base-files: move urandom seed bits into separate package

So it's possible to install or remove it as needed.

Tested-by: Lucian Cristian <lucian.cristian@gmail.com>
Signed-off-by: Petr Štetiar <ynezz@true.cz>

3 files changed, 56 insertions, 0 deletions

diff --git a/package/system/urandom-seed/files/etc/init.d/urandom_seed b/package/system/urandom-seed/files/etc/init.d/urandom_seed
new file mode 100755
index 0000000000..17d9c13400
--- /dev/null
+++ b/package/system/urandom-seed/files/etc/init.d/urandom_seed
@@ -0,0 +1,12 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+USE_PROCD=1
+
+start_service() {
+    procd_open_instance "urandom_seed"
+    procd_set_param command "/sbin/urandom_seed"
+    procd_set_param stdout 1
+    procd_set_param stderr 1
+    procd_close_instance
+}
diff --git a/package/system/urandom-seed/files/lib/preinit/81_urandom_seed b/package/system/urandom-seed/files/lib/preinit/81_urandom_seed
new file mode 100644
index 0000000000..26212c60b5
--- /dev/null
+++ b/package/system/urandom-seed/files/lib/preinit/81_urandom_seed
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+log_urandom_seed() {
+    echo "urandom-seed: $1" > /dev/kmsg
+}
+
+_do_urandom_seed() {
+    [ -f "$1" ] || { log_urandom_seed "Seed file not found ($1)"; return; }
+    [ -O "$1" -a -G "$1" -a ! -x "$1" ] || { log_urandom_seed "Wrong owner / permissions for $1"; return; }
+
+    log_urandom_seed "Seeding with $1"
+    cat "$1" > /dev/urandom
+}
+
+do_urandom_seed() {
+    [ -c /dev/urandom ] || { log_urandom_seed "Something is wrong with /dev/urandom"; return; }
+
+    _do_urandom_seed "/etc/urandom.seed"
+
+    SEED="$(uci -q get system.@system[0].urandom_seed)"
+    [ "${SEED:0:1}" = "/" -a "$SEED" != "/etc/urandom.seed" ] && _do_urandom_seed "$SEED"
+}
+
+boot_hook_add preinit_main do_urandom_seed
diff --git a/package/system/urandom-seed/files/sbin/urandom_seed b/package/system/urandom-seed/files/sbin/urandom_seed
new file mode 100755
index 0000000000..7043e8af4e
--- /dev/null
+++ b/package/system/urandom-seed/files/sbin/urandom_seed
@@ -0,0 +1,20 @@
+#!/bin/sh
+set -e
+
+trap '[ "$?" -eq 0 ] || echo "An error occured" >&2' EXIT
+
+save() {
+    touch "$1.tmp"
+    chown root:root "$1.tmp"
+    chmod 600 "$1.tmp"
+    getrandom 512 > "$1.tmp"
+    mv "$1.tmp" "$1"
+    echo "Seed saved ($1)"
+}
+
+SEED="$(uci -q get system.@system[0].urandom_seed || true)"
+[ "${SEED:0:1}" = "/" ] && save "$SEED"
+
+SEED=/etc/urandom.seed
+[ ! -f $SEED ] && save "$SEED"
+true