From: Saurabh Sengar ssengar@linux.microsoft.com

stable inclusion from stable-v6.6.51 commit de6946be9c8bc7d2279123433495af7c21011b99 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IARWG0 CVE: CVE-2024-46739

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit fb1adbd7e50f3d2de56d0a2bb0700e2e819a329e upstream.

For primary VM Bus channels, primary_channel pointer is always NULL. This pointer is valid only for the secondary channels. Also, rescind callback is meant for primary channels only.

Fix NULL pointer dereference by retrieving the device_obj from the parent for the primary channel.

Cc: stable@vger.kernel.org Fixes: ca3cda6fcf1e ("uio_hv_generic: add rescind support") Signed-off-by: Saurabh Sengar ssengar@linux.microsoft.com Signed-off-by: Naman Jain namjain@linux.microsoft.com Link: https://lore.kernel.org/r/20240829071312.1595-2-namjain@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Cai Xinchen caixinchen1@huawei.com --- drivers/uio/uio_hv_generic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c index 6be3462b109f..94a1fe82e4d5 100644 --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -104,10 +104,11 @@ static void hv_uio_channel_cb(void *context)

/* * Callback from vmbus_event when channel is rescinded. + * It is meant for rescind of primary channels only. */ static void hv_uio_rescind(struct vmbus_channel *channel) { - struct hv_device *hv_dev = channel->primary_channel->device_obj; + struct hv_device *hv_dev = channel->device_obj; struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);

/*