SUNRPC: Ensure that gss_auth isn't freed before its upcall messages
Fix a race in which the RPC client is shutting down while the
gss daemon is processing a downcall. If the RPC client manages to
shut down before the gss daemon is done, then the struct gss_auth
used in gss_release_msg() may have already been freed.
Link: http://lkml.kernel.org/r/[email protected]
Reported-by: John <[email protected]>
Reported-by: Borislav Petkov <[email protected]>
Cc: [email protected] # 3.12+
Signed-off-by: Trond Myklebust <[email protected]>
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 44a61e8..1ba1fd1 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -108,6 +108,7 @@
static DEFINE_SPINLOCK(pipe_version_lock);
static struct rpc_wait_queue pipe_version_rpc_waitqueue;
static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue);
+static void gss_put_auth(struct gss_auth *gss_auth);
static void gss_free_ctx(struct gss_cl_ctx *);
static const struct rpc_pipe_ops gss_upcall_ops_v0;
@@ -320,6 +321,7 @@
if (gss_msg->ctx != NULL)
gss_put_ctx(gss_msg->ctx);
rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue);
+ gss_put_auth(gss_msg->auth);
kfree(gss_msg);
}
@@ -500,6 +502,7 @@
if (err)
goto err_free_msg;
};
+ kref_get(&gss_auth->kref);
return gss_msg;
err_free_msg:
kfree(gss_msg);
@@ -1064,6 +1067,12 @@
}
static void
+gss_put_auth(struct gss_auth *gss_auth)
+{
+ kref_put(&gss_auth->kref, gss_free_callback);
+}
+
+static void
gss_destroy(struct rpc_auth *auth)
{
struct gss_auth *gss_auth = container_of(auth,
@@ -1084,7 +1093,7 @@
gss_auth->gss_pipe[1] = NULL;
rpcauth_destroy_credcache(auth);
- kref_put(&gss_auth->kref, gss_free_callback);
+ gss_put_auth(gss_auth);
}
/*
@@ -1255,7 +1264,7 @@
call_rcu(&cred->cr_rcu, gss_free_cred_callback);
if (ctx)
gss_put_ctx(ctx);
- kref_put(&gss_auth->kref, gss_free_callback);
+ gss_put_auth(gss_auth);
}
static void
