diff mbox series

[net,3/3] netfilter: ipset: Fix race between IPSET_CMD_CREATE and IPSET_CMD_SWAP

Message ID 20230920084156.4192-4-fw@strlen.de (mailing list archive)
State Accepted
Commit 7433b6d2afd512d04398c73aa984d1e285be125b
Delegated to: Netdev Maintainers
Headers show
Series [net,1/3] netfilter: nf_tables: disable toggling dormant table state more than once | expand

Checks

Context Check Description
netdev/series_format success Pull request is its own cover letter
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1345 this patch: 1345
netdev/cc_maintainers fail 2 blamed authors not CCed: kuniyu@amazon.com pablo@netfilter.org; 4 maintainers not CCed: kuniyu@amazon.com justinstitt@google.com pablo@netfilter.org coreteam@netfilter.org
netdev/build_clang success Errors and warnings before: 1363 this patch: 1363
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1368 this patch: 1368
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 27 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Florian Westphal Sept. 20, 2023, 8:41 a.m. UTC 
From: Jozsef Kadlecsik <kadlec@netfilter.org>

Kyle Zeng reported that there is a race between IPSET_CMD_ADD and IPSET_CMD_SWAP
in netfilter/ip_set, which can lead to the invocation of `__ip_set_put` on a
wrong `set`, triggering the `BUG_ON(set->ref == 0);` check in it.

The race is caused by using the wrong reference counter, i.e. the ref counter instead
of ref_netlink.

Fixes: 24e227896bbf ("netfilter: ipset: Add schedule point in call_ad().")
Reported-by: Kyle Zeng <zengyhkyle@gmail.com>
Closes: https://lore.kernel.org/netfilter-devel/ZPZqetxOmH+w%2Fmyc@westworld/#r
Tested-by: Kyle Zeng <zengyhkyle@gmail.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/ipset/ip_set_core.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index e564b5174261..35d2f9c9ada0 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -682,6 +682,14 @@  __ip_set_put(struct ip_set *set)
 /* set->ref can be swapped out by ip_set_swap, netlink events (like dump) need
  * a separate reference counter
  */
+static void
+__ip_set_get_netlink(struct ip_set *set)
+{
+	write_lock_bh(&ip_set_ref_lock);
+	set->ref_netlink++;
+	write_unlock_bh(&ip_set_ref_lock);
+}
+
 static void
 __ip_set_put_netlink(struct ip_set *set)
 {
@@ -1693,11 +1701,11 @@  call_ad(struct net *net, struct sock *ctnl, struct sk_buff *skb,
 
 	do {
 		if (retried) {
-			__ip_set_get(set);
+			__ip_set_get_netlink(set);
 			nfnl_unlock(NFNL_SUBSYS_IPSET);
 			cond_resched();
 			nfnl_lock(NFNL_SUBSYS_IPSET);
-			__ip_set_put(set);
+			__ip_set_put_netlink(set);
 		}
 
 		ip_set_lock(set);