1 files changed, 145 insertions, 35 deletions

diff --git a/kernel/fs/ext4/crypto_key.c b/kernel/fs/ext4/crypto_key.c
index 52170d0b7..9a16d1e75 100644
--- a/kernel/fs/ext4/crypto_key.c
+++ b/kernel/fs/ext4/crypto_key.c
@@ -30,7 +30,7 @@ static void derive_crypt_complete(struct crypto_async_request *req, int rc)
 
 /**
  * ext4_derive_key_aes() - Derive a key using AES-128-ECB
- * @deriving_key: Encryption key used for derivatio.
+ * @deriving_key: Encryption key used for derivation.
  * @source_key:   Source key to which to apply derivation.
  * @derived_key:  Derived key.
  *
@@ -71,7 +71,6 @@ static int ext4_derive_key_aes(char deriving_key[EXT4_AES_128_ECB_KEY_SIZE],
 				     EXT4_AES_256_XTS_KEY_SIZE, NULL);
 	res = crypto_ablkcipher_encrypt(req);
 	if (res == -EINPROGRESS || res == -EBUSY) {
-		BUG_ON(req->base.data != &ecr);
 		wait_for_completion(&ecr.completion);
 		res = ecr.res;
 	}
@@ -84,46 +83,115 @@ out:
 	return res;
 }
 
-/**
- * ext4_generate_encryption_key() - generates an encryption key
- * @inode: The inode to generate the encryption key for.
- */
-int ext4_generate_encryption_key(struct inode *inode)
+void ext4_free_crypt_info(struct ext4_crypt_info *ci)
+{
+	if (!ci)
+		return;
+
+	if (ci->ci_keyring_key)
+		key_put(ci->ci_keyring_key);
+	crypto_free_ablkcipher(ci->ci_ctfm);
+	kmem_cache_free(ext4_crypt_info_cachep, ci);
+}
+
+void ext4_free_encryption_info(struct inode *inode,
+			       struct ext4_crypt_info *ci)
 {
 	struct ext4_inode_info *ei = EXT4_I(inode);
-	struct ext4_encryption_key *crypt_key = &ei->i_encryption_key;
+	struct ext4_crypt_info *prev;
+
+	if (ci == NULL)
+		ci = ACCESS_ONCE(ei->i_crypt_info);
+	if (ci == NULL)
+		return;
+	prev = cmpxchg(&ei->i_crypt_info, ci, NULL);
+	if (prev != ci)
+		return;
+
+	ext4_free_crypt_info(ci);
+}
+
+int _ext4_get_encryption_info(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_crypt_info *crypt_info;
 	char full_key_descriptor[EXT4_KEY_DESC_PREFIX_SIZE +
 				 (EXT4_KEY_DESCRIPTOR_SIZE * 2) + 1];
 	struct key *keyring_key = NULL;
 	struct ext4_encryption_key *master_key;
 	struct ext4_encryption_context ctx;
-	struct user_key_payload *ukp;
+	const struct user_key_payload *ukp;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-	int res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
-				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
-				 &ctx, sizeof(ctx));
+	struct crypto_ablkcipher *ctfm;
+	const char *cipher_str;
+	char raw_key[EXT4_MAX_KEY_SIZE];
+	char mode;
+	int res;
 
-	if (res != sizeof(ctx)) {
-		if (res > 0)
-			res = -EINVAL;
-		goto out;
+	if (!ext4_read_workqueue) {
+		res = ext4_init_crypto();
+		if (res)
+			return res;
 	}
+
+retry:
+	crypt_info = ACCESS_ONCE(ei->i_crypt_info);
+	if (crypt_info) {
+		if (!crypt_info->ci_keyring_key ||
+		    key_validate(crypt_info->ci_keyring_key) == 0)
+			return 0;
+		ext4_free_encryption_info(inode, crypt_info);
+		goto retry;
+	}
+
+	res = ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
+				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+				 &ctx, sizeof(ctx));
+	if (res < 0) {
+		if (!DUMMY_ENCRYPTION_ENABLED(sbi))
+			return res;
+		ctx.contents_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
+		ctx.filenames_encryption_mode =
+			EXT4_ENCRYPTION_MODE_AES_256_CTS;
+		ctx.flags = 0;
+	} else if (res != sizeof(ctx))
+		return -EINVAL;
 	res = 0;
 
