cli: make the command line more user friendly.

Also has to fix up tests.

Changelog-Fixed: cli doesn't required anymore to confirm the password if the `hsm_secret` is already encrypted.

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

common/errcode.h

@@ -14,5 +14,6 @@ typedef s32 errcode_t;
 #define HSM_ERROR_IS_ENCRYPT 21
 #define HSM_BAD_PASSWORD 22
 #define HSM_PASSWORD_INPUT_ERR 23
+#define ERROR_HSM_FILE 24
 
 #endif /* LIGHTNING_COMMON_ERRCODE_H */

common/hsm_encryption.c

@@ -1,6 +1,8 @@
 #include "config.h"
+#include <ccan/tal/str/str.h>
 #include <common/errcode.h>
 #include <common/hsm_encryption.h>
+#include <errno.h>
 #include <termios.h>
 #include <unistd.h>
 
@@ -79,6 +81,17 @@ bool decrypt_hsm_secret(const struct secret *encryption_key,
 	return true;
 }
 
+/* Returns -1 on error (and sets errno), 0 if not encrypted, 1 if it is */
+int is_hsm_secret_encrypted(const char *path)
+{
+	struct stat st;
+
+        if (stat(path, &st) != 0)
+		return -1;
+
+        return st.st_size == ENCRYPTED_HSM_SECRET_LEN;
+}
+
 void discard_key(struct secret *key TAKES)
 {
 	/* sodium_munlock() also zeroes the memory. */

common/hsm_encryption.h

@@ -4,6 +4,7 @@
 #include <bitcoin/privkey.h>
 #include <ccan/tal/tal.h>
 #include <sodium.h>
+#include <sys/stat.h>
 
 /* Length of the encrypted hsm secret header. */
 #define HS_HEADER_LEN crypto_secretstream_xchacha20poly1305_HEADERBYTES
@@ -63,4 +64,6 @@ void discard_key(struct secret *key TAKES);
  */
 char *read_stdin_pass_with_exit_code(char **reason, int *exit_code);
 
+/** Returns -1 on error (and sets errno), 0 if not encrypted, 1 if it is */
+int is_hsm_secret_encrypted(const char *path);
 #endif /* LIGHTNING_COMMON_HSM_ENCRYPTION_H */

lightningd/hsm_control.c

@@ -96,11 +96,9 @@ struct ext_key *hsm_init(struct lightningd *ld)
 	 * not passed, don't let hsmd use the first 32 bytes of the cypher as the
 	 * actual secret. */
 	if (!ld->config.keypass) {
-		struct stat st;
-		if (stat("hsm_secret", &st) == 0 &&
-			 st.st_size == ENCRYPTED_HSM_SECRET_LEN)
+		if (is_hsm_secret_encrypted("hsm_secret") == 1)
 			errx(HSM_ERROR_IS_ENCRYPT, "hsm_secret is encrypted, you need to pass the "
-			        "--encrypted-hsm startup option.");
+			     "--encrypted-hsm startup option.");
 	}
 
 	ld->hsm_fd = fds[0];

lightningd/options.c

@@ -502,6 +502,12 @@ static char *opt_important_plugin(const char *arg, struct lightningd *ld)
 static char *opt_set_hsm_password(struct lightningd *ld)
 {
 	char *passwd, *passwd_confirmation, *err_msg;
+	int is_encrypted;
+
+        is_encrypted = is_hsm_secret_encrypted("hsm_secret");
+	if (is_encrypted == -1)
+		return tal_fmt(NULL, "Could not access 'hsm_secret': %s",
+			       strerror(errno));
 
 	printf("The hsm_secret is encrypted with a password. In order to "
 	       "decrypt it and start the node you must provide the password.\n");
@@ -513,17 +519,19 @@ static char *opt_set_hsm_password(struct lightningd *ld)
 	passwd = read_stdin_pass_with_exit_code(&err_msg, &opt_exitcode);
 	if (!passwd)
 		return err_msg;
-	printf("Confirm hsm_secret password:\n");
-	fflush(stdout);
-	passwd_confirmation = read_stdin_pass_with_exit_code(&err_msg, &opt_exitcode);
-	if (!passwd_confirmation)
-		return err_msg;
+	if (!is_encrypted) {
+		printf("Confirm hsm_secret password:\n");
+		fflush(stdout);
+		passwd_confirmation = read_stdin_pass_with_exit_code(&err_msg, &opt_exitcode);
+		if (!passwd_confirmation)
+			return err_msg;
 
