diff mbox series

[v1,04/17] btrfs: start using fscrypt hooks

Message ID a6677d23527af7ed3195a1c5cb90c29c481d70d2.1687988380.git.sweettea-kernel@dorminy.me (mailing list archive)
State New, archived
Headers show
Series btrfs: add encryption feature | expand

Commit Message

Sweet Tea Dorminy June 29, 2023, 12:35 a.m. UTC
From: Omar Sandoval <osandov@osandov.com>

In order to appropriately encrypt, create, open, rename, and various
symlink operations must call fscrypt hooks. These determine whether the
inode should be encrypted and do other preparatory actions. The
superblock must have fscrypt operations registered, so implement the
minimal set also, and introduce the new fscrypt.[ch] files to hold the
fscrypt-specific functionality. Also add the key prefix for fscrypt v1
keys.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 fs/btrfs/Makefile      |  1 +
 fs/btrfs/btrfs_inode.h |  1 +
 fs/btrfs/file.c        |  3 ++
 fs/btrfs/fscrypt.c     |  8 ++++
 fs/btrfs/fscrypt.h     | 10 +++++
 fs/btrfs/inode.c       | 87 +++++++++++++++++++++++++++++++++++-------
 fs/btrfs/super.c       |  2 +
 7 files changed, 99 insertions(+), 13 deletions(-)
 create mode 100644 fs/btrfs/fscrypt.c
 create mode 100644 fs/btrfs/fscrypt.h
diff mbox series

Patch

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 90d53209755b..90d30b1e044a 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -40,6 +40,7 @@  btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
 btrfs-$(CONFIG_BTRFS_FS_REF_VERIFY) += ref-verify.o
 btrfs-$(CONFIG_BLK_DEV_ZONED) += zoned.o
 btrfs-$(CONFIG_FS_VERITY) += verity.o
+btrfs-$(CONFIG_FS_ENCRYPTION) += fscrypt.o
 
 btrfs-$(CONFIG_BTRFS_FS_RUN_SANITY_TESTS) += tests/free-space-tests.o \
 	tests/extent-buffer-tests.o tests/btrfs-tests.o \
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index d47a927b3504..ec4a06a78aff 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -448,6 +448,7 @@  struct btrfs_new_inode_args {
 	struct posix_acl *default_acl;
 	struct posix_acl *acl;
 	struct fscrypt_name fname;
+	bool encrypt;
 };
 
 int btrfs_new_inode_prepare(struct btrfs_new_inode_args *args,
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 354962a7dd72..0de95c8375a1 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3702,6 +3702,9 @@  static int btrfs_file_open(struct inode *inode, struct file *filp)
 
 	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC |
 		        FMODE_CAN_ODIRECT;
+	ret = fscrypt_file_open(inode, filp);
+	if (ret)
+		return ret;
 
 	ret = fsverity_file_open(inode, filp);
 	if (ret)
diff --git a/fs/btrfs/fscrypt.c b/fs/btrfs/fscrypt.c
new file mode 100644
index 000000000000..3a53dc59c1e4
--- /dev/null
+++ b/fs/btrfs/fscrypt.c
@@ -0,0 +1,8 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include "ctree.h"
+#include "fscrypt.h"
+
+const struct fscrypt_operations btrfs_fscrypt_ops = {
+	.key_prefix = "btrfs:"
+};
diff --git a/fs/btrfs/fscrypt.h b/fs/btrfs/fscrypt.h
new file mode 100644
index 000000000000..7f4e6888bd43
--- /dev/null
+++ b/fs/btrfs/fscrypt.h
@@ -0,0 +1,10 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_FSCRYPT_H
+#define BTRFS_FSCRYPT_H
+
+#include <linux/fscrypt.h>
+
+extern const struct fscrypt_operations btrfs_fscrypt_ops;
+
+#endif /* BTRFS_FSCRYPT_H */
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 48eadc4f187f..5ce167cfa1dc 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5337,6 +5337,7 @@  void btrfs_evict_inode(struct inode *inode)
 	trace_btrfs_inode_evict(inode);
 
