Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
new file mode 100644
index 0000000..3b6b8cc
--- /dev/null
+++ b/include/linux/fsverity.h
@@ -0,0 +1,211 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * fs-verity: read-only file-based authenticity protection
+ *
+ * This header declares the interface between the fs/verity/ support layer and
+ * filesystems that support fs-verity.
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef _LINUX_FSVERITY_H
+#define _LINUX_FSVERITY_H
+
+#include <linux/fs.h>
+#include <uapi/linux/fsverity.h>
+
+/* Verity operations for filesystems */
+struct fsverity_operations {
+
+ /**
+ * Begin enabling verity on the given file.
+ *
+ * @filp: a readonly file descriptor for the file
+ *
+ * The filesystem must do any needed filesystem-specific preparations
+ * for enabling verity, e.g. evicting inline data. It also must return
+ * -EBUSY if verity is already being enabled on the given file.
+ *
+ * i_rwsem is held for write.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+ int (*begin_enable_verity)(struct file *filp);
+
+ /**
+ * End enabling verity on the given file.
+ *
+ * @filp: a readonly file descriptor for the file
+ * @desc: the verity descriptor to write, or NULL on failure
+ * @desc_size: size of verity descriptor, or 0 on failure
+ * @merkle_tree_size: total bytes the Merkle tree took up
+ *
+ * If desc == NULL, then enabling verity failed and the filesystem only
+ * must do any necessary cleanups. Else, it must also store the given
+ * verity descriptor to a fs-specific location associated with the inode
+ * and do any fs-specific actions needed to mark the inode as a verity
+ * inode, e.g. setting a bit in the on-disk inode. The filesystem is
+ * also responsible for setting the S_VERITY flag in the VFS inode.
+ *
+ * i_rwsem is held for write, but it may have been dropped between
+ * ->begin_enable_verity() and ->end_enable_verity().
+ *
+ * Return: 0 on success, -errno on failure
+ */
+ int (*end_enable_verity)(struct file *filp, const void *desc,
+ size_t desc_size, u64 merkle_tree_size);
+
+ /**
+ * Get the verity descriptor of the given inode.
+ *
+ * @inode: an inode with the S_VERITY flag set
+ * @buf: buffer in which to place the verity descriptor
+ * @bufsize: size of @buf, or 0 to retrieve the size only
+ *
+ * If bufsize == 0, then the size of the verity descriptor is returned.
+ * Otherwise the verity descriptor is written to 'buf' and its actual
+ * size is returned; -ERANGE is returned if it's too large. This may be
+ * called by multiple processes concurrently on the same inode.
+ *
+ * Return: the size on success, -errno on failure
+ */
+ int (*get_verity_descriptor)(struct inode *inode, void *buf,
+ size_t bufsize);
+
+ /**
+ * Read a Merkle tree page of the given inode.
+ *
+ * @inode: the inode
+ * @index: 0-based index of the page within the Merkle tree
+ *
+ * This can be called at any time on an open verity file, as well as
+ * between ->begin_enable_verity() and ->end_enable_verity(). It may be
+ * called by multiple processes concurrently, even with the same page.
+ *
+ * Note that this must retrieve a *page*, not necessarily a *block*.
+ *
+ * Return: the page on success, ERR_PTR() on failure
+ */
+ struct page *(*read_merkle_tree_page)(struct inode *inode,
+ pgoff_t index);
+
+ /**
+ * Write a Merkle tree block to the given inode.
+ *
+ * @inode: the inode for which the Merkle tree is being built
+ * @buf: block to write
+ * @index: 0-based index of the block within the Merkle tree
+ * @log_blocksize: log base 2 of the Merkle tree block size
+ *
+ * This is only called between ->begin_enable_verity() and
+ * ->end_enable_verity().
+ *
+ * Return: 0 on success, -errno on failure
+ */
+ int (*write_merkle_tree_block)(struct inode *inode, const void *buf,
+ u64 index, int log_blocksize);
+};
+
+#ifdef CONFIG_FS_VERITY
+
+static inline struct fsverity_info *fsverity_get_info(const struct inode *inode)
+{
+ /* pairs with the cmpxchg() in fsverity_set_info() */
+ return READ_ONCE(inode->i_verity_info);
+}
+
+/* enable.c */
+
+extern int fsverity_ioctl_enable(struct file *filp, const void __user *arg);
+
+/* measure.c */
+
+extern int fsverity_ioctl_measure(struct file *filp, void __user *arg);
+
+/* open.c */
+
+extern int fsverity_file_open(struct inode *inode, struct file *filp);
+extern int fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr);
+extern void fsverity_cleanup_inode(struct inode *inode);
+
+/* verify.c */
+
+extern bool fsverity_verify_page(struct page *page);
+extern void fsverity_verify_bio(struct bio *bio);
+extern void fsverity_enqueue_verify_work(struct work_struct *work);
+
+#else /* !CONFIG_FS_VERITY */
+
+static inline struct fsverity_info *fsverity_get_info(const struct inode *inode)
+{
+ return NULL;
+}
+
+/* enable.c */
+
+static inline int fsverity_ioctl_enable(struct file *filp,
+ const void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+/* measure.c */
+
+static inline int fsverity_ioctl_measure(struct file *filp, void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+/* open.c */
+
+static inline int fsverity_file_open(struct inode *inode, struct file *filp)
+{
+ return IS_VERITY(inode) ? -EOPNOTSUPP : 0;
+}
+
+static inline int fsverity_prepare_setattr(struct dentry *dentry,
+ struct iattr *attr)
+{
+ return IS_VERITY(d_inode(dentry)) ? -EOPNOTSUPP : 0;
+}
+
+static inline void fsverity_cleanup_inode(struct inode *inode)
+{
+}
+
+/* verify.c */
+
+static inline bool fsverity_verify_page(struct page *page)
+{
+ WARN_ON(1);
+ return false;
+}
+
+static inline void fsverity_verify_bio(struct bio *bio)
+{
+ WARN_ON(1);
+}
+
+static inline void fsverity_enqueue_verify_work(struct work_struct *work)
+{
+ WARN_ON(1);
+}
+
+#endif /* !CONFIG_FS_VERITY */
+
+/**
+ * fsverity_active() - do reads from the inode need to go through fs-verity?
+ *
+ * This checks whether ->i_verity_info has been set.
+ *
+ * Filesystems call this from ->readpages() to check whether the pages need to
+ * be verified or not. Don't use IS_VERITY() for this purpose; it's subject to
+ * a race condition where the file is being read concurrently with
+ * FS_IOC_ENABLE_VERITY completing. (S_VERITY is set before ->i_verity_info.)
+ */
+static inline bool fsverity_active(const struct inode *inode)
+{
+ return fsverity_get_info(inode) != NULL;
+}
+
+#endif /* _LINUX_FSVERITY_H */