1 /* $OpenBSD: sod.c,v 1.33 2015/10/29 13:07:41 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1993 Paul Kranenburg 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 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Paul Kranenburg. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 * 32 */ 33 34 #include <sys/types.h> 35 #include <sys/mman.h> 36 #include <machine/exec.h> 37 #include <limits.h> 38 #include <stdio.h> 39 #include <fcntl.h> 40 #include <nlist.h> 41 #include <link.h> 42 #include <string.h> 43 #include <stdlib.h> 44 #include <unistd.h> 45 46 #include "syscall.h" 47 #include "archdep.h" 48 #include "path.h" 49 #include "util.h" 50 #include "sod.h" 51 52 int _dl_hinthash(char *cp, int vmajor, int vminor); 53 void _dl_maphints(void); 54 55 /* 56 * Populate sod struct for dlopen's call to map_object 57 */ 58 void 59 _dl_build_sod(const char *name, struct sod *sodp) 60 { 61 unsigned int tuplet; 62 int major, minor; 63 char *realname, *tok, *etok, *cp; 64 65 /* default is an absolute or relative path */ 66 sodp->sod_name = (long)_dl_strdup(name); /* strtok is destructive */ 67 if (sodp->sod_name == 0) 68 _dl_exit(7); 69 sodp->sod_library = 0; 70 sodp->sod_major = sodp->sod_minor = 0; 71 72 /* does it look like /^lib/ ? */ 73 if (_dl_strncmp((char *)sodp->sod_name, "lib", 3) != 0) 74 goto backout; 75 76 /* is this a filename? */ 77 if (_dl_strchr((char *)sodp->sod_name, '/')) 78 goto backout; 79 80 /* skip over 'lib' */ 81 cp = (char *)sodp->sod_name + 3; 82 83 realname = cp; 84 85 /* dot guardian */ 86 if ((_dl_strchr(cp, '.') == NULL) || (*(cp+_dl_strlen(cp)-1) == '.')) 87 goto backout; 88 89 cp = _dl_strstr(cp, ".so"); 90 if (cp == NULL) 91 goto backout; 92 93 /* default */ 94 major = minor = -1; 95 96 /* loop through name - parse skipping name */ 97 for (tuplet = 0; (tok = _dl_strsep(&cp, ".")) != NULL; tuplet++) { 98 switch (tuplet) { 99 case 0: 100 /* empty tok, we already skipped to "\.so.*" */ 101 break; 102 case 1: 103 /* 'so' extension */ 104 break; 105 case 2: 106 /* major version extension */ 107 major = _dl_strtol(tok, &etok, 10); 108 if (*tok == '\0' || *etok != '\0') 109 goto backout; 110 break; 111 case 3: 112 /* minor version extension */ 113 minor = _dl_strtol(tok, &etok, 10); 114 if (*tok == '\0' || *etok != '\0') 115 goto backout; 116 break; 117 /* if we get here, it must be weird */ 118 default: 119 goto backout; 120 } 121 } 122 if (realname == NULL) 123 goto backout; 124 cp = (char *)sodp->sod_name; 125 sodp->sod_name = (long)_dl_strdup(realname); 126 if (sodp->sod_name == 0) 127 _dl_exit(7); 128 _dl_free(cp); 129 sodp->sod_library = 1; 130 sodp->sod_major = major; 131 sodp->sod_minor = minor; 132 return; 133 134 backout: 135 _dl_free((char *)sodp->sod_name); 136 sodp->sod_name = (long)_dl_strdup(name); 137 if (sodp->sod_name == 0) 138 _dl_exit(7); 139 } 140 141 void 142 _dl_set_sod(const char *path, struct sod *sod) 143 { 144 char *fname = _dl_strrchr(path, '/'); 145 146 if (fname != NULL) 147 _dl_build_sod(++fname, sod); 148 else 149 _dl_build_sod(path, sod); 150 } 151 152 static struct hints_header *hheader = NULL; 153 static struct hints_bucket *hbuckets; 154 static char *hstrtab; 155 char **_dl_hint_search_path = NULL; 156 157 #define HINTS_VALID (hheader != NULL && hheader != (struct hints_header *)-1) 158 159 void 160 _dl_maphints(void) 161 { 162 struct stat sb; 163 caddr_t addr = MAP_FAILED; 164 long hsize = 0; 165 int hfd; 166 167 if ((hfd = _dl_open(_PATH_LD_HINTS, O_RDONLY | O_CLOEXEC)) < 0) 168 goto bad_hints; 169 170 if (_dl_fstat(hfd, &sb) != 0 || !S_ISREG(sb.st_mode) || 171 sb.st_size < sizeof(struct hints_header) || sb.st_size > LONG_MAX) 172 goto bad_hints; 173 174 hsize = (long)sb.st_size; 175 addr = (void *)_dl_mmap(0, hsize, PROT_READ, MAP_PRIVATE, hfd, 0); 176 if (_dl_mmap_error(addr)) 177 goto bad_hints; 178 179 hheader = (struct hints_header *)addr; 180 if (HH_BADMAG(*hheader) || hheader->hh_ehints > hsize) 181 goto bad_hints; 182 183 if (hheader->hh_version != LD_HINTS_VERSION_2) 184 goto bad_hints; 185 186 hbuckets = (struct hints_bucket *)(addr + hheader->hh_hashtab); 187 hstrtab = (char *)(addr + hheader->hh_strtab); 188 if (hheader->hh_version >= LD_HINTS_VERSION_2) 189 _dl_hint_search_path = _dl_split_path(hstrtab + hheader->hh_dirlist); 190 191 /* close the file descriptor, leaving the hints mapped */ 192 _dl_close(hfd); 193 194 return; 195 196 bad_hints: 197 if (!_dl_mmap_error(addr)) 198 _dl_munmap(addr, hsize); 199 if (hfd != -1) 200 _dl_close(hfd); 201 hheader = (struct hints_header *)-1; 202 } 203 204 char * 205 _dl_findhint(char *name, int major, int minor, char *preferred_path) 206 { 207 struct hints_bucket *bp; 208 209 /* 210 * If not mapped, and we have not tried before, try to map the 211 * hints, if previous attempts failed hheader is -1 and we 212 * do not wish to retry it. 213 */ 214 if (hheader == NULL) 215 _dl_maphints(); 216 217 /* if it failed to map, return failure */ 218 if (!(HINTS_VALID)) 219 return NULL; 220 221 if (hheader->hh_nbucket == 0) 222 return NULL; 223 224 bp = hbuckets + (_dl_hinthash(name, major, minor) % hheader->hh_nbucket); 225 226 while (1) { 227 /* Sanity check */ 228 if (bp->hi_namex >= hheader->hh_strtab_sz) { 229 _dl_printf("Bad name index: %#x\n", bp->hi_namex); 230 _dl_exit(7); 231 break; 232 } 233 if (bp->hi_pathx >= hheader->hh_strtab_sz) { 234 _dl_printf("Bad path index: %#x\n", bp->hi_pathx); 235 _dl_exit(7); 236 break; 237 } 238 239 if (_dl_strcmp(name, hstrtab + bp->hi_namex) == 0) { 240 /* It's `name', check version numbers */ 241 if (bp->hi_major == major && 242 (bp->hi_ndewey < 2 || bp->hi_minor >= minor)) { 243 if (preferred_path == NULL) { 244 return hstrtab + bp->hi_pathx; 245 } else { 246 char *path = hstrtab + bp->hi_pathx; 247 char *edir = _dl_strrchr(path, '/'); 248 249 if ((_dl_strncmp(preferred_path, path, 250 (edir - path)) == 0) && 251 (preferred_path[edir - path] == '\0')) 252 return path; 253 } 254 } 255 } 256 257 if (bp->hi_next == -1) 258 break; 259 260 /* Move on to next in bucket */ 261 bp = &hbuckets[bp->hi_next]; 262 } 263 264 /* No hints available for name */ 265 return NULL; 266 } 267 268 int 269 _dl_hinthash(char *cp, int vmajor, int vminor) 270 { 271 int k = 0; 272 273 while (*cp) 274 k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff; 275 276 k = (((k << 1) + (k >> 14)) ^ (vmajor*257)) & 0x3fff; 277 278 return k; 279 } 280