6 files changed, 257 insertions, 65 deletions

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 8371e4e1f596..c1d92074b65c 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -12,6 +12,7 @@
 #define _FSCRYPT_PRIVATE_H
 
 #include <linux/fscrypt.h>
+#include <linux/minmax.h>
 #include <linux/siphash.h>
 #include <crypto/hash.h>
 #include <linux/blk-crypto.h>
@@ -27,6 +28,23 @@
  */
 #define FSCRYPT_MIN_KEY_SIZE	16
 
+/* Maximum size of a raw fscrypt master key */
+#define FSCRYPT_MAX_RAW_KEY_SIZE	64
+
+/* Maximum size of a hardware-wrapped fscrypt master key */
+#define FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE	BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE
+
+/* Maximum size of an fscrypt master key across both key types */
+#define FSCRYPT_MAX_ANY_KEY_SIZE \
+	MAX(FSCRYPT_MAX_RAW_KEY_SIZE, FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE)
+
+/*
+ * FSCRYPT_MAX_KEY_SIZE is defined in the UAPI header, but the addition of
+ * hardware-wrapped keys has made it misleading as it's only for raw keys.
+ * Don't use it in kernel code; use one of the above constants instead.
+ */
+#undef FSCRYPT_MAX_KEY_SIZE
+
 #define FSCRYPT_CONTEXT_V1	1
 #define FSCRYPT_CONTEXT_V2	2
 
@@ -360,13 +378,15 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
  * outputs are unique and cryptographically isolated, i.e. knowledge of one
  * output doesn't reveal another.
  */
-#define HKDF_CONTEXT_KEY_IDENTIFIER	1 /* info=<empty>		*/
+#define HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY	1 /* info=<empty>	*/
 #define HKDF_CONTEXT_PER_FILE_ENC_KEY	2 /* info=file_nonce		*/
 #define HKDF_CONTEXT_DIRECT_KEY		3 /* info=mode_num		*/
 #define HKDF_CONTEXT_IV_INO_LBLK_64_KEY	4 /* info=mode_num||fs_uuid	*/
 #define HKDF_CONTEXT_DIRHASH_KEY	5 /* info=file_nonce		*/
 #define HKDF_CONTEXT_IV_INO_LBLK_32_KEY	6 /* info=mode_num||fs_uuid	*/
 #define HKDF_CONTEXT_INODE_HASH_KEY	7 /* info=<empty>		*/
+#define HKDF_CONTEXT_KEY_IDENTIFIER_FOR_HW_WRAPPED_KEY \
+					8 /* info=<empty>		*/
 
 int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context,
 			const u8 *info, unsigned int infolen,
@@ -376,7 +396,8 @@ void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
 
 /* inline_crypt.c */
 #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
-int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci);
+int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,
+				   bool is_hw_wrapped_key);
 
 static inline bool
 fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
@@ -385,12 +406,17 @@ fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
 }
 
 int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
-				     const u8 *raw_key,
+				     const u8 *key_bytes, size_t key_size,
+				     bool is_hw_wrapped,
 				     const struct fscrypt_inode_info *ci);
 
 void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
 				      struct fscrypt_prepared_key *prep_key);
 
+int fscrypt_derive_sw_secret(struct super_block *sb,
+			     const u8 *wrapped_key, size_t wrapped_key_size,
+			     u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]);
+
 /*
  * Check whether the crypto transform or blk-crypto key has been allocated in
  * @prep_key, depending on which encryption implementation the file will use.
@@ -414,7 +440,8 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
 
 #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 
-static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci)
+static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,
+						 bool is_hw_wrapped_key)
 {
 	return 0;
 }
@@ -427,7 +454,8 @@ fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci)
 
 static inline int
 fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
-				 const u8 *raw_key,
+				 const u8 *key_bytes, size_t key_size,
+				 bool is_hw_wrapped,
 				 const struct fscrypt_inode_info *ci)
 {
 	WARN_ON_ONCE(1);
@@ -440,6 +468,15 @@ fscrypt_destroy_inline_crypt_key(struct super_block *sb,
 {
 }
 
+static inline int
+fscrypt_derive_sw_secret(struct super_block *sb,
+			 const u8 *wrapped_key, size_t wrapped_key_size,
+			 u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE])
+{
+	fscrypt_warn(NULL, "kernel doesn't support hardware-wrapped keys");
+	return -EOPNOTSUPP;
+}
+
 static inline bool
 fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
 			const struct fscrypt_inode_info *ci)
@@ -456,20 +493,38 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
 struct fscrypt_master_key_secret {
 
