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?
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 = {
