/* * CIFS user-space helper. * Copyright (C) Igor Mammedov (niallain@gmail.com) 2007 * Copyright (C) Jeff Layton (jlayton@samba.org) 2010 * * Used by /sbin/request-key for handling * cifs upcall for kerberos authorization of access to share and * cifs upcall for DFS srver name resolving (IPv4/IPv6 aware). * You should have keyutils installed and add something like the * following lines to /etc/request-key.conf file: create cifs.spnego * * /usr/local/sbin/cifs.upcall %k create dns_resolver * * /usr/local/sbin/cifs.upcall %k * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifdef HAVE_CONFIG_H #include "config.h" #endif /* HAVE_CONFIG_H */ #include #include #ifdef HAVE_KRB5_KRB5_H #include #elif defined(HAVE_KRB5_H) #include #endif #include #include #include #include #include #include #include #include #include #include #include "replace.h" #include "data_blob.h" #include "spnego.h" #include "cifs_spnego.h" #define CIFS_DEFAULT_KRB5_DIR "/tmp" #define CIFS_DEFAULT_KRB5_USER_DIR "/run/user/%U" #define CIFS_DEFAULT_KRB5_PREFIX "krb5cc" #define CIFS_DEFAULT_KRB5_KEYTAB "/etc/krb5.keytab" #define MAX_CCNAME_LEN PATH_MAX + 5 static const char *prog = "cifs.upcall"; typedef enum _sectype { NONE = 0, KRB5, MS_KRB5 } sectype_t; /* * smb_krb5_principal_get_realm * * @brief Get realm of a principal * * @param[in] context The krb5_context * @param[in] principal The principal * @return pointer to the realm * */ static char *cifs_krb5_principal_get_realm(krb5_context context __attribute__ ((unused)), krb5_principal principal) { #ifdef HAVE_KRB5_PRINCIPAL_GET_REALM /* Heimdal */ return krb5_principal_get_realm(context, principal); #elif defined(krb5_princ_realm) /* MIT */ krb5_data *realm; realm = krb5_princ_realm(context, principal); return (char *)realm->data; #else return NULL; #endif } #if !defined(HAVE_KRB5_FREE_UNPARSED_NAME) static void krb5_free_unparsed_name(krb5_context context, char *val) { SAFE_FREE(val); } #endif #if !defined(HAVE_KRB5_AUTH_CON_GETSENDSUBKEY) /* Heimdal */ static krb5_error_code krb5_auth_con_getsendsubkey(krb5_context context, krb5_auth_context auth_context, krb5_keyblock **keyblock) { return krb5_auth_con_getlocalsubkey(context, auth_context, keyblock); } #endif /* does the ccache have a valid TGT? */ static time_t get_tgt_time(const char *ccname) { krb5_context context; krb5_ccache ccache; krb5_cc_cursor cur; krb5_creds creds; krb5_principal principal; time_t credtime = 0; char *realm = NULL; if (krb5_init_context(&context)) { syslog(LOG_DEBUG, "%s: unable to init krb5 context", __func__); return 0; } if (krb5_cc_resolve(context, ccname, &ccache)) { syslog(LOG_DEBUG, "%s: unable to resolve krb5 cache", __func__); goto err_cache; } if (krb5_cc_set_flags(context, ccache, 0)) { syslog(LOG_DEBUG, "%s: unable to set flags", __func__); goto err_cache; } if (krb5_cc_get_principal(context, ccache, &principal)) { syslog(LOG_DEBUG, "%s: unable to get principal", __func__); goto err_princ; } if (krb5_cc_start_seq_get(context, ccache, &cur)) { syslog(LOG_DEBUG, "%s: unable to seq start", __func__); goto err_ccstart; } if ((realm = cifs_krb5_principal_get_realm(context, principal)) == NULL) { syslog(LOG_DEBUG, "%s: unable to get realm", __func__); goto err_ccstart; } while (!credtime && !krb5_cc_next_cred(context, ccache, &cur, &creds)) { char *name; if (krb5_unparse_name(context, creds.server, &name)) { syslog(LOG_DEBUG, "%s: unable to unparse name", __func__); goto err_endseq; } if (krb5_realm_compare(context, creds.server, principal) && !strncasecmp(name, KRB5_TGS_NAME, KRB5_TGS_NAME_SIZE) && !strncasecmp(name + KRB5_TGS_NAME_SIZE + 1, realm, strlen(realm)) && creds.times.endtime > time(NULL)) credtime = creds.times.endtime; krb5_free_cred_contents(context, &creds); krb5_free_unparsed_name(context, name); } err_endseq: krb5_cc_end_seq_get(context, ccache, &cur); err_ccstart: krb5_free_principal(context, principal); err_princ: #if defined(KRB5_TC_OPENCLOSE) krb5_cc_set_flags(context, ccache, KRB5_TC_OPENCLOSE); #endif krb5_cc_close(context, ccache); err_cache: krb5_free_context(context); return credtime; } static int krb5cc_filter(const struct dirent *dirent) { /* subtract 1 for the null terminator */ return !strncmp(dirent->d_name, CIFS_DEFAULT_KRB5_PREFIX, sizeof(CIFS_DEFAULT_KRB5_PREFIX) - 1); } static char * init_cc_from_keytab(const char *keytab_name, const char *user) { krb5_context context = NULL; krb5_error_code ret; krb5_creds my_creds; krb5_keytab keytab = NULL; krb5_principal me = NULL; krb5_ccache cc = NULL; char *ccname = NULL; memset((char *) &my_creds, 0, sizeof(my_creds)); ret = krb5_init_context(&context); if (ret) { syslog(LOG_DEBUG, "krb5_init_context: %d", (int)ret); goto icfk_cleanup; } ret = krb5_kt_resolve(context, keytab_name, &keytab); if (ret) { syslog(LOG_DEBUG, "krb5_kt_resolve: %d", (int)ret); goto icfk_cleanup; } ret = krb5_parse_name(context, user, &me); if (ret) { syslog(LOG_DEBUG, "krb5_parse_name: %d", (int)ret); goto icfk_cleanup; } ret = krb5_get_init_creds_keytab(context, &my_creds, me, keytab, 0, NULL, NULL); if (ret) { syslog(LOG_DEBUG, "krb5_get_init_creds_keytab: %d", (int)ret); goto icfk_cleanup; } ret = krb5_cc_default(context, &cc); if (ret) { syslog(LOG_DEBUG, "krb5_cc_default: %d", (int)ret); goto icfk_cleanup; } ret = krb5_cc_initialize(context, cc, me); if (ret) { syslog(LOG_DEBUG, "krb5_cc_initialize: %d", (int)ret); goto icfk_cleanup; } ret = krb5_cc_store_cred(context, cc, &my_creds); if (ret) syslog(LOG_DEBUG, "krb5_cc_store_cred: %d", (int)ret); ccname = strdup(krb5_cc_default_name(context)); if (ccname == NULL) syslog(LOG_ERR, "Unable to allocate memory"); icfk_cleanup: my_creds.client = 0; krb5_free_cred_contents(context, &my_creds); if (me) krb5_free_principal(context, me); if (cc) krb5_cc_close(context, cc); if (keytab) krb5_kt_close(context, keytab); if (context) krb5_free_context(context); return ccname; } /* resolve a pattern to an actual directory path */ static char *resolve_krb5_dir(const char *pattern, uid_t uid) { char name[MAX_CCNAME_LEN]; int i; size_t j; for (i = 0, j = 0; (pattern[i] != '\0') && (j < sizeof(name)); i++) { switch (pattern[i]) { case '%': switch (pattern[i + 1]) { case '%': name[j++] = pattern[i]; i++; break; case 'U': j += snprintf(name + j, sizeof(name) - j, "%lu", (unsigned