Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "A very large number of cleanups and bug fixes --- in particular for
  the ext4 encryption patches, which is a new feature added in the last
  merge window.  Also fix a number of long-standing xfstest failures.
  (Quota writes failing due to ENOSPC, a race between truncate and
  writepage in data=journalled mode that was causing generic/068 to
  fail, and other corner cases.)

  Also add support for FALLOC_FL_INSERT_RANGE, and improve jbd2
  performance eliminating locking when a buffer is modified more than
  once during a transaction (which is very common for allocation
  bitmaps, for example), in which case the state of the journalled
  buffer head doesn't need to change"

[ I renamed "ext4_follow_link()" to "ext4_encrypted_follow_link()" in
  the merge resolution, to make it clear that that function is _only_
  used for encrypted symlinks.  The function doesn't actually work for
  non-encrypted symlinks at all, and they use the generic helpers
                                         - Linus ]

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (52 commits)
  ext4: set lazytime on remount if MS_LAZYTIME is set by mount
  ext4: only call ext4_truncate when size <= isize
  ext4: make online defrag error reporting consistent
  ext4: minor cleanup of ext4_da_reserve_space()
  ext4: don't retry file block mapping on bigalloc fs with non-extent file
  ext4: prevent ext4_quota_write() from failing due to ENOSPC
  ext4: call sync_blockdev() before invalidate_bdev() in put_super()
  jbd2: speedup jbd2_journal_dirty_metadata()
  jbd2: get rid of open coded allocation retry loop
  ext4: improve warning directory handling messages
  jbd2: fix ocfs2 corrupt when updating journal superblock fails
  ext4: mballoc: avoid 20-argument function call
  ext4: wait for existing dio workers in ext4_alloc_file_blocks()
  ext4: recalculate journal credits as inode depth changes
  jbd2: use GFP_NOFS in jbd2_cleanup_journal_tail()
  ext4: use swap() in mext_page_double_lock()
  ext4: use swap() in memswap()
  ext4: fix race between truncate and __ext4_journalled_writepage()
  ext4 crypto: fail the mount if blocksize != pagesize
  ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate
  ...

1 files changed, 123 insertions, 29 deletions

diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
index 52170d0b7c40..442d24e8efc0 100644
--- a/fs/ext4/crypto_key.c
+++ b/fs/ext4/crypto_key.c
@@ -84,14 +84,38 @@ 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_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_encryption_key *crypt_key = &ei->i_encryption_key;
+	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;
@@ -99,31 +123,76 @@ int ext4_generate_encryption_key(struct inode *inode)
 	struct ext4_encryption_context ctx;
 	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);
@@ -138,6 +207,7 @@ int ext4_generate_encryption_key(struct inode *inode)
 		keyring_key = NULL;
 		goto out;
 	}
+	crypt_info->ci_keyring_key = keyring_key;
 	BUG_ON(keyring_key->type != &key_type_logon);
 	ukp = ((struct user_key_payload *)keyring_key->payload.data);
 	if (ukp->datalen != sizeof(struct ext4_encryption_key)) {
@@ -148,19 +218,43 @@ int ext4_generate_encryption_key(struct inode *inode)
 	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);
+	res = ext4_derive_key_aes(ctx.nonce, master_key->raw,
+				  raw_key);
+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);
 }