1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371
|
/*
* Copyright 2003-2016 Gentoo Foundation
* Distributed under the terms of the GNU General Public License v2
*
* Copyright 2003-2012 Ned Ludd - <solar@gentoo.org>
* Copyright 2004-2016 Mike Frysinger - <vapier@gentoo.org>
*/
#include "paxinc.h"
/*
* ld.so.cache logic
*/
#if PAX_LDSO_CACHE
static void *ldcache = NULL;
static size_t ldcache_size = 0;
static char *ldso_cache_buf = NULL;
static size_t ldso_cache_buf_size = 0;
#if defined(__GLIBC__) || defined(__UCLIBC__)
/* Defines can be seen in glibc's sysdeps/generic/ldconfig.h */
#define LDSO_CACHE_MAGIC "ld.so-"
#define LDSO_CACHE_MAGIC_LEN (sizeof LDSO_CACHE_MAGIC -1)
#define LDSO_CACHE_VER "1.7.0"
#define LDSO_CACHE_VER_LEN (sizeof LDSO_CACHE_VER -1)
#define FLAG_ANY -1
#define FLAG_TYPE_MASK 0x00ff
#define FLAG_LIBC4 0x0000
#define FLAG_ELF 0x0001
#define FLAG_ELF_LIBC5 0x0002
#define FLAG_ELF_LIBC6 0x0003
#define FLAG_REQUIRED_MASK 0xff00
#define FLAG_SPARC_LIB64 0x0100
#define FLAG_IA64_LIB64 0x0200
#define FLAG_X8664_LIB64 0x0300
#define FLAG_S390_LIB64 0x0400
#define FLAG_POWERPC_LIB64 0x0500
#define FLAG_MIPS64_LIBN32 0x0600
#define FLAG_MIPS64_LIBN64 0x0700
#define FLAG_X8664_LIBX32 0x0800
#define FLAG_ARM_LIBHF 0x0900
#define FLAG_AARCH64_LIB64 0x0a00
#define FLAG_ARM_LIBSF 0x0b00
#define FLAG_MIPS_LIB32_NAN2008 0x0c00
#define FLAG_MIPS64_LIBN32_NAN2008 0x0d00
#define FLAG_MIPS64_LIBN64_NAN2008 0x0e00
typedef struct {
int flags;
unsigned int sooffset;
unsigned int liboffset;
} libentry_t;
static bool is_compatible(elfobj *elf, libentry_t *libent)
{
int flags = libent->flags & FLAG_REQUIRED_MASK;
/* We assume that ((flags & FLAG_TYPE_MASK) == FLAG_ELF_LIBC6)
* since anything older is very very old and no one cares.
*
* Otherwise we really only need to check here for cases where
* an arch has more than one ABI per bitsize (e.g. x86, x32, and
* x86_64). The default case should be fine otherwise.
*/
if (elf->elf_class == ELFCLASS32) {
const Elf32_Ehdr *ehdr = EHDR32(elf->ehdr);
switch (EGET(ehdr->e_machine)) {
case EM_AARCH64:
break;
case EM_ARM:
if ((flags == FLAG_ARM_LIBHF && (ehdr->e_flags & EF_ARM_ABI_FLOAT_HARD)) ||
(flags == FLAG_ARM_LIBSF && (ehdr->e_flags & EF_ARM_ABI_FLOAT_SOFT)) ||
(flags == 0 && !(ehdr->e_flags & (EF_ARM_ABI_FLOAT_HARD | EF_ARM_ABI_FLOAT_SOFT))))
return true;
break;
case EM_IA_64:
break;
case EM_MIPS: {
int ef_flags = (ehdr->e_flags & (EF_MIPS_ABI2 | EF_MIPS_NAN2008));
if ((flags == 0 && ef_flags == 0) ||
(flags == FLAG_MIPS64_LIBN32 && ef_flags == EF_MIPS_ABI2) ||
(flags == FLAG_MIPS_LIB32_NAN2008 && ef_flags == EF_MIPS_NAN2008) ||
(flags == FLAG_MIPS64_LIBN32_NAN2008 && ef_flags == (EF_MIPS_ABI2 | EF_MIPS_NAN2008)))
return true;
break;
}
case EM_X86_64:
if (flags == FLAG_X8664_LIBX32)
return true;
break;
default:
/* A sane enough default. */
if (flags == 0)
return true;
break;
}
} else {
const Elf64_Ehdr *ehdr = EHDR64(elf->ehdr);
switch (EGET(ehdr->e_machine)) {
case EM_AARCH64:
if (flags == FLAG_AARCH64_LIB64)
return true;
break;
case EM_ARM:
break;
case EM_IA_64:
if (flags == FLAG_IA64_LIB64)
return true;
break;
case EM_MIPS: {
int ef_flags = (ehdr->e_flags & EF_MIPS_NAN2008);
if ((flags == FLAG_MIPS64_LIBN64 && ef_flags == 0) ||
(flags == FLAG_MIPS64_LIBN64_NAN2008 && ef_flags == EF_MIPS_NAN2008))
return true;
break;
}
case EM_X86_64:
if (flags == FLAG_X8664_LIB64)
return true;
break;
default:
/* A sane enough default. */
if (flags != 0)
return true;
break;
}
}
return false;
}
char *ldso_cache_lookup_lib(elfobj *elf, const char *fname)
{
unsigned int nlib;
char *ret = NULL;
char *strs;
typedef struct {
char magic[LDSO_CACHE_MAGIC_LEN];
char version[LDSO_CACHE_VER_LEN];
unsigned int nlibs;
} header_t;
header_t *header;
libentry_t *libent;
if (fname == NULL)
return NULL;
if (ldcache == NULL) {
int fd;
const char *cachefile = root_rel_path("/etc/ld.so.cache");
