kernel/linux.git/net/mctp, branch v5.15.210

net: mctp: fix don't require received header reserved bits to be zero

2026-06-19T11:33:41+00:00

[ Upstream commit a663bac71a2f0b3ac6c373168ca57b2a6e6381aa ] >From the MCTP Base specification (DSP0236 v1.2.1), the first byte of the MCTP header contains a 4 bit reserved field, and 4 bit version. On our current receive path, we require those 4 reserved bits to be zero, but the 9500-8i card is non-conformant, and may set these reserved bits. DSP0236 states that the reserved bits must be written as zero, and ignored when read. While the device might not conform to the former, we should accept these message to conform to the latter. Relax our check on the MCTP version byte to allow non-zero bits in the reserved field. Fixes: 889b7da23abf ("mctp: Add initial routing framework") Signed-off-by: Yuan Zhaoming Cc: stable@vger.kernel.org Acked-by: Jeremy Kerr Link: https://patch.msgid.link/20260417141340.5306-1-yuanzhaoming901030@126.com Signed-off-by: Jakub Kicinski [ Context ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: mctp: ensure our nlmsg responses are initialised

2026-06-19T11:33:22+00:00

[ Upstream commit a6a9bc544b675d8b5180f2718ec985ad267b5cbf ] Syed Faraz Abrar (@farazsth98) from Zellic, and Pumpkin (@u1f383) from DEVCORE Research Team working with Trend Micro Zero Day Initiative report that a RTM_GETNEIGH will return uninitalised data in the pad bytes of the ndmsg data. Ensure we're initialising the netlink data to zero, in the link, addr and neigh response messages. Fixes: 831119f88781 ("mctp: Add neighbour netlink interface") Fixes: 06d2f4c583a7 ("mctp: Add netlink route management") Fixes: 583be982d934 ("mctp: Add device handling and netlink interface") Signed-off-by: Jeremy Kerr Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260209-dev-mctp-nlmsg-v1-1-f1e30c346a43@codeconstruct.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Sasha Levin

net: mctp: Don't access ifa_index when missing

2026-04-18T08:33:35+00:00

[ Upstream commit f11cf946c0a92c560a890d68e4775723353599e1 ] In mctp_dump_addrinfo, ifa_index can be used to filter interfaces, but only when the struct ifaddrmsg is provided. Otherwise it will be comparing to uninitialised memory - reproducible in the syzkaller case from dhcpd, or busybox "ip addr show". The kernel MCTP implementation has always filtered by ifa_index, so existing userspace programs expecting to dump MCTP addresses must already be passing a valid ifa_index value (either 0 or a real index). BUG: KMSAN: uninit-value in mctp_dump_addrinfo+0x208/0xac0 net/mctp/device.c:128 mctp_dump_addrinfo+0x208/0xac0 net/mctp/device.c:128 rtnl_dump_all+0x3ec/0x5b0 net/core/rtnetlink.c:4380 rtnl_dumpit+0xd5/0x2f0 net/core/rtnetlink.c:6824 netlink_dump+0x97b/0x1690 net/netlink/af_netlink.c:2309 [ The context change is due to the commit 2d45eeb7d5d7 ("mctp: no longer rely on net->dev_index_head[]") in v6.14 which is irrelevant to the logic of this patch. ] Fixes: 583be982d934 ("mctp: Add device handling and netlink interface") Reported-by: syzbot+e76d52dadc089b9d197f@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68135815.050a0220.3a872c.000e.GAE@google.com/ Reported-by: syzbot+1065a199625a388fce60@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/681357d6.050a0220.14dd7d.000d.GAE@google.com/ Signed-off-by: Matt Johnston Link: https://patch.msgid.link/20250508-mctp-addr-dump-v2-1-c8a53fd2dd66@codeconstruct.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Johnny Hao Signed-off-by: Sasha Levin

net: mctp: Prevent duplicate binds

2025-08-28T14:24:20+00:00

[ Upstream commit 3954502377ec05a1b37e2dc9bef0bacd4bbd71b2 ] Disallow bind() calls that have the same arguments as existing bound sockets. Previously multiple sockets could bind() to the same type/local address, with an arbitrary socket receiving matched messages. This is only a partial fix, a future commit will define precedence order for MCTP_ADDR_ANY versus specific EID bind(), which are allowed to exist together. Signed-off-by: Matt Johnston Link: https://patch.msgid.link/20250710-mctp-bind-v4-2-8ec2f6460c56@codeconstruct.com.au Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: mctp: Set SOCK_RCU_FREE

