Merge tag 'upstream-4.10-rc1' of git://git.infradead.org/linux-ubifs

Pull ubifs updates from Richard Weinberger:

 - file encryption for UBIFS using the fscrypt framework

 - a fix to honor the dirty_writeback_interval sysctl

 - removal of dead code

* tag 'upstream-4.10-rc1' of git://git.infradead.org/linux-ubifs: (30 commits)
  ubifs: Initialize fstr_real_len
  ubifs: Use fscrypt ioctl() helpers
  ubifs: Use FS_CFLG_OWN_PAGES
  ubifs: Raise write version to 5
  ubifs: Implement UBIFS_FLG_ENCRYPTION
  ubifs: Implement UBIFS_FLG_DOUBLE_HASH
  ubifs: Use a random number for cookies
  ubifs: Add full hash lookup support
  ubifs: Rename tnc_read_node_nm
  ubifs: Add support for encrypted symlinks
  ubifs: Implement encrypted filenames
  ubifs: Make r5 hash binary string aware
  ubifs: Relax checks in ubifs_validate_entry()
  ubifs: Implement encrypt/decrypt for all IO
  ubifs: Constify struct inode pointer in ubifs_crypt_is_encrypted()
  ubifs: Introduce new data node field, compr_size
  ubifs: Enforce crypto policy in mmap
  ubifs: Massage assert in ubifs_xattr_set() wrt. fscrypto
  ubifs: Preload crypto context in ->lookup()
  ubifs: Enforce crypto policy in ->link and ->rename
  ...

fs/ubifs/Kconfig

@@ -50,3 +50,14 @@ config UBIFS_ATIME_SUPPORT
 	  strictatime is the "heavy", relatime is "lighter", etc.
 
 	  If unsure, say 'N'
+
+config UBIFS_FS_ENCRYPTION
+	bool "UBIFS Encryption"
+	depends on UBIFS_FS
+	select FS_ENCRYPTION
+	default n
+	help
+	  Enable encryption of UBIFS files and directories. This
+	  feature is similar to ecryptfs, but it is more memory
+	  efficient since it avoids caching the encrypted and
+	  decrypted pages in the page cache.

fs/ubifs/Makefile

@@ -5,3 +5,4 @@ ubifs-y += tnc.o master.o scan.o replay.o log.o commit.o gc.o orphan.o
 ubifs-y += budget.o find.o tnc_commit.o compress.o lpt.o lprops.o
 ubifs-y += recovery.o ioctl.o lpt_commit.o tnc_misc.o xattr.o debug.o
 ubifs-y += misc.o
+ubifs-$(CONFIG_UBIFS_FS_ENCRYPTION) += crypto.o

fs/ubifs/crypto.c

+#include "ubifs.h"
+
+static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len)
+{
+	return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
+			       ctx, len);
+}
+
+static int ubifs_crypt_set_context(struct inode *inode, const void *ctx,
+				   size_t len, void *fs_data)
+{
+	return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
+			       ctx, len, 0);
+}
+
+static bool ubifs_crypt_empty_dir(struct inode *inode)
+{
+	return ubifs_check_dir_empty(inode) == 0;
+}
+
+static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
+{
+	if (S_ISLNK(inode->i_mode))
+		return UBIFS_MAX_INO_DATA;
+	else
+		return UBIFS_MAX_NLEN;
+}
+
+static int ubifs_key_prefix(struct inode *inode, u8 **key)
+{
+	static char prefix[] = "ubifs:";
+
+	*key = prefix;
+
+	return sizeof(prefix) - 1;
+}
+
+int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
+		  unsigned int in_len, unsigned int *out_len, int block)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	void *p = &dn->data;
+	struct page *ret;
+	unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE);
+
+	ubifs_assert(pad_len <= *out_len);
+	dn->compr_size = cpu_to_le16(in_len);
+
+	/* pad to full block cipher length */
+	if (pad_len != in_len)
+		memset(p + in_len, 0, pad_len - in_len);
+
+	ret = fscrypt_encrypt_page(inode, virt_to_page(&dn->data), pad_len,
+			offset_in_page(&dn->data), block, GFP_NOFS);
+	if (IS_ERR(ret)) {
+		ubifs_err(c, "fscrypt_encrypt_page failed: %ld", PTR_ERR(ret));
+		return PTR_ERR(ret);
+	}
+	*out_len = pad_len;
+
+	return 0;
+}
+
+int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
+		  unsigned int *out_len, int block)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	int err;
+	unsigned int clen = le16_to_cpu(dn->compr_size);
+	unsigned int dlen = *out_len;
+
+	if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
+		ubifs_err(c, "bad compr_size: %i", clen);
+		return -EINVAL;
+	}
+
+	ubifs_assert(dlen <= UBIFS_BLOCK_SIZE);
+	err = fscrypt_decrypt_page(inode, virt_to_page(&dn->data), dlen,
+			offset_in_page(&dn->data), block);
+	if (err) {
+		ubifs_err(c, "fscrypt_decrypt_page failed: %i", err);
+		return err;
+	}
+	*out_len = clen;
+
+	return 0;
+}
+
+struct fscrypt_operations ubifs_crypt_operations = {
+	.flags			= FS_CFLG_OWN_PAGES,
+	.get_context		= ubifs_crypt_get_context,
+	.set_context		= ubifs_crypt_set_context,
+	.is_encrypted		= __ubifs_crypt_is_encrypted,
+	.empty_dir		= ubifs_crypt_empty_dir,
+	.max_namelen		= ubifs_crypt_max_namelen,
+	.key_prefix		= ubifs_key_prefix,
+};

