dm crypt: simplify crypt_ctr

Allocate cipher strings indpendently of struct crypt_config and move cipher parsing and allocation into a separate function to prepare for supporting the cryptoapi format e.g. "xts(aes)". No functional change in this patch. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>

dm crypt: simplify crypt_ctr
Allocate cipher strings indpendently of struct crypt_config and move cipher parsing and allocation into a separate function to prepare for supporting the cryptoapi format e.g. "xts(aes)". No functional change in this patch. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Milan Broz · Alasdair G Kergon
1 parent 28513fccf0
Showing 1 changed file with 104 additions and 81 deletions Side-by-side Diff
drivers/md/dm-crypt.c
@@ -107,11 +107,10 @@
 	struct workqueue_struct *io_queue;
 	struct workqueue_struct *crypt_queue;
  
-	/*
-	 * crypto related data
-	 */
+	char *cipher;
+	char *cipher_mode;
+
 	struct crypt_iv_operations *iv_gen_ops;
-	char *iv_mode;
 	union {
 		struct iv_essiv_private essiv;
 		struct iv_benbi_private benbi;
@@ -135,8 +134,6 @@
 	unsigned int dmreq_start;
 	struct ablkcipher_request *req;
  
-	char cipher[CRYPTO_MAX_ALG_NAME];
-	char chainmode[CRYPTO_MAX_ALG_NAME];
 	struct crypto_ablkcipher *tfm;
 	unsigned long flags;
 	unsigned int key_size;
  
  
  
  
  
  
  
  
  
  
  
  
  
@@ -1032,90 +1029,102 @@
 	if (cc->dev)
 		dm_put_device(ti, cc->dev);
  
-	kfree(cc->iv_mode);
+	kzfree(cc->cipher);
+	kzfree(cc->cipher_mode);
  
 	/* Must zero key material before freeing */
 	kzfree(cc);
 }
  
-/*
- * Construct an encryption mapping:
- * <cipher> <key> <iv_offset> <dev_path> <start>
- */
-static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+static int crypt_ctr_cipher(struct dm_target *ti,
+			    char *cipher_in, char *key)
 {
-	struct crypt_config *cc;
-	char *tmp;
-	char *cipher;
-	char *chainmode;
-	char *ivmode;
-	char *ivopts;
-	unsigned int key_size;
-	unsigned long long tmpll;
+	struct crypt_config *cc = ti->private;
+	char *tmp, *cipher, *chainmode, *ivmode, *ivopts;
+	char *cipher_api = NULL;
 	int ret = -EINVAL;
  
-	if (argc != 5) {
-		ti->error = "Not enough arguments";
+	/* Convert to crypto api definition? */
+	if (strchr(cipher_in, '(')) {
+		ti->error = "Bad cipher specification";
 		return -EINVAL;
 	}
  
-	tmp = argv[0];
+	/*
+	 * Legacy dm-crypt cipher specification
+	 * cipher-mode-iv:ivopts
+	 */
+	tmp = cipher_in;
 	cipher = strsep(&tmp, "-");
+
+	cc->cipher = kstrdup(cipher, GFP_KERNEL);
+	if (!cc->cipher)
+		goto bad_mem;
+
+	if (tmp) {
+		cc->cipher_mode = kstrdup(tmp, GFP_KERNEL);
+		if (!cc->cipher_mode)
+			goto bad_mem;
+	}
+
 	chainmode = strsep(&tmp, "-");
 	ivopts = strsep(&tmp, "-");
 	ivmode = strsep(&ivopts, ":");
  
 	if (tmp)
-		DMWARN("Unexpected additional cipher options");
+		DMWARN("Ignoring unexpected additional cipher options");
  
-	key_size = strlen(argv[1]) >> 1;
-
- 	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
-	if (!cc) {
-		ti->error = "Cannot allocate transparent encryption context";
-		return -ENOMEM;
-	}
-
-	ti->private = cc;
-
-	/* Compatibility mode for old dm-crypt cipher strings */
-	if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
+	/* Compatibility mode for old dm-crypt mappings */
+	if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
+		kfree(cc->cipher_mode);
+		cc->cipher_mode = kstrdup("cbc-plain", GFP_KERNEL);
 		chainmode = "cbc";
 		ivmode = "plain";
 	}
  
 	if (strcmp(chainmode, "ecb") && !ivmode) {
-		ti->error = "This chaining mode requires an IV mechanism";
-		goto bad;
+		ti->error = "IV mechanism required";
+		return -EINVAL;
 	}
  
-	ret = -ENOMEM;
-	if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
-		     chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
-		ti->error = "Chain mode + cipher name is too long";
-		goto bad;
+	cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
+	if (!cipher_api)
+		goto bad_mem;
+
+	ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
+		       "%s(%s)", chainmode, cipher);
+	if (ret < 0) {
+		kfree(cipher_api);
+		goto bad_mem;
 	}
  
-	cc->tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
+	/* Allocate cipher */
+	cc->tfm = crypto_alloc_ablkcipher(cipher_api, 0, 0);
 	if (IS_ERR(cc->tfm)) {
+		ret = PTR_ERR(cc->tfm);
 		ti->error = "Error allocating crypto tfm";
 		goto bad;
 	}
  
-	strcpy(cc->cipher, cipher);
-	strcpy(cc->chainmode, chainmode);
-
-	ret = crypt_set_key(cc, argv[1]);
+	/* Initialize and set key */
+	ret = crypt_set_key(cc, key);
 	if (ret < 0) {
 		ti->error = "Error decoding and setting key";
 		goto bad;
 	}
  
-	/*
-	 * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
-	 * See comments at iv code
-	 */
-	ret = -EINVAL;
+	/* Initialize IV */
+	cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
+	if (cc->iv_size)
+		/* at least a 64 bit sector number should fit in our buffer */
+		cc->iv_size = max(cc->iv_size,
+				  (unsigned int)(sizeof(u64) / sizeof(u8)));
+	else if (ivmode) {
+		DMWARN("Selected cipher does not support IVs");
+		ivmode = NULL;
+	}
+
+	/* Choose ivmode, see comments at iv code. */
 	if (ivmode == NULL)
 		cc->iv_gen_ops = NULL;
 	else if (strcmp(ivmode, "plain") == 0)
@@ -1129,6 +1138,7 @@
 	else if (strcmp(ivmode, "null") == 0)
 		cc->iv_gen_ops = &crypt_iv_null_ops;
 	else {
+		ret = -EINVAL;
 		ti->error = "Invalid IV mode";
 		goto bad;
 	}
  
@@ -1151,20 +1161,45 @@
 		}
 	}
  
-	cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
-	if (cc->iv_size)
-		/* at least a 64 bit sector number should fit in our buffer */
-		cc->iv_size = max(cc->iv_size,
-				  (unsigned int)(sizeof(u64) / sizeof(u8)));
-	else {
-		if (cc->iv_gen_ops) {
-			DMWARN("Selected cipher does not support IVs");
-			if (cc->iv_gen_ops->dtr)
-				cc->iv_gen_ops->dtr(cc);
-			cc->iv_gen_ops = NULL;
-		}
+	ret = 0;
+bad:
+	kfree(cipher_api);
+	return ret;
+
+bad_mem:
+	ti->error = "Cannot allocate cipher strings";
+	return -ENOMEM;
+}
+
+/*
+ * Construct an encryption mapping:
+ * <cipher> <key> <iv_offset> <dev_path> <start>
+ */
+static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct crypt_config *cc;
+	unsigned int key_size;
+	unsigned long long tmpll;
+	int ret;
+
+	if (argc != 5) {
+		ti->error = "Not enough arguments";
+		return -EINVAL;
 	}
  
+	key_size = strlen(argv[1]) >> 1;
+
+	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
+	if (!cc) {
+		ti->error = "Cannot allocate encryption context";
+		return -ENOMEM;
+	}
+
+	ti->private = cc;
+	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
+	if (ret < 0)
+		goto bad;
+
 	ret = -ENOMEM;
 	cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
 	if (!cc->io_pool) {
@@ -1217,17 +1252,6 @@
 	cc->start = tmpll;
  
