1 files changed, 440 insertions, 0 deletions

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
new file mode 100644
index 000000000000..c8550c9f9cd2
--- /dev/null
+++ b/fs/ecryptfs/file.c
@@ -0,0 +1,440 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *              Michael C. Thompson <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/poll.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/security.h>
+#include <linux/smp_lock.h>
+#include <linux/compat.h>
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_llseek
+ * @file: File we are seeking in
+ * @offset: The offset to seek to
+ * @origin: 2 - offset from i_size; 1 - offset from f_pos
+ *
+ * Returns the position we have seeked to, or negative on error
+ */
+static loff_t ecryptfs_llseek(struct file *file, loff_t offset, int origin)
+{
+        loff_t rv;
+        loff_t new_end_pos;
+        int rc;
+        int expanding_file = 0;
+        struct inode *inode = file->f_mapping->host;
+
+        /* If our offset is past the end of our file, we're going to
+         * need to grow it so we have a valid length of 0's */
+        new_end_pos = offset;
+        switch (origin) {
+        case 2:
+                new_end_pos += i_size_read(inode);
+                expanding_file = 1;
+                break;
+        case 1:
+                new_end_pos += file->f_pos;
+                if (new_end_pos > i_size_read(inode)) {
+                        ecryptfs_printk(KERN_DEBUG, "new_end_pos(=[0x%.16x]) "
+                                        "> i_size_read(inode)(=[0x%.16x])\n",
+                                        new_end_pos, i_size_read(inode));
+                        expanding_file = 1;
+                }
+                break;
+        default:
+                if (new_end_pos > i_size_read(inode)) {
+                        ecryptfs_printk(KERN_DEBUG, "new_end_pos(=[0x%.16x]) "
+                                        "> i_size_read(inode)(=[0x%.16x])\n",
+                                        new_end_pos, i_size_read(inode));
+                        expanding_file = 1;
+                }
+        }
+        ecryptfs_printk(KERN_DEBUG, "new_end_pos = [0x%.16x]\n", new_end_pos);
+        if (expanding_file) {
+                rc = ecryptfs_truncate(file->f_dentry, new_end_pos);
+                if (rc) {
+                        rv = rc;
+                        ecryptfs_printk(KERN_ERR, "Error on attempt to "
+                                        "truncate to (higher) offset [0x%.16x];"
+                                        " rc = [%d]\n", new_end_pos, rc);
+                        goto out;
+                }
+        }
+        rv = generic_file_llseek(file, offset, origin);
+out:
+        return rv;
+}
+
+/**
+ * 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,
+                                const struct iovec *iov,
+                                unsigned long nr_segs, loff_t pos)
+{
+        int rc;
+        struct dentry *lower_dentry;
+        struct vfsmount *lower_vfsmount;
+        struct file *file = iocb->ki_filp;
+
+        rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
+        /*
+         * Even though this is a async interface, we need to wait
+         * for IO to finish to update atime
+         */
+        if (-EIOCBQUEUED == rc)
+                rc = wait_on_sync_kiocb(iocb);
+        if (rc >= 0) {
+                lower_dentry = ecryptfs_dentry_to_lower(file->f_dentry);
+                lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_dentry);
+                touch_atime(lower_vfsmount, lower_dentry);
+        }
+        return rc;
+}
+
+struct ecryptfs_getdents_callback {
+        void *dirent;
+        struct dentry *dentry;
+        filldir_t filldir;
+        int err;
+        int filldir_called;
+        int entries_written;
+};
+
+/* Inspired by generic filldir in fs/readir.c */
+static int
+ecryptfs_filldir(void *dirent, const char *name, int namelen, loff_t offset,
+                 u64 ino, unsigned int d_type)
+{
+        struct ecryptfs_crypt_stat *crypt_stat;
+        struct ecryptfs_getdents_callback *buf =
+            (struct ecryptfs_getdents_callback *)dirent;
+        int rc;
+        int decoded_length;
+        char *decoded_name;
+
+        crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat;
+        buf->filldir_called++;
+        decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen,
+                                                  &decoded_name);
+        if (decoded_length < 0) {
+                rc = decoded_length;
+                goto out;
+        }
+        rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset,
+                          ino, d_type);
+        kfree(decoded_name);
+        if (rc >= 0)
+                buf->entries_written++;
+out:
+        return rc;
+}
+
+/**
+ * ecryptfs_readdir
+ * @file: The ecryptfs file struct
+ * @dirent: Directory entry
+ * @filldir: The filldir callback function
+ */
+static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+        int rc;
