rtnetlink: let rtnl_bridge_setlink checks IFLA_BRIDGE_MODE length
[ Upstream commit d73ef2d69c0dba5f5a1cb9600045c873bab1fb7f ] There are totally 9 ndo_bridge_setlink handlers in the current kernel, which are 1) bnxt_bridge_setlink, 2) be_ndo_bridge_setlink 3) i40e_ndo_bridge_setlink 4) ice_bridge_setlink 5) ixgbe_ndo_bridge_setlink 6) mlx5e_bridge_setlink 7) nfp_net_bridge_setlink 8) qeth_l2_bridge_setlink 9) br_setlink. By investigating the code, we find that 1-7 parse and use nlattr IFLA_BRIDGE_MODE but 3 and 4 forget to do the nla_len check. 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. To avoid such issues, also for other ndo_bridge_setlink handlers in the future. This patch adds the nla_len check in rtnl_bridge_setlink and does an early error return if length mismatches. To make it works, the break is removed from the parsing for IFLA_BRIDGE_FLAGS to make sure this nla_for_each_nested iterates every attribute. Fixes:b1edc14a3f
("ice: Implement ice_bridge_getlink and ice_bridge_setlink") Fixes:51616018dd
("i40e: Add support for getlink, setlink ndo ops") Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Lin Ma <linma@zju.edu.cn> Acked-by: Nikolay Aleksandrov <razor@blackwall.org> Reviewed-by: Hangbin Liu <liuhangbin@gmail.com> Link: https://lore.kernel.org/r/20230726075314.1059224-1-linma@zju.edu.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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@ -4590,13 +4590,17 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
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br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC);
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if (br_spec) {
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nla_for_each_nested(attr, br_spec, rem) {
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if (nla_type(attr) == IFLA_BRIDGE_FLAGS) {
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if (nla_type(attr) == IFLA_BRIDGE_FLAGS && !have_flags) {
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if (nla_len(attr) < sizeof(flags))
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return -EINVAL;
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have_flags = true;
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flags = nla_get_u16(attr);
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break;
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}
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if (nla_type(attr) == IFLA_BRIDGE_MODE) {
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if (nla_len(attr) < sizeof(u16))
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return -EINVAL;
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}
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}
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}
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