From: Yann E. MORIN <yann.morin.1998@free.fr>
Date: Tue, 25 Aug 2015 21:43:33 +0000 (+0200)
Subject: package/dropbear: add warning about volatile keys
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8012250b86dc5c7fa9a882c82ae5364a6ede3512;p=buildroot.git

package/dropbear: add warning about volatile keys

When the rootfs is read-only, keys will be generated in a volatile
location, which is inherently bad as host keys will change on each boot,
rendering them virtually useless.

Add a warning so the user is at least aware of the issue.

Hide the rm output to avoid noisy output, now that we have a proper warning.

Move the starting message after the symlink-block, to avoid messages
collision. Move the umask as well, since /etc/dropbear/ may be world
readable; just the private host keys should be ?00 (and dropbear handles
that by itself).

[Peter: minor tweaks to commit message]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Peter Korsgaard <jacmet@uclibc.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---

diff --git a/package/dropbear/S50dropbear b/package/dropbear/S50dropbear
index 765d6a3e1d..b4e3c5c685 100644
--- a/package/dropbear/S50dropbear
+++ b/package/dropbear/S50dropbear
@@ -9,9 +9,6 @@ test -r /etc/default/dropbear && . /etc/default/dropbear
 start() {
 	DROPBEAR_ARGS="$DROPBEAR_ARGS -R"
 
-	echo -n "Starting dropbear sshd: "
-	umask 077
-
 	# If /etc/dropbear is a symlink to /var/run/dropbear, and
 	#   - the filesystem is RO (i.e. we can not rm the symlink),
 	#     create the directory pointed to by the symlink.
@@ -20,13 +17,18 @@ start() {
 	if [ -L /etc/dropbear \
 	     -a "$(readlink /etc/dropbear)" = "/var/run/dropbear" ]
 	then
-		if rm -f /etc/dropbear; then
+		if rm -f /etc/dropbear >/dev/null 2>&1; then
 			mkdir -p /etc/dropbear
 		else
-			mkdir -p $(readlink /etc/dropbear)
+			echo "No persistent location to store SSH host keys. New keys will be"
+			echo "generated at each boot. Are you sure this is what you want to do?"
+			mkdir -p "$(readlink /etc/dropbear)"
 		fi
 	fi
 
+	echo -n "Starting dropbear sshd: "
+	umask 077
+
 	start-stop-daemon -S -q -p /var/run/dropbear.pid \
 		--exec /usr/sbin/dropbear -- $DROPBEAR_ARGS
 	[ $? = 0 ] && echo "OK" || echo "FAIL"
diff --git a/package/dropbear/dropbear.service b/package/dropbear/dropbear.service
index 9dcbf256cd..1eb42f9d09 100644
--- a/package/dropbear/dropbear.service
+++ b/package/dropbear/dropbear.service
@@ -11,10 +11,12 @@ After=syslog.target network.target auditd.service
 ExecStartPre=/bin/sh -c '\
 if [ -L /etc/dropbear \
      -a "$(readlink /etc/dropbear)" = "/var/run/dropbear" ]; then \
-    if rm -f /etc/dropbear; then \
+    if rm -f /etc/dropbear >/dev/null 2>&1; then \
         mkdir -p /etc/dropbear; \
     else \
-        mkdir -p $(readlink /etc/dropbear); \
+        echo "No persistent location to store SSH host keys. New keys will be"; \
+        echo "generated at each boot. Are you sure this is what you want to do?"; \
+        mkdir -p "$(readlink /etc/dropbear)"; \
     fi; \
 fi'
 ExecStart=/usr/sbin/dropbear -F -R