From b0fc16bfc71156cbf5e423502428a6c058c1f89b Mon Sep 17 00:00:00 2001
From: Johannes Bauer <joe@johannes-bauer.com>
Date: Sun, 27 Jun 2021 09:47:59 +0200
Subject: [PATCH] Consistent naming and implemented flag honoring

Name the flag exactly as it's used by LUKS everywhere: allow_discards
(we had in some places "discard", "allow_discard"). Implement actually
honoring that flag if it's set. Untested code.
---
 client.c |  3 ++-
 editor.c | 10 +++++-----
 keydb.h  |  2 +-
 luks.c   | 28 +++++++++++++++++++++-------
 luks.h   |  2 +-
 5 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/client.c b/client.c
index ddfac7d..360bbf7 100644
--- a/client.c
+++ b/client.c
@@ -65,7 +65,8 @@ static bool unlock_luks_volume(const volume_entry_t *volume, const struct msg_t
 	bool success = true;
 	char luks_passphrase[LUKS_PASSPHRASE_TEXT_SIZE_BYTES];
 	if (ascii_encode(luks_passphrase, sizeof(luks_passphrase), unlock_msg->luks_passphrase_raw, sizeof(unlock_msg->luks_passphrase_raw))) {
-		success = open_luks_device(volume->volume_uuid, volume->devmapper_name, luks_passphrase, strlen(luks_passphrase));
+		bool allow_discards = volume->volume_flags & VOLUME_FLAG_ALLOW_DISCARDS;
+		success = open_luks_device(volume->volume_uuid, volume->devmapper_name, luks_passphrase, strlen(luks_passphrase), allow_discards);
 	} else {
 		log_msg(LLVL_FATAL, "Failed to transcribe raw LUKS passphrase to text form.");
 		success = false;
diff --git a/editor.c b/editor.c
index b5c19bf..5e7d91f 100644
--- a/editor.c
+++ b/editor.c
@@ -249,8 +249,8 @@ static enum cmd_returncode_t cmd_list(struct editor_context_t *ctx, const char *
 			if (volume->volume_flags == 0) {
 				printf("defaults");
 			} else {
-				if (volume->volume_flags & VOLUME_FLAG_ALLOW_DISCARD) {
-					printf("allow_discard ");
+				if (volume->volume_flags & VOLUME_FLAG_ALLOW_DISCARDS) {
+					printf("allow_discards ");
 				}
 			}
 			printf("\n");
@@ -409,10 +409,10 @@ static enum cmd_returncode_t cmd_flag_volume(struct editor_context_t *ctx, const
 	}
 
 	unsigned int flag_value = 0;
-	if (!strcasecmp(flag_str + 1, "discard")) {
-		flag_value = VOLUME_FLAG_ALLOW_DISCARD;
+	if (!strcasecmp(flag_str + 1, "allow_discards")) {
+		flag_value = VOLUME_FLAG_ALLOW_DISCARDS;
 	} else {
-		fprintf(stderr, "Invalid flag '%s': allowed is only 'discard'.\n", flag_str + 1);
+		fprintf(stderr, "Invalid flag '%s': allowed is only 'allow_discards'.\n", flag_str + 1);
 		return COMMAND_FAILURE;
 	}
 
diff --git a/keydb.h b/keydb.h
index 34cf004..3e79e6a 100644
--- a/keydb.h
+++ b/keydb.h
@@ -33,7 +33,7 @@
 #define ALIGNED		__attribute__ ((aligned(4)))
 
 enum volume_flag_t {
-	VOLUME_FLAG_ALLOW_DISCARD = (1 << 0),
+	VOLUME_FLAG_ALLOW_DISCARDS = (1 << 0),
 };
 
 /* Unused so far */
diff --git a/luks.c b/luks.c
index 164c506..c73809c 100644
--- a/luks.c
+++ b/luks.c
@@ -50,25 +50,39 @@ bool is_luks_device_opened(const char *mapping_name) {
 	return runresult.success && (runresult.returncode == 0);
 }
 
-bool open_luks_device(const uint8_t *encrypted_device_uuid, const char *mapping_name, const char *passphrase, unsigned int passphrase_length) {
+bool open_luks_device(const uint8_t *encrypted_device_uuid, const char *mapping_name, const char *passphrase, unsigned int passphrase_length, bool allow_discards) {
 	char encrypted_device[64];
 	strcpy(encrypted_device, "UUID=");
 	sprintf_uuid(encrypted_device + 5, encrypted_device_uuid);
 	log_msg(LLVL_INFO, "Trying to unlock LUKS mapping %s based on %s", mapping_name, encrypted_device);
 
 	struct exec_cmd_t cmd = {
-		.argv = (const char *[]){
+		.stdin_data = passphrase,
+		.stdin_length = passphrase_length,
+		.show_output = should_log(LLVL_DEBUG),
+	};
+
+	if (!allow_discards) {
+		cmd.argv = (const char *[]) {
 			"cryptsetup",
 			"luksOpen",
 			"-T", "1",
 			encrypted_device,
 			mapping_name,
 			NULL,
-		},
-		.stdin_data = passphrase,
-		.stdin_length = passphrase_length,
-		.show_output = should_log(LLVL_DEBUG),
-	};
+		};
+	} else {
+		cmd.argv = (const char *[]) {
+			"cryptsetup",
+			"--allow-discards",
+			"luksOpen",
+			"-T", "1",
+			encrypted_device,
+			mapping_name,
+			NULL,
+		};
+	}
+
 	struct exec_result_t runresult = exec_command(&cmd);
 	return runresult.success && (runresult.returncode == 0);
 }
diff --git a/luks.h b/luks.h
index 53521d9..0c5703a 100644
--- a/luks.h
+++ b/luks.h
@@ -29,7 +29,7 @@
 
 /*************** AUTO GENERATED SECTION FOLLOWS ***************/
 bool is_luks_device_opened(const char *mapping_name);
-bool open_luks_device(const uint8_t *encrypted_device_uuid, const char *mapping_name, const char *passphrase, unsigned int passphrase_length);
+bool open_luks_device(const uint8_t *encrypted_device_uuid, const char *mapping_name, const char *passphrase, unsigned int passphrase_length, bool allow_discards);
 /***************  AUTO GENERATED SECTION ENDS   ***************/
 
 #endif