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/mman.h> 31 #include <sys/stat.h> 32 33 #include <ctype.h> 34 #include <dirent.h> 35 #include <elf-hints.h> 36 #include <err.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #include "ldconfig.h" 45 46 #define MAXDIRS 1024 /* Maximum directories in path */ 47 #define MAXFILESIZE (16*1024) /* Maximum hints file size */ 48 49 static void add_dir(const char *, const char *, bool); 50 static void read_dirs_from_file(const char *, const char *); 51 static void read_elf_hints(const char *, bool); 52 static void write_elf_hints(const char *); 53 54 static const char *dirs[MAXDIRS]; 55 static int ndirs; 56 bool insecure; 57 58 static void 59 add_dir(const char *hintsfile, const char *name, bool trusted) 60 { 61 struct stat stbuf; 62 int i; 63 64 /* Do some security checks */ 65 if (!trusted && !insecure) { 66 if (stat(name, &stbuf) == -1) { 67 warn("%s", name); 68 return; 69 } 70 if (stbuf.st_uid != 0) { 71 warnx("%s: ignoring directory not owned by root", name); 72 return; 73 } 74 if ((stbuf.st_mode & S_IWOTH) != 0) { 75 warnx("%s: ignoring world-writable directory", name); 76 return; 77 } 78 if ((stbuf.st_mode & S_IWGRP) != 0) { 79 warnx("%s: ignoring group-writable directory", name); 80 return; 81 } 82 } 83 84 for (i = 0; i < ndirs; i++) 85 if (strcmp(dirs[i], name) == 0) 86 return; 87 if (ndirs >= MAXDIRS) 88 errx(1, "\"%s\": Too many directories in path", hintsfile); 89 dirs[ndirs++] = name; 90 } 91 92 void 93 list_elf_hints(const char *hintsfile) 94 { 95 int i; 96 int nlibs; 97 98 read_elf_hints(hintsfile, 1); 99 printf("%s:\n", hintsfile); 100 printf("\tsearch directories:"); 101 for (i = 0; i < ndirs; i++) 102 printf("%c%s", i == 0 ? ' ' : ':', dirs[i]); 103 printf("\n"); 104 105 nlibs = 0; 106 for (i = 0; i < ndirs; i++) { 107 DIR *dirp; 108 struct dirent *dp; 109 110 if ((dirp = opendir(dirs[i])) == NULL) 111 continue; 112 while ((dp = readdir(dirp)) != NULL) { 113 int len; 114 int namelen; 115 const char *name; 116 const char *vers; 117 118 /* Name can't be shorter than "libx.so.0" */ 119 if ((len = strlen(dp->d_name)) < 9 || 120 strncmp(dp->d_name, "lib", 3) != 0) 121 continue; 122 name = dp->d_name + 3; 123 vers = dp->d_name + len; 124 while (vers > dp->d_name && isdigit(*(vers-1))) 125 vers--; 126 if (vers == dp->d_name + len) 127 continue; 128 if (vers < dp->d_name + 4 || 129 strncmp(vers - 4, ".so.", 4) != 0) 130 continue; 131 132 /* We have a valid shared library name. */ 133 namelen = (vers - 4) - name; 134 printf("\t%d:-l%.*s.%s => %s/%s\n", nlibs, 135 namelen, name, vers, dirs[i], dp->d_name); 136 nlibs++; 137 } 138 closedir(dirp); 139 } 140 } 141 142 static void 143 read_dirs_from_file(const char *hintsfile, const char *listfile) 144 { 145 FILE *fp; 146 char buf[MAXPATHLEN]; 147 int linenum; 148 149 if ((fp = fopen(listfile, "r")) == NULL) 150 err(1, "%s", listfile); 151 152 linenum = 0; 153 while (fgets(buf, sizeof buf, fp) != NULL) { 154 char *cp, *sp; 155 156 linenum++; 157 cp = buf; 158 /* Skip leading white space. */ 159 while (isspace(*cp)) 160 cp++; 161 if (*cp == '#' || *cp == '\0') 162 continue; 163 sp = cp; 164 /* Advance over the directory name. */ 165 while (!isspace(*cp) && *cp != '\0') 166 cp++; 167 /* Terminate the string and skip trailing white space. */ 168 if (*cp != '\0') { 169 *cp++ = '\0'; 170 while (isspace(*cp)) 171 cp++; 172 } 173 /* Now we had better be at the end of the line. */ 174 if (*cp != '\0') 175 