APPLIED: Lucid SRU: eCryptfs: Handle failed metadata read in lookup
Tim Gardner
tim.gardner at canonical.com
Wed Jul 20 20:17:43 UTC 2011
On 07/19/2011 04:53 PM, Tim Gardner wrote:
> The following changes since commit b9d52a294afd689b987ab0855a86a871d0a48618:
> Greg Kroah-Hartman (1):
> Linux 2.6.32.43
>
> are available in the git repository at:
>
> git://kernel.ubuntu.com/rtg/ubuntu-lucid.git ecryptfs-lp509180
>
> Tim Gardner (1):
> eCryptfs: Handle failed metadata read in lookup
>
> 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(-)
>
> From 2afbc1dca9a944e10434ddbe90b0c94521464475 Mon Sep 17 00:00:00 2001
> From: Tim Gardner<tim.gardner at canonical.com>
> Date: Tue, 19 Jul 2011 17:44:22 -0600
> Subject: [PATCH] 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:<stable at kernel.org>
> Signed-off-by: Tyler Hicks<tyhicks at linux.vnet.ibm.com>
>
> (backported from 3aeb86ea4cd15f728147a3bd5469a205ada8c767)
> Signed-off-by: Tim Gardner<tim.gardner at canonical.com>
> ---
> 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(-)
>
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index 7cb0a59..e915eb1 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -1455,6 +1455,25 @@ static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
> 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
> @@ -1485,6 +1504,8 @@ 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 542f625..9685315 100644
> --- a/fs/ecryptfs/ecryptfs_kernel.h
> +++ b/fs/ecryptfs/ecryptfs_kernel.h
> @@ -270,6 +270,7 @@ struct ecryptfs_crypt_stat {
> #define ECRYPTFS_ENCFN_USE_MOUNT_FNEK 0x00001000
> #define ECRYPTFS_ENCFN_USE_FEK 0x00002000
> #define ECRYPTFS_UNLINK_SIGS 0x00004000
> +#define ECRYPTFS_I_SIZE_INITIALIZED 0x00008000
> u32 flags;
> unsigned int file_version;
> size_t iv_bytes;
> @@ -619,6 +620,7 @@ 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 4e25328..eb744ed 100644
> --- a/fs/ecryptfs/file.c
> +++ b/fs/ecryptfs/file.c
> @@ -237,7 +237,8 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
> goto out_free;
> }
> 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 88ba4d4..5bab1c5 100644
> --- a/fs/ecryptfs/inode.c
> +++ b/fs/ecryptfs/inode.c
> @@ -256,10 +256,8 @@ 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 rc = 0;
>
> lower_dir_dentry = lower_dentry->d_parent;
> @@ -334,18 +332,7 @@ 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->num_header_bytes_at_front
> - + 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;
> @@ -925,7 +912,8 @@ 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);
--
Tim Gardner tim.gardner at canonical.com
More information about the kernel-team
mailing list