title: tipc: Check the bearer type before calling tipc_udp_nl_bearer_add()
description: In the Linux kernel, the following vulnerability has been resolved:
tipc: Check the bearer type before calling tipc_udp_nl_bearer_add()
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().
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: ef20cd4dd163, lessThan: 24ec8f0da93b, status: affected, versionType: git
version: ef20cd4dd163, lessThan: 6f70f0b41245, status: affected, versionType: git
version: ef20cd4dd163, lessThan: 19d7314f2fb9, status: affected, versionType: git
version: ef20cd4dd163, lessThan: c1701ea85ef0, status: affected, versionType: git
version: ef20cd4dd163, lessThan: 3d3a5b31b435, status: affected, versionType: git
version: ef20cd4dd163, lessThan: 888e3524be87, status: affected, versionType: git
version: ef20cd4dd163, lessThan: 0cd331dfd602, status: affected, versionType: git
version: ef20cd4dd163, lessThan: 3871aa01e1a7, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 4.9, status: affected
version: 0, lessThan: 4.9, status: unaffected, versionType: custom
version: 4.19.307, lessThanOrEqual: 4.19.*, status: unaffected, versionType: custom
version: 5.4.269, lessThanOrEqual: 5.4.*, status: unaffected, versionType: custom
version: 5.10.210, lessThanOrEqual: 5.10.*, status: unaffected, versionType: custom
version: 5.15.149, lessThanOrEqual: 5.15.*, status: unaffected, versionType: custom
version: 6.1.78, lessThanOrEqual: 6.1.*, status: unaffected, versionType: custom
version: 6.6.17, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.5, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
