCNT,		"AMD_LZCNT" },
1342 	{ AV_386_SSSE3,			"SSSE3" },
1343 	{ AV_386_SSE4_1,		"SSE4.1" },
1344 	{ AV_386_SSE4_2,		"SSE4.2" },
1345 	{ 0, NULL }
1346 };
1347 
1348 file_private int
doshn(struct magic_set * ms,int clazz,int swap,int fd,off_t off,int num,size_t size,off_t fsize,int mach,int strtab,int * flags,uint16_t * notecount)1349 doshn(struct magic_set *ms, int clazz, int swap, int fd, off_t off, int num,
1350     size_t size, off_t fsize, int mach, int strtab, int *flags,
1351     uint16_t *notecount)
1352 {
1353 	Elf32_Shdr sh32;
1354 	Elf64_Shdr sh64;
1355 	int stripped = 1, has_debug_info = 0;
1356 	size_t nbadcap = 0;
1357 	void *nbuf;
1358 	off_t noff, coff, name_off, offs;
1359 	uint64_t cap_hw1 = 0;	/* SunOS 5.x hardware capabilities */
1360 	uint64_t cap_sf1 = 0;	/* SunOS 5.x software capabilities */
1361 	char name[50];
1362 	ssize_t namesize;
1363 
1364 	if (ms->flags & MAGIC_MIME)
1365 		return 0;
1366 
1367 	if (num == 0) {
1368 		if (file_printf(ms, ", no section header") == -1)
1369 			return -1;
1370 		return 0;
1371 	}
1372 	if (size != xsh_sizeof) {
1373 		if (file_printf(ms, ", corrupted section header size") == -1)
1374 			return -1;
1375 		return 0;
1376 	}
1377 
1378 	/* Read offset of name section to be able to read section names later */
1379 	offs = CAST(off_t, (off + size * strtab));
1380 	if (pread(fd, xsh_addr, xsh_sizeof, offs) < CAST(ssize_t, xsh_sizeof)) {
1381 		if (file_printf(ms, ", missing section headers at %jd",
1382 		    (intmax_t)offs) == -1)
1383 			return -1;
1384 		return 0;
1385 	}
1386 	name_off = xsh_offset;
1387 
1388 	if (fsize != SIZE_UNKNOWN && fsize < name_off) {
1389 		if (file_printf(ms, ", too large section header offset %jd",
1390 		    (intmax_t)name_off) == -1)
1391 			return -1;
1392 		return 0;
1393 	}
1394 
1395 	for ( ; num; num--) {
1396 		/* Read the name of this section. */
1397 		offs = name_off + xsh_name;
1398 		if ((namesize = pread(fd, name, sizeof(name) - 1, offs))
1399 		    == -1) {
1400 			if (file_printf(ms,
1401 			    ", can't read name of elf section at %jd",
1402 			    (intmax_t)offs) == -1)
1403 				return -1;
1404 			return 0;
1405 		}
1406 		name[namesize] = '\0';
1407 		if (strcmp(name, ".debug_info") == 0) {
1408 			has_debug_info = 1;
1409 			stripped = 0;
1410 		}
1411 
1412 		if (pread(fd, xsh_addr, xsh_sizeof, off) <
1413 		    CAST(ssize_t, xsh_sizeof)) {
1414 			if (file_printf(ms, ", can't read elf section at %jd",
1415 			    (intmax_t)off) == -1)
1416 				return -1;
1417 			return 0;
1418 		}
1419 		off += size;
1420 
1421 		/* Things we can determine before we seek */
1422 		switch (xsh_type) {
1423 		case SHT_SYMTAB:
1424 #if 0
1425 		case SHT_DYNSYM:
1426 #endif
1427 			stripped = 0;
1428 			break;
1429 		default:
1430 			if (fsize != SIZE_UNKNOWN && xsh_offset > fsize) {
1431 				/* Perhaps warn here */
1432 				continue;
1433 			}
1434 			break;
1435 		}
1436 
1437 
1438 		/* Things we can determine when we seek */
