[IPSEC]: Use crypto_aead and authenc in ESP

This patch converts ESP to use the crypto_aead interface and in particular
the authenc algorithm.  This lays the foundations for future support of
combined mode algorithms.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 302 insertions, 195 deletions

diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 28ea5c77ca23..c4047223bfbe 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -1,27 +1,118 @@
+#include <crypto/aead.h>
+#include <crypto/authenc.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
 #include <net/esp.h>
 #include <linux/scatterlist.h>
-#include <linux/crypto.h>
 #include <linux/kernel.h>
 #include <linux/pfkeyv2.h>
-#include <linux/random.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/in6.h>
 #include <net/icmp.h>
 #include <net/protocol.h>
 #include <net/udp.h>
 
+struct esp_skb_cb {
+        struct xfrm_skb_cb xfrm;
+        void *tmp;
+};
+
+#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
+
+/*
+ * Allocate an AEAD request structure with extra space for SG and IV.
+ *
+ * For alignment considerations the IV is placed at the front, followed
+ * by the request and finally the SG list.
+ *
+ * TODO: Use spare space in skb for this where possible.
+ */
+static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags)
+{
+        unsigned int len;
+
+        len = crypto_aead_ivsize(aead);
+        if (len) {
+                len += crypto_aead_alignmask(aead) &
+                       ~(crypto_tfm_ctx_alignment() - 1);
+                len = ALIGN(len, crypto_tfm_ctx_alignment());
+        }
+
+        len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
+        len = ALIGN(len, __alignof__(struct scatterlist));
+
+        len += sizeof(struct scatterlist) * nfrags;
+
+        return kmalloc(len, GFP_ATOMIC);
+}
+
+static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp)
+{
+        return crypto_aead_ivsize(aead) ?
+               PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
+}
+
+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;
+
+        req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
+                                crypto_tfm_ctx_alignment());
+        aead_request_set_tfm(req, aead);
+        return req;
+}
+
+static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
+                                             struct aead_request *req)
+{
+        return (void *)ALIGN((unsigned long)(req + 1) +
+                             crypto_aead_reqsize(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;
+
+        kfree(ESP_SKB_CB(skb)->tmp);
+        xfrm_output_resume(skb, err);
+}
+
 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         int err;
         struct ip_esp_hdr *esph;
-        struct crypto_blkcipher *tfm;
-        struct blkcipher_desc desc;
+        struct crypto_aead *aead;
+        struct aead_givcrypt_request *req;
+        struct scatterlist *sg;
+        struct scatterlist *asg;
         struct esp_data *esp;
         struct sk_buff *trailer;
+        void *tmp;
+        u8 *iv;
         u8 *tail;
         int blksize;
         int clen;
@@ -36,18 +127,27 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
         clen = skb->len;
 
         esp = x->data;
-        alen = esp->auth.icv_trunc_len;
-        tfm = esp->conf.tfm;
-        desc.tfm = tfm;
-        desc.flags = 0;
-        blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
+        aead = esp->aead;
+        alen = crypto_aead_authsize(aead);
+
+        blksize = ALIGN(crypto_aead_blocksize(aead), 4);
         clen = ALIGN(clen + 2, blksize);
-        if (esp->conf.padlen)
-                clen = ALIGN(clen, esp->conf.padlen);
+        if (esp->padlen)
+                clen = ALIGN(clen, esp->padlen);
+
+        if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
+                goto error;
+        nfrags = err;
 
-        if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0)
+        tmp = esp_alloc_tmp(aead, nfrags + 1);
+        if (!tmp)
                 goto error;
 
+        iv = esp_tmp_iv(aead, tmp);
+        req = esp_tmp_givreq(aead, iv);
+        asg = esp_givreq_sg(aead, req);
+        sg = asg + 1;
+
         /* Fill padding... */
         tail = skb_tail_pointer(trailer);
         do {
@@ -56,28 +156,34 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
                         tail[i] = i + 1;
         } while (0);
         tail[clen - skb->len - 2] = (clen - skb->len) - 2;
-        pskb_put(skb, trailer, clen - skb->len);
+        tail[clen - skb->len - 1] = *skb_mac_header(skb);
+        pskb_put(skb, trailer, clen - skb->len + alen);
 
         skb_push(skb, -skb_network_offset(skb));
         esph = ip_esp_hdr(skb);
-        *(skb_tail_pointer(trailer) - 1) = *skb_mac_header(skb);
         *skb_mac_header(skb) = IPPROTO_ESP;
 
