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- pam_selinux: add env_params option which will be used by OpenSSH

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This commit is contained in:
Tomáš Mráz 2008-05-19 16:55:13 +00:00
parent be4deb2d92
commit afb096a17d
2 changed files with 567 additions and 1 deletions
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561
pam-1.0.0-selinux-env-params.patch Normal file
View File

@ -0,0 +1,561 @@
Index: modules/pam_selinux/pam_selinux.8.xml
===================================================================
RCS file: /cvsroot/pam/Linux-PAM/modules/pam_selinux/pam_selinux.8.xml,v
retrieving revision 1.2
diff -u -p -r1.2 pam_selinux.8.xml
--- modules/pam_selinux/pam_selinux.8.xml 15 Jun 2007 10:17:22 -0000 1.2
+++ modules/pam_selinux/pam_selinux.8.xml 19 May 2008 15:44:08 -0000
@@ -37,6 +37,9 @@
select_context
</arg>
<arg choice="opt">
+ env_params
+ </arg>
+ <arg choice="opt">
use_current_range
</arg>
</cmdsynopsis>
@@ -137,12 +140,30 @@
</varlistentry>
<varlistentry>
<term>
+ <option>env_params</option>
+ </term>
+ <listitem>
+ <para>
+ Attempt to obtain a custom security context role from PAM environment.
+ If MLS is on obtain also sensitivity level. This option and the
+ select_context option are mutually exclusive. The respective PAM
+ environment variables are <emphasis>SELINUX_ROLE_REQUESTED</emphasis>,
+ <emphasis>SELINUX_LEVEL_REQUESTED</emphasis>, and
+ <emphasis>SELINUX_USE_CURRENT_RANGE</emphasis>. The first two variables
+ are self describing and the last one if set to 1 makes the PAM module behave as
+ if the use_current_range was specified on the command line of the module.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>
<option>use_current_range</option>
</term>
<listitem>
<para>
- Use the sensitivity range of the process for the user context.
- This option and the select_context option are mutually exclusive.
+ Use the sensitivity level of the current process for the user context
+ instead of the default level. Also supresses asking of the
+ sensitivity level from the user or obtaining it from PAM environment.
</para>
</listitem>
</varlistentry>
Index: modules/pam_selinux/pam_selinux.c
===================================================================
RCS file: /cvsroot/pam/Linux-PAM/modules/pam_selinux/pam_selinux.c,v
retrieving revision 1.16
diff -u -p -r1.16 pam_selinux.c
--- modules/pam_selinux/pam_selinux.c 22 Apr 2008 19:21:37 -0000 1.16
+++ modules/pam_selinux/pam_selinux.c 19 May 2008 15:44:08 -0000
@@ -2,8 +2,9 @@
* A module for Linux-PAM that will set the default security context after login
* via PAM.
*
- * Copyright (c) 2003 Red Hat, Inc.
+ * Copyright (c) 2003-2008 Red Hat, Inc.
* Written by Dan Walsh <dwalsh@redhat.com>
+ * Additional improvements by Tomas Mraz <tmraz@redhat.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -138,15 +139,22 @@ send_text (pam_handle_t *pamh, const cha
*/
static int
query_response (pam_handle_t *pamh, const char *text, const char *def,
- char **responses, int debug)
+ char **response, int debug)
{
int rc;
if (def)
- rc = pam_prompt (pamh, PAM_PROMPT_ECHO_ON, responses, "%s [%s] ", text, def);
+ rc = pam_prompt (pamh, PAM_PROMPT_ECHO_ON, response, "%s [%s] ", text, def);
else
- rc = pam_prompt (pamh, PAM_PROMPT_ECHO_ON, responses, "%s ", text);
- if (debug)
- pam_syslog(pamh, LOG_NOTICE, "%s %s", text, responses[0]);
+ rc = pam_prompt (pamh, PAM_PROMPT_ECHO_ON, response, "%s ", text);
+
+ if (*response == NULL) {
+ rc = PAM_CONV_ERR;
+ }
+
+ if (rc != PAM_SUCCESS) {
+ pam_syslog(pamh, LOG_WARNING, "No response to query: %s", text);
+ } else if (debug)
