ah4: convert to ahash

This patch converts ah4 to the new ahash interface.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 236 insertions, 59 deletions

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index 5c662703eb1e..d07b0c1dd350 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -1,3 +1,4 @@
+#include <crypto/hash.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <net/ip.h>
@@ -5,10 +6,67 @@
 #include <net/ah.h>
 #include <linux/crypto.h>
 #include <linux/pfkeyv2.h>
-#include <linux/spinlock.h>
+#include <linux/scatterlist.h>
 #include <net/icmp.h>
 #include <net/protocol.h>
 
+struct ah_skb_cb {
+        struct xfrm_skb_cb xfrm;
+        void *tmp;
+};
+
+#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
+
+static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
+                          unsigned int size)
+{
+        unsigned int len;
+
+        len = size + crypto_ahash_digestsize(ahash) +
+              (crypto_ahash_alignmask(ahash) &
+               ~(crypto_tfm_ctx_alignment() - 1));
+
+        len = ALIGN(len, crypto_tfm_ctx_alignment());
+
+        len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
+        len = ALIGN(len, __alignof__(struct scatterlist));
+
+        len += sizeof(struct scatterlist) * nfrags;
+
+        return kmalloc(len, GFP_ATOMIC);
+}
+
+static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
+{
+        return tmp + offset;
+}
+
+static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
+                             unsigned int offset)
+{
+        return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
+}
+
+static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
+                                               u8 *icv)
+{
+        struct ahash_request *req;
+
+        req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
+                                crypto_tfm_ctx_alignment());
+
+        ahash_request_set_tfm(req, ahash);
+
+        return req;
+}
+
+static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
+                                             struct ahash_request *req)
+{
+        return (void *)ALIGN((unsigned long)(req + 1) +
+                             crypto_ahash_reqsize(ahash),
+                             __alignof__(struct scatterlist));
+}
 
 /* Clear mutable options and find final destination to substitute
  * into IP header for icv calculation. Options are already checked
@@ -54,20 +112,72 @@ static int ip_clear_mutable_options(struct iphdr *iph, __be32 *daddr)
         return 0;
 }
 
+static void ah_output_done(struct crypto_async_request *base, int err)
+{
+        u8 *icv;
+        struct iphdr *iph;
+        struct sk_buff *skb = base->data;
+        struct xfrm_state *x = skb_dst(skb)->xfrm;
+        struct ah_data *ahp = x->data;
+        struct iphdr *top_iph = ip_hdr(skb);
+        struct ip_auth_hdr *ah = ip_auth_hdr(skb);
+        int ihl = ip_hdrlen(skb);
+
+        iph = AH_SKB_CB(skb)->tmp;
+        icv = ah_tmp_icv(ahp->ahash, iph, ihl);
+        memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
+
+        top_iph->tos = iph->tos;
+        top_iph->ttl = iph->ttl;
+        top_iph->frag_off = iph->frag_off;
+        if (top_iph->ihl != 5) {
+                top_iph->daddr = iph->daddr;
+                memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
+        }
+
+        err = ah->nexthdr;
+
+        kfree(AH_SKB_CB(skb)->tmp);
+        xfrm_output_resume(skb, err);
+}
+
 static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
 {
         int err;
+        int nfrags;
+        int ihl;
+        u8 *icv;
+        struct sk_buff *trailer;
+        struct crypto_ahash *ahash;
+        struct ahash_request *req;
+        struct scatterlist *sg;
         struct iphdr *iph, *top_iph;
         struct ip_auth_hdr *ah;
         struct ah_data *ahp;
-        union {
-                struct iphdr    iph;
-                char            buf[60];
-        } tmp_iph;
+
+        ahp = x->data;
+        ahash = ahp->ahash;
+
+        if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
+                goto out;
+        nfrags = err;
 
         skb_push(skb, -skb_network_offset(skb));
+        ah = ip_auth_hdr(skb);
+        ihl = ip_hdrlen(skb);
+
+        err = -ENOMEM;
+        iph = ah_alloc_tmp(ahash, nfrags, ihl);
+        if (!iph)
+                goto out;
+
+        icv = ah_tmp_icv(ahash, iph, ihl);
+        req = ah_tmp_req(ahash, icv);
+        sg = ah_req_sg(ahash, req);
+
+        memset(ah->auth_data, 0, ahp->icv_trunc_len);
+
         top_iph = ip_hdr(skb);
-        iph = &tmp_iph.iph;
 
         iph->tos = top_iph->tos;
         iph->ttl = top_iph->ttl;
@@ -78,10 +188,9 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
                 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
                 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
                 if (err)
-                        goto error;
+                        goto out_free;
         }
 
