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-rw-r--r--fs/ecryptfs/Makefile2
-rw-r--r--fs/ecryptfs/ecryptfs_kernel.h19
-rw-r--r--fs/ecryptfs/file.c7
-rw-r--r--fs/ecryptfs/kthread.c203
-rw-r--r--fs/ecryptfs/main.c42
5 files changed, 251 insertions, 22 deletions
diff --git a/fs/ecryptfs/Makefile b/fs/ecryptfs/Makefile
index 1e34a7fd488..b4755a85996 100644
--- a/fs/ecryptfs/Makefile
+++ b/fs/ecryptfs/Makefile
@@ -4,4 +4,4 @@
obj-$(CONFIG_ECRYPT_FS) += ecryptfs.o
-ecryptfs-objs := dentry.o file.o inode.o main.o super.o mmap.o read_write.o crypto.o keystore.o messaging.o netlink.o miscdev.o debug.o
+ecryptfs-objs := dentry.o file.o inode.o main.o super.o mmap.o read_write.o crypto.o keystore.o messaging.o netlink.o miscdev.o kthread.o debug.o
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index c15c25745e0..b4a0cccfdd7 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -559,6 +559,20 @@ extern struct kmem_cache *ecryptfs_key_record_cache;
extern struct kmem_cache *ecryptfs_key_sig_cache;
extern struct kmem_cache *ecryptfs_global_auth_tok_cache;
extern struct kmem_cache *ecryptfs_key_tfm_cache;
+extern struct kmem_cache *ecryptfs_open_req_cache;
+
+struct ecryptfs_open_req {
+#define ECRYPTFS_REQ_PROCESSED 0x00000001
+#define ECRYPTFS_REQ_DROPPED 0x00000002
+#define ECRYPTFS_REQ_ZOMBIE 0x00000004
+ u32 flags;
+ struct file **lower_file;
+ struct dentry *lower_dentry;
+ struct vfsmount *lower_mnt;
+ wait_queue_head_t wait;
+ struct mutex mux;
+ struct list_head kthread_ctl_list;
+};
int ecryptfs_interpose(struct dentry *hidden_dentry,
struct dentry *this_dentry, struct super_block *sb,
@@ -690,5 +704,10 @@ void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx);
int
ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, uid_t euid,
struct user_namespace *user_ns, struct pid *pid);
+int ecryptfs_init_kthread(void);
+void ecryptfs_destroy_kthread(void);
+int ecryptfs_privileged_open(struct file **lower_file,
+ struct dentry *lower_dentry,
+ struct vfsmount *lower_mnt);
#endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 24749bf0668..f0be2905152 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -192,6 +192,13 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
| ECRYPTFS_ENCRYPTED);
}
mutex_unlock(&crypt_stat->cs_mutex);
+ if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
+ && !(file->f_flags & O_RDONLY)) {
+ rc = -EPERM;
+ printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
+ "file must hence be opened RO\n", __func__);
+ 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/kthread.c b/fs/ecryptfs/kthread.c
new file mode 100644
index 00000000000..c440c6b58b2
--- /dev/null
+++ b/fs/ecryptfs/kthread.c
@@ -0,0 +1,203 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ * Author(s): Michael A. Halcrow <mahalcro@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/kthread.h>
+#include <linux/freezer.h>
+#include <linux/wait.h>
+#include <linux/mount.h>
+#include "ecryptfs_kernel.h"
+
+struct kmem_cache *ecryptfs_open_req_cache;
+
+static struct ecryptfs_kthread_ctl {
+#define ECRYPTFS_KTHREAD_ZOMBIE 0x00000001
+ u32 flags;
+ struct mutex mux;
+ struct list_head req_list;
+ wait_queue_head_t wait;
+} ecryptfs_kthread_ctl;
+
+static struct task_struct *ecryptfs_kthread;
+
+/**
+ * ecryptfs_threadfn
+ * @ignored: ignored
+ *
+ * The eCryptfs kernel thread that has the responsibility of getting
+ * the lower persistent file with RW permissions.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_threadfn(void *ignored)
+{
