4.19-stable review patch. If anyone has any objections, please let me know.
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From: Shigeru Yoshida syoshida@redhat.com
[ Upstream commit 3871aa01e1a779d866fa9dfdd5a836f342f4eb87 ]
syzbot reported the following general protection fault [1]:
general protection fault, probably for non-canonical address 0xdffffc0000000010: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000080-0x0000000000000087] ... RIP: 0010:tipc_udp_is_known_peer+0x9c/0x250 net/tipc/udp_media.c:291 ... Call Trace: <TASK> tipc_udp_nl_bearer_add+0x212/0x2f0 net/tipc/udp_media.c:646 tipc_nl_bearer_add+0x21e/0x360 net/tipc/bearer.c:1089 genl_family_rcv_msg_doit+0x1fc/0x2e0 net/netlink/genetlink.c:972 genl_family_rcv_msg net/netlink/genetlink.c:1052 [inline] genl_rcv_msg+0x561/0x800 net/netlink/genetlink.c:1067 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2544 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x53b/0x810 net/netlink/af_netlink.c:1367 netlink_sendmsg+0x8b7/0xd70 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2584 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2638 __sys_sendmsg+0x117/0x1e0 net/socket.c:2667 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b
The cause of this issue is that when tipc_nl_bearer_add() is called with the TIPC_NLA_BEARER_UDP_OPTS attribute, tipc_udp_nl_bearer_add() is called even if the bearer is not UDP.
tipc_udp_is_known_peer() called by tipc_udp_nl_bearer_add() assumes that the media_ptr field of the tipc_bearer has an udp_bearer type object, so the function goes crazy for non-UDP bearers.
This patch fixes the issue by checking the bearer type before calling tipc_udp_nl_bearer_add() in tipc_nl_bearer_add().
Fixes: ef20cd4dd163 ("tipc: introduce UDP replicast") Reported-and-tested-by: syzbot+5142b87a9abc510e14fa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5142b87a9abc510e14fa [1] Signed-off-by: Shigeru Yoshida syoshida@redhat.com Reviewed-by: Tung Nguyen tung.q.nguyen@dektech.com.au Link: https://lore.kernel.org/r/20240131152310.4089541-1-syoshida@redhat.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/tipc/bearer.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 4353968bc5a5..c7686ff00f5b 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -958,6 +958,12 @@ int tipc_nl_bearer_add(struct sk_buff *skb, struct genl_info *info)
#ifdef CONFIG_TIPC_MEDIA_UDP if (attrs[TIPC_NLA_BEARER_UDP_OPTS]) { + if (b->media->type_id != TIPC_MEDIA_TYPE_UDP) { + rtnl_unlock(); + NL_SET_ERR_MSG(info->extack, "UDP option is unsupported"); + return -EINVAL; + } + err = tipc_udp_nl_bearer_add(b, attrs[TIPC_NLA_BEARER_UDP_OPTS]); if (err) {