-        ah = ip_auth_hdr(skb);
         ah->nexthdr = *skb_mac_header(skb);
         *skb_mac_header(skb) = IPPROTO_AH;
 
@@ -91,20 +200,31 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
         top_iph->ttl = 0;
         top_iph->check = 0;
 
-        ahp = x->data;
         ah->hdrlen  = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
 
         ah->reserved = 0;
         ah->spi = x->id.spi;
         ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
 
-        spin_lock_bh(&x->lock);
-        err = ah_mac_digest(ahp, skb, ah->auth_data);
-        memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
-        spin_unlock_bh(&x->lock);
+        sg_init_table(sg, nfrags);
+        skb_to_sgvec(skb, sg, 0, skb->len);
 
-        if (err)
-                goto error;
+        ahash_request_set_crypt(req, sg, icv, skb->len);
+        ahash_request_set_callback(req, 0, ah_output_done, skb);
+
+        AH_SKB_CB(skb)->tmp = iph;
+
+        err = crypto_ahash_digest(req);
+        if (err) {
+                if (err == -EINPROGRESS)
+                        goto out;
+
+                if (err == -EBUSY)
+                        err = NET_XMIT_DROP;
+                goto out_free;
+        }
+
+        memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
 
         top_iph->tos = iph->tos;
         top_iph->ttl = iph->ttl;
@@ -114,28 +234,67 @@ static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
                 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
         }
 
-        err = 0;
-
-error:
+out_free:
+        kfree(iph);
+out:
         return err;
 }
 
+static void ah_input_done(struct crypto_async_request *base, int err)
+{
+        u8 *auth_data;
+        u8 *icv;
+        struct iphdr *work_iph;
+        struct sk_buff *skb = base->data;
+        struct xfrm_state *x = xfrm_input_state(skb);
+        struct ah_data *ahp = x->data;
+        struct ip_auth_hdr *ah = ip_auth_hdr(skb);
+        int ihl = ip_hdrlen(skb);
+        int ah_hlen = (ah->hdrlen + 2) << 2;
+
+        work_iph = AH_SKB_CB(skb)->tmp;
+        auth_data = ah_tmp_auth(work_iph, ihl);
+        icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
+
+        err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
+        if (err)
+                goto out;
+
+        skb->network_header += ah_hlen;
+        memcpy(skb_network_header(skb), work_iph, ihl);
+        __skb_pull(skb, ah_hlen + ihl);
+        skb_set_transport_header(skb, -ihl);
+
+        err = ah->nexthdr;
+out:
+        kfree(AH_SKB_CB(skb)->tmp);
+        xfrm_input_resume(skb, err);
+}
+
 static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 {
         int ah_hlen;
         int ihl;
         int nexthdr;
-        int err = -EINVAL;
-        struct iphdr *iph;
+        int nfrags;
+        u8 *auth_data;
+        u8 *icv;
+        struct sk_buff *trailer;
+        struct crypto_ahash *ahash;
+        struct ahash_request *req;
+        struct scatterlist *sg;
+        struct iphdr *iph, *work_iph;
         struct ip_auth_hdr *ah;
         struct ah_data *ahp;
-        char work_buf[60];
+        int err = -ENOMEM;
 
         if (!pskb_may_pull(skb, sizeof(*ah)))
                 goto out;
 
         ah = (struct ip_auth_hdr *)skb->data;
         ahp = x->data;
+        ahash = ahp->ahash;
+
         nexthdr = ah->nexthdr;
         ah_hlen = (ah->hdrlen + 2) << 2;
 
@@ -156,9 +315,24 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 
         ah = (struct ip_auth_hdr *)skb->data;
         iph = ip_hdr(skb);
+        ihl = ip_hdrlen(skb);
+
+        if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
+                goto out;
+        nfrags = err;
+
+        work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
+        if (!work_iph)
+                goto out;
+
+        auth_data = ah_tmp_auth(work_iph, ihl);
+        icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
+        req = ah_tmp_req(ahash, icv);
+        sg = ah_req_sg(ahash, req);
 
-        ihl = skb->data - skb_network_header(skb);
-        memcpy(work_buf, iph, ihl);
+        memcpy(work_iph, iph, ihl);
+        memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
+        memset(ah->auth_data, 0, ahp->icv_trunc_len);
 
         iph->ttl = 0;
         iph->tos = 0;
@@ -166,35 +340,44 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
         iph->check = 0;
         if (ihl > sizeof(*iph)) {
                 __be32 dummy;
-                if (ip_clear_mutable_options(iph, &dummy))
-                        goto out;
+                err = ip_clear_mutable_options(iph, &dummy);
+                if (err)
+                        goto out_free;
         }
 
