| Message ID | 20230725022151.417450-1-linma@zju.edu.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v1] rtnetlink: let rtnl_bridge_setlink checks IFLA_BRIDGE_MODE length | expand |
On Tue, Jul 25, 2023 at 10:21:51AM +0800, Lin Ma wrote: > 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. > > Fixes: b1edc14a3fbf ("ice: Implement ice_bridge_getlink and ice_bridge_setlink") > Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops") > Suggested-by: Jakub Kicinski <kuba@kernel.org> > Signed-off-by: Lin Ma <linma@zju.edu.cn> > --- > net/core/rtnetlink.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 3ad4e030846d..1e51291007ea 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -5148,6 +5148,11 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, > flags = nla_get_u16(attr); > break; > } If we got attr tIFLA_BRIDGE_FLAGS first, it will break here and not check the later IFLA_BRIDGE_MODE. > + > + if (nla_type(attr) == IFLA_BRIDGE_MODE) { > + if (nla_len(attr) < sizeof(u16)) > + return -EINVAL; > + } > } > } Thanks Hangbin
Hello Hangbin, > > If we got attr tIFLA_BRIDGE_FLAGS first, it will break here and not check > the later IFLA_BRIDGE_MODE. > > > + > > + if (nla_type(attr) == IFLA_BRIDGE_MODE) { > > + if (nla_len(attr) < sizeof(u16)) > > + return -EINVAL; > > + } > > } > > } > > Thanks > Hangbin Yeah, you are soooo right, will fix this ASAP Regards Lin
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 3ad4e030846d..1e51291007ea 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -5148,6 +5148,11 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, flags = nla_get_u16(attr); break; } + + if (nla_type(attr) == IFLA_BRIDGE_MODE) { + if (nla_len(attr) < sizeof(u16)) + return -EINVAL; + } } }
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. Fixes: b1edc14a3fbf ("ice: Implement ice_bridge_getlink and ice_bridge_setlink") Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops") Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Lin Ma <linma@zju.edu.cn> --- net/core/rtnetlink.c | 5 +++++ 1 file changed, 5 insertions(+)