-        spin_lock_bh(&x->lock);
-
         /* this is non-NULL only with UDP Encapsulation */
         if (x->encap) {
                 struct xfrm_encap_tmpl *encap = x->encap;
                 struct udphdr *uh;
                 __be32 *udpdata32;
+                unsigned int sport, dport;
+                int encap_type;
+
+                spin_lock_bh(&x->lock);
+                sport = encap->encap_sport;
+                dport = encap->encap_dport;
+                encap_type = encap->encap_type;
+                spin_unlock_bh(&x->lock);
 
                 uh = (struct udphdr *)esph;
-                uh->source = encap->encap_sport;
-                uh->dest = encap->encap_dport;
-                uh->len = htons(skb->len + alen - skb_transport_offset(skb));
+                uh->source = sport;
+                uh->dest = dport;
+                uh->len = htons(skb->len - skb_transport_offset(skb));
                 uh->check = 0;
 
-                switch (encap->encap_type) {
+                switch (encap_type) {
                 default:
                 case UDP_ENCAP_ESPINUDP:
                         esph = (struct ip_esp_hdr *)(uh + 1);
@@ -95,131 +201,45 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
         esph->spi = x->id.spi;
         esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
 
-        if (esp->conf.ivlen) {
-                if (unlikely(!esp->conf.ivinitted)) {
-                        get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
-                        esp->conf.ivinitted = 1;
-                }
-                crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
-        }
-
-        do {
-                struct scatterlist *sg = &esp->sgbuf[0];
-
-                if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
-                        sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
-                        if (!sg)
-                                goto unlock;
-                }
-                sg_init_table(sg, nfrags);
-                skb_to_sgvec(skb, sg,
-                             esph->enc_data +
-                             esp->conf.ivlen -
-                             skb->data, clen);
-                err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
-                if (unlikely(sg != &esp->sgbuf[0]))
-                        kfree(sg);
-        } while (0);
-
-        if (unlikely(err))
-                goto unlock;
-
-        if (esp->conf.ivlen) {
-                memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
-                crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
-        }
+        sg_init_table(sg, nfrags);
+        skb_to_sgvec(skb, sg,
+                     esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
+                     clen + alen);
+        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, sizeof(*esph));
+        aead_givcrypt_set_giv(req, esph->enc_data, XFRM_SKB_CB(skb)->seq);
+
+        ESP_SKB_CB(skb)->tmp = tmp;
+        err = crypto_aead_givencrypt(req);
+        if (err == -EINPROGRESS)
+                goto error;
 
-        if (esp->auth.icv_full_len) {
-                err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
-                                     sizeof(*esph) + esp->conf.ivlen + clen);
-                memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
-        }
+        if (err == -EBUSY)
+                err = NET_XMIT_DROP;
 
-unlock:
-        spin_unlock_bh(&x->lock);
+        kfree(tmp);
 
 error:
         return err;
 }
 
-/*
- * Note: detecting truncated vs. non-truncated authentication data is very
- * expensive, so we only support truncated data, which is the recommended
- * and common case.
- */
-static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
+static int esp_input_done2(struct sk_buff *skb, int err)
 {
         struct iphdr *iph;
-        struct ip_esp_hdr *esph;
+        struct xfrm_state *x = xfrm_input_state(skb);
         struct esp_data *esp = x->data;
-        struct crypto_blkcipher *tfm = esp->conf.tfm;
-        struct blkcipher_desc desc = { .tfm = tfm };
-        struct sk_buff *trailer;
-        int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
-        int alen = esp->auth.icv_trunc_len;
-        int elen = skb->len - sizeof(*esph) - esp->conf.ivlen - alen;
-        int nfrags;
+        struct crypto_aead *aead = esp->aead;
+        int alen = crypto_aead_authsize(aead);
+        int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
+        int elen = skb->len - hlen;
         int ihl;
         u8 nexthdr[2];
-        struct scatterlist *sg;
         int padlen;
-        int err = -EINVAL;
 
