Please review openssh patch for selinux

[Daniel J Walsh <dwalsh@redhat.com>]

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New SSH patch.

Provides the capability of doing

ssh hostname -l root/sysadm_r

suggested by Collin. 

I used the / instead of : to preserve the BSD syntax.

Comments?


Dan


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--- openssh-3.9p1/monitor_wrap.h.selinux	2004-06-21 22:56:02.000000000 -0400
+++ openssh-3.9p1/monitor_wrap.h	2004-09-02 16:01:12.361473922 -0400
@@ -44,6 +44,7 @@
 DH *mm_choose_dh(int, int, int);
 int mm_key_sign(Key *, u_char **, u_int *, u_char *, u_int);
 void mm_inform_authserv(char *, char *);
+void mm_inform_authrole(char *);
 struct passwd *mm_getpwnamallow(const char *);
 char *mm_auth2_read_banner(void);
 int mm_auth_password(struct Authctxt *, char *);
--- openssh-3.9p1/contrib/redhat/sshd.init.selinux	2002-05-09 22:19:23.000000000 -0400
+++ openssh-3.9p1/contrib/redhat/sshd.init	2004-09-02 16:01:12.363473687 -0400
@@ -35,6 +35,9 @@
 		if $KEYGEN -q -t rsa1 -f $RSA1_KEY -C '' -N '' >&/dev/null; then
 			chmod 600 $RSA1_KEY
 			chmod 644 $RSA1_KEY.pub
+			if [ -x /sbin/restorecon ]; then
+			    /sbin/restorecon $RSA1_KEY.pub
+			fi
 			success $"RSA1 key generation"
 			echo
 		else
@@ -51,6 +54,9 @@
 		if $KEYGEN -q -t rsa -f $RSA_KEY -C '' -N '' >&/dev/null; then
 			chmod 600 $RSA_KEY
 			chmod 644 $RSA_KEY.pub
+			if [ -x /sbin/restorecon ]; then
+			    /sbin/restorecon $RSA_KEY.pub
+			fi
 			success $"RSA key generation"
 			echo
 		else
@@ -67,6 +73,9 @@
 		if $KEYGEN -q -t dsa -f $DSA_KEY -C '' -N '' >&/dev/null; then
 			chmod 600 $DSA_KEY
 			chmod 644 $DSA_KEY.pub
+			if [ -x /sbin/restorecon ]; then
+			    /sbin/restorecon $DSA_KEY.pub
+			fi
 			success $"DSA key generation"
 			echo
 		else
--- openssh-3.9p1/auth1.c.selinux	2004-09-02 16:01:12.290482263 -0400
+++ openssh-3.9p1/auth1.c	2004-09-02 16:02:18.505704965 -0400
@@ -283,7 +283,7 @@
 do_authentication(Authctxt *authctxt)
 {
 	u_int ulen;
-	char *user, *style = NULL;
+	char *user, *style = NULL, *role=NULL;
 
 	/* Get the name of the user that we wish to log in as. */
 	packet_read_expect(SSH_CMSG_USER);
@@ -292,11 +292,15 @@
 	user = packet_get_string(&ulen);
 	packet_check_eom();
 
+	if ((role = strchr(user, '/')) != NULL)
+		*role++ = '\0';
+
 	if ((style = strchr(user, ':')) != NULL)
 		*style++ = '\0';
 
 	authctxt->user = user;
 	authctxt->style = style;
+	authctxt->role = role;
 
 	/* Verify that the user is a valid user. */
 	if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL)
--- openssh-3.9p1/monitor.h.selinux	2003-11-17 06:18:22.000000000 -0500
+++ openssh-3.9p1/monitor.h	2004-09-02 16:01:12.366473335 -0400
@@ -30,7 +30,7 @@
 
