From cbaf042a3cc6c37f9005fd6952cbf2013ab7cc15 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 29 Apr 2015 15:10:53 -0700 Subject: [PATCH] f2fs crypto: add symlink encryption This patch implements encryption support for symlink. Signed-off-by: Uday Savagaonkar Signed-off-by: Theodore Ts'o Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 1 + fs/f2fs/inode.c | 5 +- fs/f2fs/namei.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 142 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index ea4f48f3073c..20e7be613d1e 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1920,6 +1920,7 @@ extern const struct address_space_operations f2fs_node_aops; extern const struct address_space_operations f2fs_meta_aops; extern const struct inode_operations f2fs_dir_inode_operations; extern const struct inode_operations f2fs_symlink_inode_operations; +extern const struct inode_operations f2fs_encrypted_symlink_inode_operations; extern const struct inode_operations f2fs_special_inode_operations; extern struct kmem_cache *inode_entry_slab; diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 00f0e74176cb..ea6ba3bc8472 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -198,7 +198,10 @@ make_now: inode->i_mapping->a_ops = &f2fs_dblock_aops; mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_HIGH_ZERO); } else if (S_ISLNK(inode->i_mode)) { - inode->i_op = &f2fs_symlink_inode_operations; + if (f2fs_encrypted_inode(inode)) + inode->i_op = &f2fs_encrypted_symlink_inode_operations; + else + inode->i_op = &f2fs_symlink_inode_operations; inode->i_mapping->a_ops = &f2fs_dblock_aops; } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index c857f8249da0..bbd83e427834 100644 --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -338,16 +338,26 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, { struct f2fs_sb_info *sbi = F2FS_I_SB(dir); struct inode *inode; - size_t symlen = strlen(symname) + 1; + size_t len = strlen(symname); + size_t p_len; + char *p_str; + struct f2fs_str disk_link = FSTR_INIT(NULL, 0); + struct f2fs_encrypted_symlink_data *sd = NULL; int err; + if (len > dir->i_sb->s_blocksize) + return -ENAMETOOLONG; + f2fs_balance_fs(sbi); inode = f2fs_new_inode(dir, S_IFLNK | S_IRWXUGO); if (IS_ERR(inode)) return PTR_ERR(inode); - inode->i_op = &f2fs_symlink_inode_operations; + if (f2fs_encrypted_inode(inode)) + inode->i_op = &f2fs_encrypted_symlink_inode_operations; + else + inode->i_op = &f2fs_symlink_inode_operations; inode->i_mapping->a_ops = &f2fs_dblock_aops; f2fs_lock_op(sbi); @@ -355,10 +365,50 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, if (err) goto out; f2fs_unlock_op(sbi); - - err = page_symlink(inode, symname, symlen); alloc_nid_done(sbi, inode->i_ino); + if (f2fs_encrypted_inode(dir)) { + struct qstr istr = QSTR_INIT(symname, len); + + err = f2fs_inherit_context(dir, inode, NULL); + if (err) + goto err_out; + + err = f2fs_setup_fname_crypto(inode); + if (err) + goto err_out; + + err = f2fs_fname_crypto_alloc_buffer(inode, len, &disk_link); + if (err) + goto err_out; + + err = f2fs_fname_usr_to_disk(inode, &istr, &disk_link); + if (err < 0) + goto err_out; + + p_len = encrypted_symlink_data_len(disk_link.len) + 1; + + if (p_len > dir->i_sb->s_blocksize) { + err = -ENAMETOOLONG; + goto err_out; + } + + sd = kzalloc(p_len, GFP_NOFS); + if (!sd) { + err = -ENOMEM; + goto err_out; + } + memcpy(sd->encrypted_path, disk_link.name, disk_link.len); + sd->len = cpu_to_le16(disk_link.len); + p_str = (char *)sd; + } else { + p_len = len + 1; + p_str = (char *)symname; + } + + err = page_symlink(inode, p_str, p_len); + +err_out: d_instantiate(dentry, inode); unlock_new_inode(inode); @@ -371,10 +421,14 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, * If the symlink path is stored into inline_data, there is no * performance regression. */ - filemap_write_and_wait_range(inode->i_mapping, 0, symlen - 1); + if (!err) + filemap_write_and_wait_range(inode->i_mapping, 0, p_len - 1); if (IS_DIRSYNC(dir)) f2fs_sync_fs(sbi->sb, 1); + + kfree(sd); + f2fs_fname_crypto_free_buffer(&disk_link); return err; out: handle_failed_inode(inode); @@ -818,6 +872,84 @@ out: return err; } +#ifdef CONFIG_F2FS_FS_ENCRYPTION +static void *f2fs_encrypted_follow_link(struct dentry *dentry, + struct nameidata *nd) +{ + struct page *cpage = NULL; + char *caddr, *paddr = NULL; + struct f2fs_str cstr; + struct f2fs_str pstr = FSTR_INIT(NULL, 0); + struct inode *inode = d_inode(dentry); + struct f2fs_encrypted_symlink_data *sd; + loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1); + u32 max_size = inode->i_sb->s_blocksize; + int res; + + res = f2fs_setup_fname_crypto(inode); + if (res) + return ERR_PTR(res); + + cpage = read_mapping_page(inode->i_mapping, 0, NULL); + if (IS_ERR(cpage)) + return cpage; + caddr = kmap(cpage); + caddr[size] = 0; + + /* Symlink is encrypted */ + sd = (struct f2fs_encrypted_symlink_data *)caddr; + cstr.name = sd->encrypted_path; + cstr.len = le16_to_cpu(sd->len); + + /* this is broken symlink case */ + if (cstr.name[0] == 0 && cstr.len == 0) { + res = -ENOENT; + goto errout; + } + + if ((cstr.len + sizeof(struct f2fs_encrypted_symlink_data) - 1) > + max_size) { + /* Symlink data on the disk is corrupted */ + res = -EIO; + goto errout; + } + res = f2fs_fname_crypto_alloc_buffer(inode, cstr.len, &pstr); + if (res) + goto errout; + + res = f2fs_fname_disk_to_usr(inode, NULL, &cstr, &pstr); + if (res < 0) + goto errout; + + paddr = pstr.name; + + /* Null-terminate the name */ + paddr[res] = '\0'; + nd_set_link(nd, paddr); + + kunmap(cpage); + page_cache_release(cpage); + return NULL; +errout: + f2fs_fname_crypto_free_buffer(&pstr); + kunmap(cpage); + page_cache_release(cpage); + return ERR_PTR(res); +} + +const struct inode_operations f2fs_encrypted_symlink_inode_operations = { + .readlink = generic_readlink, + .follow_link = f2fs_encrypted_follow_link, + .put_link = kfree_put_link, + .getattr = f2fs_getattr, + .setattr = f2fs_setattr, + .setxattr = generic_setxattr, + .getxattr = generic_getxattr, + .listxattr = f2fs_listxattr, + .removexattr = generic_removexattr, +}; +#endif + const struct inode_operations f2fs_dir_inode_operations = { .create = f2fs_create, .lookup = f2fs_lookup, -- 2.20.1