 	/*
-	 * For v2 policy keys: HKDF context keyed by this master key.
-	 * For v1 policy keys: not set (hkdf.hmac_tfm == NULL).
+	 * The KDF with which subkeys of this key can be derived.
+	 *
+	 * For v1 policy keys, this isn't applicable and won't be set.
+	 * Otherwise, this KDF will be keyed by this master key if
+	 * ->is_hw_wrapped=false, or by the "software secret" that hardware
+	 * derived from this master key if ->is_hw_wrapped=true.
 	 */
 	struct fscrypt_hkdf	hkdf;
 
 	/*
-	 * Size of the raw key in bytes.  This remains set even if ->raw was
+	 * True if this key is a hardware-wrapped key; false if this key is a
+	 * raw key (i.e. a "software key").  For v1 policy keys this will always
+	 * be false, as v1 policy support is a legacy feature which doesn't
+	 * support newer functionality such as hardware-wrapped keys.
+	 */
+	bool			is_hw_wrapped;
+
+	/*
+	 * Size of the key in bytes.  This remains set even if ->bytes was
 	 * zeroized due to no longer being needed.  I.e. we still remember the
 	 * size of the key even if we don't need to remember the key itself.
 	 */
 	u32			size;
 
-	/* For v1 policy keys: the raw key.  Wiped for v2 policy keys. */
-	u8			raw[FSCRYPT_MAX_KEY_SIZE];
+	/*
+	 * The bytes of the key, when still needed.  This can be either a raw
+	 * key or a hardware-wrapped key, as indicated by ->is_hw_wrapped.  In
+	 * the case of a raw, v2 policy key, there is no need to remember the
+	 * actual key separately from ->hkdf so this field will be zeroized as
+	 * soon as ->hkdf is initialized.
+	 */
+	u8			bytes[FSCRYPT_MAX_ANY_KEY_SIZE];
 
 } __randomize_layout;
 
diff --git a/fs/crypto/hkdf.c b/fs/crypto/hkdf.c
index 855a0f4b7318..0f3028adc9c7 100644
--- a/fs/crypto/hkdf.c
+++ b/fs/crypto/hkdf.c
@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This is used to derive keys from the fscrypt master keys.
+ * This is used to derive keys from the fscrypt master keys (or from the
+ * "software secrets" which hardware derives from the fscrypt master keys, in
+ * the case that the fscrypt master keys are hardware-wrapped keys).
  *
  * Copyright 2019 Google LLC
  */
diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index 7fa53d30aec3..1d008c440cb6 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -89,7 +89,8 @@ static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode *mode,
 }
 
 /* Enable inline encryption for this file if supported. */
-int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci)
+int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,
+				   bool is_hw_wrapped_key)
 {
 	const struct inode *inode = ci->ci_inode;
 	struct super_block *sb = inode->i_sb;
@@ -130,7 +131,8 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci)
 	crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode;
 	crypto_cfg.data_unit_size = 1U << ci->ci_data_unit_bits;
 	crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci);
-	crypto_cfg.key_type = BLK_CRYPTO_KEY_TYPE_RAW;
+	crypto_cfg.key_type = is_hw_wrapped_key ?
+		BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;
 
 	devs = fscrypt_get_devices(sb, &num_devs);
 	if (IS_ERR(devs))
@@ -151,12 +153,15 @@ out_free_devs:
 }
 
 int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
-				     const u8 *raw_key,
+				     const u8 *key_bytes, size_t key_size,
+				     bool is_hw_wrapped,
 				     const struct fscrypt_inode_info *ci)
 {
 	const struct inode *inode = ci->ci_inode;
 	struct super_block *sb = inode->i_sb;
 	enum blk_crypto_mode_num crypto_mode = ci->ci_mode->blk_crypto_mode;
+	enum blk_crypto_key_type key_type = is_hw_wrapped ?
+		BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;
 	struct blk_crypto_key *blk_key;
 	struct block_device **devs;
 	unsigned int num_devs;
@@ -167,9 +172,8 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 	if (!blk_key)
 		return -ENOMEM;
 
-	err = blk_crypto_init_key(blk_key, raw_key, ci->ci_mode->keysize,
-				  BLK_CRYPTO_KEY_TYPE_RAW, crypto_mode,
-				  fscrypt_get_dun_bytes(ci),
+	err = blk_crypto_init_key(blk_key, key_bytes, key_size, key_type,
+				  crypto_mode, fscrypt_get_dun_bytes(ci),
 				  1U << ci->ci_data_unit_bits);
 	if (err) {
 		fscrypt_err(inode, "error %d initializing blk-crypto key", err);
@@ -228,6 +232,34 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
 	kfree_sensitive(blk_key);
 }
 
