From 3b06b3ebf44170c90c893c6c80916db6e922b9f2 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 24 May 2011 03:49:02 -0500 Subject: [PATCH] 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 Reported-by: David Tested-by: David --- 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 b8d5c8091024..f48c4987a15c 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1568,11 +1568,11 @@ int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) } 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 41a453236371..72aa24a4c71e 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 566e5472f78c..4ec9eb00a241 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 fc7d2b748503..f0ad965d7d51 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 @@ static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry, 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 7c697abab396..943a4f55ed6d 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)) -- GitLab