Calculate and verify the checksum for separate (i.e. not in the inode) extended
attribute blocks; the checksum lives in the header.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
lib/ext2fs/csum.c | 54 ++++++++++++++++++++++++++++++++++++++++++++
lib/ext2fs/ext2_err.et.in | 3 ++
lib/ext2fs/ext2_ext_attr.h | 3 ++
lib/ext2fs/ext2fs.h | 6 +++++
lib/ext2fs/ext_attr.c | 11 ++++++++-
lib/ext2fs/swapfs.c | 3 ++
6 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index a606b7c..4fe4b3d 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -29,6 +29,60 @@
#define STATIC static
#endif
+__u32 ext2fs_ext_attr_block_csum(ext2_filsys fs, blk64_t block,
+ struct ext2_ext_attr_header *hdr)
+{
+ char *buf = (char *)hdr;
+ int offset = offsetof(struct ext2_ext_attr_header, h_checksum);
+ __u32 crc = 0;
+
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 0;
+
+#ifdef WORDS_BIGENDIAN
+ errcode_t retval;
+
+ retval = ext2fs_get_mem(fs->blocksize, &buf);
+ if (retval)
+ return retval;
+ ext2fs_swap_ext_attr(buf, (char *)hdr, fs->blocksize, 1);
+#endif
+
+ block = ext2fs_cpu_to_le64(block);
+ crc = crc32c_le(~0, fs->super->s_uuid, sizeof(fs->super->s_uuid));
+ crc = crc32c_le(crc, (char *)&block, sizeof(block));
+ crc = crc32c_le(crc, buf, offset);
+ offset += sizeof(hdr->h_checksum); /* skip checksum */
+ crc = crc32c_le(crc, buf + offset, fs->blocksize - offset);
+
+#ifdef WORDS_BIGENDIAN
+ ext2fs_free_mem(&buf);
+#endif
+
+ return crc;
+}
+
+int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, blk64_t block,
+ struct ext2_ext_attr_header *hdr)
+{
+ if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+ (hdr->h_checksum != ext2fs_ext_attr_block_csum(fs, block, hdr)))
+ return 0;
+ return 1;
+}
+
+void ext2fs_ext_attr_block_csum_set(ext2_filsys fs, blk64_t block,
+ struct ext2_ext_attr_header *hdr)
+{
+ if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return;
+
+ hdr->h_checksum = ext2fs_ext_attr_block_csum(fs, block, hdr);
+}
+
static struct ext2_dir_entry_tail *get_dirent_tail(ext2_filsys fs,
struct ext2_dir_entry *dirent)
{
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index 31c8fe1..6e2c22c 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -431,4 +431,7 @@ ec EXT2_ET_INODE_CORRUPT,
ec EXT2_ET_INODE_CSUM_NONZERO,
"Inode checksum should not be set"
+ec EXT2_ET_EXT_ATTR_BLOCK_CORRUPT,
+ "Extended attribute block fails checksum"
+
end
diff --git a/lib/ext2fs/ext2_ext_attr.h b/lib/ext2fs/ext2_ext_attr.h
index ed548d1..ee45175 100644
--- a/lib/ext2fs/ext2_ext_attr.h
+++ b/lib/ext2fs/ext2_ext_attr.h
@@ -20,7 +20,8 @@ struct ext2_ext_attr_header {
__u32 h_refcount; /* reference count */
__u32 h_blocks; /* number of disk blocks used */
__u32 h_hash; /* hash value of all attributes */
- __u32 h_reserved[4]; /* zero right now */
+ __u32 h_checksum; /* crc32c(uuid+inode+xattrs) */
+ __u32 h_reserved[3]; /* zero right now */
};
struct ext2_ext_attr_entry {
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 706357a..0820e43 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -894,6 +894,12 @@ 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_ext_attr_block_csum(ext2_filsys fs, blk64_t block,
+ struct ext2_ext_attr_header *hdr);
+extern int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, blk64_t block,
+ struct ext2_ext_attr_header *hdr);
+extern void ext2fs_ext_attr_block_csum_set(ext2_filsys fs, blk64_t block,
+ struct ext2_ext_attr_header *hdr);
extern int ext2fs_dirent_has_tail(ext2_filsys fs,
struct ext2_dir_entry *dirent);
extern int ext2fs_dir_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
index 52664eb..2240e3e 100644
--- a/lib/ext2fs/ext_attr.c
+++ b/lib/ext2fs/ext_attr.c
@@ -70,6 +70,11 @@ errcode_t ext2fs_read_ext_attr2(ext2_filsys fs, blk64_t block, void *buf)
#ifdef WORDS_BIGENDIAN
ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
#endif
+
+ if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+ !ext2fs_ext_attr_block_csum_verify(fs, block, buf))
+ return EXT2_ET_EXT_ATTR_BLOCK_CORRUPT;
+
return 0;
}
@@ -84,6 +89,9 @@ errcode_t ext2fs_write_ext_attr2(ext2_filsys fs, blk64_t block, void *inbuf)
char *write_buf;
char *buf = NULL;
+ ext2fs_ext_attr_block_csum_set(fs, block,
+ (struct ext2_ext_attr_header *)inbuf);
+
#ifdef WORDS_BIGENDIAN
retval = ext2fs_get_mem(fs->blocksize, &buf);
if (retval)
@@ -151,5 +159,6 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
char *block_buf, int adjust,
__u32 *newcount)
{
- return ext2fs_adjust_ea_refcount(fs, blk, block_buf, adjust, newcount);
+ return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust,
+ newcount);
}
diff --git a/lib/ext2fs/swapfs.c b/lib/ext2fs/swapfs.c
index 570ab7d..a13f46a 100644
--- a/lib/ext2fs/swapfs.c
+++ b/lib/ext2fs/swapfs.c
@@ -144,7 +144,8 @@ void ext2fs_swap_ext_attr_header(struct ext2_ext_attr_header *to_header,
to_header->h_blocks = ext2fs_swab32(from_header->h_blocks);
to_header->h_refcount = ext2fs_swab32(from_header->h_refcount);
to_header->h_hash = ext2fs_swab32(from_header->h_hash);
- for (n = 0; n < 4; n++)
+ to_header->h_checksum = ext2fs_swab32(from_header->h_checksum);
+ for (n = 0; n < 3; n++)
to_header->h_reserved[n] =
ext2fs_swab32(from_header->h_reserved[n]);
}
--
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