diff options
Diffstat (limited to 'source3/client/cifs.upcall.c')
| -rw-r--r-- | source3/client/cifs.upcall.c | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/source3/client/cifs.upcall.c b/source3/client/cifs.upcall.c new file mode 100644 index 0000000000..4110de35fd --- /dev/null +++ b/source3/client/cifs.upcall.c @@ -0,0 +1,391 @@ +/* +* CIFS user-space helper. +* Copyright (C) Igor Mammedov (niallain@gmail.com) 2007 +* +* 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 <keyutils.h> + +#include "cifs_spnego.h" + +const char *CIFSSPNEGO_VERSION = "1.2"; +static const char *prog = "cifs.upcall"; +typedef enum _secType { + NONE = 0, + KRB5, + MS_KRB5 +} secType_t; + +/* + * 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) +{ + int retval; + DATA_BLOB tkt, tkt_wrapped; + + /* get a kerberos ticket for the service and extract the session key */ + retval = cli_krb5_get_ticket(principal, 0, + &tkt, sess_key, 0, NULL, NULL); + + if (retval) + return retval; + + /* 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 1 +#define DKD_HAVE_VERSION 2 +#define DKD_HAVE_SEC 4 +#define DKD_HAVE_IPV4 8 +#define DKD_HAVE_IPV6 16 +#define DKD_HAVE_UID 32 +#define DKD_MUSTHAVE_SET (DKD_HAVE_HOSTNAME|DKD_HAVE_VERSION|DKD_HAVE_SEC) + +static int +decode_key_description(const char *desc, int *ver, secType_t * sec, + char **hostname, uid_t * uid) +{ + int retval = 0; + char *pos; + const char *tkn = desc; + + do { + pos = index(tkn, ';'); + if (strncmp(tkn, "host=", 5) == 0) { + int len; + + if (pos == NULL) { + len = strlen(tkn); + } else { + len = pos - tkn; + } + len -= 4; + SAFE_FREE(*hostname); + *hostname = SMB_XMALLOC_ARRAY(char, len); + strlcpy(*hostname, tkn + 5, len); + retval |= DKD_HAVE_HOSTNAME; + } else if (strncmp(tkn, "ipv4=", 5) == 0) { + /* BB: do we need it if we have hostname already? */ + } else if (strncmp(tkn, "ipv6=", 5) == 0) { + /* BB: do we need it if we have hostname already? */ + } else if (strncmp(tkn, "sec=", 4) == 0) { + if (strncmp(tkn + 4, "krb5", 4) == 0) { + retval |= DKD_HAVE_SEC; + *sec = KRB5; + } else if (strncmp(tkn + 4, "mskrb5", 6) == 0) { + retval |= DKD_HAVE_SEC; + *sec = MS_KRB5; + } + } else if (strncmp(tkn, "uid=", 4) == 0) { + errno = 0; + *uid = strtol(tkn + 4, NULL, 16); + if (errno != 0) { + syslog(LOG_WARNING, "Invalid uid format: %s", + strerror(errno)); + return 1; + } else { + retval |= DKD_HAVE_UID; + } + } else if (strncmp(tkn, "ver=", 4) == 0) { /* if version */ + errno = 0; + *ver = strtol(tkn + 4, NULL, 16); + if (errno != 0) { + syslog(LOG_WARNING, + "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_WARNING, "invalid key description: %s", + key_descr); + return 1; + } + } + keyend++; + + /* resolve name to ip */ + c = getaddrinfo(keyend, NULL, NULL, &addr); + if (c) { + syslog(LOG_WARNING, "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_WARNING, "%s: inet_ntop: %s", + __FUNCTION__, strerror(errno)); + freeaddrinfo(addr); + return 1; + } + + /* setup key */ + c = keyctl_instantiate(key, ip, strlen(ip)+1, 0); + if (c == -1) { + syslog(LOG_WARNING, "%s: keyctl_instantiate: %s", + __FUNCTION__, strerror(errno)); + freeaddrinfo(addr); + return 1; + } + + freeaddrinfo(addr); + return 0; +} + +static void +usage(void) +{ + syslog(LOG_WARNING, "Usage: %s [-c] [-v] key_serial", prog); + fprintf(stderr, "Usage: %s [-c] [-v] key_serial\n", prog); +} + +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; + secType_t sectype = NONE; + key_serial_t key = 0; + size_t datalen; + long rc = 1; + uid_t uid = 0; + int kernel_upcall_version = 0; + int c, use_cifs_service_prefix = 0; + char *buf, *hostname = NULL; + const char *oid; + + openlog(prog, 0, LOG_DAEMON); + + while ((c = getopt(argc, argv, "cv")) != -1) { + switch (c) { + case 'c':{ + use_cifs_service_prefix = 1; + break; + } + case 'v':{ + printf("version: %s\n", CIFSSPNEGO_VERSION); + goto out; + } + default:{ + syslog(LOG_WARNING, "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_WARNING, "Invalid key format: %s", strerror(errno)); + goto out; + } + + rc = keyctl_describe_alloc(key, &buf); + if (rc == -1) { + syslog(LOG_WARNING, "keyctl_describe_alloc failed: %s", + strerror(errno)); + rc = 1; + goto out; + } + + 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; + } + + rc = decode_key_description(buf, &kernel_upcall_version, §ype, + &hostname, &uid); + if ((rc & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) { + syslog(LOG_WARNING, + "unable to get from description necessary params"); + rc = 1; + SAFE_FREE(buf); + goto out; + } + SAFE_FREE(buf); + + if (kernel_upcall_version > CIFS_SPNEGO_UPCALL_VERSION) { + syslog(LOG_WARNING, + "incompatible kernel upcall version: 0x%x", + kernel_upcall_version); + rc = 1; + goto out; + } + + if (rc & DKD_HAVE_UID) { + rc = setuid(uid); + if (rc == -1) { + syslog(LOG_WARNING, "setuid: %s", strerror(errno)); + goto out; + } + } + + /* BB: someday upcall SPNEGO blob could be checked here to decide + * what mech to use */ + + // do mech specific authorization + switch (sectype) { + case MS_KRB5: + case KRB5:{ + char *princ; + size_t len; + + /* for "cifs/" service name + terminating 0 */ + len = strlen(hostname) + 5 + 1; + princ = SMB_XMALLOC_ARRAY(char, len); + if (!princ) { + rc = 1; + break; + } + if (use_cifs_service_prefix) { + strlcpy(princ, "cifs/", len); + } else { + strlcpy(princ, "host/", len); + } + strlcpy(princ + 5, hostname, len - 5); + + if (sectype == MS_KRB5) + oid = OID_KERBEROS5_OLD; + else + oid = OID_KERBEROS5; + + rc = handle_krb5_mech(oid, princ, &secblob, &sess_key); + SAFE_FREE(princ); + break; + } + default:{ + syslog(LOG_WARNING, "sectype: %d is not implemented", + sectype); + rc = 1; + break; + } + } + + 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 = kernel_upcall_version; + 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_WARNING, "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(hostname); + SAFE_FREE(keydata); + return rc; +} |