long) uid); i++; break; } break; default: name[j++] = pattern[i]; break; } } if ((j > 0) && (j < sizeof(name))) return strndup(name, MAX_CCNAME_LEN); else return NULL; } /* search for a credcache that looks like a likely candidate */ static char *find_krb5_cc(const char *dirname, uid_t uid, char **best_cache, time_t *best_time) { struct dirent **namelist; struct stat sbuf; char ccname[MAX_CCNAME_LEN], *credpath; int i, n; time_t cred_time; n = scandir(dirname, &namelist, krb5cc_filter, NULL); if (n < 0) { syslog(LOG_DEBUG, "%s: scandir error on directory '%s': %s", __func__, dirname, strerror(errno)); return NULL; } for (i = 0; i < n; i++) { snprintf(ccname, sizeof(ccname), "FILE:%s/%s", dirname, namelist[i]->d_name); credpath = ccname + 5; syslog(LOG_DEBUG, "%s: considering %s", __func__, credpath); if (lstat(credpath, &sbuf)) { syslog(LOG_DEBUG, "%s: stat error on '%s': %s", __func__, credpath, strerror(errno)); free(namelist[i]); continue; } if (sbuf.st_uid != uid) { syslog(LOG_DEBUG, "%s: %s is owned by %u, not %u", __func__, credpath, sbuf.st_uid, uid); free(namelist[i]); continue; } if (S_ISDIR(sbuf.st_mode)) { snprintf(ccname, sizeof(ccname), "DIR:%s/%s", dirname, namelist[i]->d_name); credpath = ccname + 4; } else if (!S_ISREG(sbuf.st_mode)) { syslog(LOG_DEBUG, "%s: %s is not a regular file", __func__, credpath); free(namelist[i]); continue; } if (!(cred_time = get_tgt_time(ccname))) { syslog(LOG_DEBUG, "%s: %s is not a valid credcache.", __func__, ccname); free(namelist[i]); continue; } if (cred_time <= *best_time) { syslog(LOG_DEBUG, "%s: %s expires sooner than current " "best.", __func__, ccname); free(namelist[i]); continue; } syslog(LOG_DEBUG, "%s: %s is valid ccache", __func__, ccname); free(*best_cache); *best_cache = strndup(ccname, MAX_CCNAME_LEN); *best_time = cred_time; free(namelist[i]); } free(namelist); return *best_cache; } static int cifs_krb5_get_req(const char *host, const char *ccname, DATA_BLOB * mechtoken, DATA_BLOB * sess_key) { krb5_error_code ret; krb5_keyblock *tokb; krb5_context context; krb5_ccache ccache; krb5_creds in_creds, *out_creds; krb5_data apreq_pkt, in_data; krb5_auth_context auth_context = NULL; #if defined(HAVE_KRB5_AUTH_CON_SETADDRS) && defined(HAVE_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE) static const uint8_t gss_cksum[24] = { 0x10, 0x00, /* ... */}; #endif ret = krb5_init_context(&context); if (ret) { syslog(LOG_DEBUG, "%s: unable to init krb5 context", __func__); return ret; } ret = krb5_cc_resolve(context, ccname, &ccache); if (ret) { syslog(LOG_DEBUG, "%s: unable to resolve %s to ccache\n", __func__, ccname); goto out_free_context; } memset(&in_creds, 0, sizeof(in_creds)); ret = krb5_cc_get_principal(context, ccache, &in_creds.client); if (ret) { syslog(LOG_DEBUG, "%s: unable to get client principal name", __func__); goto out_free_ccache; } ret = krb5_sname_to_principal(context, host, "cifs", KRB5_NT_UNKNOWN, &in_creds.server); if (ret) { syslog(LOG_DEBUG, "%s: unable to convert sname to princ (%s).", __func__, host); goto out_free_principal; } ret = krb5_get_credentials(context, 0, ccache, &in_creds, &out_creds); krb5_free_principal(context, in_creds.server); if (ret) { syslog(LOG_DEBUG, "%s: unable to get credentials for %s", __func__, host); goto out_free_principal; } in_data.length = 0; in_data.data = NULL; ret = krb5_auth_con_init(context, &auth_context); if (ret) { syslog(LOG_DEBUG, "%s: unable to create auth_context: %d", __func__, ret); goto out_free_creds; } #if defined(HAVE_KRB5_AUTH_CON_SETADDRS) && defined(HAVE_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE) /* Ensure we will get an addressless ticket. */ ret = krb5_auth_con_setaddrs(context, auth_context, NULL, NULL); if (ret) { syslog(LOG_DEBUG, "%s: unable to set NULL addrs: %d", __func__, ret); goto out_free_auth; } /* * Create a GSSAPI checksum (0x8003), see RFC 4121. * * The current layout is * * 0x10, 0x00, 0x00, 0x00 - length = 16 * 0x00, 0x00, 0x00, 0x00 - channel binding info - 16 zero bytes * 0x00, 0x00, 0x00, 0x00 * 0x00, 0x00, 0x00, 0x00 * 0x00, 0x00, 0x00, 0x00 * 0x00, 0x00, 0x00, 0x00 - flags * * GSS_C_NO_CHANNEL_BINDINGS means 16 zero bytes, * this is needed to work against some closed source * SMB servers. * * See https://bugzilla.samba.org/show_bug.cgi?id=7890 */ in_data.data = discard_const_p(char, gss_cksum); in_data.length = 24; /* MIT krb5 < 1.7 is missing the prototype, but still has the symbol */ #if !HAVE_DECL_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE krb5_error_code krb5_auth_con_set_req_cksumtype( krb5_context context, krb5_auth_context auth_context, krb5_cksumtype cksumtype); #endif ret = krb5_auth_con_set_req_cksumtype(context, auth_context, 0x8003); if (ret) { syslog(LOG_DEBUG, "%s: unable to set 0x8003 checksum", __func__); goto out_free_auth; } #endif apreq_pkt.length = 0; apreq_pkt.data = NULL; ret = krb5_mk_req_extended(context, &auth_context, AP_OPTS_USE_SUBKEY, &in_data, out_creds, &apreq_pkt); if (ret) { syslog(LOG_DEBUG, "%s: unable to make AP-REQ for %s", __func__, host); goto out_free_auth; } ret = krb5_auth_con_getsendsubkey(context, auth_context, &tokb); if (ret) { syslog(LOG_DEBUG, "%s: unable to get session key for %s", __func__, host); goto out_free_auth; } *mechtoken = data_blob(apreq_pkt.data, apreq_pkt.length); *sess_key = data_blob(KRB5_KEY_DATA(tokb), KRB5_KEY_LENGTH(tokb)); krb5_free_keyblock(context, tokb); out_free_auth: krb5_auth_con_free(context, auth_context); out_free_creds: krb5_free_creds(context, out_creds); out_free_principal: krb5_free_principal(context, in_creds.client); out_free_ccache: #if defined(KRB5_TC_OPENCLOSE) krb5_cc_set_flags(context, ccache, KRB5_TC_OPENCLOSE); #endif krb5_cc_close(context, ccache); out_free_context: krb5_free_context(context); return ret; } /* * Prepares AP-REQ data for mechToken and gets session key * Uses credentials from cache. It will not ask for password * you should receive credentials for yuor name manually using * kinit or whatever you wish. * * in: * oid - string with OID/ Could be OID_KERBEROS5 * or OID_KERBEROS5_OLD * principal - Service name. * Could be "cifs/FQDN" for KRB5 OID * or for MS_KRB5 OID style server principal * like "pdc$@YOUR.REALM.NAME" * * out: * secblob - pointer for spnego wrapped AP-REQ data to be stored * sess_key- pointer for SessionKey