diff options
Diffstat (limited to 'fs/ecryptfs/inode.c')
| -rw-r--r-- | fs/ecryptfs/inode.c | 1183 |
1 files changed, 1183 insertions, 0 deletions
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c new file mode 100644 index 000000000..525297c7e --- /dev/null +++ b/fs/ecryptfs/inode.c @@ -0,0 +1,1183 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * eCryptfs: Linux filesystem encryption layer + * + * Copyright (C) 1997-2004 Erez Zadok + * Copyright (C) 2001-2004 Stony Brook University + * Copyright (C) 2004-2007 International Business Machines Corp. + * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> + * Michael C. Thompsion <mcthomps@us.ibm.com> + */ + +#include <linux/file.h> +#include <linux/vmalloc.h> +#include <linux/pagemap.h> +#include <linux/dcache.h> +#include <linux/namei.h> +#include <linux/mount.h> +#include <linux/fs_stack.h> +#include <linux/slab.h> +#include <linux/xattr.h> +#include <linux/posix_acl.h> +#include <linux/posix_acl_xattr.h> +#include <linux/fileattr.h> +#include <linux/unaligned.h> +#include "ecryptfs_kernel.h" + +static struct dentry *ecryptfs_start_creating_dentry(struct dentry *dentry) +{ + struct dentry *parent = dget_parent(dentry); + struct dentry *ret; + + ret = start_creating_dentry(ecryptfs_dentry_to_lower(parent), + ecryptfs_dentry_to_lower(dentry)); + dput(parent); + return ret; +} + +static struct dentry *ecryptfs_start_removing_dentry(struct dentry *dentry) +{ + struct dentry *parent = dget_parent(dentry); + struct dentry *ret; + + ret = start_removing_dentry(ecryptfs_dentry_to_lower(parent), + ecryptfs_dentry_to_lower(dentry)); + dput(parent); + return ret; +} + +static int ecryptfs_inode_test(struct inode *inode, void *lower_inode) +{ + return ecryptfs_inode_to_lower(inode) == lower_inode; +} + +static int ecryptfs_inode_set(struct inode *inode, void *opaque) +{ + struct inode *lower_inode = opaque; + + ecryptfs_set_inode_lower(inode, lower_inode); + fsstack_copy_attr_all(inode, lower_inode); + /* i_size will be overwritten for encrypted regular files */ + fsstack_copy_inode_size(inode, lower_inode); + inode->i_ino = lower_inode->i_ino; + inode->i_mapping->a_ops = &ecryptfs_aops; + + if (S_ISLNK(inode->i_mode)) + inode->i_op = &ecryptfs_symlink_iops; + else if (S_ISDIR(inode->i_mode)) + inode->i_op = &ecryptfs_dir_iops; + else + inode->i_op = &ecryptfs_main_iops; + + if (S_ISDIR(inode->i_mode)) + inode->i_fop = &ecryptfs_dir_fops; + else if (special_file(inode->i_mode)) + init_special_inode(inode, inode->i_mode, inode->i_rdev); + else + inode->i_fop = &ecryptfs_main_fops; + + return 0; +} + +static struct inode *__ecryptfs_get_inode(struct inode *lower_inode, + struct super_block *sb) +{ + struct inode *inode; + + if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) + return ERR_PTR(-EXDEV); + + /* Reject dealing with casefold directories. */ + if (IS_CASEFOLDED(lower_inode)) { + pr_err_ratelimited("%s: Can't handle casefolded directory.\n", + __func__); + return ERR_PTR(-EREMOTE); + } + + if (!igrab(lower_inode)) + return ERR_PTR(-ESTALE); + inode = iget5_locked(sb, (unsigned long)lower_inode, + ecryptfs_inode_test, ecryptfs_inode_set, + lower_inode); + if (!inode) { + iput(lower_inode); + return ERR_PTR(-EACCES); + } + if (!(inode_state_read_once(inode) & I_NEW)) + iput(lower_inode); + + return inode; +} + +struct inode *ecryptfs_get_inode(struct inode *lower_inode, + struct super_block *sb) +{ + struct inode *inode = __ecryptfs_get_inode(lower_inode, sb); + + if (!IS_ERR(inode) && (inode_state_read_once(inode) & I_NEW)) + unlock_new_inode(inode); + + return inode; +} + +/** + * ecryptfs_interpose + * @lower_dentry: Existing dentry in the lower filesystem + * @dentry: ecryptfs' dentry + * @sb: ecryptfs's super_block + * + * Interposes upper and lower dentries. + * + * Returns zero on success; non-zero otherwise + */ +static int ecryptfs_interpose(struct dentry *lower_dentry, + struct dentry *dentry, struct super_block *sb) +{ + struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb); + + if (IS_ERR(inode)) + return PTR_ERR(inode); + d_instantiate(dentry, inode); + + return 