Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 648 insertions, 0 deletions

diff --git a/source4/auth/kerberos/kerberos_util.c b/source4/auth/kerberos/kerberos_util.c
new file mode 100644
index 0000000..c14d8c7
--- /dev/null
+++ b/source4/auth/kerberos/kerberos_util.c
@@ -0,0 +1,648 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Kerberos utility functions for GENSEC
+   
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
+
+   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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "system/kerberos.h"
+#include "auth/kerberos/kerberos.h"
+#include "auth/credentials/credentials.h"
+#include "auth/credentials/credentials_krb5.h"
+#include "auth/kerberos/kerberos_credentials.h"
+#include "auth/kerberos/kerberos_util.h"
+
+struct principal_container {
+	struct smb_krb5_context *smb_krb5_context;
+	krb5_principal principal;
+	const char *string_form; /* Optional */
+};
+
+static krb5_error_code free_principal(struct principal_container *pc)
+{
+	/* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
+	krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
+
+	return 0;
+}
+
+
+static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
+				       const char *princ_string,
+				       struct smb_krb5_context *smb_krb5_context,
+				       krb5_principal *princ,
+				       const char **error_string)
+{
+	int ret;
+	struct principal_container *mem_ctx;
+	if (princ_string == NULL) {
+		 *princ = NULL;
+		 return 0;
+	}
+
+	ret = krb5_parse_name(smb_krb5_context->krb5_context,
+			      princ_string, princ);
+
+	if (ret) {
+		(*error_string) = smb_get_krb5_error_message(
+						smb_krb5_context->krb5_context,
+						ret, parent_ctx);
+		return ret;
+	}
+
+	mem_ctx = talloc(parent_ctx, struct principal_container);
+	if (!mem_ctx) {
+		(*error_string) = error_message(ENOMEM);
+		return ENOMEM;
+	}
+
+	/* This song-and-dance effectivly puts the principal
+	 * into talloc, so we can't loose it. */
+	mem_ctx->smb_krb5_context = talloc_reference(mem_ctx,
+						     smb_krb5_context);
+	mem_ctx->principal = *princ;
+	talloc_set_destructor(mem_ctx, free_principal);
+	return 0;
+}
+
+/* Obtain the principal set on this context.  Requires a
+ * smb_krb5_context because we are doing krb5 principal parsing with
+ * the library routines.  The returned princ is placed in the talloc
+ * system by means of a destructor (do *not* free). */
+
+krb5_error_code principal_from_credentials(TALLOC_CTX *parent_ctx,
+				struct cli_credentials *credentials,
+				struct smb_krb5_context *smb_krb5_context,
+				krb5_principal *princ,
+				enum credentials_obtained *obtained,
+				const char **error_string)
+{
+	krb5_error_code ret;
+	const char *princ_string;
+	TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
+	*obtained = CRED_UNINITIALISED;
+
+	if (!mem_ctx) {
+		(*error_string) = error_message(ENOMEM);
+		return ENOMEM;
+	}
+	princ_string = cli_credentials_get_principal_and_obtained(credentials,
+								  mem_ctx,
+								  obtained);
+	if (!princ_string) {
+		*princ = NULL;
+		return 0;
+	}
+
+	ret = parse_principal(parent_ctx, princ_string,
+			      smb_krb5_context, princ, error_string);
+	talloc_free(mem_ctx);
+	return ret;
+}
+
+/* Obtain the principal set on this context.  Requires a
+ * smb_krb5_context because we are doing krb5 principal parsing with
+ * the library routines.  The returned princ is placed in the talloc
+ * system by means of a destructor (do *not* free). */
+
+static krb5_error_code impersonate_principal_from_credentials(
+				TALLOC_CTX *parent_ctx,
+				struct cli_credentials *credentials,
