Calculate and verify the checksums for directory leaf blocks (i.e. blocks that
only contain actual directory entries). The checksum lives in what looks to be
an unused directory entry with a 0 name_len at the end of the block. This
scheme is not used for internal htree nodes because the mechanism in place
there only costs one dx_entry, whereas the "empty" directory entry would cost
two dx_entries.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/ext4/dir.c | 12 +++
fs/ext4/ext4.h | 2
fs/ext4/namei.c | 260 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
3 files changed, 259 insertions(+), 15 deletions(-)
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 164c560..bc40c9e 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -180,6 +180,18 @@ static int ext4_readdir(struct file *filp,
continue;
}
+ /* Check the checksum */
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(inode,
+ (struct ext4_dir_entry *)bh->b_data)) {
+ EXT4_ERROR_FILE(filp, 0, "directory fails checksum "
+ "at offset %llu",
+ (unsigned long long)filp->f_pos);
+ filp->f_pos += sb->s_blocksize - offset;
+ continue;
+ }
+ set_buffer_verified(bh);
+
revalidate:
/* If the dir block has changed since the last call to
* readdir(2), then we might be pointing to an invalid
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9d99b16..fff5245 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2000,6 +2000,8 @@ extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
extern int ext4_ext_migrate(struct inode *);
/* namei.c */
+extern int ext4_dirent_csum_verify(struct inode *inode,
+ struct ext4_dir_entry *dirent);
extern int ext4_orphan_add(handle_t *, struct inode *);
extern int ext4_orphan_del(handle_t *, struct inode *);
extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 064ae7c..87b6dbe 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -189,6 +189,115 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
struct inode *inode);
/* checksumming functions */
+#define EXT4_DIRENT_TAIL(block, blocksize) \
+ ((struct ext4_dir_entry_tail *)(((void *)(block)) + \
+ ((blocksize) - \
+ sizeof(struct ext4_dir_entry_tail))))
+
+static void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
+ unsigned int blocksize)
+{
+ memset(t, 0, sizeof(struct ext4_dir_entry_tail));
+ t->det_rec_len = ext4_rec_len_to_disk(
+ sizeof(struct ext4_dir_entry_tail), blocksize);
+ t->det_reserved_ft = EXT4_FT_DIR_CSUM;
+}
+
+/* Walk through a dirent block to find a checksum "dirent" at the tail */
+static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
+ struct ext4_dir_entry *de)
+{
+ struct ext4_dir_entry_tail *t;
+
+#ifdef PARANOID
+ struct ext4_dir_entry *d, *top;
+
+ d = de;
+ top = (struct ext4_dir_entry *)(((void *)de) +
+ (EXT4_BLOCK_SIZE(inode->i_sb) -
+ sizeof(struct ext4_dir_entry_tail)));
+ while (d < top && d->rec_len)
+ d = (struct ext4_dir_entry *)(((void *)d) +
+ le16_to_cpu(d->rec_len));
+
+ if (d != top)
+ return NULL;
+
+ t = (struct ext4_dir_entry_tail *)d;
+#else
+ t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
+#endif
+
+ if (t->det_reserved_zero1 ||
+ le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
+ t->det_reserved_zero2 ||
+ t->det_reserved_ft != EXT4_FT_DIR_CSUM)
+ return NULL;
+
+ return t;
+}
+
+static __le32 ext4_dirent_csum(struct inode *inode,
+ struct ext4_dir_entry *dirent, int size)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ __u32 csum;
+
+ csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
+ return cpu_to_le32(csum);
+}
+
+int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
+{
+ struct ext4_dir_entry_tail *t;
+
+ if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return 1;
+
+ t = get_dirent_tail(inode, dirent);
+ if (!t) {
+ EXT4_ERROR_INODE(inode, "metadata_csum set but no space in dir "
+ "leaf for checksum. Please run e2fsck -D.");
+ return 0;
+ }
+
+ if (t->det_checksum != ext4_dirent_csum(inode, dirent,
+ (void *)t - (void *)dirent))
+ return 0;
+
+ return 1;
+}
+