struct stat st;
if (fstatat(root_fd, cachefile, &st, 0))
return NULL;
fd = openat(root_fd, cachefile, O_RDONLY);
if (fd == -1)
return NULL;
/* cache these values so we only map/unmap the cache file once */
ldcache_size = st.st_size;
header = ldcache = mmap(0, ldcache_size, PROT_READ, MAP_SHARED, fd, 0);
close(fd);
if (ldcache == MAP_FAILED) {
ldcache = NULL;
return NULL;
}
if (memcmp(header->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN) ||
memcmp(header->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN))
{
munmap(ldcache, ldcache_size);
ldcache = NULL;
return NULL;
}
ldso_cache_buf_size = 4096;
ldso_cache_buf = xrealloc(ldso_cache_buf, ldso_cache_buf_size);
} else
header = ldcache;
libent = ldcache + sizeof(header_t);
strs = (char *) &libent[header->nlibs];
for (nlib = 0; nlib < header->nlibs; ++nlib) {
const char *lib;
size_t lib_len;
if (!is_compatible(elf, &libent[nlib]))
continue;
if (strcmp(fname, strs + libent[nlib].sooffset) != 0)
continue;
/* Return first hit because that is how the ldso rolls */
lib = strs + libent[nlib].liboffset;
lib_len = strlen(lib) + 1;
if (lib_len > ldso_cache_buf_size) {
ldso_cache_buf = xrealloc(ldso_cache_buf, ldso_cache_buf_size + 4096);
ldso_cache_buf_size += 4096;
}
memcpy(ldso_cache_buf, lib, lib_len);
ret = ldso_cache_buf;
break;
}
return ret;
}
#endif
static void ldso_cache_cleanup(void)
{
free(ldso_cache_buf);
if (ldcache != NULL)
munmap(ldcache, ldcache_size);
}
#else
# define ldso_cache_cleanup()
#endif /* PAX_LDSO_CACHE */
/*
* ld.so.conf logic
*/
static array_t _ldpaths = array_init_decl;
array_t *ldpaths = &_ldpaths;
#if PAX_LDSO_CONFIG
#if defined(__GLIBC__) || defined(__UCLIBC__) || defined(__NetBSD__)
int ldso_config_load(const char *fname)
{
FILE *fp = NULL;
char *p, *path;
size_t len;
int curr_fd = -1;
fp = fopenat_r(root_fd, root_rel_path(fname));
if (fp == NULL)
return -1;
path = NULL;
len = 0;
while (getline(&path, &len, fp) != -1) {
if ((p = strrchr(path, '\r')) != NULL)
*p = 0;
if ((p = strchr(path, '\n')) != NULL)
*p = 0;
/* recursive includes of the same file will make this segfault. */
if ((memcmp(path, "include", 7) == 0) && isblank(path[7])) {
glob_t gl;
size_t x;
const char *gpath;
/* re-use existing path buffer ... need to be creative */
if (path[8] != '/')
gpath = memcpy(path + 3, "/etc/", 5);
else
gpath = path + 8;
if (root_fd != AT_FDCWD) {
if (curr_fd == -1) {
curr_fd = open(".", O_RDONLY|O_CLOEXEC);
if (fchdir(root_fd))
errp("unable to change to root dir");
}
gpath = root_rel_path(gpath);
}
if (glob(gpath, 0, NULL, &gl) == 0) {
for (x = 0; x < gl.gl_pathc; ++x) {
/* try to avoid direct loops */
if (strcmp(gl.gl_pathv[x], fname) == 0)
continue;
ldso_config_load(gl.gl_pathv[x]);
}
globfree(&gl);
}
/* failed globs are ignored by glibc */
continue;
}
if (*path != '/')
continue;
xarraypush_str(ldpaths, path);
}
free(path);
fclose(fp);
if (curr_fd != -1) {
if (fchdir(curr_fd))
{/* don't care */}
close(curr_fd);
}
return 0;
}
#elif defined(__FreeBSD__) || defined(__DragonFly__)
int ldso_config_load(const char *fname)
{
FILE *fp = NULL;
char *b = NULL, *p;
struct elfhints_hdr hdr;
fp = fopenat_r(root_fd, root_rel_path(fname));
if (fp == NULL)
return -1;
if (fread(&hdr, 1, sizeof(hdr), fp) != sizeof(hdr) ||
hdr.magic != ELFHINTS_MAGIC || hdr.version != 1 ||
fseek(fp, hdr.strtab + hdr.dirlist, SEEK_SET) == -1)
{
fclose(fp);
return -1;
}
b = xmalloc(hdr.dirlistlen + 1);
if (fread(b, 1, hdr.dirlistlen+1, fp) != hdr.dirlistlen+1) {
fclose(fp);
free(b);
return -1;
}
while ((p = strsep(&b, ":"))) {
if (*p == '\0')
continue;
xarraypush_str(ldpaths, p);
}
free(b);
fclose(fp);
return 0;
}
#endif
static void ldso_config_cleanup(void)
{
xarrayfree(ldpaths);
}
#else
# define ldso_config_cleanup()
#endif /* PAX_LDSO_CONFIG */
#ifndef paxldso_cleanup
void paxldso_cleanup(void)
{
ldso_cache_cleanup();
ldso_config_cleanup();
}
#endif
|