+ pam_syslog(pamh, LOG_NOTICE, "%s %s", text, *response);
return rc;
}
@@ -157,13 +165,15 @@ manual_context (pam_handle_t *pamh, cons
context_t new_context;
int mls_enabled = is_selinux_mls_enabled();
char *type=NULL;
- char *responses=NULL;
+ char *response=NULL;
while (1) {
- query_response(pamh,
- _("Would you like to enter a security context? [N] "), NULL,
- &responses,debug);
- if ((responses[0] == 'y') || (responses[0] == 'Y'))
+ if (query_response(pamh,
+ _("Would you like to enter a security context? [N] "), NULL,
+ &response, debug) != PAM_SUCCESS)
+ return NULL;
+
+ if ((response[0] == 'y') || (response[0] == 'Y'))
{
if (mls_enabled)
new_context = context_new ("user:role:type:level");
@@ -176,26 +186,29 @@ manual_context (pam_handle_t *pamh, cons
if (context_user_set (new_context, user))
goto fail_set;
- _pam_drop(responses);
+ _pam_drop(response);
/* Allow the user to enter each field of the context individually */
- query_response(pamh,_("role:"), NULL, &responses,debug);
- if (responses[0] != '\0') {
- if (context_role_set (new_context, responses))
+ if (query_response(pamh, _("role:"), NULL, &response, debug) == PAM_SUCCESS &&
+ response[0] != '\0') {
+ if (context_role_set (new_context, response))
goto fail_set;
- if (get_default_type(responses, &type))
+ if (get_default_type(response, &type))
goto fail_set;
if (context_type_set (new_context, type))
goto fail_set;
}
- _pam_drop(responses);
+ _pam_drop(response);
+
if (mls_enabled)
{
- query_response(pamh,_("level:"), NULL, &responses,debug);
- if (responses[0] != '\0') {
- if (context_range_set (new_context, responses))
+ if (query_response(pamh, _("level:"), NULL, &response, debug) == PAM_SUCCESS &&
+ response[0] != '\0') {
+ if (context_range_set (new_context, response))
goto fail_set;
}
+ _pam_drop(response);
}
+
/* Get the string value of the context and see if it is valid. */
if (!security_check_context(context_str(new_context))) {
newcon = strdup(context_str(new_context));
@@ -204,16 +217,17 @@ manual_context (pam_handle_t *pamh, cons
}
else
send_text(pamh,_("Not a valid security context"),debug);
- context_free (new_context);
+
+ context_free (new_context);
}
else {
- _pam_drop(responses);
+ _pam_drop(response);
return NULL;
}
} /* end while */
fail_set:
free(type);
- _pam_drop(responses);
+ _pam_drop(response);
context_free (new_context);
return NULL;
}
@@ -239,69 +253,91 @@ static int mls_range_allowed(pam_handle_
}
static security_context_t
-config_context (pam_handle_t *pamh, security_context_t puser_context, int debug)
+config_context (pam_handle_t *pamh, security_context_t defaultcon, int use_current_range, int debug)
{
security_context_t newcon=NULL;
context_t new_context;
int mls_enabled = is_selinux_mls_enabled();
- char *responses=NULL;
+ char *response=NULL;
char *type=NULL;
char resp_val = 0;
- pam_prompt (pamh, PAM_TEXT_INFO, NULL, _("Default Security Context %s\n"), puser_context);
+ pam_prompt (pamh, PAM_TEXT_INFO, NULL, _("Default Security Context %s\n"), defaultcon);
while (1) {
- query_response(pamh,
+ if (query_response(pamh,
_("Would you like to enter a different role or level?"), "n",
- &responses,debug);
-
- resp_val = responses[0];
- _pam_drop(responses);
+ &response, debug) == PAM_SUCCESS) {
+ resp_val = response[0];
+ _pam_drop(response);
+ } else {
+ resp_val = 'N';
+ }
if ((resp_val == 'y') || (resp_val == 'Y'))
{
- new_context = context_new(puser_context);
-
+ if ((new_context = context_new(defaultcon)) == NULL)
+ goto fail_set;
+
/* Allow the user to enter role and level individually */
- query_response(pamh,_("role:"), context_role_get(new_context),
- &responses, debug);
- if (responses[0]) {
- if (get_default_type(responses, &type)) {
