[v3 PATCH 5/8] esp6: Switch to new AEAD interface

Herbert Xu
2015-05-27T08:03:47Z

This patch makes use of the new AEAD interface which uses a single
SG list instead of separate lists for the AD and plain text. The
IV generation is also now carried out through normal AEAD methods.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

net/ipv6/esp6.c | 200 ++++++++++++++++++++++++++++++++++----------------------
1 file changed, 122 insertions(+), 78 deletions(-)

diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 31f1b5d..060a60b 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -76,7 +76,7 @@ static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
len = ALIGN(len, crypto_tfm_ctx_alignment());
}

- len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
+ len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
len = ALIGN(len, __alignof__(struct scatterlist));

len += sizeof(struct scatterlist) * nfrags;
@@ -96,17 +96,6 @@ static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
}

-static inline struct aead_givcrypt_request *esp_tmp_givreq(
- struct crypto_aead *aead, u8 *iv)
-{
- struct aead_givcrypt_request *req;
-
- req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
- crypto_tfm_ctx_alignment());
- aead_givcrypt_set_tfm(req, aead);
- return req;
-}
-
static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
{
struct aead_request *req;
@@ -125,14 +114,6 @@ static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
__alignof__(struct scatterlist));
}

-static inline struct scatterlist *esp_givreq_sg(
- struct crypto_aead *aead, struct aead_givcrypt_request *req)
-{
- return (void *)ALIGN((unsigned long)(req + 1) +
- crypto_aead_reqsize(aead),
- __alignof__(struct scatterlist));
-}
-
static void esp_output_done(struct crypto_async_request *base, int err)
{
struct sk_buff *skb = base->data;
@@ -141,32 +122,57 @@ static void esp_output_done(struct crypto_async_request *base, int err)
xfrm_output_resume(skb, err);
}

+/* Move ESP header back into place. */
+static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
+{
+ struct ip_esp_hdr *esph = (void *)(skb->data + offset);
+ void *tmp = ESP_SKB_CB(skb)->tmp;
+ __be32 *seqhi = esp_tmp_seqhi(tmp);
+
+ esph->seq_no = esph->spi;
+ esph->spi = *seqhi;
+}
+
+static void esp_output_restore_header(struct sk_buff *skb)
+{
+ esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32));
+}
+
+static void esp_output_done_esn(struct crypto_async_request *base, int err)
+{
+ struct sk_buff *skb = base->data;
+
+ esp_output_restore_header(skb);
+ esp_output_done(base, err);
+}
+
static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
- struct aead_givcrypt_request *req;
+ struct aead_request *req;
struct scatterlist *sg;
- struct scatterlist *asg;
struct sk_buff *trailer;
void *tmp;
int blksize;
int clen;
int alen;
int plen;
+ int ivlen;
int tfclen;
int nfrags;
int assoclen;
- int sglists;
int seqhilen;
u8 *iv;
u8 *tail;
__be32 *seqhi;
+ __be64 seqno;

/* skb is pure payload to encrypt */
aead = x->data;
alen = crypto_aead_authsize(aead);
+ ivlen = crypto_aead_ivsize(aead);

tfclen = 0;
if (x->tfcpad) {
@@ -187,16 +193,14 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
nfrags = err;

assoclen = sizeof(*esph);
- sglists = 1;
seqhilen = 0;

if (x->props.flags & XFRM_STATE_ESN) {
- sglists += 2;
seqhilen += sizeof(__be32);
assoclen += seqhilen;
}

- tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
+ tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
if (!tmp) {
err = -ENOMEM;
goto error;
@@ -204,9 +208,8 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)

seqhi = esp_tmp_seqhi(tmp);
iv = esp_tmp_iv(aead, tmp, seqhilen);
- req = esp_tmp_givreq(aead, iv);
- asg = esp_givreq_sg(aead, req);
- sg = asg + sglists;
+ req = esp_tmp_req(aead, iv);
+ sg = esp_req_sg(aead, req);

/* Fill padding... */
tail = skb_tail_pointer(trailer);
@@ -227,36 +230,53 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
esph = ip_esp_hdr(skb);
*skb_mac_header(skb) = IPPROTO_ESP;

- esph->spi = x->id.spi;
esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);

+ aead_request_set_callback(req, 0, esp_output_done, skb);
+
+ /* For ESN we move the header forward by 4 bytes to
+ * accomodate the high bits. We will move it back after
+ * encryption.
+ */
+ if ((x->props.flags & XFRM_STATE_ESN)) {
+ esph = (void *)(skb_transport_header(skb) - sizeof(__be32));
+ *seqhi = esph->spi;
+ esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
+ aead_request_set_callback(req, 0, esp_output_done_esn, skb);
+ }
+
+ esph->spi = x->id.spi;
+
sg_init_table(sg, nfrags);
skb_to_sgvec(skb, sg,
- esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
- clen + alen);
+ (unsigned char *)esph - skb->data,
+ assoclen + ivlen + clen + alen);

- if ((x->props.flags & XFRM_STATE_ESN)) {
- sg_init_table(asg, 3);
- sg_set_buf(asg, &esph->spi, sizeof(__be32));
- *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
- sg_set_buf(asg + 1, seqhi, seqhilen);
- sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
- } else
- sg_init_one(asg, esph, sizeof(*esph));
-
- aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
- aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
- aead_givcrypt_set_assoc(req, asg, assoclen);
- aead_givcrypt_set_giv(req, esph->enc_data,
- XFRM_SKB_CB(skb)->seq.output.low);
+ aead_request_set_crypt(req, sg, sg, ivlen + clen, iv);
+ aead_request_set_ad(req, assoclen);
+
+ seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
+ ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
+
+ memset(iv, 0, ivlen);
+ memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&seqno + 8 - min(ivlen, 8),
+ min(ivlen, 8));