+ set_freezable();
+ while (1) {
+ struct ecryptfs_open_req *req;
+
+ wait_event_freezable(
+ ecryptfs_kthread_ctl.wait,
+ (!list_empty(&ecryptfs_kthread_ctl.req_list)
+ || kthread_should_stop()));
+ mutex_lock(&ecryptfs_kthread_ctl.mux);
+ if (ecryptfs_kthread_ctl.flags & ECRYPTFS_KTHREAD_ZOMBIE) {
+ mutex_unlock(&ecryptfs_kthread_ctl.mux);
+ goto out;
+ }
+ while (!list_empty(&ecryptfs_kthread_ctl.req_list)) {
+ req = list_first_entry(&ecryptfs_kthread_ctl.req_list,
+ struct ecryptfs_open_req,
+ kthread_ctl_list);
+ mutex_lock(&req->mux);
+ list_del(&req->kthread_ctl_list);
+ if (!(req->flags & ECRYPTFS_REQ_ZOMBIE)) {
+ dget(req->lower_dentry);
+ mntget(req->lower_mnt);
+ (*req->lower_file) = dentry_open(
+ req->lower_dentry, req->lower_mnt,
+ (O_RDWR | O_LARGEFILE));
+ req->flags |= ECRYPTFS_REQ_PROCESSED;
+ }
+ wake_up(&req->wait);
+ mutex_unlock(&req->mux);
+ }
+ mutex_unlock(&ecryptfs_kthread_ctl.mux);
+ }
+out:
+ return 0;
+}
+
+int ecryptfs_init_kthread(void)
+{
+ int rc = 0;
+
+ mutex_init(&ecryptfs_kthread_ctl.mux);
+ init_waitqueue_head(&ecryptfs_kthread_ctl.wait);
+ INIT_LIST_HEAD(&ecryptfs_kthread_ctl.req_list);
+ ecryptfs_kthread = kthread_run(&ecryptfs_threadfn, NULL,
+ "ecryptfs-kthread");
+ if (IS_ERR(ecryptfs_kthread)) {
+ rc = PTR_ERR(ecryptfs_kthread);
+ printk(KERN_ERR "%s: Failed to create kernel thread; rc = [%d]"
+ "\n", __func__, rc);
+ }
+ return rc;
+}
+
+void ecryptfs_destroy_kthread(void)
+{
+ struct ecryptfs_open_req *req;
+
+ mutex_lock(&ecryptfs_kthread_ctl.mux);
+ ecryptfs_kthread_ctl.flags |= ECRYPTFS_KTHREAD_ZOMBIE;
+ list_for_each_entry(req, &ecryptfs_kthread_ctl.req_list,
+ kthread_ctl_list) {
+ mutex_lock(&req->mux);
+ req->flags |= ECRYPTFS_REQ_ZOMBIE;
+ wake_up(&req->wait);
+ mutex_unlock(&req->mux);
+ }
+ mutex_unlock(&ecryptfs_kthread_ctl.mux);
+ kthread_stop(ecryptfs_kthread);
+ wake_up(&ecryptfs_kthread_ctl.wait);
+}
+
+/**
+ * ecryptfs_privileged_open
+ * @lower_file: Result of dentry_open by root on lower dentry
+ * @lower_dentry: Lower dentry for file to open
+ * @lower_mnt: Lower vfsmount for file to open
+ *
+ * This function gets a r/w file opened againt the lower dentry.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_privileged_open(struct file **lower_file,
+ struct dentry *lower_dentry,
+ struct vfsmount *lower_mnt)
+{
+ struct ecryptfs_open_req *req;
+ int rc = 0;
+
+ /* Corresponding dput() and mntput() are done when the
+ * persistent file is fput() when the eCryptfs inode is
+ * destroyed. */
+ dget(lower_dentry);
+ mntget(lower_mnt);
+ (*lower_file) = dentry_open(lower_dentry, lower_mnt,
+ (O_RDWR | O_LARGEFILE));
+ if (!IS_ERR(*lower_file))
+ goto out;
+ req = kmem_cache_alloc(ecryptfs_open_req_cache, GFP_KERNEL);
+ if (!req) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ mutex_init(&req->mux);
+ req->lower_file = lower_file;
+ req->lower_dentry = lower_dentry;
+ req->lower_mnt = lower_mnt;
+ init_waitqueue_head(&req->wait);
+ req->flags = 0;
+ mutex_lock(&ecryptfs_kthread_ctl.mux);
+ if (ecryptfs_kthread_ctl.flags & ECRYPTFS_KTHREAD_ZOMBIE) {
+ rc = -EIO;
+ mutex_unlock(&ecryptfs_kthread_ctl.mux);
+ printk(KERN_ERR "%s: We are in the middle of shutting down; "
+ "aborting privileged request to open lower file\n",
+ __func__);
+ goto out_free;
+ }
+ list_add_tail(&req->kthread_ctl_list, &ecryptfs_kthread_ctl.req_list);
+ mutex_unlock(&ecryptfs_kthread_ctl.mux);
+ wake_up(&ecryptfs_kthread_ctl.wait);
+ wait_event(req->wait, (req->flags != 0));
+ mutex_lock(&req->mux);
+ BUG_ON(req->flags == 0);
