return 0;
}
+static bool is_fake_dir_entry(struct ext4_dir_entry_2 *de)
+{
+ /* Check if . or .. , or skip if namelen is 0 */
+ if ((de->name_len > 0) && (de->name_len <= 2) && (de->name[0] == '.') &&
+ (de->name[1] == '.' || de->name[1] == '\0'))
+ return true;
+ /* Check if this is a csum entry */
+ if (de->file_type == EXT4_FT_DIR_CSUM)
+ return true;
+ return false;
+}
+
/*
* Return 0 if the directory entry is OK, and 1 if there is a problem
*
const int rlen = ext4_rec_len_from_disk(de->rec_len,
dir->i_sb->s_blocksize);
const int next_offset = ((char *) de - buf) + rlen;
+ bool fake = is_fake_dir_entry(de);
+ bool has_csum = ext4_has_metadata_csum(dir->i_sb);
- if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
+ if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir)))
error_msg = "rec_len is smaller than minimal";
else if (unlikely(rlen % 4 != 0))
error_msg = "rec_len % 4 != 0";
- else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
+ else if (unlikely(rlen < ext4_dir_rec_len(de->name_len,
+ fake ? NULL : dir)))
error_msg = "rec_len is too small for name_len";
else if (unlikely(next_offset > size))
error_msg = "directory entry overrun";
- else if (unlikely(next_offset > size - EXT4_DIR_REC_LEN(1) &&
+ else if (unlikely(next_offset > size - ext4_dir_rec_len(1,
+ has_csum ? NULL : dir) &&
next_offset != size))
error_msg = "directory entry too close to block end";
else if (unlikely(le32_to_cpu(de->inode) >
if (filp)
ext4_error_file(filp, function, line, bh->b_blocknr,
"bad entry in directory: %s - offset=%u, "
- "inode=%u, rec_len=%d, name_len=%d, size=%d",
+ "inode=%u, rec_len=%d, size=%d fake=%d",
error_msg, offset, le32_to_cpu(de->inode),
- rlen, de->name_len, size);
+ rlen, size, fake);
else
ext4_error_inode(dir, function, line, bh->b_blocknr,
"bad entry in directory: %s - offset=%u, "
- "inode=%u, rec_len=%d, name_len=%d, size=%d",
+ "inode=%u, rec_len=%d, size=%d fake=%d",
error_msg, offset, le32_to_cpu(de->inode),
- rlen, de->name_len, size);
+ rlen, size, fake);
return 1;
}
* failure will be detected in the
* dirent test below. */
if (ext4_rec_len_from_disk(de->rec_len,
- sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
+ sb->s_blocksize) < ext4_dir_rec_len(1,
+ inode))
break;
i += ext4_rec_len_from_disk(de->rec_len,
sb->s_blocksize);
/* Directory is encrypted */
err = fscrypt_fname_disk_to_usr(inode,
- 0, 0, &de_name, &fstr);
+ EXT4_DIRENT_HASH(de),
+ EXT4_DIRENT_MINOR_HASH(de),
+ &de_name, &fstr);
de_name = fstr;
fstr.len = save_len;
if (err)
char name[EXT4_NAME_LEN]; /* File name */
};
+
+/*
+ * Encrypted Casefolded entries require saving the hash on disk. This structure
+ * followed ext4_dir_entry_2's name[name_len] at the next 4 byte aligned
+ * boundary.
+ */
+struct ext4_dir_entry_hash {
+ __le32 hash;
+ __le32 minor_hash;
+};
+
/*
* The new version of the directory entry. Since EXT4 structures are
* stored in intel byte order, and the name_len field could never be
char name[EXT4_NAME_LEN]; /* File name */
};
+/*
+ * Access the hashes at the end of ext4_dir_entry_2
+ */
+#define EXT4_DIRENT_HASHES(entry) \
+ ((struct ext4_dir_entry_hash *) \
+ (((void *)(entry)) + \
+ ((8 + (entry)->name_len + EXT4_DIR_ROUND) & ~EXT4_DIR_ROUND)))
+#define EXT4_DIRENT_HASH(entry) le32_to_cpu(EXT4_DIRENT_HASHES(de)->hash)
+#define EXT4_DIRENT_MINOR_HASH(entry) \
+ le32_to_cpu(EXT4_DIRENT_HASHES(de)->minor_hash)
+
+static inline bool ext4_hash_in_dirent(const struct inode *inode)
+{
+ return IS_CASEFOLDED(inode) && IS_ENCRYPTED(inode);
+}
+
/*
* This is a bogus directory entry at the end of each leaf block that
* records checksums.
