[PATCH 4.19 055/131] ipv6: fix restrict IPV6_ADDRFORM operation

From: Greg Kroah-Hartman
Date: Tue Apr 28 2020 - 14:55:10 EST


From: John Haxby <john.haxby@xxxxxxxxxx>

[ Upstream commit 82c9ae440857840c56e05d4fb1427ee032531346 ]

Commit b6f6118901d1 ("ipv6: restrict IPV6_ADDRFORM operation") fixed a
problem found by syzbot an unfortunate logic error meant that it
also broke IPV6_ADDRFORM.

Rearrange the checks so that the earlier test is just one of the series
of checks made before moving the socket from IPv6 to IPv4.

Fixes: b6f6118901d1 ("ipv6: restrict IPV6_ADDRFORM operation")
Signed-off-by: John Haxby <john.haxby@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ipv6_sockglue.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -185,15 +185,14 @@ static int do_ipv6_setsockopt(struct soc
retv = -EBUSY;
break;
}
- } else if (sk->sk_protocol == IPPROTO_TCP) {
- if (sk->sk_prot != &tcpv6_prot) {
- retv = -EBUSY;
- break;
- }
- break;
- } else {
+ }
+ if (sk->sk_protocol == IPPROTO_TCP &&
+ sk->sk_prot != &tcpv6_prot) {
+ retv = -EBUSY;
break;
}
+ if (sk->sk_protocol != IPPROTO_TCP)
+ break;
if (sk->sk_state != TCP_ESTABLISHED) {
retv = -ENOTCONN;
break;