r7058: Add experimenthal pam authentication for web pages

(This used to be commit 36d905407465cb9d8950da86322531e3c3102642)

4 files changed, 426 insertions, 3 deletions

diff --git a/source4/web_server/calls.c b/source4/web_server/calls.c
index fc23a113fe..ab20c38193 100644
--- a/source4/web_server/calls.c
+++ b/source4/web_server/calls.c
@@ -21,11 +21,11 @@
 */
 
 #include "includes.h"
+#include "pwd.h"
 #include "web_server/esp/esp.h"
 #include "param/loadparm.h"
 #include "lib/ldb/include/ldb.h"
 
-
 /*
   add an indexed array element to a property
 */
@@ -378,6 +378,74 @@ failed:
 	return -1;
 }
 
+/* try to authenticate the user/password pair against system auth mechanisms
+   returns 0 on success
+   returns -1 on error
+
+   fills in the session structure properly in case of success
+   NOTE: Currently only PAM Auth is supported
+*/
+
+static int esp_unixAuth(struct EspRequest *ep, int argc, struct MprVar **argv)
+{
+	TALLOC_CTX *tmp_ctx = talloc_new(ep);
+	const char *username;
+	const char *password;
+	struct passwd *pwd;
+	int ret;
+
+	if (argc != 2 || argv[0]->type != MPR_TYPE_STRING ||
+			argv[1]->type != MPR_TYPE_STRING) {
+		espError(ep, "unixAuth invalid arguments");
+		ret = -1;
+		goto done;
+	}
+
+	username = mprToString(argv[0]);
+	password = mprToString(argv[1]);
+
+	if (username == NULL || password == NULL) {
+		espError(ep, "unixAuth invalid arguments");
+		ret = -1;
+		goto done;
+	}
+
+	/* TODO: find out how to pass the real client name/address here */
+	if (NT_STATUS_IS_OK(unix_passcheck(tmp_ctx, "client", username, password))) {
+
+		pwd = getpwnam(username);
+		if (!pwd) {
+			espSetReturn(ep, mprCreateIntegerVar(-1));
+			ret = -1;
+			goto done;
+		}
+
+		mprSetPropertyValue(&ep->variables[ESP_SESSION_OBJ],
+					"AUTHENTICATED", mprCreateStringVar("1", 0));
+		mprSetPropertyValue(&ep->variables[ESP_SESSION_OBJ],
+					"USERNAME", mprCreateStringVar(username, 0));
+
+		if (pwd->pw_uid == 0) { /* we are root */
+
+			mprSetPropertyValue(&ep->variables[ESP_SESSION_OBJ],
+					"PRIVILEGE", mprCreateStringVar("ADMIN", 0));
+		} else {
+			mprSetPropertyValue(&ep->variables[ESP_SESSION_OBJ],
+					"PRIVILEGE", mprCreateStringVar("USER", 0));
+		}
+
+		espSetReturn(ep, mprCreateIntegerVar(0));
+	} else {
+		if (mprGetProperty(&ep->variables[ESP_SESSION_OBJ], "AUTHENTICATED", 0) != 0) {
+			mprDeleteProperty(&ep->variables[ESP_SESSION_OBJ], "AUTHENTICATED");
+		}
+		espSetReturn(ep, mprCreateIntegerVar(-1));
+	}
+
+done:
+	talloc_free(tmp_ctx);
+	return ret;
+}
 
