ceph: save cap_auths in MDS client when session is opened

Save the cap_auths, which have been parsed by the MDS, in the opened
session.

[ idryomov: use s64 and u32 instead of int64_t and uint32_t, switch to
            bool for root_squash, readable and writeable ]

Link: https://tracker.ceph.com/issues/61333
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

2 files changed, 126 insertions, 1 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 360b686c3c67..6a1e68549475 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4112,10 +4112,13 @@ static void handle_session(struct ceph_mds_session *session,
 	void *p = msg->front.iov_base;
 	void *end = p + msg->front.iov_len;
 	struct ceph_mds_session_head *h;
-	u32 op;
+	struct ceph_mds_cap_auth *cap_auths = NULL;
+	u32 op, cap_auths_num = 0;
 	u64 seq, features = 0;
 	int wake = 0;
 	bool blocklisted = false;
+	u32 i;
+
 
 	/* decode */
 	ceph_decode_need(&p, end, sizeof(*h), bad);
@@ -4160,7 +4163,101 @@ static void handle_session(struct ceph_mds_session *session,
 		}
 	}
 
+	if (msg_version >= 6) {
+		ceph_decode_32_safe(&p, end, cap_auths_num, bad);
+		doutc(cl, "cap_auths_num %d\n", cap_auths_num);
+
+		if (cap_auths_num && op != CEPH_SESSION_OPEN) {
+			WARN_ON_ONCE(op != CEPH_SESSION_OPEN);
+			goto skip_cap_auths;
+		}
+
+		cap_auths = kcalloc(cap_auths_num,
+				    sizeof(struct ceph_mds_cap_auth),
+				    GFP_KERNEL);
+		if (!cap_auths) {
+			pr_err_client(cl, "No memory for cap_auths\n");
+			return;
+		}
+
+		for (i = 0; i < cap_auths_num; i++) {
+			u32 _len, j;
+
+			/* struct_v, struct_compat, and struct_len in MDSCapAuth */
+			ceph_decode_skip_n(&p, end, 2 + sizeof(u32), bad);
+
+			/* struct_v, struct_compat, and struct_len in MDSCapMatch */
+			ceph_decode_skip_n(&p, end, 2 + sizeof(u32), bad);
+			ceph_decode_64_safe(&p, end, cap_auths[i].match.uid, bad);
+			ceph_decode_32_safe(&p, end, _len, bad);
+			if (_len) {
+				cap_auths[i].match.gids = kcalloc(_len, sizeof(u32),
+								  GFP_KERNEL);
+				if (!cap_auths[i].match.gids) {
+					pr_err_client(cl, "No memory for gids\n");
+					goto fail;
+				}
+
+				cap_auths[i].match.num_gids = _len;
+				for (j = 0; j < _len; j++)
+					ceph_decode_32_safe(&p, end,
+							    cap_auths[i].match.gids[j],
+							    bad);
+			}
+
+			ceph_decode_32_safe(&p, end, _len, bad);
+			if (_len) {
+				cap_auths[i].match.path = kcalloc(_len + 1, sizeof(char),
+								  GFP_KERNEL);
+				if (!cap_auths[i].match.path) {
+					pr_err_client(cl, "No memory for path\n");
+					goto fail;
+				}
+				ceph_decode_copy(&p, cap_auths[i].match.path, _len);
+
+				/* Remove the tailing '/' */
+				while (_len && cap_auths[i].match.path[_len - 1] == '/') {
+					cap_auths[i].match.path[_len - 1] = '\0';
+					_len -= 1;
+				}
+			}
+
+			ceph_decode_32_safe(&p, end, _len, bad);
+			if (_len) {
+				cap_auths[i].match.fs_name = kcalloc(_len + 1, sizeof(char),
+								     GFP_KERNEL);
+				if (!cap_auths[i].match.fs_name) {
+					pr_err_client(cl, "No memory for fs_name\n");
+					goto fail;
+				}
+				ceph_decode_copy(&p, cap_auths[i].match.fs_name, _len);
+			}
+
+			ceph_decode_8_safe(&p, end, cap_auths[i].match.root_squash, bad);
+			ceph_decode_8_safe(&p, end, cap_auths[i].readable, bad);
+			ceph_decode_8_safe(&p, end, cap_auths[i].writeable, bad);
+			doutc(cl, "uid %lld, num_gids %u, path %s, fs_name %s, root_squash %d, readable %d, writeable %d\n",
+			      cap_auths[i].match.uid, cap_auths[i].match.num_gids,
+			      cap_auths[i].match.path, cap_auths[i].match.fs_name,
+			      cap_auths[i].match.root_squash,
+			      cap_auths[i].readable, cap_auths[i].writeable);
+		}
+	}
+
+skip_cap_auths:
 	mutex_lock(&mdsc->mutex);
+	if (op == CEPH_SESSION_OPEN) {
+		if (mdsc->s_cap_auths) {
+			for (i = 0; i < mdsc->s_cap_auths_num; i++) {
+				kfree(mdsc->s_cap_auths[i].match.gids);
+				kfree(mdsc->s_cap_auths[i].match.path);
+				kfree(mdsc->s_cap_auths[i].match.fs_name);
+			}
+			kfree(mdsc->s_cap_auths);
+		}
+		mdsc->s_cap_auths_num = cap_auths_num;
+		mdsc->s_cap_auths = cap_auths;
+	}
 	if (op == CEPH_SESSION_CLOSE) {
 		ceph_get_mds_session(session);
 		__unregister_session(mdsc, session);
@@ -4290,6 +4387,13 @@ bad:
 	pr_err_client(cl, "corrupt message mds%d len %d\n", mds,
 		      (int)msg->front.iov_len);
 	ceph_msg_dump(msg);
+fail:
+	for (i = 0; i < cap_auths_num; i++) {
+		kfree(cap_auths[i].match.gids);
+		kfree(cap_auths[i].match.path);
+		kfree(cap_auths[i].match.fs_name);
+	}
+	kfree(cap_auths);
 	return;
 }
 
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index b88e80415224..cc106f1aa7d2 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -71,6 +71,24 @@ enum ceph_feature_type {
 struct ceph_fs_client;
 struct ceph_cap;
 
+#define MDS_AUTH_UID_ANY -1
+
+struct ceph_mds_cap_match {
+	s64 uid;  /* default to MDS_AUTH_UID_ANY */
+	u32 num_gids;
+	u32 *gids;  /* use these GIDs */
+	char *path;  /* require path to be child of this
+			(may be "" or "/" for any) */
+	char *fs_name;
+	bool root_squash;  /* default to false */
+};
+
+struct ceph_mds_cap_auth {
+	struct ceph_mds_cap_match match;
+	bool readable;
+	bool writeable;
+};
+
 /*
  * parsed info about a single inode.  pointers are into the encoded
  * on-wire structures within the mds reply message payload.
@@ -513,6 +531,9 @@ struct ceph_mds_client {
 	struct rw_semaphore     pool_perm_rwsem;
 	struct rb_root		pool_perm_tree;
 
+	u32			 s_cap_auths_num;
+	struct ceph_mds_cap_auth *s_cap_auths;
+
 	char nodename[__NEW_UTS_LEN + 1];
 };