From ccf8dbcd062a930e64741c939ca784d15316aa0c Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 30 May 2018 15:20:52 -0700 Subject: rtnetlink: Remove VLA usage In the quest to remove all stack VLA usage from the kernel[1], this allocates the maximum size expected for all possible types and adds sanity-checks at both registration and usage to make sure nothing gets out of sync. This matches the proposed VLA solution for nfnetlink[2]. The values chosen here were based on finding assignments for .maxtype and .slave_maxtype and manually counting the enums: slave_maxtype (max 33): IFLA_BRPORT_MAX 33 IFLA_BOND_SLAVE_MAX 9 maxtype (max 45): IFLA_BOND_MAX 28 IFLA_BR_MAX 45 __IFLA_CAIF_HSI_MAX 8 IFLA_CAIF_MAX 4 IFLA_CAN_MAX 16 IFLA_GENEVE_MAX 12 IFLA_GRE_MAX 25 IFLA_GTP_MAX 5 IFLA_HSR_MAX 7 IFLA_IPOIB_MAX 4 IFLA_IPTUN_MAX 21 IFLA_IPVLAN_MAX 3 IFLA_MACSEC_MAX 15 IFLA_MACVLAN_MAX 7 IFLA_PPP_MAX 2 __IFLA_RMNET_MAX 4 IFLA_VLAN_MAX 6 IFLA_VRF_MAX 2 IFLA_VTI_MAX 7 IFLA_VXLAN_MAX 28 VETH_INFO_MAX 2 VXCAN_INFO_MAX 2 This additionally changes maxtype and slave_maxtype fields to unsigned, since they're only ever using positive values. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com [2] https://patchwork.kernel.org/patch/10439647/ Signed-off-by: Kees Cook Signed-off-by: David S. Miller --- include/net/rtnetlink.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/net/rtnetlink.h') diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index 14b6b3af8918..0bbaa5488423 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -64,7 +64,7 @@ struct rtnl_link_ops { size_t priv_size; void (*setup)(struct net_device *dev); - int maxtype; + unsigned int maxtype; const struct nla_policy *policy; int (*validate)(struct nlattr *tb[], struct nlattr *data[], @@ -92,7 +92,7 @@ struct rtnl_link_ops { unsigned int (*get_num_tx_queues)(void); unsigned int (*get_num_rx_queues)(void); - int slave_maxtype; + unsigned int slave_maxtype; const struct nla_policy *slave_policy; int (*slave_changelink)(struct net_device *dev, struct net_device *slave_dev, -- cgit v1.2.3-59-g8ed1b