[PATCH v2 2/4] generic: add helpers for dumping fs-verity metadata

From: Eric Biggers <ebiggers@kernel.org>
To: fstests@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
	Theodore Ts'o <tytso@mit.edu>,
	Victor Hsieh <victorhsieh@google.com>
Subject: [PATCH v2 2/4] generic: add helpers for dumping fs-verity metadata
Date: Wed, 24 Feb 2021 14:35:35 -0800	[thread overview]
Message-ID: <20210224223537.110491-3-ebiggers@kernel.org> (raw)
In-Reply-To: <20210224223537.110491-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

In common/verity, add helper functions for dumping a file's fs-verity
metadata using the new FS_IOC_READ_VERITY_METADATA ioctl.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 common/verity | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/common/verity b/common/verity
index 9a182240..38eea157 100644
--- a/common/verity
+++ b/common/verity
@@ -120,6 +120,27 @@ _restore_fsverity_signatures()
         fi
 }
 
+# Require userspace and kernel support for 'fsverity dump_metadata'.
+# $1 must be a file with fs-verity enabled.
+_require_fsverity_dump_metadata()
+{
+	local verity_file=$1
+	local tmpfile=$tmp.require_fsverity_dump_metadata
+
+	if _fsv_dump_merkle_tree "$verity_file" 2>"$tmpfile" >/dev/null; then
+		return
+	fi
+	if grep -q "^ERROR: unrecognized command: 'dump_metadata'$" "$tmpfile"
+	then
+		_notrun "Missing 'fsverity dump_metadata' command"
+	fi
+	if grep -q "^ERROR: FS_IOC_READ_VERITY_METADATA failed on '.*': Inappropriate ioctl for device$" "$tmpfile"
+	then
+		_notrun "Kernel doesn't support FS_IOC_READ_VERITY_METADATA"
+	fi
+	_fail "Unexpected output from 'fsverity dump_metadata': $(<"$tmpfile")"
+}
+
 _scratch_mkfs_verity()
 {
 	case $FSTYP in
@@ -157,6 +178,21 @@ _fsv_scratch_begin_subtest()
 	echo -e "\n# $msg"
 }
 
+_fsv_dump_merkle_tree()
+{
+	$FSVERITY_PROG dump_metadata merkle_tree "$@"
+}
+
+_fsv_dump_descriptor()
+{
+	$FSVERITY_PROG dump_metadata descriptor "$@"
+}
+
+_fsv_dump_signature()
+{
+	$FSVERITY_PROG dump_metadata signature "$@"
+}
+
 _fsv_enable()
 {
 	$FSVERITY_PROG enable "$@"
-- 
2.30.1

