/** * 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> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA * 02111-1307, USA. */ #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 <asm/unaligned.h> #include "ecryptfs_kernel.h" static struct dentry *lock_parent(struct dentry *dentry) { struct dentry *dir; dir = dget_parent(dentry); inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); return dir; } static void unlock_dir(struct dentry *dir) { inode_unlock(d_inode(dir)); dput(dir); } 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_version++; 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); 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->i_state & 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->i_state & 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 = ecryptfs_dentry_to_lower(dentry); struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); struct dentry *lower_dir_dentry; int rc; dget(lower_dentry); lower_dir_dentry = lock_parent(lower_dentry); rc = vfs_unlink(lower_dir_inode, 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_inode); set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink); inode->i_ctime = dir->i_ctime; d_drop(dentry); out_unlock: unlock_dir(lower_dir_dentry); dput(lower_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 dentry *lower_dir_dentry; struct inode *inode; lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); lower_dir_dentry = lock_parent(lower_dentry); rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true); 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(d_inode(lower_dir_dentry), lower_dentry, NULL); goto out_lock; } fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry)); fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry)); out_lock: unlock_dir(lower_dir_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 * @dir: The inode of the directory in which to create the file. * @dentry: The eCryptfs dentry * @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 inode *directory_inode, struct dentry *ecryptfs_dentry, umode_t mode, bool excl) { 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; } unlock_new_inode(ecryptfs_inode); d_instantiate(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 inode *inode, *lower_inode = d_inode(lower_dentry); struct ecryptfs_dentry_info *dentry_info; struct vfsmount *lower_mnt; int rc = 0; dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL); if (!dentry_info) { printk(KERN_ERR "%s: Out of memory whilst attempting " "to allocate ecryptfs_dentry_info struct\n", __func__); dput(lower_dentry); return ERR_PTR(-ENOMEM); } lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); fsstack_copy_attr_atime(d_inode(dentry->d_parent), d_inode(lower_dentry->d_parent)); BUG_ON(!d_count(lower_dentry)); ecryptfs_set_dentry_private(dentry, dentry_info); dentry_info->lower_path.mnt = lower_mnt; dentry_info->lower_path.dentry = lower_dentry; if (d_really_is_negative(lower_dentry)) { /* We want to add because we couldn't find in lower */ d_add(dentry, NULL); return NULL; } 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->i_state & 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; const char *name = ecryptfs_dentry->d_name.name; size_t len = 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 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { rc = ecryptfs_encrypt_and_encode_filename( &encrypted_and_encoded_name, &len, mount_crypt_stat, name, len); if (rc) { printk(KERN_ERR "%s: Error attempting to encrypt and encode " "filename; rc = [%d]\n", __func__, rc); return ERR_PTR(rc); } name = encrypted_and_encoded_name; } lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len); if (IS_ERR(lower_dentry)) { ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned " "[%ld] on lower_dentry = [%s]\n", __func__, PTR_ERR(lower_dentry), 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 dentry *lower_dir_dentry; 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_dentry_to_lower(new_dentry); dget(lower_old_dentry); dget(lower_new_dentry); lower_dir_dentry = lock_parent(lower_new_dentry); rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry), 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, d_inode(lower_dir_dentry)); fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); 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: unlock_dir(lower_dir_dentry); dput(lower_new_dentry); dput(lower_old_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 inode *dir, struct dentry *dentry, const char *symname) { int rc; struct dentry *lower_dentry; struct dentry *lower_dir_dentry; char *encoded_symname; size_t encoded_symlen; struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; lower_dentry = ecryptfs_dentry_to_lower(dentry); dget(lower_dentry); lower_dir_dentry = lock_parent(lower_dentry); 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(d_inode(lower_dir_dentry), lower_dentry, encoded_symname); 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, d_inode(lower_dir_dentry)); fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); out_lock: unlock_dir(lower_dir_dentry); dput(lower_dentry); if (d_really_is_negative(dentry)) d_drop(dentry); return rc; } static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { int rc; struct dentry *lower_dentry; struct dentry *lower_dir_dentry; lower_dentry = ecryptfs_dentry_to_lower(dentry); lower_dir_dentry = lock_parent(lower_dentry); rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode); 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, d_inode(lower_dir_dentry)); fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink); out: unlock_dir(lower_dir_dentry); if (d_really_is_negative(dentry)) d_drop(dentry); return rc; } static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) { struct dentry *lower_dentry; struct dentry *lower_dir_dentry; int rc; lower_dentry = ecryptfs_dentry_to_lower(dentry); dget(dentry); lower_dir_dentry = lock_parent(lower_dentry); dget(lower_dentry); rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry); dput(lower_dentry); if (!rc && d_really_is_positive(dentry)) clear_nlink(d_inode(dentry)); fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry)); set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink); unlock_dir(lower_dir_dentry); if (!rc) d_drop(dentry); dput(dentry); return rc; } static int ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { int rc; struct dentry *lower_dentry; struct dentry *lower_dir_dentry; lower_dentry = ecryptfs_dentry_to_lower(dentry); lower_dir_dentry = lock_parent(lower_dentry); rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev); 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, d_inode(lower_dir_dentry)); fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); out: unlock_dir(lower_dir_dentry); if (d_really_is_negative(dentry)) d_drop(dentry); return rc; } static int ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) { 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 dentry *trap = NULL; struct inode *target_inode; lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); dget(lower_old_dentry); dget(lower_new_dentry); lower_old_dir_dentry = dget_parent(lower_old_dentry); lower_new_dir_dentry = dget_parent(lower_new_dentry); target_inode = d_inode(new_dentry); trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); /* source should not be ancestor of target */ if (trap == lower_old_dentry) { rc = -EINVAL; goto out_lock; } /* target should not be ancestor of source */ if (trap == lower_new_dentry) { rc = -ENOTEMPTY; goto out_lock; } rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry, d_inode(lower_new_dir_dentry), lower_new_dentry, NULL, 0); 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: unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); dput(lower_new_dir_dentry); dput(lower_old_dir_dentry); dput(lower_new_dentry); dput(lower_old_dentry); return rc; } static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz) { struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); char *lower_buf; char *buf; mm_segment_t old_fs; int rc; lower_buf = kmalloc(PATH_MAX, GFP_KERNEL); if (!lower_buf) return ERR_PTR(-ENOMEM); old_fs = get_fs(); set_fs(get_ds()); rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry, (char __user *)lower_buf, PATH_MAX); set_fs(old_fs); if (rc < 0) goto out; rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb, lower_buf, rc); out: kfree(lower_buf); return rc ? ERR_PTR(rc) : 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; } /** * 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; } /** * truncate_upper * @dentry: The ecryptfs layer dentry * @ia: Address of the ecryptfs inode's attributes * @lower_ia: Address of the lower inode's attributes * * Function to 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. If ATTR_SIZE is set in lower_ia->ia_valid upon return, * the caller must use lower_ia in a call to notify_change() to perform * the truncation of the lower inode. * * Returns zero on success; non-zero otherwise */ static int truncate_upper(struct dentry *dentry, struct iattr *ia, struct iattr *lower_ia) { int rc = 0; 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; if (unlikely((ia->ia_size == i_size))) { lower_ia->ia_valid &= ~ATTR_SIZE; return 0; } rc = ecryptfs_get_lower_file(dentry, inode); if (rc) return rc; crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat; /* Switch on growing or shrinking file */ if (ia->ia_size > i_size) { char zero[] = { 0x00 }; lower_ia->ia_valid &= ~ATTR_SIZE; /* 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 and of the file */ rc = ecryptfs_write(inode, zero, (ia->ia_size - 1), 1); } else { /* ia->ia_size < i_size_read(inode) */ /* 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. */ size_t num_zeros = (PAGE_SIZE - (ia->ia_size & ~PAGE_MASK)); if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { truncate_setsize(inode, ia->ia_size); lower_ia->ia_size = ia->ia_size; lower_ia->ia_valid |= ATTR_SIZE; goto out; } if (num_zeros) { char *zeros_virt; zeros_virt = kzalloc(num_zeros, GFP_KERNEL); if (!zeros_virt) { rc = -ENOMEM; goto out; } rc = ecryptfs_write(inode, zeros_virt, ia->ia_size, num_zeros); kfree(zeros_virt); if (rc) { printk(KERN_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) { printk(KERN_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. */ 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) { lower_ia->ia_size = lower_size_after_truncate; lower_ia->ia_valid |= ATTR_SIZE; } else lower_ia->ia_valid &= ~ATTR_SIZE; } out: ecryptfs_put_lower_file(inode); return rc; } static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset) { struct ecryptfs_crypt_stat *crypt_stat; loff_t lower_oldsize, lower_newsize; crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; lower_oldsize = upper_size_to_lower_size(crypt_stat, i_size_read(inode)); lower_newsize = upper_size_to_lower_size(crypt_stat, offset); if (lower_newsize > lower_oldsize) { /* * 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. */ return inode_newsize_ok(inode, lower_newsize); } return 0; } /** * 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) { struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length }; struct iattr lower_ia = { .ia_valid = 0 }; int rc; rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length); if (rc) return rc; rc = truncate_upper(dentry, &ia, &lower_ia); if (!rc && lower_ia.ia_valid & ATTR_SIZE) { struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); inode_lock(d_inode(lower_dentry)); rc = notify_change(lower_dentry, &lower_ia, NULL); inode_unlock(d_inode(lower_dentry)); } return rc; } static int ecryptfs_permission(struct inode *inode, int mask) { return inode_permission(ecryptfs_inode_to_lower(inode), mask); } /** * ecryptfs_setattr * @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 dentry *dentry, struct iattr *ia) { int rc = 0; struct dentry *lower_dentry; struct iattr lower_ia; struct inode *inode; struct inode *lower_inode; struct ecryptfs_crypt_stat *crypt_stat; crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat; if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) { rc = ecryptfs_init_crypt_stat(crypt_stat); if (rc) return rc; } inode = d_inode(dentry); lower_inode = ecryptfs_inode_to_lower(inode); lower_dentry = ecryptfs_dentry_to_lower(dentry); 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 = inode_change_ok(inode, ia); if (rc) goto out; if (ia->ia_valid & ATTR_SIZE) { rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size); if (rc) goto out; } 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 (ia->ia_valid & ATTR_SIZE) { rc = truncate_upper(dentry, ia, &lower_ia); if (rc < 0) goto out; } /* * mode change is for clearing setuid/setgid bits. Allow lower fs * to interpret this in its own way. */ if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) lower_ia.ia_valid &= ~ATTR_MODE; inode_lock(d_inode(lower_dentry)); rc = notify_change(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 vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { 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(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 vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct kstat lower_stat; int rc; rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat); if (!rc) { fsstack_copy_attr_all(d_inode(dentry), ecryptfs_inode_to_lower(d_inode(dentry))); generic_fillattr(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 = 0; struct dentry *lower_dentry; lower_dentry = ecryptfs_dentry_to_lower(dentry); if (!d_inode(lower_dentry)->i_op->setxattr) { rc = -EOPNOTSUPP; goto out; } rc = vfs_setxattr(lower_dentry, name, value, size, flags); if (!rc && inode) fsstack_copy_attr_all(inode, d_inode(lower_dentry)); 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 = 0; if (!lower_inode->i_op->getxattr) { rc = -EOPNOTSUPP; goto out; } inode_lock(lower_inode); rc = lower_inode->i_op->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, const char *name) { int rc = 0; struct dentry *lower_dentry; lower_dentry = ecryptfs_dentry_to_lower(dentry); if (!d_inode(lower_dentry)->i_op->removexattr) { rc = -EOPNOTSUPP; goto out; } inode_lock(d_inode(lower_dentry)); rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name); inode_unlock(d_inode(lower_dentry)); out: return rc; } const struct inode_operations ecryptfs_symlink_iops = { .readlink = generic_readlink, .get_link = ecryptfs_get_link, .permission = ecryptfs_permission, .setattr = ecryptfs_setattr, .getattr = ecryptfs_getattr_link, .setxattr = ecryptfs_setxattr, .getxattr = ecryptfs_getxattr, .listxattr = ecryptfs_listxattr, .removexattr = ecryptfs_removexattr }; 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, .setxattr = ecryptfs_setxattr, .getxattr = ecryptfs_getxattr, .listxattr = ecryptfs_listxattr, .removexattr = ecryptfs_removexattr }; const struct inode_operations ecryptfs_main_iops = { .permission = ecryptfs_permission, .setattr = ecryptfs_setattr, .getattr = ecryptfs_getattr, .setxattr = ecryptfs_setxattr, .getxattr = ecryptfs_getxattr, .listxattr = ecryptfs_listxattr, .removexattr = ecryptfs_removexattr };