diff options
| author | Wang Yufen <wangyufen@huawei.com> | 2022-06-07 20:00:28 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-06-08 10:56:43 -0700 |
| commit | f638a84afef3dfe10554c51820c16e39a278c915 (patch) | |
| tree | 45041ede5c3dc94a1f0765a8dc8417d34fe98f0e /net/l2tp | |
| parent | f93431c86b631bbca5614c66f966bf3ddb3c2803 (diff) | |
| download | lwn-f638a84afef3dfe10554c51820c16e39a278c915.tar.gz lwn-f638a84afef3dfe10554c51820c16e39a278c915.zip | |
ipv6: Fix signed integer overflow in l2tp_ip6_sendmsg
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: Wang Yufen <wangyufen@huawei.com>
Link: https://lore.kernel.org/r/20220607120028.845916-2-wangyufen@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/l2tp')
| -rw-r--r-- | net/l2tp/l2tp_ip6.c | 5 |
1 files 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) |