From: Jan Kara <jack@suse.cz>
To: <linux-fsdevel@vger.kernel.org>
Cc: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>,
Jan Kara <jack@suse.cz>
Subject: [PATCH 1/4] udf: Prevent write-unsupported filesystem to be remounted read-write
Date: Thu, 6 Sep 2018 18:18:18 +0200 [thread overview]
Message-ID: <20180906161821.11603-2-jack@suse.cz> (raw)
In-Reply-To: <20180906161821.11603-1-jack@suse.cz>
There are certain filesystem features which we support for reading but
not for writing. We properly refuse to mount such filesystems read-write
however for some features (such as read-only partitions), we don't check
for these features when remounting the filesystem from read-only to
read-write. Thus such filesystems could be remounted read-write leading
to strange behavior (most likely crashes).
Fix the problem by marking in superblock whether the filesystem has some
features that are supported in read-only mode and check this flag during
remount.
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/udf/super.c | 30 ++++++++++++++++--------------
fs/udf/udf_sb.h | 2 ++
2 files changed, 18 insertions(+), 14 deletions(-)
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 6f515651a2c2..b997e3116e37 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -613,14 +613,11 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
struct udf_options uopt;
struct udf_sb_info *sbi = UDF_SB(sb);
int error = 0;
- struct logicalVolIntegrityDescImpUse *lvidiu = udf_sb_lvidiu(sb);
+
+ if (!(*flags & SB_RDONLY) && UDF_QUERY_FLAG(sb, UDF_FLAG_RW_INCOMPAT))
+ return -EACCES;
sync_filesystem(sb);
- if (lvidiu) {
- int write_rev = le16_to_cpu(lvidiu->minUDFWriteRev);
- if (write_rev > UDF_MAX_WRITE_VERSION && !(*flags & SB_RDONLY))
- return -EACCES;
- }
uopt.flags = sbi->s_flags;
uopt.uid = sbi->s_uid;
@@ -1257,6 +1254,7 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
ret = -EACCES;
goto out_bh;
}
+ UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
ret = udf_load_vat(sb, i, type1_idx);
if (ret < 0)
goto out_bh;
@@ -2155,10 +2153,12 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
UDF_MAX_READ_VERSION);
ret = -EINVAL;
goto error_out;
- } else if (minUDFWriteRev > UDF_MAX_WRITE_VERSION &&
- !sb_rdonly(sb)) {
- ret = -EACCES;
- goto error_out;
+ } else if (minUDFWriteRev > UDF_MAX_WRITE_VERSION) {
+ if (!sb_rdonly(sb)) {
+ ret = -EACCES;
+ goto error_out;
+ }
+ UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
}
sbi->s_udfrev = minUDFWriteRev;
@@ -2176,10 +2176,12 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
}
if (sbi->s_partmaps[sbi->s_partition].s_partition_flags &
- UDF_PART_FLAG_READ_ONLY &&
- !sb_rdonly(sb)) {
- ret = -EACCES;
- goto error_out;
+ UDF_PART_FLAG_READ_ONLY) {
+ if (!sb_rdonly(sb)) {
+ ret = -EACCES;
+ goto error_out;
+ }
+ UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
}
if (udf_find_fileset(sb, &fileset, &rootdir)) {
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 9424d7cab790..d12e507e9eb2 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -30,6 +30,8 @@
#define UDF_FLAG_LASTBLOCK_SET 16
#define UDF_FLAG_BLOCKSIZE_SET 17
#define UDF_FLAG_INCONSISTENT 18
+#define UDF_FLAG_RW_INCOMPAT 19 /* Set when we find RW incompatible
+ * feature */
#define UDF_PART_FLAG_UNALLOC_BITMAP 0x0001
#define UDF_PART_FLAG_UNALLOC_TABLE 0x0002
--
2.16.4
next prev parent reply other threads:[~2018-09-06 20:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 16:18 [PATCH 0/4] udf: Fix crash during mount Jan Kara
2018-09-06 16:18 ` Jan Kara [this message]
2018-09-06 16:18 ` [PATCH 2/4] " Jan Kara
2018-09-06 16:18 ` [PATCH 3/4] udf: Drop freed bitmap / table support Jan Kara
2018-09-06 16:18 ` [PATCH 4/4] udf: Drop pack pragma from udf_sb.h Jan Kara
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180906161821.11603-2-jack@suse.cz \
--to=jack@suse.cz \
--cc=anatoly.trosinenko@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).