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Commit 7b6962b0 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Fix a race in gss_refresh_upcall() 



If the downcall completes before we get the spin_lock then we currently
fail to refresh the credential.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 7c1d71cf

net/sunrpc/auth_gss/auth_gss.c

+8 −3
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx) 
	struct gss_cl_ctx *old;



	old = gss_cred->gc_ctx;

	gss_get_ctx(ctx);

	rcu_assign_pointer(gss_cred->gc_ctx, ctx);

	set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);

	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
@@ -340,7 +341,7 @@ gss_upcall_callback(struct rpc_task *task) 


	spin_lock(&inode->i_lock);

	if (gss_msg->ctx)

		gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_get_ctx(gss_msg->ctx));

		gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_msg->ctx);

	else

		task->tk_status = gss_msg->msg.errno;

	gss_cred->gc_upcall = NULL;
@@ -417,7 +418,11 @@ gss_refresh_upcall(struct rpc_task *task) 
	spin_lock(&inode->i_lock);

	if (gss_cred->gc_upcall != NULL)

		rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL);

	else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {

	else if (gss_msg->ctx != NULL) {

		gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_msg->ctx);

		gss_cred->gc_upcall = NULL;

		rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);

	} else if (gss_msg->msg.errno >= 0) {

		task->tk_timeout = 0;

		gss_cred->gc_upcall = gss_msg;

		/* gss_upcall_callback will release the reference to gss_upcall_msg */
@@ -462,7 +467,7 @@ gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred) 
		schedule();

	}

	if (gss_msg->ctx)

		gss_cred_set_ctx(cred, gss_get_ctx(gss_msg->ctx));

		gss_cred_set_ctx(cred, gss_msg->ctx);

	else

		err = gss_msg->msg.errno;

	spin_unlock(&inode->i_lock);