-        if (!pskb_may_pull(skb, sizeof(*esph)))
-                goto out;
-
-        if (elen <= 0 || (elen & (blksize-1)))
-                goto out;
-
-        if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
-                goto out;
-        nfrags = err;
-
-        skb->ip_summed = CHECKSUM_NONE;
-
-        spin_lock(&x->lock);
-
-        /* If integrity check is required, do this. */
-        if (esp->auth.icv_full_len) {
-                u8 sum[alen];
-
-                err = esp_mac_digest(esp, skb, 0, skb->len - alen);
-                if (err)
-                        goto unlock;
-
-                if (skb_copy_bits(skb, skb->len - alen, sum, alen))
-                        BUG();
-
-                if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
-                        err = -EBADMSG;
-                        goto unlock;
-                }
-        }
-
-        esph = (struct ip_esp_hdr *)skb->data;
-
-        /* Get ivec. This can be wrong, check against another impls. */
-        if (esp->conf.ivlen)
-                crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
-
-        sg = &esp->sgbuf[0];
-
-        if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
-                err = -ENOMEM;
-                sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
-                if (!sg)
-                        goto unlock;
-        }
-        sg_init_table(sg, nfrags);
-        skb_to_sgvec(skb, sg,
-                     sizeof(*esph) + esp->conf.ivlen,
-                     elen);
-        err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
-        if (unlikely(sg != &esp->sgbuf[0]))
-                kfree(sg);
-
-unlock:
-        spin_unlock(&x->lock);
+        kfree(ESP_SKB_CB(skb)->tmp);
 
         if (unlikely(err))
                 goto out;
@@ -229,15 +249,11 @@ unlock:
 
         err = -EINVAL;
         padlen = nexthdr[0];
-        if (padlen+2 >= elen)
+        if (padlen + 2 + alen >= elen)
                 goto out;
 
         /* ... check padding bits here. Silly. :-) */
 
-        /* RFC4303: Drop dummy packets without any error */
-        if (nexthdr[1] == IPPROTO_NONE)
-                goto out;
-
         iph = ip_hdr(skb);
         ihl = iph->ihl * 4;
 
@@ -279,10 +295,87 @@ unlock:
         }
 
         pskb_trim(skb, skb->len - alen - padlen - 2);
-        __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
+        __skb_pull(skb, hlen);
         skb_set_transport_header(skb, -ihl);
 
-        return nexthdr[1];
+        err = nexthdr[1];
+
+        /* RFC4303: Drop dummy packets without any error */
+        if (err == IPPROTO_NONE)
+                err = -EINVAL;
+
+out:
+        return err;
+}
+
+static void esp_input_done(struct crypto_async_request *base, int err)
+{
+        struct sk_buff *skb = base->data;
+
+        xfrm_input_resume(skb, esp_input_done2(skb, err));
+}
+
+/*
+ * Note: detecting truncated vs. non-truncated authentication data is very
+ * expensive, so we only support truncated data, which is the recommended
+ * and common case.
+ */
+static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+        struct ip_esp_hdr *esph;
+        struct esp_data *esp = x->data;
+        struct crypto_aead *aead = esp->aead;
+        struct aead_request *req;
+        struct sk_buff *trailer;
+        int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
+        int nfrags;
+        void *tmp;
+        u8 *iv;
+        struct scatterlist *sg;
+        struct scatterlist *asg;
+        int err = -EINVAL;
+
+        if (!pskb_may_pull(skb, sizeof(*esph)))
+                goto out;
+
+        if (elen <= 0)
+                goto out;
+
+        if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
+                goto out;
+        nfrags = err;
+
+        err = -ENOMEM;
+        tmp = esp_alloc_tmp(aead, nfrags + 1);
+        if (!tmp)
+                goto out;
+
+        ESP_SKB_CB(skb)->tmp = tmp;
+        iv = esp_tmp_iv(aead, tmp);
+        req = esp_tmp_req(aead, iv);
+        asg = esp_req_sg(aead, req);
+        sg = asg + 1;
+
+        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);
+        sg_init_one(asg, esph, sizeof(*esph));
+
+        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, sizeof(*esph));
+
+        err = crypto_aead_decrypt(req);
+        if (err == -EINPROGRESS)
+                goto out;
+
+        err = esp_input_done2(skb, err);
 
 out:
         return err;
@@ -291,11 +384,11 @@ out:
 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
 {
         struct esp_data *esp = x->data;
-        u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
-        u32 align = max_t(u32, blksize, esp->conf.padlen);
+        u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
+        u32 align = max_t(u32, blksize, esp->padlen);
         u32 rem;
 
-        mtu -= x->props.header_len + esp->auth.icv_trunc_len;
+        mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
         rem = mtu & (align - 1);
         mtu &= ~(align - 1);
 
@@ -342,80 +435,98 @@ static void esp_destroy(struct xfrm_state *x)
         if (!esp)
                 return;
 
