// 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 <mhalcrow@us.ibm.com> *   		Michael C. Thompson <mcthomps@us.ibm.com> */ #include <linux/file.h>#include <linux/poll.h>#include <linux/slab.h>#include <linux/mount.h>#include <linux/pagemap.h>#include <linux/security.h>#include <linux/compat.h>#include <linux/fs_stack.h>#include "ecryptfs_kernel.h" /* * ecryptfs_read_update_atime * * generic_file_read updates the atime of upper layer inode.  But, it * doesn't give us a chance to update the atime of the lower layer * inode.  This function is a wrapper to generic_file_read.  It * updates the atime of the lower level inode if generic_file_read * returns without any errors. This is to be used only for file reads. * The function to be used for directory reads is ecryptfs_read. */static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,				struct iov_iter *to){	ssize_t rc;	struct file *file = iocb->ki_filp; 	rc = generic_file_read_iter(iocb, to);	if (rc >= 0) {		struct path path = ecryptfs_lower_path(file->f_path.dentry);		touch_atime(&path);	}	return rc;} /* * ecryptfs_splice_read_update_atime * * filemap_splice_read updates the atime of upper layer inode.  But, it * doesn't give us a chance to update the atime of the lower layer inode.  This * function is a wrapper to generic_file_read.  It updates the atime of the * lower level inode if generic_file_read returns without any errors. This is * to be used only for file reads.  The function to be used for directory reads * is ecryptfs_read. */static ssize_t ecryptfs_splice_read_update_atime(struct file *in, loff_t *ppos,						 struct pipe_inode_info *pipe,						 size_t len, unsigned int flags){	ssize_t rc; 	rc = filemap_splice_read(in, ppos, pipe, len, flags);	if (rc >= 0) {		struct path path = ecryptfs_lower_path(in->f_path.dentry);		touch_atime(&path);	}	return rc;} struct ecryptfs_getdents_callback {	struct dir_context ctx;	struct dir_context *caller;	struct super_block *sb;	int filldir_called;	int entries_written;}; /* Inspired by generic filldir in fs/readdir.c */static boolecryptfs_filldir(struct dir_context *ctx, const char *lower_name,		 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type){	struct ecryptfs_getdents_callback *buf =		container_of(ctx, struct ecryptfs_getdents_callback, ctx);	size_t name_size;	char *name;	int err;	bool res; 	buf->filldir_called++;	err = ecryptfs_decode_and_decrypt_filename(&name, &name_size,						   buf->sb, lower_name,						   lower_namelen);	if (err) {		if (err != -EINVAL) {			ecryptfs_printk(KERN_DEBUG,					"%s: Error attempting to decode and decrypt filename [%s]; rc = [%d]\n",					__func__, lower_name, err);			return false;		} 		/* Mask -EINVAL errors as these are most likely due a plaintext		 * filename present in the lower filesystem despite filename		 * encryption being enabled. One unavoidable example would be		 * the "lost+found" dentry in the root directory of an Ext4		 * filesystem.		 */		return true;	} 	buf->caller->pos = buf->ctx.pos;	res = dir_emit(buf->caller, name, name_size, ino, d_type);	kfree(name);	if (res)		buf->entries_written++;	return res;} /** * ecryptfs_readdir * @file: The eCryptfs directory file * @ctx: The actor to feed the entries to */static int ecryptfs_readdir(struct file *file, struct dir_context *ctx){	int rc;	struct file *lower_file;	struct inode *inode = file_inode(file);	struct ecryptfs_getdents_callback buf = {		.ctx.actor = ecryptfs_filldir,		.caller = ctx,		.sb = inode->i_sb,	};	lower_file = ecryptfs_file_to_lower(file);	rc = iterate_dir(lower_file, &buf.ctx);	ctx->pos = buf.ctx.pos;	if (rc >= 0 && (buf.entries_written || !buf.filldir_called))		fsstack_copy_attr_atime(inode, file_inode(lower_file));	return rc;} struct kmem_cache *ecryptfs_file_info_cache; static