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

Yan Zhao
2023-02-22T08:13:48Z

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@intel.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