data to be stored * * ret: 0 - success, others - failure */ static int handle_krb5_mech(const char *oid, const char *host, DATA_BLOB * secblob, DATA_BLOB * sess_key, const char *ccname) { int retval; DATA_BLOB tkt, tkt_wrapped; syslog(LOG_DEBUG, "%s: getting service ticket for %s", __func__, host); /* get a kerberos ticket for the service and extract the session key */ retval = cifs_krb5_get_req(host, ccname, &tkt, sess_key); if (retval) { syslog(LOG_DEBUG, "%s: failed to obtain service ticket (%d)", __func__, retval); return retval; } syslog(LOG_DEBUG, "%s: obtained service ticket", __func__); /* wrap that up in a nice GSS-API wrapping */ tkt_wrapped = spnego_gen_krb5_wrap(tkt, TOK_ID_KRB_AP_REQ); /* and wrap that in a shiny SPNEGO wrapper */ *secblob = gen_negTokenInit(oid, tkt_wrapped); data_blob_free(&tkt_wrapped); data_blob_free(&tkt); return retval; } #define DKD_HAVE_HOSTNAME 0x1 #define DKD_HAVE_VERSION 0x2 #define DKD_HAVE_SEC 0x4 #define DKD_HAVE_IP 0x8 #define DKD_HAVE_UID 0x10 #define DKD_HAVE_PID 0x20 #define DKD_HAVE_CREDUID 0x40 #define DKD_HAVE_USERNAME 0x80 #define DKD_MUSTHAVE_SET (DKD_HAVE_HOSTNAME|DKD_HAVE_VERSION|DKD_HAVE_SEC) struct decoded_args { int ver; char *hostname; char *ip; char *username; uid_t uid; uid_t creduid; pid_t pid; sectype_t sec; }; static unsigned int decode_key_description(const char *desc, struct decoded_args *arg) { int len; int retval = 0; char *pos; const char *tkn = desc; do { pos = index(tkn, ';'); if (strncmp(tkn, "host=", 5) == 0) { if (pos == NULL) len = strlen(tkn); else len = pos - tkn; len -= 5; SAFE_FREE(arg->hostname); arg->hostname = strndup(tkn + 5, len); if (arg->hostname == NULL) { syslog(LOG_ERR, "Unable to allocate memory"); return 1; } retval |= DKD_HAVE_HOSTNAME; syslog(LOG_DEBUG, "host=%s", arg->hostname); } else if (!strncmp(tkn, "ip4=", 4) || !strncmp(tkn, "ip6=", 4)) { if (pos == NULL) len = strlen(tkn); else len = pos - tkn; len -= 4; SAFE_FREE(arg->ip); arg->ip = strndup(tkn + 4, len); if (arg->ip == NULL) { syslog(LOG_ERR, "Unable to allocate memory"); return 1; } retval |= DKD_HAVE_IP; syslog(LOG_DEBUG, "ip=%s", arg->ip); } else if (strncmp(tkn, "user=", 5) == 0) { if (pos == NULL) len = strlen(tkn); else len = pos - tkn; len -= 5; SAFE_FREE(arg->username); arg->username = strndup(tkn + 5, len); if (arg->username == NULL) { syslog(LOG_ERR, "Unable to allocate memory"); return 1; } retval |= DKD_HAVE_USERNAME; syslog(LOG_DEBUG, "user=%s", arg->username); } else if (strncmp(tkn, "pid=", 4) == 0) { errno = 0; arg->pid = strtol(tkn + 4, NULL, 0); if (errno != 0) { syslog(LOG_ERR, "Invalid pid format: %s", strerror(errno)); return 1; } syslog(LOG_DEBUG, "pid=%u", arg->pid); retval |= DKD_HAVE_PID; } else if (strncmp(tkn, "sec=", 4) == 0) { if (strncmp(tkn + 4, "krb5", 4) == 0) { retval |= DKD_HAVE_SEC; arg->sec = KRB5; } else if (strncmp(tkn + 4, "mskrb5", 6) == 0) { retval |= DKD_HAVE_SEC; arg->sec = MS_KRB5; } syslog(LOG_DEBUG, "sec=%d", arg->sec); } else if (strncmp(tkn, "uid=", 4) == 0) { errno = 0; arg->uid = strtol(tkn + 4, NULL, 16); if (errno != 0) { syslog(LOG_ERR, "Invalid uid format: %s", strerror(errno)); return 1; } retval |= DKD_HAVE_UID; syslog(LOG_DEBUG, "uid=%u", arg->uid); } else if (strncmp(tkn, "creduid=", 8) == 0) { errno = 0; arg->creduid = strtol(tkn + 8, NULL, 16); if (errno != 0) { syslog(LOG_ERR, "Invalid creduid format: %s", strerror(errno)); return 1; } retval |= DKD_HAVE_CREDUID; syslog(LOG_DEBUG, "creduid=%u", arg->creduid); } else if (strncmp(tkn, "ver=", 4) == 0) { /* if version */ errno = 0; arg->ver = strtol(tkn + 4, NULL, 16); if (errno != 0) { syslog(LOG_ERR, "Invalid version format: %s", strerror(errno)); return 1; } retval |= DKD_HAVE_VERSION; syslog(LOG_DEBUG, "ver=%d", arg->ver); } if (pos == NULL) break; tkn = pos + 1; } while (tkn); return retval; } static int cifs_resolver(const key_serial_t key, const char *key_descr) { int c; struct addrinfo *addr; char ip[INET6_ADDRSTRLEN]; void *p; const char *keyend = key_descr; /* skip next 4 ';' delimiters to get to description */ for (c = 1; c <= 4; c++) { keyend = index(keyend + 1, ';'); if (!keyend) { syslog(LOG_ERR, "invalid key description: %s", key_descr); return 1; } } keyend++; /* resolve name to ip */ c = getaddrinfo(keyend, NULL, NULL, &addr); if (c) { syslog(LOG_ERR, "unable to resolve hostname: %s [%s]", keyend, gai_strerror(c)); return 1; } /* conver ip to string form */ if (addr->ai_family == AF_INET) p = &(((struct sockaddr_in *)addr->ai_addr)->sin_addr); else p = &(((struct sockaddr_in6 *)addr->ai_addr)->sin6_addr); if (!inet_ntop(addr->ai_family, p, ip, sizeof(ip))) { syslog(LOG_ERR, "%s: inet_ntop: %s", __func__, strerror(errno)); freeaddrinfo(addr); return 1; } /* setup key */ c = keyctl_instantiate(key, ip, strlen(ip) + 1, 0); if (c == -1) { syslog(LOG_ERR, "%s: keyctl_instantiate: %s", __func__, strerror(errno)); freeaddrinfo(addr); return 1; } freeaddrinfo(addr); return 0; } /* * Older kernels sent IPv6 addresses without colons. Well, at least * they're fixed-length strings. Convert these addresses to have colon * delimiters to make getaddrinfo happy. */ static void convert_inet6_addr(const char *from, char *to) { int i = 1; while (*from) { *to++ = *from++; if (!(i++ % 4) && *from) *to++ = ':'; } *to = 0; } static int ip_to_fqdn(const char *addrstr, char *host, size_t hostlen) { int rc; struct addrinfo hints = {.ai_flags = AI_NUMERICHOST }; struct addrinfo *res; const char *ipaddr = addrstr; char converted[INET6_ADDRSTRLEN + 1]; if ((strlen(ipaddr) > INET_ADDRSTRLEN) && !strchr(ipaddr, ':')) { convert_inet6_addr(ipaddr, converted); ipaddr = converted; } rc = getaddrinfo(ipaddr, NULL, &hints, &res); if (rc) { syslog(LOG_DEBUG, "%s: failed to resolve %s to " "ipaddr: %s", __func__, ipaddr, rc == EAI_SYSTEM ? strerror(errno) : gai_strerror(rc)); return rc; } rc = getnameinfo(res->ai_addr, res->ai_addrlen, host, hostlen, NULL, 0, NI_NAMEREQD); freeaddrinfo(res); if (rc) { syslog(LOG_DEBUG, "%s: failed to resolve %s to fqdn: %s", __func__, ipaddr, rc == EAI_SYSTEM ? strerror(errno) : gai_strerror(rc)); return rc; } syslog(LOG_DEBUG, "%s: resolved %s to %s", __func__, ipaddr, host); return 0; } /* walk a string and lowercase it in-place */ static void lowercase_string(char *c) { while(*c) { *c = tolower(*c); ++c; } } static