[PATCH 6.6 191/301] ipv6: Fix potential uninit-value access in __ip6_make_skb()

Greg Kroah-Hartman
2024-05-14T11:17:37Z

From: Shigeru Yoshida <syoshida@redhat.com>

[ 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>
---
net/ipv6/ip6_output.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 53fe1375b147c..fba789cbd215c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -2003,7 +2003,7 @@ 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;
--
2.43.0