fs/ubifs/debug.c

@@ -233,7 +233,7 @@ static void dump_ch(const struct ubifs_ch *ch)
 void ubifs_dump_inode(struct ubifs_info *c, const struct inode *inode)
 {
 	const struct ubifs_inode *ui = ubifs_inode(inode);
-	struct qstr nm = { .name = NULL };
+	struct fscrypt_name nm = {0};
 	union ubifs_key key;
 	struct ubifs_dent_node *dent, *pdent = NULL;
 	int count = 2;
@@ -289,8 +289,8 @@ void ubifs_dump_inode(struct ubifs_info *c, const struct inode *inode)
 		pr_err("\t%d: %s (%s)\n",
 		       count++, dent->name, get_dent_type(dent->type));
 
-		nm.name = dent->name;
-		nm.len = le16_to_cpu(dent->nlen);
+		fname_name(&nm) = dent->name;
+		fname_len(&nm) = le16_to_cpu(dent->nlen);
 		kfree(pdent);
 		pdent = dent;
 		key_read(c, &dent->key, &key);
@@ -1107,7 +1107,7 @@ int dbg_check_dir(struct ubifs_info *c, const struct inode *dir)
 	unsigned int nlink = 2;
 	union ubifs_key key;
 	struct ubifs_dent_node *dent, *pdent = NULL;
-	struct qstr nm = { .name = NULL };
+	struct fscrypt_name nm = {0};
 	loff_t size = UBIFS_INO_NODE_SZ;
 
 	if (!dbg_is_chk_gen(c))
@@ -1128,9 +1128,9 @@ int dbg_check_dir(struct ubifs_info *c, const struct inode *dir)
 			return err;
 		}
 
-		nm.name = dent->name;
-		nm.len = le16_to_cpu(dent->nlen);
-		size += CALC_DENT_SIZE(nm.len);
+		fname_name(&nm) = dent->name;
+		fname_len(&nm) = le16_to_cpu(dent->nlen);
+		size += CALC_DENT_SIZE(fname_len(&nm));
 		if (dent->type == UBIFS_ITYPE_DIR)
 			nlink += 1;
 		kfree(pdent);

fs/ubifs/file.c

@@ -78,6 +78,13 @@ static int read_block(struct inode *inode, void *addr, unsigned int block,
 		goto dump;
 
 	dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
+
+	if (ubifs_crypt_is_encrypted(inode)) {
+		err = ubifs_decrypt(inode, dn, &dlen, block);
+		if (err)
+			goto dump;
+	}
+
 	out_len = UBIFS_BLOCK_SIZE;
 	err = ubifs_decompress(c, &dn->data, dlen, addr, &out_len,
 			       le16_to_cpu(dn->compr_type));
@@ -650,6 +657,13 @@ static int populate_page(struct ubifs_info *c, struct page *page,
 
 			dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
 			out_len = UBIFS_BLOCK_SIZE;
+
+			if (ubifs_crypt_is_encrypted(inode)) {
+				err = ubifs_decrypt(inode, dn, &dlen, page_block);
+				if (err)
+					goto out_err;
+			}
+
 			err = ubifs_decompress(c, &dn->data, dlen, addr, &out_len,
 					       le16_to_cpu(dn->compr_type));
 			if (err || len != out_len)
@@ -1594,6 +1608,15 @@ static const struct vm_operations_struct ubifs_file_vm_ops = {
 static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	int err;
+	struct inode *inode = file->f_mapping->host;
+
+	if (ubifs_crypt_is_encrypted(inode)) {
+		err = fscrypt_get_encryption_info(inode);
+		if (err)
+			return -EACCES;
+		if (!fscrypt_has_encryption_key(inode))
+			return -ENOKEY;
+	}
 
