Add a Securelevel sub-menu to the Security configuration menu,

permitting the administrator to select a securelevel top operate
at.  Include a helpfile summarizing some of the information from
init(8).  This allows for explicit configuration of securelevels,
which was previously implicit in Security Profile selection.
Currently, there are no checkboxes for the active securelevel,
because sysinstall's facilities for deriving "current settings"
from rc.conf may use only one variable, not two, and I opted for
the simplest approach at this point.

Approved by:	re (scottl)

7 files changed, 190 insertions, 0 deletions

diff --git a/usr.sbin/sade/config.c b/usr.sbin/sade/config.c
index 570cb61..27937e1 100644
--- a/usr.sbin/sade/config.c
+++ b/usr.sbin/sade/config.c
@@ -537,6 +537,52 @@ configOSF1(dialogMenuItem *self)
 #endif
 
 int
+configSecurelevel(dialogMenuItem *self)
+{
+    WINDOW *w = savescr();
+
+    dialog_clear_norefresh();
+    dmenuOpenSimple(&MenuSecurelevel, FALSE);
+    restorescr(w);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelDisabled(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "NO", 1);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelSecure(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "YES", 1);
+    variable_set2("kern_securelevel", "1", 1);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelHighlySecure(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "YES", 1);
+    variable_set2("kern_securelevel", "2", 1);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelNetworkSecure(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "YES", 1);
+    variable_set2("kern_securelevel", "3", 1);
+    return DITEM_SUCCESS;
+}
+
+int
 configSecurity(dialogMenuItem *self)
 {
     WINDOW *w = savescr();
diff --git a/usr.sbin/sade/menus.c b/usr.sbin/sade/menus.c
index ef4608c..46b7270 100644
--- a/usr.sbin/sade/menus.c
+++ b/usr.sbin/sade/menus.c
@@ -2229,6 +2229,8 @@ DMenu MenuSecurity = {
     NULL,
     { { "X Exit",      "Exit this menu (returning to previous)",
 	checkTrue, dmenuExit, NULL, NULL, '<', '<', '<' },
+      { " Securelevel",	"Configure securelevels for the system",
+	NULL, configSecurelevel },
 #if 0
       { " LOMAC",         "Use Low Watermark Mandatory Access Control at boot",
 	dmenuVarCheck,  dmenuToggleVariable, NULL, "lomac_enable=YES" },
@@ -2238,6 +2240,28 @@ DMenu MenuSecurity = {
       { NULL } },
 };
 
+DMenu MenuSecurelevel = {
+    DMENU_NORMAL_TYPE | DMENU_SELECTION_RETURNS,
+    "Securelevel Configuration Menu",
+    "This menu allows you to select the securelevel your system runs with.\n"
+    "When operating at a securelevel, certain root privileges are disabled,\n"
+    "which may increase resistance to exploits and protect system integrity.\n"
+    "In secure mode system flags may not be overriden by the root user,\n"
+    "access to direct kernel memory is limited, and kernel modules may not\n"
+    "be changed.  In highly secure mode, mounted file systems may not be\n"
+    "modified on-disk, tampering with the system clock is prohibited.  In\n"
+    "network secure mode configuration changes to firwalling are prohibited.\n",
+    "Select a securelevel to operate at - F1 for help",
+    "securelevel",
+    { { "X Exit",      "Exit this menu (returning to previous)",
+	checkTrue, dmenuExit, NULL, NULL, '<', '<', '<' },
+      { "Disabled", "Disable securelevels", NULL, configSecurelevelDisabled, },
+      { "Secure", "Secure mode", NULL, configSecurelevelSecure },
+      { "Highly Secure", "Highly secure mode", NULL, configSecurelevelHighlySecure }, 
+      { "Network Secure", "Network secure mode", NULL, configSecurelevelNetworkSecure },
+      { NULL } }
+};
+
 DMenu MenuFixit = {
     DMENU_NORMAL_TYPE,
     "Please choose a fixit option",
diff --git a/usr.sbin/sade/sade.h b/usr.sbin/sade/sade.h
index 9ba8336..507bfca 100644
--- a/usr.sbin/sade/sade.h
+++ b/usr.sbin/sade/sade.h
@@ -143,6 +143,7 @@
 #define VAR_IPADDR			"ipaddr"
 #define VAR_IPV6_ENABLE			"ipv6_enable"
 #define VAR_IPV6ADDR			"ipv6addr"
+#define VAR_KERN_SECURELEVEL		"kern_securelevel"
 #define VAR_KEYMAP			"keymap"
 #define VAR_LABEL			"label"
 #define VAR_LABEL_COUNT			"labelCount"
@@ -452,6 +453,7 @@ extern DMenu		MenuMediaTape;		/* Tape media menu				*/
 extern DMenu		MenuNetworkDevice;	/* Network device menu				*/
 extern DMenu		MenuNTP;		/* NTP time server menu				*/
 extern DMenu		MenuSecurity;		/* System security options menu			*/
+extern DMenu		MenuSecurelevel;	/* Securelevel menu */
 extern DMenu		MenuStartup;		/* Startup services menu			*/
 #ifdef WITH_SYSCONS
 extern DMenu		MenuSyscons;		/* System console configuration menu		*/
@@ -531,6 +533,11 @@ extern int	configMTAPostfix(dialogMenuItem *self);
 extern int	configMTAExim(dialogMenuItem *self);
 extern int	configRpcBind(dialogMenuItem *self);
 extern int	configWriteRC_conf(dialogMenuItem *self);
+extern int	configSecurelevel(dialogMenuItem *self);
+extern int	configSecurelevelDisabled(dialogMenuItem *self);
+extern int	configSecurelevelSecure(dialogMenuItem *self);
+extern int	configSecurelevelHighlySecure(dialogMenuItem *self);
+extern int	configSecurelevelNetworkSecure(dialogMenuItem *self);
 extern int	configEtcTtys(dialogMenuItem *self);
 #ifdef __i386__
 extern int	checkLoaderACPI(void);
diff --git a/usr.sbin/sysinstall/config.c b/usr.sbin/sysinstall/config.c
index 570cb61..27937e1 100644
--- a/usr.sbin/sysinstall/config.c
+++ b/usr.sbin/sysinstall/config.c
@@ -537,6 +537,52 @@ configOSF1(dialogMenuItem *self)
 #endif
 