1439 		switch (xsh_type) {
1440 		case SHT_NOTE:
1441 			if (CAST(uintmax_t, (xsh_size + xsh_offset)) >
1442 			    CAST(uintmax_t, fsize)) {
1443 				if (file_printf(ms,
1444 				    ", note offset/size %#" INTMAX_T_FORMAT
1445 				    "x+%#" INTMAX_T_FORMAT "x exceeds"
1446 				    " file size %#" INTMAX_T_FORMAT "x",
1447 				    CAST(uintmax_t, xsh_offset),
1448 				    CAST(uintmax_t, xsh_size),
1449 				    CAST(uintmax_t, fsize)) == -1)
1450 					return -1;
1451 				return 0;
1452 			}
1453 			if (xsh_size > ms->elf_shsize_max) {
1454 				file_error(ms, errno, "Note section size too "
1455 				    "big (%ju > %zu)", (uintmax_t)xsh_size,
1456 				    ms->elf_shsize_max);
1457 				return -1;
1458 			}
1459 			if ((nbuf = malloc(xsh_size)) == NULL) {
1460 				file_error(ms, errno, "Cannot allocate memory"
1461 				    " for note");
1462 				return -1;
1463 			}
1464 			offs = xsh_offset;
1465 			if (pread(fd, nbuf, xsh_size, offs) <
1466 			    CAST(ssize_t, xsh_size)) {
1467 				free(nbuf);
1468 				if (file_printf(ms,
1469 				    ", can't read elf note at %jd",
1470 				    (intmax_t)offs) == -1)
1471 					return -1;
1472 				return 0;
1473 			}
1474 
1475 			noff = 0;
1476 			for (;;) {
1477 				if (noff >= CAST(off_t, xsh_size))
1478 					break;
1479 				noff = donote(ms, nbuf, CAST(size_t, noff),
1480 				    xsh_size, clazz, swap, 4, flags, notecount,
1481 				    fd, 0, 0, 0);
1482 				if (noff == 0)
1483 					break;
1484 			}
1485 			free(nbuf);
1486 			break;
1487 		case SHT_SUNW_cap:
1488 			switch (mach) {
1489 			case EM_SPARC:
1490 			case EM_SPARCV9:
1491 			case EM_IA_64:
1492 			case EM_386:
1493 			case EM_AMD64:
1494 				break;
1495 			default:
1496 				goto skip;
1497 			}
1498 
1499 			if (nbadcap > 5)
1500 				break;
1501 			if (lseek(fd, xsh_offset, SEEK_SET)
1502 			    == CAST(off_t, -1)) {
1503 				file_badseek(ms);
1504 				return -1;
1505 			}
1506 			coff = 0;
1507 			for (;;) {
1508 				Elf32_Cap cap32;
1509 				Elf64_Cap cap64;
1510 				char cbuf[/*CONSTCOND*/
1511 				    MAX(sizeof(cap32), sizeof(cap64))];
1512 				if ((coff += xcap_sizeof) >
1513 				    CAST(off_t, xsh_size))
1514 					break;
1515 				if (read(fd, cbuf, CAST(size_t, xcap_sizeof)) !=
1516 				    CAST(ssize_t, xcap_sizeof)) {
1517 					file_badread(ms);
1518 					return -1;
1519 				}
1520 				if (cbuf[0] == 'A') {
1521 #ifdef notyet
1522 					char *p = cbuf + 1;
1523 					uint32_t len, tag;
1524 					memcpy(&len, p, sizeof(len));
1525 					p += 4;
1526 					len = getu32(swap, len);
1527 					if (memcmp("gnu", p, 3) != 0) {
1528 					    if (file_printf(ms,
1529 						", unknown capability %.3s", p)
1530 						== -1)
1531 						return -1;
1532 					    break;
1533 					}
1534 					p += strlen(p) + 1;
1535 					tag = *p++;
1536 					memcpy(&len, p, sizeof(len));
1537 					p += 4;
1538 					len = getu32(swap, len);
1539 					if (tag != 1) {
1540 					    if (file_printf(ms, ", unknown gnu"
1541 						" capability tag %d", tag)
