Merge tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt

Pull fs-verity support from Eric Biggers:
 "fs-verity is a filesystem feature that provides Merkle tree based
  hashing (similar to dm-verity) for individual readonly files, mainly
  for the purpose of efficient authenticity verification.

  This pull request includes:

   (a) The fs/verity/ support layer and documentation.

   (b) fs-verity support for ext4 and f2fs.

  Compared to the original fs-verity patchset from last year, the UAPI
  to enable fs-verity on a file has been greatly simplified. Lots of
  other things were cleaned up too.

  fs-verity is planned to be used by two different projects on Android;
  most of the userspace code is in place already. Another userspace tool
  ("fsverity-utils"), and xfstests, are also available. e2fsprogs and
  f2fs-tools already have fs-verity support. Other people have shown
  interest in using fs-verity too.

  I've tested this on ext4 and f2fs with xfstests, both the existing
  tests and the new fs-verity tests. This has also been in linux-next
  since July 30 with no reported issues except a couple minor ones I
  found myself and folded in fixes for.

  Ted and I will be co-maintaining fs-verity"

* tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  f2fs: add fs-verity support
  ext4: update on-disk format documentation for fs-verity
  ext4: add fs-verity read support
  ext4: add basic fs-verity support
  fs-verity: support builtin file signatures
  fs-verity: add SHA-512 support
  fs-verity: implement FS_IOC_MEASURE_VERITY ioctl
  fs-verity: implement FS_IOC_ENABLE_VERITY ioctl
  fs-verity: add data verification hooks for ->readpages()
  fs-verity: add the hook for file ->setattr()
  fs-verity: add the hook for file ->open()
  fs-verity: add inode and superblock fields
  fs-verity: add Kconfig and the helper functions for hashing
  fs: uapi: define verity bit for FS_IOC_GETFLAGS
  fs-verity: add UAPI header
  fs-verity: add MAINTAINERS file entry
  fs-verity: add a documentation file

1 files changed, 40 insertions, 15 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 006b7a2070bf..d0dc0e3463db 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1340,6 +1340,9 @@ retry_journal:
 	}
 
 	if (ret) {
+		bool extended = (pos + len > inode->i_size) &&
+				!ext4_verity_in_progress(inode);
+
 		unlock_page(page);
 		/*
 		 * __block_write_begin may have instantiated a few blocks
@@ -1349,11 +1352,11 @@ retry_journal:
 		 * Add inode to orphan list in case we crash before
 		 * truncate finishes
 		 */
-		if (pos + len > inode->i_size && ext4_can_truncate(inode))
+		if (extended && ext4_can_truncate(inode))
 			ext4_orphan_add(handle, inode);
 
 		ext4_journal_stop(handle);
-		if (pos + len > inode->i_size) {
+		if (extended) {
 			ext4_truncate_failed_write(inode);
 			/*
 			 * If truncate failed early the inode might
@@ -1406,6 +1409,7 @@ static int ext4_write_end(struct file *file,
 	int ret = 0, ret2;
 	int i_size_changed = 0;
 	int inline_data = ext4_has_inline_data(inode);
+	bool verity = ext4_verity_in_progress(inode);
 
 	trace_ext4_write_end(inode, pos, len, copied);
 	if (inline_data) {
@@ -1423,12 +1427,16 @@ static int ext4_write_end(struct file *file,
 	/*
 	 * it's important to update i_size while still holding page lock:
 	 * page writeout could otherwise come in and zero beyond i_size.
+	 *
+	 * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
+	 * blocks are being written past EOF, so skip the i_size update.
 	 */
-	i_size_changed = ext4_update_inode_size(inode, pos + copied);
+	if (!verity)
+		i_size_changed = ext4_update_inode_size(inode, pos + copied);
 	unlock_page(page);
 	put_page(page);
 
-	if (old_size < pos)
+	if (old_size < pos && !verity)
 		pagecache_isize_extended(inode, old_size, pos);
 	/*
 	 * Don't mark the inode dirty under page lock. First, it unnecessarily
@@ -1439,7 +1447,7 @@ static int ext4_write_end(struct file *file,
 	if (i_size_changed || inline_data)
 		ext4_mark_inode_dirty(handle, inode);
 
-	if (pos + len > inode->i_size && ext4_can_truncate(inode))
+	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
 		/* if we have allocated more blocks and copied
 		 * less. We will have blocks allocated outside
 		 * inode->i_size. So truncate them
@@ -1450,7 +1458,7 @@ errout:
 	if (!ret)
 		ret = ret2;
 
