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| author | Jan Kara <jack@suse.cz> | 2018-09-06 15:56:10 +0200 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2018-09-07 10:32:22 +0200 |
| commit | a9ad01bc759df79b0012f43ee52164391e31cd96 (patch) | |
| tree | f1c661d0ea79df14520453b5439a19e117892065 /fs | |
| parent | 59fed3bf8a461ab07a8e57b42b6402e984c7cc62 (diff) | |
| download | linux-a9ad01bc759df79b0012f43ee52164391e31cd96.tar.gz linux-a9ad01bc759df79b0012f43ee52164391e31cd96.tar.bz2 linux-a9ad01bc759df79b0012f43ee52164391e31cd96.zip | |
udf: Prevent write-unsupported filesystem to be remounted read-write
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/udf/super.c | 30 | ||||
| -rw-r--r-- | 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 |