feature: enable one-way encrypted secrets

fixes #9

README.md

@@ -499,6 +499,8 @@ PRIVATE_KEY a path to a private SSH key used to decrypt file
 
 EDITOR environment variable of editor to use when editing FILE
 
+If STDIN is not interactive, EDITOR will be set to "cp /dev/stdin"
+
 RULES environment variable with path to Nix file specifying recipient public keys.
 Defaults to './secrets.nix'
 ```

pkgs/agenix.sh

@@ -114,7 +114,7 @@ function edit {
     CLEARTEXT_DIR=$(@mktempBin@ -d)
     CLEARTEXT_FILE="$CLEARTEXT_DIR/$(basename "$FILE")"
 
-    if [ -f "$FILE" ]
+    if [ -f "$FILE" ] && [ -t 0 ]
     then
         DECRYPT=("${DEFAULT_DECRYPT[@]}")
         if [[ "${DECRYPT[*]}" != *"--identity"* ]]; then
@@ -142,7 +142,7 @@ function edit {
       warn "$FILE wasn't created."
       return
     fi
-    [ -f "$FILE" ] && [ "$EDITOR" != ":" ] && @diffBin@ -q "$CLEARTEXT_FILE.before" "$CLEARTEXT_FILE" && warn "$FILE wasn't changed, skipping re-encryption." && return
+    [ -f "$FILE" ] && [ "$EDITOR" != ":" ]  && [ -f "$CLEARTEXT_FILE.before" ] && @diffBin@ -q "$CLEARTEXT_FILE.before" "$CLEARTEXT_FILE" && warn "$FILE wasn't changed, skipping re-encryption." && return
 
     ENCRYPT=()
     while IFS= read -r key

test/fixtures/one-way/secrets.nix

@@ -0,0 +1,5 @@
+let
+  system1 = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPJDyIr/FSz1cJdcoW69R+NrWzwGK/+3gJpqD1t8L2zE";
+in {
+  "one-way.age".publicKeys = [system1];
+}

test/install_ssh_host_keys.nix

@@ -24,5 +24,9 @@
     cp -r "${../example}" /tmp/secrets
     chmod -R u+rw /tmp/secrets
     chown -R $USER1_UID:$USERS_GID /tmp/secrets
+
+    cp -r "${./fixtures/one-way}" /tmp/secrets-one-way
+    chmod -R u+rw /tmp/secrets-one-way
+    chown -R $USER1_UID:$USERS_GID /tmp/secrets-one-way
   '';
 }

test/integration.nix

@@ -66,7 +66,8 @@ pkgs.nixosTest {
     system1.wait_for_file("/tmp/1")
     assert "${user}" in system1.succeed("cat /tmp/1")
 
-    userDo = lambda input : f"sudo -u user1 -- bash -c 'set -eou pipefail; cd /tmp/secrets; {input}'"
+    userDir = "/tmp/secrets"
+    userDo = lambda input : f"sudo -u user1 -- bash -c 'set -eou pipefail; cd {userDir}; {input}'"
 
     before_hash = system1.succeed(userDo('sha256sum passwordfile-user1.age')).split()
     print(system1.succeed(userDo('agenix -r -i /home/user1/.ssh/id_ed25519')))
@@ -89,7 +90,15 @@ pkgs.nixosTest {
     system1.succeed(userDo("rm ~/.ssh/id_rsa"))
 
     # user1 can edit a secret by piping in contents
-    system1.succeed(userDo("echo 'secret1234' | agenix -e passwordfile-user1.age"))
+    system1.succeed(userDo("echo secret1234 | agenix -e passwordfile-user1.age"))
     assert "secret1234" in system1.succeed(userDo("EDITOR=cat agenix -e passwordfile-user1.age"))
+
+    # user1 can make a one-way secret, but cannot see the contents, and host can decrypt
+    userDir = "/tmp/secrets-one-way"
+    system1.succeed(userDo("echo eye1234 | agenix -e one-way.age"))
+    system1.fail(userDo("EDITOR=cat agenix -e one-way.age"))
+    assert "eye1234" in system1.succeed(f"cd {userDir};EDITOR=cat agenix -e one-way.age -i /etc/ssh/ssh_host_ed25519_key")
+    system1.succeed(userDo("echo nose1234 | agenix -e one-way.age"))
+    assert "nose1234" in system1.succeed(f"cd {userDir};EDITOR=cat agenix -e one-way.age -i /etc/ssh/ssh_host_ed25519_key")
   '';
 }