| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20211013125652.3578336-1-s.hauer@pengutronix.de>
Date: Wed, 13 Oct 2021 14:56:52 +0200
From: Sascha Hauer <s.hauer@...gutronix.de>
To: ecryptfs@...r.kernel.org
Cc: Tyler Hicks <code@...icks.com>, linux-kernel@...r.kernel.org,
kernel@...gutronix.de, Sascha Hauer <s.hauer@...gutronix.de>
Subject: [PATCH v2] eCryptfs: fix setattr on empty lower file
Depending on the synchronization state of the lower filesystem during a
power cut it can happen that a lower file is empty after that power cut.
An inode_operations::setattr operation fails with -EIO on such files,
because ecryptfs_read_metadata() fails. In e3ccaa976120 ("eCryptfs:
Initialize empty lower files when opening them") a similar problem was
solved in the open() path:
| 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.
Do the same in inode_operations::setattr to allow setattr on empty lower
files.
Signed-off-by: Sascha Hauer <s.hauer@...gutronix.de>
---
Changes since v1 (https://www.spinics.net/lists/ecryptfs/msg01397.html):
- In ecryptfs_setattr() ecryptfs_read_or_initialize_metadata() can't be
called directly as &crypt_stat->cs_mutex would be locked, but in
ecryptfs_settattr() that mutex is already locked. Create a
locked/unlocked version of ecryptfs_read_or_initialize_metadata() and
use the latter one in ecryptfs_setattr().
fs/ecryptfs/crypto.c | 61 +++++++++++++++++++++++++++++++++--
fs/ecryptfs/ecryptfs_kernel.h | 3 +-
fs/ecryptfs/file.c | 44 +------------------------
fs/ecryptfs/inode.c | 2 +-
4 files changed, 63 insertions(+), 47 deletions(-)
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index e3f5d7f3c8a0a..a14d3ef40259f 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1377,7 +1377,7 @@ int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
*
* Returns zero if valid headers found and parsed; non-zero otherwise
*/
-int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
+static int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
{
int rc;
char *page_virt;
@@ -1443,7 +1443,64 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
return rc;
}
-/*
+int ecryptfs_read_or_initialize_metadata_locked(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;
+
+ 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:
+ return rc;
+}
+
+int ecryptfs_read_or_initialize_metadata(struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct ecryptfs_crypt_stat *crypt_stat;
+ int rc;
+
+ crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+
+ mutex_lock(&crypt_stat->cs_mutex);
+
+ rc = ecryptfs_read_or_initialize_metadata_locked(dentry);
+
+ mutex_unlock(&crypt_stat->cs_mutex);
+
+ return rc;
+}
+
+/**
* ecryptfs_encrypt_filename - encrypt filename
*
* CBC-encrypts the filename. We do not want to encrypt the same
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 5f2b49e13731a..af71d6f7da91d 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -573,7 +573,8 @@ int ecryptfs_encrypt_page(struct page *page);
int ecryptfs_decrypt_page(struct page *page);
int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
struct inode *ecryptfs_inode);
-int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);
+int ecryptfs_read_or_initialize_metadata(struct dentry *dentry);
+int ecryptfs_read_or_initialize_metadata_locked(struct dentry *dentry);
int ecryptfs_new_file_context(struct inode *ecryptfs_inode);
void ecryptfs_write_crypt_stat_flags(char *page_virt,
struct ecryptfs_crypt_stat *crypt_stat,
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 18d5b91cb573e..4721aba376784 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -124,48 +124,6 @@ static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
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);
@@ -232,7 +190,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
}
ecryptfs_set_file_lower(
file, ecryptfs_inode_to_private(inode)->lower_file);
- rc = read_or_initialize_metadata(ecryptfs_dentry);
+ rc = ecryptfs_read_or_initialize_metadata(ecryptfs_dentry);
if (rc)
goto out_put;
ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 16d50dface59a..bdeeb89d1dc95 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -916,7 +916,7 @@ static int ecryptfs_setattr(struct user_namespace *mnt_userns,
mutex_unlock(&crypt_stat->cs_mutex);
goto out;
}
- rc = ecryptfs_read_metadata(dentry);
+ rc = ecryptfs_read_or_initialize_metadata_locked(dentry);
ecryptfs_put_lower_file(inode);
if (rc) {
if (!(mount_crypt_stat->flags
--
2.30.2
Powered by blists - more mailing lists