Merge tag 'for-5.3/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Add encrypted byte-offset initialization vector (eboiv) to DM crypt.

 - Add optional discard features to DM snapshot which allow freeing
   space from a DM device whose free space was exhausted.

 - Various small improvements to use struct_size() and kzalloc().

 - Fix to check if DM thin metadata is in fail_io mode before attempting
   to update the superblock to set the needs_check flag. Otherwise the
   DM thin-pool can hang.

 - Fix DM bufio shrinker's potential for ABBA recursion deadlock with DM
   thin provisioning on loop usecase.

* tag 'for-5.3/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm bufio: fix deadlock with loop device
  dm snapshot: add optional discard support features
  dm crypt: implement eboiv - encrypted byte-offset initialization vector
  dm crypt: remove obsolete comment about plumb IV
  dm crypt: wipe private IV struct after key invalid flag is set
  dm integrity: use kzalloc() instead of kmalloc() + memset()
  dm: update stale comment in end_clone_bio()
  dm log writes: fix incorrect comment about the logged sequence example
  dm log writes: use struct_size() to calculate size of pending_block
  dm crypt: use struct_size() when allocating encryption context
  dm integrity: always set version on superblock update
  dm thin metadata: check if in fail_io mode when setting needs_check

1 files changed, 90 insertions, 11 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 1b16d34bb785..d5216bcc4649 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -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;
@@ -291,8 +296,9 @@ static struct crypto_aead *any_tfm_aead(struct crypt_config *cc)
  *       Note that this encryption scheme is vulnerable to watermarking attacks
  *       and should be used for old compatible containers access only.
  *
- * plumb: unimplemented, see:
- * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
+ * 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,
@@ -841,6 +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
 };
@@ -893,6 +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
  */
@@ -2158,6 +2233,14 @@ static int crypt_wipe_key(struct crypt_config *cc)
 
 	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
 	get_random_bytes(&cc->key, cc->key_size);
+
+	/* Wipe IV private keys */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
+		r = cc->iv_gen_ops->wipe(cc);
+		if (r)
+			return r;
+	}
+
 	kzfree(cc->key_string);
 	cc->key_string = NULL;
 	r = crypt_setkey(cc);
@@ -2288,6 +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;
 		/*
@@ -2699,7 +2784,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		return -EINVAL;
 	}
 
-	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
+	cc = kzalloc(struct_size(cc, key, key_size), GFP_KERNEL);
 	if (!cc) {
 		ti->error = "Cannot allocate encryption context";
 		return -ENOMEM;
@@ -3050,14 +3135,8 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv,
 				memset(cc->key, 0, cc->key_size * sizeof(u8));
 			return ret;
 		}
-		if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
-			if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
-				ret = cc->iv_gen_ops->wipe(cc);
-				if (ret)
-					return ret;
-			}
+		if (argc == 2 && !strcasecmp(argv[1], "wipe"))
 			return crypt_wipe_key(cc);
-		}
 	}
 
 error:
@@ -3094,7 +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,