- pam_prompt (pamh, PAM_ERROR_MSG, NULL, _("No default type for role %s\n"), responses);
- _pam_drop(responses);
+ if (query_response(pamh, _("role:"), context_role_get(new_context),
+ &response, debug) == PAM_SUCCESS && response[0]) {
+ if (get_default_type(response, &type)) {
+ pam_prompt (pamh, PAM_ERROR_MSG, NULL, _("No default type for role %s\n"), response);
+ _pam_drop(response);
continue;
} else {
- if (context_role_set(new_context, responses))
+ if (context_role_set(new_context, response))
goto fail_set;
if (context_type_set (new_context, type))
goto fail_set;
}
}
- _pam_drop(responses);
+ _pam_drop(response);
+
if (mls_enabled)
{
- query_response(pamh,_("level:"), context_range_get(new_context),
- &responses, debug);
- if (responses[0]) {
- if (context_range_set(new_context, responses))
- goto fail_set;
+ if (use_current_range) {
+ security_context_t mycon = NULL;
+ context_t my_context;
+
+ if (getcon(&mycon) != 0)
+ goto fail_set;
+ my_context = context_new(mycon);
+ if (my_context == NULL) {
+ freecon(mycon);
+ goto fail_set;
+ }
+ freecon(mycon);
+ if (context_range_set(new_context, context_range_get(my_context))) {
+ context_free(my_context);
+ goto fail_set;
+ }
+ context_free(my_context);
+ } else if (query_response(pamh, _("level:"), context_range_get(new_context),
+ &response, debug) == PAM_SUCCESS && response[0]) {
+ if (context_range_set(new_context, response))
+ goto fail_set;
}
- _pam_drop(responses);
+ _pam_drop(response);
}
+
if (debug)
pam_syslog(pamh, LOG_NOTICE, "Selected Security Context %s", context_str(new_context));
/* Get the string value of the context and see if it is valid. */
if (!security_check_context(context_str(new_context))) {
newcon = strdup(context_str(new_context));
- context_free (new_context);
+ if (newcon == NULL)
+ goto fail_set;
+ context_free(new_context);
/* we have to check that this user is allowed to go into the
range they have specified ... role is tied to an seuser, so that'll
be checked at setexeccon time */
- if (mls_enabled && !mls_range_allowed(pamh, puser_context, newcon, debug)) {
- pam_syslog(pamh, LOG_NOTICE, "Security context %s is not allowed for %s", puser_context, newcon);
+ if (mls_enabled && !mls_range_allowed(pamh, defaultcon, newcon, debug)) {
+ pam_syslog(pamh, LOG_NOTICE, "Security context %s is not allowed for %s", defaultcon, newcon);
- send_audit_message(pamh, 0, puser_context, newcon);
+ send_audit_message(pamh, 0, defaultcon, newcon);
free(newcon);
goto fail_range;
@@ -309,26 +345,120 @@ config_context (pam_handle_t *pamh, secu
return newcon;
}
else {
- send_audit_message(pamh, 0, puser_context, context_str(new_context));
+ send_audit_message(pamh, 0, defaultcon, context_str(new_context));
send_text(pamh,_("Not a valid security context"),debug);
}
context_free(new_context); /* next time around allocates another */
}
else
- return strdup(puser_context);
+ return strdup(defaultcon);
} /* end while */
return NULL;
fail_set:
free(type);
- _pam_drop(responses);
+ _pam_drop(response);
context_free (new_context);
- send_audit_message(pamh, 0, puser_context, NULL);
+ send_audit_message(pamh, 0, defaultcon, NULL);
fail_range:
return NULL;
}
+static security_context_t
+context_from_env (pam_handle_t *pamh, security_context_t defaultcon, int env_params, int use_current_range, int debug)
+{
+ security_context_t newcon = NULL;
+ context_t new_context;
+ context_t my_context = NULL;
+ int mls_enabled = is_selinux_mls_enabled();
+ const char *env = NULL;
+ char *type = NULL;
+
+ if ((new_context = context_new(defaultcon)) == NULL)
+ goto fail_set;
+
+ if (env_params && (env = pam_getenv(pamh, "SELINUX_ROLE_REQUESTED")) != NULL && env[0] != '\0') {
