On Tue, May 29, 2018 at 05:35:25PM -0700, Kees Cook wrote: > In the quest to remove all stack VLA usage from the kernel[1], this > allocates the maximum size expected for all possible attrs and adds > a sanity-check to make sure nothing gets out of sync. > > [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > net/netfilter/nfnetlink.c | 22 ++++++++++++++++++++-- > 1 file changed, 20 insertions(+), 2 deletions(-) > > diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c > index 03ead8a9e90c..0cb395f9627e 100644 > --- a/net/netfilter/nfnetlink.c > +++ b/net/netfilter/nfnetlink.c > @@ -28,6 +28,7 @@ > > #include <net/netlink.h> > #include <linux/netfilter/nfnetlink.h> > +#include <linux/netfilter/nf_tables.h> > > MODULE_LICENSE("GPL"); > MODULE_AUTHOR("Harald Welte <laforge@xxxxxxxxxxxxx>"); > @@ -37,6 +38,11 @@ MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); > rcu_dereference_protected(table[(id)].subsys, \ > lockdep_nfnl_is_held((id))) > > +#define NFTA_MAX_ATTR max(max(max(NFTA_CHAIN_MAX, NFTA_FLOWTABLE_MAX),\ > + max(NFTA_OBJ_MAX, NFTA_RULE_MAX)), \ > + max(NFTA_TABLE_MAX, \ > + max(NFTA_SET_ELEM_LIST_MAX, NFTA_SET_MAX))) This is very specific of nftables, there are other nf subsystems using nfnetlink that may go over this maximum attribute value (grep from "struct nfnetlink_subsystem"). To remove the VLA, I think we need an artificial maximum attribute that reasonably large enough. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
