Xiubo Li <xiubli@xxxxxxxxxx> writes:
> On 9/6/23 21:47, Luís Henriques wrote:
>> Since filenames in encrypted directories are encrypted and shown as
>> a base64-encoded string when the directory is locked, make snapshot
>> names show a similar behaviour.
>>
>> When creating a snapshot, .snap directories for every subdirectory will
>> show the snapshot name in the "long format":
>>
>> # mkdir .snap/my-snap
>> # ls my-dir/.snap/
>> _my-snap_1099511627782
>>
>> Encrypted snapshots will need to be able to handle these by
>> encrypting/decrypting only the snapshot part of the string ('my-snap').
>>
>> Also, since the MDS prevents snapshot names to be bigger than 240
>> characters it is necessary to adapt CEPH_NOHASH_NAME_MAX to accommodate
>> this extra limitation.
>>
>> [ idryomov: drop const on !CONFIG_FS_ENCRYPTION branch too ]
>>
>> Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>> Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
>> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
>> Reviewed-by: Xiubo Li <xiubli@xxxxxxxxxx>
>> Reviewed-by: Milind Changire <mchangir@xxxxxxxxxx>
>> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
>> ---
>> As reported by Dan Carpenter, the initial version of this patch wasn't
>> dealing correctly with the ceph_get_inode() return value: it never returns
>> NULL. Simply dropped the code that handled the case where a NULL was
>> being returned.
>>
>> Xiubo, can you please pick this new revision, if you think it's correct?
>
> Hi Luis,
>
> Please generate a new patch to fix this, the fscrypt corresponding commits have
> been merged already.
Yeah, I just realised it was too late for it. Which is great, I'm glad it
was too late, actually! :-)
Anyway, I'll send out a separate fix for this, so that it can be included
in -rc2.
Cheers,
--
Luís
>
> Thanks
>
> - Xiubo
>
>> And thanks, Dan!
>>
>> Cheers,
>> --
>> Luís
>>
>> fs/ceph/crypto.c | 195 +++++++++++++++++++++++++++++++++++++++--------
>> fs/ceph/crypto.h | 12 +--
>> fs/ceph/inode.c | 33 +++++++-
>> 3 files changed, 199 insertions(+), 41 deletions(-)
>>
>> diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
>> index 9494bf485f6a..7d0b9b5ccfc6 100644
>> --- a/fs/ceph/crypto.c
>> +++ b/fs/ceph/crypto.c
>> @@ -193,17 +193,99 @@ void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
>> swap(req->r_fscrypt_auth, as->fscrypt_auth);
>> }
>> -int ceph_encode_encrypted_dname(const struct inode *parent,
>> - struct qstr *d_name, char *buf)
>> +/*
>> + * User-created snapshots can't start with '_'. Snapshots that start with this
>> + * character are special (hint: there aren't real snapshots) and use the
>> + * following format:
>> + *
>> + * _<SNAPSHOT-NAME>_<INODE-NUMBER>
>> + *
>> + * where:
>> + * - <SNAPSHOT-NAME> - the real snapshot name that may need to be decrypted,
>> + * - <INODE-NUMBER> - the inode number (in decimal) for the actual snapshot
>> + *
>> + * This function parses these snapshot names and returns the inode
>> + * <INODE-NUMBER>. 'name_len' will also bet set with the <SNAPSHOT-NAME>
>> + * length.
>> + */
>> +static struct inode *parse_longname(const struct inode *parent,
>> + const char *name, int *name_len)
>> {
>> + struct inode *dir = NULL;
>> + struct ceph_vino vino = { .snap = CEPH_NOSNAP };
>> + char *inode_number;
>> + char *name_end;
>> + int orig_len = *name_len;
>> + int ret = -EIO;
>> +
>> + /* Skip initial '_' */
>> + name++;
>> + name_end = strrchr(name, '_');
>> + if (!name_end) {
>> + dout("Failed to parse long snapshot name: %s\n", name);
>> + return ERR_PTR(-EIO);
>> + }
>> + *name_len = (name_end - name);
>> + if (*name_len <= 0) {
>> + pr_err("Failed to parse long snapshot name\n");
>> + return ERR_PTR(-EIO);
>> + }
>> +
>> + /* Get the inode number */
>> + inode_number = kmemdup_nul(name_end + 1,
>> + orig_len - *name_len - 2,
>> + GFP_KERNEL);
>> + if (!inode_number)
>> + return ERR_PTR(-ENOMEM);
>> + ret = kstrtou64(inode_number, 10, &vino.ino);
>> + if (ret) {
>> + dout("Failed to parse inode number: %s\n", name);
>> + dir = ERR_PTR(ret);
>> + goto out;
>> + }
>> +
>> + /* And finally the inode */
>> + dir = ceph_find_inode(parent->i_sb, vino);
>> + if (!dir) {
>> + /* This can happen if we're not mounting cephfs on the root */
>> + dir = ceph_get_inode(parent->i_sb, vino, NULL);
>> + }
>> + if (IS_ERR(dir))
>> + dout("Can't find inode %s (%s)\n", inode_number, name);
>> +
>> +out:
>> + kfree(inode_number);
>> + return dir;
>> +}
>> +
>> +int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name,
>> + char *buf)
>> +{
>> + struct inode *dir = parent;
>> + struct qstr iname;
>> u32 len;
>> + int name_len;
>> int elen;
>> int ret;
>> - u8 *cryptbuf;
>> + u8 *cryptbuf = NULL;
>> +
>> + iname.name = d_name->name;
>> + name_len = d_name->len;
>> +
>> + /* Handle the special case of snapshot names that start with '_' */
>> + if ((ceph_snap(dir) == CEPH_SNAPDIR) && (name_len > 0) &&
>> + (iname.name[0] == '_')) {
>> + dir = parse_longname(parent, iname.name, &name_len);
>> + if (IS_ERR(dir))
>> + return PTR_ERR(dir);
>> + iname.name++; /* skip initial '_' */
>> + }
>> + iname.len = name_len;
>> - if (!fscrypt_has_encryption_key(parent)) {
>> + if (!fscrypt_has_encryption_key(dir)) {
>> memcpy(buf, d_name->name, d_name->len);
>> - return d_name->len;
>> + elen = d_name->len;
>> + goto out;
>> }
>> /*
>> @@ -212,19 +294,23 @@ int ceph_encode_encrypted_dname(const struct inode *parent,
>> *
>> * See: fscrypt_setup_filename
>> */
>> - if (!fscrypt_fname_encrypted_size(parent, d_name->len, NAME_MAX, &len))
>> - return -ENAMETOOLONG;
>> + if (!fscrypt_fname_encrypted_size(dir, iname.len, NAME_MAX, &len)) {
>> + elen = -ENAMETOOLONG;
>> + goto out;
>> + }
>> /* Allocate a buffer appropriate to hold the result */
>> cryptbuf = kmalloc(len > CEPH_NOHASH_NAME_MAX ? NAME_MAX : len,
>> GFP_KERNEL);
>> - if (!cryptbuf)
>> - return -ENOMEM;
>> + if (!cryptbuf) {
>> + elen = -ENOMEM;
>> + goto out;
>> + }
>> - ret = fscrypt_fname_encrypt(parent, d_name, cryptbuf, len);
>> + ret = fscrypt_fname_encrypt(dir, &iname, cryptbuf, len);
>> if (ret) {
>> - kfree(cryptbuf);
>> - return ret;
>> + elen = ret;
>> + goto out;
>> }
>> /* hash the end if the name is long enough */
>> @@ -243,13 +329,31 @@ int ceph_encode_encrypted_dname(const struct inode *parent,
>> /* base64 encode the encrypted name */
>> elen = ceph_base64_encode(cryptbuf, len, buf);
>> - kfree(cryptbuf);
>> dout("base64-encoded ciphertext name = %.*s\n", elen, buf);
>> +
>> + /* To understand the 240 limit, see CEPH_NOHASH_NAME_MAX comments */
>> + WARN_ON(elen > 240);
>> + if ((elen > 0) && (dir != parent)) {
>> + char tmp_buf[NAME_MAX];
>> +
>> + elen = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld",
>> + elen, buf, dir->i_ino);
>> + memcpy(buf, tmp_buf, elen);
>> + }
>> +
>> +out:
>> + kfree(cryptbuf);
>> + if (dir != parent) {
>> + if ((dir->i_state & I_NEW))
>> + discard_new_inode(dir);
>> + else
>> + iput(dir);
>> + }
>> return elen;
>> }
>> -int ceph_encode_encrypted_fname(const struct inode *parent,
>> - struct dentry *dentry, char *buf)
>> +int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentry,
>> + char *buf)
>> {
>> WARN_ON_ONCE(!fscrypt_has_encryption_key(parent));
>> @@ -274,29 +378,42 @@ int ceph_encode_encrypted_fname(const struct inode
>> *parent,
>> int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
>> struct fscrypt_str *oname, bool *is_nokey)
>> {
>> - int ret;
>> + struct inode *dir = fname->dir;
>> struct fscrypt_str _tname = FSTR_INIT(NULL, 0);
>> struct fscrypt_str iname;
>> -
>> - if (!IS_ENCRYPTED(fname->dir)) {
>> - oname->name = fname->name;
>> - oname->len = fname->name_len;
>> - return 0;
>> - }
>> + char *name = fname->name;
>> + int name_len = fname->name_len;
>> + int ret;
>> /* Sanity check that the resulting name will fit in the buffer */
>> if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX)
>> return -EIO;
>> - ret = ceph_fscrypt_prepare_readdir(fname->dir);
>> - if (ret < 0)
>> - return ret;
>> + /* Handle the special case of snapshot names that start with '_' */
>> + if ((ceph_snap(dir) == CEPH_SNAPDIR) && (name_len > 0) &&
>> + (name[0] == '_')) {
>> + dir = parse_longname(dir, name, &name_len);
>> + if (IS_ERR(dir))
>> + return PTR_ERR(dir);
>> + name++; /* skip initial '_' */
>> + }
>> +
>> + if (!IS_ENCRYPTED(dir)) {
>> + oname->name = fname->name;
>> + oname->len = fname->name_len;
>> + ret = 0;
>> + goto out_inode;
>> + }
>> +
>> + ret = ceph_fscrypt_prepare_readdir(dir);
>> + if (ret)
>> + goto out_inode;
>> /*
>> * Use the raw dentry name as sent by the MDS instead of
>> * generating a nokey name via fscrypt.
>> */
>> - if (!fscrypt_has_encryption_key(fname->dir)) {
>> + if (!fscrypt_has_encryption_key(dir)) {
>> if (fname->no_copy)
>> oname->name = fname->name;
>> else
>> @@ -304,7 +421,8 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
>> oname->len = fname->name_len;
>> if (is_nokey)
>> *is_nokey = true;
>> - return 0;
>> + ret = 0;
>> + goto out_inode;
>> }
>> if (fname->ctext_len == 0) {
>> @@ -313,12 +431,11 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
>> if (!tname) {
>> ret = fscrypt_fname_alloc_buffer(NAME_MAX, &_tname);
>> if (ret)
>> - return ret;
>> + goto out_inode;
>> tname = &_tname;
>> }
>> - declen = ceph_base64_decode(fname->name, fname->name_len,
>> - tname->name);
>> + declen = ceph_base64_decode(name, name_len, tname->name);
>> if (declen <= 0) {
>> ret = -EIO;
>> goto out;
>> @@ -330,9 +447,25 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
>> iname.len = fname->ctext_len;
>> }
>> - ret = fscrypt_fname_disk_to_usr(fname->dir, 0, 0, &iname, oname);
>> + ret = fscrypt_fname_disk_to_usr(dir, 0, 0, &iname, oname);
>> + if (!ret && (dir != fname->dir)) {
>> + char tmp_buf[CEPH_BASE64_CHARS(NAME_MAX)];
>> +
>> + name_len = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld",
>> + oname->len, oname->name, dir->i_ino);
>> + memcpy(oname->name, tmp_buf, name_len);
>> + oname->len = name_len;
>> + }
>> +
>> out:
>> fscrypt_fname_free_buffer(&_tname);
>> +out_inode:
>> + if ((dir != fname->dir) && !IS_ERR(dir)) {
>> + if ((dir->i_state & I_NEW))
>> + discard_new_inode(dir);
>> + else
>> + iput(dir);
>> + }
>> return ret;
>> }
>> diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
>> index 6afa6d888fe0..47e0c319fc68 100644
>> --- a/fs/ceph/crypto.h
>> +++ b/fs/ceph/crypto.h
>> @@ -102,10 +102,10 @@ int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
>> struct ceph_acl_sec_ctx *as);
>> void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
>> struct ceph_acl_sec_ctx *as);
>> -int ceph_encode_encrypted_dname(const struct inode *parent,
>> - struct qstr *d_name, char *buf);
>> -int ceph_encode_encrypted_fname(const struct inode *parent,
>> - struct dentry *dentry, char *buf);
>> +int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name,
>> + char *buf);
>> +int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentry,
>> + char *buf);
>> static inline int ceph_fname_alloc_buffer(struct inode *parent,
>> struct fscrypt_str *fname)
>> @@ -194,14 +194,14 @@ static inline void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
>> {
>> }
>> -static inline int ceph_encode_encrypted_dname(const struct inode *parent,
>> +static inline int ceph_encode_encrypted_dname(struct inode *parent,
>> struct qstr *d_name, char *buf)
>> {
>> memcpy(buf, d_name->name, d_name->len);
>> return d_name->len;
>> }
>> -static inline int ceph_encode_encrypted_fname(const struct inode *parent,
>> +static inline int ceph_encode_encrypted_fname(struct inode *parent,
>> struct dentry *dentry, char *buf)
>> {
>> return -EOPNOTSUPP;
>> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
>> index 054fd66609b7..83c420646f90 100644
>> --- a/fs/ceph/inode.c
>> +++ b/fs/ceph/inode.c
>> @@ -91,9 +91,15 @@ struct inode *ceph_new_inode(struct inode *dir, struct dentry *dentry,
>> if (err < 0)
>> goto out_err;
>> - err = ceph_fscrypt_prepare_context(dir, inode, as_ctx);
>> - if (err)
>> - goto out_err;
>> + /*
>> + * We'll skip setting fscrypt context for snapshots, leaving that for
>> + * the handle_reply().
>> + */
>> + if (ceph_snap(dir) != CEPH_SNAPDIR) {
>> + err = ceph_fscrypt_prepare_context(dir, inode, as_ctx);
>> + if (err)
>> + goto out_err;
>> + }
>> return inode;
>> out_err:
>> @@ -159,6 +165,7 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>> };
>> struct inode *inode = ceph_get_inode(parent->i_sb, vino, NULL);
>> struct ceph_inode_info *ci = ceph_inode(inode);
>> + int ret = -ENOTDIR;
>> if (IS_ERR(inode))
>> return inode;
>> @@ -184,6 +191,24 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>> ci->i_rbytes = 0;
>> ci->i_btime = ceph_inode(parent)->i_btime;
>> +#ifdef CONFIG_FS_ENCRYPTION
>> + /* if encrypted, just borrow fscrypt_auth from parent */
>> + if (IS_ENCRYPTED(parent)) {
>> + struct ceph_inode_info *pci = ceph_inode(parent);
>> +
>> + ci->fscrypt_auth = kmemdup(pci->fscrypt_auth,
>> + pci->fscrypt_auth_len,
>> + GFP_KERNEL);
>> + if (ci->fscrypt_auth) {
>> + inode->i_flags |= S_ENCRYPTED;
>> + ci->fscrypt_auth_len = pci->fscrypt_auth_len;
>> + } else {
>> + dout("Failed to alloc snapdir fscrypt_auth\n");
>> + ret = -ENOMEM;
>> + goto err;
>> + }
>> + }
>> +#endif
>> if (inode->i_state & I_NEW) {
>> inode->i_op = &ceph_snapdir_iops;
>> inode->i_fop = &ceph_snapdir_fops;
>> @@ -197,7 +222,7 @@ struct inode *ceph_get_snapdir(struct inode *parent)
>> discard_new_inode(inode);
>> else
>> iput(inode);
>> - return ERR_PTR(-ENOTDIR);
>> + return ERR_PTR(ret);
>> }
>> const struct inode_operations ceph_file_iops = {
>>
>
