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From:   Lin Ma <linma@zju.edu.cn>
To:     jesse.brandeburg@intel.com, anthony.l.nguyen@intel.com,
        davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, richardcochran@gmail.com, ast@kernel.org,
        daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com,
        intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Lin Ma <linma@zju.edu.cn>
Subject: [PATCH v1] ice: Add length check for IFLA_AF_SPEC parsing
Date:   Sun, 23 Jul 2023 15:52:39 +0800
Message-Id: <20230723075239.3710086-1-linma@zju.edu.cn>
Precedence: bulk

The nla_for_each_nested parsing in function ice_bridge_setlink() does
not check the length of the nested attribute. This can lead to an
out-of-attribute read and allow a malformed nlattr (e.g., length 0) to
be viewed as a 2 byte integer.

This patch adds the check based on nla_len() just as other code does,
see how bnxt_bridge_setlink (drivers/net/ethernet/broadcom/bnxt/bnxt.c)
parses IFLA_AF_SPEC: type checking plus length checking.

Fixes: b1edc14a3fbf ("ice: Implement ice_bridge_getlink and ice_bridge_setlink")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
 drivers/net/ethernet/intel/ice/ice_main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 19a5e7f3a075..85730075dcb4 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -7701,6 +7701,10 @@ ice_bridge_setlink(struct net_device *dev, struct nlmsghdr *nlh,
 
 		if (nla_type(attr) != IFLA_BRIDGE_MODE)
 			continue;
+
+		if (nla_len(attr) < sizeof(mode))
+			return -EINVAL;
+
 		mode = nla_get_u16(attr);
 		if (mode != BRIDGE_MODE_VEPA && mode != BRIDGE_MODE_VEB)
 			return -EINVAL;
-- 
2.17.1