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ceph: add support to readdir for encrypted names 

To make it simpler to decrypt names in a readdir reply (i.e. before
we have a dentry), add a new ceph_encode_encrypted_fname()-like helper
that takes a qstr pointer instead of a dentry pointer.

Once we've decrypted the names in a readdir reply, we no longer need the
crypttext, so overwrite them in ceph_mds_reply_dir_entry with the
unencrypted names. Then in both ceph_readdir_prepopulate() and
ceph_readdir() we will use the dencrypted name directly.

[ jlayton: convert some BUG_ONs into error returns ]

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Xiubo Li 2022-03-14 10:28:35 +08:00 committed by Ilya Dryomov
parent 3859af9eba
commit af9ffa6df7
6 changed files with 144 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
fs/ceph/crypto.c
View File

@ -192,15 +192,18 @@ void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
swap(req->r_fscrypt_auth, as->fscrypt_auth);
}
int ceph_encode_encrypted_fname(const struct inode *parent,
struct dentry *dentry, char *buf)
int ceph_encode_encrypted_dname(const struct inode *parent,
struct qstr *d_name, char *buf)
{
u32 len;
int elen;
int ret;
u8 *cryptbuf;
WARN_ON_ONCE(!fscrypt_has_encryption_key(parent));
if (!fscrypt_has_encryption_key(parent)) {
memcpy(buf, d_name->name, d_name->len);
return d_name->len;
}
/*
* Convert cleartext d_name to ciphertext. If result is longer than
@ -208,8 +211,7 @@ int ceph_encode_encrypted_fname(const struct inode *parent,
*
* See: fscrypt_setup_filename
*/
if (!fscrypt_fname_encrypted_size(parent, dentry->d_name.len, NAME_MAX,
&len))
if (!fscrypt_fname_encrypted_size(parent, d_name->len, NAME_MAX, &len))
return -ENAMETOOLONG;
/* Allocate a buffer appropriate to hold the result */
@ -218,7 +220,7 @@ int ceph_encode_encrypted_fname(const struct inode *parent,
if (!cryptbuf)
return -ENOMEM;
ret = fscrypt_fname_encrypt(parent, &dentry->d_name, cryptbuf, len);
ret = fscrypt_fname_encrypt(parent, d_name, cryptbuf, len);
if (ret) {
kfree(cryptbuf);
return ret;
@ -245,6 +247,14 @@ int ceph_encode_encrypted_fname(const struct inode *parent,
return elen;
}
int ceph_encode_encrypted_fname(const struct inode *parent,
struct dentry *dentry, char *buf)
{
WARN_ON_ONCE(!fscrypt_has_encryption_key(parent));
return ceph_encode_encrypted_dname(parent, &dentry->d_name, buf);
}
/**
* ceph_fname_to_usr - convert a filename for userland presentation
* @fname: ceph_fname to be converted
@ -286,7 +296,10 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
* generating a nokey name via fscrypt.
*/
if (!fscrypt_has_encryption_key(fname->dir)) {
memcpy(oname->name, fname->name, fname->name_len);
if (fname->no_copy)
oname->name = fname->name;
else
memcpy(oname->name, fname->name, fname->name_len);
oname->len = fname->name_len;
if (is_nokey)
*is_nokey = true;

10
fs/ceph/crypto.h
View File

@ -19,6 +19,7 @@ struct ceph_fname {
unsigned char *ctext; // binary crypttext (if any)
u32 name_len; // length of name buffer
u32 ctext_len; // length of crypttext
bool no_copy;
};
struct ceph_fscrypt_auth {
@ -76,6 +77,8 @@ 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);
@ -121,6 +124,13 @@ 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,
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,
struct dentry *dentry, char *buf)
{

