From 778aeb42a708d2a57e491d2cbb5a1e74f61270b9 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 24 May 2011 04:56:23 -0500 Subject: [PATCH] eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose() ecryptfs_lookup_interpose() has turned into spaghetti code over the years. This is an effort to clean it up. - Shorten overly descriptive variable names such as ecryptfs_dentry - Simplify gotos and error paths - Create helper function for reading plaintext i_size from metadata It also includes an optimization when reading i_size from the metadata. A complete page-sized kmem_cache_alloc() was being done to read in 16 bytes of metadata. The buffer for that is now statically declared. Signed-off-by: Tyler Hicks --- fs/ecryptfs/crypto.c | 45 +++++------ fs/ecryptfs/ecryptfs_kernel.h | 7 +- fs/ecryptfs/inode.c | 141 +++++++++++++++------------------- 3 files changed, 88 insertions(+), 105 deletions(-) diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index 162f9baf9eb5..66d8e6748a46 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1201,24 +1201,19 @@ int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) return rc; } -int ecryptfs_read_and_validate_header_region(char *data, - struct inode *ecryptfs_inode) +int ecryptfs_read_and_validate_header_region(struct inode *inode) { - struct ecryptfs_crypt_stat *crypt_stat = - &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); + u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; + u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; int rc; - if (crypt_stat->extent_size == 0) - crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; - rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size, - ecryptfs_inode); - if (rc < 0) { - printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n", - __func__, rc); - goto out; - } - rc = ecryptfs_validate_marker(data + ECRYPTFS_FILE_SIZE_BYTES); -out: + rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, + inode); + if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) + return rc >= 0 ? -EINVAL : rc; + rc = ecryptfs_validate_marker(marker); + if (!rc) + ecryptfs_i_size_init(file_size, inode); return rc; } @@ -1562,19 +1557,21 @@ out: return rc; } -int ecryptfs_read_and_validate_xattr_region(char *page_virt, +int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, struct inode *inode) { + u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; + u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; int rc; - rc = ecryptfs_read_xattr_region(page_virt, inode); - if (rc) - goto out; - rc = ecryptfs_validate_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES); - if (rc) - printk(KERN_WARNING "Valid data found in [%s] xattr, but " - "the marker is invalid\n", ECRYPTFS_XATTR_NAME); -out: + rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), + ECRYPTFS_XATTR_NAME, file_size, + ECRYPTFS_SIZE_AND_MARKER_BYTES); + if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) + return rc >= 0 ? -EINVAL : rc; + rc = ecryptfs_validate_marker(marker); + if (!rc) + ecryptfs_i_size_init(file_size, inode); return rc; } diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index 72aa24a4c71e..8297ddaca7c4 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -200,6 +200,8 @@ ecryptfs_get_key_payload_data(struct key *key) #define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5 #define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8 /* 4*2 */ #define ECRYPTFS_FILE_SIZE_BYTES (sizeof(u64)) +#define ECRYPTFS_SIZE_AND_MARKER_BYTES (ECRYPTFS_FILE_SIZE_BYTES \ + + MAGIC_ECRYPTFS_MARKER_SIZE_BYTES) #define ECRYPTFS_DEFAULT_CIPHER "aes" #define ECRYPTFS_DEFAULT_KEY_BYTES 16 #define ECRYPTFS_DEFAULT_HASH "md5" @@ -659,9 +661,8 @@ int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry); void ecryptfs_write_crypt_stat_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat, size_t *written); -int ecryptfs_read_and_validate_header_region(char *data, - struct inode *ecryptfs_inode); -int ecryptfs_read_and_validate_xattr_region(char *page_virt, +int ecryptfs_read_and_validate_header_region(struct inode *inode); +int ecryptfs_read_and_validate_xattr_region(struct dentry *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); diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index f0ad965d7d51..7349ade17de6 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -307,105 +307,90 @@ out: return rc; } +static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode) +{ + struct ecryptfs_crypt_stat *crypt_stat; + int rc; + + rc = ecryptfs_get_lower_file(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__, + dentry->d_name.name, rc); + return rc; + } + + 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(inode); + ecryptfs_put_lower_file(inode); + if (rc) { + rc = ecryptfs_read_and_validate_xattr_region(dentry, inode); + if (!rc) + crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; + } + + /* Must return 0 to allow non-eCryptfs files to be looked up, too */ + return 0; +} + /** * ecryptfs_lookup_interpose - Dentry interposition for a lookup */ -static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry, +static int ecryptfs_lookup_interpose(struct dentry *dentry, struct dentry *lower_dentry, - struct inode *ecryptfs_dir_inode) + struct inode *dir_inode) { - struct dentry *lower_dir_dentry; + struct inode *inode, *lower_inode = lower_dentry->d_inode; + struct ecryptfs_dentry_info *dentry_info; struct vfsmount *lower_mnt; - struct inode *inode, *lower_inode; - struct ecryptfs_crypt_stat *crypt_stat; - char *page_virt = NULL; - int put_lower = 0, rc = 0; - - lower_dir_dentry = lower_dentry->d_parent; - lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt( - ecryptfs_dentry->d_parent)); - lower_inode = lower_dentry->d_inode; - fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode); + int rc = 0; + + lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); + fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode); BUG_ON(!lower_dentry->d_count); - ecryptfs_set_dentry_private(ecryptfs_dentry, - kmem_cache_alloc(ecryptfs_dentry_info_cache, - GFP_KERNEL)); - if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) { - rc = -ENOMEM; + + dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL); + ecryptfs_set_dentry_private(dentry, dentry_info); + if (!dentry_info) { printk(KERN_ERR "%s: Out of memory whilst attempting " "to allocate ecryptfs_dentry_info struct\n", __func__); - goto out_put; + dput(lower_dentry); + mntput(lower_mnt); + d_drop(dentry); + return -ENOMEM; } - ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry); - ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt); + ecryptfs_set_dentry_lower(dentry, lower_dentry); + ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt); + if (!lower_dentry->d_inode) { /* We want to add because we couldn't find in lower */ - d_add(ecryptfs_dentry, NULL); - goto out; + d_add(dentry, NULL); + return 0; } - inode = __ecryptfs_get_inode(lower_inode, ecryptfs_dir_inode->i_sb); + inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb); if (IS_ERR(inode)) { - rc = PTR_ERR(inode); - printk(KERN_ERR "%s: Error interposing; rc = [%d]\n", - __func__, rc); - goto out; - } - 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, 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; + printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n", + __func__, PTR_ERR(inode)); + return PTR_ERR(inode); } - put_lower = 1; - 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, inode); - if (rc) { - memset(page_virt, 0, PAGE_CACHE_SIZE); - rc = ecryptfs_read_and_validate_xattr_region(page_virt, - inode); + if (S_ISREG(inode->i_mode)) { + rc = ecryptfs_i_size_read(dentry, inode); if (rc) { - rc = 0; - goto unlock_inode; + make_bad_inode(inode); + return rc; } - crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; } - 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; -out_put: - dput(lower_dentry); - mntput(lower_mnt); - d_drop(ecryptfs_dentry); -out: - if (put_lower) - ecryptfs_put_lower_file(inode); + d_add(dentry, inode); + return rc; } -- 2.34.1