6.12-stable review patch. If anyone has any objections, please let me know.
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From: Haixia Qu hxqu@hillstonenet.com
[ 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 --- 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 108a4cc2e0010..258d6aa4f21ae 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; }