+++ /dev/null
-/*
-* 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;
-}
git.samba.org / sfrench / samba-autobuild / .git / blobdiff