-        crypto_free_blkcipher(esp->conf.tfm);
-        esp->conf.tfm = NULL;
-        kfree(esp->conf.ivec);
-        esp->conf.ivec = NULL;
-        crypto_free_hash(esp->auth.tfm);
-        esp->auth.tfm = NULL;
-        kfree(esp->auth.work_icv);
-        esp->auth.work_icv = NULL;
+        crypto_free_aead(esp->aead);
         kfree(esp);
 }
 
 static int esp_init_state(struct xfrm_state *x)
 {
         struct esp_data *esp = NULL;
-        struct crypto_blkcipher *tfm;
+        struct crypto_aead *aead;
+        struct crypto_authenc_key_param *param;
+        struct rtattr *rta;
+        char *key;
+        char *p;
+        char authenc_name[CRYPTO_MAX_ALG_NAME];
         u32 align;
+        unsigned int keylen;
+        int err;
 
         if (x->ealg == NULL)
-                goto error;
+                return -EINVAL;
+
+        if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
+                     x->aalg ? x->aalg->alg_name : "digest_null",
+                     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
+                return -ENAMETOOLONG;
 
         esp = kzalloc(sizeof(*esp), GFP_KERNEL);
         if (esp == NULL)
                 return -ENOMEM;
 
+        x->data = esp;
+
+        aead = crypto_alloc_aead(authenc_name, 0, 0);
+        err = PTR_ERR(aead);
+        if (IS_ERR(aead))
+                goto error;
+
+        esp->aead = aead;
+
+        keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
+                 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
+        err = -ENOMEM;
+        key = kmalloc(keylen, GFP_KERNEL);
+        if (!key)
+                goto error;
+
+        p = key;
+        rta = (void *)p;
+        rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
+        rta->rta_len = RTA_LENGTH(sizeof(*param));
+        param = RTA_DATA(rta);
+        p += RTA_SPACE(sizeof(*param));
+
         if (x->aalg) {
                 struct xfrm_algo_desc *aalg_desc;
-                struct crypto_hash *hash;
-
-                hash = crypto_alloc_hash(x->aalg->alg_name, 0,
-                                         CRYPTO_ALG_ASYNC);
-                if (IS_ERR(hash))
-                        goto error;
 
-                esp->auth.tfm = hash;
-                if (crypto_hash_setkey(hash, x->aalg->alg_key,
-                                       (x->aalg->alg_key_len + 7) / 8))
-                        goto error;
+                memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
+                p += (x->aalg->alg_key_len + 7) / 8;
 
                 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
                 BUG_ON(!aalg_desc);
 
+                err = -EINVAL;
                 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
-                    crypto_hash_digestsize(hash)) {
+                    crypto_aead_authsize(aead)) {
                         NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
                                  x->aalg->alg_name,
-                                 crypto_hash_digestsize(hash),
+                                 crypto_aead_authsize(aead),
                                  aalg_desc->uinfo.auth.icv_fullbits/8);
-                        goto error;
+                        goto free_key;
                 }
 
-                esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
-                esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
-
-                esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
-                if (!esp->auth.work_icv)
-                        goto error;
+                err = crypto_aead_setauthsize(
+                        aead, aalg_desc->uinfo.auth.icv_truncbits / 8);
+                if (err)
+                        goto free_key;
         }
 
-        tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
-        if (IS_ERR(tfm))
-                goto error;
-        esp->conf.tfm = tfm;
-        esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
-        esp->conf.padlen = 0;
-        if (esp->conf.ivlen) {
-                esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
-                if (unlikely(esp->conf.ivec == NULL))
-                        goto error;
-                esp->conf.ivinitted = 0;
-        }
-        if (crypto_blkcipher_setkey(tfm, x->ealg->alg_key,
-                                    (x->ealg->alg_key_len + 7) / 8))
+        esp->padlen = 0;
+
+        param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
+        memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
+
+        err = crypto_aead_setkey(aead, key, keylen);
+
+free_key:
+        kfree(key);
+
+        if (err)
                 goto error;
-        x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
+
+        x->props.header_len = sizeof(struct ip_esp_hdr) +
+                              crypto_aead_ivsize(aead);
         if (x->props.mode == XFRM_MODE_TUNNEL)
                 x->props.header_len += sizeof(struct iphdr);
         else if (x->props.mode == XFRM_MODE_BEET)
@@ -434,18 +545,14 @@ static int esp_init_state(struct xfrm_state *x)
                         break;
                 }
         }
-        x->data = esp;
-        align = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
-        if (esp->conf.padlen)
-                align = max_t(u32, align, esp->conf.padlen);
-        x->props.trailer_len = align + 1 + esp->auth.icv_trunc_len;
-        return 0;
+
+        align = ALIGN(crypto_aead_blocksize(aead), 4);
+        if (esp->padlen)
+                align = max_t(u32, align, esp->padlen);
+        x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
 
 error:
-        x->data = esp;
-        esp_destroy(x);
-        x->data = NULL;
-        return -EINVAL;
+        return err;
 }
 
 static struct xfrm_type esp_type =