+				struct smb_krb5_context *smb_krb5_context,
+				krb5_principal *princ,
+				const char **error_string)
+{
+	return parse_principal(parent_ctx,
+			cli_credentials_get_impersonate_principal(credentials),
+			smb_krb5_context, princ, error_string);
+}
+
+krb5_error_code smb_krb5_create_principals_array(TALLOC_CTX *mem_ctx,
+						 krb5_context context,
+						 const char *account_name,
+						 const char *realm,
+						 uint32_t num_spns,
+						 const char *spns[],
+						 uint32_t *pnum_principals,
+						 krb5_principal **pprincipals,
+						 const char **error_string)
+{
+	krb5_error_code code;
+	TALLOC_CTX *tmp_ctx;
+	uint32_t num_principals = 0;
+	krb5_principal *principals;
+	uint32_t i;
+
+	tmp_ctx = talloc_new(mem_ctx);
+	if (tmp_ctx == NULL) {
+		*error_string = "Cannot allocate tmp_ctx";
+		return ENOMEM;
+	}
+
+	if (realm == NULL) {
+		*error_string = "Cannot create principal without a realm";
+		code = EINVAL;
+		goto done;
+	}
+
+	if (account_name == NULL && (num_spns == 0 || spns == NULL)) {
+		*error_string = "Cannot create principal without an account or SPN";
+		code = EINVAL;
+		goto done;
+	}
+
+	if (account_name != NULL && account_name[0] != '\0') {
+		num_principals++;
+	}
+	num_principals += num_spns;
+
+	principals = talloc_zero_array(tmp_ctx,
+				       krb5_principal,
+				       num_principals);
+	if (principals == NULL) {
+		*error_string = "Cannot allocate principals";
+		code = ENOMEM;
+		goto done;
+	}
+
+	for (i = 0; i < num_spns; i++) {
+		code = krb5_parse_name(context, spns[i], &(principals[i]));
+		if (code != 0) {
+			*error_string = smb_get_krb5_error_message(context,
+								   code,
+								   mem_ctx);
+			goto done;
+		}
+	}
+
+	if (account_name != NULL && account_name[0] != '\0') {
+		code = smb_krb5_make_principal(context,
+					       &(principals[i]),
+					       realm,
+					       account_name,
+					       NULL);
+		if (code != 0) {
+			*error_string = smb_get_krb5_error_message(context,
+								   code,
+								   mem_ctx);
+			goto done;
+		}
+	}
+
+	if (pnum_principals != NULL) {
+		*pnum_principals = num_principals;
+
+		if (pprincipals != NULL) {
+			*pprincipals = talloc_steal(mem_ctx, principals);
+		}
+	}
+
+	code = 0;
+done:
+	talloc_free(tmp_ctx);
+	return code;
+}
+
+/**
+ * Return a freshly allocated ccache (destroyed by destructor on child
+ * of parent_ctx), for a given set of client credentials 
+ */
+
+ krb5_error_code kinit_to_ccache(TALLOC_CTX *parent_ctx,
+				 struct cli_credentials *credentials,
+				 struct smb_krb5_context *smb_krb5_context,
+				 struct tevent_context *event_ctx,
+				 krb5_ccache ccache,
+				 enum credentials_obtained *obtained,
+				 const char **error_string)
+{
+	krb5_error_code ret;
+	const char *password;
+	const char *self_service;
+	const char *target_service;
+	time_t kdc_time = 0;
+	krb5_principal princ;
+	krb5_principal impersonate_principal;
+	int tries;
+	TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
+	krb5_get_init_creds_opt *krb_options;
+
+	if (!mem_ctx) {
+		(*error_string) = strerror(ENOMEM);
+		return ENOMEM;
+	}
+
+	ret = principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &princ, obtained, error_string);
+	if (ret) {
+		talloc_free(mem_ctx);
+		return ret;
+	}
+
+	if (princ == NULL) {
+		(*error_string) = talloc_asprintf(credentials, "principal, username or realm was not specified in the credentials");
+		talloc_free(mem_ctx);
+		return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
+	}
+
+	ret = impersonate_principal_from_credentials(mem_ctx, credentials, smb_krb5_context, &impersonate_principal, error_string);