+/*
+ * Ask the inline encryption hardware to derive the software secret from a
+ * hardware-wrapped key.  Returns -EOPNOTSUPP if hardware-wrapped keys aren't
+ * supported on this filesystem or hardware.
+ */
+int fscrypt_derive_sw_secret(struct super_block *sb,
+			     const u8 *wrapped_key, size_t wrapped_key_size,
+			     u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE])
+{
+	int err;
+
+	/* The filesystem must be mounted with -o inlinecrypt. */
+	if (!(sb->s_flags & SB_INLINECRYPT)) {
+		fscrypt_warn(NULL,
+			     "%s: filesystem not mounted with inlinecrypt\n",
+			     sb->s_id);
+		return -EOPNOTSUPP;
+	}
+
+	err = blk_crypto_derive_sw_secret(sb->s_bdev, wrapped_key,
+					  wrapped_key_size, sw_secret);
+	if (err == -EOPNOTSUPP)
+		fscrypt_warn(NULL,
+			     "%s: block device doesn't support hardware-wrapped keys\n",
+			     sb->s_id);
+	return err;
+}
+
 bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
 {
 	return inode->i_crypt_info->ci_inlinecrypt;
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 787e9c8938ba..ace369f13068 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -149,11 +149,11 @@ static int fscrypt_user_key_instantiate(struct key *key,
 					struct key_preparsed_payload *prep)
 {
 	/*
-	 * We just charge FSCRYPT_MAX_KEY_SIZE bytes to the user's key quota for
-	 * each key, regardless of the exact key size.  The amount of memory
+	 * We just charge FSCRYPT_MAX_RAW_KEY_SIZE bytes to the user's key quota
+	 * for each key, regardless of the exact key size.  The amount of memory
 	 * actually used is greater than the size of the raw key anyway.
 	 */
-	return key_payload_reserve(key, FSCRYPT_MAX_KEY_SIZE);
+	return key_payload_reserve(key, FSCRYPT_MAX_RAW_KEY_SIZE);
 }
 
 static void fscrypt_user_key_describe(const struct key *key, struct seq_file *m)
@@ -558,20 +558,45 @@ static int add_master_key(struct super_block *sb,
 	int err;
 
 	if (key_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
-		err = fscrypt_init_hkdf(&secret->hkdf, secret->raw,
-					secret->size);
-		if (err)
-			return err;
+		u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE];
+		u8 *kdf_key = secret->bytes;
+		unsigned int kdf_key_size = secret->size;
+		u8 keyid_kdf_ctx = HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY;
 
 		/*
-		 * Now that the HKDF context is initialized, the raw key is no
-		 * longer needed.
+		 * For raw keys, the fscrypt master key is used directly as the
+		 * fscrypt KDF key.  For hardware-wrapped keys, we have to pass
+		 * the master key to the hardware to derive the KDF key, which
+		 * is then only used to derive non-file-contents subkeys.
+		 */
+		if (secret->is_hw_wrapped) {
+			err = fscrypt_derive_sw_secret(sb, secret->bytes,
+						       secret->size, sw_secret);
+			if (err)
+				return err;
+			kdf_key = sw_secret;
+			kdf_key_size = sizeof(sw_secret);
+			/*
+			 * To avoid weird behavior if someone manages to
+			 * determine sw_secret and add it as a raw key, ensure
+			 * that hardware-wrapped keys and raw keys will have
+			 * different key identifiers by deriving their key
+			 * identifiers using different KDF contexts.
+			 */
+			keyid_kdf_ctx =
+				HKDF_CONTEXT_KEY_IDENTIFIER_FOR_HW_WRAPPED_KEY;
+		}
+		err = fscrypt_init_hkdf(&secret->hkdf, kdf_key, kdf_key_size);
+		/*
+		 * Now that the KDF context is initialized, the raw KDF key is
+		 * no longer needed.
 		 */
-		memzero_explicit(secret->raw, secret->size);
+		memzero_explicit(kdf_key, kdf_key_size);
+		if (err)
+			return err;
 
