[PATCH 5.14 107/432] SUNRPC: Fix potential memory corruption

Greg Kroah-Hartman
2021-09-16T17:21:01Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit c2dc3e5fad13aca5d7bdf4bcb52b1a1d707c8555 ]

We really should not call rpc_wake_up_queued_task_set_status() with
xprt->snd_task as an argument unless we are certain that is actually an
rpc_task.

Fixes: 0445f92c5d53 ("SUNRPC: Fix disconnection races")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/sunrpc/xprt.h | 1 +
net/sunrpc/xprt.c | 6 ++++--
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index c8c39f22d3b1..59cd97da895b 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -432,6 +432,7 @@ void xprt_release_write(struct rpc_xprt *, struct rpc_task *);
#define XPRT_CONGESTED (9)
#define XPRT_CWND_WAIT (10)
#define XPRT_WRITE_SPACE (11)
+#define XPRT_SND_IS_COOKIE (12)

static inline void xprt_set_connected(struct rpc_xprt *xprt)
{
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index fb6db09725c7..bddd354a0076 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -775,9 +775,9 @@ void xprt_force_disconnect(struct rpc_xprt *xprt)
/* Try to schedule an autoclose RPC call */
if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
queue_work(xprtiod_workqueue, &xprt->task_cleanup);
- else if (xprt->snd_task)
+ else if (xprt->snd_task && !test_bit(XPRT_SND_IS_COOKIE, &xprt->state))
rpc_wake_up_queued_task_set_status(&xprt->pending,
- xprt->snd_task, -ENOTCONN);
+ xprt->snd_task, -ENOTCONN);
spin_unlock(&xprt->transport_lock);
}
EXPORT_SYMBOL_GPL(xprt_force_disconnect);
@@ -866,6 +866,7 @@ bool xprt_lock_connect(struct rpc_xprt *xprt,
goto out;
if (xprt->snd_task != task)
goto out;
+ set_bit(XPRT_SND_IS_COOKIE, &xprt->state);
xprt->snd_task = cookie;
ret = true;
out:
@@ -881,6 +882,7 @@ void xprt_unlock_connect(struct rpc_xprt *xprt, void *cookie)
if (!test_bit(XPRT_LOCKED, &xprt->state))
goto out;
xprt->snd_task =NULL;
+ clear_bit(XPRT_SND_IS_COOKIE, &xprt->state);
xprt->ops->release_xprt(xprt, NULL);
xprt_schedule_autodisconnect(xprt);
out:
--
2.30.2