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esp4: Switch to new AEAD interface
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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>
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Herbert Xu committed May 28, 2015
1 parent 69b0137 commit 7021b2e
Showing 1 changed file with 122 additions and 78 deletions.
200 changes: 122 additions & 78 deletions net/ipv4/esp4.c
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@ static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
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;
Expand All @@ -68,17 +68,6 @@ 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;
Expand All @@ -97,14 +86,6 @@ 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;
Expand All @@ -113,14 +94,37 @@ 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 esp_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;
u8 *iv;
Expand All @@ -129,17 +133,19 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
int clen;
int alen;
int plen;
int ivlen;
int tfclen;
int nfrags;
int assoclen;
int sglists;
int seqhilen;
__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) {
Expand All @@ -160,26 +166,23 @@ static int esp_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;
}

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);
Expand Down Expand Up @@ -235,36 +238,53 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
*skb_mac_header(skb) = IPPROTO_UDP;
}

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);

Expand Down Expand Up @@ -363,6 +383,20 @@ 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);
}

/*
* Note: detecting truncated vs. non-truncated authentication data is very
* expensive, so we only support truncated data, which is the recommended
Expand All @@ -374,19 +408,18 @@ static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
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;
__be32 *seqhi;
void *tmp;
u8 *iv;
struct scatterlist *sg;
struct scatterlist *asg;
int err = -EINVAL;

if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
if (!pskb_may_pull(skb, sizeof(*esph) + ivlen))
goto out;

if (elen <= 0)
Expand All @@ -399,54 +432,55 @@ static int esp_input(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;
}

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

ESP_SKB_CB(skb)->tmp = tmp;
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);

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

if ((x->props.flags & XFRM_STATE_ESN))
esp_input_restore_header(skb);

err = esp_input_done2(skb, err);

out:
Expand Down Expand Up @@ -518,10 +552,16 @@ static void esp_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;
Expand Down Expand Up @@ -560,15 +600,19 @@ 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;
}

Expand Down

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