From: Petr Machata petrm@nvidia.com

stable inclusion from stable-v5.10.224 commit 5cc4d71dda2dd4f1520f40e634a527022e48ccd8 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAKPWF CVE: CVE-2024-42283

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ 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 Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com --- 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 2a17dc9413ae..67829ff8f921 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -210,9 +210,10 @@ 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;