5.4-stable review patch. If anyone has any objections, please let me know.
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From: Petr Machata petrm@nvidia.com
[ Upstream commit 6d745cd0e9720282cd291d36b9db528aea18add2 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- 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 0137854a7faaa..388f5773b88d2 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -201,9 +201,10 @@ static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg)
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, + }; }
return 0;