dm crypt: implement eboiv - encrypted byte-offset initialization vector (b9411d73) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/md/dm-crypt.c

+81 −1

Original line number	Diff line number	Diff line
		@@ -120,6 +120,10 @@ struct iv_tcw_private {
		u8 *whitening;
		};

		struct iv_eboiv_private {
		struct crypto_cipher *tfm;
		};

		/*
		* Crypt: maps a linear range of a block device
		* and encrypts / decrypts at the same time.
		@@ -159,6 +163,7 @@ struct crypt_config {
		struct iv_benbi_private benbi;
		struct iv_lmk_private lmk;
		struct iv_tcw_private tcw;
		struct iv_eboiv_private eboiv;
		} iv_gen_private;
		u64 iv_offset;
		unsigned int iv_size;
		@@ -290,6 +295,10 @@ static struct crypto_aead any_tfm_aead(struct crypt_config cc)
		* is calculated from initial key, sector number and mixed using CRC32.
		* Note that this encryption scheme is vulnerable to watermarking attacks
		* and should be used for old compatible containers access only.
		*
		* eboiv: Encrypted byte-offset IV (used in Bitlocker in CBC mode)
		* The IV is encrypted little-endian byte-offset (with the same key
		* and cipher as the volume).
		*/

		static int crypt_iv_plain_gen(struct crypt_config cc, u8 iv,
		@@ -838,6 +847,67 @@ static int crypt_iv_random_gen(struct crypt_config cc, u8 iv,
		return 0;
		}

		static void crypt_iv_eboiv_dtr(struct crypt_config *cc)
		{
		struct iv_eboiv_private *eboiv = &cc->iv_gen_private.eboiv;

		crypto_free_cipher(eboiv->tfm);
		eboiv->tfm = NULL;
		}

		static int crypt_iv_eboiv_ctr(struct crypt_config cc, struct dm_target ti,
		const char *opts)
		{
		struct iv_eboiv_private *eboiv = &cc->iv_gen_private.eboiv;
		struct crypto_cipher *tfm;

		tfm = crypto_alloc_cipher(cc->cipher, 0, 0);
		if (IS_ERR(tfm)) {
		ti->error = "Error allocating crypto tfm for EBOIV";
		return PTR_ERR(tfm);
		}

		if (crypto_cipher_blocksize(tfm) != cc->iv_size) {
		ti->error = "Block size of EBOIV cipher does "
		"not match IV size of block cipher";
		crypto_free_cipher(tfm);
		return -EINVAL;
		}

		eboiv->tfm = tfm;
		return 0;
		}

		static int crypt_iv_eboiv_init(struct crypt_config *cc)
		{
		struct iv_eboiv_private *eboiv = &cc->iv_gen_private.eboiv;
		int err;

		err = crypto_cipher_setkey(eboiv->tfm, cc->key, cc->key_size);
		if (err)
		return err;

		return 0;
		}

		static int crypt_iv_eboiv_wipe(struct crypt_config *cc)
		{
		/* Called after cc->key is set to random key in crypt_wipe() */
		return crypt_iv_eboiv_init(cc);
		}

		static int crypt_iv_eboiv_gen(struct crypt_config cc, u8 iv,
		struct dm_crypt_request *dmreq)
		{
		struct iv_eboiv_private *eboiv = &cc->iv_gen_private.eboiv;

		memset(iv, 0, cc->iv_size);
		(__le64 )iv = cpu_to_le64(dmreq->iv_sector * cc->sector_size);
		crypto_cipher_encrypt_one(eboiv->tfm, iv, iv);

		return 0;
		}

		static const struct crypt_iv_operations crypt_iv_plain_ops = {
		.generator = crypt_iv_plain_gen
		};
		@@ -890,6 +960,14 @@ static struct crypt_iv_operations crypt_iv_random_ops = {
		.generator = crypt_iv_random_gen
		};

		static struct crypt_iv_operations crypt_iv_eboiv_ops = {
		.ctr = crypt_iv_eboiv_ctr,
		.dtr = crypt_iv_eboiv_dtr,
		.init = crypt_iv_eboiv_init,
		.wipe = crypt_iv_eboiv_wipe,
		.generator = crypt_iv_eboiv_gen
		};

		/*
		* Integrity extensions
		*/
		@@ -2293,6 +2371,8 @@ static int crypt_ctr_ivmode(struct dm_target ti, const char ivmode)
		cc->iv_gen_ops = &crypt_iv_benbi_ops;
		else if (strcmp(ivmode, "null") == 0)
		cc->iv_gen_ops = &crypt_iv_null_ops;
		else if (strcmp(ivmode, "eboiv") == 0)
		cc->iv_gen_ops = &crypt_iv_eboiv_ops;
		else if (strcmp(ivmode, "lmk") == 0) {
		cc->iv_gen_ops = &crypt_iv_lmk_ops;
		/*
		@@ -3093,7 +3173,7 @@ static void crypt_io_hints(struct dm_target ti, struct queue_limits limits)

		static struct target_type crypt_target = {
		.name = "crypt",
		.version = {1, 18, 1},
		.version = {1, 19, 0},
		.module = THIS_MODULE,
		.ctr = crypt_ctr,
		.dtr = crypt_dtr,