 		/* Calculate the key identifier */
-		err = fscrypt_hkdf_expand(&secret->hkdf,
-					  HKDF_CONTEXT_KEY_IDENTIFIER, NULL, 0,
+		err = fscrypt_hkdf_expand(&secret->hkdf, keyid_kdf_ctx, NULL, 0,
 					  key_spec->u.identifier,
 					  FSCRYPT_KEY_IDENTIFIER_SIZE);
 		if (err)
@@ -580,19 +605,36 @@ static int add_master_key(struct super_block *sb,
 	return do_add_master_key(sb, secret, key_spec);
 }
 
+/*
+ * Validate the size of an fscrypt master key being added.  Note that this is
+ * just an initial check, as we don't know which ciphers will be used yet.
+ * There is a stricter size check later when the key is actually used by a file.
+ */
+static inline bool fscrypt_valid_key_size(size_t size, u32 add_key_flags)
+{
+	u32 max_size = (add_key_flags & FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED) ?
+		       FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE :
+		       FSCRYPT_MAX_RAW_KEY_SIZE;
+
+	return size >= FSCRYPT_MIN_KEY_SIZE && size <= max_size;
+}
+
 static int fscrypt_provisioning_key_preparse(struct key_preparsed_payload *prep)
 {
 	const struct fscrypt_provisioning_key_payload *payload = prep->data;
 
-	if (prep->datalen < sizeof(*payload) + FSCRYPT_MIN_KEY_SIZE ||
-	    prep->datalen > sizeof(*payload) + FSCRYPT_MAX_KEY_SIZE)
+	if (prep->datalen < sizeof(*payload))
+		return -EINVAL;
+
+	if (!fscrypt_valid_key_size(prep->datalen - sizeof(*payload),
+				    payload->flags))
 		return -EINVAL;
 
 	if (payload->type != FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
 	    payload->type != FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER)
 		return -EINVAL;
 
-	if (payload->__reserved)
+	if (payload->flags & ~FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED)
 		return -EINVAL;
 
 	prep->payload.data[0] = kmemdup(payload, prep->datalen, GFP_KERNEL);
@@ -636,21 +678,21 @@ static struct key_type key_type_fscrypt_provisioning = {
 };
 
 /*
- * Retrieve the raw key from the Linux keyring key specified by 'key_id', and
- * store it into 'secret'.
+ * Retrieve the key from the Linux keyring key specified by 'key_id', and store
+ * it into 'secret'.
  *
- * The key must be of type "fscrypt-provisioning" and must have the field
- * fscrypt_provisioning_key_payload::type set to 'type', indicating that it's
- * only usable with fscrypt with the particular KDF version identified by
- * 'type'.  We don't use the "logon" key type because there's no way to
- * completely restrict the use of such keys; they can be used by any kernel API
- * that accepts "logon" keys and doesn't require a specific service prefix.
+ * The key must be of type "fscrypt-provisioning" and must have the 'type' and
+ * 'flags' field of the payload set to the given values, indicating that the key
+ * is intended for use for the specified purpose.  We don't use the "logon" key
+ * type because there's no way to completely restrict the use of such keys; they
+ * can be used by any kernel API that accepts "logon" keys and doesn't require a
+ * specific service prefix.
  *
  * The ability to specify the key via Linux keyring key is intended for cases
  * where userspace needs to re-add keys after the filesystem is unmounted and
- * re-mounted.  Most users should just provide the raw key directly instead.
+ * re-mounted.  Most users should just provide the key directly instead.
  */
-static int get_keyring_key(u32 key_id, u32 type,
+static int get_keyring_key(u32 key_id, u32 type, u32 flags,
 			   struct fscrypt_master_key_secret *secret)
 {
 	key_ref_t ref;
@@ -667,12 +709,16 @@ static int get_keyring_key(u32 key_id, u32 type,
 		goto bad_key;
 	payload = key->payload.data[0];
 
-	/* Don't allow fscrypt v1 keys to be used as v2 keys and vice versa. */
-	if (payload->type != type)
+	/*
+	 * Don't allow fscrypt v1 keys to be used as v2 keys and vice versa.
+	 * Similarly, don't allow hardware-wrapped keys to be used as
+	 * non-hardware-wrapped keys and vice versa.
+	 */
+	if (payload->type != type || payload->flags != flags)
 		goto bad_key;
 
 	secret->size = key->datalen - sizeof(*payload);
-	memcpy(secret->raw, payload->raw, secret->size);
+	memcpy(secret->bytes, payload->raw, secret->size);
 	err = 0;
 	goto out_put;
 
