1 files changed, 531 insertions, 0 deletions

diff --git a/crypto/echainiv.c b/crypto/echainiv.c
new file mode 100644
index 000000000000..e5a9878e6532
--- /dev/null
+++ b/crypto/echainiv.c
@@ -0,0 +1,531 @@
+/*
+ * echainiv: Encrypted Chain IV Generator
+ *
+ * This generator generates an IV based on a sequence number by xoring it
+ * with a salt and then encrypting it with the same key as used to encrypt
+ * the plain text.  This algorithm requires that the block size be equal
+ * to the IV size.  It is mainly useful for CBC.
+ *
+ * This generator can only be used by algorithms where authentication
+ * is performed after encryption (i.e., authenc).
+ *
+ * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <crypto/internal/aead.h>
+#include <crypto/null.h>
+#include <crypto/rng.h>
+#include <crypto/scatterwalk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+
+#define MAX_IV_SIZE 16
+
+struct echainiv_request_ctx {
+        struct scatterlist src[2];
+        struct scatterlist dst[2];
+        struct scatterlist ivbuf[2];
+        struct scatterlist *ivsg;
+        struct aead_givcrypt_request subreq;
+};
+
+struct echainiv_ctx {
+        struct crypto_aead *child;
+        spinlock_t lock;
+        struct crypto_blkcipher *null;
+        u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
+};
+
+static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv);
+
+static int echainiv_setkey(struct crypto_aead *tfm,
+                              const u8 *key, unsigned int keylen)
+{
+        struct echainiv_ctx *ctx = crypto_aead_ctx(tfm);
+
+        return crypto_aead_setkey(ctx->child, key, keylen);
+}
+
+static int echainiv_setauthsize(struct crypto_aead *tfm,
+                                  unsigned int authsize)
+{
+        struct echainiv_ctx *ctx = crypto_aead_ctx(tfm);
+
+        return crypto_aead_setauthsize(ctx->child, authsize);
+}
+
+/* We don't care if we get preempted and read/write IVs from the next CPU. */
+void echainiv_read_iv(u8 *dst, unsigned size)
+{
+        u32 *a = (u32 *)dst;
+        u32 __percpu *b = echainiv_iv;
+
+        for (; size >= 4; size -= 4) {
+                *a++ = this_cpu_read(*b);
+                b++;
+        }
+}
+
+void echainiv_write_iv(const u8 *src, unsigned size)
+{
+        const u32 *a = (const u32 *)src;
+        u32 __percpu *b = echainiv_iv;
+
+        for (; size >= 4; size -= 4) {
+                this_cpu_write(*b, *a);
+                a++;
+                b++;
+        }
+}
+
+static void echainiv_encrypt_compat_complete2(struct aead_request *req,
+                                                 int err)
+{
+        struct echainiv_request_ctx *rctx = aead_request_ctx(req);
+        struct aead_givcrypt_request *subreq = &rctx->subreq;
+        struct crypto_aead *geniv;
+
+        if (err == -EINPROGRESS)
+                return;
+
+        if (err)
+                goto out;
+
+        geniv = crypto_aead_reqtfm(req);
+        scatterwalk_map_and_copy(subreq->giv, rctx->ivsg, 0,
+                                 crypto_aead_ivsize(geniv), 1);
+
+out:
+        kzfree(subreq->giv);
+}
+
+static void echainiv_encrypt_compat_complete(
+        struct crypto_async_request *base, int err)
+{
+        struct aead_request *req = base->data;
+
+        echainiv_encrypt_compat_complete2(req, err);
+        aead_request_complete(req, err);
+}
+
+static void echainiv_encrypt_complete2(struct aead_request *req, int err)
+{
+        struct aead_request *subreq = aead_request_ctx(req);
+        struct crypto_aead *geniv;
+        unsigned int ivsize;
+
+        if (err == -EINPROGRESS)
+                return;
+
+        if (err)
+                goto out;
+
+        geniv = crypto_aead_reqtfm(req);
+        ivsize = crypto_aead_ivsize(geniv);
+
+        echainiv_write_iv(subreq->iv, ivsize);
+
+        if (req->iv != subreq->iv)
+                memcpy(req->iv, subreq->iv, ivsize);
+
+out:
+        if (req->iv != subreq->iv)
+                kzfree(subreq->iv);
