Test that tor correctly handles zero-length keys

Check that tor generates new keys, and overwrites the empty key files.
Test that tor generates new keys when keys are missing (existing
behaviour).
Test that tor does not overwrite key files that already contain data
(existing behaviour).

Tests fixes to bug 13111.

changes/bug13111-generate-keys-on-empty-file

@@ -1,17 +1,23 @@
-  o Minor bugfixes
+  o Minor bugfixes (file handling):
     - Stop failing when key files are zero-length. Instead, generate new
       keys, and overwrite the empty key files.
-      Fixes bug 13111.
+      Fixes bug 13111. Patch by "teor".
     - Stop generating a fresh .old RSA key file when the .old file is missing.
-      Fixed as part of bug 13111.
     - Avoid overwriting .old key files with empty key files.
-      Fixed as part of bug 13111.
     - Stop crashing when a NULL filename is passed to file_status().
-      Fixed as part of bug 13111.
+      Fixed as part of bug 13111. Patches by "teor".
 
-  o Minor enhancements:
+  o Minor enhancements (file handling):
     - Skip loading zero-length extra info store, router store, stats, state,
       and key files.
-      Implemented with bug 13111.
     - Return FN_ERROR when a zero-length filename is passed to file_status().
-      Fixed as part of bug 13111.
+      Fixed as part of bug 13111. Patches by "teor".
+
+  o Minor enhancements (testing):
+    - Test that tor does not fail when key files are zero-length.
+      Check that tor generates new keys, and overwrites the empty key files.
+    - Test that tor generates new keys when keys are missing (existing
+      behaviour).
+    - Test that tor does not overwrite key files that already contain data
+      (existing behaviour).
+      Tests bug 13111. Patch by "teor".

src/test/include.am

@@ -120,9 +120,11 @@ if USEPYTHON
 	./src/test/test-bt-cl assert | $(PYTHON) $(top_srcdir)/src/test/bt_test.py
 	./src/test/test-bt-cl crash | $(PYTHON) $(top_srcdir)/src/test/bt_test.py
 endif
+	./src/test/zero_length_keys.sh
 
 EXTRA_DIST += \
 	src/test/bt_test.py \
 	src/test/ntor_ref.py \
 	src/test/slownacl_curve25519.py \
-	src/test/test_cmdline_args.py
+	src/test/test_cmdline_args.py \
+	src/test/zero_length_keys.sh

src/test/zero_length_keys.sh

@@ -0,0 +1,113 @@
+#!/bin/sh
+# Check that tor regenerates keys when key files are zero-length
+# Test for bug #13111 - Tor fails to start if onion keys are zero length
+#
+# Usage:
+#  ./zero_length_keys.sh
+#    Run all the tests below
+#  ./zero_length_keys.sh -z
+#    Check tor will launch and regenerate zero-length keys
+#  ./zero_length_keys.sh -d
+#    Check tor regenerates deleted keys (existing behaviour)
+#  ./zero_length_keys.sh -e
+#    Check tor does not overwrite existing keys (existing behaviour)
+#
+# Exit Statuses:
+#  -2: test failed - tor did not generate the key files on first run
+#  -1: a command failed - the test could not be completed
+#   0: test succeeded - tor regenerated/kept the files
+#   1: test failed - tor did not regenerate/keep the files
+#
+
+if [ $# -lt 1 ]; then
+  echo "Testing that tor correctly handles zero-length keys"
+  "$0" -z && "$0" -d && "$0" -e
+  exit $?
+fi
+
+export DATA_DIR=`mktemp -d -t tor_zero_length_keys`
+TOR="src/or/tor --hush --DisableNetwork 1 --ShutdownWaitLength 0 --ORPort 12345"
+
+if [ -s "$DATA_DIR"/keys/secret_id_key -a -s "$DATA_DIR"/keys/secret_onion_key -a -s "$DATA_DIR"/keys/secret_onion_key_ntor ]; then
+  echo "Failure: Previous tor keys present in tor data directory"
+  exit -1
+else
+  echo "Generating initial tor keys"
+  $TOR --DataDirectory "$DATA_DIR" --PidFile "$DATA_DIR"/pid &
+  TOR_PID=$!
+  # generate SIGTERM, hopefully after the keys have been regenerated
+  sleep 5
+  kill $TOR_PID
+  wait $TOR_PID
+
+  # tor must successfully generate non-zero-length key files
+  if [ -s "$DATA_DIR"/keys/secret_id_key -a -s "$DATA_DIR"/keys/secret_onion_key -a -s "$DATA_DIR"/keys/secret_onion_key_ntor ]; then
+    true #echo "tor generated the initial key files"
+  else
+    echo "Failure: tor failed to generate the initial key files"
+    exit -2
+  fi
+fi
+
+#ls -lh  "$DATA_DIR"/keys/ || exit -1
+
+# backup and keep/delete/create zero-length files for the keys
+
+FILE_DESC="keeps existing"
+# make a backup
+cp -r "$DATA_DIR"/keys "$DATA_DIR"/keys.old
+
+# delete keys for -d or -z
+if [ "$1" != "-e" ]; then
+  FILE_DESC="regenerates deleted"
+  rm "$DATA_DIR"/keys/secret_id_key || exit -1
+  rm "$DATA_DIR"/keys/secret_onion_key || exit -1
+  rm "$DATA_DIR"/keys/secret_onion_key_ntor || exit -1
+fi
+
+# create empty files for -z
+if [ "$1" == "-z" ]; then
+  FILE_DESC="regenerates zero-length"
+  touch "$DATA_DIR"/keys/secret_id_key || exit -1
+  touch "$DATA_DIR"/keys/secret_onion_key || exit -1
+  touch "$DATA_DIR"/keys/secret_onion_key_ntor || exit -1
+fi
+
+echo "Running tor again to check if it $FILE_DESC keys"
+$TOR --DataDirectory "$DATA_DIR" --PidFile "$DATA_DIR"/pid &
+TOR_PID=$!
+# generate SIGTERM, hopefully after the keys have been regenerated
+sleep 5
+kill $TOR_PID
+wait $TOR_PID
+
+#ls -lh "$DATA_DIR"/keys/ || exit -1
+
+# tor must always have non-zero-length key files
+if [ -s "$DATA_DIR"/keys/secret_id_key -a -s "$DATA_DIR"/keys/secret_onion_key -a -s "$DATA_DIR"/keys/secret_onion_key_ntor ]; then
+  # check if the keys are different to the old ones
+  diff -q -r "$DATA_DIR"/keys "$DATA_DIR"/keys.old > /dev/null
+  SAME_KEYS=$?
+  # if we're not testing existing keys,
+  # the current keys should be different to the old ones
+  if [ "$1" != "-e" ]; then
+    if [ $SAME_KEYS -ne 0 ]; then
+      echo "Success: test that tor $FILE_DESC key files: different keys"
+      exit 0
+    else
+      echo "Failure: test that tor $FILE_DESC key files: same keys"
+      exit 1
+    fi
+  else #[ "$1" == "-e" ]; then
+    if [ $SAME_KEYS -eq 0 ]; then
+      echo "Success: test that tor $FILE_DESC key files: same keys"
+      exit 0
+    else
+      echo "Failure: test that tor $FILE_DESC key files: different keys"
+      exit 1
+    fi
+  fi
+else
+  echo "Failure: test that tor $FILE_DESC key files: no key files"
+  exit 1
+fi