[PATCHv2 net-next 0/5] xfrm: Add ESN support for AH

[PATCHv2 net-next 0/5] xfrm: Add ESN support for AH

[Fan Du]

Hi,

This is initial Extended Sequence Number support for AH based on IPv4.
The rationale is totally by the RFC 4302, which states:

3.3.3.2.2.  Implicit Packet Padding and ESN

   If the ESN option is elected for an SA, then the high-order 32 bits
   of the ESN must be included in the ICV computation.  For purposes of
   ICV computation, these bits are appended (implicitly) immediately
   after the end of the payload, and before any implicit packet padding.

So we attach the high-order 32bits as a scatterlist right after the packet
payload to compute ICV value. 

Test:
I add a knob in iproute2/ip/xfrm_state.c to enable esn when setting SA,
which make it possible to test with-esn and without-esn scenarios, both
cases works ok with ping using packetsize(-s) from default to 32768. 

v2:
  - Patch3/5 and Patch4/5 add IPv6 part as requested by Steffen.
  - Patch5/5 restrict ESN feature only to ESP and AH.

Fan Du (5):
  {IPv4,xfrm} Add ESN support for AH egress part
  {IPv4,xfrm} Add ESN support for AH ingress part
  {IPv6,xfrm} Add ESN support for AH egress part
  {IPv6,xfrm} Add ESN support for AH ingress part
  xfrm: Don't prohibit AH from using ESN feature

 net/ipv4/ah4.c       |   50 +++++++++++++++++++++++++++++++++++++++++-------
 net/ipv6/ah6.c       |   52 +++++++++++++++++++++++++++++++++++++++++++-------
 net/xfrm/xfrm_user.c |    3 ++-
 3 files changed, 90 insertions(+), 15 deletions(-)

-- 
1.7.9.5

[PATCHv2 net-next 1/5] {IPv4,xfrm} Add ESN support for AH egress part

[Fan Du]

This patch add esn support for AH output stage by attaching upper 32bits
sequence number right after packet payload as specified by RFC 4302.

Then the ICV value will guard upper 32bits sequence number as well when
packet going out.

Signed-off-by: Fan Du <fan.du@windriver.com>
---
 net/ipv4/ah4.c |   25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index 7179026..a7fac03 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -12,6 +12,7 @@
 #include <linux/scatterlist.h>
 #include <net/icmp.h>
 #include <net/protocol.h>
+#include <crypto/scatterwalk.h>
 
 struct ah_skb_cb {
 	struct xfrm_skb_cb xfrm;
@@ -155,6 +156,10 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
 	struct iphdr *iph, *top_iph;
 	struct ip_auth_hdr *ah;
 	struct ah_data *ahp;
+	int seqhi_len = 0;
+	__be32 *seqhi;
+	int sglists = 0;
+	struct scatterlist *seqhisg;
 
 	ahp = x->data;
 	ahash = ahp->ahash;
@@ -167,14 +172,19 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
 	ah = ip_auth_hdr(skb);
 	ihl = ip_hdrlen(skb);
 
+	if (x->props.flags & XFRM_STATE_ESN) {
+		sglists = 1;
+		seqhi_len = sizeof(*seqhi);
+	}
 	err = -ENOMEM;
-	iph = ah_alloc_tmp(ahash, nfrags, ihl);
+	iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
 	if (!iph)
 		goto out;
-
-	icv = ah_tmp_icv(ahash, iph, ihl);
+	seqhi = (__be32 *)((char *)iph + ihl);
+	icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
 	req = ah_tmp_req(ahash, icv);
 	sg = ah_req_sg(ahash, req);
+	seqhisg = sg + nfrags;
 
 	memset(ah->auth_data, 0, ahp->icv_trunc_len);
 
@@ -213,7 +223,14 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg, 0, skb->len);
 
-	ahash_request_set_crypt(req, sg, icv, skb->len);
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		sg_unmark_end(&sg[nfrags - 1]);
+		/* Attach seqhi sg right after packet payload */
+		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
+		sg_init_table(seqhisg, sglists);
+		sg_set_buf(seqhisg, seqhi, seqhi_len);
+	}
+	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
 	ahash_request_set_callback(req, 0, ah_output_done, skb);
 
 	AH_SKB_CB(skb)->tmp = iph;
-- 
1.7.9.5

Re: [PATCHv2 net-next 1/5] {IPv4,xfrm} Add ESN support for AH egress part

[Sergei Shtylyov]

Hello.

