pull request (net-next): ipsec-next 2017-12-15

pull request (net-next): ipsec-next 2017-12-15

[Steffen Klassert]

1) Currently we can add or update socket policies, but
   not clear them. Support clearing of socket policies
   too. From Lorenzo Colitti.

2) Add documentation for the xfrm device offload api.
   From Shannon Nelson.

3) Fix IPsec extended sequence numbers (ESN) for
   IPsec offloading. From Yossef Efraim.

4) xfrm_dev_state_add function returns success even for
   unsupported options, fix this to fail in such cases.
   From Yossef Efraim.

5) Remove a redundant xfrm_state assignment.
   From Aviv Heller.

Please pull or let me know if there are problems.

Thanks!

The following changes since commit b9151761021e25c024a6670df4e7c43ffbab0e1d:

  Merge tag 'nfsd-4.15-1' of git://linux-nfs.org/~bfields/linux (2017-11-29 14:49:26 -0800)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next.git master

for you to fetch changes up to 9b7e14dba0c087e950fc024b486e8f729c1ee672:

  xfrm: Remove redundant state assignment in xfrm_input() (2017-12-01 07:41:48 +0100)

----------------------------------------------------------------
Aviv Heller (1):
      xfrm: Remove redundant state assignment in xfrm_input()

Lorenzo Colitti (1):
      net: xfrm: allow clearing socket xfrm policies.

Shannon Nelson (1):
      xfrm: add documentation for xfrm device offload api

Yossef Efraim (2):
      xfrm: Fix xfrm_replay_overflow_offload_esn
      xfrm: Fix xfrm_dev_state_add to fail for unsupported HW SA option

 Documentation/networking/00-INDEX        |   2 +
 Documentation/networking/xfrm_device.txt | 132 +++++++++++++++++++++++++++++++
 net/xfrm/xfrm_device.c                   |   2 +-
 net/xfrm/xfrm_input.c                    |   1 -
 net/xfrm/xfrm_policy.c                   |   2 +-
 net/xfrm/xfrm_replay.c                   |   3 +-
 net/xfrm/xfrm_state.c                    |   7 ++
 7 files changed, 144 insertions(+), 5 deletions(-)
 create mode 100644 Documentation/networking/xfrm_device.txt

[PATCH 1/5] net: xfrm: allow clearing socket xfrm policies.

[Steffen Klassert]

From: Lorenzo Colitti <lorenzo@google.com>

Currently it is possible to add or update socket policies, but
not clear them. Therefore, once a socket policy has been applied,
the socket cannot be used for unencrypted traffic.

This patch allows (privileged) users to clear socket policies by
passing in a NULL pointer and zero length argument to the
{IP,IPV6}_{IPSEC,XFRM}_POLICY setsockopts. This results in both
the incoming and outgoing policies being cleared.

The simple approach taken in this patch cannot clear socket
policies in only one direction. If desired this could be added
in the future, for example by continuing to pass in a length of
zero (which currently is guaranteed to return EMSGSIZE) and
making the policy be a pointer to an integer that contains one
of the XFRM_POLICY_{IN,OUT} enum values.

An alternative would have been to interpret the length as a
signed integer and use XFRM_POLICY_IN (i.e., 0) to clear the
input policy and -XFRM_POLICY_OUT (i.e., -1) to clear the output
policy.

Tested: https://android-review.googlesource.com/539816
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_policy.c | 2 +-
 net/xfrm/xfrm_state.c  | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 9542975eb2f9..3263662fb20a 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1251,7 +1251,7 @@ EXPORT_SYMBOL(xfrm_policy_delete);
 
 int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol)
 {
-	struct net *net = xp_net(pol);
+	struct net *net = sock_net(sk);
 	struct xfrm_policy *old_pol;
 
 #ifdef CONFIG_XFRM_SUB_POLICY
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 065d89606888..1b7856be3eeb 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2048,6 +2048,13 @@ int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen
 	struct xfrm_mgr *km;
 	struct xfrm_policy *pol = NULL;
 
+	if (!optval && !optlen) {
+		xfrm_sk_policy_insert(sk, XFRM_POLICY_IN, NULL);
+		xfrm_sk_policy_insert(sk, XFRM_POLICY_OUT, NULL);
+		__sk_dst_reset(sk);
+		return 0;
+	}
+
 	if (optlen <= 0 || optlen > PAGE_SIZE)
 		return -EMSGSIZE;
 
-- 
2.14.1

[PATCH 2/5] xfrm: add documentation for xfrm device offload api

[Steffen Klassert]