+	if (ret) {
+		talloc_free(mem_ctx);
+		return ret;
+	}
+
+	self_service = cli_credentials_get_self_service(credentials);
+	target_service = cli_credentials_get_target_service(credentials);
+
+	password = cli_credentials_get_password(credentials);
+
+	/* setup the krb5 options we want */
+	if ((ret = krb5_get_init_creds_opt_alloc(smb_krb5_context->krb5_context, &krb_options))) {
+		(*error_string) = talloc_asprintf(credentials, "krb5_get_init_creds_opt_alloc failed (%s)\n",
+						  smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+									     ret, mem_ctx));
+		talloc_free(mem_ctx);
+		return ret;
+	}
+
+#ifdef SAMBA4_USES_HEIMDAL /* Disable for now MIT reads defaults when needed */
+	/* get the defaults */
+	krb5_get_init_creds_opt_set_default_flags(smb_krb5_context->krb5_context, NULL, NULL, krb_options);
+#endif
+	/* set if we want a forwardable ticket */
+	switch (cli_credentials_get_krb_forwardable(credentials)) {
+	case CRED_AUTO_KRB_FORWARDABLE:
+		break;
+	case CRED_NO_KRB_FORWARDABLE:
+		krb5_get_init_creds_opt_set_forwardable(krb_options, FALSE);
+		break;
+	case CRED_FORCE_KRB_FORWARDABLE:
+		krb5_get_init_creds_opt_set_forwardable(krb_options, TRUE);
+		break;
+	}
+
+#ifdef SAMBA4_USES_HEIMDAL /* FIXME: MIT does not have this yet */
+	/*
+	 * In order to work against windows KDCs even if we use
+	 * the netbios domain name as realm, we need to add the following
+	 * flags:
+	 * KRB5_INIT_CREDS_NO_C_CANON_CHECK;
+	 * KRB5_INIT_CREDS_NO_C_NO_EKU_CHECK;
+	 *
+	 * On MIT: Set pkinit_eku_checking to none
+	 */
+	krb5_get_init_creds_opt_set_win2k(smb_krb5_context->krb5_context,
+					  krb_options, true);
+	krb5_get_init_creds_opt_set_canonicalize(smb_krb5_context->krb5_context,
+						 krb_options, true);
+#else /* MIT */
+	krb5_get_init_creds_opt_set_canonicalize(krb_options, true);
+#endif
+
+	tries = 2;
+	while (tries--) {
+#ifdef SAMBA4_USES_HEIMDAL
+		struct tevent_context *previous_ev;
+		/* Do this every time, in case we have weird recursive issues here */
+		ret = smb_krb5_context_set_event_ctx(smb_krb5_context, event_ctx, &previous_ev);
+		if (ret) {
+			talloc_free(mem_ctx);
+			return ret;
+		}
+#endif
+		if (password) {
+			if (impersonate_principal) {
+				ret = smb_krb5_kinit_s4u2_ccache(smb_krb5_context->krb5_context,
+								 ccache,
+								 princ,
+								 password,
+								 impersonate_principal,
+								 self_service,
+								 target_service,
+								 krb_options,
+								 NULL,
+								 &kdc_time);
+			} else {
+				ret = smb_krb5_kinit_password_ccache(smb_krb5_context->krb5_context,
+								     ccache,
+								     princ,
+								     password,
+								     target_service,
+								     krb_options,
+								     NULL,
+								     &kdc_time);
+			}
+		} else if (impersonate_principal) {
+			talloc_free(mem_ctx);
+			(*error_string) = "INTERNAL error: Cannot impersonate principal with just a keyblock.  A password must be specified in the credentials";
+			return EINVAL;
+		} else {
+			/* No password available, try to use a keyblock instead */
+			
+			krb5_keyblock keyblock;
+			const struct samr_Password *mach_pwd;
+			mach_pwd = cli_credentials_get_nt_hash(credentials, mem_ctx);
+			if (!mach_pwd) {
+				talloc_free(mem_ctx);
+				(*error_string) = "kinit_to_ccache: No password available for kinit\n";
+				krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
+#ifdef SAMBA4_USES_HEIMDAL
+				smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
+#endif
+				return EINVAL;
+			}
+			ret = smb_krb5_keyblock_init_contents(smb_krb5_context->krb5_context,
