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grub/grub-core/fs/ext2.c
Eric Biggers 734668238f Allow GRUB to mount ext2/3/4 filesystems that have the encryption feature. 
On such a filesystem, inodes may have EXT4_ENCRYPT_FLAG set.
For a regular file, this means its contents are encrypted; for a
directory, this means the filenames in its directory entries are
encrypted; and for a symlink, this means its target is encrypted.  Since
GRUB cannot decrypt encrypted contents or filenames, just issue an error
if it would need to do so.  This is sufficient to allow unencrypted boot
files to co-exist with encrypted files elsewhere on the filesystem.

(Note that encrypted regular files and symlinks will not normally be
encountered outside an encrypted directory; however, it's possible via
hard links, so they still need to be handled.)

Tested by booting from an ext4 /boot partition on which I had run
'tune2fs -O encrypt'.  I also verified that the expected error messages
are printed when trying to access encrypted directories, files, and
symlinks from the GRUB command line.  Also ran 'sudo ./grub-fs-tester
ext4_encrypt'; note that this requires e2fsprogs v1.43+ and Linux v4.1+.

Signed-off-by: Eric Biggers <ebiggers@google.com>
2017-06-29 13:29:53 +00:00

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/* ext2.c - Second Extended filesystem */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003,2004,2005,2007,2008,2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/* Magic value used to identify an ext2 filesystem. */
#define EXT2_MAGIC 0xEF53
/* Amount of indirect blocks in an inode. */
#define INDIRECT_BLOCKS 12
/* The good old revision and the default inode size. */
#define EXT2_GOOD_OLD_REVISION 0
#define EXT2_GOOD_OLD_INODE_SIZE 128
/* Filetype used in directory entry. */
#define FILETYPE_UNKNOWN 0
#define FILETYPE_REG 1
#define FILETYPE_DIRECTORY 2
#define FILETYPE_SYMLINK 7
/* Filetype information as used in inodes. */
#define FILETYPE_INO_MASK 0170000
#define FILETYPE_INO_REG 0100000
#define FILETYPE_INO_DIRECTORY 0040000
#define FILETYPE_INO_SYMLINK 0120000
#include <grub/err.h>
#include <grub/file.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/disk.h>
#include <grub/dl.h>
#include <grub/types.h>
#include <grub/fshelp.h>
GRUB_MOD_LICENSE ("GPLv3+");
/* Log2 size of ext2 block in 512 blocks. */
#define LOG2_EXT2_BLOCK_SIZE(data) \
(grub_le_to_cpu32 (data->sblock.log2_block_size) + 1)
/* Log2 size of ext2 block in bytes. */
#define LOG2_BLOCK_SIZE(data) \
(grub_le_to_cpu32 (data->sblock.log2_block_size) + 10)
/* The size of an ext2 block in bytes. */
#define EXT2_BLOCK_SIZE(data) (1U << LOG2_BLOCK_SIZE (data))
/* The revision level. */
#define EXT2_REVISION(data) grub_le_to_cpu32 (data->sblock.revision_level)
/* The inode size. */
#define EXT2_INODE_SIZE(data) \
(data->sblock.revision_level \
== grub_cpu_to_le32_compile_time (EXT2_GOOD_OLD_REVISION) \
? EXT2_GOOD_OLD_INODE_SIZE \
: grub_le_to_cpu16 (data->sblock.inode_size))
/* 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_MMP 0x0100
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
#define EXT4_FEATURE_INCOMPAT_ENCRYPT 0x10000
/* 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 \
| EXT4_FEATURE_INCOMPAT_FLEX_BG \
| EXT2_FEATURE_INCOMPAT_META_BG \
| EXT4_FEATURE_INCOMPAT_64BIT \
| EXT4_FEATURE_INCOMPAT_ENCRYPT)
/* 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. Safe to ignore for this RO driver.
* mmp: Not really back-incompatible - was added as such to
* avoid multiple read-write mounts. Safe to ignore for this
* RO driver.