-	ei->i_crypt_policy_flags = ctx.flags;
+	crypt_info = kmem_cache_alloc(ext4_crypt_info_cachep, GFP_KERNEL);
+	if (!crypt_info)
+		return -ENOMEM;
+
+	crypt_info->ci_flags = ctx.flags;
+	crypt_info->ci_data_mode = ctx.contents_encryption_mode;
+	crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
+	crypt_info->ci_ctfm = NULL;
+	crypt_info->ci_keyring_key = NULL;
+	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
+	       sizeof(crypt_info->ci_master_key));
 	if (S_ISREG(inode->i_mode))
-		crypt_key->mode = ctx.contents_encryption_mode;
+		mode = crypt_info->ci_data_mode;
 	else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
-		crypt_key->mode = ctx.filenames_encryption_mode;
-	else {
-		printk(KERN_ERR "ext4 crypto: Unsupported inode type.\n");
+		mode = crypt_info->ci_filename_mode;
+	else
 		BUG();
+	switch (mode) {
+	case EXT4_ENCRYPTION_MODE_AES_256_XTS:
+		cipher_str = "xts(aes)";
+		break;
+	case EXT4_ENCRYPTION_MODE_AES_256_CTS:
+		cipher_str = "cts(cbc(aes))";
+		break;
+	default:
+		printk_once(KERN_WARNING
+			    "ext4: unsupported key mode %d (ino %u)\n",
+			    mode, (unsigned) inode->i_ino);
+		res = -ENOKEY;
+		goto out;
 	}
-	crypt_key->size = ext4_encryption_key_size(crypt_key->mode);
-	BUG_ON(!crypt_key->size);
 	if (DUMMY_ENCRYPTION_ENABLED(sbi)) {
-		memset(crypt_key->raw, 0x42, EXT4_AES_256_XTS_KEY_SIZE);
-		goto out;
+		memset(raw_key, 0x42, EXT4_AES_256_XTS_KEY_SIZE);
+		goto got_key;
 	}
 	memcpy(full_key_descriptor, EXT4_KEY_DESC_PREFIX,
 	       EXT4_KEY_DESC_PREFIX_SIZE);
@@ -138,29 +206,71 @@ int ext4_generate_encryption_key(struct inode *inode)
 		keyring_key = NULL;
 		goto out;
 	}
-	BUG_ON(keyring_key->type != &key_type_logon);
-	ukp = ((struct user_key_payload *)keyring_key->payload.data);
+	crypt_info->ci_keyring_key = keyring_key;
+	if (keyring_key->type != &key_type_logon) {
+		printk_once(KERN_WARNING
+			    "ext4: key type must be logon\n");
+		res = -ENOKEY;
+		goto out;
+	}
+	down_read(&keyring_key->sem);
+	ukp = user_key_payload(keyring_key);
 	if (ukp->datalen != sizeof(struct ext4_encryption_key)) {
 		res = -EINVAL;
+		up_read(&keyring_key->sem);
 		goto out;
 	}
 	master_key = (struct ext4_encryption_key *)ukp->data;
 	BUILD_BUG_ON(EXT4_AES_128_ECB_KEY_SIZE !=
 		     EXT4_KEY_DERIVATION_NONCE_SIZE);
-	BUG_ON(master_key->size != EXT4_AES_256_XTS_KEY_SIZE);
-	res = ext4_derive_key_aes(ctx.nonce, master_key->raw, crypt_key->raw);
+	if (master_key->size != EXT4_AES_256_XTS_KEY_SIZE) {
+		printk_once(KERN_WARNING
+			    "ext4: key size incorrect: %d\n",
+			    master_key->size);
+		res = -ENOKEY;
+		up_read(&keyring_key->sem);
+		goto out;
+	}
+	res = ext4_derive_key_aes(ctx.nonce, master_key->raw,
+				  raw_key);
+	up_read(&keyring_key->sem);
+	if (res)
+		goto out;
+got_key:
+	ctfm = crypto_alloc_ablkcipher(cipher_str, 0, 0);
+	if (!ctfm || IS_ERR(ctfm)) {
+		res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
+		printk(KERN_DEBUG
+		       "%s: error %d (inode %u) allocating crypto tfm\n",
+		       __func__, res, (unsigned) inode->i_ino);
+		goto out;
+	}
+	crypt_info->ci_ctfm = ctfm;
+	crypto_ablkcipher_clear_flags(ctfm, ~0);
+	crypto_tfm_set_flags(crypto_ablkcipher_tfm(ctfm),
+			     CRYPTO_TFM_REQ_WEAK_KEY);
+	res = crypto_ablkcipher_setkey(ctfm, raw_key,
+				       ext4_encryption_key_size(mode));
+	if (res)
+		goto out;
+	memzero_explicit(raw_key, sizeof(raw_key));
+	if (cmpxchg(&ei->i_crypt_info, NULL, crypt_info) != NULL) {
+		ext4_free_crypt_info(crypt_info);
+		goto retry;
+	}
+	return 0;
+
 out:
-	if (keyring_key)
-		key_put(keyring_key);
-	if (res < 0)
-		crypt_key->mode = EXT4_ENCRYPTION_MODE_INVALID;
+	if (res == -ENOKEY)
+		res = 0;
+	ext4_free_crypt_info(crypt_info);
+	memzero_explicit(raw_key, sizeof(raw_key));
 	return res;
 }
 
 int ext4_has_encryption_key(struct inode *inode)
 {
 	struct ext4_inode_info *ei = EXT4_I(inode);
-	struct ext4_encryption_key *crypt_key = &ei->i_encryption_key;
 
-	return (crypt_key->mode != EXT4_ENCRYPTION_MODE_INVALID);
+	return (ei->i_crypt_info != NULL);
 }