 int
+configSecurelevel(dialogMenuItem *self)
+{
+    WINDOW *w = savescr();
+
+    dialog_clear_norefresh();
+    dmenuOpenSimple(&MenuSecurelevel, FALSE);
+    restorescr(w);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelDisabled(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "NO", 1);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelSecure(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "YES", 1);
+    variable_set2("kern_securelevel", "1", 1);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelHighlySecure(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "YES", 1);
+    variable_set2("kern_securelevel", "2", 1);
+    return DITEM_SUCCESS;
+}
+
+int
+configSecurelevelNetworkSecure(dialogMenuItem *self)
+{
+
+    variable_set2("kern_securelevel_enable", "YES", 1);
+    variable_set2("kern_securelevel", "3", 1);
+    return DITEM_SUCCESS;
+}
+
+int
 configSecurity(dialogMenuItem *self)
 {
     WINDOW *w = savescr();
diff --git a/usr.sbin/sysinstall/help/securelevel.hlp b/usr.sbin/sysinstall/help/securelevel.hlp
new file mode 100644
index 0000000..44fa39b
--- /dev/null
+++ b/usr.sbin/sysinstall/help/securelevel.hlp
@@ -0,0 +1,36 @@
+This menu allows you to configure the Securelevel mechanism in FreeBSD.
+
+Securelevels may be used to limit the privileges assigned to the
+root user in multi-user mode, which in turn may limit the effects of
+a root compromise, at the cost of reducing administrative functions.
+Refer to the init(8) manual page for complete details.
+
+   -1    Permanently insecure mode - always run the system in level 0 mode.
+         This is the default initial value.
+
+   0     Insecure mode - immutable and append-only flags may be turned off.
+         All devices may be read or written subject to their permissions.
+
+   1     Secure mode - the system immutable and system append-only flags may
+         not be turned off; disks for mounted file systems, /dev/mem, and
+         /dev/kmem may not be opened for writing; kernel modules (see
+         kld(4)) may not be loaded or unloaded.
+
+   2     Highly secure mode - same as secure mode, plus disks may not be
+         opened for writing (except by mount(2)) whether mounted or not.
+         This level precludes tampering with file systems by unmounting
+         them, but also inhibits running newfs(8) while the system is multi-
+         user.
+
+         In addition, kernel time changes are restricted to less than or
+         equal to one second.  Attempts to change the time by more than this
+         will log the message ``Time adjustment clamped to +1 second''.
+
+   3     Network secure mode - same as highly secure mode, plus IP packet
+         filter rules (see ipfw(8) and ipfirewall(4)) cannot be changed and
+         dummynet(4) configuration cannot be adjusted.
+
+Securelevels must be used in combination with careful system design and
+application of protective mechanisms to prevent system configuration
+files from being modified in a way that compromises the protections of
+the securelevel variable upon reboot.
diff --git a/usr.sbin/sysinstall/menus.c b/usr.sbin/sysinstall/menus.c
index ef4608c..46b7270 100644
--- a/usr.sbin/sysinstall/menus.c
+++ b/usr.sbin/sysinstall/menus.c
@@ -2229,6 +2229,8 @@ DMenu MenuSecurity = {
     NULL,
     { { "X Exit",      "Exit this menu (returning to previous)",
 	checkTrue, dmenuExit, NULL, NULL, '<', '<', '<' },
+      { " Securelevel",	"Configure securelevels for the system",
+	NULL, configSecurelevel },
 #if 0
       { " LOMAC",         "Use Low Watermark Mandatory Access Control at boot",
 	dmenuVarCheck,  dmenuToggleVariable, NULL, "lomac_enable=YES" },
@@ -2238,6 +2240,28 @@ DMenu MenuSecurity = {
       { NULL } },
 };
 