*/
#define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER \
| EXT4_FEATURE_INCOMPAT_MMP)
#define EXT3_JOURNAL_MAGIC_NUMBER 0xc03b3998U
#define EXT3_JOURNAL_DESCRIPTOR_BLOCK 1
#define EXT3_JOURNAL_COMMIT_BLOCK 2
#define EXT3_JOURNAL_SUPERBLOCK_V1 3
#define EXT3_JOURNAL_SUPERBLOCK_V2 4
#define EXT3_JOURNAL_REVOKE_BLOCK 5
#define EXT3_JOURNAL_FLAG_ESCAPE 1
#define EXT3_JOURNAL_FLAG_SAME_UUID 2
#define EXT3_JOURNAL_FLAG_DELETED 4
#define EXT3_JOURNAL_FLAG_LAST_TAG 8
#define EXT4_ENCRYPT_FLAG 0x800
#define EXT4_EXTENTS_FLAG 0x80000
/* The ext2 superblock. */
struct grub_ext2_sblock
{
grub_uint32_t total_inodes;
grub_uint32_t total_blocks;
grub_uint32_t reserved_blocks;
grub_uint32_t free_blocks;
grub_uint32_t free_inodes;
grub_uint32_t first_data_block;
grub_uint32_t log2_block_size;
grub_uint32_t log2_fragment_size;
grub_uint32_t blocks_per_group;
grub_uint32_t fragments_per_group;
grub_uint32_t inodes_per_group;
grub_uint32_t mtime;
grub_uint32_t utime;
grub_uint16_t mnt_count;
grub_uint16_t max_mnt_count;
grub_uint16_t magic;
grub_uint16_t fs_state;
grub_uint16_t error_handling;
grub_uint16_t minor_revision_level;
grub_uint32_t lastcheck;
grub_uint32_t checkinterval;
grub_uint32_t creator_os;
grub_uint32_t revision_level;
grub_uint16_t uid_reserved;
grub_uint16_t gid_reserved;
grub_uint32_t first_inode;
grub_uint16_t inode_size;
grub_uint16_t block_group_number;
grub_uint32_t feature_compatibility;
grub_uint32_t feature_incompat;
grub_uint32_t feature_ro_compat;
grub_uint16_t uuid[8];
char volume_name[16];
char last_mounted_on[64];
grub_uint32_t compression_info;
grub_uint8_t prealloc_blocks;
grub_uint8_t prealloc_dir_blocks;
grub_uint16_t reserved_gdt_blocks;
grub_uint8_t journal_uuid[16];
grub_uint32_t journal_inum;
grub_uint32_t journal_dev;
grub_uint32_t last_orphan;
grub_uint32_t hash_seed[4];
grub_uint8_t def_hash_version;
grub_uint8_t jnl_backup_type;
grub_uint16_t group_desc_size;
grub_uint32_t default_mount_opts;
grub_uint32_t first_meta_bg;
grub_uint32_t mkfs_time;
grub_uint32_t jnl_blocks[17];
};
/* The ext2 blockgroup. */
struct grub_ext2_block_group
{
grub_uint32_t block_id;
grub_uint32_t inode_id;
grub_uint32_t inode_table_id;
grub_uint16_t free_blocks;
grub_uint16_t free_inodes;
grub_uint16_t used_dirs;
grub_uint16_t pad;
grub_uint32_t reserved[3];
grub_uint32_t block_id_hi;
grub_uint32_t inode_id_hi;
grub_uint32_t inode_table_id_hi;
grub_uint16_t free_blocks_hi;
grub_uint16_t free_inodes_hi;
grub_uint16_t used_dirs_hi;
grub_uint16_t pad2;
grub_uint32_t reserved2[3];
};
/* The ext2 inode. */
struct grub_ext2_inode
{
grub_uint16_t mode;
grub_uint16_t uid;
grub_uint32_t size;
grub_uint32_t atime;
grub_uint32_t ctime;
grub_uint32_t mtime;
grub_uint32_t dtime;
grub_uint16_t gid;
grub_uint16_t nlinks;
grub_uint32_t blockcnt; /* Blocks of 512 bytes!! */
grub_uint32_t flags;
grub_uint32_t osd1;
union
{
struct datablocks
{
grub_uint32_t dir_blocks[INDIRECT_BLOCKS];
grub_uint32_t indir_block;
grub_uint32_t double_indir_block;
grub_uint32_t triple_indir_block;
} blocks;
char symlink[60];
};
grub_uint32_t version;
grub_uint32_t acl;