+        struct file *lower_file;
+        struct inode *inode;
+        struct ecryptfs_getdents_callback buf;
+
+        lower_file = ecryptfs_file_to_lower(file);
+        lower_file->f_pos = file->f_pos;
+        inode = file->f_dentry->d_inode;
+        memset(&buf, 0, sizeof(buf));
+        buf.dirent = dirent;
+        buf.dentry = file->f_dentry;
+        buf.filldir = filldir;
+retry:
+        buf.filldir_called = 0;
+        buf.entries_written = 0;
+        buf.err = 0;
+        rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
+        if (buf.err)
+                rc = buf.err;
+        if (buf.filldir_called && !buf.entries_written)
+                goto retry;
+        file->f_pos = lower_file->f_pos;
+        if (rc >= 0)
+                ecryptfs_copy_attr_atime(inode, lower_file->f_dentry->d_inode);
+        return rc;
+}
+
+struct kmem_cache *ecryptfs_file_info_cache;
+
+/**
+ * ecryptfs_open
+ * @inode: inode speciying 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 ecryptfs_mount_crypt_stat *mount_crypt_stat;
+        struct dentry *ecryptfs_dentry = file->f_dentry;
+        /* Private value of ecryptfs_dentry allocated in
+         * ecryptfs_lookup() */
+        struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+        struct inode *lower_inode = NULL;
+        struct file *lower_file = NULL;
+        struct vfsmount *lower_mnt;
+        struct ecryptfs_file_info *file_info;
+        int lower_flags;
+
+        /* Released in ecryptfs_release or end of function if failure */
+        file_info = kmem_cache_alloc(ecryptfs_file_info_cache, SLAB_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;
+        }
+        memset(file_info, 0, sizeof(*file_info));
+        lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+        crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+        mount_crypt_stat = &ecryptfs_superblock_to_private(
+                ecryptfs_dentry->d_sb)->mount_crypt_stat;
+        mutex_lock(&crypt_stat->cs_mutex);
+        if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED)) {
+                ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
+                /* Policy code enabled in future release */
+                ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED);
+                ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
+        }
+        mutex_unlock(&crypt_stat->cs_mutex);
+        /* This mntget & dget is undone via fput when the file is released */
+        dget(lower_dentry);
+        lower_flags = file->f_flags;
+        if ((lower_flags & O_ACCMODE) == O_WRONLY)
+                lower_flags = (lower_flags & O_ACCMODE) | O_RDWR;
+        if (file->f_flags & O_APPEND)
+                lower_flags &= ~O_APPEND;
+        lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
+        mntget(lower_mnt);
+        /* Corresponding fput() in ecryptfs_release() */
+        lower_file = dentry_open(lower_dentry, lower_mnt, lower_flags);
+        if (IS_ERR(lower_file)) {
+                rc = PTR_ERR(lower_file);
+                ecryptfs_printk(KERN_ERR, "Error opening lower file\n");
+                goto out_puts;
+        }
+        ecryptfs_set_file_lower(file, lower_file);
+        /* Isn't this check the same as the one in lookup? */
+        lower_inode = lower_dentry->d_inode;
+        if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
+                ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
+                ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
+                rc = 0;
+                goto out;
+        }
+        mutex_lock(&crypt_stat->cs_mutex);
+        if (i_size_read(lower_inode) < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
+                if (!(mount_crypt_stat->flags
+                      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
+                        rc = -EIO;
+                        printk(KERN_WARNING "Attempt to read file that is "
+                               "not in a valid eCryptfs format, and plaintext "
+                               "passthrough mode is not enabled; returning "
+                               "-EIO\n");
+                        mutex_unlock(&crypt_stat->cs_mutex);
+                        goto out_puts;
+                }
+                crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+                rc = 0;
+                mutex_unlock(&crypt_stat->cs_mutex);
+                goto out;
+        } else if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
+                                        ECRYPTFS_POLICY_APPLIED)
+                   || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
+                                           ECRYPTFS_KEY_VALID)) {
+                rc = ecryptfs_read_headers(ecryptfs_dentry, lower_file);
+                if (rc) {
+                        ecryptfs_printk(KERN_DEBUG,
+                                        "Valid headers not found\n");
+                        if (!(mount_crypt_stat->flags