On 13-01-2014 11:48, Fan Du wrote:

> This patch add esn support for AH output stage by attaching upper 32bits
> sequence number right after packet payload as specified by RFC 4302.

> Then the ICV value will guard upper 32bits sequence number as well when
> packet going out.

> Signed-off-by: Fan Du <fan.du@windriver.com>
> ---
>   net/ipv4/ah4.c |   25 +++++++++++++++++++++----
>   1 file changed, 21 insertions(+), 4 deletions(-)

> diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
> index 7179026..a7fac03 100644
> --- a/net/ipv4/ah4.c
> +++ b/net/ipv4/ah4.c
[...]
> @@ -213,7 +223,14 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
>   	sg_init_table(sg, nfrags);
>   	skb_to_sgvec(skb, sg, 0, skb->len);
>
> -	ahash_request_set_crypt(req, sg, icv, skb->len);
> +	if ((x->props.flags & XFRM_STATE_ESN)) {

    What's the point in double parens here? The same question about the other 
patches....

WBR, Sergei

[PATCHv2 net-next 2/5] {IPv4,xfrm} Add ESN support for AH ingress part

[Fan Du]

This patch add esn support for AH input stage by attaching upper 32bits
sequence number right after packet payload as specified by RFC 4302.

Then the ICV value will guard upper 32bits sequence number as well when
packet getting in.

Signed-off-by: Fan Du <fan.du@windriver.com>
---
 net/ipv4/ah4.c |   25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index a7fac03..984dbd6 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -312,6 +312,10 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 	struct ip_auth_hdr *ah;
 	struct ah_data *ahp;
 	int err = -ENOMEM;
+	int seqhi_len = 0;
+	__be32 *seqhi;
+	int sglists = 0;
+	struct scatterlist *seqhisg;
 
 	if (!pskb_may_pull(skb, sizeof(*ah)))
 		goto out;
@@ -352,14 +356,22 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 	iph = ip_hdr(skb);
 	ihl = ip_hdrlen(skb);
 
-	work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
+	if (x->props.flags & XFRM_STATE_ESN) {
+		sglists = 1;
+		seqhi_len = sizeof(*seqhi);
+	}
+
+	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
+				ahp->icv_trunc_len + seqhi_len);
 	if (!work_iph)
 		goto out;
 
-	auth_data = ah_tmp_auth(work_iph, ihl);
+	seqhi = (__be32 *)((char *)work_iph + ihl);
+	auth_data = ah_tmp_auth(seqhi, seqhi_len);
 	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
 	req = ah_tmp_req(ahash, icv);
 	sg = ah_req_sg(ahash, req);
+	seqhisg = sg + nfrags;
 
 	memcpy(work_iph, iph, ihl);
 	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
@@ -381,7 +393,14 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg, 0, skb->len);
 
-	ahash_request_set_crypt(req, sg, icv, skb->len);
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		sg_unmark_end(&sg[nfrags - 1]);
+		/* Attach seqhi sg right after packet payload */
+		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
+		sg_init_table(seqhisg, sglists);
+		sg_set_buf(seqhisg, seqhi, seqhi_len);
+	}
+	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
 	ahash_request_set_callback(req, 0, ah_input_done, skb);
 
 	AH_SKB_CB(skb)->tmp = work_iph;
-- 
1.7.9.5

[PATCHv2 net-next 3/5] {IPv6,xfrm} Add ESN support for AH egress part

[Fan Du]

This patch add esn support for AH output stage by attaching upper 32bits
sequence number right after packet payload as specified by RFC 4302.

Then the ICV value will guard upper 32bits sequence number as well when
packet going out.

Signed-off-by: Fan Du <fan.du@windriver.com>
---
 net/ipv6/ah6.c |   24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index 81e496a..87826a5 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -346,6 +346,10 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
 	struct ip_auth_hdr *ah;
 	struct ah_data *ahp;
 	struct tmp_ext *iph_ext;
+	int seqhi_len = 0;
+	__be32 *seqhi;
+	int sglists = 0;
+	struct scatterlist *seqhisg;
 
 	ahp = x->data;
 	ahash = ahp->ahash;
@@ -359,15 +363,22 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
 	if (extlen)
 		extlen += sizeof(*iph_ext);
 