grub_uint32_t size_high;
grub_uint32_t fragment_addr;
grub_uint32_t osd2[3];
};
/* The header of an ext2 directory entry. */
struct ext2_dirent
{
grub_uint32_t inode;
grub_uint16_t direntlen;
#define MAX_NAMELEN 255
grub_uint8_t namelen;
grub_uint8_t filetype;
};
struct grub_ext3_journal_header
{
grub_uint32_t magic;
grub_uint32_t block_type;
grub_uint32_t sequence;
};
struct grub_ext3_journal_revoke_header
{
struct grub_ext3_journal_header header;
grub_uint32_t count;
grub_uint32_t data[0];
};
struct grub_ext3_journal_block_tag
{
grub_uint32_t block;
grub_uint32_t flags;
};
struct grub_ext3_journal_sblock
{
struct grub_ext3_journal_header header;
grub_uint32_t block_size;
grub_uint32_t maxlen;
grub_uint32_t first;
grub_uint32_t sequence;
grub_uint32_t start;
};
#define EXT4_EXT_MAGIC 0xf30a
struct grub_ext4_extent_header
{
grub_uint16_t magic;
grub_uint16_t entries;
grub_uint16_t max;
grub_uint16_t depth;
grub_uint32_t generation;
};
struct grub_ext4_extent
{
grub_uint32_t block;
grub_uint16_t len;
grub_uint16_t start_hi;
grub_uint32_t start;
};
struct grub_ext4_extent_idx
{
grub_uint32_t block;
grub_uint32_t leaf;
grub_uint16_t leaf_hi;
grub_uint16_t unused;
};
struct grub_fshelp_node
{
struct grub_ext2_data *data;
struct grub_ext2_inode inode;
int ino;
int inode_read;
};
/* Information about a "mounted" ext2 filesystem. */
struct grub_ext2_data
{
struct grub_ext2_sblock sblock;
int log_group_desc_size;
grub_disk_t disk;
struct grub_ext2_inode *inode;
struct grub_fshelp_node diropen;
};
static grub_dl_t my_mod;
/* Check is a = b^x for some x. */
static inline int
is_power_of (grub_uint64_t a, grub_uint32_t b)
{
grub_uint64_t c;
/* Prevent overflow assuming b < 8. */
if (a >= (1LL << 60))
return 0;
for (c = 1; c <= a; c *= b);
return (c == a);
}
static inline int
group_has_super_block (struct grub_ext2_data *data, grub_uint64_t group)
{
if (!(data->sblock.feature_ro_compat
& grub_cpu_to_le32_compile_time(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)))
return 1;
/* Algorithm looked up in Linux source. */
if (group <= 1)
return 1;
/* Even number is never a power of odd number. */
if (!(group & 1))
return 0;
return (is_power_of(group, 7) || is_power_of(group, 5) ||
is_power_of(group, 3));
}
/* Read into BLKGRP the blockgroup descriptor of blockgroup GROUP of
the mounted filesystem DATA. */
inline static grub_err_t
grub_ext2_blockgroup (struct grub_ext2_data *data, grub_uint64_t group,
struct grub_ext2_block_group *blkgrp)
{
grub_uint64_t full_offset = (group << data->log_group_desc_size);
grub_uint64_t block, offset;
block = (full_offset >> LOG2_BLOCK_SIZE (data));
offset = (full_offset & ((1 << LOG2_BLOCK_SIZE (data)) - 1));
if ((data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (EXT2_FEATURE_INCOMPAT_META_BG))
&& block >= grub_le_to_cpu32(data->sblock.first_meta_bg))
{
grub_uint64_t first_block_group;
/* Find the first block group for which a descriptor
is stored in given block. */
first_block_group = (block << (LOG2_BLOCK_SIZE (data)
- data->log_group_desc_size));
block = (first_block_group
* grub_le_to_cpu32(data->sblock.blocks_per_group));
