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List: git-commits-head
Subject: eCryptfs: Fix new inode race condition
From: Linux Kernel Mailing List <linux-kernel () vger ! kernel ! org>
Date: 2011-05-29 21:59:29
Message-ID: 201105292159.p4TLxTEh019578 () hera ! kernel ! org
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Gitweb: http://git.kernel.org/linus/3b06b3ebf44170c90c893c6c80916db6e922b9f2
Commit: 3b06b3ebf44170c90c893c6c80916db6e922b9f2
Parent: 5ccf92037c7c6e6f28175fd245284923f939259f
Author: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
AuthorDate: Tue May 24 03:49:02 2011 -0500
Committer: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
CommitDate: Sun May 29 14:23:39 2011 -0500
eCryptfs: Fix new inode race condition
Only unlock and d_add() new inodes after the plaintext inode size has
been read from the lower filesystem. This fixes a race condition that
was sometimes seen during a multi-job kernel build in an eCryptfs mount.
https://bugzilla.kernel.org/show_bug.cgi?id=36002
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Reported-by: David <david@unsolicited.net>
Tested-by: David <david@unsolicited.net>
---
fs/ecryptfs/crypto.c | 4 +-
fs/ecryptfs/ecryptfs_kernel.h | 4 +-
fs/ecryptfs/file.c | 2 +-
fs/ecryptfs/inode.c | 42 +++++++++++++++++++++-------------------
fs/ecryptfs/main.c | 6 ++--
5 files changed, 30 insertions(+), 28 deletions(-)
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index b8d5c80..f48c498 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1568,11 +1568,11 @@ out:
}
int ecryptfs_read_and_validate_xattr_region(char *page_virt,
- struct dentry *ecryptfs_dentry)
+ struct inode *inode)
{
int rc;
- rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
+ rc = ecryptfs_read_xattr_region(page_virt, inode);
if (rc)
goto out;
if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 41a4532..72aa24a 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -662,7 +662,7 @@ void ecryptfs_write_crypt_stat_flags(char *page_virt,
int ecryptfs_read_and_validate_header_region(char *data,
struct inode *ecryptfs_inode);
int ecryptfs_read_and_validate_xattr_region(char *page_virt,
- struct dentry *ecryptfs_dentry);
+ struct inode *inode);
u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes);
int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code);
void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
@@ -753,7 +753,7 @@ int ecryptfs_privileged_open(struct file **lower_file,
struct dentry *lower_dentry,
struct vfsmount *lower_mnt,
const struct cred *cred);
-int ecryptfs_get_lower_file(struct dentry *ecryptfs_dentry);
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode);
void ecryptfs_put_lower_file(struct inode *inode);
int
ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 566e547..4ec9eb0 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -191,7 +191,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
| ECRYPTFS_ENCRYPTED);
}
mutex_unlock(&crypt_stat->cs_mutex);
- rc = ecryptfs_get_lower_file(ecryptfs_dentry);
+ rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index fc7d2b7..f0ad965 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -259,7 +259,8 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
"context; rc = [%d]\n", rc);
goto out;
}
- rc = ecryptfs_get_lower_file(ecryptfs_dentry);
+ rc = ecryptfs_get_lower_file(ecryptfs_dentry,
+ ecryptfs_dentry->d_inode);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
@@ -350,50 +351,51 @@ static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry,
__func__, rc);
goto out;
}
- if (inode->i_state & I_NEW)
- unlock_new_inode(inode);
- d_add(ecryptfs_dentry, inode);
- if (S_ISDIR(lower_inode->i_mode))
- goto out;
- if (S_ISLNK(lower_inode->i_mode))
- goto out;
- if (special_file(lower_inode->i_mode))
+ if (!S_ISREG(inode->i_mode)) {
+ if (inode->i_state & I_NEW)
+ unlock_new_inode(inode);
+ d_add(ecryptfs_dentry, inode);
goto out;
+ }
/* Released in this function */
page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
if (!page_virt) {
printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
__func__);
rc = -ENOMEM;
+ make_bad_inode(inode);
goto out;
}
- rc = ecryptfs_get_lower_file(ecryptfs_dentry);
+ rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
ecryptfs_dentry->d_name.name, rc);
+ make_bad_inode(inode);
goto out_free_kmem;
}
put_lower = 1;
- crypt_stat = &ecryptfs_inode_to_private(
- ecryptfs_dentry->d_inode)->crypt_stat;
+ crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
/* TODO: lock for crypt_stat comparison */
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
ecryptfs_set_default_sizes(crypt_stat);
- rc = ecryptfs_read_and_validate_header_region(page_virt,
- ecryptfs_dentry->d_inode);
+ rc = ecryptfs_read_and_validate_header_region(page_virt, inode);
if (rc) {
memset(page_virt, 0, PAGE_CACHE_SIZE);
rc = ecryptfs_read_and_validate_xattr_region(page_virt,
- ecryptfs_dentry);
+ inode);
if (rc) {
rc = 0;
- goto out_free_kmem;
+ goto unlock_inode;
}
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
- ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
+ ecryptfs_i_size_init(page_virt, inode);
+unlock_inode:
+ if (inode->i_state & I_NEW)
+ unlock_new_inode(inode);
+ d_add(ecryptfs_dentry, inode);
out_free_kmem:
kmem_cache_free(ecryptfs_header_cache_2, page_virt);
goto out;
@@ -403,7 +405,7 @@ out_put:
d_drop(ecryptfs_dentry);
out:
if (put_lower)
- ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
+ ecryptfs_put_lower_file(inode);
return rc;
}
@@ -843,7 +845,7 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia,
lower_ia->ia_valid &= ~ATTR_SIZE;
return 0;
}
- rc = ecryptfs_get_lower_file(dentry);
+ rc = ecryptfs_get_lower_file(dentry, inode);
if (rc)
return rc;
crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
@@ -999,7 +1001,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
mount_crypt_stat = &ecryptfs_superblock_to_private(
dentry->d_sb)->mount_crypt_stat;
- rc = ecryptfs_get_lower_file(dentry);
+ rc = ecryptfs_get_lower_file(dentry, inode);
if (rc) {
mutex_unlock(&crypt_stat->cs_mutex);
goto out;
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 7c697ab..943a4f5 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -135,12 +135,12 @@ static int ecryptfs_init_lower_file(struct dentry *dentry,
return rc;
}
-int ecryptfs_get_lower_file(struct dentry *dentry)
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
{
- struct ecryptfs_inode_info *inode_info =
- ecryptfs_inode_to_private(dentry->d_inode);
+ struct ecryptfs_inode_info *inode_info;
int count, rc = 0;
+ inode_info = ecryptfs_inode_to_private(inode);
mutex_lock(&inode_info->lower_file_mutex);
count = atomic_inc_return(&inode_info->lower_file_count);
if (WARN_ON_ONCE(count < 1))
--
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