*/
#define EXT4_DIR_PAD 4
#define EXT4_DIR_ROUND (EXT4_DIR_PAD - 1)
-#define EXT4_DIR_REC_LEN(name_len) (((name_len) + 8 + EXT4_DIR_ROUND) & \
- ~EXT4_DIR_ROUND)
#define EXT4_MAX_REC_LEN ((1<<16)-1)
+/*
+ * The rec_len is dependent on the type of directory. Directories that are
+ * casefolded and encrypted need to store the hash as well, so we add room for
+ * ext4_extended_dir_entry_2. For all entries related to '.' or '..' you should
+ * pass NULL for dir, as those entries do not use the extra fields.
+ */
+static inline unsigned int ext4_dir_rec_len(__u8 name_len,
+ const struct inode *dir)
+{
+ int rec_len = (name_len + 8 + EXT4_DIR_ROUND);
+
+ if (dir && ext4_hash_in_dirent(dir))
+ rec_len += sizeof(struct ext4_dir_entry_hash);
+ return (rec_len & ~EXT4_DIR_ROUND);
+}
+
/*
* If we ever get support for fs block sizes > page_size, we'll need
* to remove the #if statements in the next two functions...
#define DX_HASH_LEGACY_UNSIGNED 3
#define DX_HASH_HALF_MD4_UNSIGNED 4
#define DX_HASH_TEA_UNSIGNED 5
+#define DX_HASH_SIPHASH 6
static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc,
const void *address, unsigned int length)
};
#define fname_name(p) ((p)->disk_name.name)
+#define fname_usr_name(p) ((p)->usr_fname->name)
#define fname_len(p) ((p)->disk_name.len)
/*
struct ext4_dir_entry_2 *,
struct buffer_head *, char *, int,
unsigned int);
-#define ext4_check_dir_entry(dir, filp, de, bh, buf, size, offset) \
+#define ext4_check_dir_entry(dir, filp, de, bh, buf, size, offset) \
unlikely(__ext4_check_dir_entry(__func__, __LINE__, (dir), (filp), \
- (de), (bh), (buf), (size), (offset)))
+ (de), (bh), (buf), (size), (offset)))
extern int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
__u32 minor_hash,
struct ext4_dir_entry_2 *dirent,
void *buf, int buf_size,
struct ext4_filename *fname,
struct ext4_dir_entry_2 **dest_de);
-void ext4_insert_dentry(struct inode *inode,
+void ext4_insert_dentry(struct inode *dir, struct inode *inode,
struct ext4_dir_entry_2 *de,
int buf_size,
struct ext4_filename *fname);
unsigned int blocksize);
extern int ext4_handle_dirty_dirblock(handle_t *handle, struct inode *inode,
struct buffer_head *bh);
-extern int ext4_ci_compare(const struct inode *parent,
- const struct qstr *fname,
- const struct qstr *entry, bool quick);
extern int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name,
struct inode *inode);
extern int __ext4_link(struct inode *dir, struct inode *inode,
unsigned blocksize, struct dx_hash_info *hinfo,
struct dx_map_entry map[]);
static void dx_sort_map(struct dx_map_entry *map, unsigned count);
-static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
- struct dx_map_entry *offsets, int count, unsigned blocksize);
-static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
+static struct ext4_dir_entry_2 *dx_move_dirents(struct inode *dir, char *from,
+ char *to, struct dx_map_entry *offsets,
+ int count, unsigned int blocksize);
+static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
+ unsigned int blocksize);
static void dx_insert_block(struct dx_frame *frame,
u32 hash, ext4_lblk_t block);
static int ext4_htree_next_block(struct inode *dir, __u32 hash,
static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
{
- unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
- EXT4_DIR_REC_LEN(2) - infosize;
+ unsigned int entry_space = dir->i_sb->s_blocksize -
+ ext4_dir_rec_len(1, NULL) -
+ ext4_dir_rec_len(2, NULL) - infosize;
if (ext4_has_metadata_csum(dir->i_sb))
entry_space -= sizeof(struct dx_tail);
static inline unsigned dx_node_limit(struct inode *dir)
{
- unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
+ unsigned int entry_space = dir->i_sb->s_blocksize -
+ ext4_dir_rec_len(0, dir);
if (ext4_has_metadata_csum(dir->i_sb))
entry_space -= sizeof(struct dx_tail);
name = fname_crypto_str.name;
len = fname_crypto_str.len;
}
- ext4fs_dirhash(dir, de->name,
+ if (IS_CASEFOLDED(dir))
+ h.hash = EXT4_DIRENT_HASH(de);
+ else
+ ext4fs_dirhash(dir, de->name,
de->name_len, &h);
printk("%*.s:(E)%x.%u ", len, name,
h.hash, (unsigned) ((char *) de
(unsigned) ((char *) de - base));
#endif
}
- space += EXT4_DIR_REC_LEN(de->name_len);
+ space += ext4_dir_rec_len(de->name_len, dir);
names++;
}
de = ext4_next_entry(de, size);
root = (struct dx_root *) frame->bh->b_data;
if (root->info.hash_version != DX_HASH_TEA &&
root->info.hash_version != DX_HASH_HALF_MD4 &&
- root->info.hash_version != DX_HASH_LEGACY) {
+ root->info.hash_version != DX_HASH_LEGACY &&
+ root->info.hash_version != DX_HASH_SIPHASH) {
ext4_warning_inode(dir, "Unrecognised inode hash code %u",
root->info.hash_version);
goto fail;
}
+ if (ext4_hash_in_dirent(dir)) {
+ if (root->info.hash_version != DX_HASH_SIPHASH) {
+ ext4_warning_inode(dir,
+ "Hash in dirent, but hash is not SIPHASH");
+ goto fail;
+ }
+ } else {
+ if (root->info.hash_version == DX_HASH_SIPHASH) {
+ ext4_warning_inode(dir,
+ "Hash code is SIPHASH, but hash not in dirent");
+ goto fail;
+ }
+ }
if (fname)
hinfo = &fname->hinfo;
hinfo->hash_version = root->info.hash_version;
struct ext4_dir_entry_2 *de, *top;
int err = 0, count = 0;
struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
+ int csum = ext4_has_metadata_csum(dir->i_sb);
dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
(unsigned long)block));
return PTR_ERR(bh);
de = (struct ext4_dir_entry_2 *) bh->b_data;
+ /* csum entries are not larger in the casefolded encrypted case */
top = (struct ext4_dir_entry_2 *) ((char *) de +
dir->i_sb->s_blocksize -
- EXT4_DIR_REC_LEN(0));
+ ext4_dir_rec_len(0,
+ csum ? NULL : dir));
/* Check if the directory is encrypted */
if (IS_ENCRYPTED(dir)) {
err = fscrypt_prepare_readdir(dir);
/* silently ignore the rest of the block */
break;
}
- ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
+ if (ext4_hash_in_dirent(dir)) {
+ if (de->name_len && de->inode) {
+ hinfo->hash = EXT4_DIRENT_HASH(de);
+ hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
+ } else {
+ hinfo->hash = 0;
+ hinfo->minor_hash = 0;
+ }
+ } else {
+ ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
+ }
if ((hinfo->hash < start_hash) ||
((hinfo->hash == start_hash) &&
(hinfo->minor_hash < start_minor_hash)))
start_hash, start_minor_hash));
dir = file_inode(dir_file);
if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
- hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
+ if (ext4_hash_in_dirent(dir))
+ hinfo.hash_version = DX_HASH_SIPHASH;
+ else
+ hinfo.hash_version =
+ EXT4_SB(dir->i_sb)->s_def_hash_version;
if (hinfo.hash_version <= DX_HASH_TEA)
hinfo.hash_version +=
EXT4_SB(dir->i_sb)->s_hash_unsigned;
while ((char *) de < base + blocksize) {
if (de->name_len && de->inode) {
- ext4fs_dirhash(dir, de->name, de->name_len, &h);
+ if (ext4_hash_in_dirent(dir))
+ h.hash = EXT4_DIRENT_HASH(de);
+ else
+ ext4fs_dirhash(dir, de->name, de->name_len, &h);
map_tail--;
map_tail->hash = h.hash;
map_tail->offs = ((char *) de - base)>>2;
* Returns: 0 if the directory entry matches, more than 0 if it
* doesn't match or less than zero on error.