if (group_has_super_block (data, first_block_group))
block++;
}
else
/* Superblock. */
block++;
return grub_disk_read (data->disk,
((grub_le_to_cpu32 (data->sblock.first_data_block)
+ block)
<< LOG2_EXT2_BLOCK_SIZE (data)), offset,
sizeof (struct grub_ext2_block_group), blkgrp);
}
static struct grub_ext4_extent_header *
grub_ext4_find_leaf (struct grub_ext2_data *data,
struct grub_ext4_extent_header *ext_block,
grub_uint32_t fileblock)
{
struct grub_ext4_extent_idx *index;
void *buf = NULL;
while (1)
{
int i;
grub_disk_addr_t block;
index = (struct grub_ext4_extent_idx *) (ext_block + 1);
if (ext_block->magic != grub_cpu_to_le16_compile_time (EXT4_EXT_MAGIC))
goto fail;
if (ext_block->depth == 0)
return ext_block;
for (i = 0; i < grub_le_to_cpu16 (ext_block->entries); i++)
{
if (fileblock < grub_le_to_cpu32(index[i].block))
break;
}
if (--i < 0)
goto fail;
block = grub_le_to_cpu16 (index[i].leaf_hi);
block = (block << 32) | grub_le_to_cpu32 (index[i].leaf);
if (!buf)
buf = grub_malloc (EXT2_BLOCK_SIZE(data));
if (!buf)
goto fail;
if (grub_disk_read (data->disk,
block << LOG2_EXT2_BLOCK_SIZE (data),
0, EXT2_BLOCK_SIZE(data), buf))
goto fail;
ext_block = buf;
}
fail:
grub_free (buf);
return 0;
}
static grub_disk_addr_t
grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
{
struct grub_ext2_data *data = node->data;
struct grub_ext2_inode *inode = &node->inode;
unsigned int blksz = EXT2_BLOCK_SIZE (data);
grub_disk_addr_t blksz_quarter = blksz / 4;
int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
int log_perblock = log2_blksz + 9 - 2;
grub_uint32_t indir;
int shift;
if (inode->flags & grub_cpu_to_le32_compile_time (EXT4_EXTENTS_FLAG))
{
struct grub_ext4_extent_header *leaf;
struct grub_ext4_extent *ext;
int i;
grub_disk_addr_t ret;
leaf = grub_ext4_find_leaf (data, (struct grub_ext4_extent_header *) inode->blocks.dir_blocks, fileblock);
if (! leaf)
{
grub_error (GRUB_ERR_BAD_FS, "invalid extent");
return -1;
}
ext = (struct grub_ext4_extent *) (leaf + 1);
for (i = 0; i < grub_le_to_cpu16 (leaf->entries); i++)
{
if (fileblock < grub_le_to_cpu32 (ext[i].block))
break;
}
if (--i >= 0)
{
fileblock -= grub_le_to_cpu32 (ext[i].block);
if (fileblock >= grub_le_to_cpu16 (ext[i].len))
ret = 0;
else
{
grub_disk_addr_t start;
start = grub_le_to_cpu16 (ext[i].start_hi);
start = (start << 32) + grub_le_to_cpu32 (ext[i].start);
ret = fileblock + start;
}
}
else
{
grub_error (GRUB_ERR_BAD_FS, "something wrong with extent");
ret = -1;
}
if (leaf != (struct grub_ext4_extent_header *) inode->blocks.dir_blocks)
grub_free (leaf);
return ret;
}
/* Direct blocks. */
if (fileblock < INDIRECT_BLOCKS)
return grub_le_to_cpu32 (inode->blocks.dir_blocks[fileblock]);
fileblock -= INDIRECT_BLOCKS;
/* Indirect. */
if (fileblock < blksz_quarter)
{
indir = inode->blocks.indir_block;
shift = 0;
goto indirect;
}
fileblock -= blksz_quarter;
/* Double indirect. */
if (fileblock < blksz_quarter * blksz_quarter)
{
indir = inode->blocks.double_indir_block;
shift = 1;
goto indirect;
}
fileblock -= blksz_quarter * blksz_quarter;
/* Triple indirect. */
