Provide a field in the block group descriptor to store inode bitmap checksum,
and some helper functions to calculate and verify it.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
lib/ext2fs/blknum.c | 11 +++++++++++
lib/ext2fs/closefs.c | 29 +++++++++++++++++------------
lib/ext2fs/csum.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
lib/ext2fs/ext2_fs.h | 3 ++-
lib/ext2fs/ext2fs.h | 7 +++++++
lib/ext2fs/rw_bitmaps.c | 15 +++++++++++++++
lib/ext2fs/swapfs.c | 1 +
7 files changed, 98 insertions(+), 13 deletions(-)
diff --git a/lib/ext2fs/blknum.c b/lib/ext2fs/blknum.c
index 7e7fcd8..47d3fda 100644
--- a/lib/ext2fs/blknum.c
+++ b/lib/ext2fs/blknum.c
@@ -210,6 +210,17 @@ void ext2fs_block_bitmap_loc_set(ext2_filsys fs, dgrp_t group, blk64_t blk)
}
/*
+ * Return the inode bitmap checksum of a group
+ */
+blk64_t ext2fs_inode_bitmap_checksum(ext2_filsys fs, dgrp_t group)
+{
+ struct ext4_group_desc *gdp;
+
+ gdp = ext4fs_group_desc(fs, fs->group_desc, group);
+ return gdp->bg_inode_bitmap_csum;
+}
+
+/*
* Return the inode bitmap block of a group
*/
blk64_t ext2fs_inode_bitmap_loc(ext2_filsys fs, dgrp_t group)
diff --git a/lib/ext2fs/closefs.c b/lib/ext2fs/closefs.c
index 952f496..73dc136 100644
--- a/lib/ext2fs/closefs.c
+++ b/lib/ext2fs/closefs.c
@@ -289,6 +289,23 @@ errcode_t ext2fs_flush(ext2_filsys fs)
fs->super->s_wtime = fs->now ? fs->now : time(NULL);
fs->super->s_block_group_nr = 0;
+
+ /*
+ * If the write_bitmaps() function is present, call it to
+ * flush the bitmaps. This is done this way so that a simple
+ * program that doesn't mess with the bitmaps doesn't need to
+ * drag in the bitmaps.c code.
+ *
+ * Bitmap checksums live in the group descriptor, so the
+ * bitmaps need to be written before the descriptors.
+ */
+ if (fs->write_bitmaps) {
+ retval = fs->write_bitmaps(fs);
+ if (retval)
+ goto errout;
+ }
+
+ /* Prepare the group descriptors for writing */
#ifdef WORDS_BIGENDIAN
retval = EXT2_ET_NO_MEMORY;
retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
@@ -379,18 +396,6 @@ errcode_t ext2fs_flush(ext2_filsys fs)
ext2fs_numeric_progress_close(fs, &progress, NULL);
- /*
- * If the write_bitmaps() function is present, call it to
- * flush the bitmaps. This is done this way so that a simple
- * program that doesn't mess with the bitmaps doesn't need to
- * drag in the bitmaps.c code.
- */
- if (fs->write_bitmaps) {
- retval = fs->write_bitmaps(fs);
- if (retval)
- goto errout;
- }
-
write_primary_superblock_only:
/*
* Write out master superblock. This has to be done
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 57adc4c..56b75da 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -29,6 +29,51 @@
#define STATIC static
#endif
+__u32 ext2fs_bitmap_csum(ext2_filsys fs, dgrp_t group, char *bitmap, int size)
+{
+ __u32 crc = 0;
+
+ if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT)
+ return 0;
+
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 0;
+
+ group = ext2fs_cpu_to_le32(group);
+ crc = crc32c_le(~0, fs->super->s_uuid, sizeof(fs->super->s_uuid));
+ crc = crc32c_le(crc, (char *)&group, sizeof(group));
+ crc = crc32c_le(crc, (char *)bitmap, size);
+
+ return crc;
+}
+
+int ext2fs_bitmap_csum_verify(ext2_filsys fs, dgrp_t group, __u32 provided,
+ char *bitmap, int size)
+{
+ if (fs->super->s_desc_size >= EXT2_MIN_DESC_SIZE_64BIT &&
+ EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+ (provided != ext2fs_bitmap_csum(fs, group, bitmap, size)))
+ return 0;
+ return 1;
+}
+
+void ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group, char *bitmap,
+ int size)
+{
+ struct ext4_group_desc *gdp = (struct ext4_group_desc *)
+ ext2fs_group_desc(fs, fs->group_desc, group);
+
+ if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT)
