| Message ID | 20230725055706.498774-1-linma@zju.edu.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] rtnetlink: let rtnl_bridge_setlink checks IFLA_BRIDGE_MODE length | expand |
Hi Ma Lin, Please add the target branch in your subject. e.g. [PATCHv2 net] On Tue, Jul 25, 2023 at 01:57:06PM +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. 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. Since you have checked the length in rtnl_bridge_setlink(). Can we remove the check in the driver handlers to avoid duplicate code? You can hold on this update and see if others have different opinion. Thanks Hangbin > > 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> > --- > V1 -> V2: removes the break in parsing for IFLA_BRIDGE_FLAGS suggested > by Hangbin Liu <liuhangbin@gmail.com> > > net/core/rtnetlink.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 3ad4e030846d..aef25aa5cf1d 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -5140,13 +5140,17 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, > br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC); > if (br_spec) { > nla_for_each_nested(attr, br_spec, rem) { > - if (nla_type(attr) == IFLA_BRIDGE_FLAGS) { > + if (nla_type(attr) == IFLA_BRIDGE_FLAGS && !have_flags) { > if (nla_len(attr) < sizeof(flags)) > return -EINVAL; > > have_flags = true; > flags = nla_get_u16(attr); > - break; > + } > + > + if (nla_type(attr) == IFLA_BRIDGE_MODE) { > + if (nla_len(attr) < sizeof(u16)) > + return -EINVAL; > } > } > } > -- > 2.17.1 >
On 7/25/23 08:57, 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. 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: 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> > --- > V1 -> V2: removes the break in parsing for IFLA_BRIDGE_FLAGS suggested > by Hangbin Liu <liuhangbin@gmail.com> > > net/core/rtnetlink.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 3ad4e030846d..aef25aa5cf1d 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -5140,13 +5140,17 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, > br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC); > if (br_spec) { > nla_for_each_nested(attr, br_spec, rem) { > - if (nla_type(attr) == IFLA_BRIDGE_FLAGS) { > + if (nla_type(attr) == IFLA_BRIDGE_FLAGS && !have_flags) { > if (nla_len(attr) < sizeof(flags)) > return -EINVAL; > > have_flags = true; > flags = nla_get_u16(attr); > - break; > + } > + > + if (nla_type(attr) == IFLA_BRIDGE_MODE) { > + if (nla_len(attr) < sizeof(u16)) > + return -EINVAL; > } > } > } Patch looks good now, you should probably remove the extra checks done by each driver that are now unnecessary (net-next material). As Hangbin commented you should target this fix at -net, with that: Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Hi Nikolay, > > Patch looks good now, you should probably remove the extra checks done > by each driver that are now unnecessary (net-next material). As Hangbin > commented you should target this fix at -net, with that: > > Acked-by: Nikolay Aleksandrov <razor@blackwall.org> Cool, I agree with Hangbin that another patch which removes the redundant checks in driver is needed. But I have a simple question. I will send this patch to net one and another to net-next one. How can I ensure the latter one depends on the former one? Or should I send a patch series to net-next that contains the former one :) (I currently choose the method 2 and please let me know if I do this wrong) Regards Lin
On Wed, 26 Jul 2023 15:49:02 +0800 (GMT+08:00) Lin Ma wrote: > Cool, I agree with Hangbin that another patch which removes the redundant > checks in driver is needed. > > But I have a simple question. I will send this patch to net one and another > to net-next one. How can I ensure the latter one depends on the former one? > Or should I send a patch series to net-next that contains the former one :) > (I currently choose the method 2 and please let me know if I do this wrong) You'll need to wait for the patch to propagate before posting. Our trees merge each Thursday, so if you post on Friday the fix should be in net-next.
Hi Jakub, > > You'll need to wait for the patch to propagate before posting. > Our trees merge each Thursday, so if you post on Friday the fix > should be in net-next. Cool, I understand now. Thanks! Regards Lin
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 3ad4e030846d..aef25aa5cf1d 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -5140,13 +5140,17 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC); if (br_spec) { nla_for_each_nested(attr, br_spec, rem) { - if (nla_type(attr) == IFLA_BRIDGE_FLAGS) { + if (nla_type(attr) == IFLA_BRIDGE_FLAGS && !have_flags) { if (nla_len(attr) < sizeof(flags)) return -EINVAL; have_flags = true; 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. 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: 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> --- V1 -> V2: removes the break in parsing for IFLA_BRIDGE_FLAGS suggested by Hangbin Liu <liuhangbin@gmail.com> net/core/rtnetlink.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)