*/
-int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
- const struct qstr *entry, bool quick)
+static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
+ u8 *de_name, size_t de_name_len, bool quick)
{
const struct super_block *sb = parent->i_sb;
const struct unicode_map *um = sb->s_encoding;
+ struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
+ struct qstr entry = QSTR_INIT(de_name, de_name_len);
int ret;
+ if (IS_ENCRYPTED(parent)) {
+ const struct fscrypt_str encrypted_name =
+ FSTR_INIT(de_name, de_name_len);
+
+ decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
+ if (!decrypted_name.name)
+ return -ENOMEM;
+ ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
+ &decrypted_name);
+ if (ret < 0)
+ goto out;
+ entry.name = decrypted_name.name;
+ entry.len = decrypted_name.len;
+ }
+
if (quick)
- ret = utf8_strncasecmp_folded(um, name, entry);
+ ret = utf8_strncasecmp_folded(um, name, &entry);
else
- ret = utf8_strncasecmp(um, name, entry);
-
+ ret = utf8_strncasecmp(um, name, &entry);
if (ret < 0) {
/* Handle invalid character sequence as either an error
* or as an opaque byte sequence.
*/
if (sb_has_strict_encoding(sb))
- return -EINVAL;
-
- if (name->len != entry->len)
- return 1;
-
- return !!memcmp(name->name, entry->name, name->len);
+ ret = -EINVAL;
+ else if (name->len != entry.len)
+ ret = 1;
+ else
+ ret = !!memcmp(name->name, entry.name, entry.len);
}
-
+out:
+ kfree(decrypted_name.name);
return ret;
}
*
* Return: %true if the directory entry matches, otherwise %false.
*/
-static inline bool ext4_match(const struct inode *parent,
+static bool ext4_match(struct inode *parent,
const struct ext4_filename *fname,
- const struct ext4_dir_entry_2 *de)
+ struct ext4_dir_entry_2 *de)
{
struct fscrypt_name f;
-#ifdef CONFIG_UNICODE
- const struct qstr entry = {.name = de->name, .len = de->name_len};
-#endif
if (!de->inode)
return false;
if (fname->cf_name.name) {
struct qstr cf = {.name = fname->cf_name.name,
.len = fname->cf_name.len};
- return !ext4_ci_compare(parent, &cf, &entry, true);
+ if (IS_ENCRYPTED(parent)) {
+ struct dx_hash_info hinfo;
+
+ hinfo.hash_version = DX_HASH_SIPHASH;
+ hinfo.seed = NULL;
+ ext4fs_dirhash(parent, fname->cf_name.name,
+ fname_len(fname), &hinfo);
+ if (hinfo.hash != EXT4_DIRENT_HASH(de) ||
+ hinfo.minor_hash !=
+ EXT4_DIRENT_MINOR_HASH(de))
+ return 0;
+ }
+ return !ext4_ci_compare(parent, &cf, de->name,
+ de->name_len, true);
}
- return !ext4_ci_compare(parent, fname->usr_fname, &entry,
- false);
+ return !ext4_ci_compare(parent, fname->usr_fname, de->name,
+ de->name_len, false);
}
#endif
* Returns pointer to last entry moved.
*/
static struct ext4_dir_entry_2 *
-dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
+dx_move_dirents(struct inode *dir, char *from, char *to,
+ struct dx_map_entry *map, int count,
unsigned blocksize)
{
unsigned rec_len = 0;
while (count--) {
struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
(from + (map->offs<<2));
- rec_len = EXT4_DIR_REC_LEN(de->name_len);
+ rec_len = ext4_dir_rec_len(de->name_len, dir);
+
memcpy (to, de, rec_len);
((struct ext4_dir_entry_2 *) to)->rec_len =
ext4_rec_len_to_disk(rec_len, blocksize);
* Compact each dir entry in the range to the minimal rec_len.
* Returns pointer to last entry in range.
