Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.11 260/775] Drivers: hv: vmbus: Avoid use-after-free in vmbus_onoffer_rescind() | Date | Mon, 1 Mar 2021 17:07:08 +0100 |
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From: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
[ Upstream commit e3fa4b747f085d2cda09bba0533b86fa76038635 ]
When channel->device_obj is non-NULL, vmbus_onoffer_rescind() could invoke put_device(), that will eventually release the device and free the channel object (cf. vmbus_device_release()). However, a pointer to the object is dereferenced again later to load the primary_channel. The use-after-free can be avoided by noticing that this load/check is redundant if device_obj is non-NULL: primary_channel must be NULL if device_obj is non-NULL, cf. vmbus_add_channel_work().
Fixes: 54a66265d6754b ("Drivers: hv: vmbus: Fix rescind handling") Reported-by: Juan Vazquez <juvazq@microsoft.com> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20201209070827.29335-5-parri.andrea@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/hv/channel_mgmt.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 1d44bb635bb84..6be9f56cb6270 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -1102,8 +1102,7 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr) vmbus_device_unregister(channel->device_obj); put_device(dev); } - } - if (channel->primary_channel != NULL) { + } else if (channel->primary_channel != NULL) { /* * Sub-channel is being rescinded. Following is the channel * close sequence when initiated from the driveri (refer to -- 2.27.0
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