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udf: reduce leakage of blocks related to named streams 

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>
This commit is contained in:
Steven J. Magnani 2019-08-14 07:50:02 -05:00 committed by Jan Kara
parent 56db199169
commit ab9a3a7372
3 changed files with 29 additions and 2 deletions
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24
fs/udf/inode.c
View File

@ -1485,6 +1485,8 @@ reread:
iinfo->i_lenEAttr = le32_to_cpu(fe->lengthExtendedAttr);
iinfo->i_lenAlloc = le32_to_cpu(fe->lengthAllocDescs);
iinfo->i_checkpoint = le32_to_cpu(fe->checkpoint);
iinfo->i_streamdir = 0;
iinfo->i_lenStreams = 0;
} else {
inode->i_blocks = le64_to_cpu(efe->logicalBlocksRecorded) <<
(inode->i_sb->s_blocksize_bits - 9);
@ -1498,6 +1500,16 @@ reread:
iinfo->i_lenEAttr = le32_to_cpu(efe->lengthExtendedAttr);
iinfo->i_lenAlloc = le32_to_cpu(efe->lengthAllocDescs);
iinfo->i_checkpoint = le32_to_cpu(efe->checkpoint);
/* Named streams */
iinfo->i_streamdir = (efe->streamDirectoryICB.extLength != 0);
iinfo->i_locStreamdir =
lelb_to_cpu(efe->streamDirectoryICB.extLocation);
iinfo->i_lenStreams = le64_to_cpu(efe->objectSize);
if (iinfo->i_lenStreams >= inode->i_size)
iinfo->i_lenStreams -= inode->i_size;
else
iinfo->i_lenStreams = 0;
}
inode->i_generation = iinfo->i_unique;
@ -1760,9 +1772,19 @@ static int udf_update_inode(struct inode *inode, int do_sync)
iinfo->i_ext.i_data,
inode->i_sb->s_blocksize -
sizeof(struct extendedFileEntry));
efe->objectSize = cpu_to_le64(inode->i_size);
efe->objectSize =
cpu_to_le64(inode->i_size + iinfo->i_lenStreams);
efe->logicalBlocksRecorded = cpu_to_le64(lb_recorded);
if (iinfo->i_streamdir) {
struct long_ad *icb_lad = &efe->streamDirectoryICB;
icb_lad->extLocation =
cpu_to_lelb(iinfo->i_locStreamdir);
icb_lad->extLength =
cpu_to_le32(inode->i_sb->s_blocksize);
}
udf_adjust_time(iinfo, inode->i_atime);
udf_adjust_time(iinfo, inode->i_mtime);
udf_adjust_time(iinfo, inode->i_ctime);

2
fs/udf/super.c
View File

@ -151,9 +151,11 @@ static struct inode *udf_alloc_inode(struct super_block *sb)
ei->i_unique = 0;
ei->i_lenExtents = 0;
ei->i_lenStreams = 0;
ei->i_next_alloc_block = 0;
ei->i_next_alloc_goal = 0;
ei->i_strat4096 = 0;
ei->i_streamdir = 0;
init_rwsem(&ei->i_data_sem);
ei->cached_extent.lstart = -1;
spin_lock_init(&ei->i_extent_cache_lock);

5
fs/udf/udf_i.h
View File

@ -42,12 +42,15 @@ struct udf_inode_info {
unsigned i_efe : 1; /* extendedFileEntry */
unsigned i_use : 1; /* unallocSpaceEntry */
unsigned i_strat4096 : 1;
unsigned reserved : 26;
unsigned i_streamdir : 1;
unsigned reserved : 25;
union {
struct short_ad *i_sad;
struct long_ad *i_lad;
__u8 *i_data;
} i_ext;
struct kernel_lb_addr i_locStreamdir;
__u64 i_lenStreams;
struct rw_semaphore i_data_sem;
struct udf_ext_cache cached_extent;
/* Spinlock for protecting extent cache */