+                              & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
+                                rc = -EIO;
+                                printk(KERN_WARNING "Attempt to read file that "
+                                       "is not in a valid eCryptfs format, "
+                                       "and plaintext passthrough mode is not "
+                                       "enabled; returning -EIO\n");
+                                mutex_unlock(&crypt_stat->cs_mutex);
+                                goto out_puts;
+                        }
+                        ECRYPTFS_CLEAR_FLAG(crypt_stat->flags,
+                                            ECRYPTFS_ENCRYPTED);
+                        rc = 0;
+                        mutex_unlock(&crypt_stat->cs_mutex);
+                        goto out;
+                }
+        }
+        mutex_unlock(&crypt_stat->cs_mutex);
+        ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
+                        "size: [0x%.16x]\n", inode, inode->i_ino,
+                        i_size_read(inode));
+        ecryptfs_set_file_lower(file, lower_file);
+        goto out;
+out_puts:
+        mntput(lower_mnt);
+        dput(lower_dentry);
+        kmem_cache_free(ecryptfs_file_info_cache,
+                        ecryptfs_file_to_private(file));
+out:
+        return rc;
+}
+
+static int ecryptfs_flush(struct file *file, fl_owner_t td)
+{
+        int rc = 0;
+        struct file *lower_file = NULL;
+
+        lower_file = ecryptfs_file_to_lower(file);
+        if (lower_file->f_op && lower_file->f_op->flush)
+                rc = lower_file->f_op->flush(lower_file, td);
+        return rc;
+}
+
+static int ecryptfs_release(struct inode *inode, struct file *file)
+{
+        struct file *lower_file = ecryptfs_file_to_lower(file);
+        struct ecryptfs_file_info *file_info = ecryptfs_file_to_private(file);
+        struct inode *lower_inode = ecryptfs_inode_to_lower(inode);
+
+        fput(lower_file);
+        inode->i_blocks = lower_inode->i_blocks;
+        kmem_cache_free(ecryptfs_file_info_cache, file_info);
+        return 0;
+}
+
+static int
+ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
+{
+        struct file *lower_file = ecryptfs_file_to_lower(file);
+        struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+        struct inode *lower_inode = lower_dentry->d_inode;
+        int rc = -EINVAL;
+
+        if (lower_inode->i_fop->fsync) {
+                mutex_lock(&lower_inode->i_mutex);
+                rc = lower_inode->i_fop->fsync(lower_file, lower_dentry,
+                                               datasync);
+                mutex_unlock(&lower_inode->i_mutex);
+        }
+        return rc;
+}
+
+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 && lower_file->f_op->fasync)
+                rc = lower_file->f_op->fasync(fd, lower_file, flag);
+        return rc;
+}
+
+static ssize_t ecryptfs_sendfile(struct file *file, loff_t * ppos,
+                                 size_t count, read_actor_t actor, void *target)
+{
+        struct file *lower_file = NULL;
+        int rc = -EINVAL;
+
+        lower_file = ecryptfs_file_to_lower(file);
+        if (lower_file->f_op && lower_file->f_op->sendfile)
+                rc = lower_file->f_op->sendfile(lower_file, ppos, count,
+                                                actor, target);
+
+        return rc;
+}
+
+static int ecryptfs_ioctl(struct inode *inode, struct file *file,
+                          unsigned int cmd, unsigned long arg);
+
+const struct file_operations ecryptfs_dir_fops = {
+        .readdir = ecryptfs_readdir,
+        .ioctl = ecryptfs_ioctl,
+        .mmap = generic_file_mmap,
+        .open = ecryptfs_open,
+        .flush = ecryptfs_flush,
+        .release = ecryptfs_release,
+        .fsync = ecryptfs_fsync,
+        .fasync = ecryptfs_fasync,
+        .sendfile = ecryptfs_sendfile,
+};
+
+const struct file_operations ecryptfs_main_fops = {
+        .llseek = ecryptfs_llseek,
+        .read = do_sync_read,
+        .aio_read = ecryptfs_read_update_atime,
+        .write = do_sync_write,
+        .aio_write = generic_file_aio_write,
+        .readdir = ecryptfs_readdir,
+        .ioctl = ecryptfs_ioctl,
+        .mmap = generic_file_mmap,
+        .open = ecryptfs_open,
+        .flush = ecryptfs_flush,
+        .release = ecryptfs_release,
+        .fsync = ecryptfs_fsync,
+        .fasync = ecryptfs_fasync,
+        .sendfile = ecryptfs_sendfile,
+};
+
+static int
+ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+               unsigned long arg)
+{
+        int rc = 0;
+        struct file *lower_file = NULL;
+
+        if (ecryptfs_file_to_private(file))
+                lower_file = ecryptfs_file_to_lower(file);
+        if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
+                rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
+                                             lower_file, cmd, arg);
+        else
+                rc = -ENOTTY;
+        return rc;
+}