diff options
Diffstat (limited to 'client/cifs.upcall.c')
| -rw-r--r-- | client/cifs.upcall.c | 656 |
1 files changed, 0 insertions, 656 deletions
diff --git a/client/cifs.upcall.c b/client/cifs.upcall.c deleted file mode 100644 index 42632a0da0..0000000000 --- a/client/cifs.upcall.c +++ /dev/null @@ -1,656 +0,0 @@ -/* -* CIFS user-space helper. -* Copyright (C) Igor Mammedov (niallain@gmail.com) 2007 -* Copyright (C) Jeff Layton (jlayton@redhat.com) 2009 -* -* 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 -*/ - -#include "includes.h" -#include "../libcli/auth/spnego.h" -#include "smb_krb5.h" -#include <keyutils.h> -#include <getopt.h> - -#include "cifs_spnego.h" - -#define CIFS_DEFAULT_KRB5_DIR "/tmp" -#define CIFS_DEFAULT_KRB5_PREFIX "krb5cc_" - -#define MAX_CCNAME_LEN PATH_MAX + 5 - -const char *CIFSSPNEGO_VERSION = "1.3"; -static const char *prog = "cifs.upcall"; -typedef enum _sectype { - NONE = 0, - KRB5, - MS_KRB5 -} sectype_t; - -/* 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; - TALLOC_CTX *mem_ctx; - - 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 = smb_krb5_principal_get_realm(context, principal)) == NULL) { - syslog(LOG_DEBUG, "%s: unable to get realm", __func__); - goto err_ccstart; - } - - mem_ctx = talloc_init("cifs.upcall"); - while (!credtime && !krb5_cc_next_cred(context, ccache, &cur, &creds)) { - char *name; - if (smb_krb5_unparse_name(mem_ctx, context, creds.server, &name)) { - syslog(LOG_DEBUG, "%s: unable to unparse name", __func__); - goto err_endseq; - } - if (krb5_realm_compare(context, creds.server, principal) && - strnequal(name, KRB5_TGS_NAME, KRB5_TGS_NAME_SIZE) && - strnequal(name+KRB5_TGS_NAME_SIZE+1, realm, strlen(realm)) && - creds.times.endtime > time(NULL)) - credtime = creds.times.endtime; - krb5_free_cred_contents(context, &creds); - TALLOC_FREE(name); - } -err_endseq: - TALLOC_FREE(mem_ctx); - 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) -{ - if (strstr(dirent->d_name, CIFS_DEFAULT_KRB5_PREFIX)) - return 1; - else - return 0; -} - -/* search for a credcache that looks like a likely candidate */ -static char * -find_krb5_cc(const char *dirname, uid_t uid) -{ - struct dirent **namelist; - struct stat sbuf; - char ccname[MAX_CCNAME_LEN], *credpath, *best_cache = NULL; - int i, n; - time_t cred_time, best_time = 0; - - 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_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 = SMB_STRNDUP(ccname, MAX_CCNAME_LEN); - best_time = cred_time; - free(namelist[i]); - } - free(namelist); - - return best_cache; -} - -/* - * 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 *principal, 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__, - principal); - - /* get a kerberos ticket for the service and extract the session key */ - retval = cli_krb5_get_ticket(principal, 0, &tkt, sess_key, 0, ccname, - NULL, NULL); - - 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_MUSTHAVE_SET (DKD_HAVE_HOSTNAME|DKD_HAVE_VERSION|DKD_HAVE_SEC) - -struct decoded_args { - int ver; - char *hostname; - char *ip; - uid_t uid; - 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 -= 4; - SAFE_FREE(arg->hostname); - arg->hostname = SMB_XMALLOC_ARRAY(char, len); - strlcpy(arg->hostname, tkn + 5, len); - retval |= DKD_HAVE_HOSTNAME; - } else if (!strncmp(tkn, "ip4=", 4) || - !strncmp(tkn, "ip6=", 4)) { - if (pos == NULL) - len = strlen(tkn); - else - len = pos - tkn; - - len -= 3; - SAFE_FREE(arg->ip); - arg->ip = SMB_XMALLOC_ARRAY(char, len); - strlcpy(arg->ip, tkn + 4, len); - retval |= DKD_HAVE_IP; - } 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; - } else { - 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; - } - } 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; - } else { - retval |= DKD_HAVE_UID; - } - } 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; - } else { - retval |= DKD_HAVE_VERSION; - } - } - 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; -} - -static void -usage(void) -{ - syslog(LOG_INFO, "Usage: %s [-t] [-v] key_serial", prog); - fprintf(stderr, "Usage: %s [-t] [-v] key_serial\n", prog); -} - -const struct option long_options[] = { - { "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; - char *buf, *princ = NULL, *ccname = NULL; - char hostbuf[NI_MAXHOST], *host; - struct decoded_args arg = { }; - const char *oid; - - hostbuf[0] = '\0'; - - openlog(prog, 0, LOG_DAEMON); - - while ((c = getopt_long(argc, argv, "ctv", long_options, NULL)) != -1) { - switch (c) { - case 'c': - /* legacy option -- skip it */ - break; - case 't': - try_dns++; - break; - case 'v': - printf("version: %s\n", CIFSSPNEGO_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 (have & DKD_HAVE_UID) { - rc = setuid(arg.uid); - if (rc == -1) { - syslog(LOG_ERR, "setuid: %s", strerror(errno)); - goto out; - } - - ccname = find_krb5_cc(CIFS_DEFAULT_KRB5_DIR, arg.uid); - } - - host = arg.hostname; - - // do mech specific authorization - switch (arg.sec) { - case MS_KRB5: - case KRB5: -retry_new_hostname: - /* for "cifs/" service name + terminating 0 */ - datalen = strlen(host) + 5 + 1; - princ = SMB_XMALLOC_ARRAY(char, datalen); - if (!princ) { - rc = -ENOMEM; - break; - } - - if (arg.sec == MS_KRB5) - oid = OID_KERBEROS5_OLD; - else - oid = OID_KERBEROS5; - - /* - * try getting a cifs/ principal first and then fall back to - * getting a host/ principal if that doesn't work. - */ - strlcpy(princ, "cifs/", datalen); - strlcpy(princ + 5, host, datalen - 5); - rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname); - if (!rc) - break; - - memcpy(princ, "host/", 5); - rc = handle_krb5_mech(oid, princ, &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; - - SAFE_FREE(princ); - try_dns = 0; - host = hostbuf; - goto retry_new_hostname; - default: - syslog(LOG_ERR, "sectype: %d is not implemented", arg.sec); - rc = 1; - break; - } - - SAFE_FREE(princ); - - if (rc) - 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*)SMB_XMALLOC_ARRAY(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) - 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(keydata); - return rc; -} |