+static void ext4_dirent_csum_set(struct inode *inode,
+ struct ext4_dir_entry *dirent)
+{
+ struct ext4_dir_entry_tail *t;
+
+ if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return;
+
+ t = get_dirent_tail(inode, dirent);
+ if (!t) {
+ EXT4_ERROR_INODE(inode, "metadata_csum set but no space in dir "
+ "leaf for checksum. Please run e2fsck -D.");
+ return;
+ }
+
+ t->det_checksum = ext4_dirent_csum(inode, dirent,
+ (void *)t - (void *)dirent);
+}
+
+static inline int ext4_handle_dirty_dirent_node(handle_t *handle,
+ struct inode *inode,
+ struct buffer_head *bh)
+{
+ ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
+ return ext4_handle_dirty_metadata(handle, inode, bh);
+}
+
static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
struct ext4_dir_entry *dirent,
int *offset)
@@ -737,6 +846,11 @@ static int htree_dirblock_to_tree(struct file *dir_file,
if (!(bh = ext4_bread (NULL, dir, block, 0, &err)))
return err;
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data))
+ return -EIO;
+ set_buffer_verified(bh);
+
de = (struct ext4_dir_entry_2 *) bh->b_data;
top = (struct ext4_dir_entry_2 *) ((char *) de +
dir->i_sb->s_blocksize -
@@ -1096,6 +1210,15 @@ restart:
brelse(bh);
goto next;
}
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(dir,
+ (struct ext4_dir_entry *)bh->b_data)) {
+ EXT4_ERROR_INODE(dir, "checksumming directory "
+ "block %lu", (unsigned long)block);
+ brelse(bh);
+ goto next;
+ }
+ set_buffer_verified(bh);
i = search_dirblock(bh, dir, d_name,
block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
if (i == 1) {
@@ -1147,6 +1270,16 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct q
if (!(bh = ext4_bread(NULL, dir, block, 0, err)))
goto errout;
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(dir,
+ (struct ext4_dir_entry *)bh->b_data)) {
+ EXT4_ERROR_INODE(dir, "checksumming directory "
+ "block %lu", (unsigned long)block);
+ brelse(bh);
+ *err = -EIO;
+ goto errout;
+ }
+ set_buffer_verified(bh);
retval = search_dirblock(bh, dir, d_name,
block << EXT4_BLOCK_SIZE_BITS(sb),
res_dir);
@@ -1319,8 +1452,14 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
char *data1 = (*bh)->b_data, *data2;
unsigned split, move, size;
struct ext4_dir_entry_2 *de = NULL, *de2;
+ struct ext4_dir_entry_tail *t;
+ int csum_size = 0;
int err = 0, i;
+ if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
+
bh2 = ext4_append (handle, dir, &newblock, &err);
if (!(bh2)) {
brelse(*bh);
@@ -1367,10 +1506,20 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
/* Fancy dance to stay within two buffers */
de2 = dx_move_dirents(data1, data2, map + split, count - split, blocksize);
de = dx_pack_dirents(data1, blocksize);
- de->rec_len = ext4_rec_len_to_disk(data1 + blocksize - (char *) de,
+ de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
+ (char *) de,
blocksize);
- de2->rec_len = ext4_rec_len_to_disk(data2 + blocksize - (char *) de2,
+ de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
+ (char *) de2,
blocksize);
+ if (csum_size) {
+ t = EXT4_DIRENT_TAIL(data2, blocksize);
+ initialize_dirent_tail(t, blocksize);
+
+ t = EXT4_DIRENT_TAIL(data1, blocksize);
+ initialize_dirent_tail(t, blocksize);
+ }
+
dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
@@ -1381,7 +1530,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
de = de2;
}
dx_insert_block(frame, hash2 + continued, newblock);
- err = ext4_handle_dirty_metadata(handle, dir, bh2);
+ err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
if (err)
goto journal_error;
err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
@@ -1421,11 +1570,16 @@ static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
unsigned short reclen;
int nlen, rlen, err;
char *top;
+ int csum_size = 0;
+
+ if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
reclen = EXT4_DIR_REC_LEN(namelen);
if (!de) {
de = (struct ext4_dir_entry_2 *)bh->b_data;
- top = bh->b_data + blocksize - reclen;
+ top = bh->b_data + (blocksize - csum_size) - reclen;
while ((char *) de <= top) {
