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

[ Upstream commit 4e13d3a9c25b7080f8a619f961e943fe08c2672c ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 31b86fe661aa6cd94fb5d8848900406c2db110e3..568065a015c4166598a97ad153a9bf621ca2de56 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1933,7 +1933,7 @@ struct sk_buff *__ip6_make_skb(struct sock *sk,
                u8 icmp6_type;
 
                if (sk->sk_socket->type == SOCK_RAW &&
-                  !inet_test_bit(HDRINCL, sk))
+                  !(fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH))
                        icmp6_type = fl6->fl6_icmp_type;
                else
                        icmp6_type = icmp6_hdr(skb)->icmp6_type;