@@ -2923,6 +2923,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
{
int mds = session->s_mds;
struct ceph_mds_client *mdsc = session->s_mdsc;
+ struct ceph_client *cl = mdsc->fsc->client;
struct ceph_msg *msg;
struct ceph_mds_request_head_legacy *lhead;
const char *path1 = NULL;
@@ -3028,6 +3029,16 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
lhead = find_legacy_request_head(msg->front.iov_base,
session->s_con.peer_features);
+ if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
+ !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
+ pr_err_ratelimited_client(cl,
+ "idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
+ " is not supported by MDS. Fail request with -EIO.\n");
+
+ ret = -EIO;
+ goto out_err;
+ }
+
/*
* The ceph_mds_request_head_legacy didn't contain a version field, and
* one was added when we moved the message version from 3->4.
@@ -3043,10 +3054,19 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
p = msg->front.iov_base + sizeof(*ohead);
} else {
struct ceph_mds_request_head *nhead = msg->front.iov_base;
+ kuid_t owner_fsuid;
+ kgid_t owner_fsgid;
msg->hdr.version = cpu_to_le16(6);
nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
p = msg->front.iov_base + sizeof(*nhead);
+
+ owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
+ VFSUIDT_INIT(req->r_cred->fsuid));
+ owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
+ VFSGIDT_INIT(req->r_cred->fsgid));
+ nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
+ nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
}
end = msg->front.iov_base + msg->front.iov_len;
@@ -33,8 +33,10 @@ enum ceph_feature_type {
CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
CEPHFS_FEATURE_OP_GETVXATTR,
CEPHFS_FEATURE_32BITS_RETRY_FWD,
+ CEPHFS_FEATURE_NEW_SNAPREALM_INFO,
+ CEPHFS_FEATURE_HAS_OWNER_UIDGID,
- CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_32BITS_RETRY_FWD,
+ CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_HAS_OWNER_UIDGID,
};
#define CEPHFS_FEATURES_CLIENT_SUPPORTED { \
@@ -49,6 +51,7 @@ enum ceph_feature_type {
CEPHFS_FEATURE_NOTIFY_SESSION_STATE, \
CEPHFS_FEATURE_OP_GETVXATTR, \
CEPHFS_FEATURE_32BITS_RETRY_FWD, \
+ CEPHFS_FEATURE_HAS_OWNER_UIDGID, \
}
/*
@@ -499,7 +499,7 @@ struct ceph_mds_request_head_legacy {
union ceph_mds_request_args args;
} __attribute__ ((packed));
-#define CEPH_MDS_REQUEST_HEAD_VERSION 2
+#define CEPH_MDS_REQUEST_HEAD_VERSION 3
struct ceph_mds_request_head_old {
__le16 version; /* struct version */
@@ -530,6 +530,8 @@ struct ceph_mds_request_head {
__le32 ext_num_retry; /* new count retry attempts */
__le32 ext_num_fwd; /* new count fwd attempts */
+
+ __le32 owner_uid, owner_gid; /* used for OPs which create inodes */
} __attribute__ ((packed));
/* cap/lease release record */
Inode operations that create a new filesystem object such as ->mknod, ->create, ->mkdir() and others don't take a {g,u}id argument explicitly. Instead the caller's fs{g,u}id is used for the {g,u}id of the new filesystem object. In order to ensure that the correct {g,u}id is used map the caller's fs{g,u}id for creation requests. This doesn't require complex changes. It suffices to pass in the relevant idmapping recorded in the request message. If this request message was triggered from an inode operation that creates filesystem objects it will have passed down the relevant idmaping. If this is a request message that was triggered from an inode operation that doens't need to take idmappings into account the initial idmapping is passed down which is an identity mapping. This change uses a new cephfs protocol extension CEPHFS_FEATURE_HAS_OWNER_UIDGID which adds two new fields (owner_{u,g}id) to the request head structure. So, we need to ensure that MDS supports it otherwise we need to fail any IO that comes through an idmapped mount because we can't process it in a proper way. MDS server without such an extension will use caller_{u,g}id fields to set a new inode owner UID/GID which is incorrect because caller_{u,g}id values are unmapped. At the same time we can't map these fields with an idmapping as it can break UID/GID-based permission checks logic on the MDS side. This problem was described with a lot of details at [1], [2]. [1] https://lore.kernel.org/lkml/CAEivzxfw1fHO2TFA4dx3u23ZKK6Q+EThfzuibrhA3RKM=ZOYLg@mail.gmail.com/ [2] https://lore.kernel.org/all/20220104140414.155198-3-brauner@kernel.org/ Cc: Xiubo Li <xiubli@redhat.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: ceph-devel@vger.kernel.org Co-Developed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> --- v7: - reworked to use two new fields for owner UID/GID (https://github.com/ceph/ceph/pull/52575) --- fs/ceph/mds_client.c | 20 ++++++++++++++++++++ fs/ceph/mds_client.h | 5 ++++- include/linux/ceph/ceph_fs.h | 4 +++- 3 files changed, 27 insertions(+), 2 deletions(-)