[PATCH 20/26] ubifs: Add support for encrypted symlinks
From: Richard Weinberger
Date: Fri Oct 21 2016 - 08:55:30 EST
Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
fs/ubifs/dir.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++-------
fs/ubifs/file.c | 55 +++++++++++++++++++++++++++++++++++++-
fs/ubifs/super.c | 1 -
3 files changed, 125 insertions(+), 12 deletions(-)
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 723bae4dec30..2f33be5ca57c 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1051,10 +1051,27 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
struct ubifs_inode *dir_ui = ubifs_inode(dir);
struct ubifs_info *c = dir->i_sb->s_fs_info;
int err, len = strlen(symname);
- int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
+ int sz_change = CALC_DENT_SIZE(len);
+ struct fscrypt_str disk_link = FSTR_INIT((char *)symname, len + 1);
+ struct fscrypt_symlink_data *sd = NULL;
struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
.new_ino_d = ALIGN(len, 8),
.dirtied_ino = 1 };
+ struct fscrypt_name nm;
+
+ if (ubifs_crypt_is_encrypted(dir)) {
+ err = fscrypt_get_encryption_info(dir);
+ if (err)
+ goto out_budg;
+
+ if (!fscrypt_has_encryption_key(dir)) {
+ err = -EPERM;
+ goto out_budg;
+ }
+
+ disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
+ sizeof(struct fscrypt_symlink_data));
+ }
/*
* Budget request settings: new inode, new direntry and changing parent
@@ -1064,36 +1081,77 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
dbg_gen("dent '%pd', target '%s' in dir ino %lu", dentry,
symname, dir->i_ino);
- if (len > UBIFS_MAX_INO_DATA)
+ if (disk_link.len > UBIFS_MAX_INO_DATA)
return -ENAMETOOLONG;
err = ubifs_budget_space(c, &req);
if (err)
return err;
+ err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+ if (err)
+ goto out_budg;
+
inode = ubifs_new_inode(c, dir, S_IFLNK | S_IRWXUGO);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
- goto out_budg;
+ goto out_fname;
}
ui = ubifs_inode(inode);
- ui->data = kmalloc(len + 1, GFP_NOFS);
+ ui->data = kmalloc(disk_link.len, GFP_NOFS);
if (!ui->data) {
err = -ENOMEM;
goto out_inode;
}
- memcpy(ui->data, symname, len);
- ((char *)ui->data)[len] = '\0';
- inode->i_link = ui->data;
+ if (ubifs_crypt_is_encrypted(dir)) {
+ struct qstr istr = QSTR_INIT(symname, len);
+ struct fscrypt_str ostr;
+
+ sd = kzalloc(disk_link.len, GFP_NOFS);
+ if (!sd) {
+ err = -ENOMEM;
+ goto out_inode;
+ }
+
+ err = fscrypt_get_encryption_info(inode);
+ if (err) {
+ kfree(sd);
+ goto out_inode;
+ }
+
+ if (!fscrypt_has_encryption_key(inode)) {
+ kfree(sd);
+ err = -EPERM;
+ goto out_inode;
+ }
+
+ ostr.name = sd->encrypted_path;
+ ostr.len = disk_link.len;
+
+ err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);
+ if (err < 0) {
+ kfree(sd);
+ goto out_inode;
+ }
+
+ sd->len = cpu_to_le16(ostr.len);
+ disk_link.name = (char *)sd;
+ } else {
+ inode->i_link = ui->data;
+ }
+
+ memcpy(ui->data, disk_link.name, disk_link.len);
+ ((char *)ui->data)[disk_link.len - 1] = '\0';
+
/*
* The terminating zero byte is not written to the flash media and it
* is put just to make later in-memory string processing simpler. Thus,
* data length is @len, not @len + %1.
*/
- ui->data_len = len;
- inode->i_size = ubifs_inode(inode)->ui_size = len;
+ ui->data_len = disk_link.len - 1;
+ inode->i_size = ubifs_inode(inode)->ui_size = disk_link.len - 1;
err = ubifs_init_security(dir, inode, &dentry->d_name);
if (err)
@@ -1103,7 +1161,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
dir->i_size += sz_change;
dir_ui->ui_size = dir->i_size;
dir->i_mtime = dir->i_ctime = inode->i_ctime;
- err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
+ err = ubifs_jnl_update(c, dir, &nm, inode, 0, 0);
if (err)
goto out_cancel;
mutex_unlock(&dir_ui->ui_mutex);
@@ -1111,6 +1169,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
ubifs_release_budget(c, &req);
insert_inode_hash(inode);
d_instantiate(dentry, inode);
+ fscrypt_free_filename(&nm);
return 0;
out_cancel:
@@ -1120,6 +1179,8 @@ out_cancel:
out_inode:
make_bad_inode(inode);
iput(inode);
+out_fname:
+ fscrypt_free_filename(&nm);
out_budg:
ubifs_release_budget(c, &req);
return err;
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 60e089d50c82..ce168b3f61ca 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1679,6 +1679,59 @@ static int ubifs_file_open(struct inode *inode, struct file *filp)
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 (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ if (ubifs_crypt_is_encrypted(inode)) {
+ err = fscrypt_get_encryption_info(inode);
+ if (err)
+ return ERR_PTR(err);
+ } else
+ return ui->data;
+
+
+ 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 < 0) {
+ fscrypt_fname_free_buffer(&pstr);
+ return ERR_PTR(err);
+ }
+
+ pstr.name[err] = '\0';
+
+ 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,
@@ -1706,7 +1759,7 @@ 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,
.setxattr = generic_setxattr,
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index ae25c908fbe5..e08aa04fc835 100644
--- a/fs/ubifs/super.c
+++ b/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:
--
2.7.3