net: mctp: ensure our nlmsg responses are initialised

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 <jk@codeconstruct.com.au>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260209-dev-mctp-nlmsg-v1-1-f1e30c346a43@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mctp/device.c b/net/mctp/device.c
index 4d404edd7446e187dd3aa18ee2086c4e2e3da3ee..04c5570bacff69690456d73490a9e4bdebf49d8d 100644 (file)
--- a/net/mctp/device.c
+++ b/net/mctp/device.c
@@ -70,6 +70,7 @@ static int mctp_fill_addrinfo(struct sk_buff *skb,
                return -EMSGSIZE;
 
        hdr = nlmsg_data(nlh);
+       memset(hdr, 0, sizeof(*hdr));
        hdr->ifa_family = AF_MCTP;
        hdr->ifa_prefixlen = 0;
        hdr->ifa_flags = 0;

diff --git a/net/mctp/neigh.c b/net/mctp/neigh.c
index 05b899f22d902b275ca1e300542a8d546d59ea15..fc85f0e693014309da9c60e46485466cb5bb6dda 100644 (file)
--- a/net/mctp/neigh.c
+++ b/net/mctp/neigh.c
@@ -218,6 +218,7 @@ static int mctp_fill_neigh(struct sk_buff *skb, u32 portid, u32 seq, int event,
                return -EMSGSIZE;
 
        hdr = nlmsg_data(nlh);
+       memset(hdr, 0, sizeof(*hdr));
        hdr->ndm_family = AF_MCTP;
        hdr->ndm_ifindex = dev->ifindex;
        hdr->ndm_state = 0; // TODO other state bits?

diff --git a/net/mctp/route.c b/net/mctp/route.c
index 2ac4011a953fffe9e01f3bfe0f571b3727b3e903..ecbbe4beb2133b90d2a02031baaa058644f0e8fe 100644 (file)
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -1643,6 +1643,7 @@ static int mctp_fill_rtinfo(struct sk_buff *skb, struct mctp_route *rt,
                return -EMSGSIZE;
 
        hdr = nlmsg_data(nlh);
+       memset(hdr, 0, sizeof(*hdr));
        hdr->rtm_family = AF_MCTP;
 
        /* we use the _len fields as a number of EIDs, rather than