-	if (!streq(passwd, passwd_confirmation)) {
-		opt_exitcode = HSM_BAD_PASSWORD;
-		return "Passwords confirmation mismatch.";
+		if (!streq(passwd, passwd_confirmation)) {
+			opt_exitcode = HSM_BAD_PASSWORD;
+			return "Passwords confirmation mismatch.";
+		}
+		free(passwd_confirmation);
 	}
-
 	printf("\n");
 
 	ld->config.keypass = tal(NULL, struct secret);
@@ -534,7 +542,6 @@ static char *opt_set_hsm_password(struct lightningd *ld)
 
 	ld->encrypted_hsm = true;
 	free(passwd);
-	free(passwd_confirmation);
 
 	return NULL;
 }

tests/test_wallet.py

@@ -1039,8 +1039,6 @@ def test_hsm_secret_encryption(node_factory):
                     wait_for_initialized=False)
     l1.daemon.wait_for_log(r'Enter hsm_secret password')
     write_all(master_fd, password[2:].encode("utf-8"))
-    l1.daemon.wait_for_log(r'Confirm hsm_secret password')
-    write_all(master_fd, password[2:].encode("utf-8"))
     assert(l1.daemon.proc.wait(WAIT_TIMEOUT) == HSM_BAD_PASSWORD)
     assert(l1.daemon.is_in_log("Wrong password for encrypted hsm_secret."))
 
@@ -1048,8 +1046,6 @@ def test_hsm_secret_encryption(node_factory):
     l1.daemon.start(stdin=slave_fd, wait_for_initialized=False)
     l1.daemon.wait_for_log(r'The hsm_secret is encrypted')
     write_all(master_fd, password.encode("utf-8"))
-    l1.daemon.wait_for_log(r'Confirm hsm_secret password')
-    write_all(master_fd, password.encode("utf-8"))
     l1.daemon.wait_for_log("Server started with public key")
     assert id == l1.rpc.getinfo()["id"]
     l1.stop()
@@ -1057,7 +1053,6 @@ def test_hsm_secret_encryption(node_factory):
     # We can restore the same wallet with the same password provided through stdin
     l1.daemon.start(stdin=subprocess.PIPE, wait_for_initialized=False)
     l1.daemon.proc.stdin.write(password.encode("utf-8"))
-    l1.daemon.proc.stdin.write(password.encode("utf-8"))
     l1.daemon.proc.stdin.flush()
     l1.daemon.wait_for_log("Server started with public key")
     assert id == l1.rpc.getinfo()["id"]
@@ -1138,8 +1133,6 @@ def test_hsmtool_secret_decryption(node_factory):
 
     l1.daemon.wait_for_log(r'The hsm_secret is encrypted')
     write_all(master_fd, password.encode("utf-8"))
-    l1.daemon.wait_for_log(r'Confirm hsm_secret password')
-    write_all(master_fd, password.encode("utf-8"))
     l1.daemon.wait_for_log("Server started with public key")
     print(node_id, l1.rpc.getinfo()["id"])
     assert node_id == l1.rpc.getinfo()["id"]

tools/hsmtool.c

@@ -10,18 +10,17 @@
 #include <common/configdir.h>
 #include <common/derive_basepoints.h>
 #include <common/descriptor_checksum.h>
+#include <common/errcode.h>
 #include <common/hsm_encryption.h>
 #include <common/node_id.h>
 #include <common/type_to_string.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
-#include <sys/stat.h>
 #include <unistd.h>
 #include <wally_bip32.h>
 #include <wally_bip39.h>
 
-#define ERROR_HSM_FILE errno
 #define ERROR_USAGE 2
 #define ERROR_LIBSODIUM 3
 #define ERROR_LIBWALLY 4
@@ -147,16 +146,24 @@ static void get_channel_seed(struct secret *channel_seed, struct node_id *peer_i
 /* We detect an encrypted hsm_secret as a hsm_secret which is 73-bytes long. */
 static bool hsm_secret_is_encrypted(const char *hsm_secret_path)
 {
-	struct stat st;
+        switch (is_hsm_secret_encrypted(hsm_secret_path)) {
+		case -1:
+			err(ERROR_HSM_FILE, "Cannot open '%s'", hsm_secret_path);
+		case 1:
+			return true;
+	        case 0: {
+			/* Extra sanity check on HSM file! */
+			struct stat st;
+			stat(hsm_secret_path, &st);
+			if (st.st_size != 32)
+				errx(ERROR_HSM_FILE,
+				     "Invalid hsm_secret '%s' (neither plaintext "
+				     "nor encrypted).", hsm_secret_path);
+			return false;
+		}
+	}
 
-	if (stat(hsm_secret_path, &st) != 0)
-		errx(ERROR_HSM_FILE, "Could not stat hsm_secret");
-
-	if (st.st_size != 32 && st.st_size != ENCRYPTED_HSM_SECRET_LEN)
-		errx(ERROR_HSM_FILE, "Invalid hsm_secret (neither plaintext "
-				     "nor encrypted).");
-
-	return st.st_size == ENCRYPTED_HSM_SECRET_LEN;
+	abort();
 }
 
 static int decrypt_hsm(const char *hsm_secret_path)