linux-kernel - [PATCH] vfio: Fix NULL pointer dereference caused by uninitialized group->iommufd

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Message-Id: <20230222074938.13681-1-yan.y.zhao@intel.com>
Date:   Wed, 22 Feb 2023 15:49:38 +0800
From:   Yan Zhao <yan.y.zhao@...el.com>
To:     alex.williamson@...hat.com, jgg@...dia.com, kevin.tian@...el.com
Cc:     yi.l.liu@...el.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Yan Zhao <yan.y.zhao@...el.com>
Subject: [PATCH] vfio: Fix NULL pointer dereference caused by uninitialized group->iommufd

group->iommufd is not initialized for the iommufd_ctx_put()

[20018.331541] BUG: kernel NULL pointer dereference, address: 0000000000000000
[20018.377508] RIP: 0010:iommufd_ctx_put+0x5/0x10 [iommufd]
...
[20018.476483] Call Trace:
[20018.479214]  <TASK>
[20018.481555]  vfio_group_fops_unl_ioctl+0x506/0x690 [vfio]
[20018.487586]  __x64_sys_ioctl+0x6a/0xb0
[20018.491773]  ? trace_hardirqs_on+0xc5/0xe0
[20018.496347]  do_syscall_64+0x67/0x90
[20018.500340]  entry_SYSCALL_64_after_hwframe+0x4b/0xb5

Fixes: 9eefba8002c2 ("vfio: Move vfio group specific code into group.c")
Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
---
 drivers/vfio/group.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
index 57ebe5e1a7e6..8649f85f3be4 100644
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -137,7 +137,7 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group,
 
 		ret = iommufd_vfio_compat_ioas_id(iommufd, &ioas_id);
 		if (ret) {
-			iommufd_ctx_put(group->iommufd);
+			iommufd_ctx_put(iommufd);
 			goto out_unlock;
 		}
 
-- 
2.17.1