+ if (debug)
+ pam_syslog(pamh, LOG_NOTICE, "Requested role: %s", env);
+
+ if (get_default_type(env, &type)) {
+ pam_syslog(pamh, LOG_NOTICE, "No default type for role %s", env);
+ goto fail_set;
+ } else {
+ if (context_role_set(new_context, env))
+ goto fail_set;
+ if (context_type_set(new_context, type))
+ goto fail_set;
+ }
+ }
+
+ if (mls_enabled) {
+ if ((env = pam_getenv(pamh, "SELINUX_USE_CURRENT_RANGE")) != NULL && env[0] == '1') {
+ if (debug)
+ pam_syslog(pamh, LOG_NOTICE, "SELINUX_USE_CURRENT_RANGE is set");
+ use_current_range = 1;
+ }
+
+ if (use_current_range) {
+ security_context_t mycon = NULL;
+
+ if (getcon(&mycon) != 0)
+ goto fail_set;
+ my_context = context_new(mycon);
+ if (my_context == NULL) {
+ freecon(mycon);
+ goto fail_set;
+ }
+ freecon(mycon);
+ env = context_range_get(my_context);
+ } else {
+ env = pam_getenv(pamh, "SELINUX_LEVEL_REQUESTED");
+ }
+
+ if (env != NULL && env[0] != '\0') {
+ if (debug)
+ pam_syslog(pamh, LOG_NOTICE, "Requested level: %s", env);
+ if (context_range_set(new_context, env))
+ goto fail_set;
+ }
+ }
+
+ newcon = strdup(context_str(new_context));
+ if (newcon == NULL)
+ goto fail_set;
+
+ if (debug)
+ pam_syslog(pamh, LOG_NOTICE, "Selected Security Context %s", newcon);
+
+ /* Get the string value of the context and see if it is valid. */
+ if (security_check_context(newcon)) {
+ pam_syslog(pamh, LOG_NOTICE, "Not a valid security context %s", newcon);
+ send_audit_message(pamh, 0, defaultcon, newcon);
+ freecon(newcon);
+ newcon = NULL;
+
+ goto fail_set;
+ }
+
+ /* we have to check that this user is allowed to go into the
+ range they have specified ... role is tied to an seuser, so that'll
+ be checked at setexeccon time */
+ if (mls_enabled && !mls_range_allowed(pamh, defaultcon, newcon, debug)) {
+ pam_syslog(pamh, LOG_NOTICE, "Security context %s is not allowed for %s", defaultcon, newcon);
+ send_audit_message(pamh, 0, defaultcon, newcon);
+ freecon(newcon);
+ newcon = NULL;
+ }
+
+ fail_set:
+ free(type);
+ context_free(my_context);
+ context_free(new_context);
+ send_audit_message(pamh, 0, defaultcon, NULL);
+ return newcon;
+}
+
static void
security_restorelabel_tty(const pam_handle_t *pamh,
const char *tty, security_context_t context)
@@ -439,13 +569,14 @@ PAM_EXTERN int
pam_sm_open_session(pam_handle_t *pamh, int flags UNUSED,
int argc, const char **argv)
{
- int i, debug = 0, ttys=1, has_tty=isatty(0);
+ int i, debug = 0, ttys=1;
int verbose=0, close_session=0;
int select_context = 0;
int use_current_range = 0;
int ret = 0;
security_context_t* contextlist = NULL;
int num_contexts = 0;
+ int env_params = 0;
const char *username = NULL;
const void *tty = NULL;
char *seuser=NULL;
@@ -472,13 +603,16 @@ pam_sm_open_session(pam_handle_t *pamh,
if (strcmp(argv[i], "use_current_range") == 0) {
use_current_range = 1;
}
+ if (strcmp(argv[i], "env_params") == 0) {
+ env_params = 1;
+ }
}
if (debug)
pam_syslog(pamh, LOG_NOTICE, "Open Session");
- if (select_context && use_current_range) {
- pam_syslog(pamh, LOG_ERR, "select_context cannot be used with use_current_range");
+ if (select_context && env_params) {
+ pam_syslog(pamh, LOG_ERR, "select_context cannot be used with env_params");
select_context = 0;
}
@@ -510,12 +644,17 @@ pam_sm_open_session(pam_handle_t *pamh,
freeconary(contextlist);
if (default_user_context == NULL) {
pam_syslog(pamh, LOG_ERR, "Out of memory");
- return PAM_AUTH_ERR;
+ return PAM_BUF_ERR;
}
+
user_context = default_user_context;
- if (select_context && has_tty) {
- user_context = config_context(pamh, default_user_context, debug);
- if (user_context == NULL) {
+ if (select_context) {
