ipv6: Fix potential uninit-value access in __ip6_make_skb()

commit 4e13d3a9c25b7080f8a619f961e943fe08c2672c upstream.

As it was done in commit fc1092f51567 ("ipv4: Fix uninit-value access in
__ip_make_skb()") for IPv4, check FLOWI_FLAG_KNOWN_NH on fl6->flowi6_flags
instead of testing HDRINCL on the socket to avoid a race condition which
causes uninit-value access.

Fixes: ea30388baebc ("ipv6: Fix an uninit variable access bug in __ip6_make_skb()")
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Referred stable v6.1.y version of the patch to generate this one
link: https://github.com/gregkh/linux/commit/a05c1ede50e9656f0752e523c7b54f3a3489e9a8
Signed-off-by: Shubham Kulkarni <skulkarni@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 4fcff4fe5a98f4f7524920c3aefa48f7c9693cf9..acb76248cc0e479d1753cdd917b2b1179884484f 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1928,7 +1928,8 @@ struct sk_buff *__ip6_make_skb(struct sock *sk,
                struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
                u8 icmp6_type;
 
-               if (sk->sk_socket->type == SOCK_RAW && !inet_sk(sk)->hdrincl)
+               if (sk->sk_socket->type == SOCK_RAW &&
+                   !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH))
                        icmp6_type = fl6->fl6_icmp_type;
                else
                        icmp6_type = icmp6_hdr(skb)->icmp6_type;