int read_or_initialize_metadata(struct dentry *dentry){	struct inode *inode = d_inode(dentry);	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;	struct ecryptfs_crypt_stat *crypt_stat;	int rc; 	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;	mount_crypt_stat = &ecryptfs_superblock_to_private(						inode->i_sb)->mount_crypt_stat;	mutex_lock(&crypt_stat->cs_mutex); 	if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&	    crypt_stat->flags & ECRYPTFS_KEY_VALID) {		rc = 0;		goto out;	} 	rc = ecryptfs_read_metadata(dentry);	if (!rc)		goto out; 	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {		crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED				       | ECRYPTFS_ENCRYPTED);		rc = 0;		goto out;	} 	if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&	    !i_size_read(ecryptfs_inode_to_lower(inode))) {		rc = ecryptfs_initialize_file(dentry, inode);		if (!rc)			goto out;	} 	rc = -EIO;out:	mutex_unlock(&crypt_stat->cs_mutex);	return rc;} static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma){	struct file *lower_file = ecryptfs_file_to_lower(file);	/*	 * Don't allow mmap on top of file systems that don't support it	 * natively.  If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs	 * allows recursive mounting, this will need to be extended.	 */	if (!can_mmap_file(lower_file))		return -ENODEV;	return generic_file_mmap(file, vma);} /** * ecryptfs_open * @inode: inode specifying file to open * @file: Structure to return filled in * * Opens the file specified by inode. * * Returns zero on success; non-zero otherwise */static int ecryptfs_open(struct inode *inode, struct file *file){	int rc = 0;	struct ecryptfs_crypt_stat *crypt_stat = NULL;	struct dentry *ecryptfs_dentry = file->f_path.dentry;	/* Private value of ecryptfs_dentry allocated in	 * ecryptfs_lookup() */	struct ecryptfs_file_info *file_info; 	/* Released in ecryptfs_release or end of function if failure */	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);	ecryptfs_set_file_private(file, file_info);	if (!file_info) {		ecryptfs_printk(KERN_ERR,				"Error attempting to allocate memory\n");		rc = -ENOMEM;		goto out;	}	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;	mutex_lock(&crypt_stat->cs_mutex);	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {		ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");		/* Policy code enabled in future release */		crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED				      | ECRYPTFS_ENCRYPTED);	}	mutex_unlock(&crypt_stat->cs_mutex);	rc = ecryptfs_get_lower_file(ecryptfs_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__,			ecryptfs_dentry, rc);		goto out_free;	}	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)	    == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {		rc = -EPERM;		printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "		       "file must hence be opened RO\n", __func__);		goto out_put;	}	ecryptfs_set_file_lower(		file, ecryptfs_inode_to_private(inode)->lower_file);	rc = read_or_initialize_metadata(ecryptfs_dentry);	if (rc)		goto out_put;	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "			"[0x%.16llx] size: [0x%.16llx]\n", inode, inode->i_ino,			(unsigned long long)i_size_read(inode));	goto out;out_put:	ecryptfs_put_lower_file(inode);out_free:	kmem_cache_free(ecryptfs_file_info_cache,			ecryptfs_file_to_private(file));out:	return rc;} /** * ecryptfs_dir_open * @inode: inode specifying file to open * @file: Structure to return filled in * * Opens the file specified by inode. * * Returns zero on success; non-zero otherwise */static int ecryptfs_dir_open(struct inode *inode, struct file *file){	struct dentry *ecryptfs_dentry = file->f_path.dentry;	/* Private value of ecryptfs_dentry