[PATCH 4.9 001/128] ipv6: fix IPV6_ADDRFORM operation logic

Greg Kroah-Hartman
2020-06-19T16:49:11Z

From: Hangbin Liu <liuhangbin@gmail.com>

[ Upstream commit 79a1f0ccdbb4ad700590f61b00525b390cb53905 ]

Socket option IPV6_ADDRFORM supports UDP/UDPLITE and TCP at present.
Previously the checking logic looks like:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
else if (sk->sk_protocol != IPPROTO_TCP)
break;

After commit b6f6118901d1 ("ipv6: restrict IPV6_ADDRFORM operation"), TCP
was blocked as the logic changed to:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
else if (sk->sk_protocol == IPPROTO_TCP)
do_some_check;
break;
else
break;

Then after commit 82c9ae440857 ("ipv6: fix restrict IPV6_ADDRFORM operation")
UDP/UDPLITE were blocked as the logic changed to:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
if (sk->sk_protocol == IPPROTO_TCP)
do_some_check;

if (sk->sk_protocol != IPPROTO_TCP)
break;

Fix it by using Eric's code and simply remove the break in TCP check, which
looks like:
if (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_UDPLITE)
do_some_check;
else if (sk->sk_protocol == IPPROTO_TCP)
do_some_check;
else
break;

Fixes: 82c9ae440857 ("ipv6: fix restrict IPV6_ADDRFORM operation")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/ipv6_sockglue.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -184,14 +184,15 @@ static int do_ipv6_setsockopt(struct soc
retv = -EBUSY;
break;
}
- }
- if (sk->sk_protocol == IPPROTO_TCP &&
- sk->sk_prot != &tcpv6_prot) {
- retv = -EBUSY;
+ } else if (sk->sk_protocol == IPPROTO_TCP) {
+ if (sk->sk_prot != &tcpv6_prot) {
+ retv = -EBUSY;
+ break;
+ }
+ } else {
break;
}
- if (sk->sk_protocol != IPPROTO_TCP)
- break;
+
if (sk->sk_state != TCP_ESTABLISHED) {
retv = -ENOTCONN;
break;