From: Xingyuan Mo <hdthky0@gmail.com>
Date: Thu, 12 Jan 2023 00:24:53 +0800
Subject: [PATCH] NFSD: fix use-after-free in nfsd4_ssc_setup_dul()
Git-commit: e6cf91b7b47ff82b624bdfe2fdcde32bb52e71dd
Patch-mainline: v6.2
References: git-fixes bsc#1209788 CVE-2023-1652

If signal_pending() returns true, schedule_timeout() will not be executed,
causing the waiting task to remain in the wait queue.
Fixed by adding a call to finish_wait(), which ensures that the waiting
task will always be removed from the wait queue.

Fixes: f4e44b393389 ("NFSD: delay unmount source's export after inter-server copy completed.")
Signed-off-by: Xingyuan Mo <hdthky0@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfsd/nfs4proc.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1205,6 +1205,7 @@ try_again:
 			/* allow 20secs for mount/unmount for now - revisit */
 			if (signal_pending(current) ||
 					(schedule_timeout(20*HZ) == 0)) {
+				finish_wait(&nn->nfsd_ssc_waitq, &wait);
 				kfree(work);
 				return nfserr_eagain;
 			}