+}
+
+static void echainiv_encrypt_complete(struct crypto_async_request *base,
+                                         int err)
+{
+        struct aead_request *req = base->data;
+
+        echainiv_encrypt_complete2(req, err);
+        aead_request_complete(req, err);
+}
+
+static int echainiv_encrypt_compat(struct aead_request *req)
+{
+        struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        struct echainiv_request_ctx *rctx = aead_request_ctx(req);
+        struct aead_givcrypt_request *subreq = &rctx->subreq;
+        unsigned int ivsize = crypto_aead_ivsize(geniv);
+        crypto_completion_t compl;
+        void *data;
+        u8 *info;
+        __be64 seq;
+        int err;
+
+        compl = req->base.complete;
+        data = req->base.data;
+
+        rctx->ivsg = scatterwalk_ffwd(rctx->ivbuf, req->dst, req->assoclen);
+        info = PageHighMem(sg_page(rctx->ivsg)) ? NULL : sg_virt(rctx->ivsg);
+
+        if (!info) {
+                info = kmalloc(ivsize, req->base.flags &
+                                       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
+                                                                  GFP_ATOMIC);
+                if (!info)
+                        return -ENOMEM;
+
+                compl = echainiv_encrypt_compat_complete;
+                data = req;
+        }
+
+        memcpy(&seq, req->iv + ivsize - sizeof(seq), sizeof(seq));
+
+        aead_givcrypt_set_tfm(subreq, ctx->child);
+        aead_givcrypt_set_callback(subreq, req->base.flags,
+                                   req->base.complete, req->base.data);
+        aead_givcrypt_set_crypt(subreq,
+                                scatterwalk_ffwd(rctx->src, req->src,
+                                                 req->assoclen + ivsize),
+                                scatterwalk_ffwd(rctx->dst, rctx->ivsg,
+                                                 ivsize),
+                                req->cryptlen - ivsize, req->iv);
+        aead_givcrypt_set_assoc(subreq, req->src, req->assoclen);
+        aead_givcrypt_set_giv(subreq, info, be64_to_cpu(seq));
+
+        err = crypto_aead_givencrypt(subreq);
+        if (unlikely(PageHighMem(sg_page(rctx->ivsg))))
+                echainiv_encrypt_compat_complete2(req, err);
+        return err;
+}
+
+static int echainiv_encrypt(struct aead_request *req)
+{
+        struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        struct aead_request *subreq = aead_request_ctx(req);
+        crypto_completion_t compl;
+        void *data;
+        u8 *info;
+        unsigned int ivsize;
+        int err;
+
+        aead_request_set_tfm(subreq, ctx->child);
+
+        compl = echainiv_encrypt_complete;
+        data = req;
+        info = req->iv;
+
+        ivsize = crypto_aead_ivsize(geniv);
+
+        if (req->src != req->dst) {
+                struct scatterlist src[2];
+                struct scatterlist dst[2];
+                struct blkcipher_desc desc = {
+                        .tfm = ctx->null,
+                };
+
+                err = crypto_blkcipher_encrypt(
+                        &desc,
+                        scatterwalk_ffwd(dst, req->dst,
+                                         req->assoclen + ivsize),
+                        scatterwalk_ffwd(src, req->src,
+                                         req->assoclen + ivsize),
+                        req->cryptlen - ivsize);
+                if (err)
+                        return err;
+        }
+
+        if (unlikely(!IS_ALIGNED((unsigned long)info,
+                                 crypto_aead_alignmask(geniv) + 1))) {
+                info = kmalloc(ivsize, req->base.flags &
+                                       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
+                                                                  GFP_ATOMIC);
+                if (!info)
+                        return -ENOMEM;
+
