From cdb91409674cfb5d94a374b1e3b2bf1869ecfec7 Mon Sep 17 00:00:00 2001
From: Karel Zak
Date: Wed, 17 Jul 2019 12:35:45 +0200
Subject: libblkid: do not interpret NTFS as MBR

 # mkntfs -Q -F /dev/sdc

old version:
 # ./blkid -p /dev/sdc
 /dev/sdc: UUID="0E9E8C5F2F718479" TYPE="ntfs" USAGE="filesystem" PTTYPE="dos"

new version:
 # ./blkid -p /dev/sdc
 /dev/sdc: UUID="0E9E8C5F2F718479" TYPE="ntfs" USAGE="filesystem"

Reported-by: Mike Fleetwood <mike.fleetwood@googlemail.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 libblkid/src/partitions/dos.c          |  7 +++++++
 libblkid/src/superblocks/ntfs.c        | 24 +++++++++++++++++++++++-
 libblkid/src/superblocks/superblocks.h |  1 +
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/libblkid/src/partitions/dos.c b/libblkid/src/partitions/dos.c
index 6c1b519f7..f8b0ee50d 100644
--- a/libblkid/src/partitions/dos.c
+++ b/libblkid/src/partitions/dos.c
@@ -14,6 +14,7 @@
 #include <stdint.h>
 
 #include "partitions.h"
+#include "superblocks/superblocks.h"
 #include "aix.h"
 
 /* see superblocks/vfat.c */
@@ -222,6 +223,12 @@ static int probe_dos_pt(blkid_probe pr,
 		goto nothing;
 	}
 
+	/* Another false possitive is NTFS */
+	if (blkid_probe_is_ntfs(pr) == 1) {
+		DBG(LOWPROBE, ul_debug("probably NTFS -- ignore"));
+		goto nothing;
+	}
+
 	/*
 	 * Ugly exception, if the device contains a valid LVM physical volume
 	 * and empty MBR (=no partition defined) then it's LVM and MBR should
diff --git a/libblkid/src/superblocks/ntfs.c b/libblkid/src/superblocks/ntfs.c
index 5ea2a454a..90a102f89 100644
--- a/libblkid/src/superblocks/ntfs.c
+++ b/libblkid/src/superblocks/ntfs.c
@@ -78,7 +78,7 @@ struct file_attribute {
 #define	MFT_RECORD_ATTR_VOLUME_NAME	0x60
 #define	MFT_RECORD_ATTR_END		0xffffffff
 
-static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
+static int __probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag, int save_info)
 {
 	struct ntfs_super_block *ns;
 	struct master_file_table_record *mft;
@@ -174,6 +174,10 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
 	if (memcmp(buf_mft, "FILE", 4))
 		return 1;
 
+	/* return if caller does not care about UUID and LABEL */
+	if (!save_info)
+		return 0;
+
 	mft = (struct master_file_table_record *) buf_mft;
 	attr_off = le16_to_cpu(mft->attrs_offset);
 
@@ -211,6 +215,24 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
 	return 0;
 }
 
+static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
+{
+	return __probe_ntfs(pr, mag, 1);
+}
+
+int blkid_probe_is_ntfs(blkid_probe pr)
+{
+	const struct blkid_idmag *mag = NULL;
+	int rc;
+
+	rc = blkid_probe_get_idmag(pr, &ntfs_idinfo, NULL, &mag);
+	if (rc < 0)
+		return rc;	/* error */
+	if (rc != BLKID_PROBE_OK || !mag)
+		return 0;
+
+	return __probe_ntfs(pr, mag, 0) == 0 ? 1 : 0;
+}
 
 const struct blkid_idinfo ntfs_idinfo =
 {
diff --git a/libblkid/src/superblocks/superblocks.h b/libblkid/src/superblocks/superblocks.h
index 3313d0245..59682c86d 100644
--- a/libblkid/src/superblocks/superblocks.h
+++ b/libblkid/src/superblocks/superblocks.h
@@ -109,5 +109,6 @@ extern int blkid_probe_set_utf8_id_label(blkid_probe pr, const char *name,
 			     const unsigned char *data, size_t len, int enc);
 
 extern int blkid_probe_is_bitlocker(blkid_probe pr);
+extern int blkid_probe_is_ntfs(blkid_probe pr);
 
 #endif /* _BLKID_SUPERBLOCKS_H */
-- 
cgit v1.2.3-55-g7522