 /*
   setup the C functions that be called from ejs
@@ -388,4 +456,5 @@ void http_setup_ejs_functions(void)
 	espDefineStringCFunction(NULL, "lpServices", esp_lpServices, NULL);
 	espDefineCFunction(NULL, "typeof", esp_typeof, NULL);
 	espDefineCFunction(NULL, "ldbSearch", esp_ldbSearch, NULL);
+	espDefineCFunction(NULL, "unixAuth", esp_unixAuth, NULL);
 }
diff --git a/source4/web_server/config.m4 b/source4/web_server/config.m4
index 057f193179..7adbfb1721 100644
--- a/source4/web_server/config.m4
+++ b/source4/web_server/config.m4
@@ -11,3 +11,15 @@ fi
 SMB_EXT_LIB(GNUTLS, $GNUTLS_LIBS)
 # end SMB_EXT_LIB_GNUTLS
 ###############################
+
+###############################
+# start SMB_EXT_LIB_PAM
+# check for security/pam_appl.h and -lpam
+AC_CHECK_HEADERS(security/pam_appl.h)
+AC_CHECK_LIB_EXT(pam, PAM_LIBS, pam_start)
+if test x"$ac_cv_header_security_pam_appl_h" = x"yes" -a x"$ac_cv_lib_ext_pam_pam_start" = x"yes";then
+	SMB_EXT_LIB_ENABLE(PAM,YES)
+fi
+SMB_EXT_LIB(PAM, $PAM_LIBS)
+# end SMB_EXT_LIB_PAM
+###############################
diff --git a/source4/web_server/config.mk b/source4/web_server/config.mk
index acaccd7130..bcb5bea0ff 100644
--- a/source4/web_server/config.mk
+++ b/source4/web_server/config.mk
@@ -36,7 +36,8 @@ ADD_OBJ_FILES = \
 		web_server/http.o \
 		web_server/calls.o \
 		web_server/tls.o \
-		web_server/tlscert.o
-REQUIRED_SUBSYSTEMS = ESP EXT_LIB_GNUTLS
+		web_server/tlscert.o \
+		web_server/pam.o
+REQUIRED_SUBSYSTEMS = ESP EXT_LIB_GNUTLS EXT_LIB_PAM
 # End SUBSYSTEM WEB
 #######################
diff --git a/source4/web_server/pam.c b/source4/web_server/pam.c
new file mode 100644
index 0000000000..5ee04a3115
--- /dev/null
+++ b/source4/web_server/pam.c
@@ -0,0 +1,341 @@
+/* 
+   Unix SMB/CIFS implementation.
+   PAM Password checking
+   Copyright (C) Andrew Tridgell 1992-2001
+   Copyright (C) John H Terpsta 1999-2001
+   Copyright (C) Andrew Bartlett 2001
+   Copyright (C) Jeremy Allison 2001
+   Copyright (C) Simo Sorce 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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/*
+ * This module provides PAM based functions for validation of
+ * username/password pairs.
+ * Note: This module is a stripped down version of pampass.c of samba 3
+ *       It has been adapted to perform only pam auth checks and code has
+ *       been shaped out to meet samba4 coding stile
+ */
+
+#include "includes.h"
+
+#ifdef HAVE_SECURITY_PAM_APPL_H
+
+/*******************************************************************
+ * Handle PAM authentication 
+ * 	- Access, Authentication, Session, Password
+ *   Note: See PAM Documentation and refer to local system PAM implementation
+ *   which determines what actions/limitations/allowances become affected.
+ *********************************************************************/
+
+#include <security/pam_appl.h>
+
+/*
+ * Structure used to communicate between the conversation function
+ * and the server_login/change password functions.
+ */
+
+struct smb_pam_userdata {
+	const char *PAM_username;
+	const char *PAM_password;
+};
+
+typedef int (*smb_pam_conv_fn)(int, const struct pam_message **, struct pam_response **, void *appdata_ptr);
+
+/*******************************************************************
+ PAM error handler.
+ *********************************************************************/
+
+static BOOL smb_pam_error_handler(pam_handle_t *pamh, int pam_error, const char *msg, int dbglvl)
+{
+
+	if( pam_error != PAM_SUCCESS) {
+		DEBUG(dbglvl, ("smb_pam_error_handler: PAM: %s : %s\n",
+				msg, pam_strerror(pamh, pam_error)));
+		
+		return False;
+	}
+	return True;
+}
+