@@ -734,19 +780,28 @@ int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg)
 		return -EACCES;
 
 	memset(&secret, 0, sizeof(secret));
+
+	if (arg.flags) {
+		if (arg.flags & ~FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED)
+			return -EINVAL;
+		if (arg.key_spec.type != FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER)
+			return -EINVAL;
+		secret.is_hw_wrapped = true;
+	}
+
 	if (arg.key_id) {
 		if (arg.raw_size != 0)
 			return -EINVAL;
-		err = get_keyring_key(arg.key_id, arg.key_spec.type, &secret);
+		err = get_keyring_key(arg.key_id, arg.key_spec.type, arg.flags,
+				      &secret);
 		if (err)
 			goto out_wipe_secret;
 	} else {
-		if (arg.raw_size < FSCRYPT_MIN_KEY_SIZE ||
-		    arg.raw_size > FSCRYPT_MAX_KEY_SIZE)
+		if (!fscrypt_valid_key_size(arg.raw_size, arg.flags))
 			return -EINVAL;
 		secret.size = arg.raw_size;
 		err = -EFAULT;
-		if (copy_from_user(secret.raw, uarg->raw, secret.size))
+		if (copy_from_user(secret.bytes, uarg->raw, secret.size))
 			goto out_wipe_secret;
 	}
 
@@ -770,13 +825,13 @@ EXPORT_SYMBOL_GPL(fscrypt_ioctl_add_key);
 static void
 fscrypt_get_test_dummy_secret(struct fscrypt_master_key_secret *secret)
 {
-	static u8 test_key[FSCRYPT_MAX_KEY_SIZE];
+	static u8 test_key[FSCRYPT_MAX_RAW_KEY_SIZE];
 
-	get_random_once(test_key, FSCRYPT_MAX_KEY_SIZE);
+	get_random_once(test_key, sizeof(test_key));
 
 	memset(secret, 0, sizeof(*secret));
-	secret->size = FSCRYPT_MAX_KEY_SIZE;
-	memcpy(secret->raw, test_key, FSCRYPT_MAX_KEY_SIZE);
+	secret->size = sizeof(test_key);
+	memcpy(secret->bytes, test_key, sizeof(test_key));
 }
 
 int fscrypt_get_test_dummy_key_identifier(
@@ -787,10 +842,11 @@ int fscrypt_get_test_dummy_key_identifier(
 
 	fscrypt_get_test_dummy_secret(&secret);
 
-	err = fscrypt_init_hkdf(&secret.hkdf, secret.raw, secret.size);
+	err = fscrypt_init_hkdf(&secret.hkdf, secret.bytes, secret.size);
 	if (err)
 		goto out;
-	err = fscrypt_hkdf_expand(&secret.hkdf, HKDF_CONTEXT_KEY_IDENTIFIER,
+	err = fscrypt_hkdf_expand(&secret.hkdf,
+				  HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY,
 				  NULL, 0, key_identifier,
 				  FSCRYPT_KEY_IDENTIFIER_SIZE);
 out:
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index b4fe01ea4bd4..0d71843af946 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -153,7 +153,9 @@ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key,
 	struct crypto_skcipher *tfm;
 
 	if (fscrypt_using_inline_encryption(ci))
-		return fscrypt_prepare_inline_crypt_key(prep_key, raw_key, ci);
+		return fscrypt_prepare_inline_crypt_key(prep_key, raw_key,
+							ci->ci_mode->keysize,
+							false, ci);
 
 	tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode);
 	if (IS_ERR(tfm))
@@ -195,14 +197,29 @@ static int setup_per_mode_enc_key(struct fscrypt_inode_info *ci,
 	struct fscrypt_mode *mode = ci->ci_mode;
 	const u8 mode_num = mode - fscrypt_modes;
 	struct fscrypt_prepared_key *prep_key;
-	u8 mode_key[FSCRYPT_MAX_KEY_SIZE];
+	u8 mode_key[FSCRYPT_MAX_RAW_KEY_SIZE];
 	u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];
 	unsigned int hkdf_infolen = 0;
+	bool use_hw_wrapped_key = false;
 	int err;
 
 	if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX))
 		return -EINVAL;
 
