ipv6: raw: Deduct extension header length in rawv6_push_pending_frames

stable inclusion
from stable-v5.10.164
commit 6c9e2c11c33c35563d34d12b343d43b5c12200b5
category: bugfix
bugzilla: 188291, https://gitee.com/src-openeuler/kernel/issues/I6B1V2
CVE: CVE-2023-0394

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c9e2c11c33c35563d34d12b343d43b5c12200b5

--------------------------------

commit cb3e9864 upstream.

The total cork length created by ip6_append_data includes extension
headers, so we must exclude them when comparing them against the
IPV6_CHECKSUM offset which does not include extension headers.
Reported-by: NKyle Zeng <zengyhkyle@gmail.com>
Fixes: 357b40a1 ("[IPV6]: IPV6_CHECKSUM socket option can corrupt kernel memory")
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLu Wei <luwei32@huawei.com>
Reviewed-by: NLiu Jian <liujian56@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

net/ipv6/raw.c

@@ -539,6 +539,7 @@ static int rawv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 static int rawv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
 				     struct raw6_sock *rp)
 {
+	struct ipv6_txoptions *opt;
 	struct sk_buff *skb;
 	int err = 0;
 	int offset;
@@ -556,6 +557,9 @@ static int rawv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
 
 	offset = rp->offset;
 	total_len = inet_sk(sk)->cork.base.length;
+	opt = inet6_sk(sk)->cork.opt;
+	total_len -= opt ? opt->opt_flen : 0;
+
 	if (offset >= total_len - 1) {
 		err = -EINVAL;
 		ip6_flush_pending_frames(sk);