-        spin_lock(&x->lock);
-        {
-                u8 auth_data[MAX_AH_AUTH_LEN];
+        skb_push(skb, ihl);
 
-                memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
-                skb_push(skb, ihl);
-                err = ah_mac_digest(ahp, skb, ah->auth_data);
-                if (err)
-                        goto unlock;
-                if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len))
-                        err = -EBADMSG;
+        sg_init_table(sg, nfrags);
+        skb_to_sgvec(skb, sg, 0, skb->len);
+
+        ahash_request_set_crypt(req, sg, icv, skb->len);
+        ahash_request_set_callback(req, 0, ah_input_done, skb);
+
+        AH_SKB_CB(skb)->tmp = work_iph;
+
+        err = crypto_ahash_digest(req);
+        if (err) {
+                if (err == -EINPROGRESS)
+                        goto out;
+
+                if (err == -EBUSY)
+                        err = NET_XMIT_DROP;
+                goto out_free;
         }
-unlock:
-        spin_unlock(&x->lock);
 
+        err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
         if (err)
-                goto out;
+                goto out_free;
 
         skb->network_header += ah_hlen;
-        memcpy(skb_network_header(skb), work_buf, ihl);
-        skb->transport_header = skb->network_header;
+        memcpy(skb_network_header(skb), work_iph, ihl);
         __skb_pull(skb, ah_hlen + ihl);
+        skb_set_transport_header(skb, -ihl);
 
-        return nexthdr;
+        err = nexthdr;
 
+out_free:
+        kfree (work_iph);
 out:
         return err;
 }
@@ -222,7 +405,7 @@ static int ah_init_state(struct xfrm_state *x)
 {
         struct ah_data *ahp = NULL;
         struct xfrm_algo_desc *aalg_desc;
-        struct crypto_hash *tfm;
+        struct crypto_ahash *ahash;
 
         if (!x->aalg)
                 goto error;
@@ -231,31 +414,31 @@ static int ah_init_state(struct xfrm_state *x)
                 goto error;
 
         ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
-        if (ahp == NULL)
+        if (!ahp)
                 return -ENOMEM;
 
-        tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
-        if (IS_ERR(tfm))
+        ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
+        if (IS_ERR(ahash))
                 goto error;
 
-        ahp->tfm = tfm;
-        if (crypto_hash_setkey(tfm, x->aalg->alg_key,
-                               (x->aalg->alg_key_len + 7) / 8))
+        ahp->ahash = ahash;
+        if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
+                                (x->aalg->alg_key_len + 7) / 8))
                 goto error;
 
         /*
          * Lookup the algorithm description maintained by xfrm_algo,
          * verify crypto transform properties, and store information
          * we need for AH processing.  This lookup cannot fail here
-         * after a successful crypto_alloc_hash().
+         * after a successful crypto_alloc_ahash().
          */
         aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
         BUG_ON(!aalg_desc);
 
         if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
-            crypto_hash_digestsize(tfm)) {
+            crypto_ahash_digestsize(ahash)) {
                 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
-                       x->aalg->alg_name, crypto_hash_digestsize(tfm),
+                       x->aalg->alg_name, crypto_ahash_digestsize(ahash),
                        aalg_desc->uinfo.auth.icv_fullbits/8);
                 goto error;
         }
@@ -265,10 +448,6 @@ static int ah_init_state(struct xfrm_state *x)
 
         BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
 
-        ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
-        if (!ahp->work_icv)
-                goto error;
-
         x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
                                           ahp->icv_trunc_len);
         if (x->props.mode == XFRM_MODE_TUNNEL)
@@ -279,8 +458,7 @@ static int ah_init_state(struct xfrm_state *x)
 
 error:
         if (ahp) {
-                kfree(ahp->work_icv);
-                crypto_free_hash(ahp->tfm);
+                crypto_free_ahash(ahp->ahash);
                 kfree(ahp);
         }
         return -EINVAL;
@@ -293,8 +471,7 @@ static void ah_destroy(struct xfrm_state *x)
         if (!ahp)
                 return;
 
-        kfree(ahp->work_icv);
-        crypto_free_hash(ahp->tfm);
+        crypto_free_ahash(ahp->ahash);
         kfree(ahp);
 }