2008-04-19 20:50:30

by Myklebust, Trond

[permalink] [raw]
Subject: [PATCH 29/33] 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: Trond Myklebust <[email protected]>
---

net/sunrpc/auth_gss/auth_gss.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 46f7ec8..6f1b4e2 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -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);