warnx("%s:%d: trailing characters ignored", 176 listfile, linenum); 177 178 if ((sp = strdup(sp)) == NULL) 179 errx(1, "Out of memory"); 180 add_dir(hintsfile, sp, 0); 181 } 182 183 fclose(fp); 184 } 185 186 static void 187 read_elf_hints(const char *hintsfile, bool must_exist) 188 { 189 int fd; 190 struct stat s; 191 void *mapbase; 192 struct elfhints_hdr *hdr; 193 char *strtab; 194 char *dirlist; 195 char *p; 196 197 if ((fd = open(hintsfile, O_RDONLY)) == -1) { 198 if (errno == ENOENT && !must_exist) 199 return; 200 err(1, "Cannot open \"%s\"", hintsfile); 201 } 202 if (fstat(fd, &s) == -1) 203 err(1, "Cannot stat \"%s\"", hintsfile); 204 if (s.st_size > MAXFILESIZE) 205 errx(1, "\"%s\" is unreasonably large", hintsfile); 206 /* 207 * We use a read-write, private mapping so that we can null-terminate 208 * some strings in it without affecting the underlying file. 209 */ 210 mapbase = mmap(NULL, s.st_size, PROT_READ|PROT_WRITE, 211 MAP_PRIVATE, fd, 0); 212 if (mapbase == MAP_FAILED) 213 err(1, "Cannot mmap \"%s\"", hintsfile); 214 close(fd); 215 216 hdr = (struct elfhints_hdr *)mapbase; 217 if (hdr->magic != ELFHINTS_MAGIC) 218 errx(1, "\"%s\": invalid file format", hintsfile); 219 if (hdr->version != 1) 220 errx(1, "\"%s\": unrecognized file version (%d)", hintsfile, 221 hdr->version); 222 223 strtab = (char *)mapbase + hdr->strtab; 224 dirlist = strtab + hdr->dirlist; 225 226 if (*dirlist != '\0') 227 while ((p = strsep(&dirlist, ":")) != NULL) 228 add_dir(hintsfile, p, 1); 229 } 230 231 void 232 update_elf_hints(const char *hintsfile, int argc, char **argv, bool merge) 233 { 234 struct stat s; 235 int i; 236 237 if (merge) 238 read_elf_hints(hintsfile, false); 239 for (i = 0; i < argc; i++) { 240 if (stat(argv[i], &s) == -1) 241 warn("warning: %s", argv[i]); 242 else if (S_ISREG(s.st_mode)) 243 read_dirs_from_file(hintsfile, argv[i]); 244 else 245 add_dir(hintsfile, argv[i], 0); 246 } 247 write_elf_hints(hintsfile); 248 } 249 250 static void 251 write_elf_hints(const char *hintsfile) 252 { 253 struct elfhints_hdr hdr; 254 char *tempname; 255 int fd; 256 FILE *fp; 257 int i; 258 259 if (asprintf(&tempname, "%s.XXXXXX", hintsfile) == -1) 260 errx(1, "Out of memory"); 261 if ((fd = mkstemp(tempname)) == -1) 262 err(1, "mkstemp(%s)", tempname); 263 if (fchmod(fd, 0444) == -1) 264 err(1, "fchmod(%s)", tempname); 265 if ((fp = fdopen(fd, "wb")) == NULL) 266 err(1, "fdopen(%s)", tempname); 267 268 hdr.magic = ELFHINTS_MAGIC; 269 hdr.version = 1; 270 hdr.strtab = sizeof hdr; 271 hdr.strsize = 0; 272 hdr.dirlist = 0; 273 memset(hdr.spare, 0, sizeof hdr.spare); 274 275 /* Count up the size of the string table. */ 276 if (ndirs > 0) { 277 hdr.strsize += strlen(dirs[0]); 278 for (i = 1; i < ndirs; i++) 279 hdr.strsize += 1 + strlen(dirs[i]); 280 } 281 hdr.dirlistlen = hdr.strsize; 282 hdr.strsize++; /* For the null terminator */ 283 284 /* Write the header. */ 285 if (fwrite(&hdr, 1, sizeof hdr, fp) != sizeof hdr) 286 err(1, "%s: write error", tempname); 287 /* Write the strings. */ 288 if (ndirs > 0) { 289 if (fputs(dirs[0], fp) == EOF) 290 err(1, "%s: write error", tempname); 291 for (i = 1; i < ndirs; i++) 292 if (fprintf(fp, ":%s", dirs[i]) < 0) 293 err(1, "%s: write error", tempname); 294 } 295 if (putc('\0', fp) == EOF || fclose(fp) == EOF) 296 err(1, "%s: write error", tempname); 297 298 if (rename(tempname, hintsfile) == -1) 299 err(1, "rename %s to %s", tempname, hintsfile); 300 free(tempname); 301 } 302