+ return;
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return;
+
+ gdp->bg_inode_bitmap_csum = ext2fs_bitmap_csum(fs, group, bitmap, size);
+}
+
__u32 ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
struct ext2_inode_large *inode)
{
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 1f08673..367bfdf 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -169,7 +169,8 @@ struct ext4_group_desc
__u16 bg_free_inodes_count_hi;/* Free inodes count MSB */
__u16 bg_used_dirs_count_hi; /* Directories count MSB */
__u16 bg_itable_unused_hi; /* Unused inodes count MSB */
- __u32 bg_reserved2[3];
+ __u32 bg_inode_bitmap_csum; /* crc32c(uuid+group+ibitmap) */
+ __u32 bg_reserved2[2];
};
#define EXT2_BG_INODE_UNINIT 0x0001 /* Inode table/bitmap not initialized */
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index db8b28b..0899e34 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -785,6 +785,7 @@ extern struct ext2_group_desc *ext2fs_group_desc(ext2_filsys fs,
extern blk64_t ext2fs_block_bitmap_loc(ext2_filsys fs, dgrp_t group);
extern void ext2fs_block_bitmap_loc_set(ext2_filsys fs, dgrp_t group,
blk64_t blk);
+extern blk64_t ext2fs_inode_bitmap_csum(ext2_filsys fs, dgrp_t group);
extern blk64_t ext2fs_inode_bitmap_loc(ext2_filsys fs, dgrp_t group);
extern void ext2fs_inode_bitmap_loc_set(ext2_filsys fs, dgrp_t group,
blk64_t blk);
@@ -892,6 +893,12 @@ extern __u32 crc32c_be(__u32 crc, unsigned char const *p, size_t len);
extern __u32 crc32c_le(__u32 crc, unsigned char const *p, size_t len);
/* csum.c */
+extern __u32 ext2fs_bitmap_csum(ext2_filsys fs, dgrp_t group, char *bitmap,
+ int size);
+extern int ext2fs_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
+ __u32 provided, char *bitmap, int size);
+extern void ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
+ char *bitmap, int size);
extern __u32 ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
struct ext2_inode_large *inode);
extern void ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c
index f8c8a9f..57aba59 100644
--- a/lib/ext2fs/rw_bitmaps.c
+++ b/lib/ext2fs/rw_bitmaps.c
@@ -114,6 +114,9 @@ static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
if (retval)
return retval;
+ ext2fs_inode_bitmap_csum_set(fs, i, inode_buf, inode_nbytes);
+ ext2fs_group_desc_csum_set(fs, i);
+
blk = ext2fs_inode_bitmap_loc(fs, i);
if (blk) {
retval = io_channel_write_blk64(fs->io, blk, 1,
@@ -152,6 +155,7 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
blk64_t blk_cnt;
ext2_ino_t ino_itr = 1;
ext2_ino_t ino_cnt;
+ struct ext4_group_desc *gdp;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
@@ -277,6 +281,17 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
retval = EXT2_ET_INODE_BITMAP_READ;
goto cleanup;
}
+
+ /* verify inode bitmap checksum */
+ gdp = (struct ext4_group_desc *)
+ ext2fs_group_desc(fs, fs->group_desc,
+ i);
+ if (!(fs->flags &
+ EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_bitmap_csum_verify(fs, i,
+ gdp->bg_inode_bitmap_csum,
+ inode_bitmap, inode_nbytes))
+ return EXT2_ET_INODE_BITMAP_READ;
} else
memset(inode_bitmap, 0, inode_nbytes);
cnt = inode_nbytes << 3;
diff --git a/lib/ext2fs/swapfs.c b/lib/ext2fs/swapfs.c
index df604ba..747e130 100644
--- a/lib/ext2fs/swapfs.c
+++ b/lib/ext2fs/swapfs.c
@@ -125,6 +125,7 @@ void ext2fs_swap_group_desc2(ext2_filsys fs, struct ext2_group_desc *gdp)
gdp4->bg_used_dirs_count_hi =
ext2fs_swab16(gdp4->bg_used_dirs_count_hi);
gdp4->bg_itable_unused_hi = ext2fs_swab16(gdp4->bg_itable_unused_hi);
+ gdp4->bg_inode_bitmap_csum = ext2fs_swab32(gdp4->bg_inode_bitmap_csum);
}
void ext2fs_swap_group_desc(struct ext2_group_desc *gdp)
--
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