 	err = generic_file_mmap(file, vma);
 	if (err)
@@ -1605,6 +1628,88 @@ static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
+static int ubifs_file_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+	struct dentry *dir;
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+
+	if (ubifs_crypt_is_encrypted(inode)) {
+		ret = fscrypt_get_encryption_info(inode);
+		if (ret)
+			return -EACCES;
+		if (!fscrypt_has_encryption_key(inode))
+			return -ENOKEY;
+	}
+
+	dir = dget_parent(file_dentry(filp));
+	if (ubifs_crypt_is_encrypted(d_inode(dir)) &&
+			!fscrypt_has_permitted_context(d_inode(dir), inode)) {
+		ubifs_err(c, "Inconsistent encryption contexts: %lu/%lu",
+			  (unsigned long) d_inode(dir)->i_ino,
+			  (unsigned long) inode->i_ino);
+		dput(dir);
+		ubifs_ro_mode(c, -EPERM);
+		return -EPERM;
+	}
+	dput(dir);
+
+	return 0;
+}
+
+static const char *ubifs_get_link(struct dentry *dentry,
+					    struct inode *inode,
+					    struct delayed_call *done)
+{
+	int err;
+	struct fscrypt_symlink_data *sd;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	struct fscrypt_str cstr;
+	struct fscrypt_str pstr;
+
+	if (!ubifs_crypt_is_encrypted(inode))
+		return ui->data;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	err = fscrypt_get_encryption_info(inode);
+	if (err)
+		return ERR_PTR(err);
+
+	sd = (struct fscrypt_symlink_data *)ui->data;
+	cstr.name = sd->encrypted_path;
+	cstr.len = le16_to_cpu(sd->len);
+
+	if (cstr.len == 0)
+		return ERR_PTR(-ENOENT);
+
+	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > ui->data_len)
+		return ERR_PTR(-EIO);
+
+	err = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);
+	if (err)
+		return ERR_PTR(err);
+
+	err = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);
+	if (err) {
+		fscrypt_fname_free_buffer(&pstr);
+		return ERR_PTR(err);
+	}
+
+	pstr.name[pstr.len] = '\0';
+
+	// XXX this probably won't happen anymore...
+	if (pstr.name[0] == '\0') {
+		fscrypt_fname_free_buffer(&pstr);
+		return ERR_PTR(-ENOENT);
+	}
+
+	set_delayed_call(done, kfree_link, pstr.name);
+	return pstr.name;
+}
+
+
 const struct address_space_operations ubifs_file_address_operations = {
 	.readpage       = ubifs_readpage,
 	.writepage      = ubifs_writepage,
@@ -1629,7 +1734,7 @@ const struct inode_operations ubifs_file_inode_operations = {
 
 const struct inode_operations ubifs_symlink_inode_operations = {
 	.readlink    = generic_readlink,
-	.get_link    = simple_get_link,
+	.get_link    = ubifs_get_link,
 	.setattr     = ubifs_setattr,
 	.getattr     = ubifs_getattr,
 	.listxattr   = ubifs_listxattr,
@@ -1647,6 +1752,7 @@ const struct file_operations ubifs_file_operations = {
 	.unlocked_ioctl = ubifs_ioctl,
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
+	.open		= ubifs_file_open,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl   = ubifs_compat_ioctl,
 #endif

fs/ubifs/gc.c

@@ -846,10 +846,6 @@ int ubifs_gc_start_commit(struct ubifs_info *c)
 	 */
 	while (1) {
 		lp = ubifs_fast_find_freeable(c);
-		if (IS_ERR(lp)) {
-			err = PTR_ERR(lp);
-			goto out;
-		}
 		if (!lp)
 			break;
 		ubifs_assert(!(lp->flags & LPROPS_TAKEN));

fs/ubifs/io.c

@@ -452,16 +452,22 @@ static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
  */
 static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
 {
+	ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);
+	unsigned long long delta = dirty_writeback_interval;
+
+	/* centi to milli, milli to nano, then 10% */
+	delta *= 10ULL * NSEC_PER_MSEC / 10ULL;
+
 	ubifs_assert(!hrtimer_active(&wbuf->timer));
+	ubifs_assert(delta <= ULONG_MAX);
 
 	if (wbuf->no_timer)
 		return;
 	dbg_io("set timer for jhead %s, %llu-%llu millisecs",
 	       dbg_jhead(wbuf->jhead),
-	       div_u64(ktime_to_ns(wbuf->softlimit), USEC_PER_SEC),
-	       div_u64(ktime_to_ns(wbuf->softlimit) + wbuf->delta,
-		       USEC_PER_SEC));
-	hrtimer_start_range_ns(&wbuf->timer, wbuf->softlimit, wbuf->delta,
+	       div_u64(ktime_to_ns(softlimit), USEC_PER_SEC),
+	       div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC));
+	hrtimer_start_range_ns(&wbuf->timer, softlimit, delta,
 			       HRTIMER_MODE_REL);
 }
 
@@ -1059,10 +1065,6 @@ int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
 
 	hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	wbuf->timer.function = wbuf_timer_callback_nolock;
-	wbuf->softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0);
-	wbuf->delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT;
-	wbuf->delta *= 1000000000ULL;
-	ubifs_assert(wbuf->delta <= ULONG_MAX);
 	return 0;
 }
 

fs/ubifs/ioctl.c

@@ -181,6 +181,26 @@ long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		mnt_drop_write_file(file);
 		return err;
 	}
+	case FS_IOC_SET_ENCRYPTION_POLICY: {
+#ifdef CONFIG_UBIFS_FS_ENCRYPTION
+		struct ubifs_info *c = inode->i_sb->s_fs_info;
+
+		err = ubifs_enable_encryption(c);
+		if (err)
+			return err;
+
+		return fscrypt_ioctl_set_policy(file, (const void __user *)arg);
+#else
+		return -EOPNOTSUPP;
+#endif
+	}
+	case FS_IOC_GET_ENCRYPTION_POLICY: {
+#ifdef CONFIG_UBIFS_FS_ENCRYPTION
+		return fscrypt_ioctl_get_policy(file, (void __user *)arg);
+#else
+		return -EOPNOTSUPP;
+#endif
+	}
 
 	default:
 		return -ENOTTY;

fs/ubifs/key.h

@@ -69,7 +69,7 @@ static inline uint32_t key_r5_hash(const char *s, int len)
 	uint32_t a = 0;
 	const signed char *str = (const signed char *)s;
 
-	while (*str) {
+	while (len--) {
 		a += *str << 4;
 		a += *str >> 4;
 		a *= 11;
@@ -153,13 +153,13 @@ static inline void highest_ino_key(const struct ubifs_info *c,
  * @c: UBIFS file-system description object
  * @key: key to initialize
  * @inum: parent inode number
- * @nm: direntry name and length
+ * @nm: direntry name and length. Not a string when encrypted!
  */
 static inline void dent_key_init(const struct ubifs_info *c,
 				 union ubifs_key *key, ino_t inum,
-				 const struct qstr *nm)
+				 const struct fscrypt_name *nm)
 {
-	uint32_t hash = c->key_hash(nm->name, nm->len);
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
 
 	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
 	key->u32[0] = inum;
@@ -191,10 +191,11 @@ static inline void dent_key_init_hash(const struct ubifs_info *c,
  * @nm: direntry name and length
  */
 static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
-				       ino_t inum, const struct qstr *nm)
+				       ino_t inum,
+				       const struct fscrypt_name *nm)
 {
 	union ubifs_key *key = k;
-	uint32_t hash = c->key_hash(nm->name, nm->len);
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
 
 	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
 	key->j32[0] = cpu_to_le32(inum);
@@ -225,9 +226,9 @@ static inline void lowest_dent_key(const struct ubifs_info *c,
  */
 static inline void xent_key_init(const struct ubifs_info *c,
 				 union ubifs_key *key, ino_t inum,
-				 const struct qstr *nm)
+				 const struct fscrypt_name *nm)
 {
-	uint32_t hash = c->key_hash(nm->name, nm->len);
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
 
 	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
 	key->u32[0] = inum;
@@ -242,10 +243,10 @@ static inline void xent_key_init(const struct ubifs_info *c,
  * @nm: extended attribute entry name and length
  */
 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
-				       ino_t inum, const struct qstr *nm)
+				       ino_t inum, const struct fscrypt_name *nm)
 {
 	union ubifs_key *key = k;
-	uint32_t hash = c->key_hash(nm->name, nm->len);
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
 
 	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
 	key->j32[0] = cpu_to_le32(inum);

fs/ubifs/replay.c

@@ -61,7 +61,7 @@ struct replay_entry {
 	struct list_head list;
 	union ubifs_key key;
 	union {
-		struct qstr nm;
+		struct fscrypt_name nm;
 		struct {
 			loff_t old_size;
 			loff_t new_size;
@@ -327,7 +327,7 @@ static void destroy_replay_list(struct ubifs_info *c)
 
 	list_for_each_entry_safe(r, tmp, &c->replay_list, list) {
 		if (is_hash_key(c, &r->key))
-			kfree(r->nm.name);
+			kfree(fname_name(&r->nm));
 		list_del(&r->list);
 		kfree(r);
 	}
@@ -430,10 +430,10 @@ static int insert_dent(struct ubifs_info *c, int lnum, int offs, int len,
 	r->deletion = !!deletion;
 	r->sqnum = sqnum;
 	key_copy(c, key, &r->key);
-	r->nm.len = nlen;
+	fname_len(&r->nm) = nlen;
 	memcpy(nbuf, name, nlen);
 	nbuf[nlen] = '\0';
-	r->nm.name = nbuf;
+	fname_name(&r->nm) = nbuf;
 
 	list_add_tail(&r->list, &c->replay_list);
 	return 0;
@@ -456,7 +456,7 @@ int ubifs_validate_entry(struct ubifs_info *c,
 	if (le32_to_cpu(dent->ch.len) != nlen + UBIFS_DENT_NODE_SZ + 1 ||
 	    dent->type >= UBIFS_ITYPES_CNT ||
 	    nlen > UBIFS_MAX_NLEN || dent->name[nlen] != 0 ||
-	    strnlen(dent->name, nlen) != nlen ||
+	    (key_type == UBIFS_XENT_KEY && strnlen(dent->name, nlen) != nlen) ||
 	    le64_to_cpu(dent->inum) > MAX_INUM) {
 		ubifs_err(c, "bad %s node", key_type == UBIFS_DENT_KEY ?
 			  "directory entry" : "extended attribute entry");

fs/ubifs/sb.c

@@ -163,6 +163,7 @@ static int create_default_filesystem(struct ubifs_info *c)
 	tmp64 = (long long)max_buds * c->leb_size;
 	if (big_lpt)
 		sup_flags |= UBIFS_FLG_BIGLPT;
+	sup_flags |= UBIFS_FLG_DOUBLE_HASH;
 
 	sup->ch.node_type  = UBIFS_SB_NODE;
 	sup->key_hash      = UBIFS_KEY_HASH_R5;
@@ -465,6 +466,16 @@ static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 		goto failed;
 	}
 
+	if (!c->double_hash && c->fmt_version >= 5) {
+		err = 16;
+		goto failed;
+	}
+
+	if (c->encrypted && c->fmt_version < 5) {
+		err = 17;
+		goto failed;
+	}
+
 	return 0;
 
 failed:
@@ -620,6 +631,24 @@ int ubifs_read_superblock(struct ubifs_info *c)
 	memcpy(&c->uuid, &sup->uuid, 16);
 	c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
 	c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
+	c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
+	c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
+
+	if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
+		ubifs_err(c, "Unknown feature flags found: %#x",
+			  sup_flags & ~UBIFS_FLG_MASK);
+		err = -EINVAL;
+		goto out;
+	}
+
+#ifndef CONFIG_UBIFS_FS_ENCRYPTION
+	if (c->encrypted) {
+		ubifs_err(c, "file system contains encrypted files but UBIFS"
+			     " was built without crypto support.");
+		err = -EINVAL;
+		goto out;
+	}
+#endif
 
 	/* Automatically increase file system size to the maximum size */
 	c->old_leb_cnt = c->leb_cnt;
@@ -807,3 +836,33 @@ int ubifs_fixup_free_space(struct ubifs_info *c)
 	ubifs_msg(c, "free space fixup complete");
 	return err;
 }
+
+int ubifs_enable_encryption(struct ubifs_info *c)
+{
+	int err;
+	struct ubifs_sb_node *sup;
+
+	if (c->encrypted)
+		return 0;
+
+	if (c->ro_mount || c->ro_media)
+		return -EROFS;
+
+	if (c->fmt_version < 5) {
+		ubifs_err(c, "on-flash format version 5 is needed for encryption");
+		return -EINVAL;
+	}
+
+	sup = ubifs_read_sb_node(c);
+	if (IS_ERR(sup))
+		return PTR_ERR(sup);
+
+	sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);
+
+	err = ubifs_write_sb_node(c, sup);
+	if (!err)
+		c->encrypted = 1;
+	kfree(sup);
+
+	return err;
+}

fs/ubifs/super.c

@@ -198,7 +198,6 @@ struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
 		}
 		memcpy(ui->data, ino->data, ui->data_len);
 		((char *)ui->data)[ui->data_len] = '\0';
-		inode->i_link = ui->data;
 		break;
 	case S_IFBLK:
 	case S_IFCHR:
@@ -380,6 +379,9 @@ static void ubifs_evict_inode(struct inode *inode)
 	}
 done:
 	clear_inode(inode);
+#ifdef CONFIG_UBIFS_FS_ENCRYPTION
+	fscrypt_put_encryption_info(inode, NULL);
+#endif
 }
 
 static void ubifs_dirty_inode(struct inode *inode, int flags)
@@ -1207,7 +1209,8 @@ static int mount_ubifs(struct ubifs_info *c)
 		bu_init(c);
 
 	if (!c->ro_mount) {
-		c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ,
+		c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
+					       UBIFS_CIPHER_BLOCK_SIZE,
 					       GFP_KERNEL);
 		if (!c->write_reserve_buf)
 			goto out_free;
@@ -1620,7 +1623,8 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 		goto out;
 	}
 
-	c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ, GFP_KERNEL);
+	c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
+				       UBIFS_CIPHER_BLOCK_SIZE, GFP_KERNEL);
 	if (!c->write_reserve_buf) {
 		err = -ENOMEM;
 		goto out;
@@ -1995,6 +1999,12 @@ static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
 	return c;
 }
 
+#ifndef CONFIG_UBIFS_FS_ENCRYPTION
+struct fscrypt_operations ubifs_crypt_operations = {
+	.is_encrypted		= __ubifs_crypt_is_encrypted,
+};
+#endif
+
 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct ubifs_info *c = sb->s_fs_info;
@@ -2041,6 +2051,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
 	sb->s_op = &ubifs_super_operations;
 	sb->s_xattr = ubifs_xattr_handlers;
+	sb->s_cop = &ubifs_crypt_operations;
 
 	mutex_lock(&c->umount_mutex);
 	err = mount_ubifs(c);

fs/ubifs/ubifs-media.h

@@ -46,7 +46,7 @@
  * UBIFS went into mainline kernel with format version 4. The older formats
  * were development formats.
  */
-#define UBIFS_FORMAT_VERSION 4
+#define UBIFS_FORMAT_VERSION 5
 
 /*
  * Read-only compatibility version. If the UBIFS format is changed, older UBIFS
@@ -300,6 +300,13 @@ enum {
 /* The largest UBIFS node */
 #define UBIFS_MAX_NODE_SZ UBIFS_MAX_INO_NODE_SZ
 
+/*
+ * xattr name of UBIFS encryption context, we don't use a prefix
+ * nor a long name to not waste space on the flash.
+ */
+#define UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT "c"
+
+
 /*
  * On-flash inode flags.
  *
@@ -309,6 +316,7 @@ enum {
  * UBIFS_APPEND_FL: writes to the inode may only append data
  * UBIFS_DIRSYNC_FL: I/O on this directory inode has to be synchronous
  * UBIFS_XATTR_FL: this inode is the inode for an extended attribute value
+ * UBIFS_CRYPT_FL: use encryption for this inode
  *
  * Note, these are on-flash flags which correspond to ioctl flags
  * (@FS_COMPR_FL, etc). They have the same values now, but generally, do not
@@ -321,6 +329,7 @@ enum {
 	UBIFS_APPEND_FL    = 0x08,
 	UBIFS_DIRSYNC_FL   = 0x10,
 	UBIFS_XATTR_FL     = 0x20,
+	UBIFS_CRYPT_FL     = 0x40,
 };
 
 /* Inode flag bits used by UBIFS */
@@ -409,12 +418,19 @@ enum {
  *
  * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
  * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed
+ * UBIFS_FLG_DOUBLE_HASH: store a 32bit cookie in directory entry nodes to
+ *			  support 64bit cookies for lookups by hash
+ * UBIFS_FLG_ENCRYPTION: this filesystem contains encrypted files
  */
 enum {
 	UBIFS_FLG_BIGLPT = 0x02,
 	UBIFS_FLG_SPACE_FIXUP = 0x04,
+	UBIFS_FLG_DOUBLE_HASH = 0x08,
+	UBIFS_FLG_ENCRYPTION = 0x10,
 };
 
+#define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT|UBIFS_FLG_SPACE_FIXUP|UBIFS_FLG_DOUBLE_HASH|UBIFS_FLG_ENCRYPTION)
+
 /**
  * struct ubifs_ch - common header node.
  * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)
@@ -521,7 +537,8 @@ struct ubifs_ino_node {
  * @padding1: reserved for future, zeroes
  * @type: type of the target inode (%UBIFS_ITYPE_REG, %UBIFS_ITYPE_DIR, etc)
  * @nlen: name length
- * @padding2: reserved for future, zeroes
+ * @cookie: A 32bits random number, used to construct a 64bits
+ *          identifier.
  * @name: zero-terminated name
  *
  * Note, do not forget to amend 'zero_dent_node_unused()' function when
@@ -534,7 +551,7 @@ struct ubifs_dent_node {
 	__u8 padding1;
 	__u8 type;
 	__le16 nlen;
-	__u8 padding2[4]; /* Watch 'zero_dent_node_unused()' if changing! */
+	__le32 cookie;
 	__u8 name[];
 } __packed;
 
@@ -544,18 +561,16 @@ struct ubifs_dent_node {
  * @key: node key
  * @size: uncompressed data size in bytes
  * @compr_type: compression type (%UBIFS_COMPR_NONE, %UBIFS_COMPR_LZO, etc)
- * @padding: reserved for future, zeroes
+ * @compr_size: compressed data size in bytes, only valid when data is encrypted
  * @data: data
  *
- * Note, do not forget to amend 'zero_data_node_unused()' function when
- * changing the padding fields.
  */
 struct ubifs_data_node {
 	struct ubifs_ch ch;
 	__u8 key[UBIFS_MAX_KEY_LEN];
 	__le32 size;
 	__le16 compr_type;
-	__u8 padding[2]; /* Watch 'zero_data_node_unused()' if changing! */
+	__le16 compr_size;
 	__u8 data[];
 } __packed;
 

