Commit 956db0a1 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

net: warn about attempts to register negative ifindex 



Since the xarray changes we mix returning valid ifindex and negative
errno in a single int returned from dev_index_reserve(). This depends
on the fact that ifindexes can't be negative. Otherwise we may insert
into the xarray and return a very large negative value. This in turn
may break ERR_PTR().

OvS is susceptible to this problem and lacking validation (fix posted
separately for net).

Reject negative ifindex explicitly. Add a warning because the input
validation is better handled by the caller.

Reviewed-by: default avatarLeon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20230814205627.2914583-2-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent cf74eb5a

net/core/dev.c

+5 −0
Original line number Diff line number Diff line
@@ -9589,6 +9589,11 @@ static int dev_index_reserve(struct net *net, u32 ifindex) 
{

	int err;



	if (ifindex > INT_MAX) {

		DEBUG_NET_WARN_ON_ONCE(1);

		return -EINVAL;

	}



	if (!ifindex)

		err = xa_alloc_cyclic(&net->dev_by_index, &ifindex, NULL,

				      xa_limit_31b, &net->ifindex, GFP_KERNEL);