 	if (!root) {
+		fscrypt_put_encryption_info(inode);
 		fsverity_cleanup_inode(inode);
 		clear_inode(inode);
 		return;
@@ -5440,6 +5441,7 @@  void btrfs_evict_inode(struct inode *inode)
 	 * to retry these periodically in the future.
 	 */
 	btrfs_remove_delayed_node(BTRFS_I(inode));
+	fscrypt_put_encryption_info(inode);
 	fsverity_cleanup_inode(inode);
 	clear_inode(inode);
 }
@@ -6190,6 +6192,10 @@  int btrfs_new_inode_prepare(struct btrfs_new_inode_args *args,
 		return ret;
 	}
 
+	ret = fscrypt_prepare_new_inode(dir, inode, &args->encrypt);
+	if (ret)
+		return ret;
+
 	/* 1 to add inode item */
 	*trans_num_items = 1;
 	/* 1 to add compression property */
@@ -6666,9 +6672,13 @@  static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	if (inode->i_nlink >= BTRFS_LINK_MAX)
 		return -EMLINK;
 
+	err = fscrypt_prepare_link(old_dentry, dir, dentry);
+	if (err)
+		return err;
+
 	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &fname);
 	if (err)
-		goto fail;
+		return err;
 
 	err = btrfs_set_inode_index(BTRFS_I(dir), &index);
 	if (err)
@@ -8612,6 +8622,7 @@  void btrfs_test_destroy_inode(struct inode *inode)
 
 void btrfs_free_inode(struct inode *inode)
 {
+	fscrypt_free_inode(inode);
 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
@@ -8682,8 +8693,7 @@  int btrfs_drop_inode(struct inode *inode)
 	/* the snap/subvol tree is on deleting */
 	if (btrfs_root_refs(&root->root_item) == 0)
 		return 1;
-	else
-		return generic_drop_inode(inode);
+	return generic_drop_inode(inode) || fscrypt_drop_inode(inode);
 }
 
 static void init_once(void *foo)
@@ -9274,6 +9284,11 @@  static int btrfs_rename2(struct mnt_idmap *idmap, struct inode *old_dir,
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
 		return -EINVAL;
 
+	ret = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
+				     flags);
+	if (ret)
+		return ret;
+
 	if (flags & RENAME_EXCHANGE)
 		ret = btrfs_rename_exchange(old_dir, old_dentry, new_dir,
 					    new_dentry);
@@ -9493,15 +9508,22 @@  static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	};
 	unsigned int trans_num_items;
 	int err;
-	int name_len;
 	int datasize;
 	unsigned long ptr;
 	struct btrfs_file_extent_item *ei;
 	struct extent_buffer *leaf;
+	struct fscrypt_str disk_link;
+	u32 name_len = strlen(symname);
 
-	name_len = strlen(symname);
-	if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
-		return -ENAMETOOLONG;
+	/*
+	 * fscrypt sets disk_link.len to be len + 1, including a NUL terminator, but we
+	 * don't store that '\0' character.
+	 */
+	err = fscrypt_prepare_symlink(dir, symname, name_len,
+				      BTRFS_MAX_INLINE_DATA_SIZE(fs_info) + 1,
+				      &disk_link);
+	if (err)
+		return err;
 
 	inode = new_inode(dir->i_sb);
 	if (!inode)
@@ -9510,8 +9532,8 @@  static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	inode->i_op = &btrfs_symlink_inode_operations;
 	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &btrfs_aops;
-	btrfs_i_size_write(BTRFS_I(inode), name_len);
-	inode_set_bytes(inode, name_len);
+	btrfs_i_size_write(BTRFS_I(inode), disk_link.len - 1);
+	inode_set_bytes(inode, disk_link.len - 1);
 