void usage(void) { fprintf(stderr, "Usage: %s [-k /path/to/krb5.conf] [-t] [-v] [-l] key_serial\n", prog); } const struct option long_options[] = { {"krb5conf", 1, NULL, 'k'}, {"legacy-uid", 0, NULL, 'l'}, {"trust-dns", 0, NULL, 't'}, {"version", 0, NULL, 'v'}, {NULL, 0, NULL, 0} }; int main(const int argc, char *const argv[]) { struct cifs_spnego_msg *keydata = NULL; DATA_BLOB secblob = data_blob_null; DATA_BLOB sess_key = data_blob_null; key_serial_t key = 0; size_t datalen; unsigned int have; long rc = 1; int c, try_dns = 0, legacy_uid = 0; char *buf, *ccdir = NULL, *ccname = NULL, *best_cache = NULL; char hostbuf[NI_MAXHOST], *host; struct decoded_args arg; const char *oid; uid_t uid; char *keytab_name = CIFS_DEFAULT_KRB5_KEYTAB; time_t best_time = 0; hostbuf[0] = '\0'; memset(&arg, 0, sizeof(arg)); openlog(prog, 0, LOG_DAEMON); while ((c = getopt_long(argc, argv, "ck:ltv", long_options, NULL)) != -1) { switch (c) { case 'c': /* legacy option -- skip it */ break; case 't': try_dns++; break; case 'k': if (setenv("KRB5_CONFIG", optarg, 1) != 0) { syslog(LOG_ERR, "unable to set $KRB5_CONFIG: %d", errno); goto out; } break; case 'l': legacy_uid++; break; case 'v': printf("version: %s\n", VERSION); goto out; default: syslog(LOG_ERR, "unknown option: %c", c); goto out; } } /* is there a key? */ if (argc <= optind) { usage(); goto out; } /* get key and keyring values */ errno = 0; key = strtol(argv[optind], NULL, 10); if (errno != 0) { key = 0; syslog(LOG_ERR, "Invalid key format: %s", strerror(errno)); goto out; } rc = keyctl_describe_alloc(key, &buf); if (rc == -1) { syslog(LOG_ERR, "keyctl_describe_alloc failed: %s", strerror(errno)); rc = 1; goto out; } syslog(LOG_DEBUG, "key description: %s", buf); if ((strncmp(buf, "cifs.resolver", sizeof("cifs.resolver") - 1) == 0) || (strncmp(buf, "dns_resolver", sizeof("dns_resolver") - 1) == 0)) { rc = cifs_resolver(key, buf); goto out; } have = decode_key_description(buf, &arg); SAFE_FREE(buf); if ((have & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) { syslog(LOG_ERR, "unable to get necessary params from key " "description (0x%x)", have); rc = 1; goto out; } if (arg.ver > CIFS_SPNEGO_UPCALL_VERSION) { syslog(LOG_ERR, "incompatible kernel upcall version: 0x%x", arg.ver); rc = 1; goto out; } if (strlen(arg.hostname) >= NI_MAXHOST) { syslog(LOG_ERR, "hostname provided by kernel is too long"); rc = 1; goto out; } if (!legacy_uid && (have & DKD_HAVE_CREDUID)) uid = arg.creduid; else if (have & DKD_HAVE_UID) uid = arg.uid; else { /* no uid= or creduid= parm -- something is wrong */ syslog(LOG_ERR, "No uid= or creduid= parm specified"); rc = 1; goto out; } rc = setuid(uid); if (rc == -1) { syslog(LOG_ERR, "setuid: %s", strerror(errno)); goto out; } ccdir = resolve_krb5_dir(CIFS_DEFAULT_KRB5_USER_DIR, uid); if (ccdir != NULL) find_krb5_cc(ccdir, uid, &best_cache, &best_time); ccname = find_krb5_cc(CIFS_DEFAULT_KRB5_DIR, uid, &best_cache, &best_time); SAFE_FREE(ccdir); /* Couldn't find credcache? Try to use keytab */ if (ccname == NULL && arg.username != NULL) ccname = init_cc_from_keytab(keytab_name, arg.username); host = arg.hostname; // do mech specific authorization switch (arg.sec) { case MS_KRB5: case KRB5: /* * Andrew Bartlett's suggested scheme for picking a principal * name, based on a supplied hostname. * * INPUT: fooo * TRY in order: * cifs/fooo@REALM * cifs/fooo.