From 6d745cd0e9720282cd291d36b9db528aea18add2 Mon Sep 17 00:00:00 2001
From: Petr Machata <petrm@nvidia.com>
Date: Tue, 23 Jul 2024 18:04:16 +0200
Subject: [PATCH] net: nexthop: Initialize all fields in dumped nexthops
struct nexthop_grp contains two reserved fields that are not initialized by
nla_put_nh_group(), and carry garbage. This can be observed e.g. with
strace (edited for clarity):
# ip nexthop add id 1 dev lo
# ip nexthop add id 101 group 1
# strace -e recvmsg ip nexthop get id 101
...
recvmsg(... [{nla_len=12, nla_type=NHA_GROUP},
[{id=1, weight=0, resvd1=0x69, resvd2=0x67}]] ...) = 52
The fields are reserved and therefore not currently used. But as they are, they
leak kernel memory, and the fact they are not just zero complicates repurposing
of the fields for new ends. Initialize the full structure.
Fixes: 430a049190de ("nexthop: Add support for nexthop groups")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/nexthop.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 535856b0f0edc..6b9787ee86017 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -888,9 +888,10 @@ static int nla_put_nh_group(struct sk_buff *skb, struct nexthop *nh,
p = nla_data(nla);
for (i = 0; i < nhg->num_nh; ++i) {
- p->id = nhg->nh_entries[i].nh->id;
- p->weight = nhg->nh_entries[i].weight - 1;
- p += 1;
+ *p++ = (struct nexthop_grp) {
+ .id = nhg->nh_entries[i].nh->id,
+ .weight = nhg->nh_entries[i].weight - 1,
+ };
}
if (nhg->resilient && nla_put_nh_group_res(skb, nhg))
--
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