From: Haixia Qu <hxqu@hillstonenet.com> stable inclusion from stable-v6.6.95 commit d3dfe821dfe091c0045044343c8d86596d66e2cf category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICK4S5 CVE: CVE-2025-38184 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit f82727adcf2992822e12198792af450a76ebd5ef ] The reproduction steps: 1. create a tun interface 2. enable l2 bearer 3. TIPC_NL_UDP_GET_REMOTEIP with media name set to tun tipc: Started in network mode tipc: Node identity 8af312d38a21, cluster identity 4711 tipc: Enabled bearer <eth:syz_tun>, priority 1 Oops: general protection fault KASAN: null-ptr-deref in range CPU: 1 UID: 1000 PID: 559 Comm: poc Not tainted 6.16.0-rc1+ #117 PREEMPT Hardware name: QEMU Ubuntu 24.04 PC RIP: 0010:tipc_udp_nl_dump_remoteip+0x4a4/0x8f0 the ub was in fact a struct dev. when bid != 0 && skip_cnt != 0, bearer_list[bid] may be NULL or other media when other thread changes it. fix this by checking media_id. Fixes: 832629ca5c313 ("tipc: add UDP remoteip dump to netlink API") Signed-off-by: Haixia Qu <hxqu@hillstonenet.com> Reviewed-by: Tung Nguyen <tung.quang.nguyen@est.tech> Link: https://patch.msgid.link/20250617055624.2680-1-hxqu@hillstonenet.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Wang Liang <wangliang74@huawei.com> --- net/tipc/udp_media.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index b16ca400ff55..e993bd6ed7c2 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -489,7 +489,7 @@ int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb) rtnl_lock(); b = tipc_bearer_find(net, bname); - if (!b) { + if (!b || b->bcast_addr.media_id != TIPC_MEDIA_TYPE_UDP) { rtnl_unlock(); return -EINVAL; } @@ -500,7 +500,7 @@ int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb) rtnl_lock(); b = rtnl_dereference(tn->bearer_list[bid]); - if (!b) { + if (!b || b->bcast_addr.media_id != TIPC_MEDIA_TYPE_UDP) { rtnl_unlock(); return -EINVAL; } -- 2.33.0