[RFC PATCH v5 17/19] ceph: add support to readdir for encrypted filenames

Jeff Layton
2021-03-26T17:33:45Z

Add helper functions for buffer management and for decrypting filenames
returned by the MDS. Wire those into the readdir codepaths.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/dir.c | 62 +++++++++++++++++++++++++++++++++++++++----------
fs/ceph/inode.c | 38 +++++++++++++++++++++++++++---
2 files changed, 85 insertions(+), 15 deletions(-)

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 867e396f44f1..7fe74c2f3911 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -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;
@@ -313,6 +316,8 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
int err;
unsigned frag = -1;
struct ceph_mds_reply_info_parsed *rinfo;
+ struct fscrypt_str tname = FSTR_INIT(NULL, 0);
+ struct fscrypt_str oname = FSTR_INIT(NULL, 0);

dout("readdir %p file %p pos %llx\n", inode, file, ctx->pos);
if (dfi->file_info.flags & CEPH_F_ATEND)
@@ -340,6 +345,10 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
ctx->pos = 2;
}

+ err = fscrypt_prepare_readdir(inode);
+ if (err)
+ goto out;
+
spin_lock(&ci->i_ceph_lock);
/* request Fx cap. if have Fx, we don't need to release Fs cap
* for later create/unlink. */
@@ -360,6 +369,14 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
spin_unlock(&ci->i_ceph_lock);
}

+ err = ceph_fname_alloc_buffer(inode, &tname);
+ if (err < 0)
+ goto out;
+
+ err = ceph_fname_alloc_buffer(inode, &oname);
+ if (err < 0)
+ goto out;
+
/* proceed with a normal readdir */
more:
/* do we have the correct frag content buffered? */
@@ -387,12 +404,14 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
dout("readdir fetching %llx.%llx frag %x offset '%s'\n",
ceph_vinop(inode), frag, dfi->last_name);
req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
- if (IS_ERR(req))
- return PTR_ERR(req);
+ if (IS_ERR(req)) {
+ err = PTR_ERR(req);
+ goto out;
+ }
err = ceph_alloc_readdir_reply_buffer(req, inode);
if (err) {
ceph_mdsc_put_request(req);
- return err;
+ goto out;
}
/* hints to request -> mds selection code */
req->r_direct_mode = USE_AUTH_MDS;
@@ -405,7 +424,8 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
req->r_path2 = kstrdup(dfi->last_name, GFP_KERNEL);
if (!req->r_path2) {
ceph_mdsc_put_request(req);
- return -ENOMEM;
+ err = -ENOMEM;
+ goto out;
}
} else if (is_hash_order(ctx->pos)) {
req->r_args.readdir.offset_hash =
@@ -426,7 +446,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
err = ceph_mdsc_do_request(mdsc, NULL, req);
if (err < 0) {
ceph_mdsc_put_request(req);
- return err;
+ goto out;
}
dout("readdir got and parsed readdir result=%d on "
"frag %x, end=%d, complete=%d, hash_order=%d\n",
@@ -479,7 +499,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
err = note_last_dentry(dfi, rde->name, rde->name_len,
next_offset);
if (err)
- return err;
+ goto out;
} else if (req->r_reply_info.dir_end) {
dfi->next_offset = 2;
/* keep last name */
@@ -507,22 +527,37 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
}
for (; i < rinfo->dir_nr; i++) {
struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
+ struct ceph_fname fname = { .dir = inode,
+ .name = rde->name,
+ .name_len = rde->name_len,
+ .ctext = rde->altname,
+ .ctext_len = rde->altname_len };
+ u32 olen = oname.len;

BUG_ON(rde->offset < ctx->pos);
+ BUG_ON(!rde->inode.in);

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);
+ err = ceph_fname_to_usr(&fname, &tname, &oname, NULL);
+ if (err) {
+ dout("Unable to decode %.*s. Skipping it.\n", rde->name_len, rde->name);
+ continue;
+ }

- if (!dir_emit(ctx, rde->name, rde->name_len,
+ if (!dir_emit(ctx, oname.name, oname.len,
ceph_present_ino(inode->i_sb, le64_to_cpu(rde->inode.in->ino)),
le32_to_cpu(rde->inode.in->mode) >> 12)) {
dout("filldir stopping us...\n");
- return 0;
+ err = 0;
+ goto out;
}
+
+ /* Reset the lengths to their original allocated vals */
+ oname.len = olen;
ctx->pos++;
}

@@ -577,9 +612,12 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
dfi->dir_ordered_count);
spin_unlock(&ci->i_ceph_lock);
}
-
+ err = 0;
dout("readdir %p file %p done.\n", inode, file);
- return 0;
+out:
+ ceph_fname_free_buffer(inode, &tname);
+ ceph_fname_free_buffer(inode, &oname);
+ return err;
}

static void reset_readdir(struct ceph_dir_file_info *dfi)
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 39f4c0dfa071..bf2760e53827 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1726,7 +1726,8 @@ 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;
@@ -1736,6 +1737,8 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
u32 last_hash = 0;
u32 fpos_offset;
struct ceph_readdir_cache_control cache_ctl = {};
+ struct fscrypt_str tname = FSTR_INIT(NULL, 0);
+ struct fscrypt_str oname = FSTR_INIT(NULL, 0);

if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
return readdir_prepopulate_inodes_only(req, session);
@@ -1787,14 +1790,36 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
cache_ctl.index = req->r_readdir_cache_idx;
fpos_offset = req->r_readdir_offset;

+ err = ceph_fname_alloc_buffer(inode, &tname);
+ if (err < 0)
+ goto out;
+
+ err = ceph_fname_alloc_buffer(inode, &oname);
+ if (err < 0)
+ goto out;
+
/* FIXME: release caps/leases if error occurs */
for (i = 0; i < rinfo->dir_nr; i++) {
+ bool is_nokey = false;
struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
struct ceph_vino tvino;
+ u32 olen = oname.len;
+ struct ceph_fname fname = { .dir = inode,
+ .name = rde->name,
+ .name_len = rde->name_len,
+ .ctext = rde->altname,
+ .ctext_len = rde->altname_len };
+
+ err = ceph_fname_to_usr(&fname, &tname, &oname, &is_nokey);
+ if (err) {
+ dout("Unable to decode %.*s. Skipping it.", rde->name_len, rde->name);
+ continue;
+ }

- dname.name = rde->name;
- dname.len = rde->name_len;
+ dname.name = oname.name;
+ dname.len = oname.len;
dname.hash = full_name_hash(parent, dname.name, dname.len);
+ oname.len = olen;

tvino.ino = le64_to_cpu(rde->inode.in->ino);
tvino.snap = le64_to_cpu(rde->inode.in->snapid);
@@ -1825,6 +1850,11 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
err = -ENOMEM;
goto out;
}
+ if (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)) {
@@ -1915,6 +1945,8 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
req->r_readdir_cache_idx = cache_ctl.index;
}
ceph_readdir_cache_release(&cache_ctl);
+ ceph_fname_free_buffer(inode, &tname);
+ ceph_fname_free_buffer(inode, &oname);
dout("readdir_prepopulate done\n");
return err;
}
--
2.30.2