 enum monitor_reqtype {
 	MONITOR_REQ_MODULI, MONITOR_ANS_MODULI,
-	MONITOR_REQ_FREE, MONITOR_REQ_AUTHSERV,
+	MONITOR_REQ_FREE, MONITOR_REQ_AUTHSERV,MONITOR_REQ_AUTHROLE,
 	MONITOR_REQ_SIGN, MONITOR_ANS_SIGN,
 	MONITOR_REQ_PWNAM, MONITOR_ANS_PWNAM,
 	MONITOR_REQ_AUTH2_READ_BANNER, MONITOR_ANS_AUTH2_READ_BANNER,
--- openssh-3.9p1/monitor.c.selinux	2004-07-17 03:05:14.000000000 -0400
+++ openssh-3.9p1/monitor.c	2004-09-02 16:01:12.369472982 -0400
@@ -111,6 +111,7 @@
 int mm_answer_pwnamallow(int, Buffer *);
 int mm_answer_auth2_read_banner(int, Buffer *);
 int mm_answer_authserv(int, Buffer *);
+int mm_answer_authrole(int, Buffer *);
 int mm_answer_authpassword(int, Buffer *);
 int mm_answer_bsdauthquery(int, Buffer *);
 int mm_answer_bsdauthrespond(int, Buffer *);
@@ -176,6 +177,7 @@
     {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign},
     {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow},
     {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv},
+    {MONITOR_REQ_AUTHROLE, MON_ONCE, mm_answer_authrole},
     {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner},
     {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
 #ifdef USE_PAM
@@ -602,6 +604,7 @@
 	else {
 		/* Allow service/style information on the auth context */
 		monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1);
+		monitor_permit(mon_dispatch, MONITOR_REQ_AUTHROLE, 1);
 		monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1);
 	}
 
@@ -647,6 +650,23 @@
 }
 
 int
+mm_answer_authrole(int sock, Buffer *m)
+{
+	monitor_permit_authentications(1);
+
+	authctxt->role = buffer_get_string(m, NULL);
+	debug3("%s: style=%s",
+	    __func__, authctxt->role);
+
+	if (strlen(authctxt->role) == 0) {
+		xfree(authctxt->role);
+		authctxt->role = NULL;
+	}
+
+	return (0);
+}
+
+int
 mm_answer_authpassword(int sock, Buffer *m)
 {
 	static int call_count;
--- openssh-3.9p1/config.h.in.selinux	2004-08-17 08:54:51.000000000 -0400
+++ openssh-3.9p1/config.h.in	2004-09-02 16:01:12.371472747 -0400
@@ -265,6 +265,9 @@
 /* Define if you want Kerberos 5 support */
 #undef KRB5
 
+/* Define if have want SELinux support */
+#undef WITH_SELINUX
+
 /* Define this if you are using the Heimdal version of Kerberos V5 */
 #undef HEIMDAL
 
