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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>,
        Saruhan Karademir <skarade@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Wei Liu <wei.liu@kernel.org>, Sasha Levin <sashal@kernel.org>,
        linux-hyperv@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 069/130] hv_netvsc: Validate number of allocated sub-channels
Date:   Tue, 22 Dec 2020 21:17:12 -0500
Message-Id: <20201223021813.2791612-69-sashal@kernel.org>
In-Reply-To: <20201223021813.2791612-1-sashal@kernel.org>
References: <20201223021813.2791612-1-sashal@kernel.org>
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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 b9e44bb22289c..90d81dc6a1221 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1159,6 +1159,11 @@ int rndis_set_subchannel(struct net_device *ndev,
 		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