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ipv4: Fix potential uninit variable access bug in __ip_make_skb()

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Like commit ea30388bae ("ipv6: Fix an uninit variable access bug in
__ip6_make_skb()"). icmphdr does not in skb linear region under the
scenario of SOCK_RAW socket. Access icmp_hdr(skb)->type directly will
trigger the uninit variable access bug.

Use a local variable icmp_type to carry the correct value in different
scenarios.

Fixes: 96793b4825 ("[IPV4]: Add ICMPMsgStats MIB (RFC 4293)")
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ziyang Xuan 2023-04-20 20:40:35 +08:00 committed by David S. Miller
parent 6e79bd28ab
commit 99e5acae19
1 changed files with 13 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

16
net/ipv4/ip_output.c
View file

@ -1570,9 +1570,19 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
cork->dst = NULL;
skb_dst_set(skb, &rt->dst);
if (iph->protocol == IPPROTO_ICMP)
icmp_out_count(net, ((struct icmphdr *)
skb_transport_header(skb))->type);
if (iph->protocol == IPPROTO_ICMP) {
u8 icmp_type;
/* For such sockets, transhdrlen is zero when do ip_append_data(),
* so icmphdr does not in skb linear region and can not get icmp_type
* by icmp_hdr(skb)->type.
*/
if (sk->sk_type == SOCK_RAW && !inet_sk(sk)->hdrincl)
icmp_type = fl4->fl4_icmp_type;
else
icmp_type = icmp_hdr(skb)->type;
icmp_out_count(net, icmp_type);
}
ip_cork_release(cork);
out: