[PATCH 06/26] ubifs: Add skeleton for fscrypto
Richard Weinberger
richard at nod.at
Fri Oct 21 05:48:21 PDT 2016
This is the first building block to provide file level
encryption on UBIFS.
Signed-off-by: Richard Weinberger <richard at nod.at>
---
fs/ubifs/Kconfig | 11 +++++++++++
fs/ubifs/Makefile | 1 +
fs/ubifs/crypto.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
fs/ubifs/dir.c | 28 +++++++++++++++++++++++++++-
fs/ubifs/ioctl.c | 35 +++++++++++++++++++++++++++++++++++
fs/ubifs/super.c | 10 ++++++++++
fs/ubifs/ubifs-media.h | 2 ++
fs/ubifs/ubifs.h | 39 ++++++++++++++++++++++++++++++++++++++-
fs/ubifs/xattr.c | 10 ++++++++++
9 files changed, 179 insertions(+), 2 deletions(-)
create mode 100644 fs/ubifs/crypto.c
diff --git a/fs/ubifs/Kconfig b/fs/ubifs/Kconfig
index 7ff7712f284e..0a908ae7af13 100644
--- a/fs/ubifs/Kconfig
+++ b/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.
diff --git a/fs/ubifs/Makefile b/fs/ubifs/Makefile
index c54a24360f85..6f3251c2bf08 100644
--- a/fs/ubifs/Makefile
+++ b/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
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
new file mode 100644
index 000000000000..160c31479e0c
--- /dev/null
+++ b/fs/ubifs/crypto.c
@@ -0,0 +1,45 @@
+#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;
+}
+
+struct fscrypt_operations ubifs_crypt_operations = {
+ .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,
+};
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 177343bce143..0e47127352ed 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -85,11 +85,26 @@ static int inherit_flags(const struct inode *dir, umode_t mode)
* initializes it. Returns new inode in case of success and an error code in
* case of failure.
*/
-struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
+struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
umode_t mode)
{
+ int err;
struct inode *inode;
struct ubifs_inode *ui;
+ bool encrypted = false;
+
+ if (ubifs_crypt_is_encrypted(dir)) {
+ err = fscrypt_get_encryption_info(dir);
+ if (err) {
+ ubifs_err(c, "fscrypt_get_encryption_info failed: %i", err);
+ return ERR_PTR(err);
+ }
+
+ if (!fscrypt_has_encryption_key(dir))
+ return ERR_PTR(-EPERM);
+
+ encrypted = true;
+ }
inode = new_inode(c->vfs_sb);
ui = ubifs_inode(inode);
@@ -165,6 +180,17 @@ struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
*/
ui->creat_sqnum = ++c->max_sqnum;
spin_unlock(&c->cnt_lock);
+
+ if (encrypted) {
+ err = fscrypt_inherit_context(dir, inode, &encrypted, true);
+ if (err) {
+ ubifs_err(c, "fscrypt_inherit_context failed: %i", err);
+ make_bad_inode(inode);
+ iput(inode);
+ return ERR_PTR(err);
+ }
+ }
+
return inode;
}
diff --git a/fs/ubifs/ioctl.c b/fs/ubifs/ioctl.c
index 3c7b29de0ca7..6bb5b35050de 100644
--- a/fs/ubifs/ioctl.c
+++ b/fs/ubifs/ioctl.c
@@ -181,6 +181,41 @@ 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 fscrypt_policy policy;
+
+ if (copy_from_user(&policy,
+ (struct fscrypt_policy __user *)arg,
+ sizeof(policy)))
+ return -EFAULT;
+
+ err = fscrypt_process_policy(file, &policy);
+
+ return err;
+#else
+ return -EOPNOTSUPP;
+#endif
+ }
+ case FS_IOC_GET_ENCRYPTION_POLICY: {
+#ifdef CONFIG_UBIFS_FS_ENCRYPTION
+ struct fscrypt_policy policy;
+
+ if (!ubifs_crypt_is_encrypted(inode))
+ return -ENOENT;
+
+ err = fscrypt_get_policy(inode, &policy);
+ if (err)
+ return err;
+
+ if (copy_to_user((void __user *)arg, &policy, sizeof(policy)))
+ return -EFAULT;
+
+ return 0;
+#else
+ return -EOPNOTSUPP;
+#endif
+ }
default:
return -ENOTTY;
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 4ec051089186..a31222947265 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -380,6 +380,9 @@ out:
}
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)
@@ -1995,6 +1998,12 @@ 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 +2050,7 @@ 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);
diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
index d47e9569b3de..aa302b11aec8 100644
--- a/fs/ubifs/ubifs-media.h
+++ b/fs/ubifs/ubifs-media.h
@@ -316,6 +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
@@ -328,6 +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 */
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 94c1f5563c01..63dd027727ca 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -38,6 +38,7 @@
#include <linux/backing-dev.h>
#include <linux/security.h>
#include <linux/xattr.h>
+#include <linux/fscrypto.h>
#include "ubifs-media.h"
/* Version of this UBIFS implementation */
@@ -1727,7 +1728,7 @@ int ubifs_update_time(struct inode *inode, struct timespec *time, int flags);
#endif
/* dir.c */
-struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
+struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
umode_t mode);
int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat);
@@ -1776,10 +1777,46 @@ void ubifs_compress(const struct ubifs_info *c, const void *in_buf, int in_len,
int ubifs_decompress(const struct ubifs_info *c, const void *buf, int len,
void *out, int *out_len, int compr_type);
+extern struct fscrypt_operations ubifs_crypt_operations;
+
#include "debug.h"
#include "misc.h"
#include "key.h"
+#ifndef CONFIG_UBIFS_FS_ENCRYPTION
+#define fscrypt_set_d_op(i)
+#define fscrypt_get_ctx fscrypt_notsupp_get_ctx
+#define fscrypt_release_ctx fscrypt_notsupp_release_ctx
+#define fscrypt_encrypt_page fscrypt_notsupp_encrypt_page
+#define fscrypt_decrypt_page fscrypt_notsupp_decrypt_page
+#define fscrypt_encrypt_buffer fscrypt_notsupp_encrypt_buffer
+#define fscrypt_decrypt_buffer fscrypt_notsupp_decrypt_buffer
+#define fscrypt_decrypt_bio_pages fscrypt_notsupp_decrypt_bio_pages
+#define fscrypt_pullback_bio_page fscrypt_notsupp_pullback_bio_page
+#define fscrypt_restore_control_page fscrypt_notsupp_restore_control_page
+#define fscrypt_zeroout_range fscrypt_notsupp_zeroout_range
+#define fscrypt_process_policy fscrypt_notsupp_process_policy
+#define fscrypt_get_policy fscrypt_notsupp_get_policy
+#define fscrypt_has_permitted_context fscrypt_notsupp_has_permitted_context
+#define fscrypt_inherit_context fscrypt_notsupp_inherit_context
+#define fscrypt_get_encryption_info fscrypt_notsupp_get_encryption_info
+#define fscrypt_put_encryption_info fscrypt_notsupp_put_encryption_info
+#define fscrypt_setup_filename fscrypt_notsupp_setup_filename
+#define fscrypt_free_filename fscrypt_notsupp_free_filename
+#define fscrypt_fname_encrypted_size fscrypt_notsupp_fname_encrypted_size
+#define fscrypt_fname_alloc_buffer fscrypt_notsupp_fname_alloc_buffer
+#define fscrypt_fname_free_buffer fscrypt_notsupp_fname_free_buffer
+#define fscrypt_fname_disk_to_usr fscrypt_notsupp_fname_disk_to_usr
+#define fscrypt_fname_usr_to_disk fscrypt_notsupp_fname_usr_to_disk
+#endif
+
+static inline bool ubifs_crypt_is_encrypted(struct inode *inode)
+{
+ struct ubifs_inode *ui = ubifs_inode(inode);
+
+ return ui->flags & UBIFS_CRYPT_FL;
+}
+
/* Normal UBIFS messages */
__printf(2, 3)
void ubifs_msg(const struct ubifs_info *c, const char *fmt, ...);
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index ad4463752709..b390902c48aa 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -158,6 +158,15 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
host_ui->xattr_size += CALC_XATTR_BYTES(size);
host_ui->xattr_names += nm->len;
+ /*
+ * 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(nm->name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
+ host_ui->flags |= UBIFS_CRYPT_FL;
+
err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
if (err)
goto out_cancel;
@@ -172,6 +181,7 @@ out_cancel:
host_ui->xattr_cnt -= 1;
host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
host_ui->xattr_size -= CALC_XATTR_BYTES(size);
+ host_ui->flags &= ~UBIFS_CRYPT_FL;
mutex_unlock(&host_ui->ui_mutex);
out_free:
make_bad_inode(inode);
--
2.7.3
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