-	if (pos + len > inode->i_size) {
+	if (pos + len > inode->i_size && !verity) {
 		ext4_truncate_failed_write(inode);
 		/*
 		 * If truncate failed early the inode might still be
@@ -1511,6 +1519,7 @@ static int ext4_journalled_write_end(struct file *file,
 	unsigned from, to;
 	int size_changed = 0;
 	int inline_data = ext4_has_inline_data(inode);
+	bool verity = ext4_verity_in_progress(inode);
 
 	trace_ext4_journalled_write_end(inode, pos, len, copied);
 	from = pos & (PAGE_SIZE - 1);
@@ -1540,13 +1549,14 @@ static int ext4_journalled_write_end(struct file *file,
 		if (!partial)
 			SetPageUptodate(page);
 	}
-	size_changed = ext4_update_inode_size(inode, pos + copied);
+	if (!verity)
+		size_changed = ext4_update_inode_size(inode, pos + copied);
 	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
 	unlock_page(page);
 	put_page(page);
 
-	if (old_size < pos)
+	if (old_size < pos && !verity)
 		pagecache_isize_extended(inode, old_size, pos);
 
 	if (size_changed || inline_data) {
@@ -1555,7 +1565,7 @@ static int ext4_journalled_write_end(struct file *file,
 			ret = ret2;
 	}
 
-	if (pos + len > inode->i_size && ext4_can_truncate(inode))
+	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
 		/* if we have allocated more blocks and copied
 		 * less. We will have blocks allocated outside
 		 * inode->i_size. So truncate them
@@ -1566,7 +1576,7 @@ errout:
 	ret2 = ext4_journal_stop(handle);
 	if (!ret)
 		ret = ret2;
-	if (pos + len > inode->i_size) {
+	if (pos + len > inode->i_size && !verity) {
 		ext4_truncate_failed_write(inode);
 		/*
 		 * If truncate failed early the inode might still be
@@ -2162,7 +2172,8 @@ static int ext4_writepage(struct page *page,
 
 	trace_ext4_writepage(page);
 	size = i_size_read(inode);
-	if (page->index == size >> PAGE_SHIFT)
+	if (page->index == size >> PAGE_SHIFT &&
+	    !ext4_verity_in_progress(inode))
 		len = size & ~PAGE_MASK;
 	else
 		len = PAGE_SIZE;
@@ -2246,7 +2257,8 @@ static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
 	 * after page tables are updated.
 	 */
 	size = i_size_read(mpd->inode);
-	if (page->index == size >> PAGE_SHIFT)
+	if (page->index == size >> PAGE_SHIFT &&
+	    !ext4_verity_in_progress(mpd->inode))
 		len = size & ~PAGE_MASK;
 	else
 		len = PAGE_SIZE;
@@ -2345,6 +2357,9 @@ static int mpage_process_page_bufs(struct mpage_da_data *mpd,
 	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
 							>> inode->i_blkbits;
 
+	if (ext4_verity_in_progress(inode))
+		blocks = EXT_MAX_BLOCKS;
+
 	do {
 		BUG_ON(buffer_locked(bh));
 
@@ -3061,8 +3076,8 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
 
 	index = pos >> PAGE_SHIFT;
 
-	if (ext4_nonda_switch(inode->i_sb) ||
-	    S_ISLNK(inode->i_mode)) {
+	if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) ||
+	    ext4_verity_in_progress(inode)) {
 		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
 		return ext4_write_begin(file, mapping, pos,
 					len, flags, pagep, fsdata);
@@ -3897,6 +3912,8 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
 		return 0;
 #endif
+	if (fsverity_active(inode))
+		return 0;
 
 	/*
 	 * If we are doing data journalling we don't support O_DIRECT
@@ -4736,6 +4753,8 @@ static bool ext4_should_use_dax(struct inode *inode)
 		return false;
 	if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
 		return false;
+	if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
+		return false;
 	return true;
 }
 
@@ -4760,9 +4779,11 @@ void ext4_set_inode_flags(struct inode *inode)
 		new_fl |= S_ENCRYPTED;
 	if (flags & EXT4_CASEFOLD_FL)
 		new_fl |= S_CASEFOLD;
+	if (flags & EXT4_VERITY_FL)
+		new_fl |= S_VERITY;
 	inode_set_flags(inode, new_fl,
 			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
-			S_ENCRYPTED|S_CASEFOLD);
+			S_ENCRYPTED|S_CASEFOLD|S_VERITY);
 }
 
 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
@@ -5552,6 +5573,10 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 	if (error)
 		return error;
 
+	error = fsverity_prepare_setattr(dentry, attr);
+	if (error)
+		return error;
+
 	if (is_quota_modification(inode, attr)) {
 		error = dquot_initialize(inode);
 		if (error)