+ if (req->flags & ECRYPTFS_REQ_DROPPED
+ || req->flags & ECRYPTFS_REQ_ZOMBIE) {
+ rc = -EIO;
+ printk(KERN_WARNING "%s: Privileged open request dropped\n",
+ __func__);
+ goto out_unlock;
+ }
+ if (IS_ERR(*req->lower_file)) {
+ rc = PTR_ERR(*req->lower_file);
+ dget(lower_dentry);
+ mntget(lower_mnt);
+ (*lower_file) = dentry_open(lower_dentry, lower_mnt,
+ (O_RDONLY | O_LARGEFILE));
+ if (IS_ERR(*lower_file)) {
+ rc = PTR_ERR(*req->lower_file);
+ (*lower_file) = NULL;
+ printk(KERN_WARNING "%s: Error attempting privileged "
+ "open of lower file with either RW or RO "
+ "perms; rc = [%d]. Giving up.\n",
+ __func__, rc);
+ }
+ }
+out_unlock:
+ mutex_unlock(&req->mux);
+out_free:
+ kmem_cache_free(ecryptfs_open_req_cache, req);
+out:
+ return rc;
+}
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index d603631601e..f36ab2feea2 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -130,26 +130,12 @@ static int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
- /* Corresponding dput() and mntput() are done when the
- * persistent file is fput() when the eCryptfs inode
- * is destroyed. */
- dget(lower_dentry);
- mntget(lower_mnt);
- inode_info->lower_file = dentry_open(lower_dentry,
- lower_mnt,
- (O_RDWR | O_LARGEFILE));
- if (IS_ERR(inode_info->lower_file)) {
- dget(lower_dentry);
- mntget(lower_mnt);
- inode_info->lower_file = dentry_open(lower_dentry,
- lower_mnt,
- (O_RDONLY
- | O_LARGEFILE));
- }
- if (IS_ERR(inode_info->lower_file)) {
+ rc = ecryptfs_privileged_open(&inode_info->lower_file,
+ lower_dentry, lower_mnt);
+ if (rc || IS_ERR(inode_info->lower_file)) {
printk(KERN_ERR "Error opening lower persistent file "
- "for lower_dentry [0x%p] and lower_mnt [0x%p]\n",
- lower_dentry, lower_mnt);
+ "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
+ "rc = [%d]\n", lower_dentry, lower_mnt, rc);
rc = PTR_ERR(inode_info->lower_file);
inode_info->lower_file = NULL;
}
@@ -679,6 +665,11 @@ static struct ecryptfs_cache_info {
.name = "ecryptfs_key_tfm_cache",
.size = sizeof(struct ecryptfs_key_tfm),
},
+ {
+ .cache = &ecryptfs_open_req_cache,
+ .name = "ecryptfs_open_req_cache",
+ .size = sizeof(struct ecryptfs_open_req),
+ },
};
static void ecryptfs_free_kmem_caches(void)
@@ -795,11 +786,17 @@ static int __init ecryptfs_init(void)
printk(KERN_ERR "sysfs registration failed\n");
goto out_unregister_filesystem;
}
+ rc = ecryptfs_init_kthread();
+ if (rc) {
+ printk(KERN_ERR "%s: kthread initialization failed; "
+ "rc = [%d]\n", __func__, rc);
+ goto out_do_sysfs_unregistration;
+ }
rc = ecryptfs_init_messaging(ecryptfs_transport);
if (rc) {
- ecryptfs_printk(KERN_ERR, "Failure occured while attempting to "
+ printk(KERN_ERR "Failure occured while attempting to "
"initialize the eCryptfs netlink socket\n");
- goto out_do_sysfs_unregistration;
+ goto out_destroy_kthread;
}
rc = ecryptfs_init_crypto();
if (rc) {
@@ -814,6 +811,8 @@ static int __init ecryptfs_init(void)
goto out;
out_release_messaging:
ecryptfs_release_messaging(ecryptfs_transport);
+out_destroy_kthread:
+ ecryptfs_destroy_kthread();
out_do_sysfs_unregistration:
do_sysfs_unregistration();
out_unregister_filesystem:
@@ -833,6 +832,7 @@ static void __exit ecryptfs_exit(void)
printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
"rc = [%d]\n", rc);
ecryptfs_release_messaging(ecryptfs_transport);
+ ecryptfs_destroy_kthread();
do_sysfs_unregistration();
unregister_filesystem(&ecryptfs_fs_type);
ecryptfs_free_kmem_caches();
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-20 20:42:06 +0000