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2009-02-07 Robert Millan <rmh@aybabtu.com>

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* fs/ext2.c (grub_ext2_mount): Avoid mounting filesystems with
        backward-incompatible features.

        Based on patch from Javier Martín, with some adjustments.
This commit is contained in:
robertmh 2009-02-07 23:13:48 +00:00
parent cea15bca5b
commit aebfc4b085
2 changed files with 66 additions and 3 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2009-02-07 Robert Millan <rmh@aybabtu.com>
* fs/ext2.c (grub_ext2_mount): Avoid mounting filesystems with
backward-incompatible features.
Based on patch from Javier Martín, with some adjustments.
2009-02-07 Michael Scherer <misc@mandriva.org>
* fs/hfs.c (grub_hfsplus_iterate_dir): Treat hfs+ as case insensitive.

62
fs/ext2.c
View file

@ -71,7 +71,52 @@
? EXT2_GOOD_OLD_INODE_SIZE \
: grub_le_to_cpu16 (data->sblock.inode_size))
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
/* Superblock filesystem feature flags (RW compatible)
* A filesystem with any of these enabled can be read and written by a driver
* that does not understand them without causing metadata/data corruption */
#define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
#define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
#define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008
#define EXT2_FEATURE_COMPAT_RESIZE_INODE 0x0010
#define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020
/* Superblock filesystem feature flags (RO compatible)
* A filesystem with any of these enabled can be safely read by a driver that
* does not understand them, but should not be written to, usually because
* additional metadata is required */
#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0010
#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK 0x0020
#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE 0x0040
/* Superblock filesystem feature flags (back-incompatible)
* A filesystem with any of these enabled should not be attempted to be read
* by a driver that does not understand them, since they usually indicate
* metadata format changes that might confuse the reader. */
#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004 /* Needs recovery */
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Volume is journal device */
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* Extents used */
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
/* The set of back-incompatible features this driver DOES support. Add (OR)
* flags here as the related features are implemented into the driver */
#define EXT2_DRIVER_SUPPORTED_INCOMPAT ( EXT2_FEATURE_INCOMPAT_FILETYPE \
| EXT4_FEATURE_INCOMPAT_EXTENTS )
/* List of rationales for the ignored "incompatible" features:
* needs_recovery: Not really back-incompatible - was added as such to forbid
* ext2 drivers from mounting an ext3 volume with a dirty
* journal because they will ignore the journal, but the next
* ext3 driver to mount the volume will find the journal and
* replay it, potentially corrupting the metadata written by
* the ext2 drivers
*/
#define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER )
#define EXT3_JOURNAL_MAGIC_NUMBER 0xc03b3998U
@ -503,7 +548,19 @@ grub_ext2_mount (grub_disk_t disk)
/* Make sure this is an ext2 filesystem. */
if (grub_le_to_cpu16 (data->sblock.magic) != EXT2_MAGIC)
goto fail;
{
grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
goto fail;
}
/* Check the FS doesn't have feature bits enabled that we don't support. */
if (grub_le_to_cpu32 (data->sblock.feature_incompat)
& ~(EXT2_DRIVER_SUPPORTED_INCOMPAT | EXT2_DRIVER_IGNORED_INCOMPAT))
{
grub_error (GRUB_ERR_BAD_FS, "filesystem has unsupported incompatible features");
goto fail;
}
data->disk = disk;
@ -520,7 +577,6 @@ grub_ext2_mount (grub_disk_t disk)
return data;
fail:
grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
grub_free (data);
return 0;
}