0; +} + +static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry, + struct inode *inode) +{ + struct dentry *lower_dentry; + struct inode *lower_dir; + int rc; + + lower_dentry = ecryptfs_start_removing_dentry(dentry); + if (IS_ERR(lower_dentry)) + return PTR_ERR(lower_dentry); + + lower_dir = lower_dentry->d_parent->d_inode; + rc = vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry, NULL); + if (rc) { + printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); + goto out_unlock; + } + fsstack_copy_attr_times(dir, lower_dir); + set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink); + inode_set_ctime_to_ts(inode, inode_get_ctime(dir)); +out_unlock: + end_removing(lower_dentry); + if (!rc) + d_drop(dentry); + return rc; +} + +/** + * ecryptfs_do_create + * @directory_inode: inode of the new file's dentry's parent in ecryptfs + * @ecryptfs_dentry: New file's dentry in ecryptfs + * @mode: The mode of the new file + * + * Creates the underlying file and the eCryptfs inode which will link to + * it. It will also update the eCryptfs directory inode to mimic the + * stat of the lower directory inode. + * + * Returns the new eCryptfs inode on success; an ERR_PTR on error condition + */ +static struct inode * +ecryptfs_do_create(struct inode *directory_inode, + struct dentry *ecryptfs_dentry, umode_t mode) +{ + int rc; + struct dentry *lower_dentry; + struct inode *lower_dir; + struct inode *inode; + + lower_dentry = ecryptfs_start_creating_dentry(ecryptfs_dentry); + if (IS_ERR(lower_dentry)) + return ERR_CAST(lower_dentry); + lower_dir = lower_dentry->d_parent->d_inode; + rc = vfs_create(&nop_mnt_idmap, lower_dentry, mode, NULL); + if (rc) { + printk(KERN_ERR "%s: Failure to create dentry in lower fs; " + "rc = [%d]\n", __func__, rc); + inode = ERR_PTR(rc); + goto out_lock; + } + inode = __ecryptfs_get_inode(d_inode(lower_dentry), + directory_inode->i_sb); + if (IS_ERR(inode)) { + vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry, NULL); + goto out_lock; + } + fsstack_copy_attr_times(directory_inode, lower_dir); + fsstack_copy_inode_size(directory_inode, lower_dir); +out_lock: + end_creating(lower_dentry); + return inode; +} + +/* + * ecryptfs_initialize_file + * + * Cause the file to be changed from a basic empty file to an ecryptfs + * file with a header and first data page. + * + * Returns zero on success + */ +int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry, + struct inode *ecryptfs_inode) +{ + struct ecryptfs_crypt_stat *crypt_stat = + &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; + int rc = 0; + + if (S_ISDIR(ecryptfs_inode->i_mode)) { + ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); + crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); + goto out; + } + ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); + rc = ecryptfs_new_file_context(ecryptfs_inode); + if (rc) { + ecryptfs_printk(KERN_ERR, "Error creating new file " + "context; rc = [%d]\n", rc); + goto out; + } + rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the lower file for the dentry with name " + "[%pd]; rc = [%d]\n", __func__, + ecryptfs_dentry, rc); + goto out; + } + rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode); + if (rc) + printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); + ecryptfs_put_lower_file(ecryptfs_inode); +out: + return rc; +} + +/* + * ecryptfs_create + * @mode: The mode of the new file. + * + * Creates a new file. + * + * Returns zero on success; non-zero on error condition + */ +static int +ecryptfs_create(struct mnt_idmap *idmap, + struct inode *directory_inode, struct dentry *ecryptfs_dentry, + umode_t mode) +{ + struct inode *ecryptfs_inode; + int rc; + + ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry, + mode); + if (IS_ERR(ecryptfs_inode)) { + ecryptfs_printk(KERN_WARNING, "Failed to create file in" + "lower filesystem\n"); + rc = PTR_ERR(ecryptfs_inode); + goto out; + } + /* At this point, a file exists on "disk"; we need to make sure + * that this on disk file is prepared to be an ecryptfs file */ + rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode); + if (rc) { + ecryptfs_do_unlink(directory_inode, ecryptfs_dentry, + ecryptfs_inode); + iget_failed(ecryptfs_inode); + goto out; + } + d_instantiate_new(ecryptfs_dentry, ecryptfs_inode); +out: + return rc; +} + +static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode) +{ + struct ecryptfs_crypt_stat *crypt_stat; + int rc; + + rc = ecryptfs_get_lower_file(dentry, inode); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the lower file for the dentry with name " + "[%pd]; rc = [%d]\n", __func__, + dentry, rc); + return rc; + } + + crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; + /* TODO: lock for crypt_stat comparison */ + if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) + ecryptfs_set_default_sizes(crypt_stat); + + rc = ecryptfs_read_and_validate_header_region(inode); + ecryptfs_put_lower_file(inode); + if (rc) { + rc = ecryptfs_read_and_validate_xattr_region(dentry, inode); + if (!rc) + crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; + } + + /* Must return 0 to allow non-eCryptfs files to be looked up, too */ + return 0; +} + +/* + * ecryptfs_lookup_interpose - Dentry interposition for a lookup + */ +static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry, + struct dentry *lower_dentry) +{ + struct dentry *lower_parent = ecryptfs_dentry_to_lower(dentry->d_parent); + struct inode *inode, *lower_inode; + int rc = 0; + + fsstack_copy_attr_atime(d_inode(dentry->d_parent), + d_inode(lower_parent)); + BUG_ON(!d_count(lower_dentry)); + + ecryptfs_set_dentry_lower(dentry, lower_dentry); + + /* + * negative dentry can go positive under us here - its parent is not + * locked. That's OK and that could happen just as we return from + * ecryptfs_lookup() anyway. Just need to be careful and fetch + * ->d_inode only once - it's not stable here. + */ + lower_inode = READ_ONCE(lower_dentry->d_inode); + + if (!lower_inode) /* We want to add because we couldn't find in lower */ + return d_splice_alias(NULL, dentry); + + inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb); + if (IS_ERR(inode)) { + printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n", + __func__, PTR_ERR(inode)); + return ERR_CAST(inode); + } + if (S_ISREG(inode->i_mode)) { + rc = ecryptfs_i_size_read(dentry, inode); + if (rc) { + make_bad_inode(inode); + return ERR_PTR(rc); + } + } + + if (inode_state_read_once(inode) & I_NEW) + unlock_new_inode(inode); + return d_splice_alias(inode, dentry); +} + +/** + * ecryptfs_lookup + * @ecryptfs_dir_inode: The eCryptfs directory inode + * @ecryptfs_dentry: The eCryptfs dentry that we are looking up + * @flags: lookup flags + * + * Find a file on disk. If the file does not exist, then we'll add it to the + * dentry cache and continue on to read it from the disk. + */ +static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, + struct dentry *ecryptfs_dentry, + unsigned int flags) +{ + char *encrypted_and_encoded_name = NULL; + struct ecryptfs_mount_crypt_stat *mount_crypt_stat; + struct dentry *lower_dir_dentry, *lower_dentry; + struct qstr qname = QSTR_INIT(ecryptfs_dentry->d_name.name, + ecryptfs_dentry->d_name.len); + struct dentry *res; + int rc = 0; + + lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent); + + mount_crypt_stat = &ecryptfs_superblock_to_private( + ecryptfs_dentry->d_sb)->mount_crypt_stat; + if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { + size_t len = qname.len; + rc = ecryptfs_encrypt_and_encode_filename( + &encrypted_and_encoded_name, &len, + mount_crypt_stat, qname.name, len); + if (rc) { + printk(KERN_ERR "%s: Error attempting to encrypt and encode " + "filename; rc = [%d]\n", __func__, rc); + return ERR_PTR(rc); + } + qname.name = encrypted_and_encoded_name; + qname.len = len; + } + + lower_dentry = lookup_noperm_unlocked(&qname, lower_dir_dentry); + if (IS_ERR(lower_dentry)) { + ecryptfs_printk(KERN_DEBUG, "%s: lookup_noperm() returned " + "[%ld] on lower_dentry = [%s]\n", __func__, + PTR_ERR(lower_dentry), + qname.name); + res = ERR_CAST(lower_dentry); + } else { + res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry); + } + kfree(encrypted_and_encoded_name); + return res; +} + +static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *new_dentry) +{ + struct dentry *lower_old_dentry; + struct dentry *lower_new_dentry; + struct inode *lower_dir; + u64 file_size_save; + int rc; + + file_size_save = i_size_read(d_inode(old_dentry)); + lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); + lower_new_dentry = ecryptfs_start_creating_dentry(new_dentry); + if (IS_ERR(lower_new_dentry)) + return PTR_ERR(lower_new_dentry); + lower_dir = lower_new_dentry->d_parent->d_inode; + rc = vfs_link(lower_old_dentry, &nop_mnt_idmap, lower_dir, + lower_new_dentry, NULL); + if (rc || d_really_is_negative(lower_new_dentry)) + goto out_lock; + rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb); + if (rc) + goto out_lock; + fsstack_copy_attr_times(dir, lower_dir); + fsstack_copy_inode_size(dir, lower_dir); + set_nlink(d_inode(old_dentry), + ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink); + i_size_write(d_inode(new_dentry), file_size_save); +out_lock: + end_creating(lower_new_dentry); + return rc; +} + +static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) +{ + return ecryptfs_do_unlink(dir, dentry, d_inode(dentry)); +} + +static int ecryptfs_symlink(struct mnt_idmap *idmap, + struct inode *dir, struct dentry *dentry, + const char *symname) +{ + int rc; + struct dentry *lower_dentry; + struct inode *lower_dir; + char *encoded_symname; + size_t encoded_symlen; + struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; + + lower_dentry = ecryptfs_start_creating_dentry(dentry); + if (IS_ERR(lower_dentry)) + return PTR_ERR(lower_dentry); + lower_dir = lower_dentry->d_parent->d_inode; + + mount_crypt_stat = &ecryptfs_superblock_to_private( + dir->i_sb)->mount_crypt_stat; + rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname, + &encoded_symlen, + mount_crypt_stat, symname, + strlen(symname)); + if (rc) + goto out_lock; + rc = vfs_symlink(&nop_mnt_idmap, lower_dir, lower_dentry, + encoded_symname, NULL); + kfree(encoded_symname); + if (rc || d_really_is_negative(lower_dentry)) + goto out_lock; + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); + if (rc) + goto out_lock; + fsstack_copy_attr_times(dir, lower_dir); + fsstack_copy_inode_size(dir, lower_dir); +out_lock: + end_creating(lower_dentry); + if (d_really_is_negative(dentry)) + d_drop(dentry); + return rc; +} + +static struct dentry *ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + int rc; + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry; + struct inode *lower_dir; + + lower_dentry = ecryptfs_start_creating_dentry(dentry); + if (IS_ERR(lower_dentry)) + return lower_dentry; + lower_dir_dentry = dget(lower_dentry->d_parent); + lower_dir = lower_dir_dentry->d_inode; + lower_dentry = vfs_mkdir(&nop_mnt_idmap, lower_dir, + lower_dentry, mode, NULL); + rc = PTR_ERR(lower_dentry); + if (IS_ERR(lower_dentry)) + goto out; + rc = 0; + if (d_unhashed(lower_dentry)) + goto out; + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); + if (rc) + goto out; + fsstack_copy_attr_times(dir, lower_dir); + fsstack_copy_inode_size(dir, lower_dir); + set_nlink(dir, lower_dir->i_nlink); +out: + dput(lower_dir_dentry); + end_creating(lower_dentry); + if (d_really_is_negative(dentry)) + d_drop(dentry); + return ERR_PTR(rc); +} + +static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct dentry *lower_dentry; + struct inode *lower_dir; + int rc; + + lower_dentry = ecryptfs_start_removing_dentry(dentry); + if (IS_ERR(lower_dentry)) + return PTR_ERR(lower_dentry); + lower_dir = lower_dentry->d_parent->d_inode; + + rc = vfs_rmdir(&nop_mnt_idmap, lower_dir, lower_dentry, NULL); + if (!rc) { + clear_nlink(d_inode(dentry)); + fsstack_copy_attr_times(dir, lower_dir); + set_nlink(dir, lower_dir->i_nlink); + } + end_removing(lower_dentry); + if (!rc) + d_drop(dentry); + return rc; +} + +static int +ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode, dev_t dev) +{ + int rc; + struct dentry *lower_dentry; + struct inode *lower_dir; + + lower_dentry = ecryptfs_start_creating_dentry(dentry); + if (IS_ERR(lower_dentry)) + return PTR_ERR(lower_dentry); + lower_dir = lower_dentry->d_parent->d_inode; + + rc = vfs_mknod(&nop_mnt_idmap, lower_dir, lower_dentry, mode, dev, NULL); + if (rc || d_really_is_negative(lower_dentry)) + goto out; + rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); + if (rc) + goto out; + fsstack_copy_attr_times(dir, lower_dir); + fsstack_copy_inode_size(dir, lower_dir); +out: + end_creating(lower_dentry); + if (d_really_is_negative(dentry)) + d_drop(dentry); + return rc; +} + +static int +ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir, + struct dentry *old_dentry, struct inode *new_dir, + struct dentry *new_dentry, unsigned int flags) +{ + int rc; + struct dentry *lower_old_dentry; + struct dentry *lower_new_dentry; + struct dentry *lower_old_dir_dentry; + struct dentry *lower_new_dir_dentry; + struct inode *target_inode; + struct renamedata rd = {}; + + if (flags) + return -EINVAL; + + lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent); + lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent); + + lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); + lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); + + target_inode = d_inode(new_dentry); + + rd.mnt_idmap = &nop_mnt_idmap; + rd.old_parent = lower_old_dir_dentry; + rd.new_parent = lower_new_dir_dentry; + rc = start_renaming_two_dentries(&rd, lower_old_dentry, lower_new_dentry); + if (rc) + return rc; + + rc = vfs_rename(&rd); + if (rc) + goto out_lock; + if (target_inode) + fsstack_copy_attr_all(target_inode, + ecryptfs_inode_to_lower(target_inode)); + fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry)); + if (new_dir != old_dir) + fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry)); +out_lock: + end_renaming(&rd); + return rc; +} + +static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz) +{ + DEFINE_DELAYED_CALL(done); + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + const char *link; + char *buf; + int rc; + + link = vfs_get_link(lower_dentry, &done); + if (IS_ERR(link)) + return ERR_CAST(link); + + rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb, + link, strlen(link)); + do_delayed_call(&done); + if (rc) + return ERR_PTR(rc); + + return buf; +} + +static const char *ecryptfs_get_link(struct dentry *dentry, + struct inode *inode, + struct delayed_call *done) +{ + size_t len; + char *buf; + + if (!dentry) + return ERR_PTR(-ECHILD); + + buf = ecryptfs_readlink_lower(dentry, &len); + if (IS_ERR(buf)) + return buf; + fsstack_copy_attr_atime(d_inode(dentry), + d_inode(ecryptfs_dentry_to_lower(dentry))); + buf[len] = '\0'; + set_delayed_call(done, kfree_link, buf); + return buf; +} + +static void ecryptfs_iattr_to_lower(struct iattr *lower_ia, + const struct iattr *ia) +{ + memcpy(lower_ia, ia, sizeof(*lower_ia)); + if (ia->ia_valid & ATTR_FILE) + lower_ia->ia_file = ecryptfs_file_to_lower(ia->ia_file); + /* + * If the mode change is for clearing setuid/setgid bits, allow the lower + * file system to interpret this in its own way. + */ + if (lower_ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) + lower_ia->ia_valid &= ~ATTR_MODE; +} + +/** + * upper_size_to_lower_size + * @crypt_stat: Crypt_stat associated with file + * @upper_size: Size of the upper file + * + * Calculate the required size of the lower file based on the + * specified size of the upper file. This calculation is based on the + * number of headers in the underlying file and the extent size. + * + * Returns Calculated size of the lower file. + */ +static loff_t +upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, + loff_t upper_size) +{ + loff_t lower_size; + + lower_size = ecryptfs_lower_header_size(crypt_stat); + if (upper_size != 0) { + loff_t num_extents; + + num_extents = upper_size >> crypt_stat->extent_shift; + if (upper_size & ~crypt_stat->extent_mask) + num_extents++; + lower_size += (num_extents * crypt_stat->extent_size); + } + return lower_size; +} + +/** + * __ecryptfs_truncate + * @dentry: The ecryptfs layer dentry + * @ia: Address of the ecryptfs inode's attributes + * + * Handle truncations modifying the size of the file. Note that the file sizes + * are interpolated. When expanding, we are simply writing strings of 0's out. + * When truncating, we truncate the upper inode and update the lower_ia + * according to the page index interpolations. + * + * Returns zero on success; non-zero otherwise + */ +static int __ecryptfs_truncate(struct dentry *dentry, const struct iattr *ia) +{ + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + struct inode *inode = d_inode(dentry); + struct ecryptfs_crypt_stat *crypt_stat; + loff_t i_size = i_size_read(inode); + loff_t lower_size_before_truncate; + loff_t lower_size_after_truncate; + struct iattr lower_ia; + size_t num_zeros; + int rc; + + ecryptfs_iattr_to_lower(&lower_ia, ia); + + if (unlikely((ia->ia_size == i_size))) + return 0; + + crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; + lower_size_before_truncate = + upper_size_to_lower_size(crypt_stat, i_size); + lower_size_after_truncate = + upper_size_to_lower_size(crypt_stat, ia->ia_size); + if (lower_size_after_truncate > lower_size_before_truncate) { + /* + * The eCryptfs inode and the new *lower* size are mixed here + * because we may not have the lower i_mutex held and/or it may + * not be appropriate to call inode_newsize_ok() with inodes + * from other filesystems. + */ + rc = inode_newsize_ok(inode, lower_size_after_truncate); + if (rc) + return rc; + } + + rc = ecryptfs_get_lower_file(dentry, inode); + if (rc) + return rc; + + if (ia->ia_size > i_size) { + char zero[] = { 0x00 }; + + /* + * Write a single 0 at the last position of the file; this + * triggers code that will fill in 0's throughout the + * intermediate portion of the previous end of the file and the + * new end of the file. + */ + rc = ecryptfs_write(inode, zero, ia->ia_size - 1, 1); + goto out; + } + + if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { + truncate_setsize(inode, ia->ia_size); + lower_ia.ia_size = ia->ia_size; + goto set_size; + } + + /* + * We're chopping off all the pages down to the page in which + * ia->ia_size is located. Fill in the end of that page from + * (ia->ia_size & ~PAGE_MASK) to PAGE_SIZE with zeros. + */ + num_zeros = PAGE_SIZE - (ia->ia_size & ~PAGE_MASK); + if (num_zeros) { + rc = ecryptfs_write(inode, page_address(ZERO_PAGE(0)), + ia->ia_size, num_zeros); + if (rc) { + pr_err("Error attempting to zero out the remainder of the end page on reducing truncate; rc = [%d]\n", + rc); + goto out; + } + } + truncate_setsize(inode, ia->ia_size); + rc = ecryptfs_write_inode_size_to_metadata(inode); + if (rc) { + pr_err("Problem with ecryptfs_write_inode_size_to_metadata; rc = [%d]\n", + rc); + goto out; + } + + /* + * We are reducing the size of the ecryptfs file, and need to know if we + * need to reduce the size of the lower file. + */ + if (lower_size_after_truncate >= lower_size_before_truncate) + goto out; + + lower_ia.ia_size = lower_size_after_truncate; +set_size: + lower_ia.ia_valid |= ATTR_SIZE; + inode_lock(d_inode(lower_dentry)); + rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, NULL); + inode_unlock(d_inode(lower_dentry)); +out: + ecryptfs_put_lower_file(inode); + return rc; +} + +/** + * ecryptfs_truncate + * @dentry: The ecryptfs layer dentry + * @new_length: The length to expand the file to + * + * Simple function that handles the truncation of an eCryptfs inode and + * its corresponding lower inode. + * + * Returns zero on success; non-zero otherwise + */ +int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) +{ + const struct iattr ia = { + .ia_valid = ATTR_SIZE, + .ia_size = new_length, + }; + + return __ecryptfs_truncate(dentry, &ia); +} + +static int +ecryptfs_permission(struct mnt_idmap *idmap, struct inode *inode, + int mask) +{ + return inode_permission(&nop_mnt_idmap, + ecryptfs_inode_to_lower(inode), mask); +} + +/** + * ecryptfs_setattr + * @idmap: idmap of the target mount + * @dentry: dentry handle to the inode to modify + * @ia: Structure with flags of what to change and values + * + * Updates the metadata of an inode. If the update is to the size + * i.e. truncation, then ecryptfs_truncate will handle the size modification + * of both the ecryptfs inode and the lower inode. + * + * All other metadata changes will be passed right to the lower filesystem, + * and we will just update our inode to look like the lower. + */ +static int ecryptfs_setattr(struct mnt_idmap *idmap, + struct dentry *dentry, struct iattr *ia) +{ + struct inode *inode = d_inode(dentry); + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + struct inode *lower_inode = ecryptfs_inode_to_lower(inode); + struct ecryptfs_crypt_stat *crypt_stat; + int rc; + + crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat; + if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) + ecryptfs_init_crypt_stat(crypt_stat); + + mutex_lock(&crypt_stat->cs_mutex); + if (d_is_dir(dentry)) + crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); + else if (d_is_reg(dentry) && + (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) || + !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { + struct ecryptfs_mount_crypt_stat *mount_crypt_stat; + + mount_crypt_stat = &ecryptfs_superblock_to_private( + dentry->d_sb)->mount_crypt_stat; + rc = ecryptfs_get_lower_file(dentry, inode); + if (rc) { + mutex_unlock(&crypt_stat->cs_mutex); + goto out; + } + rc = ecryptfs_read_metadata(dentry); + ecryptfs_put_lower_file(inode); + if (rc) { + if (!(mount_crypt_stat->flags & + ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { + rc = -EIO; + printk(KERN_WARNING "Either the lower file " + "is not in a valid eCryptfs format, " + "or the key could not be retrieved. " + "Plaintext passthrough mode is not " + "enabled; returning -EIO\n"); + mutex_unlock(&crypt_stat->cs_mutex); + goto out; + } + rc = 0; + crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED + | ECRYPTFS_ENCRYPTED); + } + } + mutex_unlock(&crypt_stat->cs_mutex); + + rc = setattr_prepare(&nop_mnt_idmap, dentry, ia); + if (rc) + goto out; + + if (ia->ia_valid & ATTR_SIZE) { + rc = __ecryptfs_truncate(dentry, ia); + } else { + struct iattr lower_ia; + + ecryptfs_iattr_to_lower(&lower_ia, ia); + + inode_lock(d_inode(lower_dentry)); + rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, + NULL); + inode_unlock(d_inode(lower_dentry)); + } +out: + fsstack_copy_attr_all(inode, lower_inode); + return rc; +} + +static int ecryptfs_getattr_link(struct mnt_idmap *idmap, + const struct path *path, struct kstat *stat, + u32 request_mask, unsigned int flags) +{ + struct dentry *dentry = path->dentry; + struct ecryptfs_mount_crypt_stat *mount_crypt_stat; + int rc = 0; + + mount_crypt_stat = &ecryptfs_superblock_to_private( + dentry->d_sb)->mount_crypt_stat; + generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat); + if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { + char *target; + size_t targetsiz; + + target = ecryptfs_readlink_lower(dentry, &targetsiz); + if (!IS_ERR(target)) { + kfree(target); + stat->size = targetsiz; + } else { + rc = PTR_ERR(target); + } + } + return rc; +} + +static int ecryptfs_getattr(struct mnt_idmap *idmap, + const struct path *path, struct kstat *stat, + u32 request_mask, unsigned int flags) +{ + struct dentry *dentry = path->dentry; + struct kstat lower_stat; + struct path lower_path = ecryptfs_lower_path(dentry); + int rc; + + rc = vfs_getattr_nosec(&lower_path, &lower_stat, request_mask, flags); + if (!rc) { + fsstack_copy_attr_all(d_inode(dentry), + ecryptfs_inode_to_lower(d_inode(dentry))); + generic_fillattr(&nop_mnt_idmap, request_mask, + d_inode(dentry), stat); + stat->blocks = lower_stat.blocks; + } + return rc; +} + +int +ecryptfs_setxattr(struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + int rc; + struct dentry *lower_dentry; + struct inode *lower_inode; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + lower_inode = d_inode(lower_dentry); + if (!(lower_inode->i_opflags & IOP_XATTR)) { + rc = -EOPNOTSUPP; + goto out; + } + inode_lock(lower_inode); + rc = __vfs_setxattr_locked(&nop_mnt_idmap, lower_dentry, name, value, size, flags, NULL); + inode_unlock(lower_inode); + if (!rc && inode) + fsstack_copy_attr_all(inode, lower_inode); +out: + return rc; +} + +ssize_t +ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode, + const char *name, void *value, size_t size) +{ + int rc; + + if (!