int read_cache(void)
{
int fd, i;
struct stat st;
unsigned long size, offset;
void *map;
struct cache_header *hdr;
errno = EBUSY;
if (active_cache)
return error("more than one cachefile");
errno = ENOENT;
sha1_file_directory = getenv(DB_ENVIRONMENT);
if (!sha1_file_directory)
sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
if (access(sha1_file_directory, X_OK) < 0)
return error("no access to SHA1 file directory");
fd = open(get_index_file(), O_RDONLY);
if (fd < 0)
return (errno == ENOENT) ? 0 : error("open failed");
size = 0; // avoid gcc warning
map = (void *)-1;
if (!fstat(fd, &st)) {
size = st.st_size;
errno = EINVAL;
if (size >= sizeof(struct cache_header) + 20)
map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
}
close(fd);
if (-1 == (int)(long)map)
return error("mmap failed");
hdr = map;
if (verify_hdr(hdr, size) < 0)
goto unmap;
active_nr = ntohl(hdr->hdr_entries);
active_alloc = alloc_nr(active_nr);
active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
offset = sizeof(*hdr);
for (i = 0; i < active_nr; i++) {
struct cache_entry *ce = map + offset;
offset = offset + ce_size(ce);
active_cache[i] = ce;
}
return active_nr;
unmap:
munmap(map, size);
errno = EINVAL;
return error("verify header failed");
}
int
process_hdr(const char *dev, int flags, unsigned char *pass, int passlen,
struct tchdr_enc *ehdr, struct tcplay_info **pinfo)
{
struct tchdr_dec *dhdr;
struct tcplay_info *info;
struct tc_cipher_chain *cipher_chain = NULL;
unsigned char *key;
int i, j, found, error;
*pinfo = NULL;
if ((key = alloc_safe_mem(MAX_KEYSZ)) == NULL) {
tc_log(1, "could not allocate safe key memory\n");
return ENOMEM;
}
/* Start search for correct algorithm combination */
found = 0;
for (i = 0; !found && pbkdf_prf_algos[i].name != NULL; i++) {
#ifdef DEBUG
printf("\nTrying PRF algo %s (%d)\n", pbkdf_prf_algos[i].name,
pbkdf_prf_algos[i].iteration_count);
printf("Salt: ");
print_hex(ehdr->salt, 0, sizeof(ehdr->salt));
#endif
error = pbkdf2(&pbkdf_prf_algos[i], (char *)pass, passlen,
ehdr->salt, sizeof(ehdr->salt),
MAX_KEYSZ, key);
if (error) {
tc_log(1, "pbkdf failed for algorithm %s\n",
pbkdf_prf_algos[i].name);
free_safe_mem(key);
return EINVAL;
}
#if 0
printf("Derived Key: ");
print_hex(key, 0, MAX_KEYSZ);
#endif
for (j = 0; !found && tc_cipher_chains[j] != NULL; j++) {
cipher_chain = tc_dup_cipher_chain(tc_cipher_chains[j]);
#ifdef DEBUG
printf("\nTrying cipher chain %d\n", j);
#endif
dhdr = decrypt_hdr(ehdr, cipher_chain, key);
if (dhdr == NULL) {
tc_log(1, "hdr decryption failed for cipher "
"chain %d\n", j);
free_safe_mem(key);
return EINVAL;
}
if (verify_hdr(dhdr)) {
#ifdef DEBUG
printf("tc_str: %.4s, tc_ver: %d, tc_min_ver: %d, "
"crc_keys: %d, sz_vol: %"PRIu64", "
"off_mk_scope: %"PRIu64", sz_mk_scope: %"PRIu64", "
"flags: %d, sec_sz: %d crc_dhdr: %d\n",
dhdr->tc_str, dhdr->tc_ver, dhdr->tc_min_ver,
dhdr->crc_keys, dhdr->sz_vol, dhdr->off_mk_scope,
dhdr->sz_mk_scope, dhdr->flags, dhdr->sec_sz,
dhdr->crc_dhdr);
#endif
found = 1;
} else {
free_safe_mem(dhdr);
tc_free_cipher_chain(cipher_chain);
}
}
}
free_safe_mem(key);
if (!found)
return EINVAL;
if ((info = new_info(dev, flags, cipher_chain,
&pbkdf_prf_algos[i-1], dhdr, 0)) == NULL) {
free_safe_mem(dhdr);
return ENOMEM;
}
*pinfo = info;
return 0;
}