+DMenu MenuSecurelevel = {
+    DMENU_NORMAL_TYPE | DMENU_SELECTION_RETURNS,
+    "Securelevel Configuration Menu",
+    "This menu allows you to select the securelevel your system runs with.\n"
+    "When operating at a securelevel, certain root privileges are disabled,\n"
+    "which may increase resistance to exploits and protect system integrity.\n"
+    "In secure mode system flags may not be overriden by the root user,\n"
+    "access to direct kernel memory is limited, and kernel modules may not\n"
+    "be changed.  In highly secure mode, mounted file systems may not be\n"
+    "modified on-disk, tampering with the system clock is prohibited.  In\n"
+    "network secure mode configuration changes to firwalling are prohibited.\n",
+    "Select a securelevel to operate at - F1 for help",
+    "securelevel",
+    { { "X Exit",      "Exit this menu (returning to previous)",
+	checkTrue, dmenuExit, NULL, NULL, '<', '<', '<' },
+      { "Disabled", "Disable securelevels", NULL, configSecurelevelDisabled, },
+      { "Secure", "Secure mode", NULL, configSecurelevelSecure },
+      { "Highly Secure", "Highly secure mode", NULL, configSecurelevelHighlySecure }, 
+      { "Network Secure", "Network secure mode", NULL, configSecurelevelNetworkSecure },
+      { NULL } }
+};
+
 DMenu MenuFixit = {
     DMENU_NORMAL_TYPE,
     "Please choose a fixit option",
diff --git a/usr.sbin/sysinstall/sysinstall.h b/usr.sbin/sysinstall/sysinstall.h
index 9ba8336..507bfca 100644
--- a/usr.sbin/sysinstall/sysinstall.h
+++ b/usr.sbin/sysinstall/sysinstall.h
@@ -143,6 +143,7 @@
 #define VAR_IPADDR			"ipaddr"
 #define VAR_IPV6_ENABLE			"ipv6_enable"
 #define VAR_IPV6ADDR			"ipv6addr"
+#define VAR_KERN_SECURELEVEL		"kern_securelevel"
 #define VAR_KEYMAP			"keymap"
 #define VAR_LABEL			"label"
 #define VAR_LABEL_COUNT			"labelCount"
@@ -452,6 +453,7 @@ extern DMenu		MenuMediaTape;		/* Tape media menu				*/
 extern DMenu		MenuNetworkDevice;	/* Network device menu				*/
 extern DMenu		MenuNTP;		/* NTP time server menu				*/
 extern DMenu		MenuSecurity;		/* System security options menu			*/
+extern DMenu		MenuSecurelevel;	/* Securelevel menu */
 extern DMenu		MenuStartup;		/* Startup services menu			*/
 #ifdef WITH_SYSCONS
 extern DMenu		MenuSyscons;		/* System console configuration menu		*/
@@ -531,6 +533,11 @@ extern int	configMTAPostfix(dialogMenuItem *self);
 extern int	configMTAExim(dialogMenuItem *self);
 extern int	configRpcBind(dialogMenuItem *self);
 extern int	configWriteRC_conf(dialogMenuItem *self);
+extern int	configSecurelevel(dialogMenuItem *self);
+extern int	configSecurelevelDisabled(dialogMenuItem *self);
+extern int	configSecurelevelSecure(dialogMenuItem *self);
+extern int	configSecurelevelHighlySecure(dialogMenuItem *self);
+extern int	configSecurelevelNetworkSecure(dialogMenuItem *self);
 extern int	configEtcTtys(dialogMenuItem *self);
 #ifdef __i386__
 extern int	checkLoaderACPI(void);