1542 						== -1)
1543 						return -1;
1544 					    break;
1545 					}
1546 					// gnu attributes
1547 #endif
1548 					break;
1549 				}
1550 				memcpy(xcap_addr, cbuf, xcap_sizeof);
1551 				switch (xcap_tag) {
1552 				case CA_SUNW_NULL:
1553 					break;
1554 				case CA_SUNW_HW_1:
1555 					cap_hw1 |= xcap_val;
1556 					break;
1557 				case CA_SUNW_SF_1:
1558 					cap_sf1 |= xcap_val;
1559 					break;
1560 				default:
1561 					if (file_printf(ms,
1562 					    ", with unknown capability "
1563 					    "%#" INT64_T_FORMAT "x = %#"
1564 					    INT64_T_FORMAT "x",
1565 					    CAST(unsigned long long, xcap_tag),
1566 					    CAST(unsigned long long, xcap_val))
1567 					    == -1)
1568 						return -1;
1569 					if (nbadcap++ > 2)
1570 						coff = xsh_size;
1571 					break;
1572 				}
1573 			}
1574 			/*FALLTHROUGH*/
1575 		skip:
1576 		default:
1577 			break;
1578 		}
1579 	}
1580 
1581 	if (has_debug_info) {
1582 		if (file_printf(ms, ", with debug_info") == -1)
1583 			return -1;
1584 	}
1585 	if (file_printf(ms, ", %sstripped", stripped ? "" : "not ") == -1)
1586 		return -1;
1587 	if (cap_hw1) {
1588 		const cap_desc_t *cdp;
1589 		switch (mach) {
1590 		case EM_SPARC:
1591 		case EM_SPARC32PLUS:
1592 		case EM_SPARCV9:
1593 			cdp = cap_desc_sparc;
1594 			break;
1595 		case EM_386:
1596 		case EM_IA_64:
1597 		case EM_AMD64:
1598 			cdp = cap_desc_386;
1599 			break;
1600 		default:
1601 			cdp = NULL;
1602 			break;
1603 		}
1604 		if (file_printf(ms, ", uses") == -1)
1605 			return -1;
1606 		if (cdp) {
1607 			while (cdp->cd_name) {
1608 				if (cap_hw1 & cdp->cd_mask) {
1609 					if (file_printf(ms,
1610 					    " %s", cdp->cd_name) == -1)
1611 						return -1;
1612 					cap_hw1 &= ~cdp->cd_mask;
1613 				}
1614 				++cdp;
1615 			}
1616 			if (cap_hw1)
1617 				if (file_printf(ms,
1618 				    " unknown hardware capability %#"
1619 				    INT64_T_FORMAT "x",
1620 				    CAST(unsigned long long, cap_hw1)) == -1)
1621 					return -1;
1622 		} else {
1623 			if (file_printf(ms,
1624 			    " hardware capability %#" INT64_T_FORMAT "x",
1625 			    CAST(unsigned long long, cap_hw1)) == -1)
1626 				return -1;
1627 		}
1628 	}
1629 	if (cap_sf1) {
1630 		if (cap_sf1 & SF1_SUNW_FPUSED) {
1631 			if (file_printf(ms,
1632 			    (cap_sf1 & SF1_SUNW_FPKNWN)
1633 			    ? ", uses frame pointer"
1634 			    : ", not known to use frame pointer") == -1)
1635 				return -1;
1636 		}
1637 		cap_sf1 &= ~SF1_SUNW_MASK;
1638 		if (cap_sf1)
1639 			if (file_printf(ms,
1640 			    ", with unknown software capability %#"
1641 			    INT64_T_FORMAT "x",
1642 			    CAST(unsigned long long, cap_sf1)) == -1)
1643 				return -1;
1644 	}
1645 	return 0;
1646 }
1647 
1648 /*
1649  * Look through the program headers of an executable image, to determine
1650  * if it is statically or dynamically linked. If it has a dynamic section,
1651  * it is pie, and does not have an interpreter or needed libraries, we
1652  * call it static pie.
