libceph: wrap auth methods in a mutex

The auth code is called from a variety of contexts, include the mon_client
(protected by the monc's mutex) and the messenger callbacks (currently
protected by nothing).  Avoid chaos by protecting all auth state with a
mutex.  Nothing is blocking, so this should be simple and lightweight.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>

2 files changed, 58 insertions, 22 deletions

diff --git a/include/linux/ceph/auth.h b/include/linux/ceph/auth.h
index c9c3b3abe4a3..5f3386844134 100644
--- a/include/linux/ceph/auth.h
+++ b/include/linux/ceph/auth.h
@@ -78,6 +78,8 @@ struct ceph_auth_client {
         u64 global_id;          /* our unique id in system */
         const struct ceph_crypto_key *key;     /* our secret key */
         unsigned want_keys;     /* which services we want */
+
+        struct mutex mutex;
 };
 
 extern struct ceph_auth_client *ceph_auth_init(const char *name,
diff --git a/net/ceph/auth.c b/net/ceph/auth.c
index a22de543cedb..6b923bcaa2a4 100644
--- a/net/ceph/auth.c
+++ b/net/ceph/auth.c
@@ -47,6 +47,7 @@ struct ceph_auth_client *ceph_auth_init(const char *name, const struct ceph_cryp
         if (!ac)
                 goto out;
 
+        mutex_init(&ac->mutex);
         ac->negotiating = true;
         if (name)
                 ac->name = name;
@@ -73,10 +74,12 @@ void ceph_auth_destroy(struct ceph_auth_client *ac)
  */
 void ceph_auth_reset(struct ceph_auth_client *ac)
 {
+        mutex_lock(&ac->mutex);
         dout("auth_reset %p\n", ac);
         if (ac->ops && !ac->negotiating)
                 ac->ops->reset(ac);
         ac->negotiating = true;
+        mutex_unlock(&ac->mutex);
 }
 
 int ceph_entity_name_encode(const char *name, void **p, void *end)
@@ -102,6 +105,7 @@ int ceph_auth_build_hello(struct ceph_auth_client *ac, void *buf, size_t len)
         int i, num;
         int ret;
 
+        mutex_lock(&ac->mutex);
         dout("auth_build_hello\n");
         monhdr->have_version = 0;
         monhdr->session_mon = cpu_to_le16(-1);
@@ -122,15 +126,19 @@ int ceph_auth_build_hello(struct ceph_auth_client *ac, void *buf, size_t len)
 
         ret = ceph_entity_name_encode(ac->name, &p, end);
         if (ret < 0)
-                return ret;
+                goto out;
         ceph_decode_need(&p, end, sizeof(u64), bad);
         ceph_encode_64(&p, ac->global_id);
 
         ceph_encode_32(&lenp, p - lenp - sizeof(u32));
-        return p - buf;
+        ret = p - buf;
+out:
+        mutex_unlock(&ac->mutex);
+        return ret;
 
 bad:
-        return -ERANGE;
+        ret = -ERANGE;
+        goto out;
 }
 
 static int ceph_build_auth_request(struct ceph_auth_client *ac,
@@ -151,11 +159,13 @@ static int ceph_build_auth_request(struct ceph_auth_client *ac,
         if (ret < 0) {
                 pr_err("error %d building auth method %s request\n", ret,
                        ac->ops->name);
-                return ret;
+                goto out;
         }
         dout(" built request %d bytes\n", ret);
         ceph_encode_32(&p, ret);
-        return p + ret - msg_buf;
+        ret = p + ret - msg_buf;
+out:
+        return ret;
 }
 
 /*
@@ -176,6 +186,7 @@ int ceph_handle_auth_reply(struct ceph_auth_client *ac,
         int result_msg_len;
         int ret = -EINVAL;
 
+        mutex_lock(&ac->mutex);
         dout("handle_auth_reply %p %p\n", p, end);
         ceph_decode_need(&p, end, sizeof(u32) * 3 + sizeof(u64), bad);
         protocol = ceph_decode_32(&p);
@@ -227,35 +238,44 @@ int ceph_handle_auth_reply(struct ceph_auth_client *ac,
 
         ret = ac->ops->handle_reply(ac, result, payload, payload_end);
         if (ret == -EAGAIN) {
-                return ceph_build_auth_request(ac, reply_buf, reply_len);
+                ret = ceph_build_auth_request(ac, reply_buf, reply_len);
         } else if (ret) {
                 pr_err("auth method '%s' error %d\n", ac->ops->name, ret);
-                return ret;
         }
-        return 0;
 
-bad:
-        pr_err("failed to decode auth msg\n");
 out:
+        mutex_unlock(&ac->mutex);
         return ret;
+
+bad:
+        pr_err("failed to decode auth msg\n");
+        ret = -EINVAL;
+        goto out;
 }
 
 int ceph_build_auth(struct ceph_auth_client *ac,
                     void *msg_buf, size_t msg_len)
 {
+        int ret = 0;
+
+        mutex_lock(&ac->mutex);
         if (!ac->protocol)
-                return ceph_auth_build_hello(ac, msg_buf, msg_len);
-        BUG_ON(!ac->ops);
-        if (ac->ops->should_authenticate(ac))
-                return ceph_build_auth_request(ac, msg_buf, msg_len);
-        return 0;
+                ret = ceph_auth_build_hello(ac, msg_buf, msg_len);
+        else if (ac->ops->should_authenticate(ac))
+                ret = ceph_build_auth_request(ac, msg_buf, msg_len);
+        mutex_unlock(&ac->mutex);
+        return ret;
 }
 
 int ceph_auth_is_authenticated(struct ceph_auth_client *ac)
 {
-        if (!ac->ops)
-                return 0;
-        return ac->ops->is_authenticated(ac);
+        int ret = 0;
+
+        mutex_lock(&ac->mutex);
+        if (ac->ops)
+                ret = ac->ops->is_authenticated(ac);
+        mutex_unlock(&ac->mutex);
+        return ret;
 }
 EXPORT_SYMBOL(ceph_auth_is_authenticated);
 
@@ -263,17 +283,23 @@ int ceph_auth_create_authorizer(struct ceph_auth_client *ac,
                                 int peer_type,
                                 struct ceph_auth_handshake *auth)
 {
+        int ret = 0;
+
+        mutex_lock(&ac->mutex);
         if (ac->ops && ac->ops->create_authorizer)
-                return ac->ops->create_authorizer(ac, peer_type, auth);
-        return 0;
+                ret = ac->ops->create_authorizer(ac, peer_type, auth);
+        mutex_unlock(&ac->mutex);
+        return ret;
 }
 EXPORT_SYMBOL(ceph_auth_create_authorizer);
 
 void ceph_auth_destroy_authorizer(struct ceph_auth_client *ac,
                                   struct ceph_authorizer *a)