Initial import of files from samba master branch

(commit 6e510b49c03be9caba4f587f3f6cec547841b0d7)

1 files changed, 653 insertions, 0 deletions

diff --git a/cifs.upcall.c b/cifs.upcall.c
new file mode 100644
index 0000000..bfc70d1
--- /dev/null
+++ b/cifs.upcall.c
@@ -0,0 +1,653 @@
+/*
+* 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;
+
+	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;
+	}
+
+	while (!credtime && !krb5_cc_next_cred(context, ccache, &cur, &creds)) {
+		char *name;
+		if (smb_krb5_unparse_name(NULL, 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:
+        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;
+}