From ea488580c42e8918445a945484de3c8a5addc761 Mon Sep 17 00:00:00 2001
From: "Andrew G. Morgan" <morgan@kernel.org>
Date: Tue, 20 Jun 2000 22:10:38 +0000
Subject: Initial revision

---
 modules/pam_ftp/pam_ftp.c | 299 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 299 insertions(+)
 create mode 100644 modules/pam_ftp/pam_ftp.c

(limited to 'modules/pam_ftp/pam_ftp.c')

diff --git a/modules/pam_ftp/pam_ftp.c b/modules/pam_ftp/pam_ftp.c
new file mode 100644
index 00000000..eb2c3fd9
--- /dev/null
+++ b/modules/pam_ftp/pam_ftp.c
@@ -0,0 +1,299 @@
+/* pam_ftp module */
+
+/*
+ * $Id$
+ *
+ * Written by Andrew Morgan <morgan@linux.kernel.org> 1996/3/11
+ *
+ */
+
+#define PLEASE_ENTER_PASSWORD "Password required for %s."
+#define GUEST_LOGIN_PROMPT "Guest login ok, " \
+"send your complete e-mail address as password."
+
+/* the following is a password that "can't be correct" */
+#define BLOCK_PASSWORD "\177BAD PASSWPRD\177"
+
+#define _GNU_SOURCE
+#define _BSD_SOURCE
+
+#include <features.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <stdarg.h>
+#include <string.h>
+
+/*
+ * here, we make a definition for the externally accessible function
+ * in this file (this definition is required for static a module
+ * but strongly encouraged generally) it is used to instruct the
+ * modules include file to define the function prototypes.
+ */
+
+#define PAM_SM_AUTH
+
+#include <security/pam_modules.h>
+#include <security/_pam_macros.h>
+
+/* some syslogging */
+
+static void _pam_log(int err, const char *format, ...)
+{
+    va_list args;
+
+    va_start(args, format);
+    openlog("PAM-ftp", LOG_CONS|LOG_PID, LOG_AUTH);
+    vsyslog(err, format, args);
+    va_end(args);
+    closelog();
+}
+
+static int converse(pam_handle_t *pamh, int nargs
+		    , struct pam_message **message
+		    , struct pam_response **response)
+{
+    int retval;
+    struct pam_conv *conv;
+
+    D(("begin to converse\n"));
+
+    retval = pam_get_item( pamh, PAM_CONV, (const void **) &conv ) ; 
+    if ( retval == PAM_SUCCESS ) {
+
+	retval = conv->conv(nargs, ( const struct pam_message ** ) message
+			    , response, conv->appdata_ptr);
+
+	D(("returned from application's conversation function\n"));
+
+	if ((retval != PAM_SUCCESS) && (retval != PAM_CONV_AGAIN)) {
+	    _pam_log(LOG_DEBUG, "conversation failure [%s]"
+		     , pam_strerror(pamh, retval));
+	}
+
+    } else {
+	_pam_log(LOG_ERR, "couldn't obtain coversation function [%s]"
+		 , pam_strerror(pamh, retval));
+    }
+
+    D(("ready to return from module conversation\n"));
+
+    return retval;                  /* propagate error status */
+}
+
+/* argument parsing */
+
+#define PAM_DEBUG_ARG       01
+#define PAM_IGNORE_EMAIL    02
+#define PAM_NO_ANON         04
+
+static int _pam_parse(int argc, const char **argv, char **users)
+{
+    int ctrl=0;
+
+    /* step through arguments */
+    for (ctrl=0; argc-- > 0; ++argv) {
+
+	/* generic options */
+
+	if (!strcmp(*argv,"debug"))
+	    ctrl |= PAM_DEBUG_ARG;
+	else if (!strncmp(*argv,"users=",6)) {
+	    *users = x_strdup(6+*argv);
+	    if (*users == NULL) {
+		ctrl |= PAM_NO_ANON;
+		_pam_log(LOG_CRIT, "failed to duplicate user list - anon off");
+	    }
+	} else if (!strcmp(*argv,"ignore")) {
+	    ctrl |= PAM_IGNORE_EMAIL;
+	} else {
+	    _pam_log(LOG_ERR,"pam_parse: unknown option; %s",*argv);
+	}
+    }
+
+    return ctrl;
+}
+
+/*
+ * check if name is in list or default list. place users name in *_user
+ * return 1 if listed 0 if not.
+ */
+
+static int lookup(const char *name, char *list, const char **_user)
+{
+    int anon = 0;
+
+    *_user = name;                 /* this is the default */
+    if (list) {