+                memcpy(info, req->iv, ivsize);
+        }
+
+        aead_request_set_callback(subreq, req->base.flags, compl, data);
+        aead_request_set_crypt(subreq, req->dst, req->dst,
+                               req->cryptlen - ivsize, info);
+        aead_request_set_ad(subreq, req->assoclen + ivsize, 0);
+
+        crypto_xor(info, ctx->salt, ivsize);
+        scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1);
+        echainiv_read_iv(info, ivsize);
+
+        err = crypto_aead_encrypt(subreq);
+        echainiv_encrypt_complete2(req, err);
+        return err;
+}
+
+static int echainiv_decrypt_compat(struct aead_request *req)
+{
+        struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        struct aead_request *subreq = aead_request_ctx(req);
+        crypto_completion_t compl;
+        void *data;
+        unsigned int ivsize;
+
+        aead_request_set_tfm(subreq, ctx->child);
+
+        compl = req->base.complete;
+        data = req->base.data;
+
+        ivsize = crypto_aead_ivsize(geniv);
+
+        aead_request_set_callback(subreq, req->base.flags, compl, data);
+        aead_request_set_crypt(subreq, req->src, req->dst,
+                               req->cryptlen - ivsize, req->iv);
+        aead_request_set_ad(subreq, req->assoclen, ivsize);
+
+        scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
+
+        return crypto_aead_decrypt(subreq);
+}
+
+static int echainiv_decrypt(struct aead_request *req)
+{
+        struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        struct aead_request *subreq = aead_request_ctx(req);
+        crypto_completion_t compl;
+        void *data;
+        unsigned int ivsize;
+
+        aead_request_set_tfm(subreq, ctx->child);
+
+        compl = req->base.complete;
+        data = req->base.data;
+
+        ivsize = crypto_aead_ivsize(geniv);
+
+        aead_request_set_callback(subreq, req->base.flags, compl, data);
+        aead_request_set_crypt(subreq, req->src, req->dst,
+                               req->cryptlen - ivsize, req->iv);
+        aead_request_set_ad(subreq, req->assoclen + ivsize, 0);
+
+        scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0);
+        if (req->src != req->dst)
+                scatterwalk_map_and_copy(req->iv, req->dst,
+                                         req->assoclen, ivsize, 1);
+
+        return crypto_aead_decrypt(subreq);
+}
+
+static int echainiv_encrypt_compat_first(struct aead_request *req)
+{
+        struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        int err = 0;
+
+        spin_lock_bh(&ctx->lock);
+        if (geniv->encrypt != echainiv_encrypt_compat_first)
+                goto unlock;
+
+        geniv->encrypt = echainiv_encrypt_compat;
+        err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
+                                   crypto_aead_ivsize(geniv));
+
+unlock:
+        spin_unlock_bh(&ctx->lock);
+
+        if (err)
+                return err;
+
+        return echainiv_encrypt_compat(req);
+}
+
+static int echainiv_encrypt_first(struct aead_request *req)
+{
+        struct crypto_aead *geniv = crypto_aead_reqtfm(req);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        int err = 0;
+
+        spin_lock_bh(&ctx->lock);
+        if (geniv->encrypt != echainiv_encrypt_first)
+                goto unlock;
+
+        geniv->encrypt = echainiv_encrypt;
+        err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
+                                   crypto_aead_ivsize(geniv));
+
+unlock:
+        spin_unlock_bh(&ctx->lock);
+
+        if (err)
+                return err;
+
+        return echainiv_encrypt(req);
+}
+
+static int echainiv_compat_init(struct crypto_tfm *tfm)
+{
+        struct crypto_aead *geniv = __crypto_aead_cast(tfm);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        int err;
+
+        spin_lock_init(&ctx->lock);
+
+        crypto_aead_set_reqsize(geniv, sizeof(struct echainiv_request_ctx));
+
