From: Shigeru Yoshida syoshida@redhat.com

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 Signed-off-by: Shubham Kulkarni skulkarni@mvista.com --- Referred stable v6.1.y version of the patch to generate this one [ v6.1 link: https://github.com/gregkh/linux/commit/a05c1ede50e9656f0752e523c7b54f3a3489e... ] --- net/ipv6/ip6_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 426330b8dfa4..99ee18b3a953 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1917,7 +1917,8 @@ 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;