From: Ralf Jung <post@ralfj.de>
Date: Sat, 22 Feb 2014 11:42:21 +0000 (+0100)
Subject: add filesystem hardening (mounting external filesystems read-only, nosuid, and so on)
X-Git-Url: https://git.ralfj.de/schsh.git/commitdiff_plain/c8435c302e51661e0bcf1a1e27da67f0f2eddf32?ds=inline

add filesystem hardening (mounting external filesystems read-only, nosuid, and so on)
---

diff --git a/Makefile b/Makefile
index 531c14f..5ee18ce 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,8 @@ TARGET := /usr/local
 SCHROOT := /etc/schroot
 
 install:
-	install -o root -g root schsh makeschsh schsh-rrsync $(TARGET)/bin/
-	install -o root -g root -d $(SCHROOT)/schsh/
+	install -o root -g root -m 755 schsh makeschsh schsh-rrsync $(TARGET)/bin/
+	install -o root -g root -m 755 -d $(SCHROOT)/schsh/
 	install -o root -g root -m 644 schroot/schsh/* $(SCHROOT)/schsh/
-	install -o root -g root -d /var/lib/schsh/
+	install -o root -g root -m 755 schroot/setup.d/* $(SCHROOT)/setup.d/
+	install -o root -g root -m 755 -d /var/lib/schsh/
diff --git a/schroot/schsh/schsh-hardening b/schroot/schsh/schsh-hardening
new file mode 100644
index 0000000..077d4cd
--- /dev/null
+++ b/schroot/schsh/schsh-hardening
@@ -0,0 +1,12 @@
+# Describes how to re-mount some filesystems, if they happen to exist
+# Format: Mount-Point <TAB> remount-options
+/				bind,ro,nosuid,noexec
+/bin 			bind,ro,nosuid,nodev
+/lib	 		bind,ro,nosuid,nodev
+/lib64			bind,ro,nosuid,nodev
+/usr/bin 		bind,ro,nosuid,nodev
+/usr/lib		bind,ro,nosuid,nodev
+/usr/lib64		bind,ro,nosuid,nodev
+/usr/share		bind,ro,nosuid,nodev
+/usr/local/bin 	bind,ro,nosuid,nodev
+/data			bind,rw,nosuid,nodev,noexec
diff --git a/schroot/setup.d/80schsh-hardening b/schroot/setup.d/80schsh-hardening
new file mode 100755
index 0000000..47965e2
--- /dev/null
+++ b/schroot/setup.d/80schsh-hardening
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+. "$SETUP_DATA_DIR/common-data"
+. "$SETUP_DATA_DIR/common-functions"
+. "$SETUP_DATA_DIR/common-config"
+
+SETUP_HARDENING="$CHROOT_PROFILE_DIR/schsh-hardening"
+
+# Mount filesystems from fstab for all chroot types
+if [ "$STAGE" = "setup-start" ] || [ "$STAGE" = "setup-recover" ]; then
+	if [ "$CHROOT_PROFILE" = "schsh" ]; then
+		if [ -f "$SETUP_HARDENING" ]; then
+			while read REMOUNT; do
+				if echo "$REMOUNT" | egrep -q '^(#|$)' ; then
+					continue
+				fi
+				REMOUNT=$(echo "$REMOUNT" | tr ' ' '\t' | tr -s '\t') # replace spaces by tabs, and squeeze tabs together
+				MOUNTPOINT=${CHROOT_PATH}/$(echo "$REMOUNT" | cut -f 1)
+				MOUNTPOINT=$(readlink -m "$MOUNTPOINT") # canonicalize the path
+				MOUNTOPT=$(echo "$REMOUNT" | cut -f 2)
+				if cat /proc/mounts | grep " $MOUNTPOINT " > /dev/null; then # somehow "mountpoint" does not detect bind points...
+					info "Re-mounting $MOUNTPOINT with $MOUNTOPT"
+					mount -o remount,"$MOUNTOPT" "$MOUNTPOINT"
+				else
+					info "No such mountpoint: $MOUNTPOINT"
+				fi
+				
+			done < "$SETUP_HARDENING"
+		else
+			fatal "schsh-hardening file '$SETUP_HARDENING' does not exist"
+		fi
+	else
+		info "Not a schsh chroot, not doing anything"
+	fi
+fi