+	if (mk->mk_secret.is_hw_wrapped && S_ISREG(inode->i_mode)) {
+		/* Using a hardware-wrapped key for file contents encryption */
+		if (!fscrypt_using_inline_encryption(ci)) {
+			if (sb->s_flags & SB_INLINECRYPT)
+				fscrypt_warn(ci->ci_inode,
+					     "Hardware-wrapped key required, but no suitable inline encryption capabilities are available");
+			else
+				fscrypt_warn(ci->ci_inode,
+					     "Hardware-wrapped keys require inline encryption (-o inlinecrypt)");
+			return -EINVAL;
+		}
+		use_hw_wrapped_key = true;
+	}
+
 	prep_key = &keys[mode_num];
 	if (fscrypt_is_key_prepared(prep_key, ci)) {
 		ci->ci_enc_key = *prep_key;
@@ -214,6 +231,16 @@ static int setup_per_mode_enc_key(struct fscrypt_inode_info *ci,
 	if (fscrypt_is_key_prepared(prep_key, ci))
 		goto done_unlock;
 
+	if (use_hw_wrapped_key) {
+		err = fscrypt_prepare_inline_crypt_key(prep_key,
+						       mk->mk_secret.bytes,
+						       mk->mk_secret.size, true,
+						       ci);
+		if (err)
+			goto out_unlock;
+		goto done_unlock;
+	}
+
 	BUILD_BUG_ON(sizeof(mode_num) != 1);
 	BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);
 	BUILD_BUG_ON(sizeof(hkdf_info) != 17);
@@ -336,6 +363,14 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_inode_info *ci,
 {
 	int err;
 
+	if (mk->mk_secret.is_hw_wrapped &&
+	    !(ci->ci_policy.v2.flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
+					FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32))) {
+		fscrypt_warn(ci->ci_inode,
+			     "Hardware-wrapped keys are only supported with IV_INO_LBLK policies");
+		return -EINVAL;
+	}
+
 	if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
 		/*
 		 * DIRECT_KEY: instead of deriving per-file encryption keys, the
@@ -362,7 +397,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_inode_info *ci,
 		   FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) {
 		err = fscrypt_setup_iv_ino_lblk_32_key(ci, mk);
 	} else {
-		u8 derived_key[FSCRYPT_MAX_KEY_SIZE];
+		u8 derived_key[FSCRYPT_MAX_RAW_KEY_SIZE];
 
 		err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
 					  HKDF_CONTEXT_PER_FILE_ENC_KEY,
@@ -445,10 +480,6 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci,
 	struct fscrypt_master_key *mk;
 	int err;
 
-	err = fscrypt_select_encryption_impl(ci);
-	if (err)
-		return err;
-
 	err = fscrypt_policy_to_key_spec(&ci->ci_policy, &mk_spec);
 	if (err)
 		return err;
@@ -476,6 +507,10 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci,
 		if (ci->ci_policy.version != FSCRYPT_POLICY_V1)
 			return -ENOKEY;
 
+		err = fscrypt_select_encryption_impl(ci, false);
+		if (err)
+			return err;
+
 		/*
 		 * As a legacy fallback for v1 policies, search for the key in
 		 * the current task's subscribed keyrings too.  Don't move this
@@ -497,9 +532,21 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci,
 		goto out_release_key;
 	}
 
+	err = fscrypt_select_encryption_impl(ci, mk->mk_secret.is_hw_wrapped);
+	if (err)
+		goto out_release_key;
+
 	switch (ci->ci_policy.version) {
 	case FSCRYPT_POLICY_V1:
-		err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw);
+		if (WARN_ON_ONCE(mk->mk_secret.is_hw_wrapped)) {
+			/*
+			 * This should never happen, as adding a v1 policy key
+			 * that is hardware-wrapped isn't allowed.
+			 */
+			err = -EINVAL;
+			goto out_release_key;
+		}
+		err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.bytes);
 		break;
 	case FSCRYPT_POLICY_V2:
 		err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key);
diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index cf3b58ec32cc..b70521c55132 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -118,7 +118,7 @@ find_and_lock_process_key(const char *prefix,
 	payload = (const struct fscrypt_key *)ukp->data;
 
 	if (ukp->datalen != sizeof(struct fscrypt_key) ||
-	    payload->size < 1 || payload->size > FSCRYPT_MAX_KEY_SIZE) {
+	    payload->size < 1 || payload->size > sizeof(payload->raw)) {
 		fscrypt_warn(NULL,
 			     "key with description '%s' has invalid payload",
 			     key->description);
@@ -149,7 +149,7 @@ struct fscrypt_direct_key {
 	const struct fscrypt_mode	*dk_mode;
 	struct fscrypt_prepared_key	dk_key;
 	u8				dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
-	u8				dk_raw[FSCRYPT_MAX_KEY_SIZE];
+	u8				dk_raw[FSCRYPT_MAX_RAW_KEY_SIZE];
 };
 
 static void free_direct_key(struct fscrypt_direct_key *dk)