+	const char *l;
+	char *x;
+
+	x = list;
+	while ((l = strtok(x, ","))) {
+	    x = NULL;
+	    if (!strcmp(name, l)) {
+		*_user = list;
+		anon = 1;
+	    }
+	}
+    } else {
+#define MAX_L 2
+	static const char *l[MAX_L] = { "ftp", "anonymous" };
+	int i;
+
+	for (i=0; i<MAX_L; ++i) {
+	    if (!strcmp(l[i], name)) {
+		*_user = l[0];
+		anon = 1;
+		break;
+	    }
+	}
+    }
+
+    return anon;
+}
+
+/* --- authentication management functions (only) --- */
+
+PAM_EXTERN
+int pam_sm_authenticate(pam_handle_t *pamh,int flags,int argc
+			,const char **argv)
+{
+    int retval, anon=0, ctrl;
+    const char *user;
+    char *users=NULL;
+
+    /*
+     * this module checks if the user name is ftp or annonymous. If
+     * this is the case, it can set the PAM_RUSER to the entered email
+     * address and SUCCEEDS, otherwise it FAILS.
+     */
+
+    ctrl = _pam_parse(argc, argv, &users);
+
+    retval = pam_get_user(pamh, &user, NULL);
+    if (retval != PAM_SUCCESS || user == NULL) {
+	_pam_log(LOG_ERR, "no user specified");
+	return PAM_USER_UNKNOWN;
+    }
+
+    if (!(ctrl & PAM_NO_ANON)) {
+	anon = lookup(user, users, &user);
+    }
+
+    if (anon) {
+	retval = pam_set_item(pamh, PAM_USER, (const void *)user);
+	if (retval != PAM_SUCCESS || user == NULL) {
+	    _pam_log(LOG_ERR, "user resetting failed");
+	    return PAM_USER_UNKNOWN;
+	}
+    }
+
+    /*
+     * OK. we require an email address for user or the user's password.
+     * - build conversation and get their input.
+     */
+
+    {
+	struct pam_message msg[1], *mesg[1];
+	struct pam_response *resp=NULL;
+	const char *token;
+	char *prompt=NULL;
+	int i=0;
+
+	if (!anon) {
+	    prompt = malloc(strlen(PLEASE_ENTER_PASSWORD) + strlen(user));
+	    if (prompt == NULL) {
+		D(("out of memory!?"));
+		return PAM_BUF_ERR;
+	    } else {
+		sprintf(prompt, PLEASE_ENTER_PASSWORD, user);
+		msg[i].msg = prompt;
+	    }
+	} else {
+	    msg[i].msg = GUEST_LOGIN_PROMPT;
+	}
+
+	msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
+	mesg[i] = &msg[i];
+
+	retval = converse(pamh, ++i, mesg, &resp);
+	if (prompt) {
+	    _pam_overwrite(prompt);
+	    _pam_drop(prompt);
+	}
+
+	if (retval != PAM_SUCCESS) {
+	    if (resp != NULL)
+		_pam_drop_reply(resp,i);
+	    return ((retval == PAM_CONV_AGAIN)
+		    ? PAM_INCOMPLETE:PAM_AUTHINFO_UNAVAIL);
+	}
+
+	if (anon) {
+	    /* XXX: Some effort should be made to verify this email address! */
+
+	    if (!(ctrl & PAM_IGNORE_EMAIL)) {
+		token = strtok(resp->resp, "@");
+		retval = pam_set_item(pamh, PAM_RUSER, token);
+
+		if ((token) && (retval == PAM_SUCCESS)) {
+		    token = strtok(NULL, "@");
+		    retval = pam_set_item(pamh, PAM_RHOST, token);
+		}
+	    }
+
+	    /* we are happy to grant annonymous access to the user */
+	    retval = PAM_SUCCESS;
+
+	} else {
+	    /*
+	     * we have a password so set AUTHTOK
+	     */
+
+	    (void) pam_set_item(pamh, PAM_AUTHTOK, resp->resp);
+
+	    /*
+	     * this module failed, but the next one might succeed with
+	     * this password.
+	     */
+
+	    retval = PAM_AUTH_ERR;
+	}
+
+	if (resp) {                                      /* clean up */
+	    _pam_drop_reply(resp, i);
+	}
+
+	/* success or failure */
+
+	return retval;
+    }
+}
+
+PAM_EXTERN
+int pam_sm_setcred(pam_handle_t *pamh,int flags,int argc
+		   ,const char **argv)
+{
+     return PAM_IGNORE;
+}
+
+
+#ifdef PAM_STATIC
+
+/* static module data */
+
+struct pam_module _pam_ftp_modstruct = {
+     "pam_ftp",
+     pam_sm_authenticate,
+     pam_sm_setcred,
+     NULL,
+     NULL,
+     NULL,
+     NULL,
+};
+
+#endif
+
+/* end of module definition */
-- 
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