allocated in	 * ecryptfs_lookup() */	struct ecryptfs_file_info *file_info;	struct file *lower_file;	struct path path; 	/* Released in ecryptfs_release or end of function if failure */	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);	ecryptfs_set_file_private(file, file_info);	if (unlikely(!file_info)) {		ecryptfs_printk(KERN_ERR,				"Error attempting to allocate memory\n");		return -ENOMEM;	}	path = ecryptfs_lower_path(ecryptfs_dentry);	lower_file = dentry_open(&path, file->f_flags, current_cred());	if (IS_ERR(lower_file)) {		printk(KERN_ERR "%s: Error attempting to initialize "			"the lower file for the dentry with name "			"[%pd]; rc = [%ld]\n", __func__,			ecryptfs_dentry, PTR_ERR(lower_file));		kmem_cache_free(ecryptfs_file_info_cache, file_info);		return PTR_ERR(lower_file);	}	ecryptfs_set_file_lower(file, lower_file);	return 0;} static int ecryptfs_flush(struct file *file, fl_owner_t td){	struct file *lower_file = ecryptfs_file_to_lower(file); 	if (lower_file->f_op->flush) {		filemap_write_and_wait(file->f_mapping);		return lower_file->f_op->flush(lower_file, td);	} 	return 0;} static int ecryptfs_release(struct inode *inode, struct file *file){	ecryptfs_put_lower_file(inode);	kmem_cache_free(ecryptfs_file_info_cache,			ecryptfs_file_to_private(file));	return 0;} static int ecryptfs_dir_release(struct inode *inode, struct file *file){	fput(ecryptfs_file_to_lower(file));	kmem_cache_free(ecryptfs_file_info_cache,			ecryptfs_file_to_private(file));	return 0;} static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence){	return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);} static intecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync){	int rc; 	rc = file_write_and_wait(file);	if (rc)		return rc; 	return vfs_fsync(ecryptfs_file_to_lower(file), datasync);} static int ecryptfs_fasync(int fd, struct file *file, int flag){	int rc = 0;	struct file *lower_file = NULL; 	lower_file = ecryptfs_file_to_lower(file);	if (lower_file->f_op->fasync)		rc = lower_file->f_op->fasync(fd, lower_file, flag);	return rc;} static longecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg){	struct file *lower_file = ecryptfs_file_to_lower(file);	long rc = -ENOTTY; 	if (!lower_file->f_op->unlocked_ioctl)		return rc; 	switch (cmd) {	case FITRIM:	case FS_IOC_GETFLAGS:	case FS_IOC_SETFLAGS:	case FS_IOC_GETVERSION:	case FS_IOC_SETVERSION:		rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file)); 		return rc;	default:		return rc;	}} #ifdef CONFIG_COMPATstatic longecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg){	struct file *lower_file = ecryptfs_file_to_lower(file);	long rc = -ENOIOCTLCMD; 	if (!lower_file->f_op->compat_ioctl)		return rc; 	switch (cmd) {	case FITRIM:	case FS_IOC32_GETFLAGS:	case FS_IOC32_SETFLAGS:	case FS_IOC32_GETVERSION:	case FS_IOC32_SETVERSION:		rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file)); 		return rc;	default:		return rc;	}}#endif const struct file_operations ecryptfs_dir_fops = {	.iterate_shared = ecryptfs_readdir,	.read = generic_read_dir,	.unlocked_ioctl = ecryptfs_unlocked_ioctl,#ifdef CONFIG_COMPAT	.compat_ioctl = ecryptfs_compat_ioctl,#endif	.open = ecryptfs_dir_open,	.release = ecryptfs_dir_release,	.fsync = ecryptfs_fsync,	.llseek = ecryptfs_dir_llseek,}; const struct file_operations ecryptfs_main_fops = {	.llseek = generic_file_llseek,	.read_iter = ecryptfs_read_update_atime,	.write_iter = generic_file_write_iter,	.unlocked_ioctl = ecryptfs_unlocked_ioctl,#ifdef CONFIG_COMPAT	.compat_ioctl = ecryptfs_compat_ioctl,#endif	.mmap = ecryptfs_mmap,	.open = ecryptfs_open,	.flush = ecryptfs_flush,	.release = ecryptfs_release,	.fsync = ecryptfs_fsync,	.fasync = ecryptfs_fasync,	.splice_read = ecryptfs_splice_read_update_atime,};