+						 ENCTYPE_ARCFOUR_HMAC,
+						 mach_pwd->hash, sizeof(mach_pwd->hash), 
+						 &keyblock);
+			
+			if (ret == 0) {
+				ret = smb_krb5_kinit_keyblock_ccache(smb_krb5_context->krb5_context,
+								     ccache,
+								     princ,
+								     &keyblock,
+								     target_service,
+								     krb_options,
+								     NULL,
+								     &kdc_time);
+				krb5_free_keyblock_contents(smb_krb5_context->krb5_context, &keyblock);
+			}
+		}
+
+#ifdef SAMBA4_USES_HEIMDAL
+		smb_krb5_context_remove_event_ctx(smb_krb5_context, previous_ev, event_ctx);
+#endif
+
+		if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
+			/* Perhaps we have been given an invalid skew, so try again without it */
+			time_t t = time(NULL);
+			krb5_set_real_time(smb_krb5_context->krb5_context, t, 0);
+		} else {
+			/* not a skew problem */
+			break;
+		}
+	}
+
+	krb5_get_init_creds_opt_free(smb_krb5_context->krb5_context, krb_options);
+
+	if (ret == KRB5KRB_AP_ERR_SKEW || ret == KRB5_KDCREP_SKEW) {
+		(*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
+						  cli_credentials_get_principal(credentials, mem_ctx),
+						  smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+									     ret, mem_ctx));
+		talloc_free(mem_ctx);
+		return ret;
+	}
+
+	/* cope with ticket being in the future due to clock skew */
+	if ((unsigned)kdc_time > time(NULL)) {
+		time_t t = time(NULL);
+		int time_offset =(unsigned)kdc_time-t;
+		DEBUG(4,("Advancing clock by %d seconds to cope with clock skew\n", time_offset));
+		krb5_set_real_time(smb_krb5_context->krb5_context, t + time_offset + 1, 0);
+	}
+	
+	if (ret == KRB5KDC_ERR_PREAUTH_FAILED && cli_credentials_wrong_password(credentials)) {
+		ret = kinit_to_ccache(parent_ctx,
+				      credentials,
+				      smb_krb5_context,
+				      event_ctx,
+				      ccache, obtained,
+				      error_string);
+	}
+
+	if (ret) {
+		(*error_string) = talloc_asprintf(credentials, "kinit for %s failed (%s)\n",
+						  cli_credentials_get_principal(credentials, mem_ctx),
+						  smb_get_krb5_error_message(smb_krb5_context->krb5_context,
+									     ret, mem_ctx));
+		talloc_free(mem_ctx);
+		return ret;
+	}
+
+	DEBUG(10,("kinit for %s succeeded\n",
+		cli_credentials_get_principal(credentials, mem_ctx)));
+
+
+	talloc_free(mem_ctx);
+	return 0;
+}
+
+static krb5_error_code free_keytab_container(struct keytab_container *ktc)
+{
+	return krb5_kt_close(ktc->smb_krb5_context->krb5_context, ktc->keytab);
+}
+
+krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
+				struct smb_krb5_context *smb_krb5_context,
+				krb5_keytab opt_keytab,
+				const char *keytab_name,
+				struct keytab_container **ktc)
+{
+	krb5_keytab keytab;
+	krb5_error_code ret;
+
+	if (opt_keytab) {
+		keytab = opt_keytab;
+	} else {
+		ret = krb5_kt_resolve(smb_krb5_context->krb5_context,
+						keytab_name, &keytab);
+		if (ret) {
+			DEBUG(1,("failed to open krb5 keytab: %s\n",
+				 smb_get_krb5_error_message(
+					smb_krb5_context->krb5_context,
+					ret, mem_ctx)));
+			return ret;
+		}
+	}
+
+	*ktc = talloc(mem_ctx, struct keytab_container);
+	if (!*ktc) {
+		return ENOMEM;
+	}
+
+	(*ktc)->smb_krb5_context = talloc_reference(*ktc, smb_krb5_context);
+	(*ktc)->keytab = keytab;
+	(*ktc)->password_based = false;
+	talloc_set_destructor(*ktc, free_keytab_container);
+
+	return 0;
+}
+
+/*
+ * Walk the keytab, looking for entries of this principal name,
+ * with KVNO other than current kvno -1.
+ *
+ * These entries are now stale,
+ * we only keep the current and previous entries around.
+ *
+ * Inspired by the code in Samba3 for 'use kerberos keytab'.