36
fs/ceph/dir.c
View File

@ -9,6 +9,7 @@
#include "super.h"
#include "mds_client.h"
#include "crypto.h"
/*
* Directory operations: readdir, lookup, create, link, unlink,
@ -241,7 +242,9 @@ static int __dcache_readdir(struct file *file, struct dir_context *ctx,
di = ceph_dentry(dentry);
if (d_unhashed(dentry) ||
d_really_is_negative(dentry) ||
di->lease_shared_gen != shared_gen) {
di->lease_shared_gen != shared_gen ||
((dentry->d_flags & DCACHE_NOKEY_NAME) &&
fscrypt_has_encryption_key(dir))) {
spin_unlock(&dentry->d_lock);
dput(dentry);
err = -EAGAIN;
@ -340,6 +343,10 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
ctx->pos = 2;
}
err = fscrypt_prepare_readdir(inode);
if (err)
return err;
spin_lock(&ci->i_ceph_lock);
/* request Fx cap. if have Fx, we don't need to release Fs cap
* for later create/unlink. */
@ -389,6 +396,7 @@ more:
req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
if (IS_ERR(req))
return PTR_ERR(req);
err = ceph_alloc_readdir_reply_buffer(req, inode);
if (err) {
ceph_mdsc_put_request(req);
@ -402,11 +410,21 @@ more:
req->r_inode_drop = CEPH_CAP_FILE_EXCL;
}
if (dfi->last_name) {
req->r_path2 = kstrdup(dfi->last_name, GFP_KERNEL);
struct qstr d_name = { .name = dfi->last_name,
.len = strlen(dfi->last_name) };
req->r_path2 = kzalloc(NAME_MAX + 1, GFP_KERNEL);
if (!req->r_path2) {
ceph_mdsc_put_request(req);
return -ENOMEM;
}
err = ceph_encode_encrypted_dname(inode, &d_name,
req->r_path2);
if (err < 0) {
ceph_mdsc_put_request(req);
return err;
}
} else if (is_hash_order(ctx->pos)) {
req->r_args.readdir.offset_hash =
cpu_to_le32(fpos_hash(ctx->pos));
@ -511,15 +529,20 @@ more:
for (; i < rinfo->dir_nr; i++) {
struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
BUG_ON(rde->offset < ctx->pos);
if (rde->offset < ctx->pos) {
pr_warn("%s: rde->offset 0x%llx ctx->pos 0x%llx\n",
__func__, rde->offset, ctx->pos);
return -EIO;
}
if (WARN_ON_ONCE(!rde->inode.in))
return -EIO;
ctx->pos = rde->offset;
dout("readdir (%d/%d) -> %llx '%.*s' %p\n",
i, rinfo->dir_nr, ctx->pos,
rde->name_len, rde->name, &rde->inode.in);
BUG_ON(!rde->inode.in);
if (!dir_emit(ctx, rde->name, rde->name_len,
ceph_present_ino(inode->i_sb, le64_to_cpu(rde->inode.in->ino)),
le32_to_cpu(rde->inode.in->mode) >> 12)) {
@ -532,6 +555,8 @@ more:
dout("filldir stopping us...\n");
return 0;
}
/* Reset the lengths to their original allocated vals */
ctx->pos++;
}
@ -586,7 +611,6 @@ more:
dfi->dir_ordered_count);
spin_unlock(&ci->i_ceph_lock);
}
dout("readdir %p file %p done.\n", inode, file);
return 0;
}

12
fs/ceph/inode.c
View File

@ -1752,7 +1752,8 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
struct ceph_mds_session *session)
{
struct dentry *parent = req->r_dentry;
struct ceph_inode_info *ci = ceph_inode(d_inode(parent));
struct inode *inode = d_inode(parent);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
struct qstr dname;
struct dentry *dn;
@ -1826,9 +1827,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
tvino.snap = le64_to_cpu(rde->inode.in->snapid);
if (rinfo->hash_order) {
u32 hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
rde->name, rde->name_len);
hash = ceph_frag_value(hash);
u32 hash = ceph_frag_value(rde->raw_hash);
if (hash != last_hash)
fpos_offset = 2;
last_hash = hash;
@ -1851,6 +1850,11 @@ retry_lookup:
err = -ENOMEM;
goto out;
}
if (rde->is_nokey) {
spin_lock(&dn->d_lock);
dn->d_flags |= DCACHE_NOKEY_NAME;
spin_unlock(&dn->d_lock);
}
} else if (d_really_is_positive(dn) &&
(ceph_ino(d_inode(dn)) != tvino.ino ||
ceph_snap(d_inode(dn)) != tvino.snap)) {

