* [PATCH] net-ipv6: add support for sockopt(SOL_IPV6, IPV6_FREEBIND)
@ 2017-09-27 4:32 Maciej Żenczykowski
2017-09-30 4:31 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Maciej Żenczykowski @ 2017-09-27 4:32 UTC (permalink / raw)
To: Maciej Żenczykowski, David S . Miller; +Cc: netdev
From: Maciej Żenczykowski <maze@google.com>
So far we've been relying on sockopt(SOL_IP, IP_FREEBIND) being usable
even on IPv6 sockets.
However, it turns out it is perfectly reasonable to want to set freebind
on an AF_INET6 SOCK_RAW socket - but there is no way to set any SOL_IP
socket option on such a socket (they're all blindly errored out).
One use case for this is to allow spoofing src ip on a raw socket
via sendmsg cmsg.
Tested:
built, and booted
# python
>>> import socket
>>> SOL_IP = socket.SOL_IP
>>> SOL_IPV6 = socket.IPPROTO_IPV6
>>> IP_FREEBIND = 15
>>> IPV6_FREEBIND = 78
>>> s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, 0)
>>> s.getsockopt(SOL_IP, IP_FREEBIND)
0
>>> s.getsockopt(SOL_IPV6, IPV6_FREEBIND)
0
>>> s.setsockopt(SOL_IPV6, IPV6_FREEBIND, 1)
>>> s.getsockopt(SOL_IP, IP_FREEBIND)
1
>>> s.getsockopt(SOL_IPV6, IPV6_FREEBIND)
1
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
include/uapi/linux/in6.h | 1 +
net/ipv6/ipv6_sockglue.c | 12 ++++++++++++
2 files changed, 13 insertions(+)
diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h
index 46444f8fbee4..4f8f3eb0699f 100644
--- a/include/uapi/linux/in6.h
+++ b/include/uapi/linux/in6.h
@@ -284,6 +284,7 @@ struct in6_flowlabel_req {
#define IPV6_TRANSPARENT 75
#define IPV6_UNICAST_IF 76
#define IPV6_RECVFRAGSIZE 77
+#define IPV6_FREEBIND 78
/*
* Multicast Routing:
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index a5e466d4e093..b9404feabd78 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -377,6 +377,14 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
retv = 0;
break;
+ case IPV6_FREEBIND:
+ if (optlen < sizeof(int))
+ goto e_inval;
+ /* we also don't have a separate freebind bit for IPV6 */
+ inet_sk(sk)->freebind = valbool;
+ retv = 0;
+ break;
+
case IPV6_RECVORIGDSTADDR:
if (optlen < sizeof(int))
goto e_inval;
@@ -1214,6 +1222,10 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
val = inet_sk(sk)->transparent;
break;
+ case IPV6_FREEBIND:
+ val = inet_sk(sk)->freebind;
+ break;
+
case IPV6_RECVORIGDSTADDR:
val = np->rxopt.bits.rxorigdstaddr;
break;
--
2.14.1.992.g2c7b836f3a-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net-ipv6: add support for sockopt(SOL_IPV6, IPV6_FREEBIND)
2017-09-27 4:32 [PATCH] net-ipv6: add support for sockopt(SOL_IPV6, IPV6_FREEBIND) Maciej Żenczykowski
@ 2017-09-30 4:31 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2017-09-30 4:31 UTC (permalink / raw)
To: zenczykowski; +Cc: maze, netdev
From: Maciej Żenczykowski <zenczykowski@gmail.com>
Date: Tue, 26 Sep 2017 21:32:42 -0700
> From: Maciej Żenczykowski <maze@google.com>
>
> So far we've been relying on sockopt(SOL_IP, IP_FREEBIND) being usable
> even on IPv6 sockets.
>
> However, it turns out it is perfectly reasonable to want to set freebind
> on an AF_INET6 SOCK_RAW socket - but there is no way to set any SOL_IP
> socket option on such a socket (they're all blindly errored out).
>
> One use case for this is to allow spoofing src ip on a raw socket
> via sendmsg cmsg.
>
> Tested:
> built, and booted
> # python
> >>> import socket
> >>> SOL_IP = socket.SOL_IP
> >>> SOL_IPV6 = socket.IPPROTO_IPV6
> >>> IP_FREEBIND = 15
> >>> IPV6_FREEBIND = 78
> >>> s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM, 0)
> >>> s.getsockopt(SOL_IP, IP_FREEBIND)
> 0
> >>> s.getsockopt(SOL_IPV6, IPV6_FREEBIND)
> 0
> >>> s.setsockopt(SOL_IPV6, IPV6_FREEBIND, 1)
> >>> s.getsockopt(SOL_IP, IP_FREEBIND)
> 1
> >>> s.getsockopt(SOL_IPV6, IPV6_FREEBIND)
> 1
>
> Signed-off-by: Maciej Żenczykowski <maze@google.com>
Applied to net-next, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-09-30 4:31 ` David Miller
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