Xiubo Li <xiubli@xxxxxxxxxx> writes:
> On 2/24/22 7:21 PM, Luís Henriques wrote:
>> Since filenames in encrypted directories are already encrypted and shown
>> as a base64-encoded string when the directory is locked, snapshot names
>> should show a similar behaviour.
>>
>> Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
>> ---
>> fs/ceph/dir.c | 15 +++++++++++++++
>> fs/ceph/inode.c | 10 +++++++++-
>> 2 files changed, 24 insertions(+), 1 deletion(-)
>>
>> Support on the MDS for names that'll be > MAX_NAME when base64 encoded is
>> still TBD. I thought it would be something easy to do, but snapshots
>> don't seem to make use of the CDir/CDentry (which is where alternate_name
>> is stored on the MDS). I'm still looking into this, but I may need some
>> help there :-(
>
> Yeah, good catch. The snapshot handler in MDS hasn't handled this case yet,
> though the kclient has passed it to MDS server.
>
> The snapshot alternate_name raw ciphertext should be stored in SnapInfo struct
> along with the 'name'.
>
>
>>
>> Cheers,
>> --
>> Luís
>>
>> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
>> index a449f4a07c07..20ae600ee7cd 100644
>> --- a/fs/ceph/dir.c
>> +++ b/fs/ceph/dir.c
>> @@ -1065,6 +1065,13 @@ static int ceph_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
>> op = CEPH_MDS_OP_MKSNAP;
>> dout("mksnap dir %p snap '%pd' dn %p\n", dir,
>> dentry, dentry);
>> + /* XXX missing support for alternate_name in snapshots */
>> + if (IS_ENCRYPTED(dir) && (dentry->d_name.len >= 189)) {
>> + dout("encrypted snapshot name too long: %pd len: %d\n",
>> + dentry, dentry->d_name.len);
>> + err = -ENAMETOOLONG;
>> + goto out;
>> + }
>
> We should fix the MDS side bug and then this workaroud will be no needed.
Yep, I've been looking into that too but it's taking a bit to understand
all that's going on there. I'm still trying, but the MDS code (and C++ in
general) is a bit... challenging.
Cheers,
--
Luís
>
> - Xiubo
>
>> } else if (ceph_snap(dir) == CEPH_NOSNAP) {
>> dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
>> op = CEPH_MDS_OP_MKDIR;
>> @@ -1109,6 +1116,14 @@ static int ceph_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
>> !req->r_reply_info.head->is_target &&
>> !req->r_reply_info.head->is_dentry)
>> err = ceph_handle_notrace_create(dir, dentry);
>> +
>> + /*
>> + * If we have created a snapshot we need to clear the cache, otherwise
>> + * snapshot will show encrypted filenames in readdir.
>> + */
>> + if (ceph_snap(dir) == CEPH_SNAPDIR)
>> + d_drop(dentry);
>> +
>> out_req:
>> ceph_mdsc_put_request(req);
>> out:
>> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
>> index 8b0832271fdf..080824610b73 100644
>> --- a/fs/ceph/inode.c
>> +++ b/fs/ceph/inode.c
>> @@ -182,6 +182,13 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>> ci->i_rbytes = 0;
>> ci->i_btime = ceph_inode(parent)->i_btime;
>> + /* if encrypted, just borough fscrypt_auth from parent */
>> + if (IS_ENCRYPTED(parent)) {
>> + struct ceph_inode_info *pci = ceph_inode(parent);
>> + inode->i_flags |= S_ENCRYPTED;
>> + ci->fscrypt_auth_len = pci->fscrypt_auth_len;
>> + ci->fscrypt_auth = pci->fscrypt_auth;
>> + }
>> if (inode->i_state & I_NEW) {
>> inode->i_op = &ceph_snapdir_iops;
>> inode->i_fop = &ceph_snapdir_fops;
>> @@ -632,7 +639,8 @@ void ceph_free_inode(struct inode *inode)
>> kfree(ci->i_symlink);
>> #ifdef CONFIG_FS_ENCRYPTION
>> - kfree(ci->fscrypt_auth);
>> + if (ceph_snap(inode) != CEPH_SNAPDIR)
>> + kfree(ci->fscrypt_auth);
>> #endif
>> fscrypt_free_inode(inode);
>> kmem_cache_free(ceph_inode_cachep, ci);
>>
>