81
fs/ceph/mds_client.c
View File

@ -440,20 +440,87 @@ static int parse_reply_info_readdir(void **p, void *end,
info->dir_nr = num;
while (num) {
struct inode *inode = d_inode(req->r_dentry);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i;
struct fscrypt_str tname = FSTR_INIT(NULL, 0);
struct fscrypt_str oname = FSTR_INIT(NULL, 0);
struct ceph_fname fname;
u32 altname_len, _name_len;
u8 *altname, *_name;
/* dentry */
ceph_decode_32_safe(p, end, rde->name_len, bad);
ceph_decode_need(p, end, rde->name_len, bad);
rde->name = *p;
*p += rde->name_len;
dout("parsed dir dname '%.*s'\n", rde->name_len, rde->name);
ceph_decode_32_safe(p, end, _name_len, bad);
ceph_decode_need(p, end, _name_len, bad);
_name = *p;
*p += _name_len;
dout("parsed dir dname '%.*s'\n", _name_len, _name);
if (info->hash_order)
rde->raw_hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
_name, _name_len);
/* dentry lease */
err = parse_reply_info_lease(p, end, &rde->lease, features,
&rde->altname_len, &rde->altname);
&altname_len, &altname);
if (err)
goto out_bad;
/*
* Try to dencrypt the dentry names and update them
* in the ceph_mds_reply_dir_entry struct.
*/
fname.dir = inode;
fname.name = _name;
fname.name_len = _name_len;
fname.ctext = altname;
fname.ctext_len = altname_len;
/*
* The _name_len maybe larger than altname_len, such as
* when the human readable name length is in range of
* (CEPH_NOHASH_NAME_MAX, CEPH_NOHASH_NAME_MAX + SHA256_DIGEST_SIZE),
* then the copy in ceph_fname_to_usr will corrupt the
* data if there has no encryption key.
*
* Just set the no_copy flag and then if there has no
* encryption key the oname.name will be assigned to
* _name always.
*/
fname.no_copy = true;
if (altname_len == 0) {
/*
* Set tname to _name, and this will be used
* to do the base64_decode in-place. It's
* safe because the decoded string should
* always be shorter, which is 3/4 of origin
* string.
*/
tname.name = _name;
/*
* Set oname to _name too, and this will be
* used to do the dencryption in-place.
*/
oname.name = _name;
oname.len = _name_len;
} else {
/*
* This will do the decryption only in-place
* from altname cryptext directly.
*/
oname.name = altname;
oname.len = altname_len;
}
rde->is_nokey = false;
err = ceph_fname_to_usr(&fname, &tname, &oname, &rde->is_nokey);
if (err) {
pr_err("%s unable to decode %.*s, got %d\n", __func__,
_name_len, _name, err);
goto out_bad;
}
rde->name = oname.name;
rde->name_len = oname.len;
/* inode */
err = parse_reply_info_in(p, end, &rde->inode, features);
if (err < 0)
@ -3671,7 +3738,7 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
if (err == 0) {
if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
req->r_op == CEPH_MDS_OP_LSSNAP))
ceph_readdir_prepopulate(req, req->r_session);
err = ceph_readdir_prepopulate(req, req->r_session);
}
current->journal_info = NULL;
mutex_unlock(&req->r_fill_mutex);

4
fs/ceph/mds_client.h
View File

@ -96,10 +96,10 @@ struct ceph_mds_reply_info_in {
};
struct ceph_mds_reply_dir_entry {
bool is_nokey;
char *name;
u8 *altname;
u32 name_len;
u32 altname_len;
u32 raw_hash;
struct ceph_mds_reply_lease *lease;
struct ceph_mds_reply_info_in inode;
loff_t offset;