 	new_inode_args.inode = inode;
 	err = btrfs_new_inode_prepare(&new_inode_args, &trans_num_items);
@@ -9538,10 +9560,23 @@  static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 		inode = NULL;
 		goto out;
 	}
+
+	if (IS_ENCRYPTED(inode)) {
+		err = fscrypt_encrypt_symlink(inode, symname, name_len,
+					      &disk_link);
+		if (err) {
+			btrfs_abort_transaction(trans, err);
+			btrfs_free_path(path);
+			discard_new_inode(inode);
+			inode = NULL;
+			goto out;
+		}
+	}
+
 	key.objectid = btrfs_ino(BTRFS_I(inode));
 	key.offset = 0;
 	key.type = BTRFS_EXTENT_DATA_KEY;
-	datasize = btrfs_file_extent_calc_inline_size(name_len);
+	datasize = btrfs_file_extent_calc_inline_size(disk_link.len - 1);
 	err = btrfs_insert_empty_item(trans, root, path, &key,
 				      datasize);
 	if (err) {
@@ -9560,10 +9595,10 @@  static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	btrfs_set_file_extent_encryption(leaf, ei, 0);
 	btrfs_set_file_extent_compression(leaf, ei, 0);
 	btrfs_set_file_extent_other_encoding(leaf, ei, 0);
-	btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
+	btrfs_set_file_extent_ram_bytes(leaf, ei, disk_link.len - 1);
 
 	ptr = btrfs_file_extent_inline_start(ei);
-	write_extent_buffer(leaf, symname, ptr, name_len);
+	write_extent_buffer(leaf, disk_link.name, ptr, disk_link.len - 1);
 	btrfs_mark_buffer_dirty(leaf);
 	btrfs_free_path(path);
 
@@ -9580,6 +9615,29 @@  static int btrfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	return err;
 }
 
+static const char *btrfs_get_link(struct dentry *dentry, struct inode *inode,
+				  struct delayed_call *done)
+{
+	struct page *cpage;
+	const char *paddr;
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+
+	if (!IS_ENCRYPTED(inode))
+		return page_get_link(dentry, inode, done);
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	cpage = read_mapping_page(inode->i_mapping, 0, NULL);
+	if (IS_ERR(cpage))
+		return ERR_CAST(cpage);
+
+	paddr = fscrypt_get_symlink(inode, page_address(cpage),
+				    BTRFS_MAX_INLINE_DATA_SIZE(fs_info), done);
+	put_page(cpage);
+	return paddr;
+}
+
 static struct btrfs_trans_handle *insert_prealloc_file_extent(
 				       struct btrfs_trans_handle *trans_in,
 				       struct btrfs_inode *inode,
@@ -11058,7 +11116,7 @@  static const struct inode_operations btrfs_special_inode_operations = {
 	.update_time	= btrfs_update_time,
 };
 static const struct inode_operations btrfs_symlink_inode_operations = {
-	.get_link	= page_get_link,
+	.get_link	= btrfs_get_link,
 	.getattr	= btrfs_getattr,
 	.setattr	= btrfs_setattr,
 	.permission	= btrfs_permission,
@@ -11068,4 +11126,7 @@  static const struct inode_operations btrfs_symlink_inode_operations = {
 
 const struct dentry_operations btrfs_dentry_operations = {
 	.d_delete	= btrfs_dentry_delete,
+#ifdef CONFIG_FS_ENCRYPTION
+	.d_revalidate	= fscrypt_d_revalidate,
+#endif
 };
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 8b1c1225245e..d0df46370c5d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -48,6 +48,7 @@ 
 #include "tests/btrfs-tests.h"
 #include "block-group.h"
 #include "discard.h"
+#include "fscrypt.h"
 #include "qgroup.h"
 #include "raid56.h"
 #include "fs.h"
@@ -1140,6 +1141,7 @@  static int btrfs_fill_super(struct super_block *sb,
 	sb->s_vop = &btrfs_verityops;
 #endif
 	sb->s_xattr = btrfs_xattr_handlers;
+	fscrypt_set_ops(sb, &btrfs_fscrypt_ops);
 	sb->s_time_gran = 1;
 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 	sb->s_flags |= SB_POSIXACL;