+        err = aead_geniv_init(tfm);
+
+        ctx->child = geniv->child;
+        geniv->child = geniv;
+
+        return err;
+}
+
+static int echainiv_init(struct crypto_tfm *tfm)
+{
+        struct crypto_aead *geniv = __crypto_aead_cast(tfm);
+        struct echainiv_ctx *ctx = crypto_aead_ctx(geniv);
+        int err;
+
+        spin_lock_init(&ctx->lock);
+
+        crypto_aead_set_reqsize(geniv, sizeof(struct aead_request));
+
+        ctx->null = crypto_get_default_null_skcipher();
+        err = PTR_ERR(ctx->null);
+        if (IS_ERR(ctx->null))
+                goto out;
+
+        err = aead_geniv_init(tfm);
+        if (err)
+                goto drop_null;
+
+        ctx->child = geniv->child;
+        geniv->child = geniv;
+
+out:
+        return err;
+
+drop_null:
+        crypto_put_default_null_skcipher();
+        goto out;
+}
+
+static void echainiv_compat_exit(struct crypto_tfm *tfm)
+{
+        struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
+
+        crypto_free_aead(ctx->child);
+}
+
+static void echainiv_exit(struct crypto_tfm *tfm)
+{
+        struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm);
+
+        crypto_free_aead(ctx->child);
+        crypto_put_default_null_skcipher();
+}
+
+static struct crypto_template echainiv_tmpl;
+
+static struct crypto_instance *echainiv_aead_alloc(struct rtattr **tb)
+{
+        struct aead_instance *inst;
+        struct crypto_aead_spawn *spawn;
+        struct aead_alg *alg;
+
+        inst = aead_geniv_alloc(&echainiv_tmpl, tb, 0, 0);
+
+        if (IS_ERR(inst))
+                goto out;
+
+        if (inst->alg.ivsize < sizeof(u64) ||
+            inst->alg.ivsize & (sizeof(u32) - 1) ||
+            inst->alg.ivsize > MAX_IV_SIZE) {
+                aead_geniv_free(inst);
+                inst = ERR_PTR(-EINVAL);
+                goto out;
+        }
+
+        spawn = aead_instance_ctx(inst);
+        alg = crypto_spawn_aead_alg(spawn);
+
+        inst->alg.setkey = echainiv_setkey;
+        inst->alg.setauthsize = echainiv_setauthsize;
+        inst->alg.encrypt = echainiv_encrypt_first;
+        inst->alg.decrypt = echainiv_decrypt;
+
+        inst->alg.base.cra_init = echainiv_init;
+        inst->alg.base.cra_exit = echainiv_exit;
+
+        inst->alg.base.cra_alignmask |= __alignof__(u32) - 1;
+        inst->alg.base.cra_ctxsize = sizeof(struct echainiv_ctx);
+        inst->alg.base.cra_ctxsize += inst->alg.base.cra_aead.ivsize;
+
+        if (alg->base.cra_aead.encrypt) {
+                inst->alg.encrypt = echainiv_encrypt_compat_first;
+                inst->alg.decrypt = echainiv_decrypt_compat;
+
+                inst->alg.base.cra_init = echainiv_compat_init;
+                inst->alg.base.cra_exit = echainiv_compat_exit;
+        }
+
+out:
+        return aead_crypto_instance(inst);
+}
+
+static struct crypto_instance *echainiv_alloc(struct rtattr **tb)
+{
+        struct crypto_instance *inst;
+        int err;
+
+        err = crypto_get_default_rng();
+        if (err)
+                return ERR_PTR(err);
+
+        inst = echainiv_aead_alloc(tb);
+
+        if (IS_ERR(inst))
+                goto put_rng;
+
+out:
+        return inst;
+
+put_rng:
+        crypto_put_default_rng();
+        goto out;
+}
+
+static void echainiv_free(struct crypto_instance *inst)
+{
+        aead_geniv_free(aead_instance(inst));
+        crypto_put_default_rng();
+}
+
+static struct crypto_template echainiv_tmpl = {
+        .name = "echainiv",
+        .alloc = echainiv_alloc,
+        .free = echainiv_free,
+        .module = THIS_MODULE,
+};
+
+static int __init echainiv_module_init(void)
+{
+        return crypto_register_template(&echainiv_tmpl);
+}
+
+static void __exit echainiv_module_exit(void)
+{
+        crypto_unregister_template(&echainiv_tmpl);
+}
+
+module_init(echainiv_module_init);
+module_exit(echainiv_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Encrypted Chain IV Generator");
+MODULE_ALIAS_CRYPTO("echainiv");