ESP_SKB_CB(skb)->tmp = tmp;
- err = crypto_aead_givencrypt(req);
- if (err == -EINPROGRESS)
+ err = crypto_aead_encrypt(req);
+
+ switch (err) {
+ case -EINPROGRESS:
goto error;

- if (err == -EBUSY)
+ case -EBUSY:
err = NET_XMIT_DROP;
+ break;
+
+ case 0:
+ if ((x->props.flags & XFRM_STATE_ESN))
+ esp_output_restore_header(skb);
+ }

kfree(tmp);

@@ -317,25 +337,38 @@ static void esp_input_done(struct crypto_async_request *base, int err)
xfrm_input_resume(skb, esp_input_done2(skb, err));
}

+static void esp_input_restore_header(struct sk_buff *skb)
+{
+ esp_restore_header(skb, 0);
+ __skb_pull(skb, 4);
+}
+
+static void esp_input_done_esn(struct crypto_async_request *base, int err)
+{
+ struct sk_buff *skb = base->data;
+
+ esp_input_restore_header(skb);
+ esp_input_done(base, err);
+}
+
static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_esp_hdr *esph;
struct crypto_aead *aead = x->data;
struct aead_request *req;
struct sk_buff *trailer;
- int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
+ int ivlen = crypto_aead_ivsize(aead);
+ int elen = skb->len - sizeof(*esph) - ivlen;
int nfrags;
int assoclen;
- int sglists;
int seqhilen;
int ret = 0;
void *tmp;
__be32 *seqhi;
u8 *iv;
struct scatterlist *sg;
- struct scatterlist *asg;

- if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
+ if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) {
ret = -EINVAL;
goto out;
}
@@ -354,16 +387,14 @@ static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
ret = -ENOMEM;

assoclen = sizeof(*esph);
- sglists = 1;
seqhilen = 0;

if (x->props.flags & XFRM_STATE_ESN) {
- sglists += 2;
seqhilen += sizeof(__be32);
assoclen += seqhilen;
}

- tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
+ tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
if (!tmp)
goto out;

@@ -371,36 +402,39 @@ static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
seqhi = esp_tmp_seqhi(tmp);
iv = esp_tmp_iv(aead, tmp, seqhilen);
req = esp_tmp_req(aead, iv);
- asg = esp_req_sg(aead, req);
- sg = asg + sglists;
+ sg = esp_req_sg(aead, req);

skb->ip_summed = CHECKSUM_NONE;

esph = (struct ip_esp_hdr *)skb->data;

- /* Get ivec. This can be wrong, check against another impls. */
- iv = esph->enc_data;
-
- sg_init_table(sg, nfrags);
- skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
+ aead_request_set_callback(req, 0, esp_input_done, skb);

+ /* For ESN we move the header forward by 4 bytes to
+ * accomodate the high bits. We will move it back after
+ * decryption.
+ */
if ((x->props.flags & XFRM_STATE_ESN)) {
- sg_init_table(asg, 3);
- sg_set_buf(asg, &esph->spi, sizeof(__be32));
- *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
- sg_set_buf(asg + 1, seqhi, seqhilen);
- sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
- } else
- sg_init_one(asg, esph, sizeof(*esph));
+ esph = (void *)skb_push(skb, 4);
+ *seqhi = esph->spi;
+ esph->spi = esph->seq_no;
+ esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.input.hi);
+ aead_request_set_callback(req, 0, esp_input_done_esn, skb);
+ }

- aead_request_set_callback(req, 0, esp_input_done, skb);
- aead_request_set_crypt(req, sg, sg, elen, iv);
- aead_request_set_assoc(req, asg, assoclen);
+ sg_init_table(sg, nfrags);
+ skb_to_sgvec(skb, sg, 0, skb->len);
+
+ aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
+ aead_request_set_ad(req, assoclen);

ret = crypto_aead_decrypt(req);
if (ret == -EINPROGRESS)
goto out;

+ if ((x->props.flags & XFRM_STATE_ESN))
+ esp_input_restore_header(skb);
+
ret = esp_input_done2(skb, ret);

out:
@@ -460,10 +494,16 @@ static void esp6_destroy(struct xfrm_state *x)

static int esp_init_aead(struct xfrm_state *x)
{
+ char aead_name[CRYPTO_MAX_ALG_NAME];
struct crypto_aead *aead;
int err;

- aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
+ err = -ENAMETOOLONG;
+ if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
+ x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
+ goto error;
+
+ aead = crypto_alloc_aead(aead_name, 0, 0);
err = PTR_ERR(aead);
if (IS_ERR(aead))
goto error;
@@ -502,15 +542,19 @@ static int esp_init_authenc(struct xfrm_state *x)

if ((x->props.flags & XFRM_STATE_ESN)) {
if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
- "authencesn(%s,%s)",
+ "%s%sauthencesn(%s,%s)%s",
+ x->geniv ?: "", x->geniv ? "(" : "",
x->aalg ? x->aalg->alg_name : "digest_null",
- x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
+ x->ealg->alg_name,
+ x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
goto error;
} else {
if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
- "authenc(%s,%s)",
+ "%s%sauthenc(%s,%s)%s",
+ x->geniv ?: "", x->geniv ? "(" : "",
x->aalg ? x->aalg->alg_name : "digest_null",
- x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
+ x->ealg->alg_name,
+ x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
goto error;
}