udf: disallow RW mount without valid integrity descriptor
Refuse to mount a volume read-write without a coherent Logical Volume
Integrity Descriptor, because we can't generate truly unique IDs without
one.
This fixes a bug where all inodes created on a UDF filesystem following
mount without a coherent LVID are assigned unique ID 0 which can then
confuse other UDF implementations.
Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 2cf435c..a6940d9 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1474,6 +1474,17 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
if (lvd->integritySeqExt.extLength)
udf_load_logicalvolint(sb, leea_to_cpu(lvd->integritySeqExt));
ret = 0;
+
+ if (!sbi->s_lvid_bh) {
+ /* We can't generate unique IDs without a valid LVID */
+ if (sb_rdonly(sb)) {
+ UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
+ } else {
+ udf_warn(sb, "Damaged or missing LVID, forcing "
+ "readonly mount\n");
+ ret = -EACCES;
+ }
+ }
out_bh:
brelse(bh);
return ret;