@REALM * * INPUT: bar.example.com * TRY only: * cifs/bar.example.com@REALM */ if (arg.sec == MS_KRB5) oid = OID_KERBEROS5_OLD; else oid = OID_KERBEROS5; retry_new_hostname: lowercase_string(host); rc = handle_krb5_mech(oid, host, &secblob, &sess_key, ccname); if (!rc) break; /* * If hostname has a '.', assume it's a FQDN, otherwise we * want to guess the domainname. */ if (!strchr(host, '.')) { struct addrinfo hints; struct addrinfo *ai; char *domainname; char fqdn[NI_MAXHOST]; /* * use getaddrinfo() to resolve the hostname of the * server and set ai_canonname. */ memset(&hints, 0, sizeof(hints)); hints.ai_family = AF_UNSPEC; hints.ai_flags = AI_CANONNAME; rc = getaddrinfo(host, NULL, &hints, &ai); if (rc) { syslog(LOG_ERR, "Unable to resolve host address: %s [%s]", host, gai_strerror(rc)); break; } /* scan forward to first '.' in ai_canonnname */ domainname = strchr(ai->ai_canonname, '.'); if (!domainname) { rc = -EINVAL; freeaddrinfo(ai); break; } lowercase_string(domainname); rc = snprintf(fqdn, sizeof(fqdn), "%s%s", host, domainname); freeaddrinfo(ai); if (rc < 0 || (size_t)rc >= sizeof(fqdn)) { syslog(LOG_ERR, "Problem setting hostname in string: %ld", rc); rc = -EINVAL; break; } rc = handle_krb5_mech(oid, fqdn, &secblob, &sess_key, ccname); if (!rc) break; } if (!try_dns || !(have & DKD_HAVE_IP)) break; rc = ip_to_fqdn(arg.ip, hostbuf, sizeof(hostbuf)); if (rc) break; try_dns = 0; host = hostbuf; goto retry_new_hostname; default: syslog(LOG_ERR, "sectype: %d is not implemented", arg.sec); rc = 1; break; } if (rc) { syslog(LOG_DEBUG, "Unable to obtain service ticket"); goto out; } /* pack SecurityBlob and SessionKey into downcall packet */ datalen = sizeof(struct cifs_spnego_msg) + secblob.length + sess_key.length; keydata = (struct cifs_spnego_msg *)calloc(sizeof(char), datalen); if (!keydata) { rc = 1; goto out; } keydata->version = arg.ver; keydata->flags = 0; keydata->sesskey_len = sess_key.length; keydata->secblob_len = secblob.length; memcpy(&(keydata->data), sess_key.data, sess_key.length); memcpy(&(keydata->data) + keydata->sesskey_len, secblob.data, secblob.length); /* setup key */ rc = keyctl_instantiate(key, keydata, datalen, 0); if (rc == -1) { syslog(LOG_ERR, "keyctl_instantiate: %s", strerror(errno)); goto out; } /* BB: maybe we need use timeout for key: for example no more then * ticket lifietime? */ /* keyctl_set_timeout( key, 60); */ out: /* * on error, negatively instantiate the key ourselves so that we can * make sure the kernel doesn't hang it off of a searchable keyring * and interfere with the next attempt to instantiate the key. */ if (rc != 0 && key == 0) { syslog(LOG_DEBUG, "Negating key"); keyctl_negate(key, 1, KEY_REQKEY_DEFL_DEFAULT); } data_blob_free(&secblob); data_blob_free(&sess_key); SAFE_FREE(ccname); SAFE_FREE(arg.hostname); SAFE_FREE(arg.ip); SAFE_FREE(arg.username); SAFE_FREE(keydata); syslog(LOG_DEBUG, "Exit status %ld", rc); return rc; }