/*
* 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
*/
#include "includes.h"
+#include "../libcli/auth/spnego.h"
+#include "smb_krb5.h"
#include <keyutils.h>
+#include <getopt.h>
#include "cifs_spnego.h"
-const char *CIFSSPNEGO_VERSION = "1.2";
+#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 {
+typedef enum _sectype {
NONE = 0,
KRB5,
MS_KRB5
-} secType_t;
+} 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
* 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)
+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, NULL, NULL);
+ retval = cli_krb5_get_ticket(principal, 0, &tkt, sess_key, 0, ccname,
+ NULL, NULL);
- if (retval)
+ 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);
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_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)
-static int
-decode_key_description(const char *desc, int *ver, secType_t * sec,
- char **hostname, uid_t * uid)
+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) {
- int len;
- if (pos == NULL) {
+ if (pos == NULL)
len = strlen(tkn);
- } else {
+ else
len = pos - tkn;
- }
+
len -= 4;
- SAFE_FREE(*hostname);
- *hostname = SMB_XMALLOC_ARRAY(char, len);
- strlcpy(*hostname, tkn + 5, len);
+ 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, "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, "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;
- *sec = KRB5;
+ arg->sec = KRB5;
} else if (strncmp(tkn + 4, "mskrb5", 6) == 0) {
retval |= DKD_HAVE_SEC;
- *sec = MS_KRB5;
+ arg->sec = MS_KRB5;
}
} else if (strncmp(tkn, "uid=", 4) == 0) {
errno = 0;
- *uid = strtol(tkn + 4, NULL, 16);
+ arg->uid = strtol(tkn + 4, NULL, 16);
if (errno != 0) {
- syslog(LOG_WARNING, "Invalid uid format: %s",
+ syslog(LOG_ERR, "Invalid uid format: %s",
strerror(errno));
return 1;
} else {
}
} else if (strncmp(tkn, "ver=", 4) == 0) { /* if version */
errno = 0;
- *ver = strtol(tkn + 4, NULL, 16);
+ arg->ver = strtol(tkn + 4, NULL, 16);
if (errno != 0) {
- syslog(LOG_WARNING,
- "Invalid version format: %s",
+ syslog(LOG_ERR, "Invalid version format: %s",
strerror(errno));
return 1;
} else {
for (c = 1; c <= 4; c++) {
keyend = index(keyend+1, ';');
if (!keyend) {
- syslog(LOG_WARNING, "invalid key description: %s",
+ syslog(LOG_ERR, "invalid key description: %s",
key_descr);
return 1;
}
/* resolve name to ip */
c = getaddrinfo(keyend, NULL, NULL, &addr);
if (c) {
- syslog(LOG_WARNING, "unable to resolve hostname: %s [%s]",
+ 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) {
+ if (addr->ai_family == AF_INET)
p = &(((struct sockaddr_in *)addr->ai_addr)->sin_addr);
- } else {
+ 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));
+ 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_WARNING, "%s: keyctl_instantiate: %s",
- __FUNCTION__, strerror(errno));
+ syslog(LOG_ERR, "%s: keyctl_instantiate: %s", __func__,
+ strerror(errno));
freeaddrinfo(addr);
return 1;
}
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_WARNING, "Usage: %s [-c] [-v] key_serial", prog);
- fprintf(stderr, "Usage: %s [-c] [-v] key_serial\n", prog);
+ 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;
- secType_t sectype = NONE;
key_serial_t key = 0;
size_t datalen;
+ unsigned int have;
long rc = 1;
- uid_t uid = 0;
- int kernel_upcall_version = 0;
- int c, use_cifs_service_prefix = 0;
- char *buf, *hostname = NULL;
+ 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(argc, argv, "cv")) != -1) {
+ while ((c = getopt_long(argc, argv, "ctv", long_options, NULL)) != -1) {
switch (c) {
- case 'c':{
- use_cifs_service_prefix = 1;
+ case 'c':
+ /* legacy option -- skip it */
break;
- }
- case 'v':{
+ case 't':
+ try_dns++;
+ break;
+ case 'v':
printf("version: %s\n", CIFSSPNEGO_VERSION);
goto out;
- }
- default:{
- syslog(LOG_WARNING, "unknown option: %c", c);
+ default:
+ syslog(LOG_ERR, "unknown option: %c", c);
goto out;
- }
}
}
key = strtol(argv[optind], NULL, 10);
if (errno != 0) {
key = 0;
- syslog(LOG_WARNING, "Invalid key format: %s", strerror(errno));
+ syslog(LOG_ERR, "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",
+ 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;
}
- 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");
+ 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;
- 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);
+ if (arg.ver > CIFS_SPNEGO_UPCALL_VERSION) {
+ syslog(LOG_ERR, "incompatible kernel upcall version: 0x%x",
+ arg.ver);
rc = 1;
goto out;
}
- if (rc & DKD_HAVE_UID) {
- rc = setuid(uid);
+ if (have & DKD_HAVE_UID) {
+ rc = setuid(arg.uid);
if (rc == -1) {
- syslog(LOG_WARNING, "setuid: %s", strerror(errno));
+ syslog(LOG_ERR, "setuid: %s", strerror(errno));
goto out;
}
+
+ ccname = find_krb5_cc(CIFS_DEFAULT_KRB5_DIR, arg.uid);
}
- /* BB: someday upcall SPNEGO blob could be checked here to decide
- * what mech to use */
+ host = arg.hostname;
// do mech specific authorization
- switch (sectype) {
+ switch (arg.sec) {
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);
+ 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 (sectype == MS_KRB5)
- oid = OID_KERBEROS5_OLD;
- else
- oid = OID_KERBEROS5;
+ 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;
- rc = handle_krb5_mech(oid, princ, &secblob, &sess_key);
- SAFE_FREE(princ);
+ memcpy(princ, "host/", 5);
+ rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname);
+ if (!rc)
break;
- }
- default:{
- syslog(LOG_WARNING, "sectype: %d is not implemented",
- sectype);
- rc = 1;
+
+ 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;
}
- if (rc) {
+ SAFE_FREE(princ);
+
+ if (rc)
goto out;
- }
/* pack SecurityBLob and SessionKey into downcall packet */
datalen =
rc = 1;
goto out;
}
- keydata->version = kernel_upcall_version;
+ keydata->version = arg.ver;
keydata->flags = 0;
keydata->sesskey_len = sess_key.length;
keydata->secblob_len = secblob.length;
/* setup key */
rc = keyctl_instantiate(key, keydata, datalen, 0);
if (rc == -1) {
- syslog(LOG_WARNING, "keyctl_instantiate: %s", strerror(errno));
+ syslog(LOG_ERR, "keyctl_instantiate: %s", strerror(errno));
goto out;
}
keyctl_negate(key, 1, KEY_REQKEY_DEFL_DEFAULT);
data_blob_free(&secblob);
data_blob_free(&sess_key);
- SAFE_FREE(hostname);
+ SAFE_FREE(ccname);
+ SAFE_FREE(arg.hostname);
+ SAFE_FREE(arg.ip);
SAFE_FREE(keydata);
return rc;
}
git.samba.org / samba.git / blobdiff