This is a note to let you know that I've just added the patch titled
tipc: Check the bearer type before calling tipc_udp_nl_bearer_add()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tipc-check-the-bearer-type-before-calling-tipc_udp_n.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8b4d0d379d64185bfc9d8481bf38a5becedfa226
Author: Shigeru Yoshida <syoshida@xxxxxxxxxx>
Date: Thu Feb 1 00:23:09 2024 +0900
tipc: Check the bearer type before calling tipc_udp_nl_bearer_add()
[ 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=5142b87a9abc510e14fa [1]
Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>
Reviewed-by: Tung Nguyen <tung.q.nguyen@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240131152310.4089541-1-syoshida@xxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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) {
