[PATCH AUTOSEL 4.14 40/66] hv_netvsc: Validate number of allocated sub-channels

* [PATCH AUTOSEL 4.14 40/66] hv_netvsc: Validate number of allocated sub-channels
       [not found] <20201223022253.2793452-1-sashal@kernel.org>
@ 2020-12-23  2:22 ` Sasha Levin
  2020-12-23  2:47   ` Michael Kelley
  0 siblings, 1 reply; 4+ messages in thread
From: Sasha Levin @ 2020-12-23  2:22 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Andrea Parri (Microsoft),
	Saruhan Karademir, Haiyang Zhang, Jakub Kicinski,
	David S. Miller, netdev, Wei Liu, Sasha Levin, linux-hyperv

From: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>

[ Upstream commit 206ad34d52a2f1205c84d08c12fc116aad0eb407 ]

Lack of validation could lead to out-of-bound reads and information
leaks (cf. usage of nvdev->chan_table[]).  Check that the number of
allocated sub-channels fits into the expected range.

Suggested-by: Saruhan Karademir <skarade@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20201118153310.112404-1-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/hyperv/rndis_filter.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index aa0bbffe49005..1db34b7a423ef 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1100,6 +1100,11 @@ int rndis_set_subchannel(struct net_device *ndev, struct netvsc_device *nvdev)
 		return -EIO;
 	}
 
+	/* Check that number of allocated sub channel is within the expected range */
+	if (init_packet->msg.v5_msg.subchn_comp.num_subchannels > nvdev->num_chn - 1) {
+		netdev_err(ndev, "invalid number of allocated sub channel\n");
+		return -EINVAL;
+	}
 	nvdev->num_chn = 1 +
 		init_packet->msg.v5_msg.subchn_comp.num_subchannels;
 
-- 
2.27.0


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