+/*******************************************************************
+ This function is a sanity check, to make sure that we NEVER report
+ failure as sucess.
+*********************************************************************/
+
+static BOOL smb_pam_nt_status_error_handler(pam_handle_t *pamh, int pam_error,
+					    const char *msg, int dbglvl, 
+					    NTSTATUS *nt_status)
+{
+	*nt_status = pam_to_nt_status(pam_error);
+
+	if (smb_pam_error_handler(pamh, pam_error, msg, dbglvl))
+		return True;
+
+	if (NT_STATUS_IS_OK(*nt_status)) {
+		/* Complain LOUDLY */
+		DEBUG(0, ("smb_pam_nt_status_error_handler: PAM: BUG: PAM and NT_STATUS \
+error MISMATCH, forcing to NT_STATUS_LOGON_FAILURE"));
+		*nt_status = NT_STATUS_LOGON_FAILURE;
+	}
+	return False;
+}
+
+/*
+ * PAM conversation function
+ * Here we assume (for now, at least) that echo on means login name, and
+ * echo off means password.
+ */
+
+static int smb_pam_conv(int num_msg,
+		    const struct pam_message **msg,
+		    struct pam_response **resp,
+		    void *appdata_ptr)
+{
+	int replies = 0;
+	struct pam_response *reply = NULL;
+	struct smb_pam_userdata *udp = (struct smb_pam_userdata *)appdata_ptr;
+
+	*resp = NULL;
+
+	if (num_msg <= 0)
+		return PAM_CONV_ERR;
+
+	/*
+	 * Apparantly HPUX has a buggy PAM that doesn't support the
+	 * appdata_ptr. Fail if this is the case. JRA.
+	 */
+
+	if (udp == NULL) {
+		DEBUG(0,("smb_pam_conv: PAM on this system is broken - appdata_ptr == NULL !\n"));
+		return PAM_CONV_ERR;
+	}
+
+	reply = malloc_array_p(struct pam_response, num_msg);
+	if (!reply)
+		return PAM_CONV_ERR;
+
+	memset(reply, '\0', sizeof(struct pam_response) * num_msg);
+
+	for (replies = 0; replies < num_msg; replies++) {
+		switch (msg[replies]->msg_style) {
+			case PAM_PROMPT_ECHO_ON:
+				reply[replies].resp_retcode = PAM_SUCCESS;
+				reply[replies].resp = strdup(udp->PAM_username);
+				/* PAM frees resp */
+				break;
+
+			case PAM_PROMPT_ECHO_OFF:
+				reply[replies].resp_retcode = PAM_SUCCESS;
+				reply[replies].resp = strdup(udp->PAM_password);
+				/* PAM frees resp */
+				break;
+
+			case PAM_TEXT_INFO:
+				/* fall through */
+
+			case PAM_ERROR_MSG:
+				/* ignore it... */
+				reply[replies].resp_retcode = PAM_SUCCESS;
+				reply[replies].resp = NULL;
+				break;
+
+			default:
+				/* Must be an error of some sort... */
+				if (reply)
+					free(reply);
+				return PAM_CONV_ERR;
+		}
+	}
+	if (reply)
+		*resp = reply;
+	return PAM_SUCCESS;
+}
+
+/***************************************************************************
+ Allocate a pam_conv struct.
+****************************************************************************/
+
+static struct pam_conv *smb_setup_pam_conv(TALLOC_CTX *ctx,
+					   smb_pam_conv_fn smb_pam_conv_fnptr,
+					   const char *username, const char *password)
+{
+	struct pam_conv *pconv;
+	struct smb_pam_userdata *udp;
+
+	pconv = talloc(ctx, struct pam_conv);
+	if (pconv == NULL)
+		return NULL;
+
+	udp = talloc(ctx, struct smb_pam_userdata);
+	if (udp == NULL)
+		return NULL;
+
+	udp->PAM_username = username;
+	udp->PAM_password = password;
+
+	pconv->conv = smb_pam_conv_fnptr;
+	pconv->appdata_ptr = (void *)udp;
+
+	return pconv;
+}
+
+/* 
+ * PAM Closing out cleanup handler
+ */
+
+static BOOL smb_pam_end(pam_handle_t *pamh, struct pam_conv *smb_pam_conv_ptr)
+{
+	int pam_error;
+
+	if( pamh != NULL ) {
+		pam_error = pam_end(pamh, 0);
+		if(smb_pam_error_handler(pamh, pam_error, "End Cleanup Failed", 2) == True) {
+			DEBUG(4, ("smb_pam_end: PAM: PAM_END OK.\n"));
+			return True;
+		}
+	}
+	DEBUG(2,("smb_pam_end: PAM: not initialised"));
+	return False;
+}
+
+/*
+ * Start PAM authentication for specified account
+ */
+