+ user_context = config_context(pamh, default_user_context, use_current_range, debug);
+ } else if (env_params || use_current_range) {
+ user_context = context_from_env(pamh, default_user_context, env_params, use_current_range, debug);
+ }
+
+ if (user_context == NULL) {
freecon(default_user_context);
pam_syslog(pamh, LOG_ERR, "Unable to get valid context for %s",
username);
@@ -524,11 +663,9 @@ pam_sm_open_session(pam_handle_t *pamh,
return PAM_AUTH_ERR;
else
return PAM_SUCCESS;
- }
- }
+ }
}
else {
- if (has_tty) {
user_context = manual_context(pamh,seuser,debug);
if (user_context == NULL) {
pam_syslog (pamh, LOG_ERR, "Unable to get valid context for %s",
@@ -538,59 +675,6 @@ pam_sm_open_session(pam_handle_t *pamh,
else
return PAM_SUCCESS;
}
- } else {
- pam_syslog (pamh, LOG_ERR,
- "Unable to get valid context for %s, No valid tty",
- username);
- if (security_getenforce() == 1)
- return PAM_AUTH_ERR;
- else
- return PAM_SUCCESS;
- }
- }
-
- if (use_current_range && is_selinux_mls_enabled()) {
- security_context_t process_context=NULL;
- if (getcon(&process_context) == 0) {
- context_t pcon, ucon;
- char *process_level=NULL;
- security_context_t orig_context;
-
- if (user_context)
- orig_context = user_context;
- else
- orig_context = default_user_context;
-
- pcon = context_new(process_context);
- freecon(process_context);
- process_level = strdup(context_range_get(pcon));
- context_free(pcon);
-
- if (debug)
- pam_syslog (pamh, LOG_DEBUG, "process level=%s", process_level);
-
- ucon = context_new(orig_context);
-
- context_range_set(ucon, process_level);
- free(process_level);
-
- if (!mls_range_allowed(pamh, orig_context, context_str(ucon), debug)) {
- send_text(pamh, _("Requested MLS level not in permitted range"), debug);
- /* even if default_user_context is NULL audit that anyway */
- send_audit_message(pamh, 0, default_user_context, context_str(ucon));
- context_free(ucon);
- return PAM_AUTH_ERR;
- }
-
- if (debug)
- pam_syslog (pamh, LOG_DEBUG, "adjusted context=%s", context_str(ucon));
-
- /* replace the user context with the level adjusted one */
- freecon(user_context);
- user_context = strdup(context_str(ucon));
-
- context_free(ucon);
- }
}
if (getexeccon(&prev_user_context)<0) {
@@ -613,7 +697,7 @@ pam_sm_open_session(pam_handle_t *pamh,
}
}
}
- if(ttys && tty ) {
+ if (ttys && tty) {
ttyn=strdup(tty);
ttyn_context=security_label_tty(pamh,ttyn,user_context);
}

7
pam.spec
View File

@ -5,7 +5,7 @@
Summary: A security tool which provides authentication for applications
Name: pam
Version: 1.0.1
Release: 2%{?dist}
Release: 3%{?dist}
# The library is BSD licensed with option to relicense as GPLv2+ - this option is redundant
# as the BSD license allows that anyway. pam_timestamp and pam_console modules are GPLv2+,
# pam_rhosts_auth module is BSD with advertising
@ -27,6 +27,7 @@ Patch2: db-4.6.18-glibc.patch
Patch4: pam-0.99.8.1-dbpam.patch
Patch10: pam-1.0.0-sepermit-screensaver.patch
Patch11: pam-1.0.1-selinux-restore-execcon.patch
Patch12: pam-1.0.0-selinux-env-params.patch
Patch21: pam-0.99.10.0-unix-audit-failed.patch
Patch31: pam-0.99.3.0-cracklib-try-first-pass.patch
Patch32: pam-0.99.3.0-tally-fail-close.patch
@ -104,6 +105,7 @@ popd
%patch4 -p1 -b .dbpam
%patch10 -p1 -b .screensaver
%patch11 -p1 -b .restore-execcon
%patch12 -p0 -b .env-params
%patch21 -p1 -b .audit-failed
%patch31 -p1 -b .try-first-pass
%patch32 -p1 -b .fail-close
@ -376,6 +378,9 @@ fi
%doc doc/adg/*.txt doc/adg/html
%changelog
* Mon May 19 2008 Tomas Mraz <tmraz@redhat.com> 1.0.1-3
- pam_selinux: add env_params option which will be used by OpenSSH
* Tue Apr 22 2008 Tomas Mraz <tmraz@redhat.com> 1.0.1-2
- pam_selinux: restore execcon properly (#443667)