(lower_inode->i_opflags & IOP_XATTR)) { + rc = -EOPNOTSUPP; + goto out; + } + inode_lock(lower_inode); + rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size); + inode_unlock(lower_inode); +out: + return rc; +} + +static ssize_t +ecryptfs_getxattr(struct dentry *dentry, struct inode *inode, + const char *name, void *value, size_t size) +{ + return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), + ecryptfs_inode_to_lower(inode), + name, value, size); +} + +static ssize_t +ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) +{ + int rc = 0; + struct dentry *lower_dentry; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + if (!d_inode(lower_dentry)->i_op->listxattr) { + rc = -EOPNOTSUPP; + goto out; + } + inode_lock(d_inode(lower_dentry)); + rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size); + inode_unlock(d_inode(lower_dentry)); +out: + return rc; +} + +static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode, + const char *name) +{ + int rc; + struct dentry *lower_dentry; + struct inode *lower_inode; + + lower_dentry = ecryptfs_dentry_to_lower(dentry); + lower_inode = ecryptfs_inode_to_lower(inode); + if (!(lower_inode->i_opflags & IOP_XATTR)) { + rc = -EOPNOTSUPP; + goto out; + } + inode_lock(lower_inode); + rc = __vfs_removexattr(&nop_mnt_idmap, lower_dentry, name); + inode_unlock(lower_inode); +out: + return rc; +} + +static int ecryptfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa) +{ + return vfs_fileattr_get(ecryptfs_dentry_to_lower(dentry), fa); +} + +static int ecryptfs_fileattr_set(struct mnt_idmap *idmap, + struct dentry *dentry, struct file_kattr *fa) +{ + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + int rc; + + rc = vfs_fileattr_set(&nop_mnt_idmap, lower_dentry, fa); + fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry)); + + return rc; +} + +static struct posix_acl *ecryptfs_get_acl(struct mnt_idmap *idmap, + struct dentry *dentry, int type) +{ + return vfs_get_acl(idmap, ecryptfs_dentry_to_lower(dentry), + posix_acl_xattr_name(type)); +} + +static int ecryptfs_set_acl(struct mnt_idmap *idmap, + struct dentry *dentry, struct posix_acl *acl, + int type) +{ + int rc; + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + struct inode *lower_inode = d_inode(lower_dentry); + + rc = vfs_set_acl(&nop_mnt_idmap, lower_dentry, + posix_acl_xattr_name(type), acl); + if (!rc) + fsstack_copy_attr_all(d_inode(dentry), lower_inode); + return rc; +} + +const struct inode_operations ecryptfs_symlink_iops = { + .get_link = ecryptfs_get_link, + .permission = ecryptfs_permission, + .setattr = ecryptfs_setattr, + .getattr = ecryptfs_getattr_link, + .listxattr = ecryptfs_listxattr, +}; + +const struct inode_operations ecryptfs_dir_iops = { + .create = ecryptfs_create, + .lookup = ecryptfs_lookup, + .link = ecryptfs_link, + .unlink = ecryptfs_unlink, + .symlink = ecryptfs_symlink, + .mkdir = ecryptfs_mkdir, + .rmdir = ecryptfs_rmdir, + .mknod = ecryptfs_mknod, + .rename = ecryptfs_rename, + .permission = ecryptfs_permission, + .setattr = ecryptfs_setattr, + .listxattr = ecryptfs_listxattr, + .fileattr_get = ecryptfs_fileattr_get, + .fileattr_set = ecryptfs_fileattr_set, + .get_acl = ecryptfs_get_acl, + .set_acl = ecryptfs_set_acl, +}; + +const struct inode_operations ecryptfs_main_iops = { + .permission = ecryptfs_permission, + .setattr = ecryptfs_setattr, + .getattr = ecryptfs_getattr, + .listxattr = ecryptfs_listxattr, + .fileattr_get = ecryptfs_fileattr_get, + .fileattr_set = ecryptfs_fileattr_set, + .get_acl = ecryptfs_get_acl, + .set_acl = ecryptfs_set_acl, +}; + +static int ecryptfs_xattr_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + return ecryptfs_getxattr(dentry, inode, name, buffer, size); +} + +static int ecryptfs_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, size_t size, + int flags) +{ + if (value) + return ecryptfs_setxattr(dentry, inode, name, value, size, flags); + else { + BUG_ON(flags != XATTR_REPLACE); + return ecryptfs_removexattr(dentry, inode, name); + } +} + +static const struct xattr_handler ecryptfs_xattr_handler = { + .prefix = "", /* match anything */ + .get = ecryptfs_xattr_get, + .set = ecryptfs_xattr_set, +}; + +const struct xattr_handler * const ecryptfs_xattr_handlers[] = { + &ecryptfs_xattr_handler, + NULL +}; |