fs/ubifs/xattr.c

@@ -97,7 +97,7 @@ static const struct file_operations empty_fops;
  * of failure.
  */
 static int create_xattr(struct ubifs_info *c, struct inode *host,
-			const struct qstr *nm, const void *value, int size)
+			const struct fscrypt_name *nm, const void *value, int size)
 {
 	int err, names_len;
 	struct inode *inode;
@@ -117,7 +117,7 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
 	 * extended attributes if the name list becomes larger. This limitation
 	 * is artificial for UBIFS, though.
 	 */
-	names_len = host_ui->xattr_names + host_ui->xattr_cnt + nm->len + 1;
+	names_len = host_ui->xattr_names + host_ui->xattr_cnt + fname_len(nm) + 1;
 	if (names_len > XATTR_LIST_MAX) {
 		ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
 			  host->i_ino, names_len, XATTR_LIST_MAX);
@@ -154,9 +154,18 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
 	mutex_lock(&host_ui->ui_mutex);
 	host->i_ctime = ubifs_current_time(host);
 	host_ui->xattr_cnt += 1;
-	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
+	host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
 	host_ui->xattr_size += CALC_XATTR_BYTES(size);
-	host_ui->xattr_names += nm->len;
+	host_ui->xattr_names += fname_len(nm);
+
+	/*
+	 * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we
+	 * have to set the UBIFS_CRYPT_FL flag on the host inode.
+	 * To avoid multiple updates of the same inode in the same operation,
+	 * let's do it here.
+	 */
+	if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
+		host_ui->flags |= UBIFS_CRYPT_FL;
 
 	err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
 	if (err)
@@ -170,9 +179,10 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
 
 out_cancel:
 	host_ui->xattr_cnt -= 1;
-	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
+	host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
 	host_ui->xattr_size -= CALC_XATTR_BYTES(size);
-	host_ui->xattr_names -= nm->len;
+	host_ui->xattr_names -= fname_len(nm);
+	host_ui->flags &= ~UBIFS_CRYPT_FL;
 	mutex_unlock(&host_ui->ui_mutex);
 out_free:
 	make_bad_inode(inode);
@@ -269,22 +279,28 @@ static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
 	return ERR_PTR(-EINVAL);
 }
 
-static int __ubifs_setxattr(struct inode *host, const char *name,
-			    const void *value, size_t size, int flags)
+int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
+		    size_t size, int flags)
 {
 	struct inode *inode;
 	struct ubifs_info *c = host->i_sb->s_fs_info;
-	struct qstr nm = QSTR_INIT(name, strlen(name));
+	struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 	struct ubifs_dent_node *xent;
 	union ubifs_key key;
 	int err;
 
+	/*
+	 * Creating an encryption context is done unlocked since we
+	 * operate on a new inode which is not visible to other users
+	 * at this point.
+	 */
+	if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) != 0)
 		ubifs_assert(inode_is_locked(host));
 
 	if (size > UBIFS_MAX_INO_DATA)
 		return -ERANGE;
 
-	if (nm.len > UBIFS_MAX_NLEN)
+	if (fname_len(&nm) > UBIFS_MAX_NLEN)
 		return -ENAMETOOLONG;
 
 	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
@@ -329,18 +345,18 @@ static int __ubifs_setxattr(struct inode *host, const char *name,
 	return err;
 }
 
-static ssize_t __ubifs_getxattr(struct inode *host, const char *name,
-				void *buf, size_t size)
+ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
+			size_t size)
 {
 	struct inode *inode;
 	struct ubifs_info *c = host->i_sb->s_fs_info;
-	struct qstr nm = QSTR_INIT(name, strlen(name));
+	struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 	struct ubifs_inode *ui;
 	struct ubifs_dent_node *xent;
 	union ubifs_key key;
 	int err;
 
-	if (nm.len > UBIFS_MAX_NLEN)
+	if (fname_len(&nm) > UBIFS_MAX_NLEN)
 		return -ENAMETOOLONG;
 
 	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
@@ -387,6 +403,20 @@ static ssize_t __ubifs_getxattr(struct inode *host, const char *name,
 	return err;
 }
 
+static bool xattr_visible(const char *name)
+{
+	/* File encryption related xattrs are for internal use only */
+	if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
+		return false;
+
+	/* Show trusted namespace only for "power" users */
+	if (strncmp(name, XATTR_TRUSTED_PREFIX,
+		    XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
+		return false;
+
+	return true;
+}
+
 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 {
 	union ubifs_key key;
@@ -395,7 +425,7 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 	struct ubifs_inode *host_ui = ubifs_inode(host);
 	struct ubifs_dent_node *xent, *pxent = NULL;
 	int err, len, written = 0;
-	struct qstr nm = { .name = NULL };
+	struct fscrypt_name nm = {0};
 
 	dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
 		dentry, size);
@@ -419,15 +449,12 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 			break;
 		}
 
-		nm.name = xent->name;
-		nm.len = le16_to_cpu(xent->nlen);
+		fname_name(&nm) = xent->name;
+		fname_len(&nm) = le16_to_cpu(xent->nlen);
 