1653  */
1654 file_private int
dophn_exec(struct magic_set * ms,int clazz,int swap,int fd,off_t off,int num,size_t size,off_t fsize,int sh_num,int * flags,uint16_t * notecount)1655 dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
1656     int num, size_t size, off_t fsize, int sh_num, int *flags,
1657     uint16_t *notecount)
1658 {
1659 	Elf32_Phdr ph32;
1660 	Elf64_Phdr ph64;
1661 	const char *linking_style;
1662 	unsigned char nbuf[BUFSIZ];
1663 	char ibuf[BUFSIZ];
1664 	char interp[BUFSIZ];
1665 	ssize_t bufsize;
1666 	size_t offset, align, need = 0;
1667 	int pie = 0, dynamic = 0;
1668 
1669 	if (num == 0) {
1670 		if (file_printf(ms, ", no program header") == -1)
1671 			return -1;
1672 		return 0;
1673 	}
1674 	if (size != xph_sizeof) {
1675 		if (file_printf(ms, ", corrupted program header size") == -1)
1676 			return -1;
1677 		return 0;
1678 	}
1679 
1680 	interp[0] = '\0';
1681   	for ( ; num; num--) {
1682 		int doread;
1683 		if (pread(fd, xph_addr, xph_sizeof, off) <
1684 		    CAST(ssize_t, xph_sizeof)) {
1685 			if (file_printf(ms,
1686 			    ", can't read elf program headers at %jd",
1687 			    (intmax_t)off) == -1)
1688 				return -1;
1689 			return 0;
1690 		}
1691 
1692 		off += size;
1693 		bufsize = 0;
1694 		align = 4;
1695 
1696 		/* Things we can determine before we seek */
1697 		switch (xph_type) {
1698 		case PT_DYNAMIC:
1699 			doread = 1;
1700 			break;
1701 		case PT_NOTE:
1702 			if (sh_num)	/* Did this through section headers */
1703 				continue;
1704 			if (((align = xph_align) & 0x80000000UL) != 0 ||
1705 			    align < 4) {
1706 				if (file_printf(ms,
1707 				    ", invalid note alignment %#lx",
1708 				    CAST(unsigned long, align)) == -1)
1709 					return -1;
1710 				align = 4;
1711 			}
1712 			/*FALLTHROUGH*/
1713 		case PT_INTERP:
1714 			doread = 1;
1715 			break;
1716 		default:
1717 			doread = 0;
1718 			if (fsize != SIZE_UNKNOWN && xph_offset > fsize) {
1719 				/* Maybe warn here? */
1720 				continue;
1721 			}
1722 			break;
1723 		}
1724 
1725 		if (doread) {
1726 			size_t len = xph_filesz < sizeof(nbuf) ? xph_filesz
1727 			    : sizeof(nbuf);
1728 			off_t offs = xph_offset;
1729 			bufsize = pread(fd, nbuf, len, offs);
1730 			if (bufsize == -1) {
1731 				if (file_printf(ms,
1732 				    ", can't read section at %jd",
1733 				    (intmax_t)offs) == -1)
1734 					return -1;
1735 				return 0;
1736 			}
1737 		}
1738 
1739 		/* Things we can determine when we seek */
1740 		switch (xph_type) {
1741 		case PT_DYNAMIC:
1742 			dynamic = 1;
1743 			offset = 0;
1744 			// Let DF_1 determine if we are PIE or not.
1745 			ms->mode &= ~0111;
1746 			for (;;) {
1747 				if (offset >= CAST(size_t, bufsize))
1748 					break;
1749 				offset = dodynamic(ms, nbuf, offset,
1750 				    CAST(size_t, bufsize), clazz, swap,
1751 				    &pie, &need);
1752 				if (offset == 0)
1753 					break;
1754 			}
1755 			if (ms->flags & MAGIC_MIME)
1756 				continue;
1757 			break;
1758 
1759 		case PT_INTERP:
1760 			need++;
1761 			if (ms->flags & MAGIC_MIME)
1762 				continue;
1763 			if (bufsize && nbuf[0]) {
1764 				nbuf[bufsize - 1] = '\0';
1765 				memcpy(interp, nbuf, CAST(size_t, bufsize));
1766 			} else
1767 				strlcpy(interp, "*empty*", sizeof(interp));
1768 			break;
1769 		case PT_NOTE:
1770 			if (ms->flags & MAGIC_MIME)
1771 				return 0;
1772 			/*
1773 			 * This is a PT_NOTE section; loop through all the notes
1774 			 * in the section.
