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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>
This commit is contained in:
Milan Broz
Alasdair G Kergon
parent
28513fccf0
commit
5ebaee6d29
@ -107,11 +107,10 @@ struct crypt_config {
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struct workqueue_struct *io_queue;
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struct workqueue_struct *crypt_queue;
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/*
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* crypto related data
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*/
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char *cipher;
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char *cipher_mode;
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struct crypt_iv_operations *iv_gen_ops;
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char *iv_mode;
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union {
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struct iv_essiv_private essiv;
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struct iv_benbi_private benbi;
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@ -135,8 +134,6 @@ struct crypt_config {
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unsigned int dmreq_start;
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struct ablkcipher_request *req;
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char cipher[CRYPTO_MAX_ALG_NAME];
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char chainmode[CRYPTO_MAX_ALG_NAME];
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struct crypto_ablkcipher *tfm;
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unsigned long flags;
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unsigned int key_size;
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@ -1032,90 +1029,102 @@ static void crypt_dtr(struct dm_target *ti)
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if (cc->dev)
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dm_put_device(ti, cc->dev);
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kfree(cc->iv_mode);
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kzfree(cc->cipher);
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kzfree(cc->cipher_mode);
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/* Must zero key material before freeing */
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kzfree(cc);
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}
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/*
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* Construct an encryption mapping:
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* <cipher> <key> <iv_offset> <dev_path> <start>
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*/
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static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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static int crypt_ctr_cipher(struct dm_target *ti,
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char *cipher_in, char *key)
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{
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struct crypt_config *cc;
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char *tmp;
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char *cipher;
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char *chainmode;
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char *ivmode;
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char *ivopts;
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unsigned int key_size;
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unsigned long long tmpll;
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struct crypt_config *cc = ti->private;
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char *tmp, *cipher, *chainmode, *ivmode, *ivopts;
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char *cipher_api = NULL;
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int ret = -EINVAL;
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if (argc != 5) {
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ti->error = "Not enough arguments";
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/* Convert to crypto api definition? */
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if (strchr(cipher_in, '(')) {
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ti->error = "Bad cipher specification";
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return -EINVAL;
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}
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tmp = argv[0];
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/*
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* Legacy dm-crypt cipher specification
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* cipher-mode-iv:ivopts
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*/
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tmp = cipher_in;
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cipher = strsep(&tmp, "-");
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cc->cipher = kstrdup(cipher, GFP_KERNEL);
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if (!cc->cipher)
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goto bad_mem;
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if (tmp) {
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cc->cipher_mode = kstrdup(tmp, GFP_KERNEL);
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if (!cc->cipher_mode)
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goto bad_mem;
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}
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chainmode = strsep(&tmp, "-");
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ivopts = strsep(&tmp, "-");
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ivmode = strsep(&ivopts, ":");
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if (tmp)
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DMWARN("Unexpected additional cipher options");
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DMWARN("Ignoring unexpected additional cipher options");
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key_size = strlen(argv[1]) >> 1;
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cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
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if (!cc) {
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ti->error = "Cannot allocate transparent encryption context";
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return -ENOMEM;
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}
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ti->private = cc;
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/* Compatibility mode for old dm-crypt cipher strings */
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if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
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/* Compatibility mode for old dm-crypt mappings */
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if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
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kfree(cc->cipher_mode);
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cc->cipher_mode = kstrdup("cbc-plain", GFP_KERNEL);
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chainmode = "cbc";
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ivmode = "plain";
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}
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if (strcmp(chainmode, "ecb") && !ivmode) {
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ti->error = "This chaining mode requires an IV mechanism";
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goto bad;
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ti->error = "IV mechanism required";
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return -EINVAL;
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}
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ret = -ENOMEM;
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if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
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chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
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ti->error = "Chain mode + cipher name is too long";
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goto bad;
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cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
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if (!cipher_api)
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goto bad_mem;
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ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
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"%s(%s)", chainmode, cipher);
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if (ret < 0) {
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kfree(cipher_api);
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goto bad_mem;
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}
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cc->tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
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/* Allocate cipher */
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cc->tfm = crypto_alloc_ablkcipher(cipher_api, 0, 0);
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if (IS_ERR(cc->tfm)) {
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ret = PTR_ERR(cc->tfm);
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ti->error = "Error allocating crypto tfm";
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goto bad;
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}