-		/* Show trusted namespace only for "power" users */
-		if (strncmp(xent->name, XATTR_TRUSTED_PREFIX,
-			    XATTR_TRUSTED_PREFIX_LEN) ||
-		    capable(CAP_SYS_ADMIN)) {
-			memcpy(buffer + written, nm.name, nm.len + 1);
-			written += nm.len + 1;
+		if (xattr_visible(xent->name)) {
+			memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1);
+			written += fname_len(&nm) + 1;
 		}
 
 		kfree(pxent);
@@ -446,7 +473,7 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 }
 
 static int remove_xattr(struct ubifs_info *c, struct inode *host,
-			struct inode *inode, const struct qstr *nm)
+			struct inode *inode, const struct fscrypt_name *nm)
 {
 	int err;
 	struct ubifs_inode *host_ui = ubifs_inode(host);
@@ -463,9 +490,9 @@ static int remove_xattr(struct ubifs_info *c, struct inode *host,
 	mutex_lock(&host_ui->ui_mutex);
 	host->i_ctime = ubifs_current_time(host);
 	host_ui->xattr_cnt -= 1;
-	host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
+	host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
 	host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
-	host_ui->xattr_names -= nm->len;
+	host_ui->xattr_names -= fname_len(nm);
 
 	err = ubifs_jnl_delete_xattr(c, host, inode, nm);
 	if (err)
@@ -477,27 +504,27 @@ static int remove_xattr(struct ubifs_info *c, struct inode *host,
 
 out_cancel:
 	host_ui->xattr_cnt += 1;
-	host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
+	host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
 	host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
-	host_ui->xattr_names += nm->len;
+	host_ui->xattr_names += fname_len(nm);
 	mutex_unlock(&host_ui->ui_mutex);
 	ubifs_release_budget(c, &req);
 	make_bad_inode(inode);
 	return err;
 }
 
-static int __ubifs_removexattr(struct inode *host, const char *name)
+static int ubifs_xattr_remove(struct inode *host, const char *name)
 {
 	struct inode *inode;
 	struct ubifs_info *c = host->i_sb->s_fs_info;
-	struct qstr nm = QSTR_INIT(name, strlen(name));
+	struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 	struct ubifs_dent_node *xent;
 	union ubifs_key key;
 	int err;
 
 	ubifs_assert(inode_is_locked(host));
 
-	if (nm.len > UBIFS_MAX_NLEN)
+	if (fname_len(&nm) > UBIFS_MAX_NLEN)
 		return -ENAMETOOLONG;
 
 	xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
@@ -548,7 +575,8 @@ static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
 		}
 		strcpy(name, XATTR_SECURITY_PREFIX);
 		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
-		err = __ubifs_setxattr(inode, name, xattr->value, xattr->value_len, 0);
+		err = ubifs_xattr_set(inode, name, xattr->value,
+				      xattr->value_len, 0);
 		kfree(name);
 		if (err < 0)
 			break;
@@ -572,7 +600,7 @@ int ubifs_init_security(struct inode *dentry, struct inode *inode,
 	return err;
 }
 
-static int ubifs_xattr_get(const struct xattr_handler *handler,
+static int xattr_get(const struct xattr_handler *handler,
 			   struct dentry *dentry, struct inode *inode,
 			   const char *name, void *buffer, size_t size)
 {
@@ -580,10 +608,10 @@ static int ubifs_xattr_get(const struct xattr_handler *handler,
 		inode->i_ino, dentry, size);
 
 	name = xattr_full_name(handler, name);
-	return __ubifs_getxattr(inode, name, buffer, size);
+	return ubifs_xattr_get(inode, name, buffer, size);
 }
 
-static int ubifs_xattr_set(const struct xattr_handler *handler,
+static int xattr_set(const struct xattr_handler *handler,
 			   struct dentry *dentry, struct inode *inode,
 			   const char *name, const void *value,
 			   size_t size, int flags)
@@ -594,27 +622,27 @@ static int ubifs_xattr_set(const struct xattr_handler *handler,
 	name = xattr_full_name(handler, name);
 
 	if (value)
-		return __ubifs_setxattr(inode, name, value, size, flags);
+		return ubifs_xattr_set(inode, name, value, size, flags);
 	else
-		return __ubifs_removexattr(inode, name);
+		return ubifs_xattr_remove(inode, name);
 }
 
 static const struct xattr_handler ubifs_user_xattr_handler = {
 	.prefix = XATTR_USER_PREFIX,
-	.get = ubifs_xattr_get,
-	.set = ubifs_xattr_set,
+	.get = xattr_get,
+	.set = xattr_set,
 };
 
 static const struct xattr_handler ubifs_trusted_xattr_handler = {
 	.prefix = XATTR_TRUSTED_PREFIX,
-	.get = ubifs_xattr_get,
-	.set = ubifs_xattr_set,
+	.get = xattr_get,
+	.set = xattr_set,
 };
 
 static const struct xattr_handler ubifs_security_xattr_handler = {
 	.prefix = XATTR_SECURITY_PREFIX,
-	.get = ubifs_xattr_get,
-	.set = ubifs_xattr_set,
+	.get = xattr_get,
+	.set = xattr_set,
 };
 
 const struct xattr_handler *ubifs_xattr_handlers[] = {