if (fileblock < blksz_quarter * blksz_quarter * (blksz_quarter + 1))
{
indir = inode->blocks.triple_indir_block;
shift = 2;
goto indirect;
}
grub_error (GRUB_ERR_BAD_FS,
"ext2fs doesn't support quadruple indirect blocks");
return -1;
indirect:
do {
/* If the indirect block is zero, all child blocks are absent
(i.e. filled with zeros.) */
if (indir == 0)
return 0;
if (grub_disk_read (data->disk,
((grub_disk_addr_t) grub_le_to_cpu32 (indir))
<< log2_blksz,
((fileblock >> (log_perblock * shift))
& ((1 << log_perblock) - 1))
* sizeof (indir),
sizeof (indir), &indir))
return -1;
} while (shift--);
return grub_le_to_cpu32 (indir);
}
/* Read LEN bytes from the file described by DATA starting with byte
POS. Return the amount of read bytes in READ. */
static grub_ssize_t
grub_ext2_read_file (grub_fshelp_node_t node,
grub_disk_read_hook_t read_hook, void *read_hook_data,
grub_off_t pos, grub_size_t len, char *buf)
{
return grub_fshelp_read_file (node->data->disk, node,
read_hook, read_hook_data,
pos, len, buf, grub_ext2_read_block,
grub_cpu_to_le32 (node->inode.size)
| (((grub_off_t) grub_cpu_to_le32 (node->inode.size_high)) << 32),
LOG2_EXT2_BLOCK_SIZE (node->data), 0);
}
/* Read the inode INO for the file described by DATA into INODE. */
static grub_err_t
grub_ext2_read_inode (struct grub_ext2_data *data,
int ino, struct grub_ext2_inode *inode)
{
struct grub_ext2_block_group blkgrp;
struct grub_ext2_sblock *sblock = &data->sblock;
int inodes_per_block;
unsigned int blkno;
unsigned int blkoff;
grub_disk_addr_t base;
/* It is easier to calculate if the first inode is 0. */
ino--;
grub_ext2_blockgroup (data,
ino / grub_le_to_cpu32 (sblock->inodes_per_group),
&blkgrp);
if (grub_errno)
return grub_errno;
inodes_per_block = EXT2_BLOCK_SIZE (data) / EXT2_INODE_SIZE (data);
blkno = (ino % grub_le_to_cpu32 (sblock->inodes_per_group))
/ inodes_per_block;
blkoff = (ino % grub_le_to_cpu32 (sblock->inodes_per_group))
% inodes_per_block;
base = grub_le_to_cpu32 (blkgrp.inode_table_id);
if (data->log_group_desc_size >= 6)
base |= (((grub_disk_addr_t) grub_le_to_cpu32 (blkgrp.inode_table_id_hi))
<< 32);
/* Read the inode. */
if (grub_disk_read (data->disk,
((base + blkno) << LOG2_EXT2_BLOCK_SIZE (data)),
EXT2_INODE_SIZE (data) * blkoff,
sizeof (struct grub_ext2_inode), inode))
return grub_errno;
return 0;
}
static struct grub_ext2_data *
grub_ext2_mount (grub_disk_t disk)
{
struct grub_ext2_data *data;
data = grub_malloc (sizeof (struct grub_ext2_data));
if (!data)
return 0;
/* Read the superblock. */
grub_disk_read (disk, 1 * 2, 0, sizeof (struct grub_ext2_sblock),
&data->sblock);
if (grub_errno)
goto fail;
/* Make sure this is an ext2 filesystem. */
if (data->sblock.magic != grub_cpu_to_le16_compile_time (EXT2_MAGIC)
|| grub_le_to_cpu32 (data->sblock.log2_block_size) >= 16
|| data->sblock.inodes_per_group == 0
/* 20 already means 1GiB blocks. We don't want to deal with blocks overflowing int32. */
|| grub_le_to_cpu32 (data->sblock.log2_block_size) > 20
|| EXT2_INODE_SIZE (data) == 0
|| EXT2_BLOCK_SIZE (data) / EXT2_INODE_SIZE (data) == 0)
{
