eCryptfs: do not try to open device files on mknod
When creating device nodes, eCryptfs needs to delay actually opening the lower
persistent file until an application tries to open. Device handles may not be
backed by anything when they first come into existence.
[Valdis.Kletnieks@vt.edu: build fix]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: <Valdis.Kletnieks@vt.edu}
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index b4a0ccc..b0727f9 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -235,6 +235,7 @@
#define ECRYPTFS_METADATA_IN_XATTR 0x00000100
#define ECRYPTFS_VIEW_AS_ENCRYPTED 0x00000200
#define ECRYPTFS_KEY_SET 0x00000400
+#define ECRYPTFS_DELAY_PERSISTENT 0x00000800
u32 flags;
unsigned int file_version;
size_t iv_bytes;
@@ -574,9 +575,11 @@
struct list_head kthread_ctl_list;
};
+#define ECRYPTFS_INTERPOSE_FLAG_D_ADD 0x00000001
+#define ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE 0x00000002
int ecryptfs_interpose(struct dentry *hidden_dentry,
struct dentry *this_dentry, struct super_block *sb,
- int flag);
+ u32 flags);
int ecryptfs_fill_zeros(struct file *file, loff_t new_length);
int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
const char *name, int length,
@@ -709,5 +712,6 @@
int ecryptfs_privileged_open(struct file **lower_file,
struct dentry *lower_dentry,
struct vfsmount *lower_mnt);
+int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry);
#endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index f0be290..2c2d60d 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -199,6 +199,20 @@
"file must hence be opened RO\n", __func__);
goto out;
}
+ if (!ecryptfs_inode_to_private(inode)->lower_file) {
+ BUG_ON(!(crypt_stat->flags & ECRYPTFS_DELAY_PERSISTENT));
+ mutex_lock(&crypt_stat->cs_mutex);
+ crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+ mutex_unlock(&crypt_stat->cs_mutex);
+ rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to initialize "
+ "the persistent file for the dentry with name "
+ "[%s]; rc = [%d]\n", __func__,
+ ecryptfs_dentry->d_name.name, rc);
+ goto out;
+ }
+ }
ecryptfs_set_file_lower(
file, ecryptfs_inode_to_private(inode)->lower_file);
if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 7315547..2609087 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -308,7 +308,8 @@
d_add(dentry, NULL);
goto out;
}
- rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
+ rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb,
+ ECRYPTFS_INTERPOSE_FLAG_D_ADD);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error interposing\n");
goto out_dput;
@@ -537,7 +538,8 @@
rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
if (rc || !lower_dentry->d_inode)
goto out;
- rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+ rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb,
+ ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE);
if (rc)
goto out;
fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 10475d9..ee4f84b 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -117,7 +117,7 @@
*
* Returns zero on success; non-zero otherwise
*/
-static int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
+int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
{
struct ecryptfs_inode_info *inode_info =
ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
@@ -149,14 +149,14 @@
* @lower_dentry: Existing dentry in the lower filesystem
* @dentry: ecryptfs' dentry
* @sb: ecryptfs's super_block
- * @flag: If set to true, then d_add is called, else d_instantiate is called
+ * @flags: flags to govern behavior of interpose procedure
*
* Interposes upper and lower dentries.
*
* Returns zero on success; non-zero otherwise
*/
int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
- struct super_block *sb, int flag)
+ struct super_block *sb, u32 flags)
{
struct inode *lower_inode;
struct inode *inode;
@@ -193,7 +193,7 @@
init_special_inode(inode, lower_inode->i_mode,
lower_inode->i_rdev);
dentry->d_op = &ecryptfs_dops;
- if (flag)
+ if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
d_add(dentry, inode);
else
d_instantiate(dentry, inode);
@@ -201,12 +201,21 @@
/* This size will be overwritten for real files w/ headers and
* other metadata */
fsstack_copy_inode_size(inode, lower_inode);
- rc = ecryptfs_init_persistent_file(dentry);
- if (rc) {
- printk(KERN_ERR "%s: Error attempting to initialize the "
- "persistent file for the dentry with name [%s]; "
- "rc = [%d]\n", __func__, dentry->d_name.name, rc);
- goto out;
+ if (!(flags & ECRYPTFS_INTERPOSE_FLAG_DELAY_PERSISTENT_FILE)) {
+ rc = ecryptfs_init_persistent_file(dentry);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to initialize "
+ "the persistent file for the dentry with name "
+ "[%s]; rc = [%d]\n", __func__,
+ dentry->d_name.name, rc);
+ goto out;
+ }
+ } else {
+ struct ecryptfs_inode_info *inode_info =
+ ecryptfs_inode_to_private(dentry->d_inode);
+
+ inode_info->lower_file = NULL;
+ inode_info->crypt_stat.flags |= ECRYPTFS_DELAY_PERSISTENT;
}
out:
return rc;