--- /dev/null	2004-08-26 15:03:20.000000000 -0400
+++ openssh-3.9p1/selinux.c	2004-09-02 16:01:12.375472277 -0400
@@ -0,0 +1,101 @@
+#include "includes.h"
+#include "auth.h"
+#include "log.h"
+
+#ifdef WITH_SELINUX
+#include <selinux/selinux.h>
+#include <selinux/flask.h>
+#include <selinux/context.h>
+#include <selinux/get_context_list.h>
+#include <selinux/get_default_type.h>
+extern Authctxt *the_authctxt;
+
+static const security_context_t selinux_get_user_context(const char *name) {
+	security_context_t user_context=NULL;
+	if (get_default_context(name,NULL,&user_context)) {
+		if (security_getenforce() > 0) 
+			fatal("Failed to get default security context for %s.", name);
+		else 
+			error("Failed to get default security context for %s. Continuing in permissve mode", name);
+	} else {
+		if (the_authctxt) {
+			char *role=the_authctxt->role;
+			if (role != NULL && role[0]) {
+				char *type;
+				if (get_default_type(role, &type) < 0) {
+					if (security_getenforce() > 0) 
+						fatal("Failed to get default type for role %s, user %s.", role, name);
+					else 
+						error("Failed to get default type for role %s, user %s. Continuing in permissive mode", role, name);
+				} else {
+					context_t newcon=context_new(user_context);
+					if (context_role_set(newcon, role) != 0) {
+						context_free(newcon);
+						if (security_getenforce() > 0) 
+							fatal("Failed to set role %s for %s.", role, name);
+						else 
+							error("Failed to set role %s for %s. Continuing in permissive mode", role, name);
+					} else if (context_type_set(newcon, type) != 0) {
+						context_free(newcon);
+						if (security_getenforce() > 0) 
+							fatal("Failed to set type %s for %s.", role, name);
+						else 
+							error("Failed to set type %s for %s. Continuing in permissive mode", role, name);
+					} else {
+						freecon(user_context);
+						user_context = strdup(context_str(newcon));
+						context_free(newcon);
+					}
+				}
+			}
+		}
+	}
+	return user_context;
+}
+
+void setup_selinux_pty(const char *name, const char *tty) {
+	if (is_selinux_enabled() > 0) {
+		security_context_t new_tty_context=NULL, user_context=NULL, old_tty_context=NULL; 
+
+		user_context=selinux_get_user_context(name);
+
+		if (getfilecon(tty, &old_tty_context) < 0) {
+			error("getfilecon(%.100s) failed: %.100s", tty, strerror(errno));
+		} else {
+			if (security_compute_relabel(user_context,old_tty_context,
+						     SECCLASS_CHR_FILE,
+						     &new_tty_context) != 0) {
+				error("security_compute_relabel(%.100s) failed: %.100s", tty,
+				      strerror(errno));
+			} else {
+				if (setfilecon (tty, new_tty_context) != 0) 
+					error("setfilecon(%.100s, %s) failed: %.100s",
+					      tty, new_tty_context, 
+					      strerror(errno));
+				freecon(new_tty_context);
+			}
+			freecon(old_tty_context);
+		}
+		if (user_context) {
+			freecon(user_context);
+		}
+	}
+}
+
+void setup_selinux_exec_context(char *name) {
+
+	if (is_selinux_enabled() > 0) {
+		security_context_t user_context=selinux_get_user_context(name);
+		if (setexeccon(user_context)) {
+			if (security_getenforce() > 0) 
+				fatal("Failed to set exec security context %s for %s.", user_context, name);
+			else 
+				error("Failed to set exec security context %s for %s. Continuing in permissive mode", user_context, name);
+		}
+		if (user_context) {
+			freecon(user_context);
+		}
+	}
+}
+
+#endif /* WITH_SELINUX */
--- openssh-3.9p1/auth.h.selinux	2004-05-23 20:36:23.000000000 -0400
+++ openssh-3.9p1/auth.h	2004-09-02 16:01:12.377472042 -0400
@@ -57,6 +57,7 @@
 	char		*service;
 	struct passwd	*pw;		/* set if 'valid' */
 	char		*style;
+	char		*role;
 	void		*kbdintctxt;
 #ifdef BSD_AUTH
 	auth_session_t	*as;
--- openssh-3.9p1/sshpty.c.selinux	2004-06-21 22:56:02.000000000 -0400
+++ openssh-3.9p1/sshpty.c	2004-09-02 16:01:12.378471925 -0400
@@ -22,6 +22,8 @@
 #include "log.h"
 #include "misc.h"
 
+#include "selinux.h"
+
 #ifdef HAVE_PTY_H
 # include <pty.h>
 #endif
@@ -200,6 +202,8 @@
 		fatal("stat(%.100s) failed: %.100s", tty,
 		    strerror(errno));
 
+	setup_selinux_pty(pw->pw_name, tty);
+
 	if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
 		if (chown(tty, pw->pw_uid, gid) < 0) {
 			if (errno == EROFS &&
--- openssh-3.9p1/configure.ac.selinux	2004-09-02 16:01:12.327477916 -0400
+++ openssh-3.9p1/configure.ac	2004-09-02 16:01:12.382471455 -0400
@@ -2218,6 +2218,18 @@
 			[#include <arpa/nameser.h>])
 	])
 
+# Check whether user wants SELinux support
+SELINUX_MSG="no"
+AC_ARG_WITH(selinux,
+	[  --with-selinux   Enable SELinux support],
+	[ if test "x$withval" != "xno" ; then
+		AC_DEFINE(WITH_SELINUX)
+		SELINUX_MSG="yes"
+		AC_CHECK_HEADERS(selinux.h)
+		LIBS="$LIBS -lselinux"
+	fi
+	])
+
 # Check whether user wants Kerberos 5 support
 KRB5_MSG="no"
 AC_ARG_WITH(kerberos5,
@@ -2975,6 +2987,7 @@
 echo "                    Manpage format: $MANTYPE"
 echo "                       PAM support: $PAM_MSG"
 echo "                 KerberosV support: $KRB5_MSG"
+echo "                   SELinux support: $SELINUX_MSG"
 echo "                 Smartcard support: $SCARD_MSG"
 echo "                     S/KEY support: $SKEY_MSG"
 echo "              TCP Wrappers support: $TCPW_MSG"
--- openssh-3.9p1/Makefile.in.selinux	2004-08-15 07:01:37.000000000 -0400
+++ openssh-3.9p1/Makefile.in	2004-09-02 16:01:12.385471103 -0400
@@ -76,7 +76,7 @@
 	sshconnect.o sshconnect1.o sshconnect2.o
 
 SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o \
-	sshpty.o sshlogin.o servconf.o serverloop.o \
+	sshpty.o sshlogin.o servconf.o serverloop.o selinux.o \
 	auth.o auth1.o auth2.o auth-options.o session.o \
 	auth-chall.o auth2-chall.o groupaccess.o \
 	auth-skey.o auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
--- /dev/null	2004-08-26 15:03:20.000000000 -0400
+++ openssh-3.9p1/selinux.h	2004-09-02 16:01:12.386470985 -0400
@@ -0,0 +1,10 @@
+#ifndef __SELINUX_H_
+#define __SELINUX_H_
+#ifdef WITH_SELINUX
+extern void setup_selinux_pty(const char *name, const char *tty);
+extern void setup_selinux_exec_context(const char *name);
+#else
+inline void setup_selinux_pty(const char *name, const char *tty) {}
+inline void setup_selinux_exec_context(const char *name) {} 
+#endif /* WITH_SELINUX */
+#endif /* __SELINUX_H_ */
--- openssh-3.9p1/auth2.c.selinux	2004-08-12 08:40:25.000000000 -0400
+++ openssh-3.9p1/auth2.c	2004-09-02 16:01:12.389470633 -0400
@@ -132,7 +132,7 @@
 {
 	Authctxt *authctxt = ctxt;
 	Authmethod *m = NULL;
-	char *user, *service, *method, *style = NULL;
+	char *user, *service, *method, *style = NULL, *role = NULL;
 	int authenticated = 0;
 
 	if (authctxt == NULL)
@@ -144,6 +144,9 @@
 	debug("userauth-request for user %s service %s method %s", user, service, method);
 	debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
 
+	if ((role = strchr(user, '/')) != NULL)
+		*role++ = 0;
+
 	if ((style = strchr(user, ':')) != NULL)
 		*style++ = 0;
 
@@ -170,8 +173,11 @@
 		    use_privsep ? " [net]" : "");
 		authctxt->service = xstrdup(service);
 		authctxt->style = style ? xstrdup(style) : NULL;
-		if (use_privsep)
+		authctxt->role = role ? xstrdup(role) : NULL;
+		if (use_privsep) {
 			mm_inform_authserv(service, style);
+			mm_inform_authrole(role);
+		}
 	} else if (strcmp(user, authctxt->user) != 0 ||
 	    strcmp(service, authctxt->service) != 0) {
 		packet_disconnect("Change of username or service not allowed: "
--- openssh-3.9p1/monitor_wrap.c.selinux	2004-07-17 03:05:14.000000000 -0400
+++ openssh-3.9p1/monitor_wrap.c	2004-09-02 16:01:12.391470398 -0400
@@ -274,6 +274,23 @@
 	buffer_free(&m);
 }
 
+/* Inform the privileged process about role */
+
+void
+mm_inform_authrole(char *role)
+{
+	Buffer m;
+
+	debug3("%s entering", __func__);
+
+	buffer_init(&m);
+	buffer_put_cstring(&m, role ? role : "");
+
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHROLE, &m);
+
+	buffer_free(&m);
+}
+
 /* Do the password authentication */
 int
 mm_auth_password(Authctxt *authctxt, char *password)
--- openssh-3.9p1/session.c.selinux	2004-08-12 08:40:25.000000000 -0400
+++ openssh-3.9p1/session.c	2004-09-02 16:01:12.395469928 -0400
@@ -58,6 +58,8 @@
 #include "session.h"
 #include "monitor_wrap.h"
 
+#include "selinux.h"
+
 #if defined(KRB5) && defined(USE_AFS)
 #include <kafs.h>
 #endif
@@ -1304,6 +1306,8 @@
 #endif
 	if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
 		fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
+
+	setup_selinux_exec_context(pw->pw_name);
 }
 
 static void