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 (data->sblock.revision_level != grub_cpu_to_le32_compile_time (EXT2_GOOD_OLD_REVISION)
&& (data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (~(EXT2_DRIVER_SUPPORTED_INCOMPAT
| EXT2_DRIVER_IGNORED_INCOMPAT))))
{
grub_error (GRUB_ERR_BAD_FS, "filesystem has unsupported incompatible features");
goto fail;
}
if (data->sblock.revision_level != grub_cpu_to_le32_compile_time (EXT2_GOOD_OLD_REVISION)
&& (data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (EXT4_FEATURE_INCOMPAT_64BIT))
&& data->sblock.group_desc_size != 0
&& ((data->sblock.group_desc_size & (data->sblock.group_desc_size - 1))
== 0)
&& (data->sblock.group_desc_size & grub_cpu_to_le16_compile_time (0x1fe0)))
{
grub_uint16_t b = grub_le_to_cpu16 (data->sblock.group_desc_size);
for (data->log_group_desc_size = 0; b != (1 << data->log_group_desc_size);
data->log_group_desc_size++);
}
else
data->log_group_desc_size = 5;
data->disk = disk;
data->diropen.data = data;
data->diropen.ino = 2;
data->diropen.inode_read = 1;
data->inode = &data->diropen.inode;
grub_ext2_read_inode (data, 2, data->inode);
if (grub_errno)
goto fail;
return data;
fail:
if (grub_errno == GRUB_ERR_OUT_OF_RANGE)
grub_error (GRUB_ERR_BAD_FS, "not an ext2 filesystem");
grub_free (data);
return 0;
}
static char *
grub_ext2_read_symlink (grub_fshelp_node_t node)
{
char *symlink;
struct grub_fshelp_node *diro = node;
if (! diro->inode_read)
{
grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
if (grub_errno)
return 0;
if (diro->inode.flags & grub_cpu_to_le32_compile_time (EXT4_ENCRYPT_FLAG))
{
grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "symlink is encrypted");
return 0;
}
}
symlink = grub_malloc (grub_le_to_cpu32 (diro->inode.size) + 1);
if (! symlink)
return 0;
/* If the filesize of the symlink is bigger than
60 the symlink is stored in a separate block,
otherwise it is stored in the inode. */
if (grub_le_to_cpu32 (diro->inode.size) <= sizeof (diro->inode.symlink))
grub_memcpy (symlink,
diro->inode.symlink,
grub_le_to_cpu32 (diro->inode.size));
else
{
grub_ext2_read_file (diro, 0, 0, 0,
grub_le_to_cpu32 (diro->inode.size),
symlink);
if (grub_errno)
{
grub_free (symlink);
return 0;
}
}
symlink[grub_le_to_cpu32 (diro->inode.size)] = '\0';
return symlink;
}
static int
grub_ext2_iterate_dir (grub_fshelp_node_t dir,
grub_fshelp_iterate_dir_hook_t hook, void *hook_data)
{
unsigned int fpos = 0;
struct grub_fshelp_node *diro = (struct grub_fshelp_node *) dir;
if (! diro->inode_read)
{
grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
if (grub_errno)
return 0;
}
if (diro->inode.flags & grub_cpu_to_le32_compile_time (EXT4_ENCRYPT_FLAG))
{
grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "directory is encrypted");
return 0;
}
/* Search the file. */
while (fpos < grub_le_to_cpu32 (diro->inode.size))
{
struct ext2_dirent dirent;
grub_ext2_read_file (diro, 0, 0, fpos, sizeof (struct ext2_dirent),
(char *) &dirent);
if (grub_errno)
return 0;
if (dirent.direntlen == 0)
return 0;
if (dirent.inode != 0 && dirent.namelen != 0)
{
char filename[MAX_NAMELEN + 1];
struct grub_fshelp_node *fdiro;
enum grub_fshelp_filetype type = GRUB_FSHELP_UNKNOWN;
grub_ext2_read_file (diro, 0, 0, fpos + sizeof (struct ext2_dirent),
dirent.namelen, filename);
if (grub_errno)
return 0;
fdiro = grub_malloc (sizeof (struct grub_fshelp_node));
if (! fdiro)
return 0;
fdiro->data = diro->data;
fdiro->ino = grub_le_to_cpu32 (dirent.inode);
filename[dirent.namelen] = '\0';
if (dirent.filetype != FILETYPE_UNKNOWN)
{
fdiro->inode_read = 0;
if (dirent.filetype == FILETYPE_DIRECTORY)
type = GRUB_FSHELP_DIR;
else if (dirent.filetype == FILETYPE_SYMLINK)
type = GRUB_FSHELP_SYMLINK;
else if (dirent.filetype == FILETYPE_REG)
type = GRUB_FSHELP_REG;
}
else
{
/* The filetype can not be read from the dirent, read
the inode to get more information. */
grub_ext2_read_inode (diro->data,
grub_le_to_cpu32 (dirent.inode),
&fdiro->inode);
if (grub_errno)
{
grub_free (fdiro);
return 0;
}
fdiro->inode_read = 1;
if ((grub_le_to_cpu16 (fdiro->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY)
type = GRUB_FSHELP_DIR;
else if ((grub_le_to_cpu16 (fdiro->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK)
type = GRUB_FSHELP_SYMLINK;
else if ((grub_le_to_cpu16 (fdiro->inode.mode)
& FILETYPE_INO_MASK) == FILETYPE_INO_REG)
type = GRUB_FSHELP_REG;
}
if (hook (filename, type, fdiro, hook_data))
return 1;
}
fpos += grub_le_to_cpu16 (dirent.direntlen);
}
return 0;
}
/* Open a file named NAME and initialize FILE. */
static grub_err_t
grub_ext2_open (struct grub_file *file, const char *name)
{
struct grub_ext2_data *data;
struct grub_fshelp_node *fdiro = 0;
grub_err_t err;
grub_dl_ref (my_mod);
data = grub_ext2_mount (file->device->disk);
if (! data)
{
err = grub_errno;
goto fail;
}
err = grub_fshelp_find_file (name, &data->diropen, &fdiro,
grub_ext2_iterate_dir,
grub_ext2_read_symlink, GRUB_FSHELP_REG);
if (err)
goto fail;
if (! fdiro->inode_read)
{
err = grub_ext2_read_inode (data, fdiro->ino, &fdiro->inode);
if (err)
goto fail;
}
if (fdiro->inode.flags & grub_cpu_to_le32_compile_time (EXT4_ENCRYPT_FLAG))
{
err = grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "file is encrypted");
goto fail;
}
grub_memcpy (data->inode, &fdiro->inode, sizeof (struct grub_ext2_inode));
grub_free (fdiro);
file->size = grub_le_to_cpu32 (data->inode->size);
file->size |= ((grub_off_t) grub_le_to_cpu32 (data->inode->size_high)) << 32;
file->data = data;
file->offset = 0;
return 0;
fail:
if (fdiro != &data->diropen)
grub_free (fdiro);
grub_free (data);
grub_dl_unref (my_mod);
return err;
}
static grub_err_t
grub_ext2_close (grub_file_t file)
{
grub_free (file->data);
grub_dl_unref (my_mod);
return GRUB_ERR_NONE;
}
/* Read LEN bytes data from FILE into BUF. */
static grub_ssize_t
grub_ext2_read (grub_file_t file, char *buf, grub_size_t len)
{
struct grub_ext2_data *data = (struct grub_ext2_data *) file->data;
return grub_ext2_read_file (&data->diropen,
file->read_hook, file->read_hook_data,
file->offset, len, buf);
}
/* Context for grub_ext2_dir. */
struct grub_ext2_dir_ctx
{
grub_fs_dir_hook_t hook;
void *hook_data;
struct grub_ext2_data *data;
};
/* Helper for grub_ext2_dir. */
static int
