Hi

Side note: This fix requires

4e7aaa6b82d6 ("netfilter: ipset: Fix race between namespace cleanup and gc in the list:set type"

in first place, as a dependency.

Thanks

On Sat, Jun 22, 2024 at 07:41:24PM -0400, Sasha Levin wrote:

This is a note to let you know that I've just added the patch titled

netfilter: ipset: Fix suspicious rcu_dereference_protected()

to the 6.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: netfilter-ipset-fix-suspicious-rcu_dereference_prote.patch and it can be found in the queue-6.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

commit 0226dfa53edc90463c1b0d50167da948c88025ef Author: Jozsef Kadlecsik kadlec@netfilter.org Date: Mon Jun 17 11:18:15 2024 +0200

netfilter: ipset: Fix suspicious rcu_dereference_protected()

[ Upstream commit 8ecd06277a7664f4ef018abae3abd3451d64e7a6 ] When destroying all sets, we are either in pernet exit phase or are executing a "destroy all sets command" from userspace. The latter was taken into account in ip_set_dereference() (nfnetlink mutex is held), but the former was not. The patch adds the required check to rcu_dereference_protected() in ip_set_dereference(). Fixes: 4e7aaa6b82d6 ("netfilter: ipset: Fix race between namespace cleanup and gc in the list:set type") Reported-by: syzbot+b62c37cdd58103293a5a@syzkaller.appspotmail.com Reported-by: syzbot+cfbe1da5fdfc39efc293@syzkaller.appspotmail.com Reported-by: kernel test robot oliver.sang@intel.com Closes: https://lore.kernel.org/oe-lkp/202406141556.e0b6f17e-lkp@intel.com Signed-off-by: Jozsef Kadlecsik kadlec@netfilter.org Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index c7ae4d9bf3d24..61431690cbd5f 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -53,12 +53,13 @@ MODULE_DESCRIPTION("core IP set support"); MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_IPSET); /* When the nfnl mutex or ip_set_ref_lock is held: */ -#define ip_set_dereference(p) \

• rcu_dereference_protected(p, \

+#define ip_set_dereference(inst) \

• rcu_dereference_protected((inst)->ip_set_list, \ lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET) || \

• lockdep_is_held(&ip_set_ref_lock))
  

• lockdep_is_held(&ip_set_ref_lock) || \
  

• (inst)->is_deleted)
  

#define ip_set(inst, id) \

• ip_set_dereference((inst)->ip_set_list)[id]

• ip_set_dereference(inst)[id]

#define ip_set_ref_netlink(inst,id) \ rcu_dereference_raw((inst)->ip_set_list)[id] #define ip_set_dereference_nfnl(p) \ @@ -1133,7 +1134,7 @@ static int ip_set_create(struct sk_buff *skb, const struct nfnl_info *info, if (!list) goto cleanup; /* nfnl mutex is held, both lists are valid */

• tmp = ip_set_dereference(inst->ip_set_list);
  

• tmp = ip_set_dereference(inst);
  

  memcpy(list, tmp, sizeof(struct ip_set *) * inst->ip_set_max); rcu_assign_pointer(inst->ip_set_list, list); /* Make sure all current packets have passed through */