From: Shannon Nelson <shannon.nelson@oracle.com>

Add a writeup on how to use the XFRM device offload API, and
mention this new file in the index.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 Documentation/networking/00-INDEX        |   2 +
 Documentation/networking/xfrm_device.txt | 132 +++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 Documentation/networking/xfrm_device.txt

diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX
index 7a79b3587dd3..f5d642c01dd3 100644
--- a/Documentation/networking/00-INDEX
+++ b/Documentation/networking/00-INDEX
@@ -228,6 +228,8 @@ x25.txt
 	- general info on X.25 development.
 x25-iface.txt
 	- description of the X.25 Packet Layer to LAPB device interface.
+xfrm_device.txt
+	- description of XFRM offload API
 xfrm_proc.txt
 	- description of the statistics package for XFRM.
 xfrm_sync.txt
diff --git a/Documentation/networking/xfrm_device.txt b/Documentation/networking/xfrm_device.txt
new file mode 100644
index 000000000000..2d9d588cd34b
--- /dev/null
+++ b/Documentation/networking/xfrm_device.txt
@@ -0,0 +1,132 @@
+
+===============================================
+XFRM device - offloading the IPsec computations
+===============================================
+Shannon Nelson <shannon.nelson@oracle.com>
+
+
+Overview
+========
+
+IPsec is a useful feature for securing network traffic, but the
+computational cost is high: a 10Gbps link can easily be brought down
+to under 1Gbps, depending on the traffic and link configuration.
+Luckily, there are NICs that offer a hardware based IPsec offload which
+can radically increase throughput and decrease CPU utilization.  The XFRM
+Device interface allows NIC drivers to offer to the stack access to the
+hardware offload.
+
+Userland access to the offload is typically through a system such as
+libreswan or KAME/raccoon, but the iproute2 'ip xfrm' command set can
+be handy when experimenting.  An example command might look something
+like this:
+
+  ip x s add proto esp dst 14.0.0.70 src 14.0.0.52 spi 0x07 mode transport \
+     reqid 0x07 replay-window 32 \
+     aead 'rfc4106(gcm(aes))' 0x44434241343332312423222114131211f4f3f2f1 128 \
+     sel src 14.0.0.52/24 dst 14.0.0.70/24 proto tcp \
+     offload dev eth4 dir in
+
+Yes, that's ugly, but that's what shell scripts and/or libreswan are for.
+
+
+
+Callbacks to implement
+======================
+
+/* from include/linux/netdevice.h */
+struct xfrmdev_ops {
+	int	(*xdo_dev_state_add) (struct xfrm_state *x);
+	void	(*xdo_dev_state_delete) (struct xfrm_state *x);
+	void	(*xdo_dev_state_free) (struct xfrm_state *x);
+	bool	(*xdo_dev_offload_ok) (struct sk_buff *skb,
+				       struct xfrm_state *x);
+};
+
+The NIC driver offering ipsec offload will need to implement these
+callbacks to make the offload available to the network stack's
+XFRM subsytem.  Additionally, the feature bits NETIF_F_HW_ESP and
+NETIF_F_HW_ESP_TX_CSUM will signal the availability of the offload.
+
+
+
+Flow
+====
+
+At probe time and before the call to register_netdev(), the driver should
+set up local data structures and XFRM callbacks, and set the feature bits.
+The XFRM code's listener will finish the setup on NETDEV_REGISTER.
+
+		adapter->netdev->xfrmdev_ops = &ixgbe_xfrmdev_ops;
+		adapter->netdev->features |= NETIF_F_HW_ESP;
+		adapter->netdev->hw_enc_features |= NETIF_F_HW_ESP;
+
+When new SAs are set up with a request for "offload" feature, the
+driver's xdo_dev_state_add() will be given the new SA to be offloaded
+and an indication of whether it is for Rx or Tx.  The driver should
+	- verify the algorithm is supported for offloads
+	- store the SA information (key, salt, target-ip, protocol, etc)
+	- enable the HW offload of the SA
+
+The driver can also set an offload_handle in the SA, an opaque void pointer
+that can be used to convey context into the fast-path offload requests.
+
+		xs->xso.offload_handle = context;
+
+
+When the network stack is preparing an IPsec packet for an SA that has
+been setup for offload, it first calls into xdo_dev_offload_ok() with
+the skb and the intended offload state to ask the driver if the offload
+will serviceable.  This can check the packet information to be sure the
+offload can be supported (e.g. IPv4 or IPv6, no IPv4 options, etc) and
+return true of false to signify its support.
+
+When ready to send, the driver needs to inspect the Tx packet for the
+offload information, including the opaque context, and set up the packet
+send accordingly.
+
+		xs = xfrm_input_state(skb);
+		context = xs->xso.offload_handle;
+		set up HW for send
+
+The stack has already inserted the appropriate IPsec headers in the
+packet data, the offload just needs to do the encryption and fix up the
+header values.
+
+
+When a packet is received and the HW has indicated that it offloaded a
+decryption, the driver needs to add a reference to the decoded SA into
+the packet's skb.  At this point the data should be decrypted but the
+IPsec headers are still in the packet data; they are removed later up
+the stack in xfrm_input().
+
+	find and hold the SA that was used to the Rx skb
+		get spi, protocol, and destination IP from packet headers
+		xs = find xs from (spi, protocol, dest_IP)
+		xfrm_state_hold(xs);
+
+	store the state information into the skb
+		skb->sp = secpath_dup(skb->sp);
+		skb->sp->xvec[skb->sp->len++] = xs;
+		skb->sp->olen++;
+
+	indicate the success and/or error status of the offload
+		xo = xfrm_offload(skb);
+		xo->flags = CRYPTO_DONE;
+		xo->status = crypto_status;
+
+	hand the packet to napi_gro_receive() as usual
+
+
+When the SA is removed by the user, the driver's xdo_dev_state_delete()
+is asked to disable the offload.  Later, xdo_dev_state_free() is called
+from a garbage collection routine after all reference counts to the state
+have been removed and any remaining resources can be cleared for the
+offload state.  How these are used by the driver will depend on specific
+hardware needs.
+
+As a netdev is set to DOWN the XFRM stack's netdev listener will call
+xdo_dev_state_delete() and xdo_dev_state_free() on any remaining offloaded
+states.
+
+
-- 
2.14.1