2025-05-02T05:44:10+00:00

[ Upstream commit 52024cd6ec71a6ca934d0cc12452bd8d49850679 ] Bind lookup runs under RCU, so ensure that a socket doesn't go away in the middle of a lookup. Fixes: 833ef3b91de6 ("mctp: Populate socket implementation") Signed-off-by: Matt Johnston Link: https://patch.msgid.link/20250410-mctp-rcu-sock-v1-1-872de9fdc877@codeconstruct.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mctp: Handle error of rtnl_register_module().

2024-10-17T13:11:57+00:00

[ Upstream commit d51705614f668254cc5def7490df76f9680b4659 ] Since introduced, mctp has been ignoring the returned value of rtnl_register_module(), which could fail silently. Handling the error allows users to view a module as an all-or-nothing thing in terms of the rtnetlink functionality. This prevents syzkaller from reporting spurious errors from its tests, where OOM often occurs and module is automatically loaded. Let's handle the errors by rtnl_register_many(). Fixes: 583be982d934 ("mctp: Add device handling and netlink interface") Fixes: 831119f88781 ("mctp: Add neighbour netlink interface") Fixes: 06d2f4c583a7 ("mctp: Add netlink route management") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jeremy Kerr Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

mctp: perform route lookups under a RCU read-side lock

2023-10-25T09:58:59+00:00

[ Upstream commit 5093bbfc10ab6636b32728e35813cbd79feb063c ] Our current route lookups (mctp_route_lookup and mctp_route_lookup_null) traverse the net's route list without the RCU read lock held. This means the route lookup is subject to preemption, resulting in an potential grace period expiry, and so an eventual kfree() while we still have the route pointer. Add the proper read-side critical section locks around the route lookups, preventing premption and a possible parallel kfree. The remaining net->mctp.routes accesses are already under a rcu_read_lock, or protected by the RTNL for updates. Based on an analysis from Sili Luo , where introducing a delay in the route lookup could cause a UAF on simultaneous sendmsg() and route deletion. Reported-by: Sili Luo Fixes: 889b7da23abf ("mctp: Add initial routing framework") Cc: stable@vger.kernel.org Signed-off-by: Jeremy Kerr Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/29c4b0e67dc1bf3571df3982de87df90cae9b631.1696837310.git.jk@codeconstruct.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mctp: Allow local delivery to the null EID

2023-10-25T09:58:59+00:00

[ Upstream commit 1f6c77ac9e6ecef152fd5df94c4b3c346adb197a ] We may need to receive packets addressed to the null EID (==0), but addressed to us at the physical layer. This change adds a lookup for local routes when we see a packet addressed to EID 0, and a local phys address. Signed-off-by: Jeremy Kerr Signed-off-by: David S. Miller Stable-dep-of: 5093bbfc10ab ("mctp: perform route lookups under a RCU read-side lock") Signed-off-by: Sasha Levin

net: mctp: purge receive queues on sk destruction

2023-02-06T06:59:02+00:00

commit 60bd1d9008a50cc78c4033a16a6f5d78210d481c upstream. We may have pending skbs in the receive queue when the sk is being destroyed; add a destructor to purge the queue. MCTP doesn't use the error queue, so only the receive_queue is purged. Fixes: 833ef3b91de6 ("mctp: Populate socket implementation") Signed-off-by: Jeremy Kerr Reviewed-by: Pavan Chebbi Link: https://lore.kernel.org/r/20230126064551.464468-1-jk@codeconstruct.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: mctp: mark socks as dead on unhash, prevent re-add

2023-02-01T07:27:28+00:00

[ Upstream commit b98e1a04e27fddfdc808bf46fe78eca30db89ab3 ] Once a socket has been unhashed, we want to prevent it from being re-used in a sk_key entry as part of a routing operation. This change marks the sk as SOCK_DEAD on unhash, which prevents addition into the net's key list. We need to do this during the key add path, rather than key lookup, as we release the net keys_lock between those operations. Fixes: 4a992bbd3650 ("mctp: Implement message fragmentation & reassembly") Signed-off-by: Jeremy Kerr Signed-off-by: David S. Miller Signed-off-by: Sasha Levin