+static BOOL smb_pam_start(pam_handle_t **pamh, const char *user, const char *rhost, struct pam_conv *pconv)
+{
+	int pam_error;
+	const char *our_rhost;
+
+	if (user == NULL || rhost == NULL || pconv == NULL) {
+		return False;
+	}
+
+	*pamh = (pam_handle_t *)NULL;
+
+	DEBUG(4,("smb_pam_start: PAM: Init user: %s\n", user));
+
+	pam_error = pam_start("samba", user, pconv, pamh);
+	if( !smb_pam_error_handler(*pamh, pam_error, "Init Failed", 0)) {
+		*pamh = (pam_handle_t *)NULL;
+		return False;
+	}
+
+#ifdef PAM_RHOST
+	DEBUG(4,("smb_pam_start: PAM: setting rhost to: %s\n", rhost));
+	pam_error = pam_set_item(*pamh, PAM_RHOST, rhost);
+	if(!smb_pam_error_handler(*pamh, pam_error, "set rhost failed", 0)) {
+		smb_pam_end(*pamh, pconv);
+		*pamh = (pam_handle_t *)NULL;
+		return False;
+	}
+#endif
+#ifdef PAM_TTY
+	DEBUG(4,("smb_pam_start: PAM: setting tty\n"));
+	pam_error = pam_set_item(*pamh, PAM_TTY, "samba");
+	if (!smb_pam_error_handler(*pamh, pam_error, "set tty failed", 0)) {
+		smb_pam_end(*pamh, pconv);
+		*pamh = (pam_handle_t *)NULL;
+		return False;
+	}
+#endif
+	DEBUG(4,("smb_pam_start: PAM: Init passed for user: %s\n", user));
+	return True;
+}
+
+/*
+ * PAM Authentication Handler
+ */
+static NTSTATUS smb_pam_auth(pam_handle_t *pamh, const char *user)
+{
+	int pam_error;
+	NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
+
+	/*
+	 * To enable debugging set in /etc/pam.d/samba:
+	 *	auth required /lib/security/pam_pwdb.so nullok shadow audit
+	 */
+	
+	DEBUG(4,("smb_pam_auth: PAM: Authenticate User: %s\n", user));
+	pam_error = pam_authenticate(pamh, PAM_SILENT | lp_null_passwords() ? 0 : PAM_DISALLOW_NULL_AUTHTOK);
+	switch( pam_error ){
+		case PAM_AUTH_ERR:
+			DEBUG(2, ("smb_pam_auth: PAM: Athentication Error for user %s\n", user));
+			break;
+		case PAM_CRED_INSUFFICIENT:
+			DEBUG(2, ("smb_pam_auth: PAM: Insufficient Credentials for user %s\n", user));
+			break;
+		case PAM_AUTHINFO_UNAVAIL:
+			DEBUG(2, ("smb_pam_auth: PAM: Authentication Information Unavailable for user %s\n", user));
+			break;
+		case PAM_USER_UNKNOWN:
+			DEBUG(2, ("smb_pam_auth: PAM: Username %s NOT known to Authentication system\n", user));
+			break;
+		case PAM_MAXTRIES:
+			DEBUG(2, ("smb_pam_auth: PAM: One or more authentication modules reports user limit for user %s exceeeded\n", user));
+			break;
+		case PAM_ABORT:
+			DEBUG(0, ("smb_pam_auth: PAM: One or more PAM modules failed to load for user %s\n", user));
+			break;
+		case PAM_SUCCESS:
+			DEBUG(4, ("smb_pam_auth: PAM: User %s Authenticated OK\n", user));
+			break;
+		default:
+			DEBUG(0, ("smb_pam_auth: PAM: UNKNOWN ERROR while authenticating user %s\n", user));
+			break;
+	}
+
+	smb_pam_nt_status_error_handler(pamh, pam_error, "Authentication Failure", 2, &nt_status);
+	return nt_status;
+}
+
+/*
+ * PAM Password Validation Suite
+ */
+
+NTSTATUS unix_passcheck(TALLOC_CTX *ctx, const char *client, const char *username, const char *password)
+{
+	NTSTATUS nt_status = NT_STATUS_LOGON_FAILURE;
+	pam_handle_t *pamh = NULL;
+	struct pam_conv *pconv = NULL;
+
+	if ((pconv = smb_setup_pam_conv(ctx, smb_pam_conv, username, password)) == NULL)
+		return nt_status;
+
+	if (!smb_pam_start(&pamh, username, client, pconv)) {
+		talloc_free(pconv);
+		return nt_status;
+	}
+
+	if (!NT_STATUS_IS_OK(nt_status = smb_pam_auth(pamh, username))) {
+		DEBUG(0, ("smb_pam_passcheck: PAM: smb_pam_auth failed - Rejecting User %s !\n", username));
+	}
+
+	smb_pam_end(pamh, pconv);
+	talloc_free(pconv);
+
+	return nt_status;
+}
+
+#else
+
+NTSTATUS unix_passcheck(TALLOC_CTX *ctx, const char *client, const char *username, const char *password)
+{
+	return NT_STATUS_LOGON_FAILURE;
+}
+
+#endif /* WITH_PAM */