[ Upstream commit a4a8b99ec819ca60b49dc582a4287ef03411f117 ]

Free space on filesystems with metadata or virtual partition maps
currently gets misreported. This is because these partitions are just
remapped onto underlying real partitions from which keep track of free
blocks. Take this remapping into account when counting free blocks as
well.

Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reported-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 15fb05fd286ac57a0802d71624daeb5c1c2d5b07 ]

UDF 2.60 standard states in section 2.2.14.2:

    A partition with Access Type 3 (rewritable) shall define a Freed
    Space Bitmap or a Freed Space Table, see 2.3.3. All other partitions
    shall not define a Freed Space Bitmap or a Freed Space Table.

    Rewritable partitions are used on media that require some form of
    preprocessing before re-writing data (for example legacy MO). Such
    partitions shall use Access Type 3.

    Overwritable partitions are used on media that do not require
    preprocessing before overwriting data (for example: CD-RW, DVD-RW,
    DVD+RW, DVD-RAM, BD-RE, HD DVD-Rewritable). Such partitions shall
    use Access Type 4.

however older versions of the standard didn't have this wording and
there are tools out there that create UDF filesystems with rewritable
partitions but that don't contain a Freed Space Bitmap or a Freed Space
Table on media that does not require pre-processing before overwriting a
block. So instead of forcing media with rewritable partition read-only,
base this decision on presence of a Freed Space Bitmap or a Freed Space
Table.

Reported-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Fixes: b085fbe2ef7f ("udf: Fix crash during mount")
Link: https://lore.kernel.org/linux-fsdevel/20200112144735.hj2emsoy4uwsouxz@pali
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>

The brelse() function tests whether its argument is NULL
and then returns immediately.
Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Link: https://lore.kernel.org/r/a254c1d1-0109-ab51-c67a-edc5c1c4b4cd@web.de
Signed-off-by: Jan Kara <jack@suse.cz>

Move some functions to make forward declarations unnecessary.

Signed-off-by: Jan Kara <jack@suse.cz>

OSTA UDF standard defines that domain identifier in logical volume
descriptor and file set descriptor should contain a particular string
and the identifier suffix contains flags possibly making media
write-protected. Verify these constraints and allow only read-only mount
if they are not met.

Tested-by: Steven J. Magnani <steve@digidescorp.com>
Reviewed-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Windows presents files created within Linux as read-only, even when
permissions in Linux indicate the file should be writable.

UDF defines a slightly different set of basic file permissions than Linux.
Specifically, UDF has "delete" and "change attribute" permissions for each
access class (user/group/other). Linux has no equivalents for these.

When the Linux UDF driver creates a file (or directory), no UDF delete or
change attribute permissions are granted. The lack of delete permission
appears to cause Windows to mark an item read-only when its permissions
otherwise indicate that it should be read-write.

Fix this by having UDF delete permissions track Linux write permissions.
Also grant UDF change attribute permission to the owner when creating a
new inode.

Reported by: Ty Young
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Link: https://lore.kernel.org/r/20190827121359.9954-1-steve@digidescorp.com
Signed-off-by: Jan Kara <jack@suse.cz>

Instead of relying on UDFFS_DEBUG define for debug printing, just use
standard pr_debug() prints and rely on CONFIG_DYNAMIC_DEBUG
infrastructure for enabling or disabling prints.

Signed-off-by: Jan Kara <jack@suse.cz>

Windows is capable of creating UDF files having named streams.
One example is the "Zone.Identifier" stream attached automatically
to files downloaded from a network. See:
  https://msdn.microsoft.com/en-us/library/dn392609.aspx

Modification of a file having one or more named streams in Linux causes
the stream directory to become detached from the file, essentially leaking
all blocks pertaining to the file's streams.

Fix by saving off information about an inode's streams when reading it,
for later use when its on-disk data is updated.

Link: https://lore.kernel.org/r/20190814125002.10869-1-steve@digidescorp.com
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Jan Kara <jack@suse.cz>

The UDF bitmap allocation code assumes that a recorded
Unallocated Space Bitmap is compliant with ECMA-167 4/13,
which requires that pad bytes between the end of the bitmap
and the end of a logical block are all zero.

When a recorded bitmap does not comply with this requirement,
for example one padded with FF to the block boundary instead
of 00, the allocator may "allocate" blocks that are outside
the UDF partition extent. This can result in UDF volume descriptors
being overwritten by file data or by partition-level descriptors,
and in extreme cases, even in scribbling on a subsequent disk partition.

Add a check that the block selected by the allocator actually
resides within the UDF partition extent.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>

Link: https://lore.kernel.org/r/1564341552-129750-1-git-send-email-steve@digidescorp.com
Signed-off-by: Jan Kara <jack@suse.cz>

Some UDF creators (specifically Microsoft, but perhaps others) mishandle
the ECMA-167 corner case that requires descriptors within a Volume
Recognition Sequence to be placed at 4096-byte intervals on media where
the block size is 4K. Instead, the descriptors are placed at the 2048-
byte interval mandated for media with smaller blocks. This nonconformity
currently prevents Linux from recognizing the filesystem as UDF.

Modify the driver to tolerate a misformatted VRS on 4K media.

[JK: Simplified descriptor checking]
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Tested-by: Steven J. Magnani <steve@digidescorp.com>
Link: https://lore.kernel.org/r/20190711133852.16887-2-steve@digidescorp.com
Signed-off-by: Jan Kara <jack@suse.cz>