 	ret = -ENOMEM;
-	if (ivmode && cc->iv_gen_ops) {
-		if (ivopts)
-			*(ivopts - 1) = ':';
-		cc->iv_mode = kstrdup(ivmode, GFP_KERNEL);
-		if (!cc->iv_mode) {
-			ti->error = "Error kmallocing iv_mode string";
-			goto bad;
-		}
-	} else
-		cc->iv_mode = NULL;
-
 	cc->io_queue = create_singlethread_workqueue("kcryptd_io");
 	if (!cc->io_queue) {
 		ti->error = "Couldn't create kcryptd io queue";
@@ -1273,7 +1297,7 @@
 static int crypt_status(struct dm_target *ti, status_type_t type,
 			char *result, unsigned int maxlen)
 {
-	struct crypt_config *cc = (struct crypt_config *) ti->private;
+	struct crypt_config *cc = ti->private;
 	unsigned int sz = 0;
  
 	switch (type) {
  
@@ -1282,11 +1306,10 @@
 		break;
  
 	case STATUSTYPE_TABLE:
-		if (cc->iv_mode)
-			DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
-			       cc->iv_mode);
+		if (cc->cipher_mode)
+			DMEMIT("%s-%s ", cc->cipher, cc->cipher_mode);
 		else
-			DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
+			DMEMIT("%s ", cc->cipher);
  
 		if (cc->key_size > 0) {
 			if ((maxlen - sz) < ((cc->key_size << 1) + 1))
...	...	@@ -107,11 +107,10 @@
107	107	struct workqueue_struct *io_queue;
108	108	struct workqueue_struct *crypt_queue;
109	109
110		- /*
111		- * crypto related data
112		- */
	110	+ char *cipher;
	111	+ char *cipher_mode;
	112	+
113	113	struct crypt_iv_operations *iv_gen_ops;
114		- char *iv_mode;
115	114	union {
116	115	struct iv_essiv_private essiv;
117	116	struct iv_benbi_private benbi;
...	...	@@ -135,8 +134,6 @@
135	134	unsigned int dmreq_start;
136	135	struct ablkcipher_request *req;
137	136
138		- char cipher[CRYPTO_MAX_ALG_NAME];
139		- char chainmode[CRYPTO_MAX_ALG_NAME];
140	137	struct crypto_ablkcipher *tfm;
141	138	unsigned long flags;
142	139	unsigned int key_size;
143	140
144	141
145	142
146	143
147	144
148	145
149	146
150	147
151	148
152	149
153	150
154	151
155	152
...	...	@@ -1032,90 +1029,102 @@
1032	1029	if (cc->dev)
1033	1030	dm_put_device(ti, cc->dev);
1034	1031
1035		- kfree(cc->iv_mode);
	1032	+ kzfree(cc->cipher);
	1033	+ kzfree(cc->cipher_mode);
1036	1034
1037	1035	/* Must zero key material before freeing */
1038	1036	kzfree(cc);
1039	1037	}
1040	1038
1041		-/*
1042		- * Construct an encryption mapping:
1043		- * <cipher> <key> <iv_offset> <dev_path> <start>
1044		- */
1045		-static int crypt_ctr(struct dm_target ti, unsigned int argc, char *argv)
	1039	+static int crypt_ctr_cipher(struct dm_target *ti,
	1040	+ char cipher_in, char key)
1046	1041	{
1047		- struct crypt_config *cc;
1048		- char *tmp;
1049		- char *cipher;
1050		- char *chainmode;
1051		- char *ivmode;
1052		- char *ivopts;
1053		- unsigned int key_size;
1054		- unsigned long long tmpll;
	1042	+ struct crypt_config *cc = ti->private;
	1043	+ char tmp, cipher, chainmode, ivmode, *ivopts;
	1044	+ char *cipher_api = NULL;
1055	1045	int ret = -EINVAL;
1056	1046
1057		- if (argc != 5) {
1058		- ti->error = "Not enough arguments";
	1047	+ /* Convert to crypto api definition? */
	1048	+ if (strchr(cipher_in, '(')) {
	1049	+ ti->error = "Bad cipher specification";
1059	1050	return -EINVAL;
1060	1051	}
1061	1052
1062		- tmp = argv[0];
	1053	+ /*
	1054	+ * Legacy dm-crypt cipher specification
	1055	+ * cipher-mode-iv:ivopts
	1056	+ */
	1057	+ tmp = cipher_in;
1063	1058	cipher = strsep(&tmp, "-");
	1059	+
	1060	+ cc->cipher = kstrdup(cipher, GFP_KERNEL);
	1061	+ if (!cc->cipher)
	1062	+ goto bad_mem;
	1063	+
	1064	+ if (tmp) {
	1065	+ cc->cipher_mode = kstrdup(tmp, GFP_KERNEL);
	1066	+ if (!cc->cipher_mode)
	1067	+ goto bad_mem;
	1068	+ }
	1069	+
1064	1070	chainmode = strsep(&tmp, "-");
1065	1071	ivopts = strsep(&tmp, "-");
1066	1072	ivmode = strsep(&ivopts, ":");
1067	1073
1068	1074	if (tmp)
1069		- DMWARN("Unexpected additional cipher options");
	1075	+ DMWARN("Ignoring unexpected additional cipher options");
1070	1076
1071		- key_size = strlen(argv[1]) >> 1;
1072		-
1073		- cc = kzalloc(sizeof(cc) + key_size sizeof(u8), GFP_KERNEL);
1074		- if (!cc) {
1075		- ti->error = "Cannot allocate transparent encryption context";
1076		- return -ENOMEM;
1077		- }
1078		-
1079		- ti->private = cc;
1080		-
1081		- /* Compatibility mode for old dm-crypt cipher strings */
1082		- if (!chainmode \|\| (strcmp(chainmode, "plain") == 0 && !ivmode)) {
	1077	+ /* Compatibility mode for old dm-crypt mappings */
	1078	+ if (!chainmode \|\| (!strcmp(chainmode, "plain") && !ivmode)) {
	1079	+ kfree(cc->cipher_mode);
	1080	+ cc->cipher_mode = kstrdup("cbc-plain", GFP_KERNEL);
1083	1081	chainmode = "cbc";
1084	1082	ivmode = "plain";
1085	1083	}
1086	1084
1087	1085	if (strcmp(chainmode, "ecb") && !ivmode) {
1088		- ti->error = "This chaining mode requires an IV mechanism";
1089		- goto bad;
	1086	+ ti->error = "IV mechanism required";
	1087	+ return -EINVAL;
1090	1088	}
1091	1089
1092		- ret = -ENOMEM;
1093		- if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1094		- chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
1095		- ti->error = "Chain mode + cipher name is too long";
1096		- goto bad;
	1090	+ cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
	1091	+ if (!cipher_api)
	1092	+ goto bad_mem;
	1093	+
	1094	+ ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
	1095	+ "%s(%s)", chainmode, cipher);
	1096	+ if (ret < 0) {
	1097	+ kfree(cipher_api);
	1098	+ goto bad_mem;
1097	1099	}
1098	1100
1099		- cc->tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
	1101	+ /* Allocate cipher */
	1102	+ cc->tfm = crypto_alloc_ablkcipher(cipher_api, 0, 0);
1100	1103	if (IS_ERR(cc->tfm)) {
	1104	+ ret = PTR_ERR(cc->tfm);
1101	1105	ti->error = "Error allocating crypto tfm";
1102	1106	goto bad;
1103	1107	}
1104	1108
1105		- strcpy(cc->cipher, cipher);
1106		- strcpy(cc->chainmode, chainmode);
1107		-
1108		- ret = crypt_set_key(cc, argv[1]);
	1109	+ /* Initialize and set key */
	1110	+ ret = crypt_set_key(cc, key);
1109	1111	if (ret < 0) {
1110	1112	ti->error = "Error decoding and setting key";
1111	1113	goto bad;
1112	1114	}
1113	1115
1114		- /*
1115		- * Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
1116		- * See comments at iv code
1117		- */
1118		- ret = -EINVAL;
	1116	+ /* Initialize IV */
	1117	+ cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
	1118	+ if (cc->iv_size)
	1119	+ /* at least a 64 bit sector number should fit in our buffer */
	1120	+ cc->iv_size = max(cc->iv_size,
	1121	+ (unsigned int)(sizeof(u64) / sizeof(u8)));
	1122	+ else if (ivmode) {
	1123	+ DMWARN("Selected cipher does not support IVs");
	1124	+ ivmode = NULL;
	1125	+ }
	1126	+
	1127	+ /* Choose ivmode, see comments at iv code. */
1119	1128	if (ivmode == NULL)
1120	1129	cc->iv_gen_ops = NULL;
1121	1130	else if (strcmp(ivmode, "plain") == 0)
...	...	@@ -1129,6 +1138,7 @@
1129	1138	else if (strcmp(ivmode, "null") == 0)
1130	1139	cc->iv_gen_ops = &crypt_iv_null_ops;
1131	1140	else {
	1141	+ ret = -EINVAL;
1132	1142	ti->error = "Invalid IV mode";
1133	1143	goto bad;
1134	1144	}
1135	1145
...	...	@@ -1151,20 +1161,45 @@
1151	1161	}
1152	1162	}
1153	1163
1154		- cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
1155		- if (cc->iv_size)
1156		- /* at least a 64 bit sector number should fit in our buffer */
1157		- cc->iv_size = max(cc->iv_size,
1158		- (unsigned int)(sizeof(u64) / sizeof(u8)));
1159		- else {
1160		- if (cc->iv_gen_ops) {
1161		- DMWARN("Selected cipher does not support IVs");
1162		- if (cc->iv_gen_ops->dtr)
1163		- cc->iv_gen_ops->dtr(cc);
1164		- cc->iv_gen_ops = NULL;
1165		- }
	1164	+ ret = 0;
	1165	+bad:
	1166	+ kfree(cipher_api);
	1167	+ return ret;
	1168	+
	1169	+bad_mem:
	1170	+ ti->error = "Cannot allocate cipher strings";
	1171	+ return -ENOMEM;
	1172	+}
	1173	+
	1174	+/*
	1175	+ * Construct an encryption mapping:
	1176	+ * <cipher> <key> <iv_offset> <dev_path> <start>
	1177	+ */
	1178	+static int crypt_ctr(struct dm_target ti, unsigned int argc, char *argv)
	1179	+{
	1180	+ struct crypt_config *cc;
	1181	+ unsigned int key_size;
	1182	+ unsigned long long tmpll;
	1183	+ int ret;
	1184	+
	1185	+ if (argc != 5) {
	1186	+ ti->error = "Not enough arguments";
	1187	+ return -EINVAL;
1166	1188	}
1167	1189
	1190	+ key_size = strlen(argv[1]) >> 1;
	1191	+
	1192	+ cc = kzalloc(sizeof(cc) + key_size sizeof(u8), GFP_KERNEL);
	1193	+ if (!cc) {
	1194	+ ti->error = "Cannot allocate encryption context";
	1195	+ return -ENOMEM;
	1196	+ }
	1197	+
	1198	+ ti->private = cc;
	1199	+ ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
	1200	+ if (ret < 0)
	1201	+ goto bad;
	1202	+
1168	1203	ret = -ENOMEM;
1169	1204	cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1170	1205	if (!cc->io_pool) {
...	...	@@ -1217,17 +1252,6 @@
1217	1252	cc->start = tmpll;
1218	1253
1219	1254	ret = -ENOMEM;
1220		- if (ivmode && cc->iv_gen_ops) {
1221		- if (ivopts)
1222		- *(ivopts - 1) = ':';
1223		- cc->iv_mode = kstrdup(ivmode, GFP_KERNEL);
1224		- if (!cc->iv_mode) {
1225		- ti->error = "Error kmallocing iv_mode string";
1226		- goto bad;
1227		- }
1228		- } else
1229		- cc->iv_mode = NULL;
1230		-
1231	1255	cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1232	1256	if (!cc->io_queue) {
1233	1257	ti->error = "Couldn't create kcryptd io queue";
...	...	@@ -1273,7 +1297,7 @@
1273	1297	static int crypt_status(struct dm_target *ti, status_type_t type,
1274	1298	char *result, unsigned int maxlen)
1275	1299	{
1276		- struct crypt_config cc = (struct crypt_config ) ti->private;
	1300	+ struct crypt_config *cc = ti->private;
1277	1301	unsigned int sz = 0;
1278	1302
1279	1303	switch (type) {
1280	1304
...	...	@@ -1282,11 +1306,10 @@
1282	1306	break;
1283	1307
1284	1308	case STATUSTYPE_TABLE:
1285		- if (cc->iv_mode)
1286		- DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
1287		- cc->iv_mode);
	1309	+ if (cc->cipher_mode)
	1310	+ DMEMIT("%s-%s ", cc->cipher, cc->cipher_mode);
1288	1311	else
1289		- DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
	1312	+ DMEMIT("%s ", cc->cipher);
1290	1313
1291	1314	if (cc->key_size > 0) {
1292	1315	if ((maxlen - sz) < ((cc->key_size << 1) + 1))