[PATCH 3/5] xfrm: Fix xfrm_replay_overflow_offload_esn

[Steffen Klassert]

From: Yossef Efraim <yossefe@mellanox.com>

In case of wrap around, replay_esn->oseq_hi is not updated
before it is tested for it's actual value, leading function
to fail with overflow indication and packets being dropped.

This patch updates replay_esn->oseq_hi in the right place.

Fixes: d7dbefc45cf5 ("xfrm: Add xfrm_replay_overflow functions for offloading")
Signed-off-by: Yossef Efraim <yossefe@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_replay.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index 8b23c5bcf8e8..02501817227b 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -666,7 +666,7 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 		if (unlikely(oseq < replay_esn->oseq)) {
 			XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
 			xo->seq.hi = oseq_hi;
-
+			replay_esn->oseq_hi = oseq_hi;
 			if (replay_esn->oseq_hi == 0) {
 				replay_esn->oseq--;
 				replay_esn->oseq_hi--;
@@ -678,7 +678,6 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
 		}
 
 		replay_esn->oseq = oseq;
-		replay_esn->oseq_hi = oseq_hi;
 
 		if (xfrm_aevent_is_on(net))
 			x->repl->notify(x, XFRM_REPLAY_UPDATE);
-- 
2.14.1

[PATCH 4/5] xfrm: Fix xfrm_dev_state_add to fail for unsupported HW SA option

[Steffen Klassert]

From: Yossef Efraim <yossefe@mellanox.com>

xfrm_dev_state_add function returns success for unsupported HW SA options.
Resulting the calling function to create SW SA without corrlating HW SA.
Desipte IPSec device offloading option was chosen.
These not supported HW SA options are hard coded within xfrm_dev_state_add
function.
SW backward compatibility will break if we add any of these option as old
HW will fail with new SW.

This patch changes the behaviour to return -EINVAL in case unsupported
option is chosen.
Notifying user application regarding failure and not breaking backward
compatibility for newly added HW SA options.

Signed-off-by: Yossef Efraim <yossefe@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 30e5746085b8..dc68d9c1fc8f 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -67,7 +67,7 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 
 	/* We don't yet support UDP encapsulation, TFC padding and ESN. */
 	if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
-		return 0;
+		return -EINVAL;
 
 	dev = dev_get_by_index(net, xuo->ifindex);
 	if (!dev) {
-- 
2.14.1

[PATCH 5/5] xfrm: Remove redundant state assignment in xfrm_input()

[Steffen Klassert]

From: Aviv Heller <avivh@mellanox.com>

x is already initialized to the same value, above.

Signed-off-by: Aviv Heller <avivh@mellanox.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_input.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 347ab31574d5..ac277b97e0d7 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -231,7 +231,6 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 
 		if (xo && (xo->flags & CRYPTO_DONE)) {
 			crypto_done = true;
-			x = xfrm_input_state(skb);
 			family = XFRM_SPI_SKB_CB(skb)->family;
 
 			if (!(xo->status & CRYPTO_SUCCESS)) {
-- 
2.14.1

Re: pull request (net-next): ipsec-next 2017-12-15

[David Miller]

From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Fri, 15 Dec 2017 13:19:47 +0100

> 1) Currently we can add or update socket policies, but
>    not clear them. Support clearing of socket policies
>    too. From Lorenzo Colitti.
> 
> 2) Add documentation for the xfrm device offload api.
>    From Shannon Nelson.
> 
> 3) Fix IPsec extended sequence numbers (ESN) for
>    IPsec offloading. From Yossef Efraim.
> 
> 4) xfrm_dev_state_add function returns success even for
>    unsupported options, fix this to fail in such cases.
>    From Yossef Efraim.
> 
> 5) Remove a redundant xfrm_state assignment.
>    From Aviv Heller.
> 
> Please pull or let me know if there are problems.

Pulled, thank you Steffen.