On Thu, 2015-11-12 at 10:48 +0100, Sabrina Dubroca wrote:
> 2015-11-10, 16:03:52 -0800, Greg Kroah-Hartman wrote:
> > On Tue, Nov 10, 2015 at 05:59:26PM -0600, Josh Hunt wrote:
> > > On Thu, Oct 29, 2015 at 5:00 AM, Sabrina Dubroca <sd@xxxxxxxxxxxxxxx> wrote:
> > > > 2015-10-15, 14:25:03 +0200, Sabrina Dubroca wrote:
> > > >> Without this length argument, we can read past the end of the iovec in
> > > >> memcpy_toiovec because we have no way of knowing the total length of the
> > > >> iovec's buffers.
> > > >>
> > > >> This is needed for stable kernels where 89c22d8c3b27 ("net: Fix skb
> > > >> csum races when peeking") has been backported but that don't have the
> > > >> ioviter conversion, which is almost all the stable trees <= 3.18.
> > > >>
> > > >> This also fixes a kernel crash for NFS servers when the client uses
> > > >> -onfsvers=3,proto=udp to mount the export.
> > > >>
> > > >> Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
> > > >> Reviewed-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
> > > >
> > > > Fixes CVE-2015-8019.
> > > > http://www.openwall.com/lists/oss-security/2015/10/29/1
> > > >
> > > > --
> > > > Sabrina
> > > > --
> > > > To unsubscribe from this list: send the line "unsubscribe netdev" in
> > > > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > > > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > >
> > > Greg
> > >
> > > Do you have this in your queue? I saw a few other stables pick this
> > > up, but haven't seen it in 3.14 or 3.18 yet. It wasn't clear to me if
> > > this had been fully reviewed yet.
> >
> > I rely on Dave to package up networking stable patches and forward them
> > on to me, that's why you haven't seen it be picked up yet.
> >
> > thanks,
> >
> > greg k-h
>
> David, can you queue this up?
>
Note that the following patch (and corresponding part for ipv6) might
also have solve the issue ?
This would supposedly save some cycles when MSG_PEEK is used and user
provides short buffers.
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 24ec14f9825c..387acab1ab5c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1272,6 +1272,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
int err;
int is_udplite = IS_UDPLITE(sk);
bool slow;
+ bool checksum_valid = false;
if (flags & MSG_ERRQUEUE)
return ip_recv_error(sk, msg, len, addr_len);
@@ -1296,11 +1297,12 @@ try_again:
*/
if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
- if (udp_lib_checksum_complete(skb))
+ checksum_valid = !udp_lib_checksum_complete(skb);
+ if (!checksum_valid)
goto csum_copy_err;
}
- if (skb_csum_unnecessary(skb))
+ if (checksum_valid || skb_csum_unnecessary(skb))
err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
msg, copied);
else {
--
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