*/
-static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
+static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
+ unsigned int blocksize)
{
struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
unsigned rec_len = 0;
while ((char*)de < base + blocksize) {
next = ext4_next_entry(de, blocksize);
if (de->inode && de->name_len) {
- rec_len = EXT4_DIR_REC_LEN(de->name_len);
+ rec_len = ext4_dir_rec_len(de->name_len, dir);
if (de > to)
memmove(to, de, rec_len);
to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
hash2, split, count-split));
/* Fancy dance to stay within two buffers */
- de2 = dx_move_dirents(data1, data2, map + split, count - split,
+ de2 = dx_move_dirents(dir, data1, data2, map + split, count - split,
blocksize);
- de = dx_pack_dirents(data1, blocksize);
+ de = dx_pack_dirents(dir, data1, blocksize);
de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
(char *) de,
blocksize);
struct ext4_dir_entry_2 **dest_de)
{
struct ext4_dir_entry_2 *de;
- unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
+ unsigned short reclen = ext4_dir_rec_len(fname_len(fname), dir);
int nlen, rlen;
unsigned int offset = 0;
char *top;
return -EFSCORRUPTED;
if (ext4_match(dir, fname, de))
return -EEXIST;
- nlen = EXT4_DIR_REC_LEN(de->name_len);
+ nlen = ext4_dir_rec_len(de->name_len, dir);
rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
if ((de->inode ? rlen - nlen : rlen) >= reclen)
break;
return 0;
}
-void ext4_insert_dentry(struct inode *inode,
+void ext4_insert_dentry(struct inode *dir,
+ struct inode *inode,
struct ext4_dir_entry_2 *de,
int buf_size,
struct ext4_filename *fname)
int nlen, rlen;
- nlen = EXT4_DIR_REC_LEN(de->name_len);
+ nlen = ext4_dir_rec_len(de->name_len, dir);
rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
if (de->inode) {
struct ext4_dir_entry_2 *de1 =
ext4_set_de_type(inode->i_sb, de, inode->i_mode);
de->name_len = fname_len(fname);
memcpy(de->name, fname_name(fname), fname_len(fname));
+ if (ext4_hash_in_dirent(dir)) {
+ struct dx_hash_info hinfo;
+
+ hinfo.hash_version = DX_HASH_SIPHASH;
+ hinfo.seed = NULL;
+ ext4fs_dirhash(dir, fname_usr_name(fname),
+ fname_len(fname), &hinfo);
+ EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo.hash);
+ EXT4_DIRENT_HASHES(de)->minor_hash =
+ cpu_to_le32(hinfo.minor_hash);
+ }
}
/*
}
/* By now the buffer is marked for journaling */
- ext4_insert_dentry(inode, de, blocksize, fname);
+ ext4_insert_dentry(dir, inode, de, blocksize, fname);
/*
* XXX shouldn't update any times until successful
/* 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),
- blocksize);
+ de->rec_len = ext4_rec_len_to_disk(
+ blocksize - ext4_dir_rec_len(2, NULL), blocksize);
memset (&root->info, 0, sizeof(root->info));
root->info.info_length = sizeof(root->info);
- root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
+ if (ext4_hash_in_dirent(dir))
+ root->info.hash_version = DX_HASH_SIPHASH;
+ else
+ root->info.hash_version =
+ EXT4_SB(dir->i_sb)->s_def_hash_version;
+
entries = root->entries;
dx_set_block(entries, 1);
dx_set_count(entries, 1);
if (fname->hinfo.hash_version <= DX_HASH_TEA)
fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
- ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), &fname->hinfo);
+ if (ext4_hash_in_dirent(dir))
+ ext4fs_dirhash(dir, fname_usr_name(fname),
+ fname_len(fname), &fname->hinfo);
+ else
+ ext4fs_dirhash(dir, fname_name(fname),
+ fname_len(fname), &fname->hinfo);
memset(frames, 0, sizeof(frames));
frame = frames;
{
de->inode = cpu_to_le32(inode->i_ino);
de->name_len = 1;
- de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
+ de->rec_len = ext4_rec_len_to_disk(ext4_dir_rec_len(de->name_len, NULL),
blocksize);
strcpy(de->name, ".");
ext4_set_de_type(inode->i_sb, de, S_IFDIR);
de->name_len = 2;
if (!dotdot_real_len)
de->rec_len = ext4_rec_len_to_disk(blocksize -
- (csum_size + EXT4_DIR_REC_LEN(1)),
+ (csum_size + ext4_dir_rec_len(1, NULL)),
blocksize);
else
de->rec_len = ext4_rec_len_to_disk(
- EXT4_DIR_REC_LEN(de->name_len), blocksize);
+ ext4_dir_rec_len(de->name_len, NULL),
+ blocksize);
strcpy(de->name, "..");
ext4_set_de_type(inode->i_sb, de, S_IFDIR);
}
sb = inode->i_sb;
- if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
+ if (inode->i_size < ext4_dir_rec_len(1, NULL) +
+ ext4_dir_rec_len(2, NULL)) {
EXT4_ERROR_INODE(inode, "invalid size");
return true;
}
projects / linux.git / commitdiff