From: Wang Yufen <wangyufen@huawei.com>
To: <davem@davemloft.net>, <yoshfuji@linux-ipv6.org>,
<dsahern@kernel.org>, <edumazet@google.com>, <kuba@kernel.org>,
<pabeni@redhat.com>, <ast@kernel.org>, <daniel@iogearbox.net>,
<andrii@kernel.org>, <kafai@fb.com>, <songliubraving@fb.com>,
<yhs@fb.com>, <john.fastabend@gmail.com>, <kpsingh@kernel.org>
Cc: <netdev@vger.kernel.org>, <bpf@vger.kernel.org>
Subject: [PATCH net-next v5 2/2] ipv6: Fix signed integer overflow in l2tp_ip6_sendmsg
Date: Tue, 7 Jun 2022 20:00:28 +0800 [thread overview]
Message-ID: <20220607120028.845916-2-wangyufen@huawei.com> (raw)
In-Reply-To: <20220607120028.845916-1-wangyufen@huawei.com>
When len >= INT_MAX - transhdrlen, ulen = len + transhdrlen will be
overflow. To fix, we can follow what udpv6 does and subtract the
transhdrlen from the max.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
---
net/l2tp/l2tp_ip6.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index c6ff8bf9b55f..9dbd801ddb98 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -504,14 +504,15 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
struct ipcm6_cookie ipc6;
int addr_len = msg->msg_namelen;
int transhdrlen = 4; /* zero session-id */
- int ulen = len + transhdrlen;
+ int ulen;
int err;
/* Rough check on arithmetic overflow,
* better check is made in ip6_append_data().
*/
- if (len > INT_MAX)
+ if (len > INT_MAX - transhdrlen)
return -EMSGSIZE;
+ ulen = len + transhdrlen;
/* Mirror BSD error message compatibility */
if (msg->msg_flags & MSG_OOB)
--
2.25.1
next prev parent reply other threads:[~2022-06-07 11:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-07 12:00 [PATCH net-next v5 1/2] ipv6: Fix signed integer overflow in __ip6_append_data Wang Yufen
2022-06-07 12:00 ` Wang Yufen [this message]
2022-06-08 18:30 ` patchwork-bot+netdevbpf
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