+ */
+krb5_error_code smb_krb5_remove_obsolete_keytab_entries(TALLOC_CTX *mem_ctx,
+							krb5_context context,
+							krb5_keytab keytab,
+							uint32_t num_principals,
+							krb5_principal *principals,
+							krb5_kvno kvno,
+							bool *found_previous,
+							const char **error_string)
+{
+	TALLOC_CTX *tmp_ctx;
+	krb5_error_code code;
+	krb5_kt_cursor cursor;
+
+	tmp_ctx = talloc_new(mem_ctx);
+	if (tmp_ctx == NULL) {
+		*error_string = "Cannot allocate tmp_ctx";
+		return ENOMEM;
+	}
+
+	*found_previous = true;
+
+	code = krb5_kt_start_seq_get(context, keytab, &cursor);
+	switch (code) {
+	case 0:
+		break;
+#ifdef HEIM_ERR_OPNOTSUPP
+	case HEIM_ERR_OPNOTSUPP:
+#endif
+	case ENOENT:
+	case KRB5_KT_END:
+		/* no point enumerating if there isn't anything here */
+		code = 0;
+		goto done;
+	default:
+		*error_string = talloc_asprintf(mem_ctx,
+						"failed to open keytab for read of old entries: %s\n",
+						smb_get_krb5_error_message(context, code, mem_ctx));
+		goto done;
+	}
+
+	do {
+		krb5_kvno old_kvno = kvno - 1;
+		krb5_keytab_entry entry;
+		bool matched = false;
+		uint32_t i;
+
+		code = krb5_kt_next_entry(context, keytab, &entry, &cursor);
+		if (code) {
+			break;
+		}
+
+		for (i = 0; i < num_principals; i++) {
+			krb5_boolean ok;
+
+			ok = smb_krb5_kt_compare(context,
+						&entry,
+						principals[i],
+						0,
+						0);
+			if (ok) {
+				matched = true;
+				break;
+			}
+		}
+
+		if (!matched) {
+			/*
+			 * Free the entry, it wasn't the one we were looking
+			 * for anyway
+			 */
+			krb5_kt_free_entry(context, &entry);
+			/* Make sure we do not double free */
+			ZERO_STRUCT(entry);
+			continue;
+		}
+
+		/*
+		 * Delete it, if it is not kvno - 1.
+		 *
+		 * Some keytab files store the kvno only in 8bits. Limit the
+		 * compare to 8bits, so that we don't miss old keys and delete
+		 * them.
+		 */
+		if ((entry.vno & 0xff) != (old_kvno & 0xff)) {
+			krb5_error_code rc;
+
+			/* Release the enumeration.  We are going to
+			 * have to start this from the top again,
+			 * because deletes during enumeration may not
+			 * always be consistent.
+			 *
+			 * Also, the enumeration locks a FILE: keytab
+			 */
+			krb5_kt_end_seq_get(context, keytab, &cursor);
+
+			code = krb5_kt_remove_entry(context, keytab, &entry);
+			krb5_kt_free_entry(context, &entry);
+
+			/* Make sure we do not double free */
+			ZERO_STRUCT(entry);
+
+			/* Deleted: Restart from the top */
+			rc = krb5_kt_start_seq_get(context, keytab, &cursor);
+			if (rc != 0) {
+				krb5_kt_free_entry(context, &entry);
+
+				/* Make sure we do not double free */
+				ZERO_STRUCT(entry);
+
+				DEBUG(1, ("failed to restart enumeration of keytab: %s\n",
+					  smb_get_krb5_error_message(context,
+								     code,
+								     tmp_ctx)));
+
+				talloc_free(tmp_ctx);
+				return rc;
+			}
+
+			if (code != 0) {
+				break;
+			}
+
+		} else {
+			*found_previous = true;
+		}
+
+		/* Free the entry, we don't need it any more */
+		krb5_kt_free_entry(context, &entry);
+		/* Make sure we do not double free */
+		ZERO_STRUCT(entry);
+	} while (code == 0);
+
+	krb5_kt_end_seq_get(context, keytab, &cursor);
+
+	switch (code) {
+	case 0:
+		break;
+	case ENOENT:
+	case KRB5_KT_END:
+		break;
+	default:
+		*error_string = talloc_asprintf(mem_ctx,
+						"failed in deleting old entries for principal: %s\n",
+						smb_get_krb5_error_message(context,
+									   code,
+									   mem_ctx));
+	}
+
+	code = 0;
+done:
+	talloc_free(tmp_ctx);
+	return code;
+}