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Message-Id: <1352755732-16064-1-git-send-email-herton.krzesinski@canonical.com>
Date: Mon, 12 Nov 2012 19:28:52 -0200
From: Herton Ronaldo Krzesinski <herton.krzesinski@...onical.com>
To: Tyler Hicks <tyhicks@...onical.com>
Cc: John Johansen <john.johansen@...onical.com>,
Colin Ian King <colin.king@...onical.com>,
Herton Ronaldo Krzesinski <herton.krzesinski@...onical.com>,
linux-kernel@...r.kernel.org, stable@...r.kernel.org,
kernel-team@...ts.ubuntu.com
Subject: [ 3.5.yuz extended stable] Patch "eCryptfs: Initialize empty lower files when opening them" has been added to staging queue
This is a note to let you know that I have just added a patch titled
eCryptfs: Initialize empty lower files when opening them
to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue
If you, or anyone else, feels it should not be added to the 3.5
Linux kernel, or for any feedback related to it, please reply to
this email. For more information on extended stable, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Herton
------
>From 818bcc810cf0f5319ac82eaf3b07466fa118aa45 Mon Sep 17 00:00:00 2001
From: Tyler Hicks <tyhicks@...onical.com>
Date: Wed, 20 Jun 2012 23:50:59 -0700
Subject: [PATCH] eCryptfs: Initialize empty lower files when opening them
commit e3ccaa9761200952cc269b1f4b7d7bb77a5e071b upstream.
Historically, eCryptfs has only initialized lower files in the
ecryptfs_create() path. Lower file initialization is the act of writing
the cryptographic metadata from the inode's crypt_stat to the header of
the file. The ecryptfs_open() path already expects that metadata to be
in the header of the file.
A number of users have reported empty lower files in beneath their
eCryptfs mounts. Most of the causes for those empty files being left
around have been addressed, but the presence of empty files causes
problems due to the lack of proper cryptographic metadata.
To transparently solve this problem, this patch initializes empty lower
files in the ecryptfs_open() error path. If the metadata is unreadable
due to the lower inode size being 0, plaintext passthrough support is
not in use, and the metadata is stored in the header of the file (as
opposed to the user.ecryptfs extended attribute), the lower file will be
initialized.
The number of nested conditionals in ecryptfs_open() was getting out of
hand, so a helper function was created. To avoid the same nested
conditional problem, the conditional logic was reversed inside of the
helper function.
https://launchpad.net/bugs/911507
Signed-off-by: Tyler Hicks <tyhicks@...onical.com>
Cc: John Johansen <john.johansen@...onical.com>
Cc: Colin Ian King <colin.king@...onical.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@...onical.com>
---
fs/ecryptfs/ecryptfs_kernel.h | 2 ++
fs/ecryptfs/file.c | 71 ++++++++++++++++++++++++++---------------
fs/ecryptfs/inode.c | 4 +--
3 files changed, 49 insertions(+), 28 deletions(-)
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 867b64c..56e3aa5 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -568,6 +568,8 @@ struct ecryptfs_open_req {
struct inode *ecryptfs_get_inode(struct inode *lower_inode,
struct super_block *sb);
void ecryptfs_i_size_init(const char *page_virt, struct inode *inode);
+int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
+ struct inode *ecryptfs_inode);
int ecryptfs_decode_and_decrypt_filename(char **decrypted_name,
size_t *decrypted_name_size,
struct dentry *ecryptfs_dentry,
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 49fc575..44ce5c6 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -140,6 +140,48 @@ out:
struct kmem_cache *ecryptfs_file_info_cache;
+static int read_or_initialize_metadata(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ 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;
+}
+
/**
* ecryptfs_open
* @inode: inode speciying file to open
@@ -215,32 +257,9 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
rc = 0;
goto out;
}
- mutex_lock(&crypt_stat->cs_mutex);
- if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
- || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
- rc = ecryptfs_read_metadata(ecryptfs_dentry);
- 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 "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_put;
- }
- rc = 0;
- crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
- | ECRYPTFS_ENCRYPTED);
- mutex_unlock(&crypt_stat->cs_mutex);
- goto out;
- }
- }
- mutex_unlock(&crypt_stat->cs_mutex);
+ rc = read_or_initialize_metadata(ecryptfs_dentry);
+ if (rc)
+ goto out_put;
ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
"[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
(unsigned long long)i_size_read(inode));
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index b01c7a9..68166ea 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -200,8 +200,8 @@ out:
*
* Returns zero on success
*/
-static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
- struct inode *ecryptfs_inode)
+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;
--
1.7.9.5
--
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