if (ext4_check_dir_entry(dir, NULL, de, bh, offset))
return -EIO;
@@ -1481,7 +1635,7 @@ static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
dir->i_version++;
ext4_mark_inode_dirty(handle, dir);
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, dir, bh);
+ err = ext4_handle_dirty_dirent_node(handle, dir, bh);
if (err)
ext4_std_error(dir->i_sb, err);
return 0;
@@ -1502,6 +1656,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
struct dx_frame frames[2], *frame;
struct dx_entry *entries;
struct ext4_dir_entry_2 *de, *de2;
+ struct ext4_dir_entry_tail *t;
char *data1, *top;
unsigned len;
int retval;
@@ -1509,6 +1664,11 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
struct dx_hash_info hinfo;
ext4_lblk_t block;
struct fake_dirent *fde;
+ int csum_size = 0;
+
+ if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
blocksize = dir->i_sb->s_blocksize;
dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
@@ -1529,7 +1689,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
brelse(bh);
return -EIO;
}
- len = ((char *) root) + blocksize - (char *) de;
+ len = ((char *) root) + (blocksize - csum_size) - (char *) de;
/* Allocate new block for the 0th block's dirents */
bh2 = ext4_append(handle, dir, &block, &retval);
@@ -1545,8 +1705,15 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
top = data1 + len;
while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
de = de2;
- de->rec_len = ext4_rec_len_to_disk(data1 + blocksize - (char *) de,
+ de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
+ (char *) de,
blocksize);
+
+ if (csum_size) {
+ t = EXT4_DIRENT_TAIL(data1, blocksize);
+ initialize_dirent_tail(t, blocksize);
+ }
+
/* Initialize the root; the dot dirents already exist */
de = (struct ext4_dir_entry_2 *) (&root->dotdot);
de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
@@ -1572,7 +1739,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
bh = bh2;
ext4_handle_dirty_dx_node(handle, dir, frame->bh);
- ext4_handle_dirty_metadata(handle, dir, bh);
+ ext4_handle_dirty_dirent_node(handle, dir, bh);
de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
if (!de) {
@@ -1608,11 +1775,17 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
struct inode *dir = dentry->d_parent->d_inode;
struct buffer_head *bh;
struct ext4_dir_entry_2 *de;
+ struct ext4_dir_entry_tail *t;
struct super_block *sb;
int retval;
int dx_fallback=0;
unsigned blocksize;
ext4_lblk_t block, blocks;
+ int csum_size = 0;
+
+ if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
sb = dir->i_sb;
blocksize = sb->s_blocksize;
@@ -1631,6 +1804,11 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
bh = ext4_bread(handle, dir, block, 0, &retval);
if(!bh)
return retval;
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(dir,
+ (struct ext4_dir_entry *)bh->b_data))
+ return -EIO;
+ set_buffer_verified(bh);
retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
if (retval != -ENOSPC) {
brelse(bh);
@@ -1647,7 +1825,13 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
return retval;
de = (struct ext4_dir_entry_2 *) bh->b_data;
de->inode = 0;
- de->rec_len = ext4_rec_len_to_disk(blocksize, blocksize);
+ de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
+
+ if (csum_size) {
+ t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
+ initialize_dirent_tail(t, blocksize);
+ }
+
retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
brelse(bh);
if (retval == 0)
@@ -1679,6 +1863,11 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
if (!(bh = ext4_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
goto cleanup;
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data))
+ goto journal_error;
+ set_buffer_verified(bh);
+
BUFFER_TRACE(bh, "get_write_access");
err = ext4_journal_get_write_access(handle, bh);
if (err)
@@ -1804,12 +1993,17 @@ static int ext4_delete_entry(handle_t *handle,
{
struct ext4_dir_entry_2 *de, *pde;
unsigned int blocksize = dir->i_sb->s_blocksize;
+ int csum_size = 0;
int i, err;
+ if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
+
i = 0;
pde = NULL;
de = (struct ext4_dir_entry_2 *) bh->b_data;
- while (i < bh->b_size) {
+ while (i < bh->b_size - csum_size) {
if (ext4_check_dir_entry(dir, NULL, de, bh, i))
return -EIO;
if (de == de_del) {
@@ -1830,7 +2024,7 @@ static int ext4_delete_entry(handle_t *handle,
de->inode = 0;
dir->i_version++;
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, dir, bh);
+ err = ext4_handle_dirty_dirent_node(handle, dir, bh);
if (unlikely(err)) {
ext4_std_error(dir->i_sb, err);
return err;
@@ -1972,9 +2166,15 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
struct inode *inode;
struct buffer_head *dir_block = NULL;
struct ext4_dir_entry_2 *de;
+ struct ext4_dir_entry_tail *t;
unsigned int blocksize = dir->i_sb->s_blocksize;
+ int csum_size = 0;
int err, retries = 0;
+ if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
+
if (EXT4_DIR_LINK_MAX(dir))
return -EMLINK;
@@ -2015,16 +2215,24 @@ retry:
ext4_set_de_type(dir->i_sb, de, S_IFDIR);
de = ext4_next_entry(de, blocksize);
de->inode = cpu_to_le32(dir->i_ino);
- de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(1),
+ de->rec_len = ext4_rec_len_to_disk(blocksize -
+ (csum_size + EXT4_DIR_REC_LEN(1)),
blocksize);
de->name_len = 2;
strcpy(de->name, "..");
ext4_set_de_type(dir->i_sb, de, S_IFDIR);
set_nlink(inode, 2);
+
+ if (csum_size) {
+ t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
+ initialize_dirent_tail(t, blocksize);
+ }
+
BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, inode, dir_block);
+ err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
if (err)
goto out_clear_inode;
+ set_buffer_verified(dir_block);
err = ext4_mark_inode_dirty(handle, inode);
if (!err)
err = ext4_add_entry(handle, dentry, inode);
@@ -2074,6 +2282,14 @@ static int empty_dir(struct inode *inode)
inode->i_ino);
return 1;
}
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(inode,
+ (struct ext4_dir_entry *)bh->b_data)) {
+ EXT4_ERROR_INODE(inode, "checksum error reading directory "
+ "lblock 0");
+ return -EIO;
+ }
+ set_buffer_verified(bh);
de = (struct ext4_dir_entry_2 *) bh->b_data;
de1 = ext4_next_entry(de, sb->s_blocksize);
if (le32_to_cpu(de->inode) != inode->i_ino ||
@@ -2105,6 +2321,14 @@ static int empty_dir(struct inode *inode)
offset += sb->s_blocksize;
continue;
}
+ if (!buffer_verified(bh) &&
+ !ext4_dirent_csum_verify(inode,
+ (struct ext4_dir_entry *)bh->b_data)) {
+ EXT4_ERROR_INODE(inode, "checksum error "
+ "reading directory lblock 0");
+ return -EIO;
+ }
+ set_buffer_verified(bh);
de = (struct ext4_dir_entry_2 *) bh->b_data;
}
if (ext4_check_dir_entry(inode, NULL, de, bh, offset)) {
@@ -2605,6 +2829,11 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
dir_bh = ext4_bread(handle, old_inode, 0, 0, &retval);
if (!dir_bh)
goto end_rename;
+ if (!buffer_verified(dir_bh) &&
+ !ext4_dirent_csum_verify(old_inode,
+ (struct ext4_dir_entry *)dir_bh->b_data))
+ goto end_rename;
+ set_buffer_verified(dir_bh);
if (le32_to_cpu(PARENT_INO(dir_bh->b_data,
old_dir->i_sb->s_blocksize)) != old_dir->i_ino)
goto end_rename;
@@ -2635,7 +2864,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
ext4_current_time(new_dir);
ext4_mark_inode_dirty(handle, new_dir);
BUFFER_TRACE(new_bh, "call ext4_handle_dirty_metadata");
- retval = ext4_handle_dirty_metadata(handle, new_dir, new_bh);
+ retval = ext4_handle_dirty_dirent_node(handle, new_dir, new_bh);
if (unlikely(retval)) {
ext4_std_error(new_dir->i_sb, retval);
goto end_rename;
@@ -2689,7 +2918,8 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
PARENT_INO(dir_bh->b_data, new_dir->i_sb->s_blocksize) =
cpu_to_le32(new_dir->i_ino);
BUFFER_TRACE(dir_bh, "call ext4_handle_dirty_metadata");
- retval = ext4_handle_dirty_metadata(handle, old_inode, dir_bh);
+ retval = ext4_handle_dirty_dirent_node(handle, old_inode,
+ dir_bh);
if (retval) {
ext4_std_error(old_dir->i_sb, retval);
goto end_rename;
--
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