1775 			 */
1776 			offset = 0;
1777 			for (;;) {
1778 				if (offset >= CAST(size_t, bufsize))
1779 					break;
1780 				offset = donote(ms, nbuf, offset,
1781 				    CAST(size_t, bufsize), clazz, swap, align,
1782 				    flags, notecount, fd, 0, 0, 0);
1783 				if (offset == 0)
1784 					break;
1785 			}
1786 			break;
1787 		default:
1788 			if (ms->flags & MAGIC_MIME)
1789 				continue;
1790 			break;
1791 		}
1792 	}
1793 	if (ms->flags & MAGIC_MIME)
1794 		return 0;
1795 	if (dynamic) {
1796 		if (pie && need == 0)
1797 			linking_style = "static-pie";
1798 		else
1799 			linking_style = "dynamically";
1800 	} else {
1801 		linking_style = "statically";
1802 	}
1803 	if (file_printf(ms, ", %s linked", linking_style) == -1)
1804 		return -1;
1805 	if (interp[0])
1806 		if (file_printf(ms, ", interpreter %s", file_printable(ms,
1807 		    ibuf, sizeof(ibuf), interp, sizeof(interp))) == -1)
1808 			return -1;
1809 	return 0;
1810 }
1811 
1812 
1813 file_protected int
file_tryelf(struct magic_set * ms,const struct buffer * b)1814 file_tryelf(struct magic_set *ms, const struct buffer *b)
1815 {
1816 	int fd = b->fd;
1817 	const unsigned char *buf = CAST(const unsigned char *, b->fbuf);
1818 	size_t nbytes = b->flen;
1819 	union {
1820 		int32_t l;
1821 		char c[sizeof(int32_t)];
1822 	} u;
1823 	int clazz;
1824 	int swap;
1825 	struct stat st;
1826 	const struct stat *stp;
1827 	off_t fsize;
1828 	int flags = 0;
1829 	Elf32_Ehdr elf32hdr;
1830 	Elf64_Ehdr elf64hdr;
1831 	uint16_t type, phnum, shnum, notecount;
1832 
1833 	if (ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION))
1834 		return 0;
1835 	/*
1836 	 * ELF executables have multiple section headers in arbitrary
1837 	 * file locations and thus file(1) cannot determine it from easily.
1838 	 * Instead we traverse thru all section headers until a symbol table
1839 	 * one is found or else the binary is stripped.
1840 	 * Return immediately if it's not ELF (so we avoid pipe2file unless
1841 	 * needed).
1842 	 */
1843 	if (buf[EI_MAG0] != ELFMAG0
1844 	    || (buf[EI_MAG1] != ELFMAG1 && buf[EI_MAG1] != OLFMAG1)
1845 	    || buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
1846 		return 0;
1847 
1848 	/*
1849 	 * If we cannot seek, it must be a pipe, socket or fifo.
1850 	 */
1851 	if((lseek(fd, CAST(off_t, 0), SEEK_SET) == CAST(off_t, -1))
1852 	    && (errno == ESPIPE))
1853 		fd = file_pipe2file(ms, fd, buf, nbytes);
1854 
1855 	if (fd == -1) {
1856 		file_badread(ms);
1857 		return -1;
1858 	}
1859 
1860 	stp = &b->st;
1861 	/*
1862 	 * b->st.st_size != 0 if previous fstat() succeeded,
1863 	 * which is likely, we can avoid extra stat() call.
1864 	 */
1865 	if (b->st.st_size == 0) {
1866 		stp = &st;
1867 		if (fstat(fd, &st) == -1) {
1868 			file_badread(ms);
1869 			return -1;
1870 		}
1871 	}
1872 	if (S_ISREG(stp->st_mode) || stp->st_size != 0)
1873 		fsize = stp->st_size;
1874 	else
1875 		fsize = SIZE_UNKNOWN;
1876 
1877 	clazz = buf[EI_CLASS];
1878 
1879 	switch (clazz) {
1880 	case ELFCLASS32:
1881 #undef elf_getu
1882 #define elf_getu(a, b)	elf_getu32(a, b)
1883 #undef elfhdr
1884 #define elfhdr elf32hdr
1885 #include "elfclass.h"
1886 	case ELFCLASS64:
1887 #undef elf_getu
1888 #define elf_getu(a, b)	elf_getu64(a, b)
1889 #undef elfhdr
1890 #define elfhdr elf64hdr
1891 #include "elfclass.h"
1892 	default:
1893 	    if (file_printf(ms, ", unknown class %d", clazz) == -1)
1894 		    return -1;
1895 	    break;
1896 	}
1897 	return 0;
1898 }
1899 #endif
1900