grub_ext2_dir_iter (const char *filename, enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node, void *data)
{
struct grub_ext2_dir_ctx *ctx = data;
struct grub_dirhook_info info;
grub_memset (&info, 0, sizeof (info));
if (! node->inode_read)
{
grub_ext2_read_inode (ctx->data, node->ino, &node->inode);
if (!grub_errno)
node->inode_read = 1;
grub_errno = GRUB_ERR_NONE;
}
if (node->inode_read)
{
info.mtimeset = 1;
info.mtime = grub_le_to_cpu32 (node->inode.mtime);
}
info.dir = ((filetype & GRUB_FSHELP_TYPE_MASK) == GRUB_FSHELP_DIR);
grub_free (node);
return ctx->hook (filename, &info, ctx->hook_data);
}
static grub_err_t
grub_ext2_dir (grub_device_t device, const char *path, grub_fs_dir_hook_t hook,
void *hook_data)
{
struct grub_ext2_dir_ctx ctx = {
.hook = hook,
.hook_data = hook_data
};
struct grub_fshelp_node *fdiro = 0;
grub_dl_ref (my_mod);
ctx.data = grub_ext2_mount (device->disk);
if (! ctx.data)
goto fail;
grub_fshelp_find_file (path, &ctx.data->diropen, &fdiro,
grub_ext2_iterate_dir, grub_ext2_read_symlink,
GRUB_FSHELP_DIR);
if (grub_errno)
goto fail;
grub_ext2_iterate_dir (fdiro, grub_ext2_dir_iter, &ctx);
fail:
if (fdiro != &ctx.data->diropen)
grub_free (fdiro);
grub_free (ctx.data);
grub_dl_unref (my_mod);
return grub_errno;
}
static grub_err_t
grub_ext2_label (grub_device_t device, char **label)
{
struct grub_ext2_data *data;
grub_disk_t disk = device->disk;
grub_dl_ref (my_mod);
data = grub_ext2_mount (disk);
if (data)
*label = grub_strndup (data->sblock.volume_name,
sizeof (data->sblock.volume_name));
else
*label = NULL;
grub_dl_unref (my_mod);
grub_free (data);
return grub_errno;
}
static grub_err_t
grub_ext2_uuid (grub_device_t device, char **uuid)
{
struct grub_ext2_data *data;
grub_disk_t disk = device->disk;
grub_dl_ref (my_mod);
data = grub_ext2_mount (disk);
if (data)
{
*uuid = grub_xasprintf ("%04x%04x-%04x-%04x-%04x-%04x%04x%04x",
grub_be_to_cpu16 (data->sblock.uuid[0]),
grub_be_to_cpu16 (data->sblock.uuid[1]),
grub_be_to_cpu16 (data->sblock.uuid[2]),
grub_be_to_cpu16 (data->sblock.uuid[3]),
grub_be_to_cpu16 (data->sblock.uuid[4]),
grub_be_to_cpu16 (data->sblock.uuid[5]),
grub_be_to_cpu16 (data->sblock.uuid[6]),
grub_be_to_cpu16 (data->sblock.uuid[7]));
}
else
*uuid = NULL;
grub_dl_unref (my_mod);
grub_free (data);
return grub_errno;
}
/* Get mtime. */
static grub_err_t
grub_ext2_mtime (grub_device_t device, grub_int32_t *tm)
{
struct grub_ext2_data *data;
grub_disk_t disk = device->disk;
grub_dl_ref (my_mod);
data = grub_ext2_mount (disk);
if (!data)
*tm = 0;
else
*tm = grub_le_to_cpu32 (data->sblock.utime);
grub_dl_unref (my_mod);
grub_free (data);
return grub_errno;
}
static struct grub_fs grub_ext2_fs =
{
.name = "ext2",
.dir = grub_ext2_dir,
.open = grub_ext2_open,
.read = grub_ext2_read,
.close = grub_ext2_close,
.label = grub_ext2_label,
.uuid = grub_ext2_uuid,
.mtime = grub_ext2_mtime,
#ifdef GRUB_UTIL
.reserved_first_sector = 1,
.blocklist_install = 1,
#endif
.next = 0
};
GRUB_MOD_INIT(ext2)
{
grub_fs_register (&grub_ext2_fs);
my_mod = mod;
}
GRUB_MOD_FINI(ext2)
{
grub_fs_unregister (&grub_ext2_fs);
}
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