From 0185defb7f2e2a76b2ec5fb77cec2f1aeb412682 Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Tue, 13 Dec 2016 13:52:05 +0100
Subject: [PATCH] Check for data device and hash device area overlap in
 veritysetup.

Thanks Michal Virgovic for tests.
---
 lib/internal.h           |  1 +
 lib/setup.c              |  6 ++++++
 lib/utils_device.c       | 15 +++++++++++++++
 tests/verity-compat-test | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/lib/internal.h b/lib/internal.h
index 521398a9..ada1c5c6 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -76,6 +76,7 @@ int device_read_ahead(struct device *device, uint32_t *read_ahead);
 int device_size(struct device *device, uint64_t *size);
 int device_open(struct device *device, int flags);
 void device_disable_direct_io(struct device *device);
+int device_is_identical(struct device *device1, struct device *device2);
 
 
 enum devcheck { DEV_OK = 0, DEV_EXCL = 1, DEV_SHARED = 2 };
diff --git a/lib/setup.c b/lib/setup.c
index 4b303601..84da6181 100644
--- a/lib/setup.c
+++ b/lib/setup.c
@@ -1188,6 +1188,12 @@ static int _crypt_format_verity(struct crypt_device *cd,
 	} else
 		cd->u.verity.hdr.data_size = params->data_size;
 
+	if (device_is_identical(crypt_metadata_device(cd), crypt_data_device(cd)) &&
+	   (cd->u.verity.hdr.data_size * params->data_block_size) > params->hash_area_offset) {
+		log_err(cd, _("Data area overlaps with hash area.\n"));
+		return -EINVAL;
+	}
+
 	hash_size = crypt_hash_size(params->hash_name);
 	if (hash_size <= 0) {
 		log_err(cd, _("Hash algorithm %s not supported.\n"),
diff --git a/lib/utils_device.c b/lib/utils_device.c
index 8c4d4349..b3ea8ac3 100644
--- a/lib/utils_device.c
+++ b/lib/utils_device.c
@@ -535,3 +535,18 @@ void device_disable_direct_io(struct device *device)
 {
 	device->o_direct = 0;
 }
+
+int device_is_identical(struct device *device1, struct device *device2)
+{
+	if (device1 == device2)
+		return 1;
+
+	if (!device1 || !device2 || !device_path(device1) || !device_path(device2))
+		return 0;
+
+	/* This should be better check - major/minor for block device etc */
+	if (!strcmp(device_path(device1), device_path(device2)))
+		return 1;
+
+	return 0;
+}
diff --git a/tests/verity-compat-test b/tests/verity-compat-test
index cb90edaf..a6264f6d 100755
--- a/tests/verity-compat-test
+++ b/tests/verity-compat-test
@@ -171,6 +171,31 @@ function valgrind_run()
 	INFOSTRING="$(basename ${BASH_SOURCE[1]})-line-${BASH_LINENO[0]}" ./valg.sh ${VERITYSETUP} "$@"
 }
 
+function checkOffsetBug() # $1 size, $2 hash-offset, $3 data-blocks
+{
+	echo -n "Size :: $1 B | Hash-offset :: $2 blocks | Data-blocks :: $3 "
+	dd if=/dev/zero of=$IMG bs=1 count=0 seek=$1 >/dev/null 2>&1
+	$VERITYSETUP --data-blocks=$3 --hash-offset=$2 format $IMG $IMG >/dev/null 2>&1 || fail "Test [hash-offset greater than 2G] failed"
+	echo "[OK]"
+	remove_mapping
+}
+function checkOverlapBug() # $1 size, $2 hash-offset, $3 data-blocks
+{
+	echo -n "Size :: $1 B | Hash-offset :: $2 blocks | "
+
+	dd if=/dev/zero of=$IMG bs=1 count=0 seek=$1 >/dev/null 2>&1
+	if [ -z $3 ] ; then
+	  # veritysetup must fail
+	  $VERITYSETUP --hash-offset=$2 format $IMG $IMG >/dev/null 2>&1 && fail "Test [overlap with option \"--data-blocks\" not entered] failed"
+	else
+	  $VERITYSETUP --data-blocks=$3 --hash-offset=$2 format $IMG $IMG >/dev/null 2>&1 || fail "Test [overlap with option \"--data-blocks\" entered] failed"
+	  RET=$?
+	  [ "$3" -gt "$(($2 / 4096))" ] && [ "$RET" -eq "0" ] && fail "Test [overlap - hash-offset in data area] failed"
+	fi
+	echo "[OK]"
+	remove_mapping
+}
+
 [ $(id -u) != 0 ] && skip "WARNING: You must be root to run this test, test skipped."
 [ ! -x "$VERITYSETUP" ] && skip "Cannot find $VERITYSETUP, test skipped."
 
@@ -208,6 +233,7 @@ check_root_hash 4096 ef29c902d87350f1da4bfa536e16cebc162a909bf89abe448b81ec500d4
 check_root_hash 1024 d0e9163ca8844aaa2e88fe5265a8c5d9ee494a99 $SALT 1 sha1 8388608
 check_root_hash 1024 73509e8e868be6b8ac939817a98a3d35121413b2 dadada 1 sha1 8388608
 
+
 if check_version ; then
 	echo "Verity data corruption options test."
 	SALT=e48da609055204e89ae53b655ca2216dd983cf3cb829f34f63a297d106d53e2d
@@ -219,5 +245,13 @@ if check_version ; then
 	check_option 512 $HASH $SALT 1 sha256 "--ignore-corruption --ignore-zero-blocks" "ignore_corruption"
 fi
 
+echo "Veritysetup [hash-offset bigger than 2G works] "
+checkOffsetBug 3000000000 2499997696 256
+checkOffsetBug 10000000000 8000000000 128
+
+echo "Veritysetup [overlap-detection] "
+checkOverlapBug 2097152 1433600
+checkOverlapBug 2097152 1433600 350
+
 remove_mapping
 exit 0