From 332ab16f830f59e7621ae8eb2c353dc135a316f6 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Thu, 14 Apr 2011 15:35:11 -0500 Subject: eCryptfs: Add reference counting to lower files For any given lower inode, eCryptfs keeps only one lower file open and multiplexes all eCryptfs file operations through that lower file. The lower file was considered "persistent" and stayed open from the first lookup through the lifetime of the inode. This patch keeps the notion of a single, per-inode lower file, but adds reference counting around the lower file so that it is closed when not currently in use. If the reference count is at 0 when an operation (such as open, create, etc.) needs to use the lower file, a new lower file is opened. Since the file is no longer persistent, all references to the term persistent file are changed to lower file. Locking is added around the sections of code that opens the lower file and assign the pointer in the inode info, as well as the code the fputs the lower file when all eCryptfs users are done with it. This patch is needed to fix issues, when mounted on top of the NFSv3 client, where the lower file is left silly renamed until the eCryptfs inode is destroyed. Signed-off-by: Tyler Hicks --- fs/ecryptfs/ecryptfs_kernel.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs/ecryptfs/ecryptfs_kernel.h') diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index bd3cafd0949d..380bee1094c3 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -295,6 +295,8 @@ struct ecryptfs_crypt_stat { struct ecryptfs_inode_info { struct inode vfs_inode; struct inode *wii_inode; + struct mutex lower_file_mutex; + atomic_t lower_file_count; struct file *lower_file; struct ecryptfs_crypt_stat crypt_stat; }; @@ -757,7 +759,8 @@ int ecryptfs_privileged_open(struct file **lower_file, struct dentry *lower_dentry, struct vfsmount *lower_mnt, const struct cred *cred); -int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry); +int ecryptfs_get_lower_file(struct dentry *ecryptfs_dentry); +void ecryptfs_put_lower_file(struct inode *inode); int ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, size_t *packet_size, -- cgit v1.2.3 From 3aeb86ea4cd15f728147a3bd5469a205ada8c767 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 15 Mar 2011 14:54:00 -0500 Subject: eCryptfs: Handle failed metadata read in lookup When failing to read the lower file's crypto metadata during a lookup, eCryptfs must continue on without throwing an error. For example, there may be a plaintext file in the lower mount point that the user wants to delete through the eCryptfs mount. If an error is encountered while reading the metadata in lookup(), the eCryptfs inode's size could be incorrect. We must be sure to reread the plaintext inode size from the metadata when performing an open() or setattr(). The metadata is already being read in those paths, so this adds minimal performance overhead. This patch introduces a flag which will track whether or not the plaintext inode size has been read so that an incorrect i_size can be fixed in the open() or setattr() paths. https://bugs.launchpad.net/bugs/509180 Cc: Signed-off-by: Tyler Hicks --- fs/ecryptfs/crypto.c | 21 +++++++++++++++++++++ fs/ecryptfs/ecryptfs_kernel.h | 2 ++ fs/ecryptfs/file.c | 3 ++- fs/ecryptfs/inode.c | 18 +++--------------- 4 files changed, 28 insertions(+), 16 deletions(-) (limited to 'fs/ecryptfs/ecryptfs_kernel.h') diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index d2a70a4561f9..b8d5c8091024 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1452,6 +1452,25 @@ static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; } +void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) +{ + struct ecryptfs_mount_crypt_stat *mount_crypt_stat; + struct ecryptfs_crypt_stat *crypt_stat; + u64 file_size; + + crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; + mount_crypt_stat = + &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; + if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { + file_size = i_size_read(ecryptfs_inode_to_lower(inode)); + if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) + file_size += crypt_stat->metadata_size; + } else + file_size = get_unaligned_be64(page_virt); + i_size_write(inode, (loff_t)file_size); + crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; +} + /** * ecryptfs_read_headers_virt * @page_virt: The virtual address into which to read the headers @@ -1482,6 +1501,8 @@ static int ecryptfs_read_headers_virt(char *page_virt, rc = -EINVAL; goto out; } + if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) + ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode); offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read); diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index 380bee1094c3..e70282775e2c 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -269,6 +269,7 @@ struct ecryptfs_crypt_stat { #define ECRYPTFS_ENCFN_USE_MOUNT_FNEK 0x00000800 #define ECRYPTFS_ENCFN_USE_FEK 0x00001000 #define ECRYPTFS_UNLINK_SIGS 0x00002000 +#define ECRYPTFS_I_SIZE_INITIALIZED 0x00004000 u32 flags; unsigned int file_version; size_t iv_bytes; @@ -628,6 +629,7 @@ struct ecryptfs_open_req { int ecryptfs_interpose(struct dentry *hidden_dentry, struct dentry *this_dentry, struct super_block *sb, u32 flags); +void ecryptfs_i_size_init(const char *page_virt, struct inode *inode); int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry, struct dentry *lower_dentry, struct inode *ecryptfs_dir_inode); diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index 146c4edff70c..566e5472f78c 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -235,7 +235,8 @@ static int ecryptfs_open(struct inode *inode, struct file *file) goto out_put; } rc = 0; - crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); + crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED + | ECRYPTFS_ENCRYPTED); mutex_unlock(&crypt_stat->cs_mutex); goto out; } diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index f6b388638c3d..2c19d362d2d4 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -225,10 +225,8 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry, struct dentry *lower_dir_dentry; struct vfsmount *lower_mnt; struct inode *lower_inode; - struct ecryptfs_mount_crypt_stat *mount_crypt_stat; struct ecryptfs_crypt_stat *crypt_stat; char *page_virt = NULL; - u64 file_size; int put_lower = 0, rc = 0; lower_dir_dentry = lower_dentry->d_parent; @@ -302,18 +300,7 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry, } crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; } - mount_crypt_stat = &ecryptfs_superblock_to_private( - ecryptfs_dentry->d_sb)->mount_crypt_stat; - if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { - if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) - file_size = (crypt_stat->metadata_size - + i_size_read(lower_dentry->d_inode)); - else - file_size = i_size_read(lower_dentry->d_inode); - } else { - file_size = get_unaligned_be64(page_virt); - } - i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size); + ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode); out_free_kmem: kmem_cache_free(ecryptfs_header_cache_2, page_virt); goto out; @@ -937,7 +924,8 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) goto out; } rc = 0; - crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); + crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED + | ECRYPTFS_ENCRYPTED); } } mutex_unlock(&crypt_stat->cs_mutex); -- cgit v1.2.3