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| author | Wang Yufen <wangyufen@huawei.com> | 2022-06-07 15:00:28 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-22 15:11:21 +0300 |
| commit | 2f42389d270f2304c8855b0b63498a5a4d0c053d (patch) | |
| tree | 1b9f9be3481b11fd6ab29fa91420b83028d27325 | |
| parent | 6b4d8b44e7163a77fe942f5b80e1651c1b78c537 (diff) | |
| download | linux-2f42389d270f2304c8855b0b63498a5a4d0c053d.tar.xz | |
ipv6: Fix signed integer overflow in l2tp_ip6_sendmsg
[ Upstream commit f638a84afef3dfe10554c51820c16e39a278c915 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 0fa694bd3f6a..23e9ce985ed6 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -515,14 +515,15 @@ 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) |