+	if (x->props.flags & XFRM_STATE_ESN) {
+		sglists = 1;
+		seqhi_len = sizeof(*seqhi);
+	}
 	err = -ENOMEM;
-	iph_base = ah_alloc_tmp(ahash, nfrags, IPV6HDR_BASELEN + extlen);
+	iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
+				extlen + seqhi_len);
 	if (!iph_base)
 		goto out;
 
 	iph_ext = ah_tmp_ext(iph_base);
-	icv = ah_tmp_icv(ahash, iph_ext, extlen);
+	seqhi = (char *)iph_ext + extlen;
+	icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
 	req = ah_tmp_req(ahash, icv);
 	sg = ah_req_sg(ahash, req);
+	seqhisg = sg + nfrags;
 
 	ah = ip_auth_hdr(skb);
 	memset(ah->auth_data, 0, ahp->icv_trunc_len);
@@ -414,7 +425,14 @@ static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg, 0, skb->len);
 
-	ahash_request_set_crypt(req, sg, icv, skb->len);
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		sg_unmark_end(&sg[nfrags - 1]);
+		/* Attach seqhi sg right after packet payload */
+		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
+		sg_init_table(seqhisg, sglists);
+		sg_set_buf(seqhisg, seqhi, seqhi_len);
+	}
+	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
 	ahash_request_set_callback(req, 0, ah6_output_done, skb);
 
 	AH_SKB_CB(skb)->tmp = iph_base;
-- 
1.7.9.5

[PATCHv2 net-next 4/5] {IPv6,xfrm} Add ESN support for AH ingress part

[Fan Du]

This patch add esn support for AH input stage by attaching upper 32bits
sequence number right after packet payload as specified by RFC 4302.

Then the ICV value will guard upper 32bits sequence number as well when
packet going in.

Signed-off-by: Fan Du <fan.du@windriver.com>
---
 net/ipv6/ah6.c |   28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index 87826a5..7f5c822 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -532,6 +532,10 @@ static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
 	int nexthdr;
 	int nfrags;
 	int err = -ENOMEM;
+	int seqhi_len = 0;
+	__be32 *seqhi;
+	int sglists = 0;
+	struct scatterlist *seqhisg;
 
 	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
 		goto out;
@@ -568,14 +572,22 @@ static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_push(skb, hdr_len);
 
-	work_iph = ah_alloc_tmp(ahash, nfrags, hdr_len + ahp->icv_trunc_len);
+	if (x->props.flags & XFRM_STATE_ESN) {
+		sglists = 1;
+		seqhi_len = sizeof(*seqhi);
+	}
+
+	work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
+				ahp->icv_trunc_len + seqhi_len);
 	if (!work_iph)
 		goto out;
 
-	auth_data = ah_tmp_auth(work_iph, hdr_len);
-	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
+	auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
+	seqhi = auth_data + ahp->icv_trunc_len;
+	icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
 	req = ah_tmp_req(ahash, icv);
 	sg = ah_req_sg(ahash, req);
+	seqhisg = sg + nfrags;
 
 	memcpy(work_iph, ip6h, hdr_len);
 	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
@@ -593,7 +605,15 @@ static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg, 0, skb->len);
 
-	ahash_request_set_crypt(req, sg, icv, skb->len);
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		sg_unmark_end(&sg[nfrags - 1]);
+		/* Attach seqhi sg right after packet payload */
+		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
+		sg_init_table(seqhisg, sglists);
+		sg_set_buf(seqhisg, seqhi, seqhi_len);
+	}
+
+	ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
 	ahash_request_set_callback(req, 0, ah6_input_done, skb);
 
 	AH_SKB_CB(skb)->tmp = work_iph;
-- 
1.7.9.5

[PATCHv2 net-next 5/5] xfrm: Don't prohibit AH from using ESN feature

[Fan Du]

Clear checking when user try to use ESN through netlink keymgr for AH.
As only ESP and AH support ESN feature according to RFC.

Signed-off-by: Fan Du <fan.du@windriver.com>
---
 net/xfrm/xfrm_user.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 97681a3..dbd287d 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -142,7 +142,8 @@ static inline int verify_replay(struct xfrm_usersa_info *p,
 	if (!rt)
 		return 0;
 
-	if (p->id.proto != IPPROTO_ESP)
+	/* As only ESP and AH support ESN feature. */
+	if ((p->id.proto != IPPROTO_ESP) && (p->id.proto != IPPROTO_AH))
 		return -EINVAL;
 
 	if (p->replay_window != 0)
-- 
1.7.9.5