The MTU overhead calculation in L2TP device set-up
merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
needs to be adjusted to lock the tunnel socket while
referencing the sub-data structures to derive the
socket's IP overhead.
---
include/linux/net.h | 2 +-
net/l2tp/l2tp_eth.c | 2 ++
net/socket.c | 2 +-
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/net.h b/include/linux/net.h
index a42fab2..abcfa46 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -298,7 +298,7 @@ int kernel_sendpage(struct socket *sock, struct page *page, int offset,
int kernel_sock_ioctl(struct socket *sock, int cmd, unsigned long arg);
int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how);
-/* Following routine returns the IP overhead imposed by a socket. */
+/* Routine returns the IP overhead imposed by a (caller-protected) socket. */
u32 kernel_sock_ip_overhead(struct sock *sk);
#define MODULE_ALIAS_NETPROTO(proto) \
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index 138566a..b722d55 100644
--- a/net/l2tp/l2tp_eth.c
+++ b/net/l2tp/l2tp_eth.c
@@ -225,7 +225,9 @@ static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
dev->needed_headroom += session->hdr_len;
return;
}
+ lock_sock(tunnel->sock);
l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
+ release_sock(tunnel->sock);
if (l3_overhead == 0) {
/* L3 Overhead couldn't be identified, this could be
* because tunnel->sock was NULL or the socket's
diff --git a/net/socket.c b/net/socket.c
index eea9970..c2564eb 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -3360,7 +3360,7 @@ EXPORT_SYMBOL(kernel_sock_shutdown);
/* This routine returns the IP overhead imposed by a socket i.e.
* the length of the underlying IP header, depending on whether
* this is an IPv4 or IPv6 socket and the length from IP options turned
- * on at the socket.
+ * on at the socket. Assumes that the caller has a lock on the socket.
*/
u32 kernel_sock_ip_overhead(struct sock *sk)
{
--
2.1.4
On Tue, Apr 11, 2017 at 08:14:37PM -0700, R. Parameswaran wrote:
>
> The MTU overhead calculation in L2TP device set-up
> merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
> needs to be adjusted to lock the tunnel socket while
> referencing the sub-data structures to derive the
> socket's IP overhead.
Thanks.
Tested-by: Guillaume Nault <[email protected]>
BTW, you don't need to add "v1" for the first version of a patch.
There's also no need for numbering pathes when there's only one in the
series. And we normally prefix the commit message with "<subsystem>: ".
For this patch, your subject would look like " [PATCH net-next] l2tp: ...".
Also, you could have added a "Reported-by:" tag (I don't really mind
in this case, but that's good practice).
From: "R. Parameswaran" <[email protected]>
Date: Tue, 11 Apr 2017 20:14:37 -0700 (PDT)
>
> The MTU overhead calculation in L2TP device set-up
> merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
> needs to be adjusted to lock the tunnel socket while
> referencing the sub-data structures to derive the
> socket's IP overhead.
This is missing a proper signoff.
The subject line also needs to be fixed "[PATCH net-next] l2tp: " as explained
by Guillaume.
Thanks.
Hi Dave,
Please see inline:
On Wed, Apr 12, 2017 at 7:13 AM, David Miller <[email protected]> wrote:
> From: "R. Parameswaran" <[email protected]>
> Date: Tue, 11 Apr 2017 20:14:37 -0700 (PDT)
>
>>
>> The MTU overhead calculation in L2TP device set-up
>> merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
>> needs to be adjusted to lock the tunnel socket while
>> referencing the sub-data structures to derive the
>> socket's IP overhead.
>
> This is missing a proper signoff.
>
> The subject line also needs to be fixed "[PATCH net-next] l2tp: " as explained
> by Guillaume.
>
Thanks, I will re-spin with these corrections by tonight PT.
regards,
Ramkumar
> Thanks.
Hi Guillaume,
Please see inline:
On Wed, Apr 12, 2017 at 12:53 AM, Guillaume Nault <[email protected]> wrote:
> On Tue, Apr 11, 2017 at 08:14:37PM -0700, R. Parameswaran wrote:
>>
>> The MTU overhead calculation in L2TP device set-up
>> merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
>> needs to be adjusted to lock the tunnel socket while
>> referencing the sub-data structures to derive the
>> socket's IP overhead.
>
> Thanks.
>
> Tested-by: Guillaume Nault <[email protected]>
>
> BTW, you don't need to add "v1" for the first version of a patch.
> There's also no need for numbering pathes when there's only one in the
> series. And we normally prefix the commit message with "<subsystem>: ".
> For this patch, your subject would look like " [PATCH net-next] l2tp: ...".
>
> Also, you could have added a "Reported-by:" tag (I don't really mind
> in this case, but that's good practice).
Thanks for correcting these (and for testing the changes) and sorry
for the Reported-by omission. I'll respin by tonight
with these, per reply to Dave.
regards,
Ramkumar