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strcpy(cc->cipher, cipher);
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strcpy(cc->chainmode, chainmode);
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ret = crypt_set_key(cc, argv[1]);
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/* Initialize and set key */
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ret = crypt_set_key(cc, key);
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if (ret < 0) {
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ti->error = "Error decoding and setting key";
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goto bad;
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}
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/*
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* Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
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* See comments at iv code
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*/
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ret = -EINVAL;
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/* Initialize IV */
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cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
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if (cc->iv_size)
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/* at least a 64 bit sector number should fit in our buffer */
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cc->iv_size = max(cc->iv_size,
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(unsigned int)(sizeof(u64) / sizeof(u8)));
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else if (ivmode) {
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DMWARN("Selected cipher does not support IVs");
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ivmode = NULL;
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}
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/* Choose ivmode, see comments at iv code. */
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if (ivmode == NULL)
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cc->iv_gen_ops = NULL;
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else if (strcmp(ivmode, "plain") == 0)
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@ -1129,6 +1138,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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else if (strcmp(ivmode, "null") == 0)
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cc->iv_gen_ops = &crypt_iv_null_ops;
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else {
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ret = -EINVAL;
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ti->error = "Invalid IV mode";
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goto bad;
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}
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@ -1151,20 +1161,45 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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}
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}
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cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
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if (cc->iv_size)
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/* at least a 64 bit sector number should fit in our buffer */
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cc->iv_size = max(cc->iv_size,
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(unsigned int)(sizeof(u64) / sizeof(u8)));
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else {
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if (cc->iv_gen_ops) {
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DMWARN("Selected cipher does not support IVs");
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if (cc->iv_gen_ops->dtr)
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cc->iv_gen_ops->dtr(cc);
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cc->iv_gen_ops = NULL;
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}
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ret = 0;
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bad:
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kfree(cipher_api);
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return ret;
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bad_mem:
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ti->error = "Cannot allocate cipher strings";
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return -ENOMEM;
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}
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/*
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* Construct an encryption mapping:
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* <cipher> <key> <iv_offset> <dev_path> <start>
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*/
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static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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{
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struct crypt_config *cc;
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unsigned int key_size;
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unsigned long long tmpll;
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int ret;
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if (argc != 5) {
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ti->error = "Not enough arguments";
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return -EINVAL;
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}
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key_size = strlen(argv[1]) >> 1;
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cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
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if (!cc) {
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ti->error = "Cannot allocate encryption context";
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return -ENOMEM;
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}
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ti->private = cc;
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ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
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if (ret < 0)
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goto bad;
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ret = -ENOMEM;
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cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
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if (!cc->io_pool) {
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@ -1217,17 +1252,6 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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cc->start = tmpll;
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ret = -ENOMEM;
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if (ivmode && cc->iv_gen_ops) {
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if (ivopts)
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*(ivopts - 1) = ':';
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cc->iv_mode = kstrdup(ivmode, GFP_KERNEL);
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if (!cc->iv_mode) {
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ti->error = "Error kmallocing iv_mode string";
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goto bad;
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}
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} else
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cc->iv_mode = NULL;
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cc->io_queue = create_singlethread_workqueue("kcryptd_io");
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if (!cc->io_queue) {
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ti->error = "Couldn't create kcryptd io queue";
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@ -1273,7 +1297,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
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static int crypt_status(struct dm_target *ti, status_type_t type,
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char *result, unsigned int maxlen)
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{
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struct crypt_config *cc = (struct crypt_config *) ti->private;
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struct crypt_config *cc = ti->private;
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unsigned int sz = 0;
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switch (type) {
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@ -1282,11 +1306,10 @@ static int crypt_status(struct dm_target *ti, status_type_t type,
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break;
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case STATUSTYPE_TABLE:
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if (cc->iv_mode)
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DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
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cc->iv_mode);
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if (cc->cipher_mode)
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DMEMIT("%s-%s ", cc->cipher, cc->cipher_mode);
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else
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DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
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DMEMIT("%s ", cc->cipher);
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if (cc->key_size > 0) {
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if ((maxlen - sz) < ((cc->key_size << 1) + 1))
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