1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1998 John D. Polstra
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/param.h>
30#include <sys/endian.h>
31#include <sys/mman.h>
32#include <sys/stat.h>
33
34#include <ctype.h>
35#include <dirent.h>
36#include <elf-hints.h>
37#include <err.h>
38#include <errno.h>
39#include <fcntl.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43#include <unistd.h>
44
45#include "ldconfig.h"
46
47#define MAXDIRS		1024		/* Maximum directories in path */
48#define MAXFILESIZE	(16*1024)	/* Maximum hints file size */
49
50static void	add_dir(const char *, const char *, bool);
51static void	read_dirs_from_file(const char *, const char *);
52static void	read_elf_hints(const char *, bool, bool);
53static void	write_elf_hints(const char *);
54
55static const char	*dirs[MAXDIRS];
56static int		 ndirs;
57static bool		 is_be;
58bool			 insecure;
59
60static void
61add_dir(const char *hintsfile, const char *name, bool trusted)
62{
63	struct stat 	stbuf;
64	int		i;
65
66	/* Do some security checks */
67	if (!trusted && !insecure) {
68		if (stat(name, &stbuf) == -1) {
69			warn("%s", name);
70			return;
71		}
72		if (stbuf.st_uid != 0) {
73			warnx("%s: ignoring directory not owned by root", name);
74			return;
75		}
76		if ((stbuf.st_mode & S_IWOTH) != 0) {
77			warnx("%s: ignoring world-writable directory", name);
78			return;
79		}
80		if ((stbuf.st_mode & S_IWGRP) != 0) {
81			warnx("%s: ignoring group-writable directory", name);
82			return;
83		}
84	}
85
86	for (i = 0;  i < ndirs;  i++)
87		if (strcmp(dirs[i], name) == 0)
88			return;
89	if (ndirs >= MAXDIRS)
90		errx(1, "\"%s\": Too many directories in path", hintsfile);
91	dirs[ndirs++] = name;
92}
93
94void
95list_elf_hints(const char *hintsfile)
96{
97	int	i;
98	int	nlibs;
99
100	read_elf_hints(hintsfile, true, false);
101	printf("%s:\n", hintsfile);
102	printf("\tsearch directories:");
103	for (i = 0;  i < ndirs;  i++)
104		printf("%c%s", i == 0 ? ' ' : ':', dirs[i]);
105	printf("\n");
106
107	nlibs = 0;
108	for (i = 0;  i < ndirs;  i++) {
109		DIR		*dirp;
110		struct dirent	*dp;
111
112		if ((dirp = opendir(dirs[i])) == NULL)
113			continue;
114		while ((dp = readdir(dirp)) != NULL) {
115			int		 len;
116			int		 namelen;
117			const char	*name;
118			const char	*vers;
119
120			/* Name can't be shorter than "libx.so.0" */
121			if ((len = strlen(dp->d_name)) < 9 ||
122			    strncmp(dp->d_name, "lib", 3) != 0)
123				continue;
124			name = dp->d_name + 3;
125			vers = dp->d_name + len;
126			while (vers > dp->d_name && isdigit(*(vers-1)))
127				vers--;
128			if (vers == dp->d_name + len)
129				continue;
130			if (vers < dp->d_name + 4 ||
131			    strncmp(vers - 4, ".so.", 4) != 0)
132				continue;
133
134			/* We have a valid shared library name. */
135			namelen = (vers - 4) - name;
136			printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs,
137			    namelen, name, vers, dirs[i], dp->d_name);
138			nlibs++;
139		}
140		closedir(dirp);
141	}
142}
143
144static void
145read_dirs_from_file(const char *hintsfile, const char *listfile)
146{
147	FILE	*fp;
148	char	 buf[MAXPATHLEN];
149	int	 linenum;
150
151	if ((fp = fopen(listfile, "r")) == NULL)
152		err(1, "%s", listfile);
153
154	linenum = 0;
155	while (fgets(buf, sizeof buf, fp) != NULL) {
156		char	*cp, *sp;
157
158		linenum++;
159		cp = buf;
160		/* Skip leading white space. */
161		while (isspace(*cp))
162			cp++;
163		if (*cp == '#' || *cp == '\0')
164			continue;
165		sp = cp;
166		/* Advance over the directory name. */
167		while (!isspace(*cp) && *cp != '\0')
168			cp++;
169		/* Terminate the string and skip trailing white space. */
170		if (*cp != '\0') {
171			*cp++ = '\0';
172			while (isspace(*cp))
173				cp++;
174		}
175		/* Now we had better be at the end of the line. */
176		if (*cp != '\0')
177			warnx("%s:%d: trailing characters ignored",
178			    listfile, linenum);
179
180		if ((sp = strdup(sp)) == NULL)
181			errx(1, "Out of memory");
182		add_dir(hintsfile, sp, 0);
183	}
184
185	fclose(fp);
186}
187
188/* Convert between native byte order and forced little resp. big endian. */
189#define COND_SWAP(n) (is_be ? be32toh(n) : le32toh(n))
190
191static void
192read_elf_hints(const char *hintsfile, bool must_exist, bool force_be)
193{
194	int	 		 fd;
195	struct stat		 s;
196	void			*mapbase;
197	struct elfhints_hdr	*hdr;
198	char			*strtab;
199	char			*dirlist;
200	char			*p;
201	int			 hdr_version;
202
203	if ((fd = open(hintsfile, O_RDONLY)) == -1) {
204		if (errno == ENOENT && !must_exist)
205			return;
206		err(1, "Cannot open \"%s\"", hintsfile);
207	}
208	if (fstat(fd, &s) == -1)
209		err(1, "Cannot stat \"%s\"", hintsfile);
210	if (s.st_size > MAXFILESIZE)
211		errx(1, "\"%s\" is unreasonably large", hintsfile);
212	/*
213	 * We use a read-write, private mapping so that we can null-terminate
214	 * some strings in it without affecting the underlying file.
215	 */
216	mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE,
217	    MAP_PRIVATE, fd, 0);
218	if (mapbase == MAP_FAILED)
219		err(1, "Cannot mmap \"%s\"", hintsfile);
220	close(fd);
221
222	hdr = (struct elfhints_hdr *)mapbase;
223	is_be = hdr->magic == htobe32(ELFHINTS_MAGIC);
224	if (COND_SWAP(hdr->magic) != ELFHINTS_MAGIC)
225		errx(1, "\"%s\": invalid file format", hintsfile);
226	if (force_be && !is_be)
227		errx(1, "\"%s\": incompatible endianness requested", hintsfile);
228	hdr_version = COND_SWAP(hdr->version);
229	if (hdr_version != 1)
230		errx(1, "\"%s\": unrecognized file version (%d)", hintsfile,
231		    hdr_version);
232
233	strtab = (char *)mapbase + COND_SWAP(hdr->strtab);
234	dirlist = strtab + COND_SWAP(hdr->dirlist);
235
236	if (*dirlist != '\0')
237		while ((p = strsep(&dirlist, ":")) != NULL)
238			add_dir(hintsfile, p, 1);
239}
240
241void
242update_elf_hints(const char *hintsfile, int argc, char **argv, bool merge,
243    bool force_be)
244{
245	struct stat s;
246	int i;
247
248	/*
249	 * Create little-endian hints files on all architectures unless
250	 * ldconfig has been invoked with the -B option.
251	 */
252	is_be = force_be;
253	if (merge)
254		read_elf_hints(hintsfile, false, force_be);
255	for (i = 0;  i < argc;  i++) {
256		if (stat(argv[i], &s) == -1)
257			warn("warning: %s", argv[i]);
258		else if (S_ISREG(s.st_mode))
259			read_dirs_from_file(hintsfile, argv[i]);
260		else
261			add_dir(hintsfile, argv[i], 0);
262	}
263	write_elf_hints(hintsfile);
264}
265
266static void
267write_elf_hints(const char *hintsfile)
268{
269	struct elfhints_hdr	 hdr;
270	char			*tempname;
271	int			 fd;
272	FILE			*fp;
273	int			 i;
274
275	if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1)
276		errx(1, "Out of memory");
277	if ((fd = mkstemp(tempname)) ==  -1)
278		err(1, "mkstemp(%s)", tempname);
279	if (fchmod(fd, 0444) == -1)
280		err(1, "fchmod(%s)", tempname);
281	if ((fp = fdopen(fd, "wb")) == NULL)
282		err(1, "fdopen(%s)", tempname);
283
284	hdr.magic = COND_SWAP(ELFHINTS_MAGIC);
285	hdr.version = COND_SWAP(1);
286	hdr.strtab = COND_SWAP(sizeof hdr);
287	hdr.strsize = 0;
288	hdr.dirlist = 0;
289	memset(hdr.spare, 0, sizeof hdr.spare);
290
291	/* Count up the size of the string table. */
292	if (ndirs > 0) {
293		hdr.strsize += strlen(dirs[0]);
294		for (i = 1;  i < ndirs;  i++)
295			hdr.strsize += 1 + strlen(dirs[i]);
296	}
297	hdr.dirlistlen = COND_SWAP(hdr.strsize);
298	hdr.strsize++;	/* For the null terminator */
299	/* convert in-place from native to target endianness */
300	hdr.strsize = COND_SWAP(hdr.strsize);
301
302	/* Write the header. */
303	if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr)
304		err(1, "%s: write error", tempname);
305	/* Write the strings. */
306	if (ndirs > 0) {
307		if (fputs(dirs[0], fp) == EOF)
308			err(1, "%s: write error", tempname);
309		for (i = 1;  i < ndirs;  i++)
310			if (fprintf(fp, ":%s", dirs[i]) < 0)
311				err(1, "%s: write error", tempname);
312	}
313	if (putc('\0', fp) == EOF || fclose(fp) == EOF)
314		err(1, "%s: write error", tempname);
315
316	if (